JP2002341588A - toner - Google Patents

Abstract

(57) [Problem] To provide a toner which maintains high image quality and high image density even in long-term use, has excellent environmental stability, does not cause tailing, and consumes a small amount of toner. . A toner containing at least a binder resin, magnetic iron oxide, and an organometallic compound, wherein the organometallic compound has at least one alkyl group and two hydroxyl groups that can bind to an iron atom. An azo iron compound that can be produced from a monoazo compound having at least Z
n is contained in an amount of 0.1 to 4.0% by mass based on the magnetic iron oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in an image forming method such as an electrophotographic method, an electrostatic printing method, a magnetic recording method, and a toner jet method.

[0002]

2. Description of the Related Art JP-A-55-18656 (corresponding to U.S. Pat. Nos. 4,395,476 and 4,473,627).
In the specification, a jumping development method is 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 close to the electrostatic latent image.

In jumping development using magnetic toner, if the developing device is set so that the image density becomes sufficiently high, excessive toner is developed, resulting in deterioration of image quality and reduction of toner consumption. There is a problem that it increases or the tailing deteriorates.

In order to reduce the amount of toner consumed, a combination of a charge control agent having a function of enhancing the chargeability of the toner and a magnetic material exposed to the surface of the toner particles and acting as a leak site of the charge is highly used. Control the amount,
It is important to control the standing of the toner on the sleeve.

Conventionally, magnetic iron oxides contained in magnetic toners are disclosed in JP-A-62-279352 (corresponding to US Pat. No. 4,820,603) and JP-A-62-227.
No. 8131 (corresponding US Pat. No. 4,975,214) proposes a magnetic toner containing magnetic iron oxide particles containing a silicon element. Such magnetic iron oxide particles positively have a silicon element present inside the magnetic iron oxide particles. However, in a magnetic toner containing the magnetic iron oxide particles, improvements such as a decrease in developability during long-term use are made. Have points to do.

[0006] JP-A-4-362954 (corresponding European Patent Application Publication No. EP-A468525),
JP-A-281778 discloses magnetic iron oxide particles containing both a silicon element and an aluminum element. However, such magnetic iron oxide particles have been improved in long-term use in a high-temperature, high-humidity environment, such as a decrease in developability and a deterioration in toner consumption. Have the point to be.

JP-A-9-59024 and JP-A-9-590
Japanese Unexamined Patent Publication No. 59025 discloses that the ratio of Fe to Si is 1.7
And at least one metal element selected from Mn, Zn, Ni, Cu, Al and Ti as a metal element other than iron containing 0 to 4.5 atomic% of silicon in an amount of 0 to 10 atoms with respect to Fe. % Of magnetite particles.

As a result, the magnetic properties are improved, and the chargeability can be improved. However, the mere addition of the metal does not reduce the toner consumption.
It has further points to be improved.

Japanese Patent Application Laid-Open No. 11-157843 discloses that Zn, Mn, Cu, which contain a silicon component continuously from the center of the magnetite particle to the surface, expose the silicon component on the particle surface, and combine with the silicon component. Ni, Co, Cr, C
d, Al, Sn, Mg, magnetite particles in which the particle outer shell is coated with a metal compound comprising at least one or more metal components selected from among Ti are disclosed,
The image quality and developability in long-term use, the toner consumption, and the tailing have not been sufficiently improved.
It has further points to be improved.

JP-A-11-316474, JP-A-11-249335 and JP-A-11-28220
No. 1 discloses Mn, Zn, N based on the iron element.
i, Cu, Co, Cr, Cd, Al, Sn and Mg, the content of at least one metal element selected from the group consisting of the silicon element content, and the iron element dissolution rate of up to 20% by mass. There is disclosed a magnetic iron oxide in which the content ratio of a silicon element and the content ratio of a silicon element existing up to an iron element dissolution rate of 10% are specified.

As described above, by including various metals in the magnetic iron oxide and defining the distribution of Si in the magnetic iron oxide, the effect of improving the environmental stability can be seen, but the reduction in toner consumption can be achieved. Further improvement is desired.

JP-A-11-189420 discloses that a magnetite particle contains a silicon component and an aluminum component continuously from the center to the surface of the magnetite particle, and these components are exposed on the surface of the particle and combined with the silicon component and the aluminum component. Zn, Mn, Cu, Ni, Co, Cr, Cd, Al, S
Although magnetite particles whose outer shell is coated with a metal compound comprising at least one or more metal components selected from n, Mg, and Ti have been disclosed, it is still necessary to impart sufficient charge stability to the magnetic toner. Has not been reached.

JP-A-4-184354 and JP-A-Hei.
Japanese Unexamined Patent Publication No. 223487/1992 discloses a method of reducing the saturation magnetization of a toner by replacing divalent iron of magnetite with a divalent metal such as zinc or copper. Control alone is not sufficient to achieve toner charging stability and reduction in consumption.

On the other hand, many metal complexes having an azo dye structure used as charge control agents for toner generally have poor stability, such as mechanical friction and impact, changes in temperature and humidity conditions, electrical shock, and light irradiation. The initial charge controllability tends to be lost due to decomposition or change due to the above. In addition, even if it has a practical level of charge imparting property, there is a problem with the stability of the charge, and it often contains impurity chemical substances that do not have a charge control effect due to the difference in manufacturing method, and the quality stability And various problems such as reliability.

JP-A-2-35465, JP-B-7-35
The metal complex salt compounds of monoazo dyes disclosed in JP-A-27283 and JP-A-9-169919 are excellent from the viewpoint of imparting triboelectricity, but are stable irrespective of environmental fluctuations, aging and use conditions. It has not yet been developed.

The amorphous metal complex disclosed in Japanese Patent Application Laid-Open No. 11-7164 is excellent in dispersibility and chargeability in a toner. In some cases, the toner is susceptible to impact, and the use of the toner for a long period of time causes the deterioration of the toner to gradually reduce the developing property.

[0017]

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

That is, an object of the present invention is to provide a toner which maintains high image quality and high image density even after long-term use, has excellent environmental stability, does not cause tailing, and consumes a small amount of toner. It is in.

[0019]

According to the present invention, there is provided a toner containing at least a binder resin, a magnetic iron oxide and an organometallic compound, wherein the organometallic compound contains one or more alkyl groups, an iron atom and An azo iron compound which can be produced from a monoazo compound having two bondable hydroxyl groups, wherein the magnetic iron oxide contains at least 0.1 to 4.0% by mass of Zn based on the magnetic iron oxide. The present invention relates to a characteristic toner.

[0020]

DETAILED DESCRIPTION OF THE INVENTION It has been found that the combination of a charge control agent and magnetic iron oxide has a very large effect on the developability of a magnetic toner using magnetic iron oxide. The charge control agent is designed to give a high charge amount to the toner instantaneously, whereas the magnetic iron oxide is exposed on the surface of the toner particles and acts as a charge leak site. This is because the performance of the toner greatly changes depending on the combination of the two materials.

In the conventional toner, if the developing device is set so that a sufficiently high image density can be obtained for an image such as solid black, excessive toner is developed in the image portion, and the line width becomes large. The amount tended to increase. Further, if excessive toner is developed, there is a problem that image quality and tailing are likely to deteriorate.

Conversely, if the developing device is set so as to reduce the toner consumption, the image density tends to be low and the line width tends to be narrow, and tailing is suppressed only by improving the developing device. On the other hand, it is difficult to achieve high image quality while satisfying high image density and low toner consumption, and satisfying all of these characteristics largely depends on toner performance.

The inventors of the present invention have studied to suppress tailing and reduce toner consumption while maintaining a high image quality and a sufficiently high image density. As a result, a specific organometallic compound and a magnetic iron oxide were combined. As a result, it has been found that tailing can be suppressed and toner consumption can be reduced while maintaining high developability and image quality regardless of the use environment.

The reason that the toner consumption is reduced is that the toner of the related art has more toner than the minimum necessary for forming an image on the image portion, whereas the toner of the present invention has an appropriate amount. It is because it became quantity.

The reason why the toner of the present invention can reduce the amount of consumed toner as compared with the conventional toner is considered as follows.

In the jumping development method using a magnetic toner, the toner is in a state where ears are formed on a sleeve.
At the time of development, it flies in the form of ears on the electrostatic charge image on the photoconductor. If the ears are thick or long, the toner is developed on the photoreceptor as a large aggregate,
Development unevenness easily occurs, and a large amount of toner is required to completely cover the electrostatic charge image of a certain area (obtain a high image density).

When the ears are thick or long, when a pattern of minute dots such as a halftone image is output, the ears are likely to protrude into a non-image portion of the electrostatic charge image on the photosensitive member, and the resolution is low. In some cases, a rough image may be generated in a reduced or halftone image. In addition, tailing is a phenomenon in which a toner image explodes at the fixing nip portion and scatters downstream in the transfer material transport direction, and when heated in the fixing nip portion, a steam flow is rapidly generated from a recording material such as paper. However, this is caused by the toner being blown off, and is likely to occur when a line image such as a horizontal line is developed with a high line height or when the developed toner has a low charge amount.

Further, if the line image is developed with a high line height, the image is crushed by the pressure at the fixing nip portion during fixing, so that the line width becomes large and minute dots cannot be reproduced. In some cases, resulting in a decrease in image quality.

When the organometallic compound used in the present invention and the magnetic iron oxide containing Zn are combined, the magnetic force acting between the toner particles and the electrostatic force are highly balanced, and thin and short ears are densely formed on the sleeve. Becomes possible. As a result, the electrostatic charge image on the photoreceptor can be uniformly covered with the minimum necessary amount of toner, and a high image density can be obtained with a small amount of toner. This means that the image density of solid black or the like is kept high, the line is not thinned in the line image portion, and the height of the developed toner image is low. Therefore, minute dots can be faithfully reproduced, and image quality is improved. Further, even if water vapor or the like is generated from the transfer material in the fixing nip portion, the toner image is less likely to be disturbed, and tailing is suppressed.

The toner of the present invention has a charge controlling agent which has excellent dispersibility in the toner and has a high charging ability, and has a function of leaking when the charging becomes excessive. By using a magnetic iron oxide that constantly functions to maintain a constant value regardless of the environment, a toner having a high charge amount and a sharp charge amount distribution can be obtained regardless of the use environment. Further, since the magnetic iron oxide has good adhesion to the binder resin and excellent dispersibility in the toner, the magnetic force between the toner particles can be controlled to a high degree.

As a result, the toner particles can form fine and short spikes densely on the sleeve, and a high image density and a high quality image can be obtained with a small amount of toner consumption while suppressing tailing. . Furthermore, since there is little fluctuation in the charging environment, high image density can be stably obtained over a long period of time even in a high-temperature high-humidity environment or a low-temperature low-humidity environment.

The organometallic compound, which is one of the means for achieving the present invention, comprises one or more alkyl groups and two or more alkyl groups capable of binding to iron.
An azo iron compound that can be produced from a monoazo compound having one hydroxyl group.

Since the azo iron compound used in the present invention has an alkyl group, it has good compatibility with the binder resin, has good dispersibility in the toner, and can have a uniform charge amount distribution of the toner. In addition, the toner can be provided with a stable rise of charge and good developability.

Further, the developing performance in the latter half of the durability caused by poor dispersion of the monoazo compound in the toner caused when the toner is used in a durable manner is not caused. Can bring.

The azo iron compound of the present invention is preferably crystalline. By being crystalline, the electronic state of the azo iron compound is easily stabilized, and high charge can be imparted to the toner regardless of the use environment. In addition, when it is crystalline, impurities are less likely to be contained in the crystal, so that the purity of the azo iron compound can be increased, and the triboelectric chargeability of the toner can be improved with a small amount of addition.
Further, since impurities do not affect the developability, the amount of addition can be increased, and higher triboelectrification can be imparted.

Conventionally, when a crystalline azo iron compound was used in a toner, there was a problem that the photoreceptor was damaged due to its hardness, and the toner was easily dropped off from the surface of the toner particles. Since it has a group, it has a high affinity with the binder resin and is hardly detached from the toner surface. Also,
Because of the high affinity with the binder resin, it is easy to disperse uniformly in the toner, so it is difficult to be crushed at the interface between the binder resin and the azo iron compound in the pulverization process when forming the toner, and the azo iron compound is Since the local exposure can be suppressed, the photoconductor is not damaged.

Whether the azo iron compound is crystalline can be confirmed by analyzing the X-ray diffraction spectrum of the azo iron compound. To indicate that the X-ray diffraction spectrum is crystalline means that the X-ray diffraction pattern shows a prominent diffraction peak as shown in FIG. Specifically, 2θ
= Ratio of the total intensity of the crystal part to the total intensity calculated by the multiple peak separation method for the X-ray diffraction spectrum of the azo iron compound in the range of 10 ° to 20 ° (θ is the Bragg angle) (crystallinity) Has a crystallinity of more than 60% is defined as "crystalline" in the present invention.

Whether the azo iron compound of the present invention is crystalline as defined in the present invention can be measured, for example, under the following conditions.

[0039] The azo iron compound, for example, by X-ray diffraction device MXP ³ system Ltd. Mac Science Co., measuring the X-ray diffraction spectrum by CuKα-ray.
The spectrum obtained by smoothing the X-ray diffraction spectrum in the range of 2θ = 10 ° to 20 ° (θ is the Bragg angle) is further separated into the entire spectrum and the spectrum of the crystal part. For each spectrum of the separated chart, the total sum of the intensities and the sum of the intensities of the crystal parts were determined by the crystallinity measurement method in the range of 2θ = 10 ° to 20 ° (θ is the Bragg angle), and the following formula was used. Calculate the crystallinity. In particular, when the crystallinity is high and the number of peaks is large, the range of 2θ may be subdivided every 5 °, the crystallinity may be obtained in each range, and then the average value of each range may be obtained. Crystallinity (%) = (total strength of crystal part / total strength of whole) × 100

The effect of crystallinity increases as the degree of crystallinity increases, and in order to obtain better durability, the degree of crystallinity must be 70%.
More preferably, it is more preferably 80% or more.

The monoazo compound capable of forming an azo iron compound in the present invention is a compound represented by the formula (a), (b) or (c) in order to stabilize developability such as image density and fog. Preferred.

[0042]

Embedded image (In the formula, R _{1 to} R ₈ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{1 to} R ₈ is an alkyl group.)

[0043]

Embedded image (In the formula, R _{9 to} R ₁₈ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{9 to} R ₁₈ is an alkyl group.)

[0044]

Embedded image (In the formula, R _{19 to} R ₃₀ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{19 to} R ₃₀ is an alkyl group.)

Further, each monoazo compound, as long as it has at least one alkyl group in the molecule as a substituent, the position of the alkyl group is not particularly limited, R ₁₃ in formula (b) to R Having an alkyl group at the position ₁₈ is particularly preferred from the viewpoint of imparting stable chargeability to the toner.

Among the above monoazo compounds, monoazo compounds having an alkyl group having 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms as a substituent, can provide a high charge amount and a sharp charge amount distribution, and provide high image density and high image density. It is preferable to achieve both low toner consumption. Further, the image quality is improved, and tailing is suppressed. A monoazo compound having an alkyl group having 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms as a substituent, has improved compatibility with the binder resin in the toner due to the action of the alkyl group, thereby stabilizing the chargeability of the toner. . More preferably, it is a monoazo compound having a tertiary alkyl group having 4 to 12 carbon atoms as a substituent, and further preferably, a monoazo compound having 6 to 1 carbon atoms.
In the case of a monoazo compound having a tertiary alkyl group of 0 as a substituent, the charge retention ability is increased, the change with the lapse of time is reduced, and the toner can be more uniformly dispersed in the toner. Becomes more uniform. It is also preferable to have one or more halogen atoms as substituents together with the alkyl group in terms of stabilizing the charge distribution in the compound.

The following are specific examples of the monoazo compound preferably used in the present invention.

[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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The azo iron compound used in the present invention is a reaction product of iron and a monoazo compound, and is an azo iron compound in which the above monoazo compound is coordinated to an iron atom. The azo iron compound is an iron complex, an iron complex salt, or a mixture thereof, preferably an azo iron compound selected from the azo iron compounds represented by the general formulas (d), (e), and (f) or a mixture thereof. .

[0058]

Embedded image (In the formulas (d), (e) and (f), A and B each independently represent o-phenylene or 1,2-naphthylene;
At least one of A and B has one or more alkyl groups. A and B each may further have a halogen atom as a substituent. M is a cation and represents a hydrogen ion, an alkali metal ion, an ammonium ion, or an organic ammonium ion. )

In the present invention, since the monoazo compound having an alkyl group and iron react with each other, the compound becomes more stable thermally and with time as compared with the case where another metal is used. Performance can be imparted.

The azo iron compound used in the present invention can be obtained by reacting a monoazo compound capable of binding to an iron atom with an ironing agent in water and / or an organic solvent (preferably in an organic solvent). .

In general, the reaction product obtained in an organic solvent can be taken out by filtering and washing with water, or by dispersing in an appropriate amount of water, filtering the precipitate, washing with water, and drying. In order to reduce impurities, it is preferable to filter directly from an organic solvent, wash with water and dry.

Examples of the organic solvent used for such an ironation reaction include methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and ethylene glycol dimethyl ether (monoglyme). , Diethylene glycol dimethyl ether (diglyme), ethylene glycol diethyl ether, triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme),
Alcohol, ether and glycol organic solvents such as ethylene glycol and propylene glycol;
Water-soluble organic solvents such as aprotic polar solvents such as N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide can be mentioned. Preferred as the organic solvent are isopropanol, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), and ethylene glycol, which reduce impurities or synthesize a crystalline azo iron compound. It is preferred in that respect.
It is particularly preferable to recrystallize the azo iron compound obtained in another solvent in the above-mentioned organic solvent in order to enhance the crystallinity.

The amount of the organic solvent to be used is not particularly limited, but is 2 to 5 times the mass of the above-mentioned monoazo compound used as a ligand.

Examples of the above-mentioned ironing agents that are suitable include ferric chloride, ferric sulfate, and ferric nitrate. The ironing agent is generally used in an amount of 1/3 to 2 equivalents, preferably 1/2 to 2/3 equivalents in terms of an iron atom equivalent per 1 mol of the monoazo compound serving as a ligand.

The preferred amount of the azo iron compound to be added to the toner in the present invention is in the range of 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the binder resin. Can be

The compound of the present invention can be used in combination with a known charge control agent. For example, other organometallic complexes, metal salts, chelate compounds, specifically, monoazo metal complexes, acetylacetone metal complexes,
Examples thereof include a hydroxycarboxylic acid metal complex, a polycarboxylic acid metal complex, and a polyol metal complex. Other examples include metal salts of carboxylic acids, carboxylic acid derivatives such as carboxylic anhydrides and esters, and condensates of aromatic compounds. In addition, phenol derivatives such as bisphenols and calixarenes are also exemplified.

The magnetic iron oxide used in the toner of the present invention contains at least Zn in an amount of 0.1 to 4.0 based on the magnetic iron oxide.
0% by mass, preferably 0.1 to 2.0% by mass, more preferably 0.2 to 2.0% by mass, and still more preferably 0.2 to 1.0% by mass. , The Zn content B _Zn present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by mass, and the Z content present in the magnetic iron oxide.
The ratio of the total content A _Zn of _{n (B Zn / A Zn)} × 100 is 40
It is preferably from 100% to 100%.

The magnetic iron oxide containing Zn has an excellent balance of surface condition, electric resistance, exposure condition to the toner particle surface, etc., and controls the toner to have high charge and narrow the distribution of the charge amount. The above effect is effectively exhibited when combined with the above-mentioned azo iron compound. as a result,
Fine and short spikes can be densely formed on the sleeve, and high image quality and low toner consumption can be achieved at the same time with high image quality. It is more preferable that Zn be present in the vicinity of the surface of the magnetic iron oxide in a large amount, since the effect of the combination with the azo iron compound is enhanced.

If the Zn content is less than 0.1% by mass, the magnetic iron oxide is less likely to be exposed on the surface of the toner particles. In particular, when the toner is excessively charged, it leaks and the function of properly maintaining the charge amount is weakened. In a low-temperature and low-humidity environment, the charge-up causes a decrease in density and an increase in fog. If the Zn content is more than 4.0% by mass, the adhesiveness between the binder resin and the magnetic iron oxide becomes weak, so that the magnetic iron oxide exposed on the toner particle surface is easily released from the toner particles by long-term use. In a high-temperature and high-humidity environment, the charge amount decreases, and the image density decreases.

(B _Zn / A _Zn ) × 100 is 40 to 100%
In this case, since the dispersion of the magnetic force between the toner particles is reduced, thin and short ears can be densely formed on the sleeve, and it is easy to balance high image density and low toner consumption.
Further, even if the image density is set to be high, the image quality and the tailing hardly deteriorate.

In the present invention, the magnetic iron oxide preferably contains 0.1 to 2.0% by mass of Si based on the magnetic iron oxide.
Is more preferably 0.01 to 0.5% by mass based on the magnetic iron oxide.

Further, Si present on the surface of the magnetic iron oxide
It is preferable that the ratio (S _Si / T _Si ) × 100 between the content S _Si and the total content T _{Si of} Si present in the magnetic iron oxide is 10 to 55%.

Further, the iron dissolution rate of the magnetic iron oxide is 20
% Of Si present up to% _SiAnd in the magnetic iron oxide
Total content T of Si present in_SiAnd the ratio (B_Si/ T_Si) ×
Preferably, 100 is 40 to 90%.

The simultaneous presence of Zn and Si in the magnetic iron oxide makes it easier to balance the hygroscopicity and the electric resistance of the magnetic iron oxide, and easily obtains the function of controlling the charge amount of the toner. In particular, when the Si content of the magnetic iron oxide is 0.1 to 2.0% by mass, it is easy to balance image density and toner consumption, and the developability in a high-temperature and high-humidity environment is excellent.

When the content of Si present on the surface of the magnetic iron oxide is 0.01 to 0.5% by mass, the toner excellently functions as a leak site when the charge of the toner becomes excessively high, and can be used in a low temperature and low humidity environment. Is prevented, the reduction in image density and the increase in fog are suppressed. Also, the adhesion between the binder resin and the magnetic iron oxide is improved, free magnetic iron oxide is less likely to be generated, and the developability in a high-temperature, high-humidity environment is hardly deteriorated.

When (S _Si / T _Si ) × 100 is 10 to 55%, it is easy to control the charge amount of the toner, so that a toner having a high charge amount and a sharp charge amount distribution can be obtained. High developability can be obtained even in an environment or a high-temperature, high-humidity environment. In addition, the magnetic force acting between the toner particles is well balanced, and thin and short ears can be densely formed on the sleeve. As a result, image quality is improved, high image density is easily balanced with low toner consumption, and tailing is suppressed.

(B_Si/ T_Si) X 100 is 40-90%
If there is, there will be a lot of Si on the surface of the magnetic iron oxide.
The electrical resistance and moisture absorption of magnetic iron oxide in combination with Zn
Controllability to a high degree, and excellent developability
can get. Also, (B_Si/ T _Si) × 100 falls within this range
If there is, the surface of the magnetic iron oxide will have moderate irregularities and bind
Exposed on the surface of toner particles because it can improve the adhesion to fat
Magnetic iron oxide particles are less likely to be released,
However, the developability is hardly deteriorated.

Next, the structure and production method of the magnetic iron oxide used in the present invention will be described.

The magnetic iron oxide according to the present invention is produced, for example, by the following method. After adding a predetermined amount of Zn metal salt and silicate to the aqueous ferrous salt solution, an alkali such as sodium hydroxide is added to the iron component in an equivalent amount or more to prepare an aqueous solution containing ferrous hydroxide. I do. PH of prepared aqueous solution
While maintaining the pH at or above 7 (preferably from pH 8 to 10), air is blown in, and while the aqueous solution is heated to at least 70 ° C., an oxidation reaction of ferrous hydroxide is performed to form a seed crystal serving as a core of magnetic iron oxide particles. Generate first.

Next, an aqueous solution containing the first equivalent of ferrous sulfate based on the previously added alkali is added to the slurry-like liquid containing the seed crystals. The reaction of ferrous hydroxide is promoted while blowing air while maintaining the pH of the solution at 6 to 10, and magnetic iron oxide particles are grown around the seed crystal. The pH of the solution shifts to the acidic side as the oxidation reaction proceeds, but it is preferable that the pH of the solution is not less than 6. By adjusting the pH of the solution at the end of the oxidation reaction, it is preferable that the Zn or Si compound is unevenly distributed on the surface of the magnetic iron oxide particles by a predetermined amount. At this time, if a metal salt, silicate, or the like of Zn is added, various metals can be present in the vicinity of the surface of the magnetic iron oxide.

As metal salts other than iron used for the addition, sulfates, nitrates and chlorides can be used. Examples of the silicate that can be used for addition include sodium silicate and potassium silicate.

As the ferrous salt, iron sulfate which is generally produced as a by-product in the production of titanium sulfate, iron sulfate which is produced as a result of washing the surface of a copper plate, and iron chloride and the like can be used. .

The method for producing magnetic iron oxide by the aqueous solution method generally uses an iron concentration of 0.5 to 2 mol / liter based on the prevention of an increase in viscosity during the reaction and the solubility of iron sulfate. Generally, the lower the concentration of iron sulfate, the smaller the particle size of the product tends to be. At the time of the reaction, the larger the amount of air and the lower the reaction temperature, the more easily the particles are atomized.

According to the above-mentioned production method, when observed by a transmission electron microscope photograph, the magnetic iron oxide particles are mainly composed of spherical particles formed of a curved surface having no plate-like surface, and contain almost no octahedral particles. It is preferable to form a magnetic iron oxide and use the magnetic iron oxide in a toner.

In the present invention, the magnetic iron oxide particles preferably have a bulk density of 0.5 to 0.9 g / cm ³ , more preferably 0.6 to 0.8, based on a measuring method described later.
g / cm ³ should be satisfied. Bulk density 0.5g /
If the particle size is less than ³ cm ³ , the toner may have an adverse effect on the physical miscibility with other constituent materials during the production of the toner, and the dispersibility of the magnetic iron oxide in the toner may be deteriorated. Further, when the bulk density exceeds 0.9 g / cm ³ , when the magnetic toner is used, the toner tends to be tight in a developing device, and the fluidity of the toner may be reduced to cause fading.

In the present invention, the magnetic iron oxide has a number average particle diameter based on a measuring method described below, preferably 0.05%.
To 1.00 μm, more preferably 0.10 to 0.4
The thickness of 0 μm is good in terms of the dispersibility of the magnetic toner in the binder resin and the uniformity of charging.

In the present invention, the magnetic iron oxide has a BET specific surface area of ² to 40 m ² / g based on a measuring method described later,
Preferably, those having 4 to ²⁰ m ² / g are preferably used.

In the present invention, the magnetic iron oxide has a saturation magnetization of 10 to 10 under a magnetic field of 795.8 kA / m.
200 Am ² / kg, more preferably 70-100 Am ²
/ Kg, residual magnetization is 1 to 100 Am ² / kg, more preferably ^{2 to 20} Am ² / kg, and coercive force is 1 to 30 kA / kg.
m, more preferably 2 to 15 kA / m. By having such magnetic properties,
The magnetic toner can obtain good developability with a balance between image density and fog.

In the present invention, the magnetic toner is preferably prepared by adding magnetic iron oxide particles to 100 parts by mass of the binder resin.
20 to 200 parts by mass, more preferably 30 to 150 parts by mass
It is good to contain by mass. When the content of the magnetic iron oxide is less than 20 parts by mass, the transportability is insufficient, and the developer layer on the developer carrier may be uneven, resulting in image unevenness. When the content of the magnetic iron oxide exceeds 200 parts by mass, the image density may decrease.

In the present invention, the magnetic iron oxide particles may be treated with a surface treating agent such as a silane coupling agent, a titanium coupling agent, titanate, aminosilane or an organosilicon compound.

The method for measuring various physical property data in the present invention will be described in detail below.

(1) Determination of the amount of metal elements present in magnetic iron oxide In the present invention, the content of metal elements other than iron in magnetic iron oxide (based on magnetic iron oxide) and the dissolution rate of iron element The content of the metal element other than iron with respect to the iron element dissolution rate can be determined by the following method. For example, about 3 liters of deionized water is placed in a 5 liter beaker and heated in a water bath to 45 to 50 ° C. About 25 g of magnetic iron oxide slurried with about 400 ml of deionized water is added to the 5 liter beaker with the deionized water while washing with about 300 ml of deionized water.

Next, while maintaining the temperature at about 50 ° C. and the stirring speed at about 200 rpm, a special grade hydrochloric acid or a mixed acid of hydrochloric acid and hydrofluoric acid is added to start dissolution. At this time, the hydrochloric acid aqueous solution is adjusted to about 3 mol / liter. Approximately 2
Sample 0 ml, filter through a 0.1 μm membrane filter, and collect the filtrate. The filtrate is subjected to plasma emission spectroscopy (ICP) to quantify iron elements and metal elements other than iron elements.

The dissolution rate of iron element is calculated by the following equation. Iron element dissolution rate (% by mass) = (a / b) × 100 a: Iron element concentration in the collected sample (mg / l) b: Iron element concentration when completely dissolved (mg / l)

The content of metal elements other than iron based on magnetic iron oxide is calculated by the following equation. Metal element content (% by mass) based on magnetic iron oxide = ((c × d) / (e × 1000)) × 100 c: Metal element concentration (mg / l) d in the collected sample : Sample amount collected (l) e: Mass of magnetic iron oxide (g)

The dissolution rate of each metal element is calculated by the following equation. Metal element dissolution rate (%) = (f / g) × 100 f: Content rate of metal element in each iron element dissolution rate (% by mass) g: Content rate of metal element when completely dissolved (% by mass)

The dissolution rate of each metal element existing when the dissolution rate of the iron element of the magnetic iron oxide is up to 20% by mass is determined as follows.

The time when the dissolution rate of the iron element reached 100% by mass was used as a reference, and the time required for the dissolution rate of the iron element to reach 20% by mass was calculated therefrom. Several samples corresponding to the iron element dissolution rate of 20% by mass were selected from the samples, and the Si content B _Si existing when the iron element dissolution rate was up to 20% by mass and the total content of Si present in the magnetic iron oxide. ratio of T _Si, and Zn total content a of the content B _Zn and Zn present in the magnetic iron oxide
The ratio with respect to _Zn (dissolution rate of each element) is calculated or calculated.

(2) Determination of Si existing on the surface of magnetic iron oxide 0.9 g of magnetic iron oxide is precisely weighed and put into a beaker. Next, 25 ml of 1 mol / liter-NaOH is weighed and put into a beaker.

The rotor was put in a beaker, covered, heated and stirred (liquid temperature 70 ° C.) for 4 hours on a hot stirrer, and allowed to cool. After cooling, all the magnetic iron oxides including the magnetic iron oxide attached to the rotor are poured into the measuring cylinder with pure water. After adjusting to 125 ml with pure water, transfer to a beaker and stir well.

Thereafter, the beaker is allowed to stand on the magnet, and the magnetic iron oxide is settled until the supernatant becomes transparent. After settling,
The supernatant is filtered, and the filtrate is put into a sample bottle and ICP
Analyze with.

The surface Si (% by mass) is calculated by the following equation. Surface Si (% by mass) = (L × 0.125) / (S × 10
00) × 100 L: ICP measurement value (mg / l) S: Sample mass (g)

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

(4) Number-average particle size of magnetic iron oxide 100 particles were randomly selected from a transmission electron micrograph (magnification: 30,000), the particle size was measured, and the average value was used as the number-average particle size. Diameter.

(5) Specific surface area of magnetic iron oxide Specific surface area measuring device Autosoap 1 according to the BET method
Nitrogen gas is adsorbed on the surface of the sample using (Yuasa Ionics) and the specific surface area can be calculated using the BET multipoint method.

(6) Magnetic Properties of Magnetic Iron Oxide The magnetic properties can be measured using an "oscillating sample magnetometer VSM-3S-15" (manufactured by Toei Kogyo Co., Ltd.) under an external magnetic field of 795.8 kA / m.

The types of binder resins used in the present invention include styrene resins, styrene copolymer resins, polyester resins, polyol resins, polyvinyl chloride resins, phenol resins, naturally modified phenol resins, and naturally modified male resins. Acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, cumarone indene resin, petroleum-based resin, A polyester resin or a styrene-based copolymer resin which has a small change in the environment of the chargeability and is excellent in fixability is preferably used.

Examples of comonomers for the styrene monomer of the styrene copolymer include styrene derivatives such as vinyltoluene, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, and acrylate 2- Acrylates such as ethylhexyl and phenyl acrylate; methacrylates such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate and octyl methacrylate; maleic acid; butyl maleate, methyl maleate and dimethyl maleate Dicarboxylic acid esters having a double bond such as: acrylamide, acrylonitrile, methacrylonitrile, butadiene; vinyl chloride; vinyl esters such as vinyl acetate and vinyl benzoate; ethylene and propylene Emissions, such as ethylene-based olefin butylene; vinyl methyl ketone, such as vinyl vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl propionate ether. These vinyl monomers are used alone or in combination of two or more.

The binder resin in the present invention may have an acid value. Examples of the monomer for adjusting the acid value of the binder resin include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, cinnamic acid, vinyl acetic acid, isocrotonic acid, and angelic acid;
Alternatively, β-alkyl derivatives, fumaric acid, maleic acid, citraconic acid, alkenyl succinic acid, itaconic acid, mesaconic acid, dimethyl maleic acid, unsaturated dicarboxylic acids such as dimethyl fumaric acid and monoester derivatives or anhydrides thereof, Such a monomer can be used alone or as a mixture and copolymerized with another monomer to produce a desired polymer. Among them, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid for controlling the acid value.

More specifically, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate,
Monoesters of α, β-unsaturated dicarboxylic acids such as monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate, etc .; monobutyl n-butenylsuccinate, monomethyl n-octenylsuccinate, Monoesters of alkenyldicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenylglutarate, monobutyl n-butenyladipate, and the like are included.

The carboxyl group-containing monomer as described above may be added in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, based on 100 parts by mass of all the monomers constituting the binder resin.

The resin composition according to the present invention has a glass transition temperature (Tg) of 45 to 80 ° C., preferably 50 to 70 ° C. from the viewpoint of storage stability. Causes deterioration of the toner and offset at the time of fixing. If the Tg exceeds 80 ° C., the fixability tends to decrease.

The polymerization method which can be used in the present invention as a method for synthesizing the binder resin of the present invention includes a solution polymerization method, an emulsion polymerization method and a suspension polymerization method.

Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. . In this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer)
And the aqueous phase are separate, so that the termination reaction rate is low, resulting in a high polymerization rate and a high degree of polymerization. Further, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
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 an operation such as salting out is required to take out the polymer. To avoid this inconvenience, suspension polymerization is advantageous.

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

The binder resin used in the present invention is preferably formed by using a polyfunctional polymerization initiator alone or in combination with a monofunctional polymerization initiator as exemplified below.

Specific examples of the polyfunctional polymerization initiator having a polyfunctional structure include 1,1-di-t-butylperoxy-
3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxyisopropyl) benzene,
2,5-dimethyl-2,5- (t-butylperoxy)
Hexane, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, tris- (t-butylperoxy) triazine, 1,1-di-t-butylperoxycyclohexane, 2,2 -Di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate , Di-t-butylperoxytrimethyladipate, 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-t-
Polyfunctional polymerization initiator having a functional group having a polymerization initiation function such as two or more peroxide groups in one molecule such as butylperoxyoctane and various polymer oxides,
And a functional group having a polymerization initiating function such as a peroxide group in one molecule such as diallyl peroxydicarbonate, t-butyl peroxymaleic acid, t-butyl peroxyallyl carbonate and t-butyl peroxyisopropyl fumarate And a polyfunctional polymerization initiator having both a polymerizable unsaturated group.

Of these, more preferred are 1,
1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxycyclohexane, di-tert-butylperoxyhexahydroterephthalate, di-tert-butylperoxy Azelate and 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, and t-butylperoxyallyl carbonate.

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

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

These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator. However, in order to keep the efficiency of the polyfunctional polymerization initiator appropriate, It is preferable to add it after the half-life indicated by the polyfunctional polymerization initiator in the process.

These initiators are preferably used in an amount of 0.05 to 2 parts by mass based on 100 parts by mass of the monomer from the viewpoint of efficiency.

It is also preferable that the binder resin is crosslinked with a crosslinking monomer.

As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. Specific examples include aromatic divinyl compounds (eg, divinylbenzene, divinylnaphthalene, etc.); diacrylate compounds linked by an alkyl chain (eg, 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 methacrylate); diacrylate compounds linked by an alkyl chain containing an ether bond (for example, diethylene glycol diacrylate, triethylene glycol) Diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate); Diacrylate compounds linked by a chain containing, for example, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propanediacryle DOO, 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 the multifunctional crosslinking agent, pentaerythritol acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and acrylates of the above compounds are replaced with methacrylate. And triallyl cyanurate and triallyl trimellitate.

These cross-linking agents can be used in combination with other monomer components 10
It is preferable to use 0.00001 to 1 part by mass, preferably 0.001 to 0.05 part by mass with respect to 0 parts by mass.

Among these crosslinkable monomers, those which are preferably used from the viewpoints of toner fixability and offset resistance, include an aromatic divinyl compound (particularly divinylbenzene), a chain containing an aromatic group and an ether bond. Diacrylate compounds.

As other synthesis methods, a bulk polymerization method and a solution polymerization method can be used. However, in the bulk polymerization method, a polymer having a low molecular weight can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control. In that regard, the solution polymerization method utilizes a difference in radical chain transfer depending on the solvent,
Further, it is preferable to adjust the amount of the initiator and the reaction temperature because a polymer having a desired molecular weight can be easily obtained under mild conditions. In particular, in terms of minimizing the amount of initiator used and minimizing the effects of residual initiator,
A solution polymerization method under a pressurized condition is also preferable.

The composition of the polyester resin used in the present invention is as follows.

Examples of the dihydric alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol and 1,5-pentanediol. , 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-
Hexanediol, hydrogenated bisphenol A, and bisphenol represented by formula (A) and derivatives thereof;

[0130]

Embedded image (Wherein R is an ethylene or propylene group, x,
y is an integer of 0 or more, and the average value of x + y is 0 to 10. )

Diols represented by the formula (B):

[0132]

Embedded image

Examples of the divalent acid component include phthalic acid and
Benzenedicarboxylic acids such as terephthalic acid, isophthalic acid and phthalic anhydride or their anhydrides and lower alkyl esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or their anhydrides and lower alkyl esters; n- Alkenyl succinic acids or alkyl succinic acids such as dodecenyl succinic acid, n-dodecyl succinic acid, or anhydrides and lower alkyl esters thereof; fumaric acid, maleic acid, citraconic acid, unsaturated dicarboxylic acids such as itaconic acid or anhydrides, lower acids And dicarboxylic acids such as alkyl esters; and derivatives thereof.

It is preferable to use a trivalent or higher valent alcohol component or a trivalent or higher valent acid component which functions as a crosslinking component, alone or in combination.

As the polyhydric alcohol component having 3 or more valences,
For example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,
3,5-trihydroxybenzene and the like.

In the present invention, the trivalent or higher polyvalent carboxylic acid component includes, for example, trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid,
2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,2
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-
Octanetetracarboxylic acid, empol trimer acid, and anhydrides and lower alkyl esters thereof;

[0137]

Embedded image (Wherein X is an alkylene group or alkenylene group having 5 to 30 carbon atoms having at least one side chain having 3 or more carbon atoms), such as tetracarboxylic acids, and anhydrides and lower alkyl esters thereof. And polyvalent carboxylic acids and derivatives thereof.

The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol%.
%, 60 to 40 mol% as an acid component, preferably 5%
It is preferably from 5 to 45 mol%. The content of the trivalent or higher polyvalent component is preferably 5 to 60 mol% of all components.

The polyester resin is obtained by a generally known condensation polymerization.

The toner of the present invention may contain a wax.

The wax used in the present invention includes the following. For example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxides of aliphatic hydrocarbon waxes such as polyethylene oxide wax Or a block copolymer thereof; a plant wax such as candelilla wax, carnauba wax, wood wax, jojoba wax; an animal wax such as beeswax, lanolin, and whale wax; a mineral wax such as ozokerite, ceresin, petrolactam; Waxes; waxes mainly containing aliphatic esters such as montanic acid ester wax and caster wax; and those obtained by partially or entirely deoxidizing aliphatic esters such as deoxidized carnauba wax. . Further, saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a longer-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and barinaric acid; stearyl alcohol Saturated alcohols such as eicosyl alcohol, behenyl alcohol, kaunavir alcohol, seryl alcohol, melisyl alcohol, or alkyl alcohols having a longer chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amide, oleic acid amide;
Aliphatic amides such as lauric amide; saturated aliphatic bisamides such as methylenebisstearic acid amide, ethylenebiscapramide, ethylenebislauric amide, hexamethylenebisstearic acid amide; ethylenebisoleic amide, hexamethylenebisolein Acid amide, N, N′-dioleyladipamide, N, N
Unsaturated fatty acid amides such as N'-dioleyl sebacamide; m-xylene bisstearic acid amide;
Aromatic bisamides such as N'-distearyl isophthalic acid amide; aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metallic soaps); aliphatic hydrocarbons Wax grafted with a vinyl monomer such as styrene or acrylic acid on wax; partially esterified product of fatty acid such as behenic acid monoglyceride and polyhydric alcohol; having hydroxyl group obtained by hydrogenating vegetable oil or fat Methyl ester compounds are mentioned.

Further, these waxes may be obtained by sharpening the molecular weight distribution using a press sweating method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a liquid crystal deposition method, or a low molecular weight solid fatty acid. Also, those from which low-molecular-weight solid alcohols, low-molecular-weight solid compounds and other impurities have been removed are preferably used.

A fluidity improver may be added to the toner of the present invention. The fluidity improver can be added to the toner particles to increase the fluidity before and after the addition. For example, fluororesin powders such as vinylidene fluoride fine powder, polytetrafluoroethylene fine powder; fine powder silica such as wet-process silica and dry-process silica, fine powder titanium oxide, fine powder alumina, and silane compounds thereof. There are titanium coupling agent, silica treated by surface treatment with silicone oil, etc., and inorganic fine powders include oxides such as zinc oxide and tin oxide; strontium titanate, barium titanate, calcium titanate, strontium zirconate And complex oxides such as calcium zirconate; carbonate compounds such as calcium carbonate and magnesium carbonate.

Preferred fluidity improvers are fine powders produced by vapor phase oxidation of silicon halides, and are so-called dry silica or fumed silica. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows. SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

In this production step, it is possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride or titanium chloride together with the silicon halide. They are also included. The particle size is preferably in the range of 0.001 to 2 μm as an average primary particle size, and particularly preferably silica fine powder having a range of 0.002 to 0.2 μm is used.

Examples of commercially available fine silica powder produced by the vapor phase oxidation of silicon halides include those commercially available under the following trade names, for example.

AEROSIL (Nippon Aerosil) 130 200 300 380 TT600 MOX170 MOX80 COK84 Ca-O-SiL (CABOT Co.) M-5 MS-7 MS-75 HS-5 EH-5 Wacker HDKN 20 (WACKER-) CHEMIE GMBH) V15 N20E T30 T40 DC Fine Silica (Dow Corning Co.) Fransol (Fransil)

Further, a treated silica fine powder obtained by subjecting a silica fine powder produced by vapor phase oxidation of the silicon halide compound to a hydrophobic treatment is more preferable. It is particularly preferable that the treated silica fine powder is obtained by treating the silica fine powder such that the degree of hydrophobicity measured by a methanol titration test shows a value in the range of 30 to 80.

[0149] The hydrophobizing method is applied by chemically treating with an organic silicon compound or the like which reacts or physically adsorbs with the silica fine powder. The preferred method is
The silica fine powder produced by the vapor phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of the organosilicon compound include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethtridimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule, and Si located at the terminal unit and one each for Si And a dimethylpolysiloxane having a hydroxyl group bonded thereto. Further, a silicone oil such as dimethyl silicone oil may be used. These are used alone or as a mixture of two or more.

The fluidity improver has a specific surface area by nitrogen adsorption measured by the BET method of 30 m ² / g or more, preferably 5 m ² / g or more.
Those of 0 m ² / g or more give good results. Toner 1
0.01 to 8 parts by mass of the fluidity improver with respect to 00 parts by mass,
Preferably, 0.1 to 4 parts by mass is used.

To prepare a toner, a mixture containing at least a binder resin, magnetic iron oxide and an organometallic compound is used as a material. If necessary, wax and other additives are used. These materials were thoroughly mixed by a mixer such as a Henschel mixer or a ball mill, and then melted, kneaded and kneaded using a hot kneader such as a roll, kneader and extruder to make the resins compatible with each other. Then, a pigment or dye is dispersed or dissolved, and after cooling and solidifying, pulverization and classification are performed to obtain a toner. In the method for producing the toner of the present invention, the following production apparatus can be used depending on the situation.

Examples of the toner manufacturing apparatus include, for example, a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); a super mixer (manufactured by Kawata); a ribocorn (manufactured by Okawara Seisakusho); Spiral Pin Mixer (manufactured by Taiheiyo Kiko Co., Ltd.); Reedige Mixer (manufactured by Matsubo Co., Ltd.). Kneading machines include KRC Kneader (manufactured by Kurimoto Iron Works Co., Ltd.); Bus
s); TEM extruder (Toshiba Machine); TE
X twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); Kneedex (manufactured by Mitsui Mining); MS type Pressurized kneaders, kneader ruders (manufactured by Moriyama Seisakusho); Banbury mixers (manufactured by Kobe Steel Ltd.); examples of pulverizers include a counter jet mill, a micron jet, an inomizer (manufactured by Hosokawa Micron); an IDS mill, and a PJM. Jet pulverizer (manufactured by Nippon Pneumatic Industries, Ltd.); cross-jet mill (manufactured by Kurimoto Iron Works); ulmax (manufactured by Nisso Engineering); SK Jet O Mill (manufactured by Seishin Enterprise); Kryptron (Kawasaki) Heavy Industry Co., Ltd.); Turbo Mill (Turbo Kogyo Co., Ltd.); Fire, (manufactured by Seishin Enterprise Co.) space Dick crush fire; Turbo crush Fire (Nisshin Engineering Inc.); micron separator, Turboplex (ATP), TSP
Separators (manufactured by Hosokawa Micron); elbow jets (manufactured by Nippon Mining Co., Ltd.); dispersion separators (manufactured by Nippon Pneumatic Industries); YM microcuts (manufactured by Yasukawa Shoji Co., Ltd.). As the sieving device used, Ultrasonic (Koei Sangyo Co., Ltd.); Resona Sieve, Gyro Shifter (Tokuju Kogyo Co., Ltd.); Vibrasonic System (Dalton Co., Ltd.); Sonic Clean (Shinto Kogyo Co., Ltd.); Turbo Screener (Manufactured by Turbo Kogyo Co., Ltd.); micro-shifters (manufactured by Makino Sangyo Co., Ltd.);

[0154]

The present invention will be described in more detail with reference to the following examples, which do not limit the present invention in any way.

<Production example 1 of azo iron compound> 4-Chloro-
A monoazo compound synthesized by a general diazo coupling reaction of 2-aminophenol and 6-t-octyl-2-naphthol was converted to N, N-dimethylformamide (D
MF) and stirred. Sodium carbonate was added to this solution, the temperature was raised to 70 ° C., iron (II) sulfate heptahydrate was added, and the mixture was reacted for 5 hours. After cooling to room temperature, the precipitated product was collected by filtration, added to isopropanol, dissolved by heating at 70 ° C., and gradually cooled to room temperature over 24 hours to obtain a highly crystalline azo iron compound. Was precipitated. This liquid was directly filtered from isopropanol, and the filtrate was washed with water and dried to obtain an azo iron compound (I) represented by the following formula. Crystallinity of azo iron compound (I) is 96%
Met.

The X-ray diffraction spectrum of the azo iron compound (I) is shown in FIG.

[0157]

Embedded image

<Production example 2 of azo iron compound> A production method of azo iron compound was prepared in the same manner as in Production Example 1 of azo iron compound except that 4-t-pentyl-2-aminophenol was used as a raw material. An azo iron compound (II) represented by the following formula (II) was obtained. The crystallinity of the azo iron compound (II) was 97%.

[0159]

Embedded image

<Production Example 3 of Azo Iron Compound> The same method as in Production Example 1 of azo iron compound was used except that 2-aminophenol was used as a raw material in Production Example 1 of azo iron compound, and the following formula (III) was used. The azo iron compound (III) represented was obtained. The crystallinity of the azo iron compound (III) was 94%.

[0161]

Embedded image

<Production example 4 of azo iron compound> The same procedure as in Production example 1 of azo iron compound was carried out, except that 6-t-butyl-2-naphthol was used as a raw material in Production example 1 of azo iron compound. The azo iron compound represented by the formula (IV) (I
V) was obtained. Crystallinity of azo iron compound (IV) is 90%
Met.

[0163]

Embedded image

<Preparation Example 5 of Azo Iron Compound> The following formula (I) was prepared using the same method as in Preparation Example 1 of Azo Iron Compound, except that 6-methyl-2-naphthol was used as a raw material. An azo iron compound (V) represented by V) was obtained. The crystallinity of the azo iron compound (V) was 91%.

[0165]

Embedded image

<Azoiron compound production example 6> The following formula was used in the same manner as in the azoiron compound production example 1 except that 3-n-butyl 2-naphthol was used as a raw material in the azoiron compound production example 1. The azo iron compound represented by (VI) (V
I) was obtained. Crystallinity of azo iron compound (VI) is 84%
Met.

[0167]

Embedded image

<Production Example 7 of Azo Iron Compound> A method similar to that of Production Example 1 of Azo iron compound, except that 2-naphthol and 4-methyl-2-aminophenol were used as raw materials in Production Example 1 of azo iron compound. Was used to obtain an azo iron compound (VII) represented by the following formula (VII). The crystallinity of the azo iron compound (VII) was 91%.

[0169]

Embedded image

<Production Example 8 of Azo Iron Compound> In Production Example 7 of an azo iron compound, N, N-dimethylformamide (DMF) was used without performing the crystallization process in isopropanol.
The reaction solution was dispersed in water, filtered, washed with water, and dried to obtain an amorphous azo iron compound (VIII). The crystallinity of the azo iron compound (VIII) was 15%.

<Preparation Example 9 of Azo Iron Compound> A compound of the following formula (IX) was prepared in the same manner as in Preparation Example 1 of azo iron compound except that 2-naphthol was used as a raw material in Preparation Example 1 of azo iron compound. Azo iron compound (IX) to be obtained was obtained. The crystallinity of the azo iron compound (IX) was 95%.

[0172]

Embedded image

<Azochrome Compound Production Example 10> In the azo iron compound production example 1, 2-naphthol, 4-t-pentyl-2-aminophenol, chromium formate (II
An azochrome compound (X) represented by the following formula (X) was obtained in the same manner as in Production Example 1 of azo iron compound except that I) was used. The azochrome compound (X) has a crystallinity of 8
8%.

[0174]

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(Production Example of Magnetic Iron Oxide) (Production Example 1) Sodium silicate was added to an aqueous ferrous sulfate solution so that the content of silicon element with respect to iron element was 0.48%. Caustic soda solution was mixed to prepare an aqueous solution containing ferrous hydroxide. Air was blown in while adjusting the pH of the aqueous solution to carry out an oxidation reaction at 80 to 90 ° C. to prepare a slurry liquid for generating seed crystals.

When the formation of seed crystals was confirmed, an aqueous ferrous sulfate solution was further added to this slurry liquid as appropriate, and p
While adjusting H, air was blown in to advance the oxidation reaction. In the meantime, the distribution of metal elements in the magnetic iron oxide is controlled by adding zinc sulfate as appropriate while checking the progress rate of the reaction while checking the concentration of unreacted ferrous hydroxide, and further adjusting the pH of the aqueous solution. Then, the oxidation reaction was completed. The produced magnetic iron oxide particles were washed, filtered, dried and pulverized by a conventional method to obtain magnetic iron oxide 1.

Table 1 shows the relationship between the contents of the iron element, the Zn element and the silicon element and the properties of the obtained magnetic iron oxide 1.
2 and 3 show the content ratio of each metal element in the magnetic iron oxide with respect to the iron element dissolution rate. The content of each metal element existing up to the iron element dissolution rate of 20% by mass was determined from the graph shown in FIG.

(Production Examples 2 to 8) Amount of sodium silicate added,
Magnetic iron oxides 2 to 8 having the physical properties shown in Table 1 were obtained in the same manner as in Production Example 1 except that the amount of zinc sulfate was changed.

[0179]

[Table 1]

Example 1 100 parts by mass of styrene-n-butyl acrylate copolymer (copolymerization ratio = 70: 30, Mw = 300,000, Tg = 60 ° C.) Magnetic iron oxide 1 100 of Production Example 1 Parts by mass-Iron azo compound (I) 2 parts by mass-Low molecular weight polypropylene 3 parts by mass The above mixture is melt-kneaded with a biaxial extruder heated to 140 ° C, and the cooled kneaded material is roughly pulverized with a hammer mill. The coarsely pulverized product was finely pulverized by a jet mill, and the obtained finely pulverized powder was classified by a fixed wall type air classifier to produce a classified powder. In addition, the obtained classified powder is multi-divided using the Coanda effect (Nippon Mining Co., Ltd. elbow jet classifier)
Then, ultrafine powder and coarse powder were strictly classified and removed at the same time to obtain negatively chargeable magnetic toner particles having a weight average particle diameter (D4) of 6.7 μm.

Hydrophobic silica fine powder (BET 200 m ^{2 /} g) treated with 100 parts by mass of the magnetic toner particles, dimethyldichlorosilane treatment, hexamethyldisilazane treatment, and then dimethylsilicone oil treatment
Parts by mass were mixed with a Henschel mixer to prepare a negatively-chargeable magnetic toner 1.

(Image Output Test) Using a Canon laser beam printer LBP-1760 from 16 sheets / min to 24 sheets / min.
Using a modified image forming apparatus, 500 g of the magnetic toner 1 was filled in a process cartridge. The process cartridge filled with the externally added magnetic toner was mounted on the image forming apparatus main body. The process speed at this time is
About 140 mm / sec. Met.

Under a high temperature and high humidity environment (32.5 ° C., 85% R
H) and under a low-temperature and low-humidity environment (15 ° C., 10% RH), a printout test was performed on 20,000 sheets while toner was supplied, and the obtained images were evaluated for the following items.

(1) Image Density Evaluation was made based on the image density of an image printed on ordinary plain paper for copying machines (basis weight: 75 g / m ² ). The image density was measured using a Macbeth reflection densitometer (manufactured by Macbeth).
The relative density with respect to the printout image of the white background portion where the document density was 0.00 was measured.

(2) The whiteness (Dr) of the transfer paper before printing measured with a fog reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness (DS) of the transfer paper after printing solid white. Difference (DS-D
Fog was calculated from r). The environment in which the image was formed was low temperature and low humidity (15 ° C., 10% RH).

(3) Toner Consumption A normal temperature and normal humidity environment (23 ° C., 60
% RH), a latent image line width is set to about 420 μm in a 10-dot horizontal line pattern of 600 dpi, and an image of 4% printing rate is printed on A4 size paper.
00 sheets were output, and the consumption was determined from the change in the amount of toner in the developing device. Further, a solid black image was output, and the image density at this time was confirmed.

Further, a latent image of a 10-dot horizontal line pattern of 600 dpi (latent image line width: about 420 μm) was written at 1 cm intervals, developed, transferred and fixed on a PET OHP. The obtained horizontal line pattern image was obtained by using a surface roughness meter surf coder SE-30H (manufactured by Kosaka Laboratories) as a method of applying toner on the horizontal line as a surface roughness profile, and the line width was determined from the width of this profile. Was. When the line width is slightly thicker than the latent image line width, an image with the highest sharpness is obtained, and as the line width becomes narrower than the latent image line width, the reproducibility of a thin line decreases.

A toner having a high image density, an appropriate line width, and a small amount of toner consumption is preferable. A toner having a low image density and a small amount of toner consumption, and a toner having a small line width and a small amount of toner consumption are preferable. Not a preferred form.

(4) Image quality Using the above-described image-drawing tester, an isolated 1-dot pattern was imaged, and an image was observed with an optical microscope to evaluate dot reproducibility. ：: The toner does not protrude from the latent image at all, and the dots are completely reproduced. Δ: The toner protrudes from the latent image slightly. ×: The toner protrudes from the latent image.

(5) Trailing Using the above-described image output tester, a 4-dot horizontal line was set to 20 lines.
The pattern printed in the dot space was drawn, and the number of trails on the line was counted. ：: no occurrence △: less than 3 △: 3 to less than 7 ×: 7 to less than 15 ×: 15 or more

Examples 2 to 14 and Comparative Examples 1 to 4 Negatively chargeable magnetic toners 2 to 2 were prepared in the same manner as in Example 1 except that the magnetic iron oxide and the azo iron compound were changed as shown in Table 2. 18
Was prepared and evaluated.

Table 2 shows the evaluation results.

[0193]

[Table 2]

[0194]

According to the present invention, it is possible to provide a toner which maintains high image quality and high image density even after long-term use, has excellent environmental stability, does not cause tailing, and consumes a small amount of toner. Can be.

[Brief description of the drawings]

FIG. 1 shows an X-ray diffraction spectrum of an azo iron compound (I) used in the present invention.

FIG. 2 shows the relationship between the iron element dissolution rate of the magnetic iron oxide 1 used in the present invention and the content of each metal element in the magnetic iron oxide.

FIG. 3 shows the relationship between the iron element dissolution rate of the magnetic iron oxide 1 used in the present invention and the content of each metal element in the magnetic iron oxide.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroshi Yusa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Katsuhisa Yamazaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Shuhei Moribe 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hirohide Tanigawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H005 AA02 AA06 CA22 CB03 CB07 DA01 EA07

Claims (18)

[Claims] 1. A toner containing at least a binder resin, a magnetic iron oxide and an organometallic compound, wherein the organometallic compound comprises one or more alkyl groups and two hydroxyl groups capable of binding to an iron atom. A magnetic iron oxide that can be produced from a monoazo compound having the following formula: wherein the magnetic iron oxide contains at least 0.1 to 4.0% by mass of Zn based on the magnetic iron oxide. 2. The toner according to claim 1, wherein the magnetic iron oxide contains at least 0.1 to 2.0% by mass of Zn based on the magnetic iron oxide. 3. The toner according to claim 1, wherein the magnetic iron oxide contains at least 0.2 to 2.0% by mass of Zn based on the magnetic iron oxide. 4. The toner according to claim 1, wherein the magnetic iron oxide contains at least 0.2 to 1.0% by mass of Zn based on the magnetic iron oxide. 5. In the magnetic iron oxide, a Zn content B _Zn existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by mass, and a total content A of Zn present in the magnetic iron oxide. _Zn
5. The toner according to claim 1, wherein the ratio (B _Zn / A _Zn ) × 100 is 40 to 100%. 6. The toner according to claim 1, wherein the magnetic iron oxide contains 0.1 to 2.0% by mass of Si based on the magnetic iron oxide. 7. The magnetic iron oxide according to claim 1, wherein the Si content S _Si present on the surface of the magnetic iron oxide is 0.1 to 0.5% based on the magnetic iron oxide.
The toner according to claim 6, wherein the content is from 0.01 to 0.5% by mass. 8. The content S _{Si of} Si present on the surface of the magnetic iron oxide and the total content T _{Si of} Si present in the magnetic iron oxide.
The toner according to claim 6, wherein the ratio (S _Si / T _Si ) × 100 is 10 to 55%. 9. The ratio (B _Si) of the content B _{Si of} Si present when the dissolution rate of the iron element of the magnetic iron oxide is up to 20% by mass and the total content T _{Si of} Si present in the magnetic iron oxide. / T _Si ) × 1
9. The toner according to claim 6, wherein 00 is 40 to 90%. 10. The toner according to claim 1, wherein the azo iron compound is crystalline. 11. The toner according to claim 1, wherein the monoazo compound is represented by the following general formula (a), (b) or (c). Embedded image (In the formula, R _{1 to} R ₈ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{1 to} R ₈ is an alkyl group.) (In the formula, R _{9 to} R ₁₈ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{9 to} R ₁₈ is an alkyl group.) (In the formula, R _{19 to} R ₃₀ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{19 to} R ₃₀ is an alkyl group.) 12. The monoazo compound represented by the following general formula (b)
The toner according to claim 1, wherein the toner is represented by the following formula. Embedded image (In the formula, R _{9 to} R ₁₈ each independently represent a hydrogen atom, a halogen atom or an alkyl group, and at least one of R _{13 to} R ₁₈ is an alkyl group.) 13. The toner according to claim 1, wherein the monoazo compound has an alkyl group having 4 to 12 carbon atoms as a substituent. 14. The toner according to claim 1, wherein the monoazo compound has an alkyl group having 6 to 10 carbon atoms as a substituent. 15. The toner according to claim 1, wherein the monoazo compound has a tertiary alkyl group having 4 to 12 carbon atoms as a substituent. 16. The toner according to claim 1, wherein the monoazo compound has a tertiary alkyl group having 6 to 10 carbon atoms as a substituent. 17. The toner according to claim 1, wherein the azo iron compound is represented by the following general formula (d), (e) or (f). Embedded image (In the formulas (d), (e) and (f), A and B each independently represent o-phenylene or 1,2-naphthylene;
At least one of A and B has one or more alkyl groups. A and B each may further have a halogen atom as a substituent. M is a cation and represents a hydrogen ion, an alkali metal ion, an ammonium ion, or an organic ammonium ion. ) 18. The method according to claim 18, wherein the monoazo compound is used as the binder resin 10.
18. The toner according to claim 1, wherein the toner is contained in an amount of 0.1 to 10 parts by mass with respect to 0 parts by mass.