JP2002323794A - Magnetic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic toner showing a stable sleeve coat state and giving preferable image density and image quality even when the toner is left to stand for a long time in a low humidity environment or high humidity environment or the temperature in a device is increased by continuous use. SOLUTION: The magnetic toner contains at least a binder resin, magnetic iron oxide and wax. As for the wetting property of the magnetic toner with respect to a mixture solvent of methanol and water measured as the transmittance for light at 780 nm wavelength, the methanol concentration is 65 to 80 vol.% when the transmittance is 80%, and the methanol concentration is 65 to 80 vol.% when the transmittance is 10%. The magnetic iron oxide contains at least one element α selected from Mg, Al, Si, Zn, Ti and Zr by 0.10 to 4.00 mass% in terms of magnetic iron oxide. When the solubility of the iron element in the magnetic iron oxide is 20%, the solubility R of the element α is >=44% and <=100%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic 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 Apparatuses using electrophotography are widely used not only in copiers for copying original documents, but also in fields such as printers and facsimile machines as computer outputs.

In recent years, such devices have been sought to be smaller, lighter, faster, and more reliable, and machines have become simpler in various respects. Is coming. As a result, the performance required of the toner becomes higher, and if the performance of the toner cannot be improved, a better machine cannot be realized.

[0004] Various proposals have been made regarding a technique for improving the developability and durability of the toner by controlling the hydrophobic property of the toner to a specific solvent. JP 11
JP-A-194533 discloses that the toner is dispersed in a mixed solution of ethyl alcohol and water, the absorbance at that time is measured, and the amount of magnetic iron oxide present on the surface of the magnetic toner is known. There is disclosed a technique that can easily determine how much contamination of a roller and fusion of a magnetic toner to a photosensitive drum occur.

[0005] However, a toner having a small amount of magnetic iron oxide on the surface is effective for the above-described stain and fusing,
The state of existence of magnetic iron oxide on the surface of the magnetic toner cannot be said to be appropriate, and poor charging of the magnetic toner due to too little magnetic iron oxide on the surface of the magnetic toner, and sleeve due to uneven charging distribution of the magnetic toner. There are problems such as the occurrence of the above blotch (toner coat defect).

Japanese Patent Application Laid-Open No. 2000-242027 discloses a method in which the hydrophobic property of a toner is represented by an ethanol drop transmittance curve, the transmittance with respect to the ethanol content is measured, and the toner having a constant wetting property with respect to ethanol. Is disclosed. Although the toner having such characteristics is effective in preventing the fusion of the drum and suppressing the image flow, the dispersion state of the raw material on the surface of the toner is not sufficiently controlled, and the toner caused by the surface state of the toner is not sufficiently controlled. There is still room for improvement in the control of the charge amount.

Further, various developing methods have been put into practical use in the electrophotographic developing method. Among them, magnetic toners have been used since they have less trouble with a developing device having a simple structure, have a long life and are easy to maintain. Is preferably used. In such a developing method, the quality of image formation largely depends on the performance of the magnetic toner. Further, in the magnetic toner, the toner is provided with magnetism by containing magnetic iron oxide. For these reasons, magnetic iron oxide affects the developability and durability of magnetic toner, and various proposals have been made for magnetic iron oxides, such as magnesium, aluminum, silicon, phosphorus, and sulfur. There are magnetic iron oxides containing zinc, zinc and the like, and have obtained various effects.

For example, JP-A-6-144840 discloses magnetite particles containing magnesium, which are disclosed in JP-A-5-72801 and JP-A-5-2136.
No. 20, JP-A-7-175262, JP-A-7-175262
JP-A-239571, JP-A-7-110598 and JP-A-11-153882 disclose magnetite particles containing aluminum and silicon.
JP-A-8-50369, JP-A-8-101529
JP, JP-A-7-175262, JP-A-8-4
JP-A-8524, JP-A-8-208236 and JP-A-8-208237 disclose magnetite particles containing zinc, and are disclosed in JP-A-11-157843, JP-A-11-189420, and JP-A-11-189420. −31
Japanese Patent No. 6474 discloses magnetite particles containing silicon and other elements.

Although the above-mentioned ones show good developability, further improvement in developability and durability is expected when applied to a high-speed development system or when applied to a simple development system. In rare cases, there is still room for improvement with respect to problems such as sleeve blotting and image scattering, which are caused by toner fluidity and chargeability, and that the developing property is lowered by increasing the temperature inside the apparatus.

[0010]

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

An object of the present invention is to provide a magnetic toner capable of obtaining good image quality even in a high-speed developing system.

An object of the present invention is to provide a magnetic toner which does not cause sleeve blotting.

An object of the present invention is to provide a magnetic toner capable of obtaining good developability and durability even under a low humidity environment and a high humidity environment.

An object of the present invention is to provide a magnetic toner capable of obtaining good image density and image quality even after the apparatus has been left for a long period of time or in a state where the temperature inside the apparatus has been increased due to continuous use.

[0015]

Specifically, the present invention provides:
A magnetic toner containing at least a binder resin, a magnetic iron oxide, and a wax. The magnetic toner has a transmittance of 80% as measured by the transmittance of light having a wavelength of 780 nm in wettability with a mixed solvent of methanol and water. And the methanol concentration when the transmittance is 10% is 65 to 80% by volume.
Wherein the magnetic iron oxide is Mg, Al, Si, Z
a magnetic iron oxide containing at least one element α selected from n, Ti, and Zr in an amount of 0.10 to 4.00% by mass based on the magnetic iron oxide; Sometimes, the dissolution rate R of the element α is 44% or more and 100%.
% Or less.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies to solve the conventional problems, and as a result, have found that the wettability of a magnetic toner with respect to a specific solvent is controlled, and the magnetic iron oxide contained in the magnetic toner is controlled. By controlling the element distribution of
It has been found that the magnetic toner has excellent developability, durability, and fluidity, and that excellent image quality and durability stability can be obtained even at high speed development, elevated temperature inside the machine, or even when left unattended.

In the magnetic toner of the present invention, when the wettability to a methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, the methanol concentration in the methanol / water mixed solvent at the transmittance is within a specific concentration range. Belong to.

In the present invention, when the wettability of the magnetic toner with respect to a methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, the methanol concentration is in the range of 65 to 80% by volume when the transmittance is 80%. Further, when the transmittance is 10% and the methanol concentration is in the range of 65 to 80% by volume, the charging characteristics of the magnetic toner are stabilized, and under various environments such as low humidity, high humidity, and high temperature. Also exhibit excellent developability.

FIG. 1 is a graph showing the transmittance of light having a wavelength of 780 nm with respect to the methanol concentration of the magnetic toner of Example 1 of the present invention. The region where the transmittance exceeds 80% indicates that many magnetic toners are hardly wet with methanol, and the region where the transmittance is lower than 10% indicates that most magnetic toners are almost wet. . As shown in the graph, the transmittance of the magnetic toner of the present invention reaches 80% at a methanol concentration of 65 to 80% by volume, and reaches 10% at a methanol concentration of 65 to 80% by volume.
This means that most of the magnetic toner particles in the magnetic toner are wetted with methanol at the proper methanol concentration in the present invention, in other words, the surface composition is uniform within a certain range, and the charge uniformity is low. A magnetic toner having excellent charge stability.

The wettability of the magnetic toner with respect to the methanol / water mixed solvent is greatly affected by the surface material composition of the magnetic toner particles and the state of their existence. The less the magnetic iron oxide is exposed on the surface of the magnetic toner particles, that is, the greater the ratio of the surface of the magnetic toner particles covered with the binder resin component, the more the magnetic toner particles become wet with a higher methanol concentration. As the ratio of the binder resin component on the surface of the magnetic toner particles increases, the chargeability of the magnetic toner improves, and higher developability can be obtained. However, if the exposure of the magnetic iron oxide is too small, the magnetic toner cannot obtain proper charging performance, which is not preferable. In the present invention, the wettability of the magnetic toner with respect to a methanol / water mixed solvent is measured at a wavelength of 7.
When measured at a transmittance of 80 nm light, the transmittance is 80%.
When the methanol concentration at this time is in the range of 65 to 80% by volume, preferably 65 to 77% by volume, and more preferably 65 to 75% by volume, the binder resin exposed on the surface of the magnetic toner particles and the magnetic oxide The ratio of iron falls within an appropriate range, and the magnetic toner can maintain an appropriate charge amount.
The "appropriate range of exposure" means that the binder resin component is sufficiently and appropriately present on the surface of the magnetic toner particles to enhance the charging ability of the magnetic toner, and that the magnetic iron oxide is also appropriately exposed, so that the magnetic toner is appropriately exposed. Indicates that excessive charging is prevented.

When the transmittance is 80%, the methanol concentration is 6
If the content is lower than 5% by volume, a large number of magnetic toner particles having a large amount of magnetic iron oxide exposed on the surface are present, and the magnetic toner cannot be sufficiently charged, resulting in poor developability. The methanol concentration is 80 when the transmittance is 80%.
If it exceeds the volume percentage, it means that there are many magnetic toner particles with little exposure to the surface of the magnetic iron oxide, and the magnetic toner is excessively charged and cannot maintain an appropriate charge amount. Becomes unstable, sleeve blotting occurs, image density decreases, and fog increases.

When the wettability of the magnetic toner with respect to a methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, when the transmittance is 10%, the methanol concentration is 65%.
When it is within the range of from 80 to 80% by volume, preferably from 65 to 77% by volume, more preferably from 65 to 75% by volume, the exposure ratio of the binder resin and the magnetic iron oxide on the surface of most of the magnetic toner particles is appropriate. Within this range, the magnetic toner can maintain an appropriate charge amount. "Range where exposure is appropriate"
That is, it means that the binder resin component is sufficiently and appropriately present on the surface of the magnetic toner particles to enhance the charging ability of the magnetic toner, and that the magnetic toner is excessively charged by appropriately exposing the magnetic iron oxide. Means to prevent.

When the transmittance is 10%, the methanol concentration is 6
If the content is lower than 5% by volume, the proportion of the magnetic iron oxide exposed on the surface is high in most of the magnetic toner particles in the magnetic toner, and the magnetic toner cannot be sufficiently charged, and the developing property is increased at elevated temperature. Become inferior to When the methanol concentration exceeds 10% by volume when the transmittance is 10%, the ratio of the magnetic toner particles having the magnetic iron oxide properly exposed on the surface is small, and the magnetic toner is excessively charged and the magnetic toner is appropriately charged. Since the charge amount cannot be maintained, the image density decreases and fog increases.

The magnetic iron oxide of the present invention comprises Mg, Al, Si,
At least one element α selected from Zn, Ti, and Zr
Is 0.10 to 4.00 mass% based on the magnetic iron oxide. When the iron element solubility in the magnetic iron oxide is 20%, the solubility R of the element α is 44% or more and 10% or more.
0% or less. The magnetic iron oxide of the present invention thus contains the element α, the solubility R of the element α when the iron element dissolution rate is 20% is 44 to 100%, and the element α is unevenly distributed outside the magnetic iron oxide. Is a magnetic iron oxide. The content of the element α is preferably 0.20 to 3.50% by mass.
And more preferably 0.30 to 3.00 mass%.
The dissolution rate R is preferably 45 to 95%, and more preferably 45 to 90%.

Magnetic iron oxide Mg, Al, Si, Zn, T
By containing elements such as i and Zr in the magnetic iron oxide and having the elements outside the magnetic iron oxide, it is possible to increase the surface resistance of the magnetic iron oxide and also perform charge leakage due to moisture adsorption.
Therefore, although high charging is obtained for the magnetic toner,
It does not result in overcharging, and a constant charging level can be maintained. Therefore, in any environment,
If triboelectric charging is performed even after standing, the magnetic toner can have a high charge amount, and will have excellent developability. Further, by having a large amount of the element α on the outside like the magnetic iron oxide of the present invention, fluidity can be imparted to the magnetic toner,
It becomes a toner having excellent durability.

If the content of the element α is less than 0.10 mass, the effect of increasing the resistance and the effect of charge leakage cannot be obtained.
If it exceeds 4.00% by mass, the effect of charge leakage will increase, and the charge amount will decrease, especially the rise of charge after standing will be delayed, or the charge amount under high humidity will not be satisfied. If the dissolution rate R is less than 44%, the effects of the present invention will be reduced.

In order to improve the balance between the charge retention and the leakage, it is preferable to have two types of elements. The element α1 includes an element α1 selected from the element α, and further includes an element α2 different from the element α1. It is preferable that the content is 0.10 to 4.00% by mass, respectively.
It is preferable that the dissolution rate R1 of the element α1 when the iron element dissolution rate is 20% is 44 to 100% and the dissolution rate R2 of the element α2 when the iron element dissolution rate is 20% is 44 to 100%. More preferably, the element α2 is Mg, Al, Zn, and also in this case, the content is 0.10 to 4.00% by mass, respectively.
It is preferable that the dissolution rate R1 of the element α1 when the iron element dissolution rate is 20% is 44 to 100% and the dissolution rate R2 of the element α2 when the iron element dissolution rate is 20% is 44 to 100%. It is also preferable to contain an element β different from the element α, wherein the elements β are S and P, and the contents are 0.10 to 4.
It is preferably 00% by mass. Further, the dissolution rate R1 of the element α when the iron element dissolution rate is 20% is 44 to 100% and the dissolution rate R3 of the element β when the iron element dissolution rate is 20% is 0 to 4%.
It is preferably 0%.

As the element α1, Mg, Al, Zn, S
i is preferred, and Si is particularly preferred. As the element α2, Mg, Al, and Zn are preferable. As a result, the function is separated, and the balance between the charge and the leak can be kept moderately. It is also preferable that the element β is P or S. In this case, the function is strengthened, the effect of retaining and leaking charge is increased, and quick charge adjustment can be performed.

Particularly preferably, when Si is used as the element α1, the charge amount can be increased and the leak function can be more effectively performed. In this case, the content of Si is preferably 0.20 to 0.35% by mass, and more preferably 0.30% by mass.
The content is preferably up to 3.00% by mass. Dissolution rate R1 of Si
Is preferably 45 to 95%, more preferably 45 to 90%.

And, as the element α2, Mg, Al, Z
By having n, it is possible to increase the retention of electric charge, to reduce the reduction during leaving, and to make the rise of charging faster. In this case, the content of the element α2 is preferably 0.10 to 3.00% by mass, more preferably 0.15 to 3.05% by mass.
-2.50 mass% is good. The dissolution rate R2 of the element α2 is 50
-100% is preferable, and 60-100% is more preferable.

Alternatively, by having P and S as the element β, the presence of the element α on the surface can be increased to increase the charge retention, reduce the drop during standing, and increase the charge rise. Can be faster. In this case, the content of the element β is preferably 0.10 to 3.00% by mass,
Further, the content is preferably 0.15 to 2.50% by mass. The dissolution rate R3 of the element β is preferably 0 to 40%, and more preferably 5 to 30%.

Further, the synergistic effect of the element α1 and the element α2 balances the charge retention and the leakage at a high charge level, and reduces the charge change ripple to reduce the charge change ripple.
It is preferable that 2> R1.

In continuous development in a high-speed developing system, it is particularly required that the magnetic toner regulated by the regulating blade is charged quickly and uniformly on a developer carrier, a so-called developing sleeve. As a result, a good image can always be provided even in a high-speed developing system.However, if the magnetic toner is non-uniformly charged and the distribution of the amount of charge is uneven, the subsequent image is developed when continuously developed. When developing the toner, the variation in the amount of charge of the magnetic toner supplied on the developing sleeve and the amount of charge of the magnetic toner on the sleeve becomes large, and an image with much scattering may be generated. In addition, a portion having a high charge amount is locally formed, the toner coat becomes non-uniform, and sleeve blotting may occur.

The charge amount distribution of the magnetic toner is greatly affected by the material dispersibility on the surface of the magnetic toner, and the more uniform the material dispersibility, the more uniform the charge amount distribution. The material dispersibility of the surface of the magnetic toner can be known by measuring the wettability behavior of the magnetic toner with a mixed solvent of methanol and water. The more uniform the material dispersibility on the surface, the smaller the difference in methanol concentration from when the magnetic toner starts to wet the mixed solvent of methanol / water until when the magnetic toner is completely wetted. In the present invention, when the wettability of the magnetic toner with respect to the methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, the methanol concentration is 65 to 8 when the transmittance is 80%.
0% by volume, and when the methanol concentration at a transmittance of 10% is within a range of 65 to 80% by volume, the methanol concentration and the transmittance at a transmittance of 80% are 10%. %, The difference in methanol concentration becomes smaller,
That is, the charge amount distribution of the magnetic toner is made uniform, and uniform and high chargeability can be quickly imparted to the magnetic toner. The magnetic iron oxide of the present invention can further promote this effect. Also, at this time, the magnetic toner having a high chargeability has poor fluidity, and the magnetic toner tends to locally aggregate fine powder on the developing sleeve, which may result in sleeve blotting. In the present invention, since the magnetic iron oxide has the element α on the outside and is abundantly present on the surface of the magnetic iron oxide, the magnetic iron oxide promotes uniform charging on the surface of the magnetic toner. Can be prevented.

In the present invention, when the magnetic iron oxide is exposed on the surface of the magnetic toner, the magnetic iron oxide is exposed to a part of the surface area of the magnetic toner because it has an appropriate methanol wettability in the present invention. That is, the ratio of the magnetic iron oxide exposed on the surface of the magnetic toner in a large area is small. However, the presence of the element α on the outside of the magnetic iron oxide makes it possible to exert the effect more effectively with a small amount. In addition, the presence of the element α can impart good fluidity to the magnetic toner without deteriorating the high and uniform chargeability of the magnetic toner. , The developability can be maintained and image deterioration can be effectively prevented.

When the methanol concentration is 6 when the transmittance is 80%,
If the methanol concentration is lower than 5% by volume or the methanol concentration at a transmittance of 10% is lower than 65% by volume, the charge amount distribution of the magnetic toner becomes broad, the developability is poor, and the scattering is deteriorated. When the methanol concentration at a transmittance of 80% exceeds 80% by volume, or when the methanol concentration at a transmittance of 10% exceeds 80% by volume, the magnetic iron oxide becomes excessively charged or the magnetic toner has The charge amount distribution becomes broad, and non-uniformly charged magnetic toner particles are present, so that sleeve blotting deteriorates.

The magnetic iron oxide is composed of Mg, Al, Si, Z
a magnetic iron oxide containing at least one element α selected from n, Ti, and Zr in an amount of 0.10 to 4.00% by mass based on the magnetic iron oxide; Sometimes, the dissolution rate R of the element α is 44% or more and 100%.
%, The magnetic toner tends to agglomerate, the fluidity becomes insufficient, and the deterioration of the developing property due to sleeve blotting and temperature rise is promoted.

In the present invention, the wettability of the magnetic toner,
That is, the hydrophobic property is measured using a methanol drop transmittance curve. Specifically, as the measuring device, for example,
Powder wettability tester WET-100P manufactured by Resca Corporation
And a methanol drop transmittance curve measured under the following conditions and procedures using the following method. First, methanol 60% by volume
And 70 ml of a water-containing methanol solution comprising 40% by volume of water
Is placed in a container, and the magnetic toner as a sample is shaken with a mesh having a mesh size of 150 μm, and 0.1 g of the magnetic toner passing through the mesh is precisely weighed and added to measure the hydrophobic property of the magnetic toner. Prepare a sample solution. next,
1.3 ml / methanol was added to this sample solution for measurement.
min. 780 while continuously adding at a dropping speed of
The transmittance is measured with light of nm, and a methanol drop transmittance curve as shown in FIG. 1 is prepared. In this case, the reason why methanol was used as the titration solvent is that the influence of the elution of the dye, pigment, charge control agent and the like contained in the magnetic toner particles is small, and the surface state of the magnetic toner can be observed more accurately.

As one of the production methods for achieving the above-mentioned wettability, in the present invention, a mechanical pulverizer as shown in FIGS. 3, 4 and 5 is used. Since the treatment and the surface treatment can be performed, the efficiency is improved, which is preferable. In this pulverizer, the surface state of the magnetic iron oxide on the surface of the magnetic toner can be controlled by adjusting the temperature during the pulverization and using the magnetic iron oxide having the composition of the present invention.

Hereinafter, the mechanical crusher shown in FIGS. 3, 4 and 5 will be described. FIG. 3 shows a schematic cross-sectional view of an example of a mechanical crusher used in the present invention,
FIG. 4 is a schematic sectional view taken along the line DD ′ in FIG. 3, and FIG. 5 is a perspective view of the rotor 314 shown in FIG. The device comprises a casing 313, a jacket 316, a distributor 2 as shown in FIG.
20, a rotor 314 in a casing 313 having a number of grooves provided on a high-speed rotating surface composed of a rotating body attached to a center rotating shaft 312, and arranged at regular intervals on the outer periphery of the rotor 314; A stator 310 having a large number of grooves on its surface, a raw material input port 311 for introducing a raw material to be processed, and a raw material discharge port 302 for discharging processed powder. ing.

Normally, when the pulverized raw material is pulverized by a mechanical pulverizer, the temperature T1 of the spiral chamber 212 of the mechanical pulverizer and the rear chamber 3
A method of controlling the temperature of the temperature T2 of 20 and performing pulverization at a temperature equal to or lower than Tg of the resin and not performing surface modification is selected. However, in order to obtain a magnetic toner having the characteristics characteristic of the present invention, the temperature of the outlet 302 is set at -25 to -5 ° C from Tg, and the temperature of Tg is -20 to ± 0 ° C in the actual pulverized state. Then, the pulverization is performed so that the resin covers a part of the magnetic iron oxide present on the surface of the magnetic toner after the pulverization. As a result, the distribution of the raw materials on the surface of the magnetic toner tends to have an appropriate value, and the hydrophobic characteristic characteristic of the present invention can be imparted to the magnetic toner.

The magnetic iron oxide of the present invention has a number average particle size
It is preferably from 0.05 to 1.00 μm, more preferably from 0.10 to 0.40, in view of the dispersibility of the magnetic toner in the binder resin and the uniformity of charging. When the number average particle diameter of the magnetic iron oxide is larger than 1.00 μm, the number of the magnetic iron oxide particles contained in the toner is reduced, so that the dispersion of the magnetic iron oxide in the binder resin is biased. It is easy to lose the uniformity of charging. When the number average particle diameter of the magnetic iron oxide is smaller than 0.05 μm, the adhesive force between the magnetic iron oxide particles is increased, and the dispersibility in the binder resin may be deteriorated.

The shape of the magnetic iron oxide of the present invention is preferably an octahedron, a hexahedron or a substantially spherical shape, and particularly preferably a substantially spherical shape.

The magnetic iron oxide of the present invention has a BET specific surface area of ² to 40 m ² / g, preferably 4 to ²⁰ m ² / g. If the BET specific surface area is less than 2 m ² / g, the chargeability of the magnetic toner may be insufficient.
If the BET specific surface area exceeds 40 m ² / g, the dispersion of the magnetic iron oxide may be insufficient.

The magnetic iron oxide of the present invention has a magnetic characteristic of a saturation magnetization of 10 to 200 A under a magnetic field of 795.8 kA / m.
m ² / kg, more preferably 70-100 Am ² / kg,
The residual magnetization is 1 to 100 Am ² / kg, more preferably 2
Those having a coercive force of 1 to 30 kA / m, more preferably ² to 15 kA / m, are preferably used. By having such magnetic characteristics, the magnetic toner can obtain good developability in which image density and fog are balanced.

In the magnetic iron oxide of the present invention, the pH value and time are adjusted in the step of forming a magnetic iron oxide by oxidizing an iron salt into an iron colloid with an alkaline solution,
The heating conditions were changed, and Mg, Al, Si, P, S,
It can be adjusted by adding an aqueous solution of Zn or Zr.

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

The element α in the magnetic iron oxide used in the present invention basically exists inside and / or on the surface of the magnetic iron oxide and is unevenly distributed outside. Further, the element α2 is more unevenly distributed outside the magnetic iron oxide and also present more on the surface, so that various effects characteristic of the present invention can be exhibited. Since the content of the element α of the magnetic iron oxide of the present invention increases inclining toward the surface of the magnetic iron oxide, the effects characteristic of the present invention can be exhibited.

The magnetic iron oxide having the element α or β according to the present invention is produced, for example, by the following method. A predetermined amount of Mg, Al, Si, P, S, Zn, Ti,
After adding a salt, oxide, hydroxide, oxo acid salt or the like of one or more elements α or β selected from Zr, an alkali such as sodium hydroxide is added in an equivalent amount or more to the iron component, and the An aqueous solution containing ferrous iron is prepared. PH of the prepared aqueous solution is 7 or more (preferably 8 to 10)
The ferrous hydroxide is oxidized while the aqueous solution is heated to 70 ° C. or higher while maintaining the temperature, and a seed crystal serving as a core of the magnetic iron oxide particles is first generated.

Next, an aqueous solution containing the first equivalent of ferrous sulfate based on the previously added amount of alkali is added to the slurry-like liquid containing 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. It is preferable that the pH of the solution is adjusted at the end of the oxidation reaction so that a predetermined amount of another metal compound is unevenly distributed on the surface of the magnetic iron oxide particles. At this time, when the above-mentioned salt of the element α is added, various elements α can be present in large amounts near the surface of the magnetic iron oxide.

Salts of the elements α or β used for addition include sulfates, nitrates, carbonates, aluminates, silicates, oxoacid salts of phosphorus, oxoacid salts of sulfur, titanates and zirconates. And the like, and chlorides, oxides, hydroxides and the like are used. Examples of the silicate that can be used for addition include sodium silicate and potassium silicate.

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

The method of 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, the magnetic iron oxide particles having the element α are mainly composed of spherical particles formed of a curved surface having no plate-like surface, as observed by transmission electron micrographs. It is preferable to produce a magnetic iron oxide containing almost no particles and use the magnetic iron oxide in a magnetic toner.

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

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.
The content is preferably 0 to 200 parts by mass, more preferably 30 to 150 parts by mass. Content of magnetic iron oxide is 2
If the amount is less than 0 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, each physical property of the magnetic iron oxide is measured by the following methods.

(1) Particle Size and Shape of Magnetic Iron Oxide Transmission Electron Microscope (TEM) H-700H, H-80
0, H-7500 (all manufactured by Hitachi, Ltd.) or a scanning electron microscope (SEM) S-800 or S-4700 (both manufactured by Hitachi, Ltd.), and the magnetic iron oxide was 20,000.
Images can be taken at a magnification of 0 to 100,000, and the sample can be observed at an arbitrary magnification as a printing magnification of 1 to 5 times.
As for the particle size, 100 particles having a particle size of 0.03 μm or more are randomly selected, the maximum length (μm) of each particle is measured, and the average is defined as the number average particle size.

(2) Determination of Element α or β Present in Magnetic Iron Oxide In the present invention, element α (M
g, Al, Si, Zn, Ti, Zr) or the element β
The (S, P) content (based on magnetic iron oxide), the dissolution rate of the elemental iron and the dissolution rate R of the element α or β other than iron with respect to the dissolution rate of the iron element are determined by the following methods. Can be. For example, about 3 in a 5-liter beaker
Add 1 liter of deionized water and heat to 45-50 ° C in a water bath. About 25 g of magnetic iron oxide slurried with about 400 ml of deionized water is precisely weighed,
While washing with 00 ml of deionized water, add to the 5 liter beaker with the deionized water.

Next, while maintaining the temperature at about 50 ° C. and the stirring speed at about 3.33 s ⁻¹ (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 20 ml of the sample is sampled several times from the start of dissolution until it is completely dissolved and clear, filtered through a 0.1 μ membrane filter, and the filtrate is collected. The filtrate is subjected to plasma emission spectroscopy (ICP) to quantify the iron element and the element α or β other than the iron element.

The iron element dissolution rate is calculated by the following equation.

Iron element dissolution rate (% by mass) = (a / b) × 100 a: concentration of iron element in a collected sample (mg / l) b: concentration of iron element when completely dissolved (mg / l)

The content of metal elements other than iron on the basis of 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 R of the element α (β) is calculated by the following equation. Element α (β) dissolution rate R (%) = (f / g) × 100 f: Content (% by mass) of element α (β) in each iron element dissolution rate g: Element α when completely dissolved β) content (% by mass)

The solubility R of the element α or β existing when the iron dissolution rate of the magnetic iron oxide is up to 20% by mass is determined as follows. Based on the time when the dissolution rate of the iron element reaches 100% by mass, the dissolution rate of the iron element is calculated to be 20% by mass.
Find the time you arrived at. Based on this, the frequency of samples around 20% by mass was increased in the process of dissolving the magnetic iron oxide,
From the collected samples, several samples corresponding to the iron element dissolution rate of 20% by mass were selected, and the content f of the element α or β present when the iron element dissolution rate was up to 20% by mass was calculated or shown in the graph. From this, and the total content g of the element α present in the magnetic iron oxide, the dissolution rate R of the element α or β is determined according to the above formula.

(2) BET Specific Surface Area The BET specific surface area is determined by a BET multipoint method using a fully automatic gas adsorption amount measuring apparatus: Autosorb 1, manufactured by Yuasa Ionics Co., Ltd., using nitrogen as the adsorbed gas. In addition, as pretreatment of a sample, degassing is performed at 50 ° C. for 1 hour.

(3) Magnetic Characteristics of Magnetic Iron Oxide The magnetic characteristics of the magnetic iron oxide are described in "Vibration sample type magnetometer VSM-
3S-15 "(manufactured by Toei Industry Co., Ltd.)
It is a value measured under 5.8 kA / m.

The magnetic toner of the present invention has at least one endothermic peak in a DSC curve measured by a differential scanning calorimeter (DSC) when the temperature is raised, and the endothermic peak is 60 to
It is preferably present at 125 ° C, preferably 65-120 ° C, more preferably 70-115 ° C. Although two or more endothermic peaks may be present, in that case, 60 to 1
It preferably has at least one endothermic peak at 25 ° C. From the DSC curve at the time of the temperature rise, the melting behavior of the magnetic toner due to heat absorption can be seen. Endothermic peak 60
When the temperature is in the range of ~ 125 ° C, the viscosity is sufficiently lowered when the magnetic toner is heated and melt-kneaded, the magnetic iron oxide can be dispersed well, and the chargeability of the magnetic toner is stabilized.

The endothermic peak of the magnetic toner of the present invention is caused by the wax contained in the magnetic toner, and a desired endothermic peak can be obtained by selecting an appropriate wax and incorporating it into the magnetic toner. . The wax capable of imparting such an endothermic peak to the magnetic toner is easy to impart high hydrophobicity to the magnetic toner on the surface of the magnetic toner due to its melting property, and the wettability characteristic of the present invention is applied to the magnetic toner. Can be provided.

In the present invention, the DSC curve of the magnetic toner is represented by a differential scanning calorimeter (DSC measuring device), for example, DS
C-7 (PerkinElmer) and DSC2920 (T
AS Instruments Japan Co., Ltd.)
The measurement is performed according to D3418-82. The DSC curve is
After raising and lowering the temperature once and taking the previous history, the rate of temperature increase is 10 ° C.
The DSC curve measured when the temperature is raised at a rate of / min is used. The peak accompanying the glass transition point of the binder resin is distinguished.

The kind of the binder resin used in the present invention includes styrene resin, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural modified phenol resin, and natural resin modified male. Examples include 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, and petroleum resin. Of these, styrene-based copolymer resins and polyester resins are preferably used.

As comonomers for the styrene monomer of the styrene copolymer, styrene derivatives such as vinyltoluene, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-acrylic acid 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.

The polymerization method that 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 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 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-di- (t-butylperoxy) hexane, 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- Butylperoxycyclohexyl) propane, 2,2-t-butylperoxyoctane, n-butyl-4,4-di (t-butylperoxy) valerate, α, α′-bis (t-butylperoxydiisopropyl) Polyfunctional polymerization initiator having a functional group having a polymerization initiation function such as two or more peroxide groups in one molecule such as benzene and various polymer oxides, diallyl peroxydicarbonate, t
In one molecule such as -butylperoxymaleic acid, t-butylperoxyallyl carbonate and t-butylperoxyisopropyl fumarate, both a functional group having a polymerization initiation function such as a peroxide group and a polymerizable unsaturated group are contained. Selected from multifunctional polymerization initiators having the formula:

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, organic peroxides such as benzoyl peroxide, dicumyl peroxide, t-butylperoxycumene and di-t-butyl peroxide; azobisisobutyronitrile, diazoaminoazobenzene and the like. Azo and diazo compounds are exemplified.

These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator. However, in order to maintain the efficiency of the polyfunctional polymerization initiator properly, 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 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.

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;

[0094]

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):

[0096]

Embedded image

As the divalent acid component, for example, phthalic acid,
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 and a trivalent or higher valent acid component which function as a crosslinking component.

The trihydric or higher polyhydric alcohol component includes
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.

The polyvalent carboxylic acid component having three or more valences in the present invention 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;

[0101]

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 can also be obtained by generally known condensation polymerization.

The toner of the present invention preferably contains a charge control agent.

The following compounds can be used to control the toner to be negatively charged.

Organic metal complexes and chelate compounds are effective, and examples thereof include metal complexes of monoazo metal complexes, metal complexes of acetylacetone, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acids. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives of bisphenol.

Among them, an azo metal complex represented by the following formula (1) is preferable.

[0108]

Embedded image [Wherein, M represents a coordination center metal, and Sc, Ti, V, C
r, Co, Ni, Mn or Fe. Ar is an aryl group, is an aryl group such as a phenyl group and a naphthyl group, and may have a substituent. In this case, the substituent includes a nitro group, a halogen group, a carboxyl group,
Anilide group and alkyl group having 1 to 18 carbon atoms, 1 carbon atom
There are ~ 18 alkoxy groups. X, X ', Y and Y' are -O-, -CO-, -NH-, -NR- (R is
To 4 alkyl groups). C ⁺ represents a counter ion, and represents hydrogen, sodium, potassium, ammonium, aliphatic ammonium or a mixed ion thereof. ]

In particular, the central metal is preferably Fe or Cr, the substituent is preferably a halogen, an alkyl group or an anilide group, and the counter ion is preferably hydrogen, an alkali metal, ammonium or aliphatic ammonium. A mixture of complex salts having different counter ions is also preferably used.

A basic organometallic complex represented by the following formula (2) is also preferred as a charge control agent imparting negative chargeability.

[0111]

Embedded image

The following compounds control the toner to be positively charged.

Nigrosine modified with nigrosine and fatty acid metal salt; tributylbenzylammonium-1-
Quaternary ammonium salts such as hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts, which are analogs thereof, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof , (As the lakening agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.);
Metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guanidine compounds; and imidazole compounds. These can be used alone or in combination of two or more.
Among these, a triphenylmethane compound and a quaternary ammonium salt whose counter ion is not halogen are preferably used. The following equation (3)

[0114]

Embedded image [Wherein R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably C ₁ -C ₄ )] A copolymer with a polymerizable monomer such as styrene, acrylate or methacrylate described above can be used as a positive charge control agent. In this case, the homopolymer and the copolymer have a function as a charge control agent and a function as (all or part of) a binder resin.

Particularly, the compound represented by the following formula (4) is preferable as the toner positive charge control agent of the present invention.

[0116]

Embedded image [Wherein, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may be the same or different from each other, and include a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkyl group. Represents an aryl group. R ₇ , R ₈ and R ₉ may be the same or different from each other and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. A ^- is a sulfate ion,
Anions such as nitrate ion, borate ion, phosphate ion, hydroxyl ion, organic sulfate ion, organic sulfonate ion, organic phosphate ion, carboxylate ion, organic borate ion, and tetrafluoroborate are shown. ]

As a method for incorporating the charge control agent into the toner, there are a method of adding the charge control agent inside the toner particles and a method of adding the charge control agent externally. The use amount of these charge control agents is determined by the type of the binder resin, the presence or absence of other additives, the toner manufacturing method including the dispersion method, and is not limited to a specific one. Preferably, it is used in the range of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the binder resin.

The wax of the present invention can be used in a differential scanning calorimeter (D
SC) has at least one endothermic peak in the DSC curve at the time of temperature rise, wherein the endothermic peak is 60 to 12
5 ° C, preferably 65-120 ° C, more preferably 70 ° C
Preferably it is present at ~ 115 ° C. Endothermic peak is 2
There may be more than one, but in that case, 60 to 125
It is preferred to have at least one endothermic peak at ° C. When the wax has an endothermic peak in the above temperature range, the magnetic toner can be provided with a preferable endothermic characteristic.

The wax contained in the magnetic toner of the present invention includes low-molecular-weight polyethylene, low-molecular-weight polypropylene,
Aliphatic hydrocarbon waxes such as olefin copolymers, microcrystalline wax, paraffin wax and Fischer-Tropsch wax; aliphatic hydrocarbon wax oxides such as oxidized polyethylene wax or block copolymers thereof; carnauba wax ,
Waxes mainly containing fatty acid esters such as montanic acid ester waxes; and those obtained by partially or entirely deoxidizing fatty acid esters such as deoxidized carnauba wax. In addition, palmitic acid, stearic acid,
Saturated straight-chain fatty acids such as 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; stearic alcohol, aralkyl alcohol, behenyl alcohol; Saturated alcohols such as carnaubavir alcohol, seryl alcohol, melisyl alcohol, or long-chain alkyl alcohols having a longer-chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amide, oleic acid amide, lauric acid Fatty acid amides such as amides; saturated fatty acid bisamides such as methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide, and ethylenebisoleic acid amide De, hexamethylene bis oleic acid amide, N, N'-dioleyl adipic acid amide,
Unsaturated fatty acid amides such as N, N'-dioleyl sebacamide; m-xylene bisstearic acid amide;
Aromatic bisamides such as N, N'-distearyl isophthalamide; waxes obtained by grafting an aliphatic hydrocarbon wax with a vinyl monomer such as styrene or acrylic acid; fatty acids such as behenic acid monoglyceride And polyhydric alcohols; and methyl ester compounds having a hydroxy group obtained by hydrogenating vegetable fats and oils.

Examples of the wax preferably used include a paraffin wax, a low-molecular-weight olefin polymer obtained by radical polymerization of an olefin under a high pressure or a low-pressure polymerization using a Ziegler catalyst, a metallocene catalyst or another catalyst; An olefin polymer obtained by thermal decomposition; a low-molecular-weight olefin polymer produced as a by-product when polymerizing an olefin polymer is separated and purified; obtained from a synthesis gas composed of carbon monoxide and hydrogen derived from coal or natural gas by the Arage method A wax obtained by extracting and fractionating a specific component from a hydrocarbon distillation residue or a synthetic hydrocarbon obtained by hydrogenating the hydrocarbon is used. An antioxidant may be added to these waxes. Further, waxes formed of linear alcohols, fatty acids, acid amides, esters or montan derivatives are mentioned. It is also preferable that impurities such as fatty acids have been removed in advance. Further, a long-chain alkyl alcohol having a hydroxyl group at a terminal having a carbon number of up to about several hundreds is also preferable. Further, those obtained by adding an alkylene oxide to an alcohol are also preferably used.

Among them, preferred are those obtained by polymerizing olefins such as paraffin wax, ethylene and propylene, and by-products at this time, such as Fischer-Tropsch wax and those having a hydrocarbon of up to several thousands of carbon atoms as a base. Hydrocarbon wax is preferred.

Then, from these waxes, the waxes are subjected to press sweating, solvent method, vacuum distillation, supercritical gas extraction, fractional crystallization (for example, melt liquid crystal precipitation and crystal filtration), etc., to obtain waxes having different molecular weights. A wax that has been fractionated and has a sharp molecular weight distribution is more preferable because the proportion of components in the necessary melting behavior range increases.

At this time, the wax is more preferably a hydrocarbon wax so as not to impair the releasability. Further, in order to easily exert the wettability of the present invention, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-α olefin copolymer, propylene-α olefin copolymer, polymerized with a metallocene catalyst,
Olefin copolymers, polyolefins, Fischer-Tropsch wax and paraffin wax are preferably used.

The molecular weight distribution of the wax was such that Mw / Mn was 3.
It is preferably 0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less.

It is effective that the wax used in the present invention is added in an amount of 0.1 to 15 parts by mass, preferably 0.5 to 12 parts by mass based on 100 parts by mass of the binder resin. It is also preferable to use a plurality of waxes in combination.

The toner of the present invention may contain a colorant, and the colorant used may be any suitable pigment or dye. Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient to maintain the optical density of the fixed image.
0.1 to 20 parts by mass, preferably 0.2 to 0 parts by mass
The addition amount of 10 to 10 parts by mass is good. Examples of the dye include an azo dye, an anthraquinone dye, a xanthene dye, and a methine dye. The dye is added in an amount of 0.1 to 20 parts by mass, preferably 0.3 to 10 parts by mass, based on 100 parts by mass of the binder resin.

The magnetic toner of the present invention contains an inorganic fine powder. The inorganic fine powder is preferably externally added to the magnetic toner particles. The inorganic fine powder is preferably a hydrophobic inorganic fine powder. Examples of the inorganic fine powder include silica fine powder, titanium oxide fine powder, alumina fine powder, and a hydrophobized product thereof. They are preferably used alone or in combination.

Examples of the silica fine powder include a dry method produced by vapor phase oxidation of a silicon halide and a dry method called fumed silica and a wet method produced from water glass and the like. Dry silica having few silanol groups and no production residue is preferable.

Further, the silica fine powder is preferably subjected to a hydrophobic treatment. The hydrophobization treatment is provided by chemically treating with an organosilicon compound that reacts or physically adsorbs with the silica fine powder. As a preferred method, there is a method in which fine silica powder produced by vapor-phase oxidation of a silicon halide compound is treated with a silane compound or simultaneously with a silane compound and treated with an organosilicon compound such as silicone oil.

Examples of the silane compound used for the hydrophobizing treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane. , Benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilanemercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, Dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinylte Tramethyldisiloxane, 1,
3-diphenyltetramethyldisiloxane is exemplified.

Examples of the organosilicon compound include silicone oil. Preferred silicone oils have a viscosity of about 30 to 1,000 mm at 25 ° C.
² / s is used. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil are preferred.

A particularly preferred method is a method of treating with dimethyl silicone oil. Silica fine powder that has been hydrophobized with dimethyl silicone oil has moderate hydrophobicity and excellent slipperiness, so the magnetic toner will fuse to the developing sleeve during long-term use and the image density will decrease. Can be effectively prevented. It is particularly effective when used for a magnetic toner having a high chargeability, such as the magnetic toner of the present invention.

In the method of treating with silicone oil, silica fine powder treated with a silane compound and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silicone oil as a base may be sprayed. It is good depending on the method. 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.

As a preferable hydrophobic treatment of the silica fine powder, there is a method of preparing by treating with a silane compound and then with a silicone oil.

It is also preferable that the above-mentioned silica fine powder is subjected to a hydrophobic treatment to fine titanium oxide powder and fine alumina powder, as in the case of silica.

If necessary, additives other than silica fine powder, alumina fine powder or titanium oxide fine powder may be added to the toner of the present invention.

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 fine resin particles have an average particle size of 0.1.
Those having a thickness of 03 to 1.0 μm are preferred. As the polymerizable monomer constituting the resin, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene derivatives; acrylic acid; methacrylic acid; methyl acrylate , Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate And acrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, and styrene methacrylate. Lil, phenyl methacrylate, dimethylaminoethyl methacrylate, such as methacrylic acid esters of diethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, and the like monomers acrylamide.

The polymerization method includes suspension polymerization, emulsion polymerization and soap-free polymerization. More preferably, particles obtained by soap-free polymerization are good.

Other fine particles include lubricants such as fluororesin, zinc stearate and polyvinylidene fluoride (polyvinylidene fluoride is preferred); abrasives such as cerium oxide, silicon carbide and strontium titanate (particularly titanic acid) Strontium is preferred); an anti-caking agent; and a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide, and tin oxide. Further, a small amount of white fine particles and black fine particles having a polarity opposite to that of the toner may be used as a developing property improver.

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

The weight average particle size and the particle size distribution of the toner are measured by using a Coulter counter method. For example, a Coulter Multisizer (manufactured by Coulter) can be used. The electrolyte is 1% Na using primary grade sodium chloride.
Prepare a Cl 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
0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant in 50 ml,
Further, 2 to 20 mg of a measurement sample is 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 particle size of 2.00 μm or more were measured by using the measuring device with a 100 μm aperture as the aperture. Calculate the volume distribution and number distribution.
Then, the weight-based weight average particle diameter (D ₄ ) obtained from the volume distribution according to the present invention is calculated.

The channels are 2.00 to 2.52
less than 2.5 μm; less than 2.52 to 3.17 μm;
4. less than 4.00 μm; 4.00 to less than 5.04 μm;
04 to less than 6.35 μm; 6.35 to less than 8.00 μm; 8.00 to less than 10.08 μm; 10.08 to 1
2.70 μm or less; 12.70 to less than 16.00 μm;
16.00 to less than 20.20 μm; 20.20 to 25.
Less than 40 μm; 25.40 to less than 32.00 μm; 3
13 channels of 2.00 to less than 40.30 μm are used.

The method for producing the toner of the present invention includes the following.
After sufficiently mixing the above-mentioned toner constituent materials with a ball mill or other mixer, the mixture is well kneaded using a heat kneader such as a hot roll kneader or an extruder, and after cooling and solidifying, is mechanically pulverized to obtain a pulverized powder. A method of obtaining a toner by classification is preferable. Another method is a polymerization method in which a predetermined material is mixed with a monomer to constitute a binder resin to form an emulsified suspension and then polymerized to obtain a toner. In the microcapsule toner, a method in which a predetermined material is contained in a core material or a shell material, or both of them; a method in which a constituent material is dispersed in a binder resin solution and then spray-dried to obtain a toner. Further, if desired, the desired additive and the toner particles are sufficiently mixed by a mixer such as a Henschel mixer to produce the toner of the present invention.

For example, as a mixer, a Henschel mixer (Mitsui Mining); a super mixer (Kawata); a ribocorn (Okawara Seisakusho); a Nauta mixer, a turbulizer, a cyclomix (Hosokawa Micron); Spiral Pin Mixer (manufactured by Taiheiyo Kiko Co., Ltd.); Reedige Mixer (manufactured by Matsubo Co., Ltd.). Kneading machines include KRC Kneader (manufactured by Kurimoto Tekkosho); Mold extruder (manufactured by Toshiba Machine Co., Ltd.); TEX 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); knee Decks (manufactured by Mitsui Mining Co., Ltd.); MS-type pressurized kneader, nider ruder (manufactured by Moriyama Seisakusho); Banbury mixer (manufactured by Kobe) And a pulverizer such as a counter jet mill, a micron jet, an inomizer (manufactured by Hosokawa Micron); an IDS-type mill, a PJM jet pulverizer (manufactured by Nippon Pneumatic) and a cross jet mill (Kurimoto Tekko) Ullmax (Nisso Engineering); SK Jet
O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Super Rotor (manufactured by Nisshin Engineering Co., Ltd.);
Classifiers include Crasheal, Micron Classifier, Spedick Classifier (manufactured by Seishin Enterprise); Turbo Classifier (manufactured by Nisshin Engineering); micron separator, turboplex (ATP), TSP separator (manufactured by Hosokawa Micron) Elbow Jet (manufactured by Nippon Steel Mining), dispersion separator (manufactured by Nippon Pneumatic), Y
M microcut (manufactured by Yasukawa Shoji Co., Ltd.); a granulator includes a roller compactor (manufactured by Turbo Kogyo Co., Ltd.); and a sieving device used for sifting coarse particles, etc., includes Ultrasonic (Akira). Sakae Sangyo Co., Ltd.);
Resona sieve, gyro shifter (manufactured by Tokuju Kosakusho);
Vibrasonic System (Dalton); Sonic Clean (Shinto Kogyo); Turbo Screener (Turbo Kogyo); Microshifter (Makino Sangyo);

[0146]

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

(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 in the magnetic iron oxide was about 0.6%. Thereafter, a caustic soda solution was mixed to prepare an aqueous solution containing ferrous hydroxide. Air is blown in while adjusting the pH of the aqueous solution, and an oxidation reaction is performed at 80 to 90 ° C.
A slurry liquid for forming a seed crystal was prepared.

When the formation of seed crystals was confirmed, an aqueous solution of ferrous sulfate and an aqueous solution of zinc sulfate were appropriately added to the slurry, and air was blown while adjusting the pH of the slurry to proceed the oxidation reaction. In the meantime, while examining the progress rate of the reaction while examining the concentration of unreacted ferrous hydroxide, the distribution of Si and Zn in the magnetic iron oxide is adjusted by appropriately adding zinc sulfate and further adjusting the pH of the aqueous solution. Control and complete the oxidation reaction. The generated magnetic iron oxide particles are washed by a conventional method, filtered,
Drying and pulverization gave magnetic iron oxide 1.

Table 1 shows the contents of Si and Zn and the dissolution rate R of Si and Zn with respect to the dissolution rate of iron element based on the magnetic iron oxide in the obtained magnetic iron oxide 1. FIG. 2 shows the dissolution rate R of Si and Zn with respect to the dissolution rate of iron element.
The dissolution rate R of Si and Zn existing up to the iron element dissolution rate of 20% by mass was obtained from the graph shown in FIG.

(Production Examples 2 to 14) Production Examples 2 to 14 were conducted except that the amount, timing and / or type of addition of the salt of the other element α or β were changed to obtain magnetic iron oxide having the physical properties shown in Table 1. In the same manner as in Example 1, magnetic iron oxides 2 to 14 were obtained.

Example 1 100 parts by mass of styrene-n-butyl acrylate copolymer (Tg 60 ° C.) 100 parts by mass of magnetic iron oxide 1 of Production Example 1 2 parts by mass of monoazo iron complex 2 parts by mass Fischer-Tropsch wax (DSC) Endothermic peak 105 ° C) 4 parts by mass The mixture was premixed with a Henschel mixer, and then
The mixture was melted and kneaded with a biaxial extruder heated to 0 ° C., and the cooled kneaded material was roughly pulverized with a hammer mill to obtain a roughly pulverized magnetic toner. The obtained coarsely pulverized material was finely pulverized by mechanical pulverization using a turbo mill (manufactured by Turbo Kogyo Co., Ltd.) based on the condition table in Table 3 while adjusting the air temperature. Fine powder, ultra fine powder and coarse powder are simultaneously strictly classified and removed by a multi-segmentation classifier utilizing the effect (Nippon Mining Co., Ltd. Elbow Jet Classifier), and the weight average particle diameter (D ₄ )
6.6 μm negatively chargeable magnetic toner particles were obtained. Further, the fine powder, ultra-fine powder and coarse powder generated in the classification are granulated by a roller compactor (manufactured by Turbo Kogyo Co., Ltd.), and 10% by mass of the entire raw material is added to the raw material. Weight average particle size (D ₄ ) 6.6 depending on the method
μm negatively-charged magnetic toner particles were obtained.

100 parts by mass of the magnetic toner particles and 1.2 parts by mass of hydrophobic silica fine powder treated with hexamethyldisilazane and then treated with dimethylsilicone oil were mixed with a Henschel mixer to form a negatively-charged magnetic powder. Toner 1 was prepared. FIG. 1 shows a graph of the methanol concentration of the magnetic toner 1 with respect to the transmittance of light having a wavelength of 780 nm.

[Examples 2 to 11 and Comparative Examples 1 to 7] Example 1 was repeated except that the magnetic iron oxide and the wax used were changed as shown in Table 2 and the milling conditions of the turbo mill were changed as shown in Table 3. In the same manner as in the above, magnetic toners 2 to 18 were obtained. Next, the prepared magnetic toner was evaluated by the following method. Tables 4 and 5 show the evaluation results.

(Evaluation) Evaluation was performed using the toner thus obtained. The printout test was performed as follows, and the results are shown in Tables 4 and 5.

<Print-out test> High temperature and high humidity (30.
A printout test was performed using a commercially available printer iR-6000 (manufactured by Canon) in each environment of 0 ° C., 80% RH) and normal temperature and low humidity (23 ° C., 5% RH). The printout speed was 60 sheets (A4 landscape) per minute, and the obtained images were evaluated for the following items. The printout was performed in a situation where the exhaust fan was stopped and the temperature inside the machine was raised.

Image Density (Tables 4 and 5) 20,000 sheets of ordinary paper for copying machines (80 g / m ² ) intermittently (2 sheets / 10 seconds) under normal temperature and low humidity, and 20,000 sheets on both sides continuous under high temperature and high humidity The evaluation was made based on the change in image density of the printouts. At 10,000 sheets, printing was suspended, left in that environment for three days, and then resumed. The image density was measured using a “Macbeth reflection densitometer” (manufactured by Macbeth Co., Ltd.).
When the 10,000th sheet was restarted, the measurement was performed on the 20,000th sheet, and the five points were averaged.

Fog (Tables 4 and 5) The image density was measured by comparing the whiteness of the transfer paper measured by a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) with the whiteness of the transfer paper after printing solid white. Calculated at the timing.

Disturbance of toner coat on sleeve (toner carrying member) (Tables 4 and 5) In a normal temperature and low humidity (23 ° C., 5% RH) environment, 20,000 sheets were intermittently printed out at a rate of 2 sheets / 10 seconds. The surface of the sleeve was visually observed on the 10,000th and 20,000th sheets, and the degree of toner coating on the sleeve was evaluated. A: Uniform coat B: Disorder of Sazanami coat occurs at sleeve end C: Disturbance of Sazanami coat occurs or disappears, but does not appear in image D: A partially blotch-like toner coat defect occurs,
Local solid density shading and deterioration of fog are observed. E: Blotches are generated on the entire surface and the image is disturbed.

When 20,000 sheets were printed out continuously on both sides in a high-temperature, high-humidity (30.0 ° C., 80% RH) environment, the surface of the sleeve was visually observed, and the toner coat on the sleeve and the solid image were removed. The evaluation was based on the degree of influence. A: Uniform coating B: The coating amount is slightly reduced at 10,000 sheets, and the density of the solid image is slightly reduced, but is recovered by pausing. C: The coating amount is slightly reduced at 10,000 sheets, and the density of the solid image is slightly reduced. D: The amount of coating decreases after 10,000 copies and the density of the solid image decreases, but it takes time to recover from the pause. E: The coating amount decreases after 10,000 copies and the density of the solid image decreases. Some reduction, but little recovery from pause

Image scattering (Tables 4 and 5) 20,000 sheets intermittently (2 sheets / 10 seconds) under normal temperature and low humidity,
Under high temperature and high humidity, image scattering of 20,000 printouts continuous on both sides was evaluated. 10,000th sheet, 200
It was measured on the 00th sheet. A: An image with little image scattering even by magnifying observation B: Scattering is observed by magnifying observation but not visible C: Characters slightly blur due to scattering D: Line thickness becomes uneven due to scattering E: Due to splattering, some fine characters are crushed

[0161]

[Table 1]

[0162]

[Table 2]

[0163]

[Table 3]

[0164]

[Table 4]

[0165]

[Table 5]

[0166]

According to the present invention, it is possible to obtain a magnetic toner which maintains high developability and high image quality for a long period of use even in high-speed development under severe environments such as high temperature, high humidity, low humidity, or a high temperature inside the machine, and does not cause sleeve blotting. Can be provided.

[Brief description of the drawings]

FIG. 1 is a graph showing transmittance with respect to methanol concentration in a magnetic toner 1 of Example 1 of the present invention.

FIG. 2 is a graph showing the solubility R of each metal element α with respect to the iron element solubility in the magnetic iron oxide 1 of Example 1 of the present invention.

FIG. 3 is a schematic sectional view of a mechanical pulverizer that can be used in the pulverizing step of the magnetic toner of the present invention.

FIG. 4 is a schematic cross-sectional view taken along a line DD ′ in FIG. 3;

FIG. 5 is a perspective view of the rotor shown in FIG. 3;

Continued on the front page (72) Inventor Tsutomu Onuma 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kaori Hiratsuka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F term (reference) 2H005 AA02 AA06 CA14 CB03 EA03 EA10

Claims (9)

[Claims] 1. A magnetic toner containing at least a binder resin, a magnetic iron oxide and a wax, wherein the magnetic toner has a wettability with respect to a methanol / water mixed solvent as measured by a transmittance of light having a wavelength of 780 nm. The methanol concentration is 65 to 80 when the transmittance is 80%.
%, And the methanol concentration at a transmittance of 10% is within a range of 65 to 80% by volume. The magnetic iron oxide is selected from Mg, Al, Si, Zn, Ti, and Zr. Is a magnetic iron oxide having 0.10 to 4.00 mass% of at least one element α based on the magnetic iron oxide, and when the iron element dissolution rate in the magnetic iron oxide is 20%,
A magnetic toner, wherein the dissolution rate R of the element α is 44% or more and 100% or less. 2. The magnetic iron oxide according to claim 1, wherein the element α1 is Mg,
At least one element α selected from Al, Si, and Zn
1 is 0.10 to 4.00% by mass based on the magnetic iron oxide, and when the iron element solubility in the magnetic iron oxide is 20%, the solubility R1 of the element α1 is 44% or more. 100% or less, at least one element α2 different from the element α1 selected from Mg, Al, Si, Zn
Is 0.10 to 4.00 mass% based on the magnetic iron oxide, and when the iron element dissolution rate in the magnetic iron oxide is 20%, the solubility R2 of the element α2 is 44% or more and 100% or more. % Of the magnetic toner according to claim 1. 3. The magnetic iron oxide according to claim 1, wherein the element α1 is Mg,
At least one element α selected from Al, Si, and Zn
1 is 0.10 to 4.00% by mass based on the magnetic iron oxide, and when the iron element solubility in the magnetic iron oxide is 20%, the solubility R1 of the element α1 is 44% or more. 100% or less, and at least one element β selected from S and P as the element β is 0.10 based on magnetic iron oxide.
2. The magnetic toner according to claim 1, wherein the magnetic iron oxide has a content of from about 4.0% to 4.00% by mass. 4. The element α1 is Si, and the element α2 is M
The magnetic toner according to claim 2, wherein the magnetic toner is at least one element selected from g, Al, and Zn. 5. The element α1 is Si, and the element β is P, S
The magnetic toner according to claim 3, wherein the magnetic toner is at least one element selected from the group consisting of: 6. The magnetic iron oxide is a magnetic iron oxide containing 0.20 to 3.50% by mass of Si (element α1) based on the magnetic iron oxide, and a dissolution rate of the iron element in the magnetic iron oxide. When 20%, the dissolution rate R1 of Si (element α1) is 45%
Not less than 90% and at least one element α2 selected from Mg, Al and Zn is 0.10% based on magnetic iron oxide.
A magnetic iron oxide having an iron content of 20% to 3.00% by mass.
5. The magnetic toner according to claim 2, wherein the dissolution rate R2 of the magnetic toner is 50% or more and 100% or less. 7. A dissolution rate R1 and a dissolution rate R2 of said magnetic iron oxide.
7. The magnetic toner according to claim 2, wherein R2> R1. 8. The magnetic toner according to claim 1, wherein the wax is a hydrocarbon wax. 9. A differential scanning calorimeter (DS) for the magnetic toner.
C) has at least one endothermic peak in the DSC curve at the time of temperature rise measured according to C), and the endothermic peak is 60 to 125
The magnetic toner according to any one of claims 1 to 8, wherein the magnetic toner exists at a temperature of ° C.