JP3275225B2 - Magnetic toner for developing electrostatic image and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic printing,
The present invention relates to a toner for visualizing an electrostatic latent image in an image forming method such as magnetic recording, and an image forming method using the toner.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
(U.S. Pat. No. 3,666,363) and Japanese Patent Publication No. 43-24748 (U.S. Pat.
As described in US Pat. No. 1,361), a number of methods are known. Generally, a photoconductive substance is used to form an electric latent image on the photoreceptor by various means,
Next, the latent image is developed with a toner to form a visible image, and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heating, pressure, heat and pressure, etc., to obtain a copy or print. The remaining toner that has not been transferred to the photoreceptor is cleaned by various methods, and the above steps are repeated.

Various developing methods for visualizing an electrostatic latent image using toner have been known. For example, U.S. Pat.
The magnetic brush method described in U.S. Pat. No. 4,063, the cascade developing method described in U.S. Pat. No. 2,618,552 and the U.S. Pat. No. 2,221,776. Many developing methods such as a powder cloud method, a fur brush developing method, and a liquid developing method are known. Among these developing methods, in particular, a magnetic brush method, a cascade method, a liquid developing method and the like using a developer mainly composed of a toner and a carrier have been put to practical use. All of these methods are excellent methods for obtaining a good image relatively stably, but have the problems associated with the two-component developer such as deterioration of the carrier and fluctuation of the mixing ratio of the toner and the carrier.

[0004] In order to solve such a problem, various developing methods using a one-component developer consisting only of toner have been proposed. Among them, many are excellent in a method using a developer composed of toner particles having magnetism.

[0005] US Pat. No. 3,909,258 proposes a method of developing using a magnetic toner having electrical conductivity. In this method, a conductive magnetic toner is supported on a cylindrical conductive sleeve having magnetism therein, and the toner is brought into contact with an electrostatic image carrier having an electrostatic image for development. At this time, in the developing unit, a conductive path is formed by toner particles between the surface of the recording medium and the surface of the sleeve,
Electric charges are guided from the sleeve to the magnetic toner particles through the conductive path, and the toner particles adhere to the image area and are developed by the cloning force between the image area of the electrostatic image and the magnetic toner particles. The developing method using the conductive magnetic toner is an excellent method which avoids the problems associated with the conventional two-component developing method. However, since the toner is conductive, it is necessary to remove the toner image from the electrostatic image carrier having a toner image and to a plain paper. It is difficult to transfer electrostatically to the final support member.

As a developing method using a high-resistance magnetic toner capable of electrostatic transfer, there is a developing method utilizing dielectric polarization of toner particles. However, such a method has a problem that the developing speed is essentially low and the density of a developed image is not sufficiently obtained.

[0007] Other development methods using a high-resistance insulating magnetic toner include frictional charging of the magnetic toner particles due to friction between the magnetic toner particles, friction between the magnetic toner particles and a sleeve or the like, and a magnetic material having a triboelectric charge. A method for developing an electrostatic image with toner is known. However, these methods are problematic in that the number of times of contact between the magnetic toner particles and the friction member is so small that triboelectric charging tends to be insufficient, and that the charged magnetic toner particles are liable to agglomerate on the sleeve due to an increased clean force between the sleeve and the sleeve. Have a point.

In Japanese Patent Application Laid-Open No. 55-18656 (corresponding to US Pat. Nos. 4,395,476 and 4473627), a new jumping developing method which eliminates the above-mentioned problems has been proposed. This involves applying a very thin layer of magnetic toner on a sleeve, triboelectrically charging it, and then developing the magnetic toner layer on the sleeve in close proximity to the electrostatic image. This method increases the chance of contact between the sleeve and the magnetic toner by applying the magnetic toner on the sleeve very thinly, enables sufficient frictional charging of the magnetic toner, supports the magnetic toner by magnetic force, and By moving the magnetic toner relatively, the magnetic toner particles can be aggregated with each other and sufficiently rubbed with the sleeve, so that an excellent image can be obtained.

In the insulating toner used in the above-mentioned developing method, a fine powdery magnetic substance is mixed and dispersed in a considerable amount, and a part of the magnetic substance is exposed on the surface of the toner particles. Affects the fluidity and triboelectricity of the magnetic toner. As a result, various characteristics required for the magnetic toner, such as development characteristics and durability of the magnetic toner, are affected.

More specifically, in a conventional jumping developing method using a magnetic toner containing a magnetic substance, if a long-term repeated developing process (for example, copying) is continued, the developer containing the magnetic toner is removed. Liquidity decreases,
Sufficient triboelectricity cannot be obtained, charging tends to be non-uniform, and in a low-temperature and low-humidity environment, a fogging phenomenon is likely to occur, which tends to cause a problem in image quality. When the adhesiveness between the binder resin and the magnetic material constituting the magnetic toner particles is weak, the magnetic material can be removed from the surface of the magnetic toner particles by the repeated development process, and adverse effects such as a decrease in the density of the toner image can be prevented. Tends to give.

When the dispersion of the magnetic material in the magnetic toner particles is not uniform, the magnetic toner particles containing a large amount of the magnetic material and having a small particle diameter accumulate on the sleeve, which is called image density reduction and sleeve ghost. In some cases, shading is observed.

Conventionally, regarding magnetic iron oxides contained in magnetic toners, Japanese Patent Application Laid-Open No. 62-279352 (corresponding US Pat. No. 4,820,603) and Japanese Patent Application Laid-Open No. 62-2781
No. 31 (corresponding US Pat. No. 4,975,214)
Has proposed a magnetic toner containing magnetic iron oxide particles containing a silicon element. Such magnetic iron oxide particles intentionally allow the silicon element to be present inside the magnetic iron oxide particles. However, the fluidity of the magnetic toner containing the magnetic iron oxide particles still has a point to be improved. I have.

Japanese Patent Publication No. 3-9045 (corresponding to European Patent Application Publication No. EP-A187434) proposes to control the shape of magnetic iron oxide particles to be spherical by adding a silicate. Since the magnetic iron oxide particles obtained by this method use silicate to control the particle size, a large amount of silicon element is distributed inside the magnetic iron oxide particles, and the amount of silicon element present on the surface of the magnetic iron oxide particles And the fluidity of the magnetic toner tends to be insufficiently improved.

Japanese Patent Application Laid-Open No. 61-34070 proposes a method for producing ferric oxide by adding a hydroxosilicate solution during the oxidation reaction to ferric oxide. The triiron tetroxide particles obtained by this method have Si
Although the element is present, the Si element exists in a layer near the surface of the triiron tetroxide particles, and has a problem that the surface is weak against mechanical shock such as friction.

In order to solve the above problems, the present inventors have disclosed in Japanese Patent Application Laid-Open No. 5-72801 (corresponding European Patent Application Publication No. EP-A533069) that a magnetic iron oxide particle contains a silicon element, , Near the surface of the magnetic particles,
A magnetic toner containing magnetic iron oxide particles in which 44 to 84% of the total silicon element content is proposed.

However, in the magnetic toner containing the magnetic iron oxide particles, although the fluidity of the toner and the adhesion between the binder resin and the magnetic iron oxide particles are improved, the magnetic toner described in the production example is used. In the iron oxide particles, a large amount of a silicic acid component is present on the outermost surface, a pore structure is formed on the surface of the magnetic iron oxide particles, and the BET specific surface area of the magnetic iron oxide particles increases. The magnetic toner containing particles tends to have considerably reduced triboelectric charging characteristics after being left in a high humidity environment for a long time.

Further, JP-A-4-362954 (corresponding to European Patent Application Publication No. EP-A468525) discloses that
Although magnetic iron oxide particles containing both a silicon element and an aluminum element are disclosed, further improvements in environmental characteristics are desired.

Furthermore, Japanese Patent Application Laid-Open No. Hei 5-213620 discloses a magnetic iron oxide particle containing a silicon component and having a silicon component exposed on the surface. Improvement is desired.

On the other hand, it is also known to coat the surface of the magnetic particle powder with an organic compound or the like. For example,
JP-A-54-122129 discloses a method in which a silane compound is used and JP-A-55-28019 uses a titanium coupling agent to perform a surface coating treatment in an organic solvent. However, in these methods, when the organic solvent is removed, the obtained magnetic particle powder forms a strong aggregate. For this reason, it becomes difficult to uniformly disperse the toner particles in the toner composition, which causes poor charging of the toner and detachment of the magnetic particles from the toner. Further, in the production method as described above, since the reaction efficiency of the treatment agent in the reaction solution is low, unreacted treatment agent that is not economical and does not coat the surface of the magnetic particle powder is unevenly distributed, and the image formation method and It interferes with matching.

Japanese Patent Application Laid-Open No. Hei 3-221965 discloses a method of treating the surface of a magnetic particle powder with a treating agent such as a coupling agent using a wheel-type kneader or a grinder. . According to this method, it is possible to uniformly coat the magnetic particle powder without forming an aggregate, but the immobilization rate becomes low. If the number of OH groups on the surface of the magnetic particle powder is increased or the treatment strength is increased in order to increase the immobilization rate, the amount of FeO in the magnetic particle powder decreases, and the blackness is not sufficient.

On the other hand, Japanese Patent Application Laid-Open No. Hei 6-230604 proposes a method in which oxide fine particles which have been previously subjected to a hydrophobic treatment are fixed by a similar method, but the fixing power of the oxide fine particles is weak. For this reason, the kneading strength is restricted during the production of the toner, and there is a problem in the durability of the toner.

The various properties required for the above-mentioned toners are often reciprocal to each other, and it is increasingly desired in recent years to satisfy them with high performance. Under such circumstances, the role of the magnetic particle powder, which is a toner constituent material, plays a large role, and high functionality is required. However, there is not yet enough comprehensive response to comprehensively address the above issues.

[0023]

SUMMARY OF THE INVENTION It is an object of the present invention to significantly improve the disadvantages of the prior art, realize a high-quality image stably over a long period of time, and adversely affect the photosensitive member and developer carrier. The present invention provides a magnetic toner for developing an electrostatic image, which is highly applicable to an electrophotographic process, and an image forming method using the toner.

[0024]

Means and Action for Solving the Problems The present inventors have
As a result of intensive studies, after optimizing the composition of the inside of the magnetic particle powder and the outermost surface, by forming a coating layer of a compound having a hydrophobic group on the surface of the magnetic particle powder, the reproducibility of dots is improved. It has been found that an excellent, stable and good image can be formed, and the present invention has been completed.

That is, the present invention relates to a magnetic toner for developing an electrostatic image containing at least a binder resin and magnetic particle powder, wherein the magnetic particle powder comprises: (a) a particle surface coated with an organic compound having a hydrophobic group; (B) the magnetic iron oxide particles contain 0.4 to 20% by weight of silicon element (Si) based on iron element (Fe); c) The magnetic toner for developing electrostatic images, wherein the Fe / Si atomic ratio on the outermost surface of the magnetic iron oxide particles before the coating treatment is 1.0 to 4.0.

Further, the present invention is an image forming method using the toner.

Hereinafter, the present invention will be described in detail.

In the magnetic toner for developing electrostatic images of the present invention,
When the content of the silicon element in the magnetic iron oxide particles is
e) is adjusted to be 0.4 to 2.0% by weight and the atomic ratio of Fe / Si on the outermost surface of the magnetic iron oxide particles to be 1.0 to 4.0 based on e). Further, a magnetic particle powder characterized by a two-step treatment of coating the particle surface with an organic compound having a hydrophobic group is used.

In the magnetic iron oxide particles according to the present invention, the silicon element contained in the magnetic iron oxide basically exists both inside and on the outermost surface of the magnetic iron oxide particles. That is, in the production of the magnetic iron oxide particles, by controlling the addition and precipitation conditions of a water-soluble silicate equivalent to 0.4 to 2.0% by weight in terms of silicon element with respect to iron element (Fe). The distribution of the silicon element present in the magnetic iron oxide particles increases continuously or stepwise from the inside toward the surface, and the atomic ratio of Fe / Si on the outermost surface is 1.0 to 4.0. It is adjusted so that it becomes. This allows the silicon compound present on the outermost surface to exist with a strong structure on the surface of the magnetic iron oxide particles, so that even if the magnetic iron oxide particles are added to the toner and used, the surface state hardly changes.

The silicon atom content on the outermost surface of the magnetic iron oxide particles has a correlation with the fluidity and water absorption of the magnetic particle powder of the present invention. It has a great effect on the physical properties of the contained magnetic toner.

When the content of the silicon element in the magnetic iron oxide particles is less than 0.4% by weight and the Fe / Si atomic ratio exceeds 4.0, a large amount of the silicon element exists inside the magnetic iron oxide particles. As a result, the effect of improving the magnetic toner, particularly the degree of improvement in the fluidity of the magnetic toner, is low. Conversely, when the Fe / Si atomic ratio is less than 1.2, most of the silicon element is present near the surface of the magnetic iron oxide particles, which impairs the chargeability in a high humidity environment. Further, when the surface treatment is performed on the magnetic iron oxide particles in such a state, the coating state of the treating agent becomes insufficient.

On the other hand, the content of the silicon element in the magnetic iron oxide particles exceeds 2.0% by weight, and the atomic ratio of Fe / Si is 4.
If it exceeds 0, not only the effect of adding the silicon element is not easily exhibited, but also the magnetic properties of the magnetic iron oxide particles are affected, which is not preferable. Conversely, when the Fe / Si atomic ratio is less than 1.0, not only does the chargeability in a high-humidity environment be impaired, but also the dispersibility in the binder resin decreases, and the development characteristics and This causes a problem in durability.

In the present invention, the Fe / Si atomic ratio at the outermost surface of the magnetic iron oxide particles and the Fe / Al atomic ratio described later are measured by X-ray photoelectron spectroscopy (XPS) under the following conditions.

Apparatus: ESCALAB, 200-X type X-ray photoelectron spectrometer (manufactured by VG) X-ray source: Mg Kα (300 W) Analysis area: 2 mm × 3 mm

The amount of silicon element in the magnetic iron oxide particles can be determined by using a fluorescent X-ray analyzer SYSTEM3080 (manufactured by Rigaku Denki Kogyo KK) according to JIS K0119 “General rules for fluorescent X-ray analysis”. It is determined by performing an analysis.

In the magnetic iron oxide particles according to the present invention, the surface of the magnetic iron oxide particles is preferably controlled after preferably controlling the presence of silicon element both inside and on the outermost surface of the magnetic iron oxide particles. Coating treatment is performed with a modifier.

The reactive surface modifier in the present invention includes silane compounds, titanate compounds, organosilicon compounds and the like.

Examples of the silane compound used for the surface treatment of the magnetic iron oxide particles include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allyl. Phenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldi Examples include siloxane, 1,3-diphenyltetramethyldisiloxane, and the like.

As the titanate compound, isopropoxytitanium triisostearate; isopropoxytitanium dimethacrylate / isostearate; isopropoxytitanium tridodecylbenzenesulfonate; isopropoxytitanium trisodioctyl phosphate; isopropoxytitanium -Tri-N-ethylaminoethyl aminato; titanium bisdioctyl pyrophosphate oxyacetate; bisdioctyl phosphate ethylene dioctyl phosphite; di-n-butoxy bistriethanol aminato titanium and the like.

Examples of the organosilicon compound include silicone oil. Preferably, a silicone oil having a viscosity of 30 to 1000 centistokes at a temperature of 25 ° C. is used. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are preferable.

The surface treating agent having the reactivity as described above is
With respect to 100 parts by weight of magnetic iron oxide particles serving as a processing base,
0.05 to 5 parts by weight are added and a coating treatment is performed. More preferably, 0.1 to 3 parts by weight, particularly preferably 0.1 to 3 parts by weight.
1 to 1.5 parts by weight.

The magnetic particle powder according to the present invention is produced, for example, by the following method.

First, a ferrous hydroxide colloid obtained by reacting an aqueous ferrous salt solution with an aqueous solution of 0.90 to 0.99 equivalents of an alkali hydroxide with respect to Fe ^{2+ in the} aqueous ferrous solution. When magnetite particles are generated by aerating an oxygen-containing gas into a ferrous salt reaction aqueous solution containing, water is previously added to either the alkali hydroxide aqueous solution or the ferrous salt containing the ferrous hydroxide colloid. The total content of soluble silicate in terms of silicon element relative to iron element (0.
4 to 2.0% by weight) and 50 to 99%.
While heating in a temperature range of 0 ° C., an oxygen-containing gas is passed to cause an oxidation reaction, whereby magnetic iron oxide particles containing a silicon element are generated from the ferrous hydroxide colloid. Then, the Fe remaining in the suspension after the completion of the oxidation reaction
1.00 equivalent or more aqueous alkali hydroxide solution and the remaining water-soluble silicate relative to ²⁺ , that is, the total content (0.
4 to 2.0% by weight), and a further 85%
An oxidation reaction is performed while heating in a temperature range of １００100 ° C. to generate magnetic iron oxide particles containing a silicon element.

Next, in the case of treatment with an aluminum hydroxide, a water-soluble aluminum salt is added to the formed particles in the alkaline suspension in which the magnetic iron oxide particles containing the silicon element are formed in terms of aluminum element. After being added to be 0.01 to 2.0% by weight, the pH is adjusted to a range of 6 to 8, and aluminum hydroxide is precipitated on the surface of the magnetic iron oxide. Then, the mixture is filtered, washed with water, dried and crushed.

The surface of these magnetic iron oxide particles is coated with a surface modifier having reactivity as described above. As a method of the coating treatment, there are two methods, a dry treatment method and a wet treatment method. The wet treatment method is a method in which magnetic iron oxide particles are dispersed in water or an organic solvent to form a slurry, and a surface modifier is added with stirring. When added to the toner, uniform dispersion is difficult, which is not preferable. On the other hand, as a dry processing method, a method using a high-speed stirrer such as a Henschel mixer or a spar mixer and a wheel-type kneader such as a Simpson mix mauler,
Alternatively, a method using a grinder may be used, but in the present invention, the surface treatment of the magnetic particle powder is performed, the dispersibility is also improved, and the latter method capable of preferably adjusting the powder characteristics is selected. You. That is, when using a wheel-type kneader, or a milling machine, a surface modifier having a reactivity interposed between the particles of the magnetic particle powder by a compressing action is spread on the surface of the magnetic particle powder, and In the present invention, the aggregation of the magnetic particle powder is released while the surface modifier is extended by the shearing action, and the uniform treatment is performed by the action of a spatula, whereby the individual particle surfaces are highly coated. Such magnetic particle powder is obtained.

In the present invention, as a method of adding the reactive surface modifier to the magnetic iron oxide particles, the reactive surface modifier is sprayed directly or after being dissolved in a solvent having a low boiling point.

In order to promote the fixation of the reactive surface modifier, the heat generation temperature due to friction during the coating treatment and the amount of water held by the magnetic iron oxide particles are controlled as follows.

That is, the heat generation temperature during the coating process is set to 40 to
At 110 ° C., the amount of water retained by the magnetic iron oxide particles is set in the range of 0.4 to 1.0% by weight. This promotes the hydrolysis of the silane and the like and the subsequent condensation reaction as exemplified above, and also allows the decomposition products such as alcohol to be vaporized and removed, which is preferable as the magnetic particle powder for toner. .

The exothermic temperature during the coating process depends on the processing strength (load, load, etc.) of the wheel-type kneader or grinder used.
It may be adjusted by the number of rotations) or the amount of processing, and may be externally heated.

On the other hand, the amount of water retained by the magnetic iron oxide particles is controlled by the silicon element content and the surface structure of the magnetic iron oxide particles as described later.

In the present invention, the water content of the magnetic iron oxide particles is determined in advance by leaving the magnetic iron oxide particles in an environment of 25 ° C./65% RH all day and night, and then measuring the water content of a trace water measuring device AQ manufactured by Hiranuma Sangyo Co., Ltd. Using a Model -6 and an automatic moisture vaporizer SE-24, the sample is heated to 130 ° C. while passing a nitrogen gas carrier at 0.2 L / min, and the amount of evaporated water at that time is measured.

The silicate compound to be added to the magnetic iron oxide particles used in the present invention is exemplified by commercially available silicates such as sodium silicate and silicic acids such as sol silicic acid generated by hydrolysis and the like. . Examples of the water-soluble aluminum salt to be added include aluminum sulfate and the like.

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

Further, as a preferred system of the present invention, the magnetic iron oxide particles have a smoothness of 0.3 to 0.8, preferably 0.1 to 0.8.
45 to 0.7, 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 particles, and when the smoothness is less than 0.3,
There are many pores on the surface of the magnetic iron oxide, which promotes water adsorption.

In the present invention, the smoothness of the magnetic iron oxide particles is determined as follows.

[0056]

(Equation 1)

Here, the actual measurement of the BET specific surface area of the magnetic iron oxide particles is performed as follows.

The BET specific surface area was measured by Yuasa Ionics Co., Ltd., fully automatic gas adsorption amount measuring apparatus: Autosorb 1
And BET multipoint method using nitrogen as the adsorption gas. As pretreatment of the sample, degassing is performed at 50 ° C. for 10 hours.

The measurement of the average particle size and the calculation of the surface area of the magnetic iron oxide particles are performed as follows.

A transmission electron micrograph of the magnetic iron oxide particles was taken, and after arbitrarily selecting 250 particles of 40,000-fold magnification, the Martin diameter of the projected diameters (the projected area in the fixed direction was divided into two equal parts) The length of a line segment to be measured) is measured, and this is represented by a number average diameter.

For the calculation of the surface area, the magnetic iron oxide is assumed to be spherical with the average particle diameter being the diameter, and the density of the magnetic iron oxide is measured by a usual method to determine the value of the surface area.

[0062]

(Equation 2)

In the magnetic particle powder obtained by the above-described production method, the silicon element exists both inside and on the outermost surface of the magnetic iron oxide particles, and is inclined from the center to the outermost surface of the magnetic iron oxide particles. It has increased.

Further, when the magnetic iron oxide particles are treated with aluminum hydroxide, the aluminum element is basically present only on the surface and the surface layer of the magnetic iron oxide particles.

One of the more preferred systems of the present invention includes:
The bulk density of the magnetic iron oxide particles satisfies 0.8 g / cm ³ or more, preferably 1.0 g / cm ³ or more.

The bulk density of the magnetic iron oxide particles is 0.8 g / cm.
If it is less than ^3, not only the coating treatment of the magnetic iron oxide particles with the reactive surface improver becomes insufficient, but also adversely affects the physical mixing with other toner materials during the production of the toner. The dispersibility of the particles decreases.

The bulk density of the magnetic iron oxide particles in the present invention is determined according to the pigment test method of JIS-K-5101.

Further, the magnetic iron oxide particles used in the present invention have an aluminum hydroxide content of 0.01 to 2.0% by weight (more preferably 0.05 to 1.0% by weight) in terms of aluminum element. It is preferably treated with an object.

A part of the aluminum element contained in the magnetic iron oxide particles exists on the surface of the magnetic iron oxide particles in the form of an oxide, a hydroxide, or a hydrated oxide. Since the polarization of the bond between the aluminum element and oxygen is larger than the bond between the transition metal element such as iron and oxygen that constitutes a normal magnetic body and oxygen, the chargeability of the magnetic body containing the aluminum element includes the aluminum element. We believe that it will be better than no magnetic material. This tendency is the same for the silicon element.

When the content is less than 0.01% by weight in terms of aluminum element, the effect is small, and when it exceeds 2.0% by weight, the environmental characteristics of the magnetic toner, particularly the charging characteristics under high humidity, deteriorate. Cheap.

Further, the outermost surface of the magnetic iron oxide particles used in the present invention has an Fe / Al atomic ratio of 0.3 to 1
It is preferably 0.0 (more preferably 0.3 to 5.0, even more preferably 0.3 to 2.0). When the surface of the magnetic iron oxide particles is coated with a reactive surface modifying agent, the presence of a trace amount of an aluminum compound improves the processing efficiency. In particular, it is effective when a silane compound having an alkoxysilyl group or a titanate compound having an alkoxy titanyl group is selected as a surface modifier.

Fe / A on the outermost surface of the magnetic iron oxide particles
If the 1 atomic ratio is less than 0.3, the environmental characteristics of the toner, particularly the charging characteristics under high humidity, tend to deteriorate, and if it exceeds 10.0, the effect of stabilizing the charging cannot be obtained.

The magnetic iron oxide particles used in the present invention have an average particle diameter of 0.1 to 0.4 μm, preferably 0.1 to 0.4 μm.
It preferably has a thickness of about 0.3 μm.

Further, as one of more preferred systems of the present invention, the magnetic iron oxide particles have a BET specific surface area of 15.0 m.
² / g or less, preferably 12.0 m ² / g or less. 14. BET specific surface area of magnetic iron oxide particles is 15.
If it exceeds 0 m ² / g, the water adsorption of the magnetic iron oxide particles increases, which adversely affects the hygroscopicity and chargeability of the magnetic toner containing the magnetic iron oxide particles.

As a result of intensive studies, the present inventors have found that the moisture adsorption characteristics of magnetic iron oxide particles are largely related to the pores on the surface, and that controlling the pore volume is the most important. I found it. The magnetic iron oxide particles have a total pore volume of 7.0 × 10 ^{−3 to} 15.0 × 10 ⁻³ ml /
g, more preferably 8.0 × 10 ^{−3 to} 12.0 × 10
^-3 ml / g is preferred.

The total iron surface pore volume of the magnetic iron oxide particles is 7.0.
If it is less than × 10 ⁻³ ml / g, the water retention capacity of the magnetic iron oxide particles is significantly reduced. Therefore, in a low-humidity environment, the magnetic toner containing the magnetic iron oxide is liable to be charged up and the image density is likely to be reduced.

When the total pore volume exceeds 15.0 × 10 ⁻³ ml / g, the adhesion to the binder resin is weak, and the magnetic iron oxide particles are detached from the magnetic toner particles. It is easy to give adverse effects such as lowering. Furthermore, the surface pores of the magnetic iron oxide particles greatly contribute to the adsorption of water, and greatly affect the water adsorption of the magnetic toner containing the magnetic iron oxide particles. The surface water content of the magnetic toner greatly affects the charging characteristics of the toner. Therefore, in an environment under high humidity, the magnetic toner containing the magnetic iron oxide particles easily absorbs moisture when left to stand, causing a decrease in the charge amount, and as a result, a decrease in image density.

Further, in the magnetic iron oxide particles used in the present invention, in the pore distribution on the surface, the total specific surface area of the pores (micropores) having a pore diameter of less than 20 ° is 20% or more (20 ° to 500 °). Preferably, the total specific surface area of the pores (mesolopores) is not more than the total specific surface area.

The surface pore diameter of the magnetic iron oxide particles has a large effect on water adsorption. In the case of small pores, it is difficult for adsorbed water to desorb. When the total specific surface area of the pores having a pore diameter of less than 20 mm of the magnetic iron oxide particles exceeds the total specific surface area of the pores having a pore diameter of 20 mm or more, more adsorption sites where adsorption water is difficult to desorb are present. In the magnetic toner containing the magnetic iron oxide particles, the charging characteristics are remarkably reduced, especially when left for a long time under high humidity, and it is difficult to recover the charging characteristics.

By controlling the surface structure of the magnetic iron oxide particles used in the present invention as described above, the hysteresis between the adsorption and desorption isotherms in the adsorption and desorption isotherms due to the nitrogen gas of the magnetic iron oxide particles is obtained. (That is, the difference) makes it possible to make the difference in the amount of adsorbed gas in adsorption and desorption at an arbitrary relative pressure 4% or less.

The occurrence of hystericyl (that is, the difference) in the adsorption / desorption isotherm due to nitrogen is caused by the ink bottle type pore having a narrow pore entrance and a wide internal pore in the pore. This has a structure in which the adsorbed substance (water) is hardly desorbed, and adversely affects the charging characteristics of the toner containing the magnetic iron oxide particles, particularly under high humidity. Further, when the surface treatment method as described above is used, the state of coating the surface of the magnetic iron oxide particles with the reactive surface modifier is not uniform.

In the present invention, the total pore volume of the magnetic iron oxide particles, the total specific surface area of pores having a pore diameter of less than 20 °, and a pore diameter of 20
The total specific surface area of 細孔 or more pores and the adsorption isotherm with nitrogen gas are determined as follows.

As a measuring device, a fully automatic gas adsorption device:
Using Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.), nitrogen was used as the adsorption gas, and 40 points of adsorption and 40 points of desorption were measured up to a relative pressure of 0 to 1.0, and d was used.
e Boer's t-plot method, the kelvin equation and the B.E. J. The pore distribution is calculated by the H method, and each is obtained. As pretreatment of the sample, deaeration is performed for 10 hours to 50 ° C.

As described above, by precisely controlling the surface structure of the magnetic iron oxide particles, the surface modifier having reactivity can be uniformly coated on the surface of the particles and the reactivity can be moderately improved. It became possible to promote.

The magnetic toner according to the present invention has an extremely wide feasible temperature range, is excellent in dot reproduction, and has a stable and good toner image without fog for a long time by adding a specific wax described later. It can be formed over.

That is, the dispersibility of the coated magnetic particle powder is improved, and the magnetic particle powder is given a good charging ability.

In this case, the volatile component in the toner is 0.1%.
It is controlled to be less than weight%. Preferably, 0.
It is less than 05% by weight. More preferably, it is less than 0.02% by weight.

In the present invention, the volatile component refers to a solvent or an unreacted monomer used in the production of a binder resin composition described later, or a low-molecular-weight by-product derived from the unreacted monomer, for example, oxidative decomposition of styrene. It contains benzaldehyde and benzoic acid, as well as low molecular weight components remaining in other toner constituent materials and low molecular weight components generated during toner production. Among these, the residual component of the solvent and the unreacted monomer used particularly in the production of the resin increases the plasticizing effect when coexisting with the wax component according to the present invention described later, so that not only the wax component but also the dispersion speed of the magnetic particle powder is increased. On the other hand, growth of the recrystallized wax component and phase separation are also facilitated. Therefore, in the production of toner, by controlling the amount of residual solvent and unreacted monomer before and after the dispersion of the wax component, it is possible to achieve a good dispersion state of the magnetic particle powder and a long-term stabilization in that state. And the various characteristics of the toner are remarkably improved.

That is, the residual solvent amount of the volatile component in the binder resin composition before dispersion of the wax component is 300 to
3,000 ppm and 50 to 3 in terms of unreacted monomer
00 ppm, the residual solvent amount after dispersing the wax component by hot melt kneading or the like is 1,000 ppm or less, and
The amount of the unreacted monomer is controlled within a range of 150 ppm or less.

In the present invention, the volatile component in the toner can be quantitatively determined by using a thermogravimetric method (TG), which measures the weight loss during heating using a thermobalance or the like.
A known method such as a method using gas chromatography (GC) can be applied. GC among these
Is a particularly effective method when fixing the residual components of the solvent and unreacted monomer used in the production of the binder resin for the toner.

In the present invention, the volatile component in the toner is T
In the case of quantification by G, it can be determined from the loss on heating observed when the sample is heated to 200 ° C. Specific examples are described below.

<Measurement Conditions of TG> Apparatus: TGA-7, PE7700 (manufactured by PerkinElmer) Temperature rising rate: 10 ° C./min Measurement environment: under N ₂ atmosphere

A specific example in which the solvent used in the production of the resin in the toner composition and the binder resin and the residual components of the unreacted monomer and the like are determined using GC is described below.

<GC measurement conditions> Apparatus: GC-14A (manufactured by Shimadzu Corporation) Column: fused silica capillary column (J & WS)
(Size: 30m x 0.249mm, liquid phase: DBWA)
X, thickness: 0.25 μm) Sample: 2.55 mg of DMF was used as an internal standard.
Add 100 ml of acetone to make a solvent with internal standard. Next, 400 mg of the developer is made into a 10 ml solution with the above solvent. After 30 minutes on an ultrasonic shaker, leave for 1 hour. Next, the mixture is filtered with a 0.5 μm filter.
The volume of the implanted sample is 4 μl.

Detector: FID (split ratio: 1:20) Carrier gas: N ₂ gas Oven temperature: 70 ° C. → 220 ° C. (After waiting at 70 ° C. for 2 minutes, the temperature is increased at a rate of 5 ° C./min.) Temperature: 200 ° C. Detector temperature: 200 ° C. Calibration curve preparation: DMF similar to the sample solution, gas chromatographic measurement of a standard sample obtained by adding the target monomer to an acetone solution in the same manner, and the weight of the monomer and the internal standard DMF Determine the ratio / area ratio.

The wax component suitable for the present invention has a maximum endothermic peak in the range of 70 to 130 ° C. at the time of temperature rise in a DSC curve measured by a differential scanning calorimeter. It has a maximum exothermic peak at the time of temperature fall in a range of ± 9 ° C.

In the DSC curve at the time of raising the temperature, the wax component melts in the above temperature range, and at the time of toner production, coexists with the volatile component, thereby exerting an appropriate plasticizing effect on the binder resin, and thereby producing a uniform toner composition. Give things. In addition, after the toner is manufactured, the releasing effect of the wax component dispersed uniformly, in addition to the good fixing property, is effectively exhibited, so that a fixing area is secured, and further, the developing characteristics of the toner are improved.

On the other hand, in the DSC curve at the time of temperature decrease, an exothermic peak accompanying the coagulation and crystallization of the wax component is observed.
The presence of this exothermic peak in a temperature region close to the endothermic peak at the time of temperature increase indicates that the wax component is more homogeneous, and by reducing this difference, the thermal responsiveness of the wax component is reduced. At the same time, it is possible to suppress the excessive plasticizing effect at the same time. Therefore, the wax component according to the present invention, when the toner composition containing the wax component is heated by a fixing device, instantly plasticizes a binder resin described below, and greatly contributes to low-temperature fixing, while significantly contributing to low-temperature fixing. The synergistic effect with the resin can also effectively exert the releasability, and it is possible to achieve both low-temperature fixing property and high-temperature offset resistance at a high level. Further, the dispersion of the wax in a homogeneous state does not adversely affect the triboelectric charging, thereby further improving the developing characteristics of the toner. However, such a wax component has a high recrystallization speed and is liable to cause phase separation. Therefore, dispersion of the wax component, deterioration of the toner due to an external force received from the image forming apparatus, and blooming of the wax component due to long-term storage are caused. As described above, the problem was caused by precisely controlling the amount of the volatile component remaining in the toner composition, and the volatile component contained in the toner component before the wax component was dispersed. By controlling the amount, the dispersion state of each toner component was remarkably improved, and various characteristics of the toner were remarkably improved.

The wax preferably used in the present invention is:
It is obtained from the following waxes. Paraffin wax and its derivatives, montan wax and its derivatives, microcrystal wax and its derivatives,
Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, and the derivatives include oxides and block copolymers with vinyl monomers,
Including graft-modified products.

As other waxes, alcohols and derivatives thereof, fatty acids and derivatives thereof, acid amides, esters, ketones, hardened castor oil and derivatives thereof, vegetable waxes, animal waxes, mineral waxes, and petrolactam can also be used. The derivatives include saponified compounds, salts, alkylene oxide adducts, and esters.

Among these, the waxes preferably used are low-molecular-weight polyalkylenes obtained by radical polymerization of alkylene under high pressure or polymerized using a Ziegler catalyst and by-products at this time; high-molecular-weight polyalkylenes are obtained by thermal decomposition. A wax obtained from a low molecular weight polyalkylene; a distillation residue of a hydrocarbon obtained by using a catalyst from a synthesis gas composed of carbon monoxide and hydrogen, or a synthetic hydrocarbon obtained by hydrogenating these; An antioxidant may be added. Alternatively, it is a linear alcohol, alcohol derivative, fatty acid, acid amide, ester or montan derivative. Further, it is also preferable that fatty acid impurities have been removed in advance.

Particularly preferred are those obtained by polymerizing an alkylene such as ethylene with a Ziegler catalyst, and by-products at this time, such as Fischer-Tropsch wax having hydrocarbons having thousands of carbon atoms, especially up to about 1,000 carbon atoms. Is good.

From these waxes, the waxes were separated according to their molecular weights by utilizing the method of press sweating, the solvent method, vacuum distillation, supercritical gas extraction, fractional crystallization (for example, melt liquid crystal precipitation and crystal filtration). Waxes are also preferably used in the present invention. After fractionation, oxidation, block copolymerization, or graft modification may be performed. For example, those obtained by removing low-molecular-weight components, those obtained by extracting low-molecular-weight components,
Further, those having an arbitrary molecular weight distribution such as those obtained by removing low molecular weight components from these.

In particular, adding a low molecular weight wax component to the toner according to the present invention is one of the preferred embodiments of the present invention. These low molecular weight wax components have a weight average molecular weight (Mw) of 30,000 or less, preferably 10,000 or less. More preferably, Mw is 400 to 3,000.
0, the number average molecular weight (Mn) is desirably 200 to 2,000, and Mw / Mn is desirably 3.0 or less.

By providing such a molecular weight distribution, the toner can be provided with preferable physical characteristics. In other words, when the molecular weight is smaller than the above range, the composition is susceptible to thermal or mechanical influences excessively, and causes problems in offset resistance and storage stability. Further, when the molecular weight is larger than the above range, not only the effect of adding the compound is lost, but also a problem occurs in matching with the image forming apparatus.

Further, the low molecular weight wax component preferably used in the present invention has the following general formula RY

[R: represents a hydrocarbon group. Y represents a hydroxyl group, a carboxyl group, an alkyl ether group, an ester group, or a sulfonyl group. The object of the present invention can be attained to a high degree by containing a compound having a weight average molecular weight of 3000 or less by gel permeation chromatography having 60% by weight or more, preferably 70% by weight or more. That is,
Very good matching with the binder resin described below.

Specific examples of the compound include: (A) CH ₃ (CH ₂ ) _n CH ₂ OH (n = about 20 to about 20)
_{0) (B) CH 3 (} CH 2) n CH 2 COOH (n = about 20 to about _{200) (C) CH 3 (} CH 2) n CH 2 OCH 2 (CH 2) m CH 3 (n = about 20 (D) CH ₃ (CH ₂ ) _n CH ₂ COO (CH ₂ ) _m CH ₃ (n = about 20 to about 200, m = 0 to about 100) (E) CH ₃ (CH ₂ ) _n CH ₂ OSO ₃ H (n = about 20 to
About 200). These compounds are derivatives of the compound (A), and the main chain is a linear saturated hydrocarbon. As long as the compound is derived from the compound (A), those other than those shown in the above examples can also be used.

Particularly preferred among the low-molecular weight wax components are those having a carbon number distribution of at least 25, more preferably at least 35, and especially at least 45 in the carbon number distribution measured by gas chromatography (GC). Is preferred. The low molecular weight synthetic wax component, in which the peak appearing according to the number of carbon atoms (one methylene chain) and the intensity of the regularity appears for each carbon number, is easy to control the plastic effect,
It is preferably used in the present invention.

In order to achieve a good balance of toner characteristics such as development characteristics, fixability, and high-temperature offset resistance, the maximum peak should be 25 or more, particularly 30 or more, and more preferably 35 to 150. Some are preferably used.

In the DSC measurement of the present invention, since the exchange of heat of the wax is measured and its behavior is observed, it is preferable from the principle of measurement that the measurement be performed with a high-precision internal heating input compensation type differential scanning calorimeter. For example, DSC-7 manufactured by PerkinElmer can be used.

The measuring method is as described in ASTM D3418-82.
Perform according to. The DSC curve used in the present invention is obtained by raising and lowering the temperature once, taking a pre-history, and then setting a temperature rate of 10 ° C./m
In, a DSC curve measured when the temperature is raised is used.

In the present invention, the molecular weight distribution of the wax is G
It is measured by a PC under the following conditions.

<GPC Measurement Conditions for Wax> Apparatus: GPC-150C (manufactured by Waters) Column: Duplex of GMH-HT (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (added with 0.1% ionol) ) Flow rate: 1.0 ml / min. Sample: 0.4 ml of 0.15% by weight sample is injected

Measurement is performed under the above conditions, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample is used in calculating the molecular weight of the sample. In addition, Mark-Hou
It is calculated by converting to polyethylene using a conversion formula derived from the wink viscosity formula.

In the present invention, the carbon number distribution of the wax is measured by gas chromatography (GC) under the following conditions.

<GC Measurement Conditions> Apparatus: HP 5890 Series II (manufactured by Yokogawa Electric Corporation) Column: SGE HT-56 6 m × 0.53 mm
ID × 0.15 μm Carrier gas: He 20 ml / min Consta
nt FlowMode Oven temperature: 40 ° C → 450 ° C Inlet temperature: 40 ° C → 450 ° C Detector temperature: 450 ° C Detector: FID Inlet: With pressure control

Under the above conditions, the injection port was pressure-controlled, and the measurement was performed while keeping the optimum flow rate constant, and n-paraffin was used as a standard sample.

The binder resin component of the toner according to the present invention is T
In the molecular weight distribution of GPC measured by HF soluble components, a low molecular weight component having a molecular weight of less than 50,000 having a main peak in a region of molecular weight of 2,000 to 30,000 and a subpeak or shoulder in a region of molecular weight of 100,000 or more. Those composed of a high molecular weight component having a molecular weight of 50,000 or more are preferred.

When the peak molecular weight of the high molecular weight component of the binder resin is less than 100,000, not only does the toner not have satisfactory hot offset resistance, but also the wax component according to the present invention retains the dispersibility and dispersion state. Is insufficient, and image defects such as a decrease in image density are likely to occur. Further, when the peak molecular weight of the low molecular weight component of the binder resin is less than 2,000, the plasticization by the wax component becomes abrupt, so that a serious problem occurs in the hot offset resistance and the storage stability. . Further, since phase separation easily occurs locally, the frictional charging of the toner becomes non-uniform, and the developing characteristics deteriorate.
On the other hand, when the peak molecular weight exceeds 30,000, the dispersion state of the wax component is improved to some extent, and although the developing characteristics are improved, the fixability is not sufficient. Further, when the toner is manufactured by a pulverization method or the like, the productivity is reduced.

That is, by specifying the molecular weight distribution of GPC of the binder resin component as described above, it is possible to easily balance various properties required for the toner.

Further, the binder resin component of the toner according to the present invention does not substantially contain a THF-insoluble component, and has a molecular weight of 1,1 in the molecular weight distribution of GPC measured by a THF-soluble component.
The area ratio of the low molecular weight component showing 000 or less is 15% or less, and the area ratio of the high molecular weight component showing the molecular weight of 1,000,000 or more is 0.5 to 25%, so that Very good matching. That is, when the area ratio of the low molecular weight component having a molecular weight of 1,000 or less exceeds 15%, plasticization is rapidly accelerated by the wax component, and the above-mentioned problem becomes more remarkable.
Further, matching with the image forming apparatus, such as fusion of the toner to the surface of the photosensitive drum, may be hindered. On the other hand, molecular weight 1
When the high molecular weight component showing more than 1,000,000 is less than 0.5%,
It is difficult to maintain a good dispersion state of the wax component, and the toner is easily deteriorated by an external force received from the image forming apparatus. For this reason, the developing characteristics and the storability of the toner, and the durability may be deteriorated. In particular, image fog in a low-temperature and low-humidity environment and a decrease in image density in a high-temperature and high-humidity environment become remarkable. Conversely, if the THF-insoluble content or the high molecular weight component having a molecular weight of 1,000,000 or more exceeds 25%, not only the low-temperature fixability and the productivity of the toner are impaired, but also it becomes difficult to uniformly disperse the toner constituent materials. Cannot be obtained, and the developing characteristics deteriorate. Also, even if the mixing force is increased externally by hot-melt kneading or the like during toner production to improve the dispersion state, polymer chains are cut by mechanical shearing force, and the balance between low-temperature fixability and high-temperature offset resistance is maintained. It will be difficult to take. These tendencies become remarkable especially in a magnetic toner in which the particle diameter of the toner is reduced to a fine particle or magnetic particles having a high specific gravity are required to be uniformly dispersed.

Further, in the binder resin component in the toner composition according to the present invention, a high molecular weight component corresponding to a region having a molecular weight of 100,000 or more in the molecular weight distribution of GPC in a THF-soluble component is a polyfunctional polymerization initiator. And / or using a polymer obtained by using a polyfunctional unsaturated monomer to achieve a high degree of low-temperature fixing property and high-temperature offset resistance, and develop the toner without breaking the balance. The characteristics, durability, and storability can be remarkably improved.

The present inventors consider the reason for this as follows.

That is, loose crosslinking that is soluble in THF,
Or by including the high molecular weight component having a branched structure in the toner composition, without increasing the melt viscosity of the toner at the time of heat fixing compared to the conventional crosslinkable polymer,
The elasticity of the semi-molten toner can be maintained. Further, the matching with the wax component according to the present invention is good, and the elasticity as described above is not lost even when plasticized. Thereby, the low-temperature fixing property and the high-temperature offset resistance were remarkably improved. Further, by adding a high molecular weight component having the structure as described above, a low melt viscosity portion plasticized by the volatile component or the wax component that is locally phase-separated by undergoing hot melt kneading during toner production. And the uniform mixing force can be enjoyed in the toner composition, so that the dispersion state is synergistically improved and the developing characteristics of the toner are improved. Further, since the mechanical strength of the toner can be increased, it is possible to suppress the deterioration of the toner against external force received from the image forming apparatus, and the matching with the image forming apparatus becomes easy.

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

<GPC measurement conditions for resin> Apparatus: GPC-150C (manufactured by Waters) Column: KF801 to 7 (manufactured by Shodex) Column: temperature: 40 ° C Solvent: THF 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

A sample is prepared as follows.

After placing the sample in THF and leaving it to stand for several hours, it is shaken well, mixed well with THF (until the sample is no longer united), and left still for 12 hours or more. Then T
The time of leaving in HF is set to 24 hours or more.
After that, the sample processing filter (pore size 0.45
0.5 μm, for example, Myshoridisk H-25
-5 (manufactured by Tosoh Corporation, Exiclodisk 25CR manufactured by Germanic Science Japan) can be used as a GPC sample. The sample concentration is adjusted so that the resin component has the above concentration.

Measurement is performed under the above conditions, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample is used for calculating the molecular weight of the sample.

The toner composition according to the present invention has a substantially T
Preferably, it does not contain HF insolubles. Specifically, the content is 5% by weight or less, preferably 3% by weight or less based on the resin composition.

The THF-insoluble component in the present invention indicates the weight ratio of the polymer component (substantially crosslinked polymer) 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 by a value measured as follows.

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

[0134]

(Equation 3)

If the THF-insoluble content exceeds 5% by weight, high-temperature fixing cannot be achieved at a high degree.

As a method for producing the binder resin preferably used in the present invention, a high-molecular-weight polymer and a low-molecular-weight polymer are separately synthesized by a solution polymerization method, and then they are mixed in a solution state, and then the solvent is removed. Blending method, or dry blending method of melt-kneading with an extruder, etc.,
After producing one polymer component of a high molecular weight polymer or a low molecular weight polymer by a conventionally known polymerization method or the like, the polymer component is dissolved in a monomer giving the other polymer component, and this is dissolved. A so-called two-stage polymerization method of polymerizing to obtain a binder resin may be used. However, with the dry blend method,
There are problems in terms of uniform dispersion and compatibility, and the two-stage polymerization method has many advantages in uniform dispersibility and the like. However, when the polymerization is performed in the presence of a low molecular weight polymer component, the low molecular weight polymer component is used. Not only can be increased than the high molecular weight component,
In the presence of the low molecular weight component, not only is it very difficult to synthesize a sufficient high molecular weight component desired in the present invention, but also disadvantages such as unnecessary low molecular weight components being by-produced are caused. Conversely, in the presence of high molecular weight components, it is difficult to control the degree of polymerization of low molecular weight components, and in particular, the amount of by-products having a molecular weight of 1,000 or less tends to increase, and the conversion of monomers is also sufficient. Therefore, the residual amount of the unreacted monomer in the binder resin tends to increase, which hinders the matching with the wax component according to the present invention. Therefore, the solution blending method is most suitable as the method for producing the binder resin according to the present invention.

The mixing weight ratio of the low molecular weight polymer component and the high molecular weight polymer component of the binder resin according to the present invention is 30: 70-9.
The ratio is 0:10, and particularly 50:50 to 85:15 when produced by a solution blending method. That is, if the amount of the high molecular weight component is more than this range, the fixing property of the toner is deteriorated. Further, the viscosity increases during mixing of the solution, and the compatibility and dispersibility of the constituent components of the binder resin are deteriorated, and the molecular chains of the binder resin are broken. Further, even if such a binder resin and other toner constituent materials are melt-kneaded, poor dispersion and segregation of the toner constituent materials are caused. Conversely, if the amount of the high molecular weight component is less than the above range, not only the high temperature offset resistance of the toner becomes insufficient, but also the development characteristics are deteriorated.

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

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

However, the resulting polymer tends to be impure due to the added emulsifier, and operations such as salting out are required to take out the polymer. To avoid this inconvenience, suspension polymerization is convenient.

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

As the high molecular weight component of the binder resin used in the present invention, in order to achieve the object of the present invention, it is preferable to use a polyfunctional polymerization initiator having a polyfunctional structure as exemplified below.

Specific examples of the polyfunctional polymerization initiator 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 -Butyl peroxybutane, 4,4
-Di-t-butylperoxyvaleric acid-n-
Butyl ester, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, di-t-butylperoxytrimethyladipate, 2,2-bis- (4,4-di-t-butyl Peroxycyclohexyl) propane, 2,2-t-butylperoxyoctane and various polymer oxides, etc., a polyfunctional polymerization initiator having a functional group having a polymerization initiation function such as two or more peroxide groups in one molecule. And 1 such as diallyl peroxydicarbonate, t-butyl peroxymaleic acid, t-butyl peroxyallyl carbonate and t-butyl peroxyisopropyl fumarate
It is selected from a polyfunctional polymerization initiator having both a functional group having a polymerization initiation function such as a peroxide group and a polymerizable unsaturated group in a molecule.

Of these, preferred are 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxycyclohexane, di-tert-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 for a resin composition for a toner.
In particular, the use of a monofunctional polymerization initiator having a decomposition temperature lower than the decomposition temperature for obtaining a half-life of 10 hours of the polyfunctional polymerization initiator improves the developing characteristics of the toner.

More specifically, organic peroxides such as di-t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxybenzoate, etc. And azo compounds such as azobisisobutyronitrile and diazoaminoazobenzene, and diazo compounds.

These monofunctional polymerization initiators may be added to the monomer at the same time as the above-mentioned polyfunctional polymerization initiator. However, in order to maintain the initiator efficiency of the polyfunctional polymerization initiator properly, It is preferable to add the compound after the half-life of the polyfunctional polymerization initiator has elapsed under any polymerization conditions. The monofunctional polymerization initiator is 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 polymer component of the binder resin used in the present invention preferably contains a crosslinkable monomer as exemplified below in order to achieve the object of the present invention.

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

When these crosslinking monomers are used in an amount of 1% by weight or less with respect to 100% by weight of the other monomer components, not only satisfactory low-temperature fixability and anti-offset property are satisfied, but also the storage of toner. The performance is also improved.

Among these crosslinking monomers, those preferably used include aromatic divinyl compounds (particularly divinylbenzene) and diacrylate compounds linked by a chain containing an aromatic group and an ether bond. It is preferable to use it in the range of 0.001 to 0.05% by weight based on 100% by weight of the monomer component. As a result, even when the particle diameter of the toner is reduced, the developing characteristics of the developer under each environment are stabilized, and the durability is improved. Further, it shows good matching with the wax component according to the present invention.

The polymer component of the binder resin of the toner composition according to the present invention contains a monomer unit having at least one of a carboxyl group, a carboxylate group or a carboxylic anhydride group, and contains a developer. The crosslinking reaction may be promoted through a hot-melt kneading step at the time of production. In particular, when a binder resin having a low melt viscosity is used, the components constituting the developer can enjoy a stronger and more uniform shearing force than before, due to the thickening effect of the crosslinking reaction, so that they are synergistic. Not only the dispersibility is improved and the developing property is stabilized, but also the wax component according to the present invention shows good matching.

In order to exhibit a predetermined effect by the crosslinking reaction, it is preferable that a certain amount or more of the above-mentioned carboxyl group capable of forming a crosslinking bond is contained within a range not to impair the developing characteristics. Specifically, the acid value of the polymer-side component constituting the binder resin according to the present invention is adjusted so as to be 0.5 to 30.

As the polymer component having a polar group capable of forming a cross-linking bond of the present invention, a polymer containing at least one of a carboxyl group, a carboxylic anhydride group and a carboxylate group has the best reactivity. Is shown. Examples of the carboxyl group-containing monomer for synthesizing a vinyl polymer include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid and α- or β-acrylic acid thereof.
-Alkyl derivatives, fumaric acid, maleic acid, unsaturated dicarboxylic acids such as citraconic acid and its monoester derivatives or maleic anhydride, etc., such monomers alone or mixed and copolymerized with other monomers Thus, a desired polymer can be produced. Among them, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid.

Examples of the carboxyl group-containing monomer which can be used in the present invention include monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate,
Monoesters of α, β-unsaturated dicarboxylic acids such as monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate, etc .; monobutyl n-butenylsuccinate, monomethyl n-octenylsuccinate, Monoesters of alkenyl dicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenylglutarate and monobutyl n-butenyladipate; monomethyl phthalate, monoethyl phthalate, monobutyl phthalate and the like And monoesters of aromatic dicarboxylic acids.

The carboxyl group-containing monomer as described above may be added in an amount of 1 to 30% by weight, preferably 3 to 20% by weight, based on all monomers constituting the polymer side of the binder resin.

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

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

This alkali treatment may be carried out after the production of the binder resin, by introducing it as an aqueous solution into the solvent used during the polymerization and stirring. Examples of the alkali that can be used in the present invention include 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 pyridium salts. Particularly preferred examples include NaOH and KOH. .

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

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

When the alkali treatment is performed at an equivalent of 0.02 to 5 times the acid value, the concentration of the residual cation ion after the treatment is included in the range of 5 to 1000 ppm, which is preferable for defining the amount of alkali. Can be used.

To the toner according to the present invention, a metal-containing organic compound may be added in order to promote the crosslinking between the polymer chains of the resin composition during the production of the toner, and it is particularly rich in vaporization and sublimation. Those containing an organometallic compound as a ligand or counter ion give excellent results.

Among the organic compounds which form a ligand or a counter ion with a metal ion, those having the above-mentioned properties include, for example, salicylic acid, salicylamide, salicylamine, salicylaldehyde, salicylosalicylic acid, ditert Salicylic acid such as -butylsalicylic acid and derivatives thereof, for example, β-diketones such as acetylacetone and propionacetone, and low-molecular carboxylate salts such as acetate and propionic acid.

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 increasing the reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control.
In this regard, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer depending on the solvent and adjusting the amount of the polymerization initiator and the reaction temperature. It is preferable to obtain a low molecular weight compound in the resin composition used in the present invention. In particular, a solution polymerization method under a pressurized condition is also effective in minimizing the amount of the polymerization initiator used and minimizing the influence of the residue of the polymerization initiator.

The monomers for obtaining the high-molecular component of the binder resin used in the toner of the present invention and the monomers for obtaining the low-molecular component are as follows.

For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
Styrene such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylene , Ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Stearyl, 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 and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds of vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; used alone or in combination of two or more.

These binder resin components are preferably mixed and dispersed in advance with the wax component before producing the toner. In particular, a method is preferred in which the low molecular weight wax component and the high molecular weight polymer are preliminarily dissolved in a solvent during the production of the binder, and then mixed with the low molecular weight polymer solution. By preliminarily mixing the low molecular weight wax component and the high molecular weight component, phase separation in the micro region is reduced, the high molecular weight component is not re-aggregated, and a good dispersion state with the low molecular weight component is obtained.

The solid concentration of the polymer solution is determined by the dispersion efficiency,
In consideration of prevention of deterioration of the resin at the time of stirring, operability, etc., 5 to 70
It is preferably not more than 5% by weight, the preliminary solution of the high molecular weight polymer component and the low molecular weight wax component is preferably 5% to 60% by weight, and the low molecular weight polymer solution is preferably 5% to 70% by weight.

The method for dissolving or dispersing the high molecular weight polymer component and the low molecular weight wax component is performed by stirring and mixing.
A batch type or a continuous type may be used.

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 to carry out stirring and mixing. But it can be continuous.

Examples of the organic solvent used for mixing the solution of the resin composition according to the present invention include benzene, toluene, and toluene.
Xylol, solvent naphtha 1, solvent naphtha 2, solvent naphtha 3, cyclohexane, ethylbenzene, hydrocarbon solvents such as Solvesso 100, Solvesso 150, mineral spirits, methanol, ethanol, iso-propyl alcohol, n-butyl alcohol, alcohol solvents such as sec-butyl alcohol, iso-butyl alcohol, amyl alcohol, and cyclohexanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and ester solvents such as ethyl acetate, n-butyl acetate, and cellosolve acetate. Solvents include ether solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and methyl carbitol. Aromatic in these,
Ketone and ester solvents are preferred. They may be used in combination.

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

A wax component was previously mixed with a binder resin component,
When dispersed, volatile components in the binder resin component,
It is controlled to less than 0.2% by weight. When the residual amount of the volatile component is 0.2% by weight or more, not only the above-mentioned problem caused by plasticization occurs but also the storage stability of the binder resin itself is affected.

The toner resin composition obtained by the above production method is excellent in the compatibility between the low molecular weight polymer and the high molecular weight polymer, not to mention the dispersibility of the low molecular weight wax component, and compared with the conventional method. Thus, significant improvements are made.

The glass transition temperature (Tg) of the resin composition contained in the toner according to the present invention is adjusted to be 50 to 70 ° C. When Tg is lower than 50 ° C., it causes deterioration of the developer in a high-temperature atmosphere and offset during heating and fixing. On the other hand, if the temperature exceeds 70 ° C., the overall fixing property is adversely affected.

In the present invention, the Tg of the resin was measured using a differential thermal analyzer (DSC analyzer), DSC-7 (manufactured by PerkinElmer).

The measurement sample is 5 to 20 mg, preferably 10
Weigh the mg precisely. This is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature increasing rate of 10 ° C./min under normal temperature and normal humidity using an empty aluminum pan as a reference. During this heating process, a temperature of 40 to 100
An endothermic peak of the main peak in the range of ° C is obtained. The intersection between the line at the midpoint of the baseline before and after the endothermic peak appeared and the differential heat curve was obtained.

In the toner of the present invention, it is preferable to add a charge control agent in order to improve charge stability and developability.

Specific examples of the positive charge control agent include generally nigrosine, an azine dye having an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), and a basic dye (for example, CI Basic Yellow). 2 (CI.41
000), C.I. I. Basic Yellow 3, C.I.
I. Basic Red 1 (CI. 45160),
C. I. Basic Red 9 (CI.4250
0), C.I. I. Basic Violet 1 (CI.
42535), C.I. I. Basic Violet 3
(CI. 42555), C.I. I. Basic Violet 10 (CI. 45170), C.I. I. Basic Violet 14 (CI. 42510), C.I.
I. Basic Blue 1 (CI. 42025),
C. I. Basic Blue 3 (CI.5100
5), C.I. I. Basic Blue 5 (CI.421
40), C.I. I. Basic Blue 7 (CI.4
2595), C.I. I. Basic Blue 9 (C.I.
I. 52015), C.I. I. Basic Blue 24
(CI. 52030), C.I. I. Basic Blue 25 (CI.52025), C.I. I. Basic Blue 26 (CI.44025), C.I. I. Basic Green 1 (CI. 42040), C.I. I. Basic Green 4 (CI.42000), etc.
Lake pigments of these basic dyes (as the lacking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.),
C. I. Solvent Black 3 (CI. 2615)
0), Hansa Yellow G (CI. 11680), C.I.
I. Mordrant Black 11, C.I. I. Pigment Black 1 and the like.

Further, for example, polyamide resins such as quaternary ammonium salts such as benzolmethyl-hexadecylammonium chloride and decyl-trimethylammonium chloride, vinyl polymers having an amino group, and condensation polymers having an amino group can be used. Preferably, nigrosine, a quaternary ammonium salt, a triphenylmethane-based nitrogen-containing compound, polyamide or the like is used.

Specific examples of the negative charge control agent are described in JP-B-41-20153, JP-B-42-27596, and JP-B-42-27596.
Metal complexes of monoazo dyes described in JP-A-4-6397 and JP-A-45-26478;
Nitroamine acids and salts thereof described in JP-A-33338; I. Dyes and pigments such as 14645;
No. 42755, No. 58-41508, No. 5
No. 8-7384, JP-B-59-7385 and the like, Z of salicylic acid, naphthoic acid and dicarboxylic acid.
Examples include metal complexes such as n, Al, Co, Cr, and Fe; sulfonated copper phthalocyanine pigments; styrene groups having nitro groups and halogens; and chlorinated paraffins. In particular, from the viewpoint of dispersibility, the general formula [I]
And an organic metal complex of a basic organic acid represented by the general formula [II] are preferable.

[0183]

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[0184]

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[0185]

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Specific examples of the azo metal complex [I] and the basic organic acid metal complex [II] are shown below.

[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0198]

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[0199]

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[0200]

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[0201]

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[0202]

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[0203]

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These metal complexes can be used alone or in combination of two or more.

When the above-mentioned metal complex is used as a charge control agent, the amount of addition is maintained as described above, while maintaining good triboelectricity, the developing power is reduced due to contamination of the developing sleeve surface by the charge control agent, and environmental stability is reduced. 100 parts by weight of the binder resin to minimize the adverse effects
An addition amount of 0.1 to 5 parts by weight is preferred.

It is preferable that the magnetic toner of the present invention contains an inorganic fine powder or a hydrophobic inorganic fine powder in order to improve charge stability, developability, fluidity and durability. For example, it is preferable to use silica fine powder or titanium oxide fine powder alone or in combination.

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

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

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

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

[0211] For the method of silicone oil treatment, for example, silica fine powder treated with a silane coupling agent and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silicone oil may be added to silica as a base. May be injected. Alternatively, it may be prepared by dissolving or dispersing a silicone oil in an appropriate solvent, mixing with a base silica fine powder, and removing the solvent.

Further, a preferred system for hydrophobizing 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. No.

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

[0214] The hydrophobizing treatment of the above silica fine powder and the oil treatment of the titanium oxide fine powder can also be used in the present invention, and it is preferable as in the case of silica.

An external additive other than the silica fine powder may be added to the magnetic toner of the present invention, if necessary.

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

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

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

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

As the inorganic fine particles, for example, a lubricant such as Teflon, zinc stearate and polyvinylidene fluoride, among which polyvinylidene fluoride is preferable. Or an abrasive such as cerium oxide, silicon carbide, strontium titanate,
Among them, strontium titanate is preferable. Alternatively, for example, a fluidity imparting agent such as titanium oxide and aluminum oxide, particularly a hydrophobic agent is preferable. Anti-caking agent,
Alternatively, for example, a conductivity imparting agent such as carbon black, zinc oxide, antimony oxide, tin oxide, or the like, and fine particles of white and black having opposite polarities may be used in a small amount as a developing property improver.

The inorganic fine powder or the hydrophobic inorganic fine powder mixed with the magnetic toner is used in an amount of 0.1 to 5 parts by weight (preferably 0.1 to 3 parts by weight) based on 100 parts by weight of the magnetic toner. Is good.

To prepare a magnetic toner for developing an electrostatic image according to the present invention, a magnetic powder, a vinyl-based or non-vinyl-based thermoplastic resin, a pigment or dye as a colorant as required, a charge control And other additives are thoroughly mixed by a mixer such as a ball mill, and then melted, kneaded and kneaded using a hot kneader such as a heating roll, a kneader, or an extruder to make the resins compatible with each other. The pigment or dye is dispersed or dissolved therein, and after cooling and solidifying, pulverization and strict classification are performed to obtain the magnetic toner according to the present invention.

Further, as another method for obtaining the magnetic toner according to the present invention, the toner can be produced by a polymerization method. The suspension polymerization method toner is obtained by uniformly dissolving or dispersing the polymerizable monomer, the magnetic iron oxide of the present invention, and the polymerization initiator (and, if necessary, a crosslinking agent, a charge control agent and other additives). After preparing the monomer composition, the monomer composition or a prepolymerized version of the monomer composition is dispersed in a continuous phase (eg, water) containing a dispersion stabilizer using a suitable stirrer. And a polymerization reaction is carried out at the same time to obtain toner particles having a desired particle size.

Further, the magnetic toner of the present invention has a weight average diameter D
₄ (μm) is 3.5 ≦ D ₄ ≦ 6.5, and the abundance ratio N of particles of 3.17 μm or less in the number particle size distribution.
Relationship between the (% by number) is preferably having a particle size distribution satisfying the _{35-D 4 × 5 ≦ N} ≦ 180-D 4 × 25.

The toner of the present invention can achieve higher image quality by adjusting the particle size distribution to exhibit a fine particle size as described above. Conventionally, a toner exhibiting such a particle size distribution has excessively triboelectrically charged, thereby causing a reduction in image density and the occurrence of a sleeve ghost.However, these problems have been obviated by using the magnetic particle powder of the present invention. It became possible to avoid.

In the present invention, the particle size distribution of the toner can be measured by various methods such as Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Co., Ltd.).
An interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution using a type II (manufactured by Coulter) and PC9
801 personal computer (manufactured by NEC) is connected, and the electrolyte is 1% NaCl using primary sodium chloride.
Prepare an aqueous solution. For example, ISOTON R-II
(Manufactured by Coulter Scientific Japan) can be used. As a measuring method, the electrolytic aqueous solution 100 to 1
In 50 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number of toner particles having a size of 2 μm or more were measured using a 100 μm aperture as the aperture by the Coulter Counter TA-II. The volume distribution and number distribution were calculated.

The magnetic toner of the present invention has a porosity of 0.50 to 0.50 during packing of the toner as defined by the following formula.
By setting the ratio to 0.70, the charging characteristics of the toner are improved. Porosity = (true density-tap density) / true density

Generally, the toner is charged by friction mainly between the developer carrier and the toner regulating blade. If the frictional charging is repeated in a state where the porosity at the time of packing the toner is less than 0.50, not only the frictional charging becomes excessive, but also the deterioration of the toner particle surface is accelerated. On the other hand, if it exceeds 0.70, sufficient triboelectric charging cannot be obtained. In particular, this tendency is remarkable in the case of the toner having the fine particle diameter as described above.

In the present invention, the true density of the toner is measured as follows.

About 1 g of the toner is put in a tableting machine for IR measurement, and is molded by applying a pressure of about 200 kgf / cm ² for 1 minute. The volume and weight of this sample are measured to determine the density γ.

The tap density of the toner of the present invention was measured using a powder tester manufactured by Hosokawa Micron Corp., using a container attached to the powder tester, and following the procedure described in the instruction manual for the powder tester. Say value.

Next, the image forming method of the present invention will be specifically described with reference to the drawings.

In FIG. 1, reference numeral 100 denotes a photosensitive drum, around which a primary charging roller 117, a developing device 140, a transfer charging roller 114, a cleaner 116, a register roller 124 and the like are provided. And the photosensitive drum 100
Is charged to −800 V by the primary charging roller 117. The photosensitive drum 100 is exposed by irradiating the photosensitive drum 100 with a laser beam 123 by a laser generator 121. The electrostatic latent image on the photosensitive drum 100 is
0, the toner is developed with a one-component magnetic toner, and is transferred onto a transfer material by a transfer roller 114 that is in contact with the photosensitive drum via the transfer material (applied DC voltage of 2 kV). The transfer material on which the toner image has been placed is transferred to the fixing device
26 and is fixed on the transfer material. Further, the toner left partially on the electrostatic latent image carrier is
Cleaning.

As shown in FIG. 2, the developing device 140 has a cylindrical toner carrier 102 (hereinafter referred to as a developing sleeve) made of a non-magnetic metal such as aluminum or stainless steel. The gap between the photosensitive drum 100 and the developing sleeve 102 is maintained at about 300 μm by a sleeve / drum gap holding member (not shown). Further, a stirring rod 141 is provided in the developing device. Inside the developing sleeve, a magnet roller 104 is fixed and disposed concentrically with the developing sleeve 102. However, the developing sleeve 102 is rotatable. The magnet roller 104 is provided with a plurality of magnetic poles as shown in the figure. S ₁ is for development, N ₁ is for controlling the amount of toner coating, S ₂ is for taking in / conveying toner, and N ₂ is for preventing toner blowing. I have. The elastic blade 1 serves as a member for regulating the amount of magnetic toner adhered to and conveyed to the developing sleeve 102.
03 is provided and the developing sleeve 10 of the elastic blade 103 is provided.
The contact pressure with respect to 2 controls the amount of toner conveyed to the development area. In the developing area, a developing bias is applied between the photosensitive drum 100 and the developing sleeve 102, and the toner on the developing sleeve is changed according to the electrostatic latent image.
Fly up and become a visible image.

The toner carrier used in the present invention has a cylindrical substrate such as aluminum and a coating layer for covering the surface of the substrate. FIG. 3 shows a configuration of a toner carrier suitable for the present invention. In FIG. 3, the toner carrier 1 has a base 5 and a coating layer 6. Further, the coating layer 6 includes particles 2 for imparting roughness to the surface of the toner carrier, a binder resin 3 and a conductive material 4.
It consists of.

Since the coating layer contains at least particles for imparting roughness to the surface of the toner carrier, a conductive substance, and a binder resin, good matching with the magnetic toner of the present invention is achieved. . Particles for imparting roughness to the surface of the toner carrier used in the present invention have a number average particle diameter of 0.05 to 100 μm, preferably 0.5 to 50 μm.
μm, particularly 1.0 to 20 μm is good. When the number average particle diameter of the particles is less than 0.05 μm, the toner conveying ability is reduced, and when the number average particle diameter exceeds 100 μm, detachment of the particles from the coating film easily occurs, which is not preferable. Specific examples of particles for imparting roughness to the surface of the toner carrier preferably used in the present invention include, for example, PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene, and copolymers thereof. Resin particles such as benzoguanamine resin, phenol resin, polyamide resin, nylon, fluorine resin, silicone resin, epoxy resin, polyester resin, or silica, alumina, zinc oxide, titanium oxide, zirconium oxide, calcium carbonate, magnetite, ferrite And inorganic compound particles such as glass. Particles for imparting roughness to the toner carrier surface of the present invention,
Particles having the above-mentioned spherical or nearly spherical shape are particularly preferably used. In addition, as particles for imparting roughness to the surface of the toner carrier, inorganic particles and organic particles can be mixed and used. Among the organic particles, crosslinked resin particles are suitable and preferable. In the coating layer used in the present invention, the addition amount of the particles for imparting roughness to the surface of the toner carrier is preferably in the range of 2 to 120 parts by weight with respect to 100 parts by weight of the binder resin. . If the amount is less than 2 parts by weight, the effect of adding the spherical particles is small, and if it exceeds 120 parts by weight, the chargeability of the toner may be too low.

Examples of the conductive substance in the coating layer used in the present invention include carbon black such as furnace black, lamp black, thermal black, acetylene black, and channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide, and titanium oxide. Metal oxides such as potassium acid, antimony oxide and indium oxide; aluminum;
Metals such as copper, silver, nickel, graphite, metal fibers,
Examples include inorganic fillers such as carbon fibers. In the present invention,
Particularly, graphite, carbon black or a mixture of graphite and carbon black is particularly preferably used. As the graphite used in the present invention, any of natural products and artificial synthetic products can be used. Regarding the preferred graphite particle size, it is difficult to unambiguously define the shape of the graphite as a scale-like shape, or because the shape changes during the dispersing step in the production of the toner carrier, but it is difficult to define the graphite in the major axis direction. It is preferable that the width in the direction of the broken surface is 100 μm or less. As a measuring method, the sample is directly observed and measured with a microscope. Particularly preferable results are obtained when the amount of the conductive substance in the coating layer used in the present invention is in the range of 10 to 120 parts by weight based on 100 parts by weight of the binder resin. When the amount is more than 120 parts by weight, the coating strength and the charge amount of the toner are reduced, and when the amount is less than 10 parts by weight, the contamination of the toner on the surface of the coating layer may easily occur.

As the binder resin used in the coating layer of the toner carrier of the present invention, generally known resins can be used. For example, thermoplastic resins such as styrene resin, vinyl resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, cellulose resin, acrylic resin,
A heat or light curable resin such as an epoxy resin, a polyester resin, an alkyd resin, a phenol resin, a melamine resin, a polyurethane resin, a urea resin, a silicone resin, and a polyimide resin can be used. Among them, those having releasability such as silicone resin and fluorine resin, or excellent in mechanical properties such as polyether sulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin and acrylic resin. Are more preferred. The roughness of the surface of the conductive coating layer of the toner carrier of the present invention is 0.2 to 4.5 μm, preferably 0.4 to 3.5 μm, as a center line average roughness (hereinafter, Ra). When the surface roughness is less than 0.2 μm, the toner transportability is reduced, and a sufficient image density may not be obtained. When the surface roughness is more than 4.5 μm, the toner transport amount becomes too large and the toner chargeability becomes poor. Will be enough. The thickness of the conductive coating layer is usually preferably 20 μm or less for obtaining a uniform thickness, but is not particularly limited to this thickness.

In the present invention, a Coulter LS-130 type particle size distribution meter (manufactured by Coulter Co., Ltd.) of a laser diffraction type particle size distribution meter is used for measuring the particle size of the particles for imparting roughness to the surface of the toner carrier. The number average diameter obtained from the number distribution was used.

Further, the center line average roughness (Ra) was determined based on JIS surface roughness (BO601) using a surf coder SE-3300 manufactured by Kosaka Laboratory Co., Ltd.
Six points × two points in the circumferential direction = 6 points were measured, and the average value was used.

[0241]

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

[Production Example of Magnetic Particle Powder and Comparative Production Example] Production examples and comparative production examples of magnetic iron oxide particles used for the magnetic particle powder of the present invention will be described.

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

Thereafter, sodium silicate was added so as to be 1.0% by weight in terms of silicon element with respect to iron element.
Then the temperature 90 to an aqueous ferrous salt solution containing Fe (OH) ₂
Magnetic iron oxide particles containing a silicon element were produced by performing an oxidation reaction under a condition of pH 6 to 7.5 by passing air through at a temperature of ° C.

Further, to this suspension, an aqueous solution of sodium hydroxide in which 0.1% by weight of sodium silicate (in terms of silicon element with respect to iron element) was dissolved was added in an amount of 1.05 equivalent to the remaining Fe ²⁺ , While heating at a temperature of 90 ° C., pH 8
The oxidation reaction was performed under the conditions of 11.5 to produce magnetic iron oxide particles containing silicon element.

The resulting magnetic iron oxide particles were filtered by a conventional method, and then washed and dried. Since the primary particles of the obtained magnetic iron oxide particles are aggregated to form aggregates, the aggregates are crushed using a mix muller to make the magnetic iron oxide particles primary particles, The surface of the iron oxide particles was smoothed to obtain magnetic iron oxide particles (a) having the characteristics shown in Table 1. The average particle size of the magnetic iron oxide particles is 0.21
μm.

Production of Magnetic Iron Oxide Particles (b) and (c) The magnetic iron oxide particles (b) and (b) were prepared in the same manner as in the production of the magnetic iron oxide particles (a) except that the amount of sodium silicate added was changed. c) was obtained.

Production of Magnetic Iron Oxide Particles (d) Aggregates of magnetic iron oxide particles obtained in the same manner as the magnetic iron oxide particles (c) are crushed into primary particles by using a pin mill to obtain magnetic iron oxide particles ( d) was obtained. The magnetic iron oxide particles (d)
As compared with the magnetic iron oxide particles (c), the smoothness is lower and B
The value of the ET specific surface area was large.

Preparation of Magnetic Iron Oxide Particles (e) to (g) A predetermined amount of aluminum sulfate was added to the slurry before the filtration step of the magnetic iron oxide particles (c), and the pH was adjusted to a range of 6 to 8. Magnetic iron oxide particles (e) to (g) were obtained in the same manner except that the surface treatment of the magnetic iron oxide particles was performed as aluminum hydroxide.

Production of Magnetic Iron Oxide Particles (h) and (i) An arbitrary amount of sodium silicate is added during the first stage reaction of the magnetic iron oxide particles (a) to adjust the pH to a range of 8 to 10. Other than that, magnetic iron oxide particles (h) and (i) were obtained in the same manner as in the production of magnetic iron oxide particles (a).

Production of Magnetic Iron Oxide Particles (j) and (k) A predetermined amount of sodium silicate is added to the first stage of the magnetic iron oxide particles (a), and the sodium hydroxide aqueous solution to be added is made of Fe ^{2. +} 1.00 equivalent to ⁺
Were changed to obtain magnetic iron oxide particles (j) and (k).

Production of Magnetic Iron Oxide Particles (l) Sodium silicate was added to an aqueous ferrous sulfate solution so that the content ratio of silicon element to iron element was 1.8%. On the other hand, 1.0 to 1.1 equivalents of an aqueous alkali hydroxide solution were mixed to produce an aqueous ferrous salt solution containing Fe (OH) ₂ .

Then, while maintaining the pH of the aqueous solution at 9, air was passed through at a temperature of 85 ° C. to cause an oxidation reaction, thereby producing magnetic iron oxide particles containing silicon elements. Further, an aqueous solution of ferrous sulfate was added to the suspension so as to have an equivalent amount of 1.1 equivalents to the initial amount of alkali (the sodium component of sodium silicate and the sodium component of alkali hydroxide). Was maintained at 8, and the oxidation reaction was promoted while blowing air in. At the end of the oxidation reaction, the pH was adjusted to a slightly alkaline side to obtain magnetic iron oxide particles.

The resulting magnetic iron oxide particles were washed, filtered, and dried by a conventional method, and then the aggregated magnetic iron oxide particles were crushed by a hammer mill to obtain magnetic iron oxide particles (l). .

[0255] The spherical magnetic iron oxide particles of manufacturing a BET specific surface area of 6.8 m ² / g of magnetic iron oxide particles (m), fine silica powder having a BET specific surface area of 400m ² / g 0.
8 wt% was mixed by a mix muller to obtain magnetic iron oxide particles (m).

Table 1 summarizes various characteristics exhibited by the magnetic iron oxide particles (a) to (m) obtained in the above Production Examples and Comparative Production Examples.

[0257]

[Table 1]

[Example of Surface Coating Treatment of Magnetic Iron Oxide Particles and Comparative Example] Example of Surface Coating Treatment of Magnetic Iron Oxide Particles (a) 100 parts by weight of magnetic iron oxide particles (a) were used as a silylating agent. 0.3 parts by weight of decyltrimethoxysilane was added to Simpson
The magnetic iron oxide particles (a) are charged into a mix muller and operated in a temperature range of 50 to 60 ° C. for 45 minutes.
Was coated with the silylating agent to obtain magnetic particle powder (A) of the present invention.

The BET specific surface area of the obtained magnetic particle powder (A) was 9.8 (m ² / g), and the bulk density was 1.15 (g / g).
cm ³ ), which was almost equal to the value exhibited by the magnetic iron oxide particles (a) before the treatment. No change was observed in the magnetic properties.

Implementation of surface coating treatment of magnetic iron oxide particles (b) to (m)
Example and Comparative Example The magnetic iron oxide particles (b) to (m), the type and amount of the reactive surface modifier, and the type and condition of the treatment apparatus were variously changed. Inventive magnetic particle powder (B)
To (I) and comparative magnetic particle powders (J) to (L) were obtained.

Table 2 shows the main production conditions and various properties of the obtained magnetic particle powder.

[0262]

[Table 2]

Next, the contents of the wax component used in the present invention are summarized in Table 3 together with the measurement results of DSC and GPC.

That is, 75 C of higher alcohol of C ₅₀
Polyethylene wax <A> containing t%, polypropylene wax <B> containing 62 wt% of C ₃₀ higher alcohol, polyethylene wax <C> containing 67 wt% of C ₅₀ higher aliphatic acid, and C ₂₂ higher alcohol. Wax <a> as a main component, wax <b> obtained by pyrolysis of polyethylene, and wax <c> obtained by pyrolysis of polypropylene.

[0265]

[Table 3]

[Production Examples of Binder Resin and Comparative Production Example] Production examples and comparative production examples of a binder resin (resin composition) suitable for the magnetic toner of the present invention will be described.

Production Example 1 of Resin Composition 300 parts by weight of xylene was put into an autoclave made of synthetic glass of a low molecular weight polymer (L-1), and the inside of the vessel was sufficiently purged with nitrogen while stirring, and then
It sealed and heated up to 200 degreeC.

A mixture of 87 parts by weight of styrene, 13 parts by weight of n-butyl acrylate, and 2 parts by weight of di-tert-butyl peroxide was added for 2.5 hours while maintaining a pressurized reflux state at the same temperature. After the dropwise addition, the mixture was held for 1 hour to complete the polymerization, thereby obtaining a low molecular weight polymer (L-1) solution.

A part of the polymer solution was taken out, dried under reduced pressure, and the obtained low molecular weight polymer (L-1) was analyzed. Mw = 8,500, Mn = 4,300, P
Mw = 7,000 and Tg = 60 ° C.

Synthesis of High Molecular Weight Polymer (H-1) 180 parts by weight of degassed water and 20 parts by weight of a 2% by weight aqueous solution of polyvinyl alcohol were charged into a four-necked flask, and 68 parts by weight of styrene and acrylic acid were added. 27 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-
A mixture of 0.1 part by weight of tert-butylperoxycyclohexyl) propane (10-hour half-life temperature; 92 ° C.) was added and stirred to form a suspension.

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

To the suspension after completion of the reaction, an aqueous NaOH solution equivalent to twice the acid value (AV = 8.0) of the obtained high molecular weight polymer (H-1) was added, and the mixture was stirred for 2 hours. Was.

The high molecular weight polymer (H-1) was separated by filtration, washed with water, dried and analyzed.
n = 110,000, PMw = 1.2 million, and Tg = 60 ° C.

Preparation of Binder In a four-necked flask, 100 parts by weight of xylene, 30 parts by weight of the high molecular weight polymer (H-1), and the wax component A (a typical structural formula is CH ₃ (CH ₂ )) ₄₈ parts by weight of higher alcohol wax represented by ₄₈ CH ₂ OH), and the mixture is heated, stirred under reflux, and preliminarily dissolved. After maintaining in this state for 12 hours, a uniform pre-solution (Y-1) of the high molecular weight polymer (H-1) and the wax component A was obtained. The Tg of the solid content in this pre-dissolved solution was 55 ° C.

After the above pre-dissolved solution (Y-1) and 280 parts by weight of the homogeneous solution of the low molecular weight polymer (L-1) were mixed under reflux, the solvent was distilled off, and the obtained resin was cold rolled. After solidification, the mixture was pulverized to obtain a resin composition for toner (I). The molecular weight of the resin composition (I) was measured to be 7,000 and 115.
Mw / Mn was 49 and Tg was 57 ° C.

The resin composition (I) had a volatile component content of 0.13% by weight, a residual xylene content of 990 ppm,
The amount of unreacted styrene was 80 ppm.

Further, when the thin section of the resin composition was observed with a video microscope (manufactured by Wilson), it was confirmed that the resin composition was not re-agglomerated and very good dispersion.

Preparation Example 2 of Resin Composition Preparation of Binder In a four-necked flask, 100 parts by weight of xylene and 30 parts by weight of the high molecular weight polymer (H-1) were charged, and the mixture was heated and refluxed. After stirring for an hour, a homogeneous solution of the high molecular weight polymer (H-1) was obtained.

The above solution was mixed with the low molecular weight polymer (L-
After mixing with 280 parts by weight of the homogeneous solution of 1) under reflux, the solvent was distilled off, and the obtained resin was cold-rolled, solidified and then pulverized to obtain a resin composition for toner (II).

When the molecular weight of the resin composition (II) was measured, it had peaks at 7,000 and 1,0550,000, and Mw /
Mn was 49 and Tg was 60 ° C.

The resin component (II) had a volatile component content of 0.22% by weight and a residual xylene content of 1,700 pp.
m, the amount of unreacted styrene was 300 ppm.

[0282]Production Example 3 of resin composition Synthesis of low molecular weight polymer (L-2)  Put 300 parts by weight of xylene into a glass autoclave.
After stirring and thoroughly replacing the inside of the vessel with nitrogen while stirring,
It sealed and heated up to 200 degreeC.

While maintaining the pressurized reflux state at the same temperature, 70 parts by weight of styrene and di-tert-butyl peroxide 2
A part by weight of the mixed solution was added dropwise over 2.5 hours, and then maintained for 1 hour to complete the polymerization, thereby obtaining a low molecular weight polymer (L-2) solution.

A part of the polymer solution was taken out, dried under reduced pressure, and the obtained low molecular weight polymer (L-2) was analyzed. Mw = 3,500, Mn = 2,500, P
Mw = 3,000, Tg = 60 ° C.

Synthesis of High Molecular Weight Polymer (H-2) 180 parts by weight of degassed water and 20 parts by weight of a 2% by weight aqueous solution of polyvinyl alcohol were charged into a four-necked flask, and then 77 parts by weight of styrene and acrylic acid 23 parts by weight of n-butyl, 0.001 parts by weight of divinylbenzene, and 1.1 parts by weight
-Bis (di-tert-butylperoxy) 3,3,5
Trimethylcyclohexane (10 hour half-life temperature; 9
(0 ° C.) 0.1 part by weight of a mixed solution was added and stirred to form a suspension.

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

The high molecular weight polymer (H-2) was separated by filtration, washed with water, dried and analyzed.
n = 150,000, PMw = 800,000, Tg = 60 ° C.

Preparation of Binder A solution of the high molecular weight polymer (H-2) was prepared in the same manner as in Production Example 2 of the resin composition described above, and the low molecular weight polymer (L-
2) After mixing with 280 parts by weight of the solution under reflux, the solvent was distilled off, and the obtained resin was cold-rolled, solidified and pulverized to obtain a resin composition for toner (III).

When the molecular weight of the resin composition (III) was measured, it had peaks at 3,100 and 810,000, and Mw /
Mn was 49 and Tg was 58 ° C.

The resin component (III) had a volatile component content of 0.27% by weight and a residual xylene content of 1,900 p
pm, and the amount of unreacted styrene was 390 ppm.

Production Example 4 of Resin Composition Production of Binder 300 parts by weight of xylene was charged into a four-necked flask, and the inside of the vessel was sufficiently purged with nitrogen while stirring, and then heated to a reflux temperature.

While maintaining the reflux state at the same temperature, styrene 4
4 parts by weight, 6 parts by weight of n-butyl acrylate, and
1,1-bis (di-tert-butylperoxy) 3,
A mixture of 2 parts by weight of 3,5-trimethylcyclohexane was added dropwise over 3 hours, followed by polymerization for 2 hours. afterwards,
20 parts by weight of styrene, n-butyl acrylate 5
Parts by weight and further 3 parts by weight of tert-butylperoxy-2-ethylhexanoate were added, and after additional polymerization, the solvent was distilled off. The obtained resin was cold-rolled, solidified and then pulverized. A resin composition for toner (IV) was obtained.

Analysis of the resin composition for toner (IV) showed a peak at 25,000, a shoulder at 160,000, Mw / Mn of 17, and Tg of 60 ° C.

The resin composition (IV) had a volatile component of 0.39% by weight and a residual xylene content of 2,700 pp.
m, the amount of unreacted styrene was 900 ppm.

Preparation Example 5 of Resin Composition Preparation of Binder 300 parts by weight of degassed water and 20 parts by weight of a 2% by weight aqueous solution of polyvinyl alcohol were put into a four-necked flask, and then the low molecular weight polymer (L-2) was added. ) 40 parts by weight, styrene 75
Parts by weight, n-butyl acrylate 24 parts by weight, divinylbenzene 1 part by weight, and benzoyl peroxide 4
A part by weight of the mixed solution was added and stirred to form a suspension.

After sufficiently replacing the inside of the flask with nitrogen, 8
The temperature was raised to 5 ° C. to initiate polymerization. The same temperature was maintained for 20 hours to obtain a pearl-shaped resin composition (V).

When the molecular weight of the resin composition (V) was measured, it had a peak at 3,000, formed a shoulder at 110,000, Mw / Mn was 23, and Tg was 63 ° C.

Further, since the amount of volatile components in the resin composition (V) was 0.5% by weight, steam distillation and drying under reduced pressure were repeated to obtain 0.04% by weight of volatile components and 1% of unreacted styrene.
60 ppm and the amount of benzaldehyde were 30 ppm.

Comparative Production Example 1 of Resin Composition : Synthesis of low molecular weight polymer (L-3): 77 parts by weight of styrene, 23 parts by weight of n-butyl acrylate, and 2 parts by weight of di-tert-butyl peroxide. Except for the above-mentioned Production Example 3: Low molecular weight polymer (L-
A low molecular weight polymer (L-3) was obtained in the same manner as in the synthesis of 2).

A part of the polymer solution was taken out, dried under reduced pressure, and the obtained low molecular weight polymer (L-3) was analyzed. As a result, Mw = 35,000, Mn = 20,000,
PMw = 30,000 and Tg = 58 ° C.

Synthesis of High Molecular Weight Polymer (H-3) 180 parts by weight of degassed water and 20 parts by weight of a 2% by weight aqueous solution of polyvinyl alcohol were charged into a four-necked flask, and then 77 parts by weight of styrene and acrylic acid A mixed solution of 23 parts by weight of n-butyl and 0.1 parts by weight of benzoyl peroxide was added and stirred to form a suspension.

After sufficiently replacing the inside of the flask with nitrogen, 8
The temperature was raised to 0 ° C. to initiate polymerization. The polymerization was completed by maintaining the same temperature for 36 hours.

The high molecular weight polymer (H-3) was separated by filtration, washed with water, dried and analyzed. Mw = 960,000, Mn
= 450,000, PMw = 600,000, and Tg = 60 ° C.

Preparation of Binder In a four-necked flask, 100 parts by weight of xylene, 70 parts by weight of the low molecular weight polymer (L-1), and the high molecular weight polymer (H
-3) 30 parts by weight were added, the mixture was heated, stirred and refluxed for 12 hours, mixed, then the organic solvent was distilled off, and the obtained resin was cold-rolled, solidified and pulverized, and then compared with a resin composition for comparison. (I) was obtained.

When the molecular weight of the comparative resin composition (i) was measured, it had peaks at 30,500 and 550,000, and M
w / Mn was 30, and Tg was 60 ° C.

The comparative resin composition (i) had a volatile component of 0.50% by weight and a residual xylene content of 3,900%.
ppm, and the amount of unreacted styrene was 700 ppm.

[0307]

[0308]

[0309]

[0310]

[0311]

[0312]

[0313]

[0314]

[0315]

[0316]

[0317]

[0318]

[0319]

[0320]

[0321]

[0322]

[Toner Production Examples and Comparative Production Examples] Production examples and comparative production examples of the magnetic toner of the invention will be described.

Toner Production Example 1 100 parts by weight of magnetic particle powder (A) obtained in Production Example of Magnetic Particle Powder 100 parts by weight of resin composition (I) obtained in Production Example 1 of Resin Composition Negative charge control agent (monoazo iron complex represented by the following structural formula) 2 parts by weight

[0325]

Embedded image

The above mixture was melt-kneaded with a twin-screw extruder heated to 130 ° C., and the cooled kneaded material was coarsely pulverized with a hammer mill, and the coarsely pulverized material was finely pulverized with a jet mill. The powder was classified with a fixed wall air classifier to produce a classified powder. Further, the obtained classified powder is strictly classified and removed by a multi-division classifier utilizing a Coanda effect (an elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.) at the same time to remove the weight average particle diameter (D ₄ ). Of 5.4 μm was obtained. The proportion (N) of particles having a size of 3.17 μm or less in the number particle size distribution was 22%.

Hydrogenated silica fine powder (BET 300 m ² / g) treated with 100 parts by weight of the magnetic toner classification powder, treated with dimethyldichlorosilane, treated with hexamethyldisilazane, and then treated with dimethylsilicone oil.
2 parts by weight were dry-mixed with a Henschel mixer to prepare a magnetic toner (1) of the present invention. The porosity of the magnetic toner was 0.62.

Toner Production Examples 2 to 13, and Comparative Production Examples 1 to 6 The magnetic particle powders (B) to (I) obtained in the above magnetic particle powder production examples and the comparative production examples (J) to (L) And the magnetic iron oxide (l) obtained in the production example of the magnetic iron oxide particles,
Except for using (m), magnetic toners (2) to (13) of the present invention and comparative magnetic toners (19) to (23) were prepared in the same manner as in Production Example 1 of the toner.

At this time, the THF insoluble content of the magnetic toner (1) was 1.5% by weight, and the volatile component was 0.016% by weight. When the molecular weight of the magnetic toner (1) was measured, it had peaks at 7000 and 850,000 and a molecular weight of 1000
The following area% was 7.0%, and the area% having a molecular weight of 1,000,000 or more was 15.6%.

The magnetic toners (1) to (1) obtained above
Table 4 summarizes the prescription contents and various properties of 3) and comparative magnetic toners (19 to (23)).

[0331]

[Table 4]

Production Example 14 of Toner 100 parts by weight of magnetic particle powder obtained in Production Example of Magnetic Particle Powder 100 parts by weight of resin composition (II) obtained in Production Example 2 of Resin Composition Table 3 above 7 parts by weight of a wax component <A> 2 parts by weight of a negative charge control agent (salicylate-based iron complex represented by the following structural formula)

[0333]

Embedded image

The above mixture was treated in the same manner as in Preparation Example 1 of the toner to obtain a magnetic toner classified powder having a weight average diameter (D ₄ ) of 5.5 μm. 3.17 μm in the number particle size distribution
The existence ratio (N) of the following particles was 18%.

100 parts by weight of the magnetic toner classification powder, 1.2 parts by weight of hydrophobic silica fine powder (BET 200 m ² / g) treated with dimethyldichlorosilane, hexamethyldisilazane, and dimethylsilicone oil Then, 0.05 parts by weight of styrene-acrylic fine particles (average particle size: 0.05 μm) obtained by soap-free polymerization were dry-mixed with a Henschel mixer to prepare Magnetic Toner (14) of the present invention. The void ratio of the magnetic toner (14) was 0.58.

Toner Production Examples 15 to 18 The resin composition (I) obtained in the above-mentioned resin composition production examples
I) to (V) and the magnetic toner of the present invention in the same manner as in Production Example 14 of the toner except that 100 parts by weight of each of the comparative resin composition (i) obtained in Comparative Production Example were used. (15) to (18) were prepared.

The magnetic toners (15) to (1) obtained above
Table 5 summarizes the prescription contents and various properties of 8).

[0338]

[Table 5]

[Production Example of Developing Sleeve and Comparative Production Example] A production example of a developing sleeve used in the image forming method of the invention will be described.

Developing sleeve production example 1 Resole type phenol resin solution (containing 50% methanol) 200 parts by weight Graphite (number average particle diameter 9 μm) 50 parts by weight Conductive carbon black 5 parts by weight Isopropyl alcohol 130 parts by weight

[0341] Zirconia beads having a diameter of 1 mm were added as media particles to the above materials, dispersed in a sand mill for 2 hours, and the beads were separated using a sieve to obtain a stock solution. Then, 380 parts of this stock solution was added to spherical PMMA particles (number average particle size 1).
2 μm) and isopropyl alcohol so that the solid content concentration becomes 30%.
The mixture was dispersed using glass beads of 1 mm for 1 hour, and the beads were separated using a sieve to obtain a coating liquid.

Using this coating solution, a coating layer was formed on an aluminum cylindrical tube having an outer diameter of 16 mmφ by a spray method, and then cured by heating at 150 ° C. for 30 minutes in a hot air drying furnace to produce a developing sleeve 1. did. Developing sleeve 1
Was Ra = 1.9 μm.

Developing Sleeve Manufacturing Example 2 In the developing sleeve manufacturing example 1, the spherical particles were replaced with spherical PMMs.
A developing sleeve 2 was prepared in the same manner as in the developing sleeve manufacturing example 1 except that the A particles (number average particle diameter 6 μm) were 15 parts by weight.
I got The Ra value of the obtained developing sleeve 2 is Ra = 1.
It was 4 μm.

Developing Sleeve Production Example 3 A developing sleeve 3 was obtained in the same manner as in the developing sleeve producing example 1 except that the spherical PMMA particles (number average particle diameter 4 μm) were changed to 5 parts by weight. The Ra value of the obtained sleeve 3 was Ra = 0.7 μm.

Developing Sleeve Manufacturing Example 4 In developing sleeve manufacturing example 1, an aluminum cylindrical tube subjected to sandblasting was used in order to make the surface roughness of the developing sleeve coating layer substantially equal to that of the developing sleeve 1, and spherical PMMA resin particles were further used. Developing sleeve 4 was obtained in the same manner as in Developing sleeve production example 1 except that was not added. The Ra value of the obtained developing sleeve 7 was Ra = 1.9 μm.
m.

[Examples and Comparative Examples] In this example, a commercially available laser beam printer LB was used.
P-PX and LBP-EX (both manufactured by Canon Inc.)
Was remodeled as shown below and used after resetting.

Examples 1 to 13 and Comparative Examples 1 to 5 LBP-PX was modified and used as an evaluation machine. That is,
In FIG. 4, a rubber roller (diameter: 12 mm, contact pressure: 50 g / cm) in which conductive carbon coated with a nylon resin is dispersed is used as the primary charging roller 11, and laser exposure (600 dpi) is performed on the electrostatic latent image carrier. ), A dark portion potential V _D = −600 V and a bright portion potential V _L = −150 V were formed.

Production Example 1 of Sleeve as Toner Carrier 16
Developing sleeve 1 is used, and then the exposure drum 10
(Diameter 24 mm) and the developing sleeve 1 (S-D
The gap was set to 300 μm, and a urethane rubber blade 18 having a thickness of 1.0 mm and a free length of 10 mm as a toner regulating member was brought into contact with the developing magnetic pole at 800 gauss at a linear pressure of 6 g / cm. DC bias component V _dc = -40 as a developing bias
0 V, a superimposed AC bias component V _pp = 1200 V, and a peripheral speed of 1800 Hz were used.

In the heating and fixing apparatus H, the surface temperature of the temperature measuring element 21d of the heating element 21 was 130 ° C., the total pressure between the heating element 21 and the pressure roller 23 was 6 kg, and the nip between the pressure roller and the film was 3 mm. As the fixing film 22, a heat-resistant polyimide film having a thickness of 50 μm and having a low-resistance release layer in which a conductive material is dispersed in PTEF on a contact surface with a transfer material was used.

Under the above set conditions, room temperature and normal humidity (25 ° C., 6
0% RH) and high-temperature and high-humidity (30 ° C., 80% RH) environment at a printout speed of 6 sheets (A4 size) / min. Magnetic toners (1) to (13) obtained in (1) to (7), and
A printout test in an intermittent mode (that is, a mode in which the developing unit is paused for 10 seconds each time one sheet is printed out and toner deterioration is promoted) while each of the comparative magnetic toners (25) to (31) is sequentially replenished. , And the obtained printout image was evaluated for the following items.

At the same time, the matching between the used image forming apparatus and the developer was evaluated.

At this time, in the evaluation of the fixing property, the magnetic toner (1) showed a very good low-temperature fixing property with an image reduction ratio before and after rubbing of 2%. Also, in the evaluation of the offset resistance, no image stain was generated, and excellent performance was exhibited.

The above evaluation results are summarized in Tables 6 and 7.

[0354]

[Table 6]

[0355]

[Table 7]

Examples 14 to 18 Using a modified LBP-EX as an evaluator, a rubber roller (diameter: 12 mm, contact pressure: 5 mm) in which conductive carbon coated with nylon resin was dispersed was used as a primary charging roller.
0 g / cm) using a dark portion potential V _D = -700 V, the light potential V _L = -200 V was formed by laser exposure (600 dpi) to the electrostatic latent image bearing member. The developing sleeve 4 of Sleeve Production Example 4 was used as the toner carrier, and then the gap between the photosensitive drum and the developing sleeve 4 (between SD)
Was set to 300 μm, and a urethane rubber blade having a thickness of 1.0 mm and a free length of 4 mm as a toner regulating member was brought into contact with the developing magnetic pole at 800 gauss at a linear pressure of 15 g / cm. DC bias component V _dc = -500 V, superimposed AC bias component V _pp = 1600 V, frequency 220 as development bias
0 Hz was used. The set temperature of the heat fixing device is 15
0 ° C.

Under the above set conditions, normal temperature and normal humidity (25 ° C., 6
0% RH) and a low temperature and low humidity (15 ° C., 10% RH) environment at a printout speed of 12 sheets (A4 size) / min. A printout test is performed in a continuous mode (that is, a mode in which the developing unit is continuously operated without stopping the developing device every time one sheet is printed out) while sequentially supplying each of (18), and the obtained printout image is described later. Items were evaluated.

At the same time, matching between the used image forming apparatus and the toner was also evaluated.

Table 8 summarizes the above evaluation results.

[0360]

[Table 8]

Examples 19 to 21 A print-out test was performed in the same manner as in Example 17 except that the developing sleeves were replaced with the developing sleeves 1 to 3 obtained in Production Examples 1 to 3 of the developing sleeve. The evaluation of the printout image obtained and the matching of the developing sleeve used were evaluated.

Table 9 summarizes the above evaluation results.

[0363]

[Table 9]

The evaluation items described in the examples of the present invention and the comparative examples and the evaluation criteria will be described.

[Evaluation of Printout Image] <1> Image Density The image density was evaluated by maintaining the image density when a predetermined number of printouts were completed on ordinary paper for copying machines (75 g / m ² ). The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth Co., Ltd.) with respect to a printout image of a white background portion having a document density of 0.00.

◎ (excellent): 1.40 or more, ○ (good): 1.35 or more, less than 1.40 Δ (acceptable): 1.00 or more, less than 1.35, × (impossible): 1.00 Less than

<2> Dot Reproducibility The checker pattern shown in FIG. 7 was printed out, and the dot reproducibility was evaluated.

◎: Very good (2 defects or less / 100) ○: Good (3 to 5/100 defects) Δ: Practical (6 to 10/100 defects) ×: Not practical (Lack 11 or more / 100)

<3> Image fog The fog density (%) was calculated from the difference between the whiteness of the white background portion of the printout image and the whiteness of the transfer paper measured by a “Reflectometer” (manufactured by Tokyo Denshoku Co., Ltd.). Image fog was evaluated.

◎: Very good (less than 1.5%) ：: Good (1.5% or more and less than 2.5%) Δ: Practical (2.5% or more and less than 4.0%) ×: Not practical (more than 4%)

<4> Sleeve Ghost Solid black band image X of width a and length 1 shown in FIG.
Are printed out, and the width b (>) shown in FIG.
When a halftone image Y having a length 1 is printed out in a), the grayscale difference appearing on the halftone image (FIG. 8)
(A), (B) and (C) in (c)) were visually evaluated.

A: very good (no shading difference is observed at all) o: good (a slight shading difference is observed between B and C) Δ: practical (a slight shading difference in each of A, B and C) ×: Not practical (a remarkable difference in shading is observed)

<5> Hollow-out The “surprise” character pattern shown in FIG.
g / m ² ) when printing characters (Fig. 9
(State (b)) was visually evaluated.

◎: very good (almost no occurrence) ：: good (slight) △: practicable ×: impractical (notable)

<6> Fixing Property The fixing property was evaluated by applying a load of 50 g / cm ² , rubbing the fixed image with soft thin paper, and decreasing the image density before and after rubbing (%).

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

<7> 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 after 3000 sheets.

◎: very good (not generated), ：: good (almost no occurrence) Δ: practical, ×: impractical

[Evaluation of Storage Stability] After the toner was left in a dryer set at 45 ° C. for one week,
A printout test was similarly performed on the left toner in a normal temperature and normal humidity environment, and the obtained image was evaluated from the image density and image quality.

[Evaluation of Matching of Image Forming Apparatus] <1> Matching with Developing Sleeve After completion of the printout test, the state of fixation of residual toner on the surface of the developing sleeve and the influence on the printout image were visually evaluated.

◎: Very good (not generated) ：: Good (almost no occurrence) Δ: Practical (there is sticking, but there is little effect on the image) ×: Practical not possible (a lot of sticking, uneven image) Produces

<2> Matching with Photosensitive Drum The occurrence of scratches on the surface of the photosensitive drum and sticking of residual toner and the effect on printout images were visually evaluated.

◎: very good (not generated) 良好: good (slight flaws are observed, but there is no effect on the image) Δ: practical (possible fixation or flaws, but the effect on the image is low) (Small), ×: impractical (many sticks, causing vertical streak-like image defects)

<3> Matching with Fixing Apparatus The appearance of the fixing film surface was observed and its durability was evaluated.

(1) Surface Properties After the completion of the printout test, the appearance of scratches and abrasion on the surface of the fixing film was visually evaluated.

◎: very good (not generated), ：: good (almost no occurrence) Δ: practical, ×: impractical

(2) Fixing Status of Residual Toner The fixing condition of the residual toner on the surface of the fixing film after completion of the printout test was visually evaluated.

◎: very good (not generated), ：: good (almost no occurrence) Δ: practical, ×: impractical

[0389]

As described above, according to the present invention,
After precisely controlling the composition of the inside and the outermost surface of the magnetic iron oxide particles containing the silicon element constituting the magnetic particle powder used in the magnetic toner, the surface of the magnetic iron oxide particles is subjected to a reactive surface modification. By applying a coating treatment with a chemical agent,
It is excellent in environmental stability and dot reproducibility, prevents image fogging and voids, and further prevents sleeve ghosts from occurring, and can form high-quality images for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an image forming apparatus used in the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a schematic explanatory view showing a configuration of a toner carrier used in the present invention.

FIG. 4 is a schematic explanatory view of an image forming apparatus used in an embodiment of the present invention.

FIG. 5 is an exploded perspective view of a main part of the fixing device used in the embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view of a main part showing a film state when the fixing device used in the embodiment of the present invention is not driven.

FIG. 7 is an explanatory diagram of a checker pattern for checking development characteristics of toner.

FIG. 8 is an explanatory diagram of a sleeve ghost.

FIG. 9 is a schematic diagram showing a state where a character image is hollow;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 toner carrier 2 particles 3 binder resin 4 conductive material 5 substrate 6 coating layer 30 image forming direction 100 photosensitive drum 102 developing sleeve (toner carrier) 103 contact blade 104 magnet roller 114 transfer charging roller 116 cleaner 117 primary Charging roller 140 Developing device 141 Stir bar

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI G03G 9/08 321 15/08 507L (56) References JP-A-7-72654 (JP, A) JP-A-6-194869 ( JP, A) JP-A-4-190242 (JP, A) JP-A-63-105901 (JP, A) JP-A-4-162051 (JP, A) JP-A-5-341561 (JP, A) JP Hei 6-83173 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (21)

(57) [Claims] 1. A magnetic toner for electrostatic image development containing at least a binder resin and magnetic particle powder, wherein the magnetic particle powder is coated with (a) a surface modifier having reactivity. (B) the magnetic iron oxide particles contain 0.4 to 2.0% by weight of silicon element (Si) based on iron element (Fe); (C) A magnetic toner for developing an electrostatic image, wherein the Fe / Si atomic ratio on the outermost surface of the magnetic iron oxide particles before the coating treatment is 1.0 to 4.0. 2. The magnetic iron oxide particles have a surface smoothness of 0.3.
The magnetic toner for developing an electrostatic image according to claim 1, wherein the number is from 8.0 to 8.0. 3. The magnetic iron oxide particles have a bulk density of 0.8 g /
The magnetic toner for developing an electrostatic image according to claim 1, wherein the magnetic toner is at least ³ cm ³ . 4. The magnetic iron oxide particles have a specific surface area of 15.0.
The magnetic toner for developing an electrostatic image according to claim 1, wherein the magnetic toner is at most m ² / g. 5. The magnetic iron oxide particles according to claim 1, wherein the magnetic iron oxide particles contain 0.01 to 2.0% by weight of an aluminum compound in terms of aluminum element (Al). The magnetic toner for developing an electrostatic image according to the above. 6. The static iron according to claim 1, wherein the Fe / Al atomic ratio at the outermost surface of the magnetic iron oxide particles before the coating treatment is 0.3 to 10.0. Magnetic toner for developing charge images. 7. A DSC curve having a volatile component of less than 0.1% by weight and having a maximum endothermic peak in a range of 70 to 130 ° C. at a temperature rise in a DSC curve measured by a differential scanning calorimeter, 7. The magnetic toner for developing an electrostatic image according to claim 1, further comprising a wax component having a maximum exothermic peak when the temperature falls within a range of ± 9 ° C. with respect to the peak temperature of the peak. 8. A main peak is formed in a region having a molecular weight of 2,000 to 30,000 in a molecular weight distribution of gel permeation chromatography (GPC) measured by a tetrahydrofuran (THF) soluble component of a binder resin in the toner. The electrostatic image development according to any one of claims 1 to 7, comprising a low molecular weight polymer component and a high molecular weight polymer component forming a subpeak or a shoulder in a region exceeding a molecular weight of 50,000. For magnetic toner. 9. The binder resin in the toner is substantially TH
In the molecular weight distribution of GPC containing no F-insoluble component and soluble in THF, the area ratio of the low molecular weight component having a molecular weight of 1000 or less is 15% or less and the area ratio of the high molecular weight component having a molecular weight of 1,000,000 or more. 9. The magnetic toner for developing an electrostatic image according to claim 1, wherein the ratio is 0.5 to 25%. 10. A high molecular weight component corresponding to a region having a molecular weight of 100,000 or more in a THF-soluble portion of a THF-soluble portion of a binder resin in the toner contains a polyfunctional polymerization initiator and / or a polyfunctional polymer. The magnetic toner for developing an electrostatic image according to claim 1, wherein the magnetic toner is a polymer component obtained by using an unsaturated monomer. 11. The wax component is represented by the following general formula: RY [R: a hydrocarbon group. Y represents a hydroxyl group, a carboxyl group, an alkyl ether group, an ester group, or a sulfonyl group. Having a weight average molecular weight of 300 by GPC
The magnetic toner for developing an electrostatic image according to any one of claims 1 to 10, further comprising 60% by weight or more of a compound of 0 or less. 12. A weight average diameter D ₄ (μm) of the toner.
Is 3.5 ≦ D ₄ ≦ 6.5, and the relationship with the abundance N (number%) of particles having a particle size of 3.17 μm or less in the number particle size distribution is as follows: 35−D ₄ × 5 ≦ N ≦ 180 2. A particle size distribution satisfying -D ₄ × 25.
12. The magnetic toner for developing an electrostatic charge image according to any one of items 11 to 11. 13. The magnetic toner according to claim 1, wherein the porosity of the toner is 0.5 to 0.7. 14. A charging step of applying a voltage to a charging member from the outside to charge a member to be charged, a step of forming an electrostatic image on the member to be charged, and a step of forming an electrostatic image by toner. A developing step of developing to form a toner image on the member to be charged, a transferring step of transferring the toner image on the member to be charged to the transfer material with or without the intermediate transfer member, and A fixing step of heating and fixing the toner image, wherein the toner contains at least a binder resin and magnetic particle powder, and the magnetic particle powder comprises: (a) a reactive surface modification agent; (B) the magnetic iron oxide particles comprise 0.4 to 2.0% by weight of silicon based on iron element (Fe); and it contains an element (Si), (c) the coating pretreatment The image forming method of Fe / Si atomic ratio in the outermost surface of magnetic iron oxide particles, characterized in that 1.0 to 4.0. 15. The heating and fixing step in which a toner image is heat-fixed to a recording material by a heating and fixing device that does not supply an offset preventing liquid or does not have a fixing device cleaner. 2. The image forming method according to 1., 16. The recording material according to claim 16, wherein said heating and fixing step comprises: a heating member fixed and supported; and a pressing member which is in pressure contact with said heating member and closely adheres to said heating member via a film. The image forming method according to claim 14, wherein the image is fixed by heating. 17. The method according to claim 14, wherein in the charging step, the charging member is brought into contact with the member to be charged, and a voltage is externally applied to the charging member to charge the member to be charged. 3. The image forming method according to 1., 18. A step of developing an electrostatic latent image on an electrostatic latent image carrier with a developer, and electrostatically transferring the developed image to a transfer material via a transfer device. 18. The image forming method according to claim 14, wherein the carrier and the transfer device are in contact with each other. 19. A developing method in which a coating layer containing conductive fine particles is formed on the surface of a developer carrying member that conveys to a developing region formed between the electrostatic latent image carrying member carrying toner on the surface. 14. The apparatus according to claim 14, wherein an apparatus is used.
9. The image forming method according to any one of 8. 20. The image forming method according to claim 14, wherein the coating layer contains particles for imparting roughness to the surface of the developer carrying member. 21. The image forming method according to claim 14, wherein the toner is the toner according to any one of claims 2 to 11.