JP5159497B2 - Magnetic toner - Google Patents

Description

  The present invention relates to a magnetic toner used in an image forming method such as an electrophotographic method, an electrostatic printing method, and a toner jet method.

As the technical direction of image forming apparatuses in recent years, in addition to high definition, high quality, and high image quality, further high speed and long-term high reliability are required. In particular, cartridge-type printers are becoming smaller in size and can be installed anywhere, so that they are used in various environments and are required to exhibit stable performance over a long period of time when used in various environments.
In the case of a magnetic toner used for a one-component development system, it is often used in a cartridge type printer. It may cause problems such as fluctuation or deterioration of various required characteristics.

  The magnetic iron oxide contained in the toner particles is exposed to the toner particle surface, so the magnetic iron oxide properties can affect the properties of the magnetic iron oxide when used after being stored for a long time in a high temperature and high humidity environment. It tends to appear remarkably. In particular, toner deterioration due to long-term use in a high-temperature and high-humidity environment, a decrease in density after standing for a long time, and poor cleaning are likely to occur in a toner after long-term storage in a high-temperature and high-humidity environment. Also, if a cartridge stored for a long time in a high-temperature, high-humidity environment without air conditioning equipment is brought into a room with air conditioning equipment and printed immediately, the air with a large amount of water in the toner container is rapidly cooled, causing condensation, When a uniform image pattern is output, there may occur an image defect of a phenomenon (hereinafter referred to as white haze) in which a toner is not developed in a circular shape having a size of about several mm to 10 mm.

  Patent Document 1 contains 0.10 to 1.00% by mass of Si, and there is a coprecipitate of silica and alumina on the surface, and Fe, Ti, Zr, Si, Al on the coprecipitate. A magnetic particle powder to which oxide particles or hydrated oxide particles of an element selected from the above are fixed is disclosed. However, even if Ti elements are contained in the magnetic particles by this method, Ti elements are present only on the surfaces of the magnetic particles, so that the Ti elements are easily detached from the surfaces of the magnetic particles, and are likely to deteriorate with long-term use.

  Patent Document 2 discloses iron oxide particles characterized by being coated with a composite iron oxide layer of Ti and Fe. However, since the distribution of Ti from the central part of the iron oxide particles to the surface is not controlled, when the toner is stored for a long time in a high-temperature and high-humidity environment, the toner deteriorates and the density tends to decrease.

  Patent Document 3 discloses a toner containing at least Si, Zn, and Ti and containing magnetic iron oxide that defines the respective dissolution rates when 5% is dissolved from the surface of the magnetic iron oxide. Yes. However, there are too many Ti elements present on the surface of the magnetic iron oxide, and the mechanical stress due to long-term use may cause the Ti element to deviate from the magnetic iron oxide, resulting in a decrease in concentration.

  In Patent Document 4, the silicon component is continuously contained from the center of the particle to the surface, and from among Zn, Mn, Cu, Ni, Co, Cr, Cd, Al, Sn, Mg, and Ti bonded to the silicon component. The outer shell is coated with a metal compound composed of at least one selected metal component, and the outer shell and the inner shell have a higher concentration of the metal component with respect to Fe in the outer shell and the surface layer. Magnetite particles having a gradient so as to be higher are disclosed.

Patent Document 5 discloses iron oxide particles characterized in that core particles from which a silicon component is exposed are coated with an Al component.
These attempts compare the abundance of elements when 20% and 40% Fe are dissolved from the magnetic iron oxide surface. However, when used in magnetic toners, the combination with toner properties such as fluidity is important. Improvement of magnetic iron oxide alone is not sufficient to improve the performance when the toner is used after long-term storage. there were.

  On the other hand, the flowability of the toner greatly affects the developing property and cleaning property of the magnetic toner and the toner deterioration due to long-term use. Highly fluid toner tends to flow due to stirring in the developing device and is difficult to deteriorate because the force received from the stirring member is dispersed. However, the toner is not easily rubbed and tends to take a long time to be charged. . On the other hand, although the toner having low fluidity has a quick rise in charge, it easily deteriorates, and also, since it hardly aggregates and flows even in the cleaner container, cleaning failure tends to occur. In particular, since the characteristics of magnetic iron oxide greatly affect the charging of the magnetic toner, it is necessary to precisely control the characteristics of the magnetic iron oxide and the fluidity of the magnetic toner.

Patent Documents 6 and 7 disclose magnetic toners having specific fluidity. However, these technologies do not describe the relationship between the characteristics of magnetic iron oxide and the fluidity of the magnetic toner, and the performance when the toner is used after being stored for a long time in a high temperature and high humidity environment is sufficient. Not considered.
As described above, there is a strong demand for the development of a magnetic toner that can exhibit stable performance even when used for a long period of time in various environments and conditions.
JP-A-7-240306 JP 2004-161551 A JP 2004-354810 PR Patent No. 3224774 Patent No. 3544316 JP 2007-148373 PR JP 2007-114752 PR

Therefore, the present invention has been made in view of the above-described circumstances in the prior art for the purpose of improving the drawbacks.
That is, an object of the present invention is to provide a magnetic toner that does not cause a decrease in density, a decrease in density due to standing for a long period of time, or a cleaning failure even after being stored for a long time in a high temperature and high humidity environment. There is.
It is a further object of the present invention to provide a magnetic toner that does not generate white fog even when the usage environment changes rapidly.

In order to achieve the above object, the present invention is as follows.
[1] A magnetic toner having toner particles containing at least a binder resin, wax, and magnetic iron oxide, and inorganic fine particles,
The magnetic iron oxide contains 0.30 mass% or more and 5.0 mass% or less of the Ti element with respect to the entire magnetic iron oxide,
The amount of Ti element (S-Ti) existing in a range where the Fe element dissolution rate is 10% or less is 40% or more and 70% or less of the total amount of Ti element contained in the magnetic iron oxide,
The amount of Ti element (M-Ti) existing in the range where the Fe element dissolution rate is greater than 10% and 50% or less is 10% or more and 40% or less of the total amount of Ti element contained in the magnetic iron oxide,
The amount of Ti element (C-Ti) existing in the range where the Fe element dissolution rate is greater than 50% and 100% or less is 1% or more and 20% or less of the total Ti element amount contained in the magnetic iron oxide,
(S-Ti), (M-Ti) and (C-Ti) satisfy the relationship of the following formulas (1) and (2),
Formula (1): (S—Ti) ≧ 2 × (C—Ti)
Formula (2): (M-Ti) ≧ 1.5 × (C—Ti)
[The dissolution rate of the Fe element is obtained by dissolving the magnetic iron oxide from the surface with an acid aqueous solution and setting the state in which the magnetic iron oxide is completely dissolved to 100% Fe element dissolution rate and dissolving the magnetic iron oxide in its entirety. The ratio of the amount of Fe element dissolved in the solution obtained in the process of dissolving the magnetic iron oxide from the surface with an acid aqueous solution to the total amount of Fe element when the amount of Fe element contained in the liquid is the total amount of Fe element (%). ]
The magnetic toner has a total torque E of rotational torque and vertical load in a non-ventilated state and a total sum Ea of rotational torque and vertical load in a vented state as measured by a powder flowability analyzer equipped with a rotary blade. A magnetic toner satisfying the following formulas (3) and (4):
Formula (3): 600 (mJ) ≦ E ≦ 1500 (mJ)
Formula (4): 500 (mJ) ≦ (E-Ea)
[In the above formulas (3) and (4), E (mJ) is a powder fluidity analyzer equipped with a rotary blade, and the propeller type blade is the peripheral speed of the outermost edge of the propeller type blade is 100 mm. While rotating at / sec, the magnetic powder is filled into the toner powder layer in the measuring container filled with the magnetic toner, and the measurement is started from a position of 100 mm from the bottom surface of the toner powder layer. Represents the sum of rotational torque and vertical load obtained when approaching the position. In addition, Ea (mJ) is a rotational torque and a vertical load measured in a ventilation state in which a porous plate is arranged at the bottom of the measurement container and dry air having a flow rate of 0.20 mm / sec is sent therefrom. Represents the sum. ]
[2] For the magnetic toner, the sum Ed of the rotational torque and the vertical load after the change from the aeration state to the non-aeration state, measured by a powder fluidity analyzer equipped with a rotary blade, The magnetic toner according to [1], wherein Formula (5) is satisfied.
Formula (5): 0.10 <(Ed / E) <0.70
[In the above formula (5), Ed (mJ) is a flow of 0.20 (mm / sec) dry air into the powder phase of the magnetic toner in the container, and the ventilation is stopped after measuring Ea. Then, the same measurement as E (mJ) was repeated four times, and the blade from the surface of the toner powder layer to the position of 10 mm from the bottom surface when the rotation speed of the fourth blade was 100 (mm / sec). Represents the sum of the rotational torque and the vertical load obtained when the is entered. ]
[3] The magnetic toner has a circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) of 0.200 to 1.000. The magnetic toner according to [1] or [2], wherein the average circularity analyzed by dividing into 800 in the circularity range is 0.940 or more.
[4] The magnetic toner contains a hydrotalcite compound in an amount of 0.01 parts by mass to 1.00 parts by mass with respect to 100 parts by mass of toner particles. The magnetic toner according to any one of the above.

According to the present invention, it is possible to provide a magnetic toner that does not cause a decrease in density, a decrease in density due to standing for a long period of time, or a cleaning failure even after being stored for a long time in a high temperature and high humidity environment. .
Furthermore, according to the present invention, it is possible to provide a magnetic toner that does not generate white fog even when the use environment is rapidly changed.

If the toner is stored in a high-temperature and high-humidity environment (an environment where the temperature is 40 ° C. or higher or the humidity exceeds 90%, for example, a warehouse without air conditioning equipment) for a long period of time such as one month or longer, The toner easily absorbs moisture or deteriorates due to heat, so that the chargeability and fluidity of the toner are likely to decrease.
If the toner stored for a long time in this high temperature and high humidity environment is used for a long time in the high temperature and high humidity environment, the developability of the toner may be deteriorated compared to the case where the stored toner without history is used. is there. This is because toner deterioration and moisture absorption have already progressed due to heat and humidity at the time of storage before use, and deterioration further proceeds in actual use.
Also, if the toner has deteriorated after a long period of use and there is a period of not being used for about one week, the toner charge has been significantly reduced, so the first few sheets when resuming use The image density tends to be thin. (Hereafter, sometimes referred to as low concentration after standing)

  Further, since the fluidity of the toner deteriorated in this manner is remarkably lowered, the waste toner in the cleaning container also deteriorates in fluidity, and remains in the vicinity of the cleaning blade and cannot move to the back. As a result, the waste toner scraped off by the cleaning blade is obstructed by the accumulated waste toner and does not enter the cleaning container, but easily passes through the cleaning blade and easily causes poor cleaning.

  Magnetic toner particles containing magnetic iron oxide have magnetic iron oxide exposed on the particle surface, and the exposed magnetic iron oxide has a large effect on the chargeability and fluidity of the magnetic toner. It is important to control the physical properties of magnetic iron oxide. Further, it is very important to control not only the physical properties of magnetic iron oxide but also the fluidity of magnetic toner.

  Also, cartridges stored for a long time in a high-temperature, high-humidity environment have the same temperature and humidity in the toner container, so if they are brought directly into a room with air conditioning equipment, moisture in the toner container may condense. is there. A toner agglomerate is generated using the condensed moisture as a nucleus, which may cause an image defect called white haze. The white haze is a phenomenon in which when a uniform density image pattern such as solid black or halftone is output, an area in which the toner is not developed in a circular shape with a size of about several mm to 10 mm is generated. There is a large relationship with the fluidity and chargeability of the.

As a result of investigations on these problems by the present inventors, it has been found that these problems can be solved by controlling the composition of magnetic iron oxide contained in the magnetic toner particles and the fluidity of the toner.
The toner in the cartridge that has been left for a long period of time has a large bulk density, and has almost lost its fluidity in a state of being closely packed in a container. The cartridge includes a member for agitating the toner, and the toner is agitated and has fluidity at the time of printing. It has been found that how the state changes from the state where there is almost no fluidity until it becomes fluidity greatly affects the developability and cleaning properties of the toner and the occurrence of white smear. Further, it has been found that the combination of the fluidity of the toner and the composition of the magnetic iron oxide also greatly affects the developability and cleaning properties of the toner and the occurrence of white fog.
In other words, by precisely controlling the fluidity of the toner and the composition of the magnetic iron oxide, even if the toner stored for a long time in a high temperature and high humidity environment is used for a long period of time, the developability is deteriorated, the cleaning is poor, It was found that the concentration was low and white haze could be suppressed.

That is, the magnetic toner of the present invention is a magnetic toner having toner particles containing at least a binder resin, wax, and magnetic iron oxide, and inorganic fine particles,
The magnetic iron oxide contains 0.30 mass% or more and 5.0 mass% or less of the Ti element with respect to the entire magnetic iron oxide,
The amount of Ti element (S-Ti) existing in the range where the Fe element dissolution rate is 10% or less is 40% or more and 70% or less of the total amount of Ti element contained in the magnetic iron oxide,
The amount of Ti element (M-Ti) existing in the range where the Fe element dissolution rate is greater than 10% and 50% or less is 10% or more and 40% or less of the total amount of Ti element contained in the magnetic iron oxide,
The amount of Ti element (C-Ti) existing in the range where the Fe element dissolution rate is greater than 50% and 100% or less is 1% or more and 20% or less of the total Ti element amount contained in the magnetic iron oxide,
(S-Ti), (M-Ti) and (C-Ti) satisfy the relationship of the following formulas (1) and (2),
Formula (1): (S—Ti) ≧ 2 × (C—Ti)
Formula (2): (M-Ti) ≧ 1.5 × (C—Ti)
[The dissolution rate of the Fe element is obtained by dissolving the magnetic iron oxide from the surface with an acid aqueous solution and setting the state in which the magnetic iron oxide is completely dissolved to 100% Fe element dissolution rate and dissolving the magnetic iron oxide in its entirety. The ratio of the amount of Fe element dissolved in the solution obtained in the process of dissolving the magnetic iron oxide from the surface with an acid aqueous solution to the total amount of Fe element when the amount of Fe element contained in the liquid is the total amount of Fe element (%). ]
The magnetic toner has a total torque E of rotational torque and vertical load in a non-ventilated state and a total sum Ea of rotational torque and vertical load in a vented state as measured by a powder flowability analyzer equipped with a rotary blade. The following expressions (3) and (4) are satisfied.
Formula (3): 600 (mJ) ≦ E ≦ 1500 (mJ)
Formula (4): 500 (mJ) ≦ (E-Ea)
[In the above formulas (3) and (4), E (mJ) is a powder fluidity analyzer equipped with a rotary blade, and the propeller type blade is the peripheral speed of the outermost edge of the propeller type blade is 100 mm. While rotating at / sec, the magnetic powder is filled into the toner powder layer in the measuring container filled with the magnetic toner, and the measurement is started from a position of 100 mm from the bottom surface of the toner powder layer. Represents the sum of rotational torque and vertical load obtained when approaching the position. In addition, Ea (mJ) is a rotational torque and a vertical load measured in a ventilation state in which a porous plate is arranged at the bottom of the measurement container and dry air having a flow rate of 0.20 mm / sec is sent therefrom. Represents the sum. ]

The magnetic iron oxide used in the present invention contains at least Ti element with respect to the entire magnetic iron oxide in a range of 0.30 mass% to 5.0 mass% (preferably 0.30 mass% to 3.0 mass%, More preferably 0.30 mass% or more and 2.0 mass% or less)
The amount of Ti element existing in the range where the Fe element dissolution rate is 10% or less (hereinafter also referred to as S-Ti) is 40% or more and 70% or less (preferably 50%) of the total amount of Ti element contained in the magnetic iron oxide. 70% or less)
The amount of Ti element existing in the range where the Fe element dissolution rate is greater than 10% and 50% or less (hereinafter also referred to as M-Ti) is 10% or more and 40% or less of all Ti elements contained in the magnetic iron oxide (preferably Is 20% or more and 40% or less),
The amount of Ti element existing in the range where the Fe element dissolution rate is greater than 50% and 100% or less (hereinafter also referred to as C-Ti) is 1% or more and 20% or less of the total Ti element contained in the magnetic iron oxide (preferably 1% to 10%)
The (S-Ti), (M-Ti), and (C-Ti) satisfy the following formulas (1) and (2).
Formula (1): (S—Ti) ≧ 2 × (C—Ti)
Formula (2): (M-Ti) ≧ 1.5 × (C—Ti)

  The above-mentioned magnetic iron oxide is dissolved from the surface with an acid aqueous solution, and the state in which all the magnetic iron oxide is dissolved is 100% Fe element dissolution rate, and the Fe element contained in the solution in which all the above-mentioned magnetic iron oxide is dissolved When the amount is the total Fe element amount, the ratio (%) of the Fe element amount dissolved in the solution obtained in the process of dissolving the magnetic iron oxide from the surface with the acid aqueous solution to the total Fe element amount is calculated according to the present invention. In this case, it is called the Fe element dissolution rate.

This indicates that the Ti element contained in the magnetic iron oxide is present from the vicinity of the center of the magnetic iron oxide to the surface, and more Ti element is distributed in the vicinity of the surface.
When the relationship of the above formulas (1) and (2) is satisfied, more Ti element exists on the surface of the magnetic iron oxide, and the adhesion between the binder resin and the magnetic iron oxide can be adjusted appropriately. As a result, it becomes easy to grind at the interface between the binder resin and the magnetic iron oxide in the grinding process at the time of toner production, and the magnetic iron oxide can be appropriately exposed on the surface of the magnetic toner particles.
The magnetic iron oxide exposed on the surface of the magnetic toner particles functions to improve the fluidity of the magnetic toner. Even if the magnetic toner is stored in a high-temperature and high-humidity environment for a long period of time, and the stored magnetic toner is used for a long period of time, the change in the fluidity of the magnetic toner can be reduced.
The reason for this is that the magnetic iron oxide exposed on the surface of the magnetic toner particles is in close contact with the binder resin, so even if the magnetic toner particles are subjected to thermal or mechanical stress during storage or long-term use, This is probably because magnetic iron oxide is difficult to be embedded in the magnetic toner particles.

  Since the magnetic iron oxide used in the present invention contains the Ti element, the charging property of the magnetic toner is also improved. In addition, by distributing the Ti element from the center to the surface of the magnetic iron oxide, the Ti element on the surface of the magnetic iron oxide can have a dense structure that is difficult to absorb moisture, even when stored in a high temperature and high humidity environment for a long time. In addition, the magnetic toner hardly absorbs moisture and the chargeability and fluidity are hardly deteriorated.

In addition, the Ti element on the surface of the magnetic iron oxide has a dense structure, the bond between Fe and Ti is strengthened, and even when mechanical stress is applied, the Ti element does not easily come off from the surface of the magnetic iron oxide. In addition, stable charging and fluidity can be imparted to the magnetic toner.
Furthermore, since more Ti element is present in the vicinity of the surface of the magnetic iron oxide, the rise of the charging of the magnetic toner is accelerated, so that even if the magnetic toner is left unused for a long period of time, it is sufficient from the first print. Image density can be obtained.

  The magnetic iron oxide used in the present invention is appropriately exposed on the surface of the magnetic toner particles and acts like a spacer, and has a function of making it difficult for the magnetic toner particles to come into contact with each other. Therefore, even if a cartridge stored for a long time in a high-temperature, high-humidity environment is brought into a room with air conditioning equipment and moisture in the toner container is condensed, toner agglomerates are less likely to be generated and the occurrence of white haze is suppressed. There is work.

The magnetic iron oxide used in the present invention contains at least Ti element with respect to the entire magnetic iron oxide in a range of 0.30 mass% to 5.0 mass% (preferably 0.30 mass% to 3.0 mass%, More preferably, it should be contained in an amount of 0.30% by mass to 2.0% by mass.
When the magnetic iron oxide contains the Ti element in this range, it becomes possible to impart appropriate fluidity and chargeability to the toner.
When the Ti element contained in the magnetic iron oxide is less than 0.30% by mass, it is difficult to obtain the effect of improving the fluidity and chargeability of the magnetic toner. If the Ti element contained in the magnetic iron oxide exceeds 5.0% by mass, the Ti element will be excessive with respect to the Fe element, making it difficult for the Ti element on the surface of the magnetic iron oxide to have a dense structure. It becomes easy to absorb moisture, the adhesiveness with the binder resin becomes too weak, free magnetic iron oxide increases, and fogging deteriorates.

  In the magnetic iron oxide used in the present invention, (S-Ti) needs to be 40% to 70% (preferably 50% to 70%) of the total amount of Ti element contained in the magnetic iron oxide. It is. The presence of Ti element at this ratio on the surface of magnetic iron oxide makes it easier for the magnetic iron oxide to be appropriately exposed on the surface of the magnetic toner particles, thereby suppressing toner deterioration. In addition, since the rising of the charging of the magnetic toner is accelerated, it is possible to suppress the low density after being left.

  When the above (S-Ti) is less than 40% of the total amount of Ti element contained in the magnetic iron oxide, the amount of Ti element present on the surface of the magnetic iron oxide is too small to prevent toner deterioration and density reduction after standing. It is difficult to obtain the effect. On the other hand, when (S-Ti) is more than 70% of the total amount of Ti element contained in the magnetic iron oxide, the magnetic iron oxide has a high hygroscopicity, and when left in a high-temperature and high-humidity environment for a long time, the magnetic toner It absorbs moisture and becomes difficult to be charged, and the concentration is likely to decrease. Further, the magnetic iron oxide exposed on the surface of the toner particles is easily detached from the surface of the toner particles, and the free magnetic iron oxide is increased to cause the fog to deteriorate.

  In the magnetic iron oxide used in the present invention, (M-Ti) needs to be 10% to 40% (preferably 20% to 40%) of the total amount of Ti element contained in the magnetic iron oxide. It is. When (M-Ti) is in this range, Ti and Fe can form a strong bond, and even when magnetic iron oxide is subjected to mechanical stress, it is difficult to deteriorate.

When the above (M-Ti) is less than 10% of the total amount of Ti element contained in the magnetic iron oxide, the amount of Ti element present in the magnetic iron oxide is small, and the Ti element increases rapidly in the vicinity of the magnetic iron oxide surface. Therefore, it is difficult to form a strong bond between Fe and Ti. As a result, the magnetic iron oxide exposed on the surface of the magnetic toner particles becomes weak against mechanical stress, and deterioration tends to proceed with long-term use.
On the other hand, if (M-Ti) is more than 40% of the total amount of Ti element contained in the magnetic iron oxide, the amount of Ti element that functions on the surface of the magnetic iron oxide is reduced. It is necessary to add more. On the other hand, unless the amount of Ti element added is increased, it is difficult to obtain a sufficient effect.

In the magnetic iron oxide used in the present invention, (C-Ti) needs to be 1% or more and 20% or less (preferably 1% or more and 10% or less) of the total amount of Ti element contained in the magnetic iron oxide. It is.
The above (C-Ti) is a factor that affects the surface properties of magnetic iron oxide. When (C-Ti) is in this range, the surface of magnetic iron oxide becomes smooth and the hygroscopicity of magnetic iron oxide. Therefore, a decrease in concentration due to long-term storage and a decrease in concentration after standing can be suppressed.
When the above (C-Ti) is less than 1% of the total amount of Ti element contained in the magnetic iron oxide, the Ti element increases rapidly in the vicinity of the magnetic iron oxide surface. The binding becomes weak, the dispersion of magnetic iron oxide in the magnetic toner particles deteriorates, and the amount of free magnetic iron oxide increases, or the hygroscopicity of magnetic iron oxide increases. The thin concentration deteriorates.
On the other hand, when (C—Ti) of the magnetic iron oxide used in the present invention is larger than 20% of the total amount of Ti element contained in the magnetic iron oxide, the crystallinity of the central portion of the magnetic iron oxide is lowered, and the magnetic oxidation Since the iron surface has many irregularities, it is difficult to obtain a sufficient effect of improving the chargeability and fluidity.

Furthermore, the present invention is characterized in that the above (S-Ti), (M-Ti), and (C-Ti) satisfy the relationship of the following formulas (1) and (2).
Formula (1): (S—Ti) ≧ 2 × (C—Ti)
Formula (2): (M-Ti) ≧ 1.5 × (C—Ti)
By satisfying the relations of the above formulas (1) and (2), it is possible to suppress the deterioration of the toner or to suppress the thinning of the density after leaving the magnetic toner to be charged quickly. Furthermore, the hygroscopicity of magnetic iron oxide can be reduced, and a decrease in concentration due to long-term storage and a decrease in concentration after standing can be suppressed.
When the above formula (1) is (S-Ti) <2 * (C-Ti) or the above formula (2) is (M-Ti) <1.5 * (C-Ti). In some cases, the Ti element distribution gradient in the magnetic iron oxide becomes small, and the Ti element functioning on the surface of the magnetic iron oxide decreases, so that a sufficient effect cannot be obtained. In addition, the mechanical strength of magnetic iron oxide may be insufficient, and may be easily deteriorated by long-term use, or a dense structure of Ti element may not be obtained and hygroscopicity may increase.

  The magnetic iron oxide used in the present invention preferably contains an Si element in addition to the Ti element. The content of Si element is 0.10% by mass or more and 4.0% by mass or less (more preferably 0.15% by mass or more and 3.5% by mass or less, further preferably 0.20%) with respect to the entire magnetic iron oxide. It is preferable that it is mass% or more and 3.0 mass% or less. By containing Si element in this range, it is preferable because the electric resistance of magnetic iron oxide can be increased and the chargeability of the toner can be increased.

  Furthermore, the magnetic iron oxide used in the present invention may contain a metal element other than Fe, Ti, and Si. In particular, the Al element is more preferably contained, and the content of the Al element is preferably 0.10% by mass or more and 3.0% by mass or less with respect to the entire magnetic iron oxide. The Al element is preferably present on the outermost surface of the magnetic iron oxide from the viewpoint of enhancing the dispersibility of the magnetic iron oxide in the magnetic toner particles.

  The magnetic iron oxide used in the present invention is composed of spherical particles in which the magnetic iron oxide particles are mainly formed with curved surfaces not having a plate-like surface, as observed by transmission electron micrographs. It is preferable not to contain it from the viewpoint of keeping the exposed state of magnetic iron oxide on the toner particle surface properly.

  In the magnetic toner of the present invention, the content of the magnetic iron oxide is preferably 20 to 200 parts by mass, more preferably 50 to 130 parts by mass with respect to 100 parts by mass of the binder resin. is there.

  The magnetic iron oxide used in the present invention has a number average particle size based on a measurement method described later of preferably 0.05 to 0.50 μm, more preferably 0.08 to 0.40 μm, and still more preferably. 0.10 to 0.30 μm. Setting the number average particle size in this range may be from the viewpoint of dispersibility of magnetic iron oxide in the binder resin constituting the toner particles and toner charging uniformity.

The magnetic iron oxide used in the present invention has a BET specific surface area of 15.0 m ² / g or less, preferably 13.0 m ² / g or less, based on the measurement method described later, so that the hygroscopicity of the magnetic iron oxide is reduced. It is preferable in that it can be suppressed.

As magnetic characteristics of the magnetic iron oxide used in the present invention, the saturation magnetization is preferably 10.0 to 200.0 Am ² / kg under a magnetic field of 795.8 kA / m, more preferably 60.
0~100.0Am a ² / kg, preferably residual magnetization is 1.0~100.0Am ² / kg, more preferably from 2.0~20.0Am ² / kg, a coercive force of 1 .0
It is preferable that it is 30.0 kA / m, More preferably, it is 2.0-15.0 kA / m. By having such magnetic characteristics, it is possible to obtain good developability in which the toner has a good balance between image density and fog.

The method for measuring various physical property data in the present invention is described in detail below.
(I) A method for quantifying the amount of Ti element existing in a range where the Fe element dissolution rate is 10% or less.
<1> Preparation of sample Weigh 25 g of magnetic iron oxide and place in a 5 L glass beaker. Next, while adding 5 L of 0.5 mol / L H ₂ SO ₄ and stirring, the temperature is gradually raised from room temperature to 80 ° C. in a water bath to gradually dissolve elements from the surface of magnetic iron oxide, Finally, all of the magnetic iron oxide is dissolved (note that the amount of Fe element contained in the solution in which all of the magnetic iron oxide is dissolved is defined as the total amount of Fe element). In the melting process of the magnetic iron oxide, 25 ml of the solution (slurry) is sampled when the magnetic iron oxide is dissolved to a state where 10% by mass of the Fe element is present in the solution. The collected slurry is filtered through a 0.1 μm membrane filter to obtain a filtrate.
<2> Measuring method The obtained filtrate is sprayed in inductively coupled plasma of an ICP emission photometric analyzer (trade name: ICPS2000, manufacturer: Shimadzu Corporation), and a wavelength of 334.94 nm (Ti) and a wavelength of 259.94 nm (Fe ) Is measured, and the Ti element concentration (mg / L) and Fe element concentration (mg / L) in the filtrate are quantified by comparing with the emission intensity of a calibration curve solution with a known concentration. . <3> Preparation method of the above-mentioned calibration curve solution 51 g of H ₂ SO ₄ is introduced into a 1000 mL polymeas flask, and the Fe element and Ti element have a concentration of [100 to 4000 mg / L] (Fe element), [0 Several levels of calibration curve solutions are prepared in a volume of 1000 mL with ion-exchanged water in addition to ˜30 mg / L] (Ti element).
<4> Calculation Formula The amount of Ti element (S-Ti) (mass%) and the amount of Fe element (mass%) existing in the range where the Fe element dissolution rate is 10% or less are calculated using the following equations.
(Formula): Fe element dissolution rate in the range of 10% or less Ti element amount (mass%), Fe element (mass%)
= (L × 5) / (S × 1000) × 100
L: concentration of each element obtained from ICP measurement value of each element (mg / L)
S: Sample weight 25 (g)
In addition, (M-Ti) and (C-Ti) are also quantified according to the above (S-Ti).

(II) Quantification method of total Si element amount (mass%), total Ti element (mass%), and total Al element (mass%) contained in magnetic iron oxide.
<1> Sample Preparation 1.00 g of magnetic iron oxide is weighed and placed in a 100 mL Teflon beaker. Next, 10 mL of water and 16 mL of concentrated hydrochloric acid are added and then heated to dissolve all the magnetic iron oxide. After cooling, 4 mL of hydrofluoric acid (1 + 1) is added and left for 20 minutes. Next, the obtained solution was transferred to a 100 mL polymer flask, and 1 mL of a surfactant (trade name: Triton X [10 g / L]) was added thereto.
Make up to 0 mL.
<2> Measuring method The sample solution prepared above is sprayed into inductively coupled plasma of an ICP emission photometric analyzer (trade name: ICPS2000, manufacturer: Shimadzu Corporation), and a wavelength of 288.16 nm (Si) and a wavelength of 396.15 nm ( Al), by measuring the emission intensity at a wavelength of 334.94 nm (Ti) and comparing it with the emission intensity of a calibration curve solution with a known concentration, Si element (mg / L) in the sample solution
, Ti element (mg / L) and Al element (mg / L) are quantified.
<3> Preparation method of the above calibration curve solution In a 1000 mL polymeas flask, 16 mL HCl, 4 mL HF (1 + 1), 1 m
L surfactant (1% Triton X) and 650 mg Fe were added, and Si element, Al element, and Ti element were added to a concentration of 0 to 200 mg / L, respectively, and 1000 mL with ion-exchanged water. Prepare several levels of standard solution with a constant volume.
<4> Calculation formula Total Si element content (mass%), Ti element content (mass%), and Al element content (mass%) contained in magnetic iron oxide are calculated using the following equations.
(Formula): Total amount of Si element contained in magnetic iron oxide (% by mass), amount of Ti element (% by mass), amount of Al element (% by mass)
= (L × 0.1) / (S × 1000) × 100
L: concentration of each element obtained from ICP measurement value of each element (mg / L)
S: Sample mass 1.0 (g)

(III) A method for measuring the number average particle diameter of magnetic iron oxide.
A photograph of magnetic iron oxide is taken at a magnification of 30000 using a transmission electron microscope. 100 magnetic iron oxide particles photographed in the photograph are randomly selected, the ferret diameter is measured, and the average value is taken as the number average particle diameter.

(IV) A method for measuring the specific surface area of magnetic iron oxide.
Using a specific surface area measuring device auto soap 1 (manufactured by Yuasa Ionics), nitrogen gas is adsorbed on the sample surface, and the specific surface area is calculated using the BET multipoint method.

(V) A method for measuring magnetic properties of magnetic iron oxide.
Using a vibrating sample magnetometer (VSM-3S-15, manufactured by Toei Kogyo Co., Ltd.), measurement is performed under an external magnetic field of 795.8 kA / m.

Although illustrated about the manufacturing method of magnetic iron oxide (for example, magnetite) used by this invention, it is not limited to the following manufacturing methods.
(First step)
An aqueous ferrous sulfate solution, sodium silicate, titanyl sulfate, sodium hydroxide and water are mixed to prepare a mixed solution. While maintaining the temperature of this mixed solution at 90 ° C. and maintaining the pH at 6 to 9, air is blown to wet-oxidize the ferrous hydroxide produced in the liquid. The formation of the central region of the magnetite particles produced when ferrous hydroxide is consumed 40 to 70% of the initial amount is confirmed.
(Second step)
During the first step, the progress rate of the oxidation reaction is examined by examining the concentration of unreacted ferrous hydroxide in the liquid, and the ferrous hydroxide is 40% of the initial amount. Identify when 70% is consumed. At the specified time, an aqueous ferrous sulfate solution having the same concentration as that used in the first step and titanyl sulfate are added to the solution, and water is further added to adjust the liquid volume. Sodium hydroxide is added to this to adjust the pH of the solution to 9-12. In this solution, the sodium silicate added in the first step remains. Air is blown at a liquid temperature of 90 ° C. to advance wet oxidation to generate an intermediate region.
(Third process)
During the second step, titanyl sulfate is added when the unreacted ferrous hydroxide in the liquid is consumed by 85 to 95% of the initial amount, and the reaction is further advanced. After confirming that almost 100% of the unreacted ferrous hydroxide in the liquid has been consumed, air blowing is stopped and aluminum sulfate is added to the liquid. Further, dilute sulfuric acid is added to adjust the pH of the solution to 5-9.
(Fourth process)
The magnetite particles thus obtained are washed and filtered by a conventional method, further dried and then pulverized to obtain the magnetic iron oxide used in the present invention.

In addition, the magnetic iron oxide used in the present invention is divided into four steps as described above, particularly the synthetic reaction production process, and the addition of Ti element while finely controlling the consumption of ferrous hydroxide in each step. By controlling the amount and timing of addition, the distribution of Ti element inside the magnetic iron oxide can be controlled, and the above characteristics can be imparted.

The magnetic toner of the present invention has a total E of rotational torque and vertical load in a non-ventilated state and a total Ea of rotational torque and vertical load in aerated state measured by a powder fluidity analyzer equipped with a rotary blade. Satisfies the following formulas (3) and (4).
Formula (3): 600 (mJ) ≦ E ≦ 1500 (mJ)
Formula (4): 500 (mJ) ≦ (E-Ea)
[In the above formulas (3) and (4), E (mJ) is a powder fluidity analyzer equipped with a rotary blade, and the propeller type blade is the peripheral speed of the outermost edge of the propeller type blade is 100 mm. While rotating at a speed of / sec, the magnetic powder is made to enter vertically into the toner powder layer in the measurement container filled with the magnetic toner, and measurement is started from a position 100 mm from the bottom surface of the toner powder layer. Represents the sum of rotational torque and vertical load obtained when approaching a position (ie, measurement in a non-vented state). In addition, Ea (mJ) is the sum of the rotational torque and the vertical load in a ventilation state in which a porous plate is disposed at the bottom of the measurement container and dry air with a flow rate of 0.20 mm / sec is sent therefrom in the above measurement. Represent. ]

In the present invention, the powder characteristic of the magnetic toner is a powder fluidity analyzer (powder rheometer FT-4, manufactured by Freeman Technology) equipped with a rotary blade (hereinafter abbreviated as FT-4). (Also available).
There are various conventionally known measuring methods for evaluating powder characteristics, and in particular, fluidity. For example, a powder tester (manufactured by Hosokawa Micron) can measure the angle of repose, the degree of compression, the spatula angle, the degree of uniformity, the degree of aggregation, and the like. However, these measurement results could not evaluate the fluidity of the powder in the static state and the dynamic state under the same conditions. For this reason, in some cases, sufficient knowledge cannot be obtained to evaluate the behavior of a toner in the case where the toner in a stationary state is given fluidity as in the present invention.

The FT-4 used for measuring the powder characteristics of the magnetic toner of the present invention can obtain information on rotational torque and vertical load applied to each of the toners in the states (i) to (iii) below.
(I) Toner when receiving force from outside in a stationary state.
(Ii) A toner in a state where fluidity is continuously maintained.
(Iii) A toner that changes from a state in which fluidity is maintained to a stationary state.
In particular, toner in a cartridge stored for a long time in a high-temperature and high-humidity environment has completely lost its fluidity, and therefore it is important to control the fluidity of the toner.

<Measurement method of E, Ea, Ed>
In the present invention, as described above, the measurement of E (mJ), Ea (mJ), and Ed (mJ) is performed using a powder fluidity analyzer (powder rheometer FT-4, Freeman Technology, Inc.) equipped with a rotary blade. Made).
The device moves a rotating blade in the powder sample to cause a constant flow measurement and pattern flow. The particles in the sample flow when the blade is in close proximity, and when they pass, they fall behind the blade and rest again. The energy required for the blade to move through the powder is calculated, and from this value the various fluidity indices are calculated. Since the blade is a propeller type and moves in the upward or downward direction at the same time as rotating, the tip draws a spiral. The angle and speed of the spiral path of the blade can be adjusted by changing the rotational speed and the vertical movement. When the blade moves along a clockwise spiral path with respect to the powder layer surface, there is an action of mixing the powder uniformly. Conversely, when the blade moves along a counterclockwise spiral path with respect to the powder layer surface, the blade receives resistance from the powder.
Specifically, the measurement is performed by the following operation. In all operations, the propeller type blade is a 48 mm diameter blade dedicated to FT-4 measurement (Fig. 1 There is a rotation axis in the normal direction at the center of the 48 mm x 10 mm blade plate. It is smoothly twisted counterclockwise such that the portion (24 mm from the rotating shaft) is 70 ° and the portion 12 mm from the rotating shaft is 35 °, and the material is made of SUS.Model number: C210. May be omitted).

First, a FT-4 measurement-only [50 mm × 160 ml] split container (model number: C203, 82 mm in height from the bottom of the container to the split part. The material is glass, hereinafter may be abbreviated as “container”). 1 magnetic toner left in a 95% humidity environment for 30 days
A toner powder layer is formed by adding 50 g.
Conditioning operation (a): Blade rotation speed (peripheral speed of the outermost edge of the blade) is 60 (mm / sec), vertical approach speed to the powder layer, the outermost edge of the moving blade is The angle formed between the locus to be drawn and the surface of the powder layer (hereinafter may be abbreviated as “the angle formed”) is 5 (deg) clockwise with respect to the surface of the powder layer (the powder is rotated by the rotation of the blade). The blade is advanced from the surface of the powder layer to the position of 10 mm from the bottom surface of the toner powder layer in the rotation direction (the direction in which the layers are uniformly mixed).
Thereafter, the blade rotation speed is 60 (mm / sec), the vertical approach speed to the powder layer is 2 (deg), and the rotation angle is clockwise with respect to the powder layer surface. Then, the blade is advanced from the bottom surface of the toner powder layer to a position of 1 mm.
Thereafter, the toner powder is rotated clockwise with respect to the surface of the powder layer at a rotation speed of the blade of 60 (mm / sec) and an angle forming the extraction speed from the powder layer of 5 (deg). The blade is moved to a position of 100 mm from the bottom of the layer and extracted.
When the extraction is completed, the toner attached to the blade is wiped off by rotating the blade alternately in small clockwise and counterclockwise directions.
(B): The series of operations (1) to (a) are performed five times in total to remove the air entrained in the toner powder layer, thereby forming a stable toner powder layer.

(2) Split operation A toner powder layer having the same volume is formed by scraping the toner powder layer at the split portion of the above-described cell dedicated to FT-4 measurement and removing the toner on the powder layer.

(3) Measurement operation (i): Measurement of E (mJ) (a): The same operation as (1)-(a) above is performed once.
(B): Next, the rotational speed of the blade is 100 (mm / sec), the vertical approach speed to the powder layer is an angle of 5 (deg), and counterclockwise with respect to the powder layer surface. The blade is caused to enter a position 10 mm from the bottom surface of the toner powder layer in a rotating direction (a direction in which resistance is received from the powder layer by rotation of the blade).
Thereafter, the blade rotation speed is 60 (mm / sec), the vertical approach speed to the powder layer is 2 (deg), and the rotation angle is clockwise with respect to the powder layer surface. Then, the blade is advanced from the bottom of the powder layer to a position of 1 mm.
Thereafter, the rotation speed of the blade is 60 (mm / sec), the angle forming the vertical extraction speed from the powder layer is 5 (deg), and in the clockwise rotation direction with respect to the powder layer surface, The blade is extracted from the bottom surface of the powder layer to a position of 100 mm.
When the extraction is completed, the toner attached to the blade is wiped off by rotating the blade alternately in small clockwise and counterclockwise directions.
(C): The series of operations in (b) above is performed a total of seven times.

In the above operation (c), it is obtained when the blade enters the position from 100 mm to 10 mm from the bottom surface of the toner powder layer when the rotation speed of the seventh blade is 100 (mm / sec). Let E (mJ) be the sum of rotational torque and vertical load.
E indicates the magnitude of the torque required to cause the toner to flow from the state where the toner does not have much fluidity, and the torque with which the toner is rubbed at the nip portion between the developing sleeve and the developing blade.

(Ii): Measurement of Ea (mJ) [50 mm × 200 ml] dedicated container for FT-4 measurement (model number: C200 and C620 (bottom plate for aeration). Height: 100 mm. Material is glass, hereinafter abbreviated as aeration container. The toner powder layer is formed by adding 150 g of magnetic toner left in an environment of temperature 40 ° C. and humidity 95% for 30 days.
(A): The toner powder for which the measurement of E (mJ) has been completed is put into an aeration container, and the above operations (1) to (a) are performed once.
(B): Next, dry air is gradually aerated from the porous plate at the bottom of the container so that the flow rate becomes 0.20 (mm / sec). At this time, a dedicated ventilation unit for FT-4 measurement is used.
(C) The above operations (i) to (b) are performed once in a state where dry air has become familiar to the toner.

(D): Toner powder in a state where dry air having a flow rate of 0.20 (mm / sec) is passed after the operation of (c) and the rotational speed of the blade is 100 (mm / sec). Let Ea (mJ) be the total of the rotational torque and the vertical load obtained when the blade enters from the bottom surface of the layer to a position of 100 mm to 10 mm.
Ea represents a torque applied when the toner is stirred when the toner has sufficient fluidity.

(Iii): Measurement of Ed (mJ) (a): After the operations of (ii)-(d), the supply of dry air is stopped, and at the same time, the operations of (i)-(b) are continued. The rotation obtained when the blade enters from the surface of the toner powder layer to the position of 10 mm from the bottom surface when the rotation speed of the blade at the fourth time is 100 (mm / sec). The sum of the torque and the vertical load is Ed (mJ).
Ed indicates the rate of change when a sufficiently fluid toner gradually loses fluidity.

It is important that the magnetic toner of the present invention satisfies 600 (mJ) ≦ E ≦ 1500 (mJ) [preferably 800 (mJ) ≦ E ≦ 1200 (mJ)]. This indicates that it is necessary to properly control the amount of torque applied when the toner is stationary, that is, when the toner is degassed and released from a dense state. Represents the initial toner state.
Since a certain amount of torque is required to loosen the densely packed magnetic toner, when the magnetic toner is developed, the magnetic toner is appropriately rubbed at the nip portion between the developing sleeve and the developing blade, and quickly charged. It becomes possible.
Even if toner aggregates are generated due to moisture condensation in the cartridge, the frictional force at the nip between the developing sleeve and the developing blade increases, so the aggregates are easily loosened, and the loosened magnetic toner is charged. Therefore, generation of white haze can be suppressed.
When 600 (mJ)> E, the torque required to loosen the densely packed magnetic toner is too small, and the toner easily slips through the nip between the developing sleeve and the developing blade, resulting in insufficient tribocharging and development. May decrease.
If 1500 (mJ) <E, the torque required to loosen the densely packed magnetic toner is too large, making it difficult to loosen sufficiently, and the magnetic toner does not loosen the nip between the developing sleeve and the developing blade. In some cases, the toner cannot pass through and cannot be sufficiently charged, resulting in a decrease in developability. Moreover, since the aggregate formed by dew condensation is hardly loosened, white haze is likely to occur.
In the present invention, E can be adjusted by controlling the content and distribution of Ti element in the magnetic iron oxide, the circularity of the magnetic toner particles, and the like.

The magnetic toner of the present invention is characterized in that 500 (mJ) ≦ (E−Ea) [preferably 700 (mJ) ≦ (E−Ea)]. This shows the difference between the torque applied when loosely packed toner is loosened and the torque applied when the toner is loosened and fluidity is restored. By increasing this difference, mechanical stress applied to the toner when the toner in the cartridge is agitated can be reduced, and deterioration of the toner can be prevented even during long-term use. With this effect, it is possible to suppress the occurrence of low density and poor cleaning due to deterioration.
In the case of 500 (mJ)> (E-Ea), the toner is likely to be deteriorated by long-term use, and the density is low and the cleaning failure is liable to occur.
In the present invention, Ea can be adjusted by controlling the content and distribution of Ti element in the magnetic iron oxide, the circularity of the magnetic toner particles, the adhesion state of the external additive, and the like.

In the magnetic toner of the present invention, the sum Ed of the rotational torque and the vertical load after the change from the aeration state to the non-aeration state, measured by a powder flowability analyzer equipped with a rotary blade, It is preferable to satisfy (5).
Formula (5): 0.10 <(Ed / E) <0.70 [preferably 0.30 ≦ (Ed / E) ≦ 0.60]
[In the above formula (5), Ed (mJ) is a flow of 0.20 (mm / sec) dry air into the powder phase of the magnetic toner in the container, and the ventilation is stopped after measuring Ea. Then, the same measurement as E (mJ) was repeated four times, and the blade from the surface of the toner powder layer to the position of 10 mm from the bottom surface when the rotation speed of the fourth blade was 100 (mm / sec). Represents the sum of the rotational torque and the vertical load obtained when the is entered. ]

The above (Ed / E) indicates the ease of maintaining the fluidity of the toner and represents the ease of stirring in the toner container of the cartridge, that is, the ease of toner circulation.
The toner is circulated by being agitated in the toner container, and the toner around the developing sleeve is appropriately replaced, so that deterioration of the toner can be suppressed, and good developability and cleaning properties can be maintained over a long period. . Further, since the toner circulates in the container, not only the toner around the developing sleeve but also the entire toner in the container can be charged, fogging can be suppressed, and good developability can be obtained.
In the present invention, it is possible to adjust Ed by controlling the content and distribution state of Ti element in magnetic iron oxide, the particle size distribution and circularity of magnetic toner particles, the adhesion state of external additives, and the like. .

The magnetic toner of the present invention has a circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) of 0.20.
It is preferable that the average circularity analyzed by dividing into 800 in the circularity range of 0 to 1.000 is 0.940 or more (preferably 0.950 or more and 1.000 or less). By increasing the average circularity, the magnetic iron oxide exposed on the surface works effectively, and the effect of improving the fluidity and chargeability of the toner is enhanced. When the average circularity is 0.940 or more, the number of concave portions on the surface of the magnetic toner particles is reduced, so that the magnetic iron oxide exposed on the surface of the magnetic toner particles is likely to be involved in chargeability and fluidity. It becomes easy to obtain the effect. In other words, toner deterioration is suppressed even during long-term use after long-term storage, and thinning of the density and poor cleaning are less likely to occur.

<Measuring method of average circularity>
The average circularity of the magnetic toner is measured using a flow type particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.
A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop ultrasonic cleaner disperser (for example, “VS-150” (manufactured by Velvo Crea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.
For the measurement, the flow type particle image measuring apparatus equipped with a standard objective lens (10 times) is used, and a particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image measuring apparatus, and 3000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the equivalent circle diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the magnetic toner is obtained.
In the measurement, before starting the measurement, standard latex particles (for example, Duke Science)
Automatic focusing is performed using “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by tific. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.
In the present invention, a flow type particle image measuring apparatus that has been calibrated by Sysmex Corporation and that has been issued a calibration certificate issued by Sysmex Corporation is used. Measurement is performed under the measurement and analysis conditions when the calibration certificate is received, except that the analysis particle diameter is limited to a circle equivalent diameter of 1.985 μm or more and less than 39.69 μm.
The measurement principle of the flow-type particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation) is to take a flowing particle as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is captured by a CCD camera, and the captured image is subjected to image processing at an image processing resolution of 512 × 512 (0.37 × 0.37 μm per pixel), and the contour of each particle image is extracted, The projected area S, the peripheral length L, and the like are measured.
Next, the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity C is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. And is calculated by the following formula.
Circularity C = 2 × (π × S) ^1/2 / L
When the particle image is circular, the circularity is 1.000. The greater the degree of irregularities on the outer periphery of the particle image, the smaller the circularity. After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.

The magnetic toner of the present invention preferably contains 0.01 parts by mass or more and 1.00 parts by mass or less of a hydrotalcite compound with respect to 100 parts by mass of the toner particles.
Hydrotalcite compounds have the effect of increasing the chargeability of the toner, and are particularly effective in situations where the toner is difficult to be charged, such as after being left in a high temperature and high humidity environment for a long period of time.
As the hydrotalcite compound, hydrotalcite represented by the following general formula is preferably added.

M1 to Mj in the above general formula of hydrotalcite are divalent metal ions different from each other, specifically, from the group consisting of Mg, Zn, Ca, Ba, Ni, Sr, Cu and Fe as appropriate. You can choose. Among these, Mg is preferable, and it is preferable that the content (molar fraction) of metal ions other than Mg satisfies the relationship of 0.001 ≦ y2 +... + Yj ≦ 0.05.
Further, L1 to Lk in the above general formula are trivalent metal ions different from each other, and specifically, can be appropriately selected from the group consisting of Al, B, Ga, Fe, Co, and In. Among these, Al is preferable, and it is preferable that the content (molar fraction) of metal ions other than Al satisfies the relationship of 0.0003 ≦ x2 +... + Xk ≦ 0.02.
Furthermore, it is preferable that two or more kinds of the above divalent metal ions and trivalent metal ions exist.

As A (n-valent anion) of the above general formula, CO ₃ ²⁻ , OH ⁻ , Cl ⁻ , I ⁻ , F ⁻ , Br ⁻ , SO ₄ ²⁻ , HCO ³⁻ , CH ₃ COO ⁻ , NO ₃ ^-, salicylate ^-, citrate ^3, tartrate ^{2-, (OOC-COO) 2-} , [Fe (CN) 6] 4- is exemplified, they exist at least one or It doesn't matter.
Further, in the above general formula, m ≧ 0, but from the viewpoint of stabilization of charging property, it is preferable to have crystal water in the molecule in advance, and 0.1 <m <0.6. It is more preferable.

Examples of the hydrotalcite compound include Mg _0.75 Al _0.25 (OH) ₂ (CO ₃ ) _0.125 · 0.5H ₂ O, Mg _0.69 Al _0.31 (OH) ₂ (CO ₃ ) _0.15 · 0.54H ₂ O, Mg _0.72 Al _0.28 (OH) ₂ (CO ₃ ) _0.14 · 0.54H ₂ O.

Hydrotalcite compound used in the present invention, BET specific surface area of 1.0 m ² / g or more, more preferably a 5.0~100m ² / g, and an average primary particle size of 1μm or less Is preferred.
The hydrotalcite compound used in the present invention may be hydrophobized with a surface treatment agent. As the surface treatment agent, oils such as higher fatty acids, coupling agents, esters and silicone oil can be used. Among these, higher fatty acids are preferably used, and specific examples include stearic acid, oleic acid, lauric acid and the like.
As the surface treatment method of the hydrotalcite compound with the surface treatment agent as described above, a conventionally known method can be used. For example, a method of dissolving and mixing the surface treatment agent in a solvent, heating and dissolving into a liquid state And a wet mixing method with an untreated hydrotalcite compound, and a mechanical dry mixing method of the particulate surface treatment agent and the hydrotalcite compound. After the surface treatment, if necessary, for example, means such as washing, dehydration, drying, pulverization, and classification can be appropriately selected and applied to obtain a hydrotalcite compound subjected to the surface treatment.
The amount of the hydrotalcite compound added to the toner particles is preferably 0.01 parts by weight or more and 1.00 parts by weight or less, more preferably 0.05 parts by weight or more, based on 100 parts by weight of the toner particles. .50 parts by mass or less.

  Examples of the binder resin contained in the toner particles used in the present invention include vinyl resins, polyester resins, epoxy resins, polyurethane resins and the like, but are not particularly limited, and conventionally known resins can be used. Among these, from the viewpoint of achieving both chargeability and fixability, it is preferable to contain a polyester resin or a vinyl resin. In particular, use of a resin having a polyester unit is advantageous because fixability is advantageous.

The composition of the polyester resin is as follows.
Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-
Butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexane Diol, hydrogenated bisphenol A, bisphenol represented by the following formula (A) and derivatives thereof; diols represented by the following formula (B).

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙ平均値は０〜１０である。）

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)

（ｘ’及びｙ’は、０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）

(X ′ and y ′ are integers of 0 or more, and the average value of x + y is 0 to 10.)

  Divalent acid components include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or their anhydrides, lower alkyl esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid. Or its anhydride, lower alkyl ester; alkenyl succinic acid or alkyl succinic acid such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or anhydride, lower alkyl ester thereof; fumaric acid, maleic acid, citraconic acid, itaconic acid, etc. Dicarboxylic acids such as unsaturated dicarboxylic acids or anhydrides thereof, lower alkyl esters; and derivatives thereof.

  In the present invention, a carboxylic acid component containing 90 mol% or more of an aromatic carboxylic acid compound and a polyester obtained by condensation polymerization of an alcohol component, and 80 mol% or more of the aromatic carboxylic acid compound is terephthalic acid and / or isophthalic acid. Although it is not clear why the acid is used, it is preferable in terms of enhancing the uniform dispersibility of the internal additive such as magnetic iron oxide and wax.

  In addition, the use of trivalent or higher alcohol components and trivalent or higher acid components acting as crosslinking components alone or in combination achieves more uniform dispersibility of internal additives such as magnetic iron oxide and wax. This is preferable.

  Examples of the trihydric or higher polyhydric alcohol component include 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, etc. Can be mentioned.

Trivalent or higher polyvalent carboxylic acid components include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylene Carboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, and anhydrides thereof, lower alkyl esters; tetracarboxylic acid represented by the following formula (C) and the like, and anhydrides thereof And polyvalent carboxylic acids such as lower alkyl esters and derivatives thereof.

（式中Ｘは炭素数３以上の側鎖を１個以上有する炭素数５〜３０のアルキレン基又はアルケニレン基）

(Wherein X is an alkylene group or alkenylene group having 5 to 30 carbon atoms having one or more side chains having 3 or more carbon atoms)

  The alcohol component is 40 to 60 mol%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol%, preferably 55 to 45 mol%.

  The polyester resin is usually obtained by commonly known condensation polymerization.

On the other hand, the following are mentioned as a vinyl-type monomer for producing | generating a vinyl-type resin.
Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene derivatives such as styrene, pn-butyl styrene, p-tert butyl styrene, pn hexyl styrene, pn octyl styrene, pn nonyl styrene, pn decyl styrene, pn dodecyl styrene; Unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate and propionic acid Vinyl esters such as vinyl and vinyl benzoate; Methyl acrylate, ethyl methacrylate, propyl methacrylate, nbutyl methacrylate, isobutyl methacrylate, n octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, methacryl Α-methylene aliphatic monocarboxylic esters such as diethylaminoethyl acid; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-acrylic acid 2- Acrylic acid esters such as ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl Vinyl ethers such as ethers; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; Vinyl Naphthalenes; and acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

In addition, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Unsaturated dibasic acid half esters such as alkenyl succinic acid methyl half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester; dimethyl maleic acid, unsaturated dibasic acid ester such as dimethyl fumaric acid; acrylic acid, Α, β-unsaturated acids such as phosphoric acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic anhydride and cinnamic anhydride, the α, β-unsaturated acids and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Furthermore, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

In the magnetic toner of the present invention, the vinyl resin of the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups.
Examples of the crosslinking agent used in this case include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate and 1,3-butylene glycol diene. Acrylate, 1,4-butanediol diacrylate, 1,5-pentanediol acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylate of the above compounds with methacrylate Examples of diacrylate compounds linked by an alkyl chain containing an ether bond include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyethylene glycol # 4. 00 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and the above compounds in which acrylate is replaced with methacrylate; chained with a chain containing an aromatic group and a steric bond Examples of diacrylate compounds include polyoxyethylene (2) -2,2-bis (4hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4hydroxyphenyl) propane Examples include diacrylate and those obtained by replacing acrylate of the above compound with methacrylate; examples of polyester-type diacrylate compounds include trade name MANDA (Nippon Kayaku).

  In addition, as polyfunctional cross-linking agents, pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds are replaced with methacrylate. Triallyl cyanurate, triallyl trimellitate;

These crosslinking agents are preferably used in an amount of 0.01 to 10 parts by mass (more preferably 0.03 to 5 parts by mass) with respect to 100 parts by mass of other monomer components.
Among these crosslinking agents, aromatic divinyl compounds (particularly divinylbenzene), diacrylate compounds linked by a chain containing an aromatic group and an ether bond are preferably used from the standpoint of fixability and offset resistance. Is mentioned.

Examples of the polymerization initiator used for producing the vinyl copolymer include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethyl). Valeronitrile), 2,2′-azobis (-2,4-dimethylvaleronitrile), 2,2′-azopis (-2methylptyronitrile), dimethyl-2,2′-azobisisoptylate, 1 , 1′-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl -4-methoxyvaleronitrile, 2,2-azobis (2-methylpropane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide Ketone peroxides such as oxide, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di -T-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, denoyl peroxide, Lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propiyl Peroxydicarbonate, di-2-engineered tooxyethyl peroxycarbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxy Acetate, t-butyl peroxyisoptylate, t-butyl peroxyneodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxybenzoate, t-butylperoxyisopropyl carbonate, di-t-butylperoxyisophthalate, t-butylperoxyallyl carbonate, t-amylperoxy 2-ethylhexanoate, di-t-butylperoxyhexahydroterephate Examples include tarate and di-t-butyl peroxyazelate.

The binder resin has a glass transition temperature (Tg) of 45 to 70 ° C., preferably 50 to 70 ° C., more preferably 52 to 65 ° C., from the viewpoint of easy compatibility between low temperature fixability and storage stability. There should be.
When the glass transition temperature (Tg) is lower than 45 ° C., the storage stability of the toner tends to be lowered. On the other hand, when the glass transition temperature (Tg) is higher than 70 ° C., the low-temperature fixability tends to decrease. The glass transition temperature (Tg) is measured according to ASTM D3418-82 using, for example, a differential scanning calorimetric analyzer “Q1000” (manufactured by TA Instruments).

The binder resin preferably has an acid value of 1 to 100 mgKOH / g, more preferably 10.0 to 60.0 mgKOH / g, from the viewpoint of charging stability of the magnetic toner. More preferably, it is 15.0 to 40.0 mgKOH / g.
The acid value is the number of mg of potassium hydroxide necessary to neutralize the acid contained in 1 g of the sample. The acid value is measured according to JIS K 0070-1992.

  The toner particles used in the present invention contain a wax. As the wax, hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax are preferably used because of easy dispersion in toner particles and high releasability. Depending on the type, one or two or more kinds of waxes may be used in small amounts. Examples of the wax used in combination include the following.

Oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax, sazol wax, and montanate wax; and deoxidation The fatty acid esters such as carnauba wax may be partially or wholly deoxidized. Furthermore, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as pracidic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, and seryl alcohol Saturated alcohols such as melyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylene bis stearic acid amide, ethylene biscaprin Saturated fatty acid bisamides such as acid amide, ethylene bislauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl Unsaturated fatty acid amides such as dipinamide, N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylenebisstearic acid amide, N, N-distearylisophthalic acid amide; calcium stearate, laur Grafted with fatty acid metal salts such as calcium phosphate, zinc stearate, magnesium stearate (generally called metal soap), and aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid. Examples of waxes include partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols, and methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils and the like.

  The melting point defined by the peak temperature of the maximum endothermic peak at the time of temperature rise measured with a differential scanning calorimeter (DSC) of the wax is preferably 70 to 140 ° C., more preferably 90 to 135. ° C. When the melting point is lower than 70 ° C., the toner tends to deteriorate, and when the melting point exceeds 140 ° C., the low-temperature fixability tends to decrease.

The peak temperature of the maximum endothermic peak of the wax (hereinafter also referred to as the melting point) is measured according to ASTM D3418-82 using a differential scanning calorimeter “Q1000” (TA Instruments).
The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium.
Specifically, about 10 mg of wax is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference. Measurement is performed at ° C / min. In the measurement, the temperature is once raised to 200 ° C., subsequently lowered to 30 ° C., and then the temperature is raised again. The maximum endothermic peak of the DSC curve in the temperature range of 30 to 200 ° C. in the second temperature raising process is defined as the maximum endothermic peak of the endothermic curve in the DSC measurement. And the peak temperature of this maximum endothermic peak is calculated | required.

The amount of the wax added is preferably 0.1 to 20 parts by mass and more preferably 0.5 to 10 parts by mass per 100 parts by mass of the binder resin.
Also, these waxes can be added by dissolving the resin in a solvent during binder resin production, increasing the resin solution temperature, and adding and mixing the wax while stirring, or adding the wax during melt kneading during toner particle production. It can be contained in the binder resin by a method to be used.

  The magnetic toner of the present invention preferably contains a charge control agent. The following substances are used as charge control agents for controlling the toner to be negatively charged.

  For example, organometallic compounds and chelate compounds are effective, and there are monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid-based metal compounds. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol.

  Specifically, an azo metal compound represented by the following structural formula (1) is preferable.

〔式中、Ｍは中心金属を示し、具体的にはＳｃ、Ｔｉ、Ｖ、Ｃｒ、Ｃｏ、Ｎｉ、ＭｎまたはＦｅ等があげられる。Ａｒはアリーレン基を示し、フェニレン基、ナフチレン基などがあげられ、置換基を有してもよく、置換基としては、ニトロ基、ハロゲン基、カルボキシル基、アニリド基および炭素数１〜１８のアルキル基、アルコキシ基などがある。Ｘ、Ｘ’、Ｙ及びＹ’はそれぞれ独立して−Ｏ−、−ＣＯ−、−ＮＨ−、−ＮＲ−（Ｒは炭素数１〜４のアルキル基）である。Ａ＋はカウンターイオンを示し、具体的には水素イオン、ナトリウムイオン、カリウムイオン、アンモニウムイオンあるいは脂肪族アンモニウムイオンを示す。〕

[In the formula, M represents a central metal, and specific examples include Sc, Ti, V, Cr, Co, Ni, Mn, and Fe. Ar represents an arylene group, such as a phenylene group and a naphthylene group, and may have a substituent. Examples of the substituent include a nitro group, a halogen group, a carboxyl group, an anilide group, and an alkyl group having 1 to 18 carbon atoms. Groups, alkoxy groups and the like. X, X ′, Y, and Y ′ are each independently —O—, —CO—, —NH—, —NR— (R is an alkyl group having 1 to 4 carbon atoms). A + represents a counter ion, and specifically represents a hydrogen ion, a sodium ion, a potassium ion, an ammonium ion, or an aliphatic ammonium ion. ]

  In particular, Fe or Cr is preferable as the central metal in the structural formula (1). Moreover, as a substituent substituted by the arylene group in the said Structural formula (1), a halogen atom, an alkyl group, or an anilide group is preferable. The counter ion in the structural formula (1) is preferably a hydrogen ion, an alkali metal ammonium ion, or an aliphatic ammonium ion. A mixture of compounds having different counter ions is also preferably used.

  Alternatively, a basic organic acid metal compound represented by the following structural formula (2) also gives negative chargeability and can be used in the present invention.

In particular, the central metal in the structural formula (2) is preferably Fe, Cr, Si, Zn, Zr or Al. Moreover, as a substituent substituted by the arylene group in said Structural formula (2), an alkyl group, an anilide group, an aryl group, and a halogen atom are preferable. The counter ion in the structural formula (2) is preferably a hydrogen ion, an ammonium ion, or an aliphatic ammonium ion.
Among these, the azo metal compound represented by the structural formula (1) is more preferable, and the azo iron compound represented by the following structural formula (3) is most preferable.

  Next, specific examples of the above compounds are shown.

Examples of the charge control agent for controlling the toner to be positively charged include the following substances.
Modified products with nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, onium salts such as phosphonium salts and lake pigments thereof, tri Phenylmethane dyes and their lake pigments (including phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid,
Gallic acid, ferricyanide, ferrocyanide); metal salts of higher fatty acids; guanidine compounds, imidazole compounds. These can be used alone or in combination of two or more. Among these, triphenylmethane compounds and quaternary ammonium salts whose counter ions are not halogen are preferably used.

  Further, a homopolymer of a monomer represented by the following structural formula (4); a copolymer of this and a polymerizable monomer such as styrene, acrylic acid ester or methacrylic acid ester can be used as a positive charge control agent. . In this case, these charge control agents also have an action as a binder resin (all or a part thereof).

〔式中、Ｒ₁はＨ又はＣＨ₃を示し、Ｒ₂及びＲ₃は置換または未置換のアルキル基（好ましくは、Ｃ１〜Ｃ４）を示す〕

[Wherein R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably C1 to C4)]

  Furthermore, as a specific example of the charge control agent, a compound represented by the following structural formula (5) can be preferably exemplified.

〔式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５及びＲ_６は、各々互いに同一でも異なっていてもよい水素原子、置換もしくは未置換のアルキル基または、置換もしくは未置換のアリール基を表し、Ｒ_７、Ｒ_８及びＲ_９は、各々互いに同一でも異なっていてもよい水素原子、ハロゲン原子、アルキル基、アルコキシ基を表し、Ａ⁻は、硫酸イオン、硝酸イオン、ほう酸イオン、りん酸イオン、水酸イオン、有機硫酸イオン、有機スルホン酸イオン、有機りん酸イオン、カルボン酸イオン、有機ほう酸イオン又はテトラフルオロボレートから選択される陰イオンを示す。〕

[Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each a hydrogen atom which may be the same as or different from each other, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl. R ₇ , R ₈ and R ₉ each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, which may be the same or different from each other, and A ⁻ represents a sulfate ion, a nitrate ion, a borate ion, An anion selected from phosphate ion, hydroxide ion, organic sulfate ion, organic sulfonate ion, organic phosphate ion, carboxylate ion, organic borate ion or tetrafluoroborate. ]

Preferred specific examples (commodities) of the negatively chargeable charge control agent include the following.
Spiron Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, S-54, E-84, E-88, E-89 ( Orient Chemical Industry Co., Ltd.).
Preferred specific examples (commodities) of positively chargeable charge control agents include the following.
TP-302, TP-415 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) N-01, N-04, N-07, P-51 (Orient Chemical Co., Ltd.), Copy Blue PR ( Clariant).

  As a method for adding the charge control agent to the toner, there are a method of adding the toner inside the toner particles and a method of adding the toner externally. The amount of these charge control agents to be used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and a dispersion method, and is not uniquely limited. The amount is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin.

  In the magnetic toner of the present invention, inorganic fine particles are externally added to the toner particles in order to improve the fluidity of the toner. As the inorganic fine particles, fluorine resin fine particles such as vinylidene fluoride fine particles and polytetrafluoroethylene fine particles; fine particle silica such as wet method silica and dry method silica, fine particle titanium oxide, fine particle alumina, organosilicon compound, titanium coupling these Examples thereof include treated silica, treated titanium oxide, and treated alumina that have been surface treated (hydrophobized) with an agent, silicone oil, and the like.

Among the above, preferable inorganic fine particles are fine particles generated by vapor phase oxidation of a silicon halogen compound, and are referred to as dry process silica or fumed silica. For example, it utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.
SiCl ₄ + 2H ₂ +0 ₂ → SiO ₂ + 4HCl
In this production process, it is possible to obtain composite fine particles of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride or titanium chloride together with silicon halogen compounds. As the particle size, the number average particle size of the primary particle size is preferably in the range of 0.001 to 2 μm, and particularly preferably in the range of 0.002 to 0.2 μm.

  Furthermore, the silica fine particles produced by vapor phase oxidation of the silicon halogen compound are more preferably treated silica fine particles having a hydrophobic surface. The treated silica fine particles are particularly preferably those obtained by treating the silica fine particles so that the degree of hydrophobicity measured by a methanol titration test is in the range of 30-80.

  Examples of the hydrophobic treatment method include a method of chemically treating with an organosilicon compound and / or silicone oil that reacts or physically adsorbs with silica fine particles. A preferred method is a method of chemically treating silica fine particles produced by vapor phase oxidation of a silicon halogen compound with an organosilicon compound.

Examples of the organosilicon compound include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, and bromomethyl. Dimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, Diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divirtetramethyldisiloxane, 1,3 -Diphenyltetramethyldisiloxane and dimethylpolysiloxane having 2 to 12 siloxane units per molecule and one hydroxyl group on the terminal unit Si. These are used alone or in a mixture of two or more.

  In addition, aminopropyltrimethoxysilane having nitrogen atom, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyl Trimethoxysilano, dioctylaminopropyldimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ-propylbenzylamine Such silane coupling agents may be used alone or in combination. A preferred silane coupling agent is hexamethyldisilazane (HMDS).

The silicone oil preferably has a viscosity at 25 ° C. of 0.5 to 10000 mm ² / S, more preferably 1 to 1000 mm ² / S, and still more preferably 10 to 200 mm ² / S. Specific examples include dimethyl silicone oil, methyl fell silicone oil, α-methyl styrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil.
As a method for treating the silicone oil, for example, a method in which silica fine particles treated with a silane coupling agent and silicone oil are directly mixed using a mixer such as a Henschel mixer; Or a method in which silicone oil is dissolved or dispersed in a suitable solvent, and then silica fine particles are added and mixed to remove the solvent.
More preferably, the silica treated with silicone oil is heated to 200 ° C. or higher (more preferably 250 ° C. or higher) in an inert gas after the treatment of silicone oil to stabilize the surface coat.
In the present invention, the silica is preferably treated by a method in which silica is treated with a coupling agent and then treated with silicone oil, or a method in which silica is treated with a coupling agent and silicone oil at the same time.

The inorganic fine particles preferably have a specific surface area by nitrogen adsorption measured by the BET method of 30 m ² / g or more, and more preferably 50 m ² / g or more.
The amount of the inorganic fine particles added is preferably 0.01 to 8 parts by mass, more preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the toner particles.
The specific surface area by nitrogen adsorption measured by the BET method is measured according to JIS Z8830 (2001). As a measuring device, an “automatic specific surface area / pore distribution measuring device TriStar 3000 (manufactured by Shimadzu Corporation)” which employs a gas adsorption method by a constant volume method as a measuring method is used.

  The average circularity of the magnetic toner of the present invention is determined by adjusting the toner manufacturing method and manufacturing conditions. Such a method for producing the magnetic toner of the present invention is exemplified below.

The magnetic toner of the present invention preferably has a step of adjusting the degree of circularity, but the other manufacturing steps are not particularly limited and can be manufactured by a known method.
For example, the manufacturing method is as follows. First, a binder resin, wax and magnetic iron oxide, and, if necessary, other materials such as a colorant and a charge control agent are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, The resins are mixed with each other by melting, kneading and kneading using a heat kneader such as a kneader or an extruder. The obtained melt-kneaded product is cooled and solidified, and then roughly pulverized using a pulverizer, and then preferably obtained through a surface modification step and mixing external additives such as inorganic fine particles with the mixer. it can. If necessary, a classification process using a classifier may be further performed either before or after the surface modification process.

  As the above mixer, Henschel mixer (made by Mitsui Mining Co., Ltd.); Super mixer (made by Kawata Co., Ltd.); Ribocorn (made by Okawara Seisakusho Co., Ltd.); (Manufactured by Taiheiyo Kiko Co., Ltd.);

  Examples of the kneader include KRC kneader (manufactured by Kurimoto Iron Works); Bus co-kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Nippon Steel) PCM kneading machine (Ikegai Iron Works); Three roll mill, mixing roll mill, kneader (Inoue Seisakusho); Needex (Mitsui Mining); MS pressure kneader, Nider Ruder (Moriyama Seisakusho) A Banbury mixer (manufactured by Kobe Steel).

  Examples of the pulverizer include counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Co.); IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Industry Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); (Manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (manufactured by Seishin Enterprise Co., Ltd.); kryptron (manufactured by Kawasaki Heavy Industries Ltd.); turbo mill (manufactured by Turbo Kogyo Co., Ltd.); super rotor (Nisshin Engineering).

The classifiers include: Classy, Micron Classifier, Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Classifier (Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Co., Ltd.) ); Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Industrial Co., Ltd.); YM Microcut (manufactured by Yaskawa Shoji Co., Ltd.) and the like.
As a sieving device used for sieving coarse particles, Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (manufactured by Deoksugaku Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Corp.); Soniclean (new) Examples include a turbo screener (manufactured by Turbo Industry Co., Ltd.), a micro shifter (manufactured by Kanno Sangyo Co., Ltd.), and a circular vibrating sieve.

Next, a batch-type surface modification apparatus that is preferably used in the surface modification step in the above manufacturing method will be described.
The batch type surface reforming apparatus shown in FIG. 2 includes a cylindrical main body casing 30, a top plate 43 installed on the upper portion of the main body casing so as to be openable and closable; It has a cooling jacket 31 through which cooling water or antifreeze can be passed.

  Further, the batch type surface reforming apparatus shown in FIG. 2 has a plurality of dispersing hammers 33 which are square disks on the upper surface, which are attached to the central rotating shaft in the main body casing 30 as surface modifying means. A distributed rotor 32 that is a disk-shaped rotating body that rotates at a high speed in a predetermined direction; a plurality of grooves are provided on the surface facing the distributed rotor 32 that are fixedly arranged around the distributed rotor 32 at a constant interval. The liner 34 is provided.

  Further, the batch type surface modification apparatus shown in FIG. 2 includes a classification rotor 35 for continuously removing fine powder having a predetermined particle size or less in the powder particles; a cold air introduction port for introducing cold air into the main body casing 30. 46: An inlet pipe having a raw material inlet 37 and a raw material inlet 39 formed on the side surface of the main casing 30 for introducing powder particles (raw material).

Further, the batch type surface modification apparatus shown in FIG. 2 is a product discharge pipe having a product discharge port 40 and a product extraction port 42 for discharging the toner particles after the surface modification treatment to the outside of the main body casing 30; Can be freely adjusted, and an openable and closable raw material supply valve 38 installed between the raw material input port 37 and the raw material supply port 39; and a product installed between the product discharge port 40 and the product extraction port 42 A discharge valve 41 is provided.
Further, the product discharge pipe is sucked by the blower 365 in order to suck and discharge the toner particles after the surface modification treatment.

Further, the batch type surface reforming apparatus shown in FIG. 2 has a guide ring 36 as a cylindrical guide means having an axis perpendicular to the top plate 43 in the main body casing 30. The upper end of the guide ring 36 is usually provided at a predetermined distance from the top plate (usually about 20 to 50 mm), and at least a part of the classification rotor 36 is installed in a state where it is covered with the cylinder. .
Further, the lower end of the guide ring 36 is provided at a predetermined distance from the dispersion hammer 33 which is a disk portion of the dispersion rotor 32 or a square disk. By this guide ring 36, the space between the classification rotor 35 and the dispersion rotor 32-liner 34 in the apparatus is divided into a first space 47 outside the guide ring and a second space 48 inside the guide ring. .
Here, the first space 47 is a space for introducing the powder particles into the classification rotor 35, and the second space is a space for introducing the powder particles into the dispersion rotor.
A gap between the dispersion hammer 33, which is a square disk installed on the dispersion rotor 32, and the liner 34 is the surface modification zone 49, and the classification rotor 35 and the peripheral portion of the rotor are the classification zone 50. .

In the batch-type surface reforming apparatus configured as described above, with the product discharge valve 41 closed, the raw material supply valve 38 is opened, and the surface modified particles are charged from the raw material charging port 37. After a certain period of time, the raw material supply valve 38 is closed.
The powder particles introduced into the apparatus from the raw material supply port 39 are first sucked by the blower 364 and classified by the classification rotor 35. At that time, the classified fine powder having a predetermined particle size or less is continuously discharged and removed out of the apparatus through the fine powder discharge portion 44 and the fine powder discharge port 45.
The blower 364 and the blower 365 may be the same blower or may be separate blowers.

Powder particles having a predetermined particle diameter or more are guided along the inner circumference (second space 48) of the guide ring 36 by centrifugal force, and are circulated along the circulating flow generated by the dispersion rotor 32 to the surface modification zone 49. . In generating the circulating flow, the peripheral speed of the dispersion rotor is preferably 30 m / sec to 200 m / sec, and more preferably 70 m / sec to 170 m / sec. In general, the degree of surface modification tends to increase as the peripheral speed of the dispersion rotor increases.
The powder particles guided to the surface modification zone 49 are subjected to a mechanical impact force between the dispersion hammer 33, which is a square disk installed on the dispersion rotor 32, and the liner 34. Quality.

  The surface-modified powder particles are guided to the classification zone 50 while swirling along the outer periphery (first space 47) of the guide ring 36 along the cold air and blower suction flow passing through the machine. By the rotor 35, the fine powder is again discharged to the outside of the machine through the fine powder discharge portion 44 and the fine powder discharge port 45, and the coarse powder is returned to the surface modification zone 49 again through the circulation flow, and repeatedly performs the surface modification action. receive.

After a predetermined time has elapsed, the product discharge valve 41 is opened, and at the same time, the surface modified particles are sucked and discharged from the product extraction port 42 by the blower 365. Here, the processing time is defined as the time from when the raw material particles are charged into the apparatus until the product discharge valve is opened. The longer the treatment time, the lower the production capacity, but the higher the surface modification degree.
By sucking and discharging, most of the surface modified particles in the apparatus are discharged out of the apparatus in a short time, so that the particles staying in the apparatus are reduced and the difference in the degree of surface modification between the particles is reduced. As a result, the toner charge amount distribution becomes sharp and developability can be improved.

The weight average particle diameter (D4) of the magnetic toner of the present invention is calculated as follows.
As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.
As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.
Prior to measurement and analysis, the dedicated software is set as follows.
On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.
In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.
The specific measurement method is as follows.
(1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4).

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In addition, the number of parts in the following composition is part by mass unless otherwise specified.
(Production example 1 of magnetic iron oxide)
[Step 1]
Mixing 5 L of ferrous sulfate aqueous solution containing 1.8 mol / L of Fe ²⁺ , 15 g of sodium silicate with 13.4% Si grade, 2.5 g of titanyl sulfate with 20.0% Ti grade, and 650 g of sodium hydroxide Then, water was added to make the total volume 10 L. While maintaining the temperature of this solution at 90 ° C. and maintaining the pH at 6-9, air was blown at 2 L / min to wet-oxidize the ferrous hydroxide produced in the liquid. When 90% of the ferrous hydroxide was consumed with respect to the initial amount, formation of a portion serving as a core of magnetite was confirmed. This core part contained Ti.
[Step 2]
During the course of step 1, the progress of the oxidation reaction is examined by examining the concentration of unreacted ferrous hydroxide in the solution. Ferrous hydroxide is consumed by 90% of the initial amount. At that time, 4 L of an aqueous ferrous sulfate solution having the same concentration as that used in Step 1, 15 g of Si grade 13.4% sodium silicate, and 12 g of titanyl sulfate grade 20.0% were added to the solution. In addition, water was added to make the liquid volume 18L. In addition, sodium hydroxide was added to adjust the pH of the solution to 9-12. In this solution, sodium silicate and titanyl sulfate added in Step 1 remained. Air was blown at a liquid temperature of 90 ° C. at 1 L / min to advance wet oxidation, and an intermediate layer made of magnetite containing Ti was generated.
[Step 3]
During the process 2, the progress rate of the oxidation reaction is examined by examining the concentration of unreacted ferrous hydroxide in the liquid. When 90% of the ferrous hydroxide is consumed, the Si quality is reached. 13 g of 13.4% sodium silicate and 26.5 g of titanyl sulfate having a Ti grade of 20.0% were added to the liquid. In addition, sodium hydroxide was added to adjust the pH of the solution to 9-12. In this solution, sodium silicate and titanyl sulfate added in steps 1 and 2 remained. Air was blown at a liquid temperature of 90 ° C. at 1 L / min to advance wet oxidation, and magnetite containing Si and Ti was generated.
[Step 4]
After confirming that 100% of the unreacted ferrous hydroxide in the liquid was consumed in step 3, air blowing was stopped and 65.5 g of aluminum sulfate having an Al grade of 6% was added to the liquid. did. Further, dilute sulfuric acid was added to adjust the pH of the solution to 5 to 9, and Al was deposited on the magnetite surface.
The magnetite particles thus obtained were washed and filtered by a conventional method, further dried and pulverized to obtain magnetic iron oxide 1. Various characteristics of the obtained magnetic iron oxide 1 were measured. The results are shown in Table 1.

(Production Examples 2 to 5 of Magnetic Iron Oxide, Production Examples 1 and 2 of Comparative Magnetic Iron Oxide)
In magnetic iron oxide production example 1, the amounts of titanyl sulfate, sodium silicate, and aluminum sulfate were appropriately changed, and the addition timing was finely adjusted. Iron oxides 1 and 2 were obtained. Table 1 shows the measurement results of the various characteristics.

(Example of binder resin production)
-18 parts by mass of terephthalic acid-3 parts by mass of isophthalic acid-7 parts by mass of trimellitic anhydride-Bisphenol derivative represented by the above formula (A) (R: propylene group x + y = 2.2)
70 parts by mass of 5.6 mol EO adduct of novolak type phenolic resin (number of nuclei of about 5.6)
2 parts by mass 0.5 parts by mass of tetrabutyl titanate as a catalyst was added to these and subjected to condensation polymerization at 240 ° C. to form a crosslinked polyester resin (Tg = 59 ° C., main peak molecular weight = 7,500, tetrahydrofuran insoluble matter = 14 masses). %). This was used as a binder resin for the magnetic toner of the present invention.

Example 1
-100 parts by mass of the polyester resin-100 parts by mass of magnetic iron oxide 1 (number average particle size 0.18 µm)-3 parts by mass of polyethylene wax (melting point = 101 ° C, Mn = 850)

-2 parts by mass of the azo-based iron compound (1) (the counter ion is NH ₄ ⁺ )

The raw materials were premixed with a Henschel mixer, and then kneaded by a twin-screw kneading extruder (PCM-30: manufactured by Ikegai Iron Works Co., Ltd.) set at a temperature of 120 ° C. and a rotation speed of 200 rpm. The obtained melt-kneaded product was cooled, and the cooled melt-kneaded product was coarsely pulverized with a cutter mill. Using the turbo mill T-250 (manufactured by Turbo Kogyo Co., Ltd.), the resulting coarsely pulverized product is finely pulverized by adjusting the air temperature so that the exhaust temperature is 48 ° C., and a multi-division classifier utilizing the Coanda effect And classified.
This classified product was put into the surface modification apparatus shown in FIG. 2 equipped with a dispersion rotor having a diameter of 300 mm and subjected to surface modification treatment. At this time, the peripheral speed of the dispersion rotor was 120 m / sec, and the processing time was set to 25 seconds. Moreover, the air volume of the classification part at the time of discharging | emitting the surface-modified particle | grains from a product discharge part was 3.0 m < ³ > / min, and the air volume of the product discharge part was 1.5 m < ³ > / min. The magnetic toner particles obtained by surface modification in this manner are referred to as magnetic toner particles 1.
100 parts by mass of the magnetic toner particles 1, 1.2 parts by mass of hydrophobic silica fine particles obtained by subjecting dry silica (BET: 200 m ² / g) to hexamethyldisilazane treatment and then dimethyl silicone oil treatment, hydrotal 0.10 parts by mass of a site compound [Mg _0.72 Al _0.28 (OH) ₂ (CO ₃ ) _0.14 · 0.54H ₂ O; BET specific surface area 10 m ^{2 /} g], strontium titanate (number Magnetic toner 1 was prepared by charging 1.0 part by mass of an average particle size of 0.50 μm into a Henschel mixer (FM-10B; manufactured by Mitsui Mining Co., Ltd.) and mixing at 3,500 rpm for 2 minutes. Table 2 shows the physical properties of this magnetic toner 1.

(Example 2)
A magnetic toner 2 was prepared in the same manner as in Example 1 except that no hydrotalcite compound was added. Table 2 shows the physical properties of this magnetic toner 2.

(Example 3)
A magnetic toner 3 was prepared in the same manner as in Example 2 except that the surface modification treatment by the surface modification apparatus was not performed. Table 2 shows the physical properties of this magnetic toner 3.

Example 4
Magnetic toner 4 was prepared in the same manner as in Example 3 except that the mixing condition by the Henschel mixer was changed to 2,500 rpm for 2 minutes. Table 2 shows the physical properties of this magnetic toner 4.

(Example 5)
Magnetic iron oxide 2 is used instead of magnetic iron oxide 1, and the coarsely pulverized product is finely pulverized using a jet mill (IDS-2 type; manufactured by Nippon Pneumatic Industry Co., Ltd.) instead of using Turbo Mill T-250. Magnetic toner 5 was prepared in the same manner as in Example 4 except that the amount of hydrophobic silica fine particles added was changed to 1.5 parts by mass. Table 2 shows the physical properties of this magnetic toner 4.

(Example 6)
A magnetic toner 6 was prepared in the same manner as in Example 5 except that magnetic iron oxide 3 was used instead of magnetic iron oxide 2. The physical properties of this magnetic toner 6 are shown in Table 2.

(Example 7)
A magnetic toner 7 was prepared in the same manner as in Example 5 except that magnetic iron oxide 4 was used instead of magnetic iron oxide 2. The physical properties of this magnetic toner 7 are shown in Table 2.

(Example 8)
Magnetic toner 8 was prepared in the same manner as in Example 5 except that magnetic iron oxide 5 was used instead of magnetic iron oxide 2. The physical properties of this magnetic toner 8 are shown in Table 2.

(Comparative Example 1)
Comparative magnetic toner 1 was prepared in the same manner as in Example 5 except that comparative magnetic iron oxide 1 was used instead of magnetic iron oxide 2. Table 2 shows the physical properties of this comparative magnetic toner 1.

(Comparative Example 2)
Comparative magnetic toner 2 was prepared in the same manner as in Example 5 except that comparative magnetic iron oxide 2 was used instead of magnetic iron oxide 2. Table 2 shows the physical properties of this comparative magnetic toner 2.

(Comparative Example 3)
Comparative magnetic toner 3 was prepared in the same manner as in Example 8, except that 1.0 part by mass of titanium oxide (number average particle size 0.1 μm) was used instead of strontium titanate. Table 2 shows the physical properties of the comparative magnetic toner 3.

(Evaluation of magnetic toner)
These magnetic toners 1 to 8 and comparative magnetic toners 1 to 3 were evaluated as follows.
(1) Evaluation of white haze A cartridge for a commercially available LBP printer (Laser Jet 4350, manufactured by hp) was filled with 1,000 g of magnetic toner, and a temperature of 40 ° C. was used as an acceleration test for long-term storage in a high temperature and high humidity environment. And left in an environment of 95% humidity for 30 days. After leaving for 30 days, remove the cartridge and seal it in a plastic bag. Immediately before the temperature cools down, move the cartridge to an environment with a temperature of 15 ° C and a humidity of 10%. confirmed.
For the image output, a commercially available LBP printer (Laser Jet 4350, manufactured by hp) was remodeled to make A4 size 60 sheets / min (process speed 370 mm / sec).
A solid black image was printed on the entire surface of the evaluation paper, and the level of white haze was evaluated based on the number of occurrences of white haze per sheet and the number of sheets passed until disappearance. It was judged that there was no problem in practical use up to rank C, and that there was a possibility of occurrence in actual use in rank D.
(Evaluation criteria)
A: No occurrence B: One white haze occurs per sheet, but disappears when no more than 5 sheets pass.
C: 2 to 5 white haze occurs per sheet, but disappears when 10 sheets or less pass.
D: 6 to 10 white haze occurs per sheet, but disappears when 30 sheets or less pass.
E: 11 or more white haze occurs per sheet and does not disappear even when 30 sheets are passed.

  In addition, in order to confirm the influence of dew condensation in the toner container of the cartridge, the cartridge after being left in a high temperature and high humidity environment for 30 days is moved in the same way to an environment of 32.5 ° C. and 80% humidity to remove white moisture. As a result, no white fog was generated with any of the toners. From this result, it was confirmed that this evaluation was able to monitor the change in image quality due to changes in the usage environment.

(2) Evaluation of developability and cleaning property In the same manner as the white haze evaluation, the cartridge was filled with 1,000 g of magnetic toner, and as an accelerated test for long-term storage in a high temperature and high humidity environment, the temperature was 40 ° C and the humidity was 95%. For 30 days. After leaving for 30 days, the cartridge was taken out, moved to an environment with a temperature of 32.5 ° C. and a humidity of 80%, and left overnight to let the cartridge adapt to the environment, and then the development durability of the toner was evaluated.
Using the modified machine used in the white haze evaluation, the horizontal line pattern with a printing rate of 1% was set to 1 sheet / job, and the machine was temporarily stopped between jobs and the next job started. A print test of 30,000 sheets was performed in the mode. The durability of the toner was evaluated by the image density and fogging after the initial printing test and after printing 30,000 sheets.
Furthermore, the cartridge after printing 30,000 sheets is left as it is for 1 week in an environment with a temperature of 32.5 ° C. and a humidity of 80%. The occurrence was confirmed.
Further, regarding the cleaning property, the horizontal line image printed out in the evaluation of the development durability was visually confirmed, and the evaluation was made at the level of occurrence of defective cleaning (a belt-like black streak occurs in the vertical direction of the image).
(Evaluation criteria for cleaning properties)
A: Not generated B: Generated but disappeared when 3 sheets or less passed.
C: Generated but disappeared when no more than 5 sheets were passed.
D: Disappeared with 10 sheets or less, but reoccurs 2-3 times during durability evaluation.
E: Does not disappear after occurrence.

The image density was measured by measuring the reflection density of a solid black image with a Macbeth densitometer (manufactured by Macbeth) using an SPI filter.
As for fog, a solid white image was measured on a transfer material before and after image formation using a reflection densitometer (reflectometer model TC-6DS manufactured by Tokyo Denshoku Co., Ltd.). The worst reflection density after image formation was Ds, the reflection average density of the transfer material before image formation was Dr, and Ds-Dr was determined and evaluated as the fog amount. A smaller number indicates that fogging is suppressed.
These evaluation results are shown in Table 3.

It is explanatory drawing of a 48 mm diameter propeller type blade only for FT-4 measurement. It is a schematic diagram of a batch type surface modification apparatus.

Explanation of symbols

30 Main body casing 31 Cooling jacket 32 Dispersion rotor 33 Dispersion hammer 34 Liner 35 Classification rotor 36 Guide ring 37 Raw material inlet 38 Raw material supply valve 39 Raw material supply port 40 Product discharge port 41 Product discharge valve 42 Product extraction port 43 Top plate 44 Fine powder discharge Portion 45 Fine powder outlet 46 Cold air inlet 47 First space 48 Second space 49 Surface modification zone 50 Classification zone 364 Blower 365 Blower T1 Thermometer T2 Thermometer

Claims (4)

A magnetic toner having toner particles containing at least a binder resin, wax, and magnetic iron oxide, and inorganic fine particles,
The magnetic iron oxide contains 0.30 mass% or more and 5.0 mass% or less of the Ti element with respect to the entire magnetic iron oxide,
The amount of Ti element (S-Ti) existing in a range where the Fe element dissolution rate is 10% or less is 40% or more and 70% or less of the total amount of Ti element contained in the magnetic iron oxide,
The amount of Ti element (M-Ti) existing in the range where the Fe element dissolution rate is greater than 10% and 50% or less is 10% or more and 40% or less of the total amount of Ti element contained in the magnetic iron oxide,
The amount of Ti element (C-Ti) existing in the range where the Fe element dissolution rate is greater than 50% and 100% or less is 1% or more and 20% or less of the total Ti element amount contained in the magnetic iron oxide,
(S-Ti), (M-Ti) and (C-Ti) satisfy the relationship of the following formulas (1) and (2),
Formula (1): (S—Ti) ≧ 2 × (C—Ti)
Formula (2): (M-Ti) ≧ 1.5 × (C—Ti)
[The dissolution rate of the Fe element is obtained by dissolving the magnetic iron oxide from the surface with an acid aqueous solution and setting the state in which the magnetic iron oxide is completely dissolved to 100% Fe element dissolution rate and dissolving the magnetic iron oxide in its entirety. The ratio of the amount of Fe element dissolved in the solution obtained in the process of dissolving the magnetic iron oxide from the surface with an acid aqueous solution to the total amount of Fe element when the amount of Fe element contained in the liquid is the total amount of Fe element (%). ]
The magnetic toner has a total torque E of rotational torque and vertical load in a non-ventilated state and a total sum Ea of rotational torque and vertical load in a vented state as measured by a powder flowability analyzer equipped with a rotary blade. A magnetic toner satisfying the following formulas (3) and (4):
Formula (3): 600 (mJ) ≦ E ≦ 1500 (mJ)
Formula (4): 500 (mJ) ≦ (E-Ea)
[In the above formulas (3) and (4), E (mJ) is a powder fluidity analyzer equipped with a rotary blade, and the propeller type blade is the peripheral speed of the outermost edge of the propeller type blade is 100 mm. While rotating at / sec, the magnetic powder is filled into the toner powder layer in the measuring container filled with the magnetic toner, and the measurement is started from a position of 100 mm from the bottom surface of the toner powder layer. Represents the sum of rotational torque and vertical load obtained when approaching the position. In addition, Ea (mJ) is a rotational torque and a vertical load measured in a ventilation state in which a porous plate is arranged at the bottom of the measurement container and dry air having a flow rate of 0.20 mm / sec is sent therefrom. Represents the sum. ] For the magnetic toner, the sum Ed of the rotational torque and the vertical load after the change from the aerated state to the non-aerated state, measured by a powder flowability analyzer equipped with a rotary blade, 2) The magnetic toner according to claim 1, wherein:
Formula (5): 0.10 <(Ed / E) <0.70
[In the above formula (5), Ed (mJ) is a flow of 0.20 (mm / sec) dry air into the powder phase of the magnetic toner in the container, and the ventilation is stopped after measuring Ea. Then, the same measurement as E (mJ) was repeated four times, and the blade from the surface of the toner powder layer to the position of 10 mm from the bottom surface when the rotation speed of the fourth blade was 100 (mm / sec). Represents the sum of the rotational torque and the vertical load obtained when the is entered. ] The magnetic toner has a circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) in a circularity range of 0.200 to 1.000. 3. The magnetic toner according to claim 1, wherein the average circularity analyzed by dividing into 800 parts is 0.940 or more.   The magnetic toner contains a hydrotalcite compound in an amount of 0.01 parts by mass to 1.00 parts by mass with respect to 100 parts by mass of toner particles. The magnetic toner described in 1.

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