JP4590193B2 - toner - Google Patents

Description

  The present invention relates to a toner used for electrophotography, an image forming method for developing an electrostatic image, and a toner used for a toner jet.

In recent years, devices using electrophotography have begun to be used in printers for output of computers, facsimiles, etc., in addition to copying machines for copying original documents. As a result, smaller, lighter, faster, and more reliable are being sought, and machines are becoming simpler in various ways. As a result, the performance required for the toner becomes higher, and if the improvement in the performance of the toner cannot be achieved, a better machine cannot be realized.

  Patent Documents 1 to 4 disclose techniques for bringing the shape of a toner closer to a sphere by a manufacturing method such as a spray granulation method, a solution dissolution method, or a polymerization method. However, both of these techniques require large-scale equipment for toner production, which is not preferable in terms of production efficiency and has not yet sufficiently reduced toner consumption.

  Patent Documents 5 to 7 disclose techniques for adding to a toner base for the purpose of imparting fluidity or controlling chargeability. However, even if the properties of the toner are improved by these methods, the developability is still not sufficient, and since all of them are attached to the toner base, the magnetic material is likely to be liberated, causing various harmful effects. was there.

Japanese Patent Laid-Open No. 3-84558 JP-A-3-229268 Japanese Patent Laid-Open No. 4-1766 JP-A-4-102862 JP-A-2-269362 JP-A-3-67268 JP-A-7-230182

  An object of the present invention is to provide a toner that solves the above-mentioned problems of the prior art.

  An object of the present invention is to provide a toner that consumes less toner per image and can achieve a long life with a small amount of toner.

  An object of the present invention is to provide a toner having excellent developability in any environment.

  An object of the present invention is to provide a toner that does not generate blotch and tailing.

  An object of the present invention is to provide a toner that does not generate image flow, drum fusion, and white streaks.

The present invention is a magnetic one-component toner having toner particles containing at least a binder resin and a magnetic material,
The magnetic material contains 0.3 to 0.9% by mass of Si element based on the magnetic material, and is further selected from the group consisting of Mn, Zn, Cu, and Al as metal elements other than iron The total amount of the other metal elements is 0.4 to 1.2% by mass based on the magnetic material,
The magnetic one-component toner of the flow type particle image analyzer average circularity of the circle equivalent diameter 400μm or less of the magnetic one-component toner or 3μm measured by is less than 0.930 or 0.970,
The magnetic one-component toner 40mg dispersed in an aqueous surfactant solution 5ml, yet 6mol / l extraction solution surface magnetic of the magnetic one-component toner adding hydrochloric acid 5ml of 30 minutes, the absorption 340nm derived from a magnetic substance The surface absorbance is 2.55 to 3.10 and is surface-modified by a surface modification device that performs surface modification and fine powder removal.
The surface treatment apparatus includes a dispersion rotor for performing a surface modification treatment using a mechanical impact force, a liner disposed with a predetermined gap around the outer periphery of the dispersion rotor, and a surface-modified raw material. Having at least a classification rotor for classifying to a predetermined particle size,
In the number-based particle size distribution of toner particles having an equivalent circle diameter of 0.6 μm or more and 400 μm or less measured by the flow type particle image measuring apparatus of the toner particles, the ratio of toner particles of 0.6 μm or more and less than 3 μm is 0% by number or more The present invention relates to a magnetic one-component toner characterized by being less than 20% by number.

  Low toner consumption per image, long life can be achieved with a small amount of toner, and excellent developability is maintained in any environment, blotching, tailing, image flow, drum fusion In addition, a toner that does not generate white streaks can be provided.

  As a result of intensive studies, the present inventors have found that the developing characteristics of the toner can be controlled by controlling the circularity of the toner and controlling the amount of magnetic material on the toner surface.

  The toner of the present invention has an average circularity of 0.930 or more and less than 0.970, preferably 0.935 or more and less than 0.965, more preferably 0.935 or more and less than 0.960, in a toner having a particle diameter of 3 μm or more. Preferably, the amount of toner consumed per image area can be reduced by 0.940 or more and less than 0.955. As the circularity of the toner increases, the fluidity of the toner increases, so that the individual toners can move freely. The toner developed on a transfer material such as paper has a higher probability of being developed in units of toner as the toner has a higher degree of circularity, so the image height on the transfer material is lower and the toner consumption is reduced. The amount can be reduced. At this time, if the degree of circularity of the toner is not sufficiently high, the toner tends to behave as an aggregate and is easily developed on the transfer material as an aggregate. In such an image, the height of the image from the transfer material becomes high, and when the same area is developed, more toner is developed than toner having excellent fluidity, and the amount of toner consumption increases. In addition, toner with a high degree of circularity tends to be denser in the developed image. As a result, the toner concealment ratio with respect to the transfer material is increased, and a sufficient image density can be obtained even with a small amount of toner. If the average circularity is less than 0.930, the height of the developed image becomes high and the toner consumption increases. In addition, since voids between toners increase and a sufficient concealment rate cannot be obtained even in a developed image, a larger amount of toner is required to obtain a required image density, resulting in toner consumption. Will increase. Further, toner scattering is likely to occur, and dot reproducibility also deteriorates. When the average circularity is 0.970 or more, the toner is coated on the sleeve non-uniformly due to excessive supply of toner on the developing sleeve, resulting in blotch.

The average circularity in the present invention is used as a simple method for quantitatively expressing the particle shape. In the present invention, the flow type particle image analyzer FPIA-2100 manufactured by Sysmex Corporation is used at 23 ° C. and 60%. Measurement is performed under the environment of RH, and particles within a circle equivalent diameter of 0.60 μm to 400 μm are measured. The circularity of the measured particle is obtained by the following equation (1), and further, the circle equivalent diameter is 3 μm to 400 μm. In the following particles, the value obtained by dividing the total circularity by the total number of particles is defined as the average circularity.
Circularity a = L ₀ / L (1)
[In the formula, L ₀ represents the perimeter of a circle having the same projection area as the particle image, and L represents the particle projection when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm). Indicates the perimeter of the image. ]

  The circularity used in the present invention is an index of the degree of unevenness of the toner, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated. In addition, “FPIA-2100”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle, and then calculates the average circularity by calculating the circularity of each particle. A calculation method is used in which 1.0 is divided into 61 classes and the average circularity is calculated using the center value and frequency of the division points. However, the error of the average circularity calculated by the calculation formula using the average circularity value calculated by this calculation method and the total circularity of each particle is very small and can be substantially ignored. In the present invention, for the reason of handling data such as shortening the calculation time and simplifying the calculation operation formula, the concept of the calculation formula using the sum of the circularity of each particle is used and partly changed. Such a calculation method may be used. Furthermore, the measurement device used in the present invention, “FPIA-2100”, has a thinner sheath flow (7 μm → 4 μm) than “FPIA1000” which has been used to calculate the shape of the toner. ) And the magnification of the processed particle image, and further the processing resolution of the captured image (256 × 256 → 512 × 512), the accuracy of toner shape measurement has been improved, thereby making sure the fine particles are more reliable. A device that has achieved capture. Therefore, when it is necessary to measure the shape and particle size distribution more accurately as in the present invention, the FPIA 2100 that can obtain information on the shape and particle size distribution more accurately is more useful.

As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersing agent to 200 to 300 ml of water from which impurities in the container have been removed in advance, and a measurement sample is 0. Add about 1-0.5g. The suspension in which the sample is dispersed is dispersed with an ultrasonic oscillator for 2 minutes, and the circularity distribution of the particles is measured at a dispersion concentration of 0.2 to 1 million particles / μl. As the ultrasonic oscillator, for example, the following apparatus is used, and the following dispersion conditions are used.
UH-150 (manufactured by SMT Corporation)
OUTPUT level: 5
Constant mode

  The outline of the measurement is as follows.

  The sample dispersion is passed through a flow path (expanded along the flow direction) of a flat and flat flow cell (thickness: about 200 μm). The strobe and the CCD camera are mounted on the flow cell so as to be opposite to each other so as to form an optical path that passes through the thickness of the flow cell. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. Photographed as a two-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. The circularity of each particle is calculated from the projected area of the two-dimensional image of each particle and the perimeter of the projected image using the above circularity calculation formula.

  In the present invention, the toner particle ratio of 0.6 to 3 μm is zero in the number-based particle size distribution of toner particles having an equivalent circle diameter of 0.6 to 400 μm measured by a flow type particle image measuring device. % Or more and less than 20%, preferably 0% or more and less than 17%, more preferably 1% or more and less than 15%. The toner particles used for the measurement herein refer to the base material before the inorganic fine powder or hydrophobic inorganic fine powder is externally added. Hereinafter, the ultrafine powder of 0.6 μm or more and less than 3 μm refers to the toner base (toner particles) before external addition. Toner particles having a size of 0.6 μm or more and less than 3 μm have a great influence on the developability of the toner, particularly the fog characteristics. Such a fine particle toner has an excessively high chargeability, is easily developed excessively at the time of developing the toner, and appears as fog on the image. However, in the present invention, the fog can be reduced by the small proportion of the fine particle toner.

  Next, conditions for kneading the toner constituent materials using a thermal kneader will be described as a preferred method for obtaining the toner characteristic of the present invention. The kneading conditions include kneading temperature and screw shaft rotation speed.

  In the present invention, by setting the kneading temperature and the screw shaft rotation speed to appropriate values, the dispersion of the magnetic material in the toner kneaded product can be improved, and an appropriate amount of magnetic material on the toner surface after the surface modification treatment Can be formed.

  The kneading temperature is preferably 70 to 180 ° C. The molten toner temperature is preferably 100 to 200 ° C. When the set temperature is less than 70 ° C., the dispersion of the magnetic material is deteriorated and the molecular resistance of the binder resin is further cut, so that the offset resistance is deteriorated. When the set temperature is higher than 180 ° C., the dispersion of the wax is extremely deteriorated.

  The screw shaft rotation speed is preferably 110 to 160 rpm. When the screw shaft rotational speed is less than 110 rpm, the dispersion of the magnetic material is deteriorated. When the screw shaft rotation speed is larger than 160 rpm, the offset resistance deteriorates because the molecular chains of the binder resin are cut.

  As a kneading machine, 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 Works); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); kneedex (manufactured by Mitsui Mining Co., Ltd.); Banbury mixer (manufactured by Kobe Steel) can be mentioned.

  Next, a toner particle manufacturing method using a surface modification step will be described as a preferred method for obtaining toner particles characterized by the present invention. Hereinafter, a surface modifying device used in the surface modifying step and a toner particle manufacturing method using the surface modifying device will be specifically described with reference to the drawings.

  FIG. 1 shows an example of a surface modification apparatus used in the present invention, and FIG. 2 shows an example of a top view of a rotor that rotates at a high speed in FIG.

  In the surface modification apparatus shown in FIG. 1, a casing, a jacket (not shown) through which cooling water or antifreeze liquid can be passed, and a surface modification means, which is in the casing and attached to the central rotating shaft, has a square shape on the upper surface. A plurality of discs or cylindrical pins 40, and a distributed rotor 36 which is a rotating body on a disk rotating at high speed, and a plurality of grooves on the surface arranged at regular intervals on the outer periphery of the distributed rotor 36 Is provided with a liner 34 (there is no need to have a groove on the liner surface), a classification rotor 31 that is a means for classifying the surface-modified raw material into a predetermined particle size, and a cold air A cold air introduction port 35 for introducing the raw material, a raw material supply port 33 for introducing the raw material to be treated, and a discharge valve 38 installed so as to be openable and closable so that the surface modification time can be freely adjusted. ,place A powder discharge port 37 for discharging the subsequent powder, and a space between the classification rotor 31 as the classification means and the dispersion rotor 36 and the liner 34 as the surface modification means are introduced into the classification means. It is composed of a front first space 41 and a cylindrical guide ring 39 which is a guide means for partitioning the particles, from which fine powder has been classified and removed by the classification means, into a second space 42 for introducing the particles into the surface modification means. ing. A gap portion between the dispersion rotor 36 and the liner 34 is a surface modification zone, and a classification rotor 31 and a rotor peripheral portion are classification zones.

  As shown in FIG. 1, the classifying rotor 31 may be installed vertically or horizontally. Further, the number of classification rotors 31 may be single as shown in FIG. 1 or plural.

  In the surface reforming apparatus configured as described above, when the raw material toner particles are introduced from the raw material supply port 33 with the discharge valve 38 closed, the introduced raw material toner particles are first drawn by a blower (not shown). Suctioned and classified by the classification rotor 31. At that time, the classified fine powder having a predetermined particle diameter or less is continuously discharged and removed out of the apparatus, and the coarse powder having a predetermined particle diameter or more passes along the inner periphery (second space 42) of the guide ring 39 by centrifugal force. The circulating flow generated by the dispersion rotor 36 is guided to the surface modification zone. The raw material guided to the surface modification zone is subjected to a surface modification treatment by receiving a mechanical impact force between the dispersion rotor 36 and the liner 34. The surface-modified particles having undergone surface modification are guided to the classification zone along the outer periphery (first space 41) of the guide ring 39 on the cold air passing through the inside of the machine. The coarse powder discharged to the outside of the machine is put into a circulating flow, returned to the surface modification zone again, and repeatedly subjected to the surface modification action. After a certain period of time, the discharge valve 38 is opened and the surface modified particles are recovered from the discharge port 37.

  In the present invention, the fine particle component can be removed simultaneously with the surface modification of the toner particles in the toner particle surface modification step. As a result, the ultrafine particles present in the toner particles do not adhere to the surface of the toner particles, and toner particles having a desired circularity and an ultrafine particle amount can be obtained effectively. If fine powder cannot be removed at the same time as surface modification, there will be a large amount of ultrafine particles in the toner particles after surface modification, and mechanical and thermal effects will occur in the toner particle surface modification process. As a result, the ultrafine particle component adheres to the surface of the toner particles having an appropriate particle size. As a result, protrusions due to the adhering fine powder component are generated on the surface of the toner particles, and toner particles having a desired circularity cannot be obtained.

  As a result of the study by the present inventors, the surface modification time (= cycle time) in the surface modification apparatus is preferably 5 seconds or more and 180 seconds or less, more preferably 15 seconds or more and 120 seconds or less. When the surface modification time is less than 5 seconds, the modification time is too short, and thus the surface modified toner particles may not be sufficiently obtained. Further, if the reforming time exceeds 180 seconds, the reforming time is too long, which may cause in-machine fusion due to heat generated during surface reforming and decrease in processing capacity.

  Furthermore, in the method for producing toner particles of the present invention, it is preferable that the cold air temperature T1 introduced into the surface modifying apparatus is 5 ° C. or less. By setting the cold air temperature T1 introduced into the surface reforming apparatus to 5 ° C. or less, more preferably 0 ° C. or less, and even more preferably −5 ° C. or less, in-machine fusion due to heat generated during surface modification is achieved. Can be prevented. When the cold air temperature T1 introduced into the surface reforming apparatus exceeds 5 ° C., in-machine fusion may occur due to heat generated during the surface modification.

  In addition, it is preferable that the cold air introduce | transduced in this surface modification apparatus is dehumidified from the surface of the dew condensation prevention in an apparatus. A well-known thing can be used as a dehumidifier. The supply air dew point temperature is preferably −15 ° C. or lower, and more preferably −20 ° C. or lower.

  Furthermore, in the method for producing toner particles of the present invention, the inside of the surface modifying device is provided with a jacket for cooling the inside of the apparatus, and a refrigerant (preferably cooling water, more preferably an antifreeze liquid such as ethylene glycol) is provided in the jacket. It is preferable to carry out surface modification treatment while passing through. In-machine cooling by the jacket can prevent in-machine fusion due to heat during the toner particle surface modification.

  In addition, it is preferable that the temperature of the refrigerant | coolant passed through this jacket of a surface modification apparatus shall be 5 degrees C or less. By setting the temperature of the refrigerant passed through the jacket in the surface reforming apparatus to 5 ° C. or less, more preferably 0 ° C. or less, and even more preferably −5 ° C. or less, in-machine melting due to heat generated during surface reforming is performed. Wearing can be prevented. When the temperature of the refrigerant introduced into the jacket exceeds 5 ° C., in-machine fusion may occur due to heat generated during surface modification.

  Furthermore, in the method for producing toner particles of the present invention, it is preferable that the temperature T2 behind the classification rotor in the surface modifying apparatus is 60 ° C. or less. By setting the temperature T2 behind the classification rotor in the surface reforming apparatus to 60 ° C. or less, preferably 50 ° C. or less, in-machine fusion due to heat generated during the surface modification can be prevented. When the temperature T2 behind the classification rotor in the surface reformer exceeds 60 ° C., the temperature is further affected in the surface reforming zone. Therefore, in-machine fusion is caused by heat generated during the surface reforming. There is.

  Furthermore, in the method for producing toner particles of the present invention, the minimum distance between the dispersion rotor and the liner in the surface modifying apparatus is preferably 0.5 mm to 15.0 mm, and more preferably 1.0 mm. It is preferable to be set to 10.0 mm. In addition, the rotational peripheral speed of the dispersion rotor is preferably 75 m / sec to 200 m / sec, and more preferably 85 m / sec to 180 m / sec. Further, the minimum distance between the upper part of the rectangular disk or cylindrical pin installed on the upper surface of the dispersion rotor in the surface modifying apparatus and the lower part of the cylindrical guide ring is 2.0 mm to 50 mm. 0.0 mm is preferable, and 5.0 mm to 45.0 mm is more preferable.

  In the present invention, it is preferable in terms of toner particle productivity that the pulverized surfaces of the dispersion rotor, the square disk, or the cylindrical pin and the liner in the surface modifying apparatus are subjected to abrasion resistance treatment. As the base material of the pin and the liner, carbon steel such as S54C or chromium molybdenum steel such as SCM material is often used, but there is a problem in wear resistance performance as it is. By coating with plating having wear resistance, the surface hardness is large and the wear resistance is high. The type of plating used in the present invention is not particularly limited as long as it has the abrasion resistance necessary for the surface treatment of the toner. For example, nickel plating, chromium plating, rhodium plating, ruthenium plating, and these are multilayered. It is possible to use multilayer plating or the like stacked on top of each other. Chromium plating (hard chromium plating) is preferable from the viewpoint of excellent wear resistance, and chromium alloy plating containing at least chromium carbide is particularly preferably used. Chromium carbide having a strong intermolecular bonding force present in the chromium alloy can improve the adhesion to the surface of the base material, and can reduce the occurrence frequency of phenomena such as peeling and cracking as much as possible.

  The blade shape of the dispersion rotor and liner in the surface modification apparatus is not limited at all.

  In the toner particle production method of the present invention, the raw material toner particles finely divided in the vicinity of a desired particle diameter are removed to some extent by using an airflow classifier, and then the toner is produced by a surface modification device. It is preferable to perform surface modification of the particles and removal of the ultrafine powder component. By removing the fine powder in advance, the dispersion of the toner particles in the surface modifying apparatus becomes good. In particular, the fine powder component in the toner particles has a large specific surface area and a relatively high charge amount compared to other large toner particles, so it is difficult to separate from other toner particles, and it can be appropriately exceeded by a classification rotor. Although the fine powder component may not be classified, by removing the fine powder component in the toner particles in advance, the individual toner particles can be easily dispersed in the surface reforming device, and the ultra fine powder component is properly classified by the classification rotor. Toner particles having a desired particle size distribution can be obtained. In the toner from which fine powder has been removed by an airflow classifier, the cumulative value of the number average particle size distribution of toner particles of less than 4 μm in a particle size distribution measured using a Coulter counter method is 10% to 50%. Is preferably 15% or more and less than 45%, more preferably 15% or more and less than 40%, and the ultrafine powder component can be effectively removed by the surface modification apparatus of the present invention. . Examples of the airflow classifier used in the present invention include elbow jet (manufactured by Nippon Steel Industries Co., Ltd.).

  In the present invention, the magnetic material is used in an amount of 20 to 200 parts by mass with respect to 100 parts by mass of the binder resin. Preferably it is used at 50 to 130 parts by mass.

  In the present invention, the magnetic material used for the magnetic toner contains Si element in an amount of 0.3 to 0.9% by mass based on the magnetic material, and Mn, Zn, Cu, Al and Mg as metal elements other than iron. One of the characteristics is that it contains 0.4 to 1.2% by mass of one or more metal elements (other metal elements) selected from the group consisting of:

  In this invention, the fluidity | liquidity of a magnetic body can be improved by containing Si element in a magnetic body. The Si element should be contained in an amount of 0.3 to 0.9 mass%, preferably 0.4 to 0.8 mass%, based on the magnetic material. When the Si element is less than 0.3% by mass, sufficient fluidity cannot be obtained, and aggregation is likely to occur and developability is deteriorated. If the Si element is greater than 0.9% by mass, the effect of improving electric resistance, residual magnetization, coercive force, and fluidity can be sufficiently obtained, but developability deteriorates due to moisture absorption under high humidity.

  By using other kinds of metal elements together with the Si element, the fluidity, chargeability, hygroscopicity, and magnetic properties of the magnetic material can be improved. The other kinds of metal elements are contained in an amount of 0.4 to 1.2% by mass, preferably 0.6 to 1.0% by mass based on the magnetic substance. If the content is less than 0.4% by mass, the effect of improving the fluidity is small, and if it is more than 1.2% by mass, the electrical resistance increases and adversely affects the charging characteristics of the toner.

  In the present invention, the number average particle size of the magnetic material is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.4 μm. When the number average particle diameter of the magnetic material is smaller than 0.05 μm, the adhesive force between the magnetic particles is increased, and the dispersibility in the binder resin is deteriorated. When the number average particle diameter of the magnetic material is larger than 1.0 μm, the number of magnetic particles contained in the toner is reduced, so that the dispersion of the magnetic material in the binder resin is likely to be biased and charged. Uniformity is impaired.

When the BET specific surface area of the magnetic material is 7 to 16 m ² / g, the environmental stability of development is improved.

  The number average particle diameter can be determined by measuring a photograph taken with a transmission electron microscope or the like with a digitizer or the like.

  According to the BET method, the BET specific surface area can be calculated by adsorbing nitrogen gas to the sample surface using a specific surface area measuring device Auto Soap 1 (manufactured by Yuasa Ionics) and using the BET multipoint method. .

The magnetic material of the present invention is required to have a saturation magnetization of 40 to 110 Am ² / kg, preferably 70 to 100 Am ² / kg at a magnetic field of 795.8 kA / m. This is because magnetic toner can be prevented from leaking by providing a magnetic force generating means in the developing device, and not only can the magnetic toner be transported or stirred, but also the magnetic toner can form spikes. It becomes easy to prevent scattering. However, if the saturation magnetization of the magnetic material at a magnetic field of 795.8 kA / m is less than 40 Am ² / kg, the above effect cannot be obtained, and if magnetic force is applied to the magnetic toner carrier, the magnetic toner does not stand up. It becomes stable, and fog and image density unevenness are likely to occur due to the inability to uniformly charge the magnetic toner. On the other hand, when the saturation magnetization of the magnetic material at a magnetic field of 795.8 kA / m is larger than 110 Am ² / kg, when magnetic force is applied to the magnetic toner, the fluidity of the magnetic toner is remarkably lowered due to magnetic aggregation, and the developability is lowered. , The magnetic toner is easily damaged, and toner deterioration is remarkable. Further, due to the magnetic aggregation of the magnetic toner, the durability under high temperature and high humidity is inferior.

The magnetic material preferably has a remanent magnetization of ² to 8 Am ² / kg at a magnetic field of 79.6 kA / m. When the residual magnetization is less than ² Am ² / kg, the transfer residual toner is likely to be present in a state of being dispersed in each particle, and is difficult to be captured by the charging member, and as a result, it may be difficult to be charged normally. It is not preferable. On the other hand, when the residual magnetization exceeds 8 Am ² / kg, the transfer residual toner is magnetically aggregated and easily acts as an aggregate of toner, and is rubbed between the charging member and the photosensitive member, thereby causing the surface of the photosensitive member to be rubbed. May be hurt. In other words, since the magnetic toner has a preferable residual magnetization, the transfer residual toner exists in an appropriately aggregated state, so that it is made appropriate without damaging the photoreceptor.

  When the coercive force of the magnetic substance at a magnetic field of 79.6 kA / m is 5 to 8 kA / m, a high-quality image can be obtained.

  The magnetization strength (saturation magnetization, residual magnetization, coercive force) of the magnetic toner can be arbitrarily changed by the amount of magnetic powder contained, the saturation magnetization, the residual magnetization, and the coercive force of the magnetic powder. In the present invention, the saturation magnetization, residual magnetization, and coercive force of the magnetic toner can be measured using, for example, a vibration magnetometer VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.). In the case of using the above apparatus, the measurement is performed at a room temperature of 25 ° C. with an external magnetic field of 79.6 kA / m. Also, the magnetic properties of the magnetic powder can be measured using a vibration magnetometer VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.) at a room temperature of 25 ° C. and an external magnetic field of 796 kA / m.

  In the surface modifying apparatus used in the present invention, the raw material guided to the surface modifying zone during the surface modification of the toner particles is subjected to a surface modification treatment by receiving a mechanical impact force between the dispersion rotor and the liner. Since the toner particles are subjected to a strong impact on the surface during the surface treatment, the binder resin or wax having elasticity on the surface of the toner particles is scraped, and a part of the magnetic particles covered with the binder resin or wax is accompanied accordingly. Are exposed on the surface of the toner particles. Since the surface treatment is performed while cutting the ultrafine powder, there is no adhesion or embedding of the ultrafine powder on the surface of the toner particles.

  In a solution in which 40 mg of the toner of the present invention was dispersed in 5 ml of an aqueous surfactant solution and 5 ml of 6 mol / l hydrochloric acid was added to extract the surface magnetic material of the toner for 30 minutes, the absorbance at 340 nm derived from the magnetic material was 2 .30 to 3.50, preferably 2.40 to 3.30, more preferably 2.50 to 3.20, and even more preferably 2.55 to 3.10, with respect to toner blocking resistance. The toner does not deteriorate even when used for a long time under high temperature and high humidity.

  When the absorbance at 340 nm absorption derived from the magnetic material is larger than 3.50, this indicates that the magnetic material is increased on the surface of the toner particles. When the exposed amount of the magnetic material on the toner surface is large, the hygroscopicity of the toner becomes strong, which adversely affects developability and durability.

  On the other hand, when the absorbance at 340 nm of absorption derived from the magnetic material is smaller than 2.30, this indicates that the magnetic material is hardly exposed on the surface of the toner particles. That is, the ratio of binder resin and wax is large on the toner surface. For this reason, the fluidity of the toner is lowered, so that the dot reproducibility is deteriorated and the developability is deteriorated.

The absorbance of the present invention is the common logarithm of the reciprocal of the transmittance I / I ₀ , which is the difference between the intensity I ₀ of the incident light and the intensity I of the transmitted light when the light is incident on the sample cell ( I ₀ / I).

  The abundance of the magnetic substance on the toner particle surface in the present invention is determined as follows.

<Measurement of the amount of magnetic material on the toner surface>
A dispersant prepared by adding 1.23 vol% of a surfactant, preferably an alkylbenzene sulfonate, to water from which impurities in the container have been removed in advance is prepared. Place 40 mg of sample in a sample bottle and add 5 ml of dispersant to fully disperse the sample. Subsequently, 5 ml of 6 mol / l hydrochloric acid is added and left for 30 minutes.

  The solution after being allowed to pass is passed through a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corp., Excro Disc 25CR manufactured by Gelman Science Japan Ltd., etc.). A sample for absorbance measurement.

  The filtrate is measured with a spectrophotometer (for example, Shimadzu UV-3100PC). At this time, a mixed solution of 5 ml of the dispersant and 5 ml of 6 mol / l hydrochloric acid is put in a control cell.

  Measurement conditions: scan speed (medium speed), slit width (0.5 nm), sampling pitch (2 nm), measurement range (600 to 250 nm)

  In the surface reforming apparatus used in the present invention, the raw material guided to the surface modification zone during the surface modification of the toner is subjected to a surface modification treatment by receiving a mechanical impact force between the dispersion rotor and the liner. Since the toner particles are subjected to a strong impact on the surface during the surface treatment, the binder resin or wax having elasticity on the surface of the toner particles is scraped, and a part of the magnetic particles covered with the binder resin or wax is accompanied accordingly. Are exposed on the surface of the toner particles. Therefore, the ratio of the magnetic material is relatively increased on the toner particle surface. In the toner particles of the present invention, the binder and resin on the surface of the toner particles are scraped to expose the magnetic body, so that the majority of the magnetic body is buried and only a part is exposed on the surface. Exists. If such a magnetic material is dissolved only with hydrochloric acid, it will be greatly affected by the hydrophobic binder resin and wax in the vicinity, and it cannot be adequately adjusted with hydrochloric acid alone. It is difficult to know the amount of magnetic material accurately. In order to accurately determine the surface magnetic substance amount of the toner of the present invention having such a surface state, it is effective to add a surfactant to hydrochloric acid.

  In a toner having a circularity as in the present invention, a magnetic material is exposed on the surface of the toner by a surface modification treatment, so that an image can be obtained under a high temperature and high humidity even for a long time using a high speed machine with a process speed of 200 mm / sec. It has been discovered that flow and drum fusion can prevent the occurrence of white streaks (streaks are formed on the drum surface and white streaks appear on the image) under low temperature and low humidity.

  A toner having a high average circularity as in the present invention can take a very tightly packed state on the drum. Further, since the magnetic material of the toner of the present invention is exposed on the surface, the magnetic material serves as an abrasive, and the drum surface can be evenly shaved. As an effect of this, even in long-term use with a high-speed machine with a process speed of 200 mm / sec, image flow and drum fusion are performed under high temperature and high humidity, and white stripes (streaks are formed on the drum surface and images are formed on the drum surface). The occurrence of white stripes) can be prevented.

  If the absorbance of the magnetic material eluted from the toner surface is greater than 3.50, the magnetic material in contact with the drum surface will increase, making it difficult to polish the drum surface uniformly and causing unevenness in the shaving. Embedding causes drum fusion and affects the image. When the absorbance due to the magnetic material eluted from the toner surface is less than 2.30, the magnetic material in contact with the drum surface decreases, and the polishing effect of the drum decreases, resulting in image flow and white streaks. Also, poor cleaning due to slipping and drum fusion due to wax are likely to occur.

  Furthermore, by appropriately adding the above metal to the magnetic material, it has become possible to prevent tailing under high temperature and high humidity even in long-term use with a high speed machine having a process speed of 200 mm / sec. In the magnetic material, Si element is 0.3 to 0.9 mass% based on the magnetic material, and one or more other metal elements, preferably Zn element is 0.4 to 1.2 mass based on the magnetic material. In addition, the fluidity of the magnetic material can be improved and an appropriate surface resistance can be imparted. Since the toner of the present invention has a high degree of circularity, dense toner spikes are generated on the sleeve by magnetic force during development. When the magnetic material has an appropriate surface resistance, charge leakage hardly occurs even in a dense toner state, and a spike having a stable charge can be formed. In line images, tailing of the back edge of the image may occur due to toner ears. However, if the magnetic substance has high fluidity, the toner ears are easily loosened in dense toner ears formed by magnetic force. Since only the toner necessary for development can fly to the drum, tailing does not occur.

  If the Si element in the magnetic material is less than 0.3% by mass, or if one or more kinds of other metal elements are less than 0.4% by mass, the magnetic material loses fluidity, and in the ears of the toner formed by magnetic force, The magnetic cohesion between the toners is excellent, and tailing occurs because the ears fly to the drum without being loosened. If the Si element in the magnetic material is more than 0.9% by mass, or if one or more kinds of other metal elements are more than 1.2% by mass, the electric resistance of the toner becomes too high and the toner spike formed by magnetic force. In this case, the electrostatic cohesive force between the toners becomes strong, and tailing occurs because the ears fly to the drum without being loosened.

  The average circularity is high, the magnetic material is exposed on the toner surface, and the magnetic material contains Si element and one or more other metal elements, so that the tribo is uniform on the sleeve and has excellent fluidity. A toner layer can be formed. When developing a line drawing of a character or the like, the electrostatic latent image of the line drawing of a character or the like tends to concentrate an electric field on the edge due to the edge effect. The toner having a small particle diameter has a characteristic that it is easily developed by being concentrated on an edge portion of a character or the like. Therefore, if there are many ultra fine particles having a particle size of 0.6 μm or more and less than 3 μm in the toner particles, the ultra fine particles having a particle size of 0.6 μm or more and less than 3 μm are likely to be concentrated and developed on the edge portion of characters, etc. There is a difference in image density between the edge portion and the middle portion of the electrostatic latent image such as characters. As in the present invention, when the amount of ultrafine powder having a particle size of 0.6 μm or more and less than 3 μm is small in the toner, the toner having uniform tribo and excellent fluidity is suitable for an electrostatic latent image without receiving an edge effect. Can fly uniformly and can faithfully reproduce an electrostatic latent image.

  When the toner particle ratio of 0.6 μm or more and less than 3 μm is more than 20% by number, when a line drawing such as a character is developed, an edge effect appears greatly, and an extreme difference occurs in the image density between the edge portion and the middle portion of the character. .

  The toner of the present invention contains a magnetic material. The magnetic material can also serve as a colorant. The structure and manufacturing method of the magnetic material used in the present invention will be described.

  The magnetic body containing a silicon element according to the present invention is manufactured, for example, by the following method. After adding a predetermined amount of one or more metal salts and silicates selected from Mn, Zn, Cu, Al and Mg to the ferrous salt aqueous solution, an alkali such as sodium hydroxide having an equivalent amount or more with respect to the iron component Is added to prepare an aqueous solution containing ferrous hydroxide. While maintaining the pH of the prepared aqueous solution at pH 7 or higher (preferably pH 8 to 10), air was blown in, and the aqueous solution was heated to 70 ° C. or higher to oxidize ferrous hydroxide. First, a seed crystal is formed.

  Next, an aqueous solution containing a first equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. While maintaining the pH of the liquid at 6 to 10, the reaction of ferrous hydroxide is promoted while blowing air, and the magnetic particles are grown with the seed crystal as the core. As the oxidation reaction proceeds, the pH of the liquid shifts to the acidic side, but the pH of the liquid is preferably not less than 6. By adjusting the pH of the solution at the end of the oxidation reaction, it is preferable to disperse a predetermined amount of another metal compound on the surface layer and surface of the magnetic particles.

  Examples of the silicate used for the addition include sodium silicate and potassium silicate. As metal salts other than iron used for addition, sulfates, nitrates, and chlorides can be used. As the ferrous salt, it is possible to use iron sulfate generally produced as a by-product in the production of sulfuric acid titanium, iron sulfate produced as a by-product when the surface of the copper plate is washed, and iron chloride can be used.

  In the method for producing a magnetic substance by the aqueous solution method, generally, an iron concentration of 0.5 to 2 mol / liter is used from the viewpoint of preventing an increase in viscosity during the reaction and the solubility of iron sulfate. Generally, the lower the iron sulfate concentration, the finer the particle size of the product. In the reaction, the larger the amount of air and the lower the reaction temperature, the easier the atomization.

  According to the above-described manufacturing method, magnetic particles having a silicate element and other types of metal elements are mainly composed of spherical particles formed with a curved surface having no plate-like surface, as observed by transmission electron micrographs. It is preferable to produce a magnetic material containing almost no octahedral particles and use the magnetic material in a magnetic toner.

  Other colorants that can be used in the toner of the present invention include any suitable pigment or dye. Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, Bengala, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient to maintain the optical density of the fixed image, and an addition amount of 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass is good with respect to 100 parts by mass of the binder resin. . Examples of the dye include azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes. The addition amount of the dye is 0.1 to 20 parts by mass, preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  As the types of binder resins used in the present invention, styrene resins, styrene copolymer resins, polyester resins, polyol resins, polyvinyl chloride resins, phenol resins, natural modified phenol resins, natural resin modified maleic resins, Examples thereof include acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, and petroleum resin.

  As a comonomer for the styrene monomer of the styrene copolymer, a styrene derivative such as vinyltoluene; acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, acrylic Acrylic acid ester such as phenyl acid; Methacrylic acid ester such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate; Maleic acid; Double such as butyl maleate, methyl maleate, dimethyl maleate Dicarboxylic acid ester having a bond; acrylamide, acrylonitrile, methacrylonitrile, butadiene; vinyl ester such as vinyl chloride, vinyl acetate, vinyl benzoate; ethylene, propylene, butylene Such ethylenic olefins, vinyl methyl ketone, such as vinyl vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl propionate ether. These vinyl monomers are used alone or in combination of two or more.

  In the present invention, a styrene-acrylic acid ester-acrylic acid copolymer, a styrene-acrylic acid ester copolymer, and a styrene-acrylic acid ester-methacrylic acid copolymer are used as a particularly preferable binder resin, whereby toner It becomes easy to control the circularity of the particles to an appropriate value.

  In the present invention, the toner preferably contains a “vinyl resin having a carboxyl group” and a “vinyl resin having a bond formed by a reaction of a carboxyl group and an epoxy group as a partial structure” as a binder resin. preferable. By adopting such a resin structure, higher charging performance can be obtained, and a stable image can be obtained over a long period of time without lowering the image density. This is because the residual carboxyl group having negative polarity in the binder resin or the ester portion formed by the reaction of the carboxyl group and the epoxy group interacts with each other on the toner particle surface with the resin or the negative charge control agent. This is for improving the dispersion state of the resin and the negative charge control agent.

  "Vinyl resin having a bond formed by the reaction of a carboxyl group and an epoxy group as a partial structure" used as a binder resin is a carboxyl group and an epoxy group in a vinyl resin having a carboxyl group and a vinyl resin having an epoxy group. Are preferably bonded to each other, or are bonded to a carboxyl group and an epoxy group in a vinyl resin having a carboxyl group and an epoxy group, and the former is more preferable.

  For example, in the case of using a compound having a glycidyl group as an epoxy group, the “bond formed by the reaction of a carboxyl group and an epoxy group”

となり、架橋構造を形成するものである。

Thus, a crosslinked structure is formed.

  A single unit having a carboxyl group that can be used to obtain a “vinyl resin having a carboxyl group” or a “vinyl resin having a bond formed by a reaction between a carboxyl group and an epoxy group” according to the present invention. Examples of the monomer include the following. For example, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, cinnamic acid, vinyl acetic acid, isocrotonic acid, tiglic acid and angelic acid; α- or of these unsaturated monocarboxylic acids β-alkyl derivatives; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, alkenyl succinic acid, itaconic acid, mesaconic acid, dimethylmaleic acid, dimethylfumaric acid; monoester derivatives of unsaturated dicarboxylic acids, anhydrides and α- or β-alkyl derivatives may be mentioned. The above-mentioned monomers having a carboxyl group can be used alone or in combination, and can also be used by copolymerizing with other vinyl monomers by a known polymerization method.

  Next, the vinyl resin having an epoxy group used when obtaining “a vinyl resin having a bond formed by a reaction between a carboxyl group and an epoxy group as a partial structure” will be described. The epoxy group in the present invention is a functional group in which an oxygen atom is bonded to different carbon atoms in the same molecule to form a cyclic ether structure.

  Examples of the monomer having an epoxy group that can be used in the present invention include the following.

  Examples include glycidyl acrylate, glycidyl methacrylate, β-methyl glycidyl acrylate, β-methyl glycidyl methacrylate, allyl glycidyl ether, and allyl β-methyl glycidyl ether. Moreover, the glycidyl monomer represented by General formula (1) is used preferably.

（一般式（１）において、Ｒ₁、Ｒ₂及びＲ₃は、水素原子、又は、アルキル基、アリール基、アラルキル基、カルボキシル基及びアルコシキカルボニル基からなるグループより選ばれる官能基を示す。）

In (formula _{(1), R 1, R} 2 and R ₃ is a hydrogen atom or represents an alkyl group, an aryl group, an aralkyl group, a functional group selected from the group consisting of carboxyl group and an alkoxycarbonyl group. )

  Such a monomer having an epoxy group may be polymerized singly or as a mixture of a plurality of types, or by copolymerizing with other vinyl monomers by a known polymerization method. A vinyl resin having a group can be obtained.

  The vinyl resin having a carboxyl group and an epoxy group can be obtained by mixing a monomer having a carboxyl group and a monomer having an epoxy group, and copolymerizing with another vinyl monomer by a known polymerization method.

The binder resin used in the present invention has a glass transition temperature (Tg) of 45 to 80 ° C, preferably 50 to 70 ° C, from the viewpoint of storage stability. When Tg is lower than 45 ° C., it tends to cause toner deterioration under a high temperature atmosphere and offset during fixing. On the other hand, when Tg exceeds 80 ° C., fixability tends to decrease.
・ Glass transition point (Tg)
The temperature at the intersection of the DSC curve and the line connecting the midpoints of the baseline before and after the change in specific heat appears in the DSC curve during temperature rise.

  The measuring method of Tg is performed according to ASTM D3418-82 using Q-1000 manufactured by TA Instruments. The DSC curve used in the present invention is a DSC curve that is measured when the temperature is raised at a rate of 10 ° C./min after raising and lowering the temperature once and taking a previous history. The definition is as follows.

  Examples of the polymerization method of the binder resin of the present invention include a solution polymerization method, an emulsion polymerization method and a suspension polymerization method.

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

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

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

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

  Specifically, benzoyl peroxide, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di (t-butylperoxy) valerate, dichroic Organic peroxides such as milperoxide, α, α'-bis (t-butylperoxydiisopropyl) benzene, t-butylperoxycumene, di-t-butylperoxide; azobisisobutyronitrile, diazoamino Examples include azo and diazo compounds such as azobenzene.

  These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator, but in order to keep the efficiency of the polyfunctional polymerization initiator appropriate, in the polymerization step, It is preferably added after the half-life indicated by the polyfunctional polymerization initiator has elapsed.

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

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

  As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. Specific examples include aromatic divinyl compounds (eg, divinylbenzene, divinylnaphthalene, etc.); diacrylate compounds linked by alkyl chains (eg, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4 -Butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylate); alkyl chain containing an ether bond Diacrylate compounds (eg, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, Ethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds in place of methacrylate); diacrylate compounds linked by a chain containing an aromatic group and an ether bond (eg, polyoxyethylene) (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and methacrylates of the above compounds Furthermore, polyester-type diacrylate compounds (for example, trade name MANDA (Nippon Kayaku)) are mentioned. As polyfunctional crosslinking agents, pentaerythritol acrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds are replaced with methacrylate. Triallyl cyanurate, triallyl trimellitate; and the like.

  These crosslinking agents are preferably used in the range of 0.00001 to 1 part by mass, preferably 0.001 to 0.05 part by mass, with respect to 100 parts by mass of the other monomer components.

  As a method for producing a binder resin composition, a high-molecular weight polymer and a low-molecular weight polymer are separately synthesized by a solution polymerization method, mixed in a solution state, and then desolvated, and an extruder. The resin composition is prepared by dissolving in a monomer constituting a high molecular weight polymer obtained by dissolving a low molecular weight polymer obtained by a melt blending method such as a melt blending method, a solution polymerization method, etc., and performing suspension polymerization, washing and drying. And a two-stage polymerization method for obtaining However, the dry blend method has a point to be improved in terms of uniform dispersion and compatibility. The two-stage polymerization method has many advantages such as uniform dispersibility, but the low molecular weight can be increased to higher than the high molecular weight, and a high molecular weight polymer with a large molecular weight can be synthesized. The solution blending method is most suitable because there are few problems that coalescence is formed as a by-product. In addition, when a predetermined acid value is introduced into the low molecular weight polymer component, solution polymerization is preferred in which the acid value can be easily set as compared with a polymerization method using an aqueous medium.

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

  Examples of the toner that controls the negative charge include the following compounds.

  For example, organometallic complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Others include aromatic hydroxycarboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

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

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

  Alternatively, a basic organic acid metal complex represented by the following general formula (2) is also preferable as a charge control agent that imparts negative chargeability.

  In particular, Fe, Cr, Si, Zn or Al is preferred as the central metal, alkyl groups, anilide groups, aryl groups and halogens are preferred as substituents, and hydrogen, ammonium and aliphatic ammonium are preferred as counter ions.

  The following compounds are used to control the toner to be positively charged.

  Modifications with nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts thereof And these lake pigments, triphenylmethane dyes and these lake pigments. Metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyl Such diorgano tin borate of Suzuboreto; 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. Moreover, general formula (3)

［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。］
で表わされるモノマーの単重合体：前述したスチレン、アクリル酸エステル、メタクリル酸エステルの如き重合性モノマーとの共重合体を正荷電性制御剤として用いることができる。この場合これらの荷電制御剤は、結着樹脂（の全部または一部）としての作用をも有する。

[Wherein R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably C _{1 to} C ₄ ). ]
Monomers of monomers represented by: A copolymer with a polymerizable monomer such as styrene, acrylic acid ester or methacrylic acid ester described above 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).

  In particular, a compound represented by the following general formula (4) is preferred as the positive charge control agent of the present invention.

  Specific product names include nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

  Preferred for negative charging are, for example, Spiron Black TRH, T-77, T-95 (Hodogaya Chemical), BONTRON (registered trademark) S-34, S-44, S-54, E-84, E- 88, E-89 (Orient Chemical Co., Ltd.), and preferable examples for positive charging include TP-302, TP-415 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) N-01, N- 04, N-07, P-51 (Orient Chemical), and Copy Blue PR (Clariant).

  As a method for incorporating the charge control agent into the toner, there are a method of adding it inside the toner particles and a method of adding it outside the toner particles. The amount of use of these charge control agents is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 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.

  The toner of the present invention may contain a wax. The waxes used in the present invention include the following. For example, paraffin wax and derivatives thereof, montan wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, carnauba wax and derivatives thereof, and the like. Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. The toner of the present invention preferably contains at least a polar wax. Because the wax has polarity, compatibility with the binder resin can be increased, and the wax can be dispersed in the binder resin in the form of fine particles during heat kneading and does not segregate. At this time, it is possible to uniformly expose the magnetic body. If the wax is non-polar, the compatibility with the binder resin will be poor and segregation will occur during thermal kneading. It becomes difficult to let you. As the polar wax, an alcohol-modified paraffin wax obtained by hydrolyzing a paraffin wax oxide is particularly preferably used.

  Specific examples of the wax include Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), high wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals), Sasol H1, H2, C80, C105, C77 (Schumann-Sasol), HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP- 12 (Nippon Seiki Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark), Unicid (registered trademark) 350, 425, 550, 700 (Toyo Petrolite Co., Ltd.), Kirou, Beeswax, rice wax, candelilla wax, carnauba wax (available at Celerica NODA Inc.) And the like.

  In the toner of the present invention, the total content of these waxes is 0.1 to 15 parts by mass, preferably 0.5 to 12 parts by mass with respect to 100 parts by mass of the binder resin. It is.

  These waxes have a melting point measured using a differential thermal analyzer (DSC) of 65 ° C. or higher and lower than 130 ° C., preferably 70 ° C. or higher and lower than 120 ° C., more preferably 70 ° C. or higher and lower than 110 ° C., more preferably. It is preferable that it is 75 degreeC or more and less than 100 degreeC. The wax having such a melting point in the toner particles has an appropriate hardness, and the toner particles having the desired circularity, particle size distribution, and surface roughness are effectively used in the surface modification process of the toner particles. Obtainable. When the melting point of the wax is less than 65 degrees, the storage stability of the toner may be deteriorated. When the melting point of the wax exceeds 130 ° C., the toner particles become too hard and the productivity of the surface-modified toner may deteriorate.

<Measurement method of melting point of wax>
Sample: 0.5-2 mg, preferably 1 mg
Measurement method: Place the sample in an aluminum pan, and use an empty aluminum pan as a reference.
Temperature curve: Temperature increase I (20 ° C. to 180 ° C., temperature increase rate 10 ° C./min)
Temperature drop I (180 ° C. to 10 ° C., temperature drop rate 10 ° C./min)
Temperature increase II (10 ° C to 180 ° C, temperature increase rate 10 ° C / min)
The endothermic peak temperature measured at the temperature elevation II in the temperature curve is defined as the melting point.

  The toner particles of the present invention are preferably externally added with inorganic fine powder or hydrophobic inorganic fine powder. For example, silica fine powder, titanium oxide fine powder, or a hydrophobized product thereof can be used. They are preferably used alone or in combination.

  Examples of the silica fine powder include both a dry process produced by vapor phase oxidation of a silicon halogen compound or dry silica called fumed silica, and wet silica produced from water glass or the like. Dry silica with fewer silanol groups on the surface and inside and no production residue is preferred.

  Further, the silica fine powder is preferably hydrophobized. Hydrophobizing treatment is performed by chemically treating with an organosilicon compound that reacts or physically adsorbs with silica fine powder. Preferable methods include a method in which a dry silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with a silane compound or with a silane compound and simultaneously with an organosilicon compound such as silicone oil.

  The silane compounds used for the hydrophobization treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethyl. Chlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane , Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldi Examples thereof include siloxane and 1,3-diphenyltetramethyldisiloxane.

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

  Silicone oil treatment can be performed by directly mixing silica powder treated with a silane compound and silicone oil using a mixer such as a Henschel mixer, or by spraying silicone oil onto the base silica. Also good. Alternatively, the silicone oil may be dissolved or dispersed in an appropriate solvent, and then mixed with the base silica fine powder to remove the solvent.

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

  As described above, it is preferable to treat the silica fine powder with the silane compound and then oil-treat it later, so that the degree of hydrophobicity can be effectively increased.

  The silica fine powder is preferably subjected to a hydrophobization treatment, and further, an oil treatment applied to the titanium oxide fine powder, similarly to the silica-based one.

  To the toner particles of the present invention, additives other than silica fine powder or titanium oxide fine powder may be externally added as necessary.

  Examples thereof include resin fine particles and inorganic fine particles that act as charging aids, conductivity imparting agents, fluidity imparting agents, anti-caking agents, mold release agents at the time of hot roll fixing, lubricants, and abrasives.

  The fine resin particles preferably have an average particle size of 0.03 to 1.0 μm. As the polymerizable monomer constituting the resin, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene derivatives; acrylic acid; methacrylic acid; methyl acrylate , Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate Acrylic acid esters such as: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, Lil, phenyl methacrylate, dimethylaminoethyl methacrylate, such as methacrylic acid esters of diethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, and the like monomers acrylamide.

  Examples of the polymerization method include suspension polymerization, emulsion polymerization, and soap-free polymerization. More preferably, particles obtained by soap-free polymerization are good.

  Other fine particles include lubricants such as polyethylene fluoride, zinc stearate and polyvinylidene fluoride (in particular, polyvinylidene fluoride is preferred); abrasives such as cerium oxide, silicon carbide and strontium titanate (especially strontium titanate). Fluidity-imparting agents such as titanium oxide and aluminum oxide (especially hydrophobic ones are preferred); anti-caking agents; and conductivity-imparting agents such as carbon black, zinc oxide, antimony oxide and tin oxide. . Further, a small amount of white fine particles and black fine particles having a polarity opposite to that of the toner may be used as a developability improver.

  The resin fine particles, inorganic fine powder or hydrophobic inorganic fine powder mixed with the toner is preferably used in an amount of 0.01 to 5 parts by mass (preferably 0.01 to 3 parts by mass) with respect to 100 parts by mass of the toner.

  The toner of the present invention preferably exhibits a sufficient effect when the weight average particle diameter is 2.5 to 10.0 μm, preferably 5.0 to 9.0 μm, more preferably 6.0 to 8.0 μm. And preferred.

  The weight average particle diameter and particle size distribution of the toner are determined using a Coulter counter method. For example, a Coulter Multisizer (manufactured by Coulter Inc.) can be used. As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the volume and number of toner particles of 2.00 μm or more are measured using the 100 μm aperture as the aperture by the measuring device. Volume distribution and number distribution are calculated. Then, the weight-based weight average particle diameter (D4) obtained from the volume distribution according to the present invention is calculated. As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Use 13 channels less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm.

  In order to produce the toner according to the present invention, the above-described toner constituent materials are sufficiently mixed by a ball mill or other mixer, and then kneaded well using a heat kneader such as a hot roll, a kneader or an extruder, and cooled. A method in which after the solidification and coarse pulverization, fine pulverization and classification, and then surface modification of the toner particles using a surface modification device is preferable. Furthermore, the toner according to the present invention can be produced by sufficiently mixing the desired additives with a mixer such as a Henschel mixer, if necessary.

  For example, as a mixer, Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (Hosokawa Micron Co., Ltd.); Spiral pin mixer (Made by Taiheiyo Kiko Co., Ltd.); Ladige mixer (made by Matsubo Co., Ltd.) can be mentioned, and examples of the pulverizer include counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Co.); IDS type mill, PJM jet crusher (Japan New) Cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); Urmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet Oh Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo mill (Turbo Kogyo Co., Ltd.); Super Rotor (Nisshin Engineer) Made ring Co., Ltd.) and the like. Classifiers include: Classy, Micron Classifier, Spedick Classifier (manufactured by Seishin Enterprise); Turbo Classifier (manufactured by Nisshin Engineering); Micron Separator, Turbo Flex (ATP), TSP Separator (manufactured by Hosokawa Micron) An elbow jet (manufactured by Nippon Steel & Mining Co., Ltd.), a dispersion separator (manufactured by Nippon Pneumatic Industrial Co., Ltd.); As a sieving device used to screen coarse particles, Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Deoksugaku Kojo Co., Ltd.); Vibrasonic System (Dalton Co., Ltd.); Soniclean (Shinto) (Industry company); Turbo screener (Turbo industry company); Micro shifter (Ogino industry company); Circular vibration sieve, etc.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

  The magnetic material used in the present invention will be described.

<Manufacture example 1 of a magnetic body>
Sodium silicate is added to the ferrous sulfate aqueous solution so that the Si element content is 0.62% by mass based on the magnetic substance, and the zinc element content is 0.6 based on the magnetic substance. After adding zinc sulfate so that it might become%, the caustic soda solution of 1.0-1.1 equivalent with respect to iron ion was mixed, and the aqueous solution containing ferrous hydroxide was prepared.

Next, air was passed through a ferrous salt aqueous solution containing Fe (OH) ₂ at a temperature of 90 ° C. to carry out an oxidation reaction, thereby producing magnetic particles containing Si element and Zn element.

Further, to this suspension, 1.05 equivalent of sodium hydroxide aqueous solution in which sodium silicate 0.1% (converted to Si element based on the magnetic substance) was dissolved was added to the remaining Fe ²⁺ , and the temperature was further changed to 90. While heating at 0 ° C., magnetic particles containing Si element were generated by oxidation reaction.

  Next, aluminum sulfate is added, the pH is adjusted in the range of 6 to 8, the surface treatment of the magnetic material is performed, and the produced magnetic particles are washed, filtered and dried by a conventional method, and then the agglomerated magnetism. The body particles were crushed (consolidated), and a magnetic body 1 having the characteristics shown in Table 1 was obtained. The average particle size of the magnetic body 1 was 0.18 μm.

<Manufacture example 2 of a magnetic body>
Similarly to Production Example 1, the magnetic substance 2 having physical properties shown in Table 1 was obtained by changing the amounts of Si element, Al element, and Zn element.

<Manufacture example 3 of a magnetic body>
Similar to Production Example 1, the amount of Si element, the amount of Al element, and the amount of Zn element were changed, and copper sulfate was added so that Cu was 0.17% by mass based on the magnetic substance, and the magnetic properties shown in Table 1 were obtained. Body 3 was obtained.

<Magnetic Material Production Example 4>
Similarly to Production Example 1, the magnetic substance 4 having physical properties shown in Table 1 was obtained by changing the amounts of Si element, Al element, and Zn element.

<Magnetic substance production example 5>
As in Production Example 1, the amount of Si element, the amount of Al element, and the amount of Zn element were changed, and copper sulfate was added so that Cu was 0.22% by mass based on the magnetic substance. Body 5 was obtained.

<Magnetic Material Production Example 6>
As in Production Example 1, the amount of Si element, the amount of Al element, and the amount of Zn element were changed, and manganese nitrate was further added so that Mn was 0.45% by mass based on the magnetic substance. Body 6 was obtained.

The wax used in the present invention is as follows.
Alcohol-modified paraffin wax: melting point 90 ° C
Polyethylene wax: melting point 120 ° C

[Preparation of Toner 1]
Binder resin: (Styrene-n-butyl acrylate-methacrylic acid copolymer) 100 parts by mass Magnetic substance 1: 95 parts by mass Negative charge control agent: (Iron azo compound, manufactured by Hodogaya Chemical Co., Ltd .: T-77) 2 Part by mass wax: (alcohol-modified paraffin wax) 4 parts by mass The above mixture was premixed with a Henschel mixer, then melt-kneaded with a twin-screw extruder heated to 140 ° C. according to Table 2, and the cooled kneaded product was hammer milled. The toner was coarsely pulverized to obtain a coarsely pulverized toner. The obtained coarsely pulverized product was coated with a mechanical pulverizer turbo mill (manufactured by Turbo Kogyo Co., Ltd .; coated with chromium alloy plating containing chromium carbide on the rotor and stator surfaces (plating thickness 150 μm, surface hardness HV1050)). Then, the finely pulverized product and the finely pulverized product were classified and removed at the same time using a multi-division classifier (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect. The weight average particle diameter (D ₄ ) measured by the Coulter counter method of the obtained raw toner particles is 6.6 μm, and the cumulative value of the particle size distribution based on the number of toner particles less than 4 μm is 25.3 number%. there were.

The raw toner particles were subjected to surface modification and fine powder removal using a surface modification apparatus shown in FIG. At this time, in this example, 16 square disks coated with chromium alloy plating containing chromium carbide were placed on the upper part of the dispersion rotor, the distance between the guide ring and the upper square disk of the dispersion rotor was 60 mm, and the dispersion rotor The distance between the liner and the liner was 4 mm. Further, the rotational peripheral speed of the dispersion rotor was 140 m / sec, and the blower air volume was 30 m ³ / min. Moreover, the input amount of the finely pulverized product was 300 kg, and the cycle time was 45 sec. The temperature of the refrigerant passed through the jacket was −15 ° C., and the cold air temperature T1 was −20 ° C. Furthermore, the particle ratio of 0.6 μm or more and less than 3 μm was set to a desired value by controlling the rotation speed of the classification rotor. Through the above-described steps, negative chargeability in which the cumulative value of the number-based particle size distribution of toner particles having a weight average particle diameter (D ₄ ) of 6.8 μm and less than 4 μm measured by the Coulter counter method is 18.1% by number. Toner particles 1 were obtained.

  100 parts by weight of the toner particles and 1.2 parts by weight of hydrophobic silica fine powder treated with hexamethyldisilazane and then treated with dimethyl silicone oil were mixed with a Henschel mixer to prepare negatively charged toner 1. .

  The physical properties of toner particles 1 measured by FPIA2100 (particle ratio of 0.6 μm or more and less than 3 μm), the physical properties measured by FPIA2100 of toner 1 (circularity), and the absorbance of the magnetic substance eluted by the hydrochloric acid-surfactant solution. Table 3 shows.

[Preparation of Toners 2 to 10]
The magnetic material and wax to be used are changed as shown in Table 2, the kneading conditions of the thermal kneader are changed as shown in Table 2, the fine grinding conditions of the turbo mill are changed, and the classification conditions in the multi-division classifier are changed. Further, toners 2 to 10 were obtained in the same manner as toner 1 except that the conditions of the surface modifying apparatus were as shown in Table 2. Physical properties of toner particles 2 to 10 measured with FPIA 2100 (particle ratio of 0.6 μm or more and less than 3 μm), physical properties measured with FPIA 2100 of toner 2 to 10 (circularity), magnetic properties eluted with hydrochloric acid-surfactant solution Table 3 shows the absorbance of the body.

[Preparation of Toner 11]
The magnetic material and wax to be used are changed as shown in Table 2, the kneading conditions of the thermal kneader are changed as shown in Table 2, the fine grinding conditions of the turbo mill are changed, and the classification conditions in the multi-division classifier are changed. Further, a toner 11 was obtained in the same manner as the toner 1 except that the surface modification by the surface modification apparatus was not performed. The physical properties of toner particles 11 measured with FPIA2100 (particle ratio of 0.6 μm or more and less than 3 μm), the physical properties of toner 11 measured with FPIA2100 (circularity), and the absorbance of the magnetic substance eluted by the hydrochloric acid-surfactant solution. Table 3 shows.

[Preparation of Toner 12]
The magnetic material and wax to be used are changed as shown in Table 2, and the kneading conditions of the thermal kneader are changed as shown in Table 2. A multi-division classifier using a jet airflow type pulverizer without using a mechanical pulverizer The toner 12 was obtained in the same manner as the toner 1 except that the classification conditions were changed and the conditions of the surface modification apparatus were as shown in Table 2. The physical properties of toner particles 12 measured with FPIA2100 (particle ratio of 0.6 μm or more and less than 3 μm), the physical properties of toner 12 measured with FPIA2100 (circularity), and the absorbance of the magnetic substance eluted by the hydrochloric acid-surfactant solution. Table 3 shows.

[Preparation of Toner 13]
The magnetic material and wax to be used are changed as shown in Table 2, and the kneading conditions of the thermal kneader are changed as shown in Table 2. A multi-division classifier using a jet airflow type pulverizer without using a mechanical pulverizer The toner 13 was obtained in the same manner as the toner 1 except that the classification conditions were changed and the surface modification by the surface modification device was not performed. The physical properties of the toner particles 13 measured by FPIA2100 (particle ratio of 0.6 μm or more and less than 3 μm), the physical properties of the toner 13 measured by FPIA2100 (circularity), and the absorbance of the magnetic substance eluted by the hydrochloric acid-surfactant solution. Table 3 shows.

<Examples 1-4, Reference Examples 5-8 , Comparative Examples 1-5>
Next, the prepared toner was used for evaluation by the following method. The evaluation results are shown in Table 4.

  The following evaluation was performed using a laser beam printer Laser Jet 4300n manufactured by Hewlett-Packard.

(1) Toner consumption 18,000 sheets of image printing test on plain paper for copying machines (A4 size: 75 g / m ² ) with an image with a printing ratio of 4% at room temperature and humidity (23 ° C, 50% RH) Before and after the measurement, the amount of toner in the toner container was measured, and the toner consumption per image was measured.

(2) Dot reproducibility The checker pattern shown in FIG. 3 was printed in a normal temperature / humidity environment (23 ° C., 50% RH), and the dot reproducibility was evaluated based on the following evaluation criteria.
A: Very good (less than 2 defects / 100)
B: Good (3-5 defects / 100 defects)
C: Normal (6-10 defects / 100 defects)
D: Bad (11 or more defects / 100)

(3) Blotch The blotch was evaluated from the toner coat state on the developing sleeve during printing and the printed image in the durability under a low temperature and low humidity environment (15 ° C., 10% RH).
A No blotch is seen on the developing sleeve.
B Although slightly seen on the developing sleeve, the effect does not appear on the image.
C It is seen on the developing sleeve and the effect appears faintly on the image.
D Blotches are seen on the developing sleeve, and the effect appears remarkably on the image.

(4) Image flow After 2,500 consecutive images are printed out in an environment of high temperature and high humidity (32.5 ° C, 80% RH) with an image area ratio of about 3%, the image flow after 2,500 images It was evaluated according to the degree. In this evaluation, paper (using 32.5 ° C., 80% RH and 10% moisture absorption) using talc, which is apt to cause image flow, as a filler was used as an evaluation paper. The moisture absorption of the paper was measured using MOISTREX MX 5000 manufactured by Infrared Engineering. Evaluation was performed according to the following criteria.
A: No image flow occurs.
B: Intermediate level between A and C.
C: Although an image stream has occurred, it is possible to determine what character is.
D: Intermediate level between C and E.
E: An image flow occurs and characters cannot be identified.

(5) Drum fusion After printing out 2,500 sheets of images with an image area ratio of about 3% in a high temperature and high humidity environment (32.5 ° C., 80% RH), A4 size recording paper A solid black image was formed on the entire surface, and the degree of occurrence of white spots on the solid black image was evaluated. Evaluation was performed according to the following criteria.
A: No white spot occurs on A4 size recording paper.
B: Intermediate level between A and B.
C: About 10 white spots are observed on A4 size recording paper.
D: Intermediate level between C and E.
E: 100 or more white spots are seen on A4 size recording paper.

(6) White streaks 2500 images of an image area ratio of about 3% are continuously printed out in a low temperature and low humidity environment (15 ° C., 10% RH), and halftone images after 2500 sheets (1 dot / 2 in the sub-scanning direction) Space) was used to evaluate the level of white streaks.
A: No white streak occurs.
B: White streaks appear but cannot be clearly grasped with the naked eye.
C: Many white stripes can be clearly recognized with the naked eye.

(7) Trailing An image pattern consisting of only horizontal lines with an image area ratio of about 3%. After printing out 6000 sheets continuously in a high-temperature and high-humidity environment (30 ° C, 80% RH), the same horizontal line is being developed. The tailing state of the character part on the electrostatic charge image carrier after development was visually determined according to the following criteria.
A: No tailing has occurred.
B: Good image with slight tailing.
C: Although there is tailing, there is no problem in practical use.
D: An image having a bad tail and not practically preferable.

(8) Image density and fog Print speed of 2 sheets / 10 seconds under low temperature and low humidity environment (15 ° C, 10% RH) and high temperature and high humidity environment (32.5 ° C, 80% RH) 9000 images were printed on a copier plain paper (A4 size: 75 g / m ² ) with a printing ratio of 3%, and left for a day to re-test 9000 sheets, for a total of 18000 images. It was. The results are shown in Table 4.

  For the image density, a “Macbeth reflection densitometer” (manufactured by Macbeth) was used to measure a relative density with respect to a printout image of a white background portion having an original density of 0.00.

  The fog was calculated from a comparison between the whiteness of the transfer paper measured by a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness of the transfer paper after printing solid white.

It is a schematic sectional drawing of the surface modification apparatus of an example used in the surface modification process of this invention. It is the schematic which shows an example of the top view of the dispersion | distribution rotor shown in FIG. It is explanatory drawing of the checker pattern used for dot reproducibility evaluation.

Explanation of symbols

31 Classification rotor 32 Fine powder recovery 33 Raw material supply port 34 Liner 35 Cold air introduction port 36 Dispersion rotor 37 Product discharge port 38 Discharge valve 39 Guide ring 40 Square disk 41 First space 42 Second space

Claims (2)

A magnetic one-component toner having toner particles containing at least a binder resin and a magnetic material,
The magnetic material contains 0.3 to 0.9% by mass of Si element based on the magnetic material, and is further selected from the group consisting of Mn, Zn, Cu, and Al as metal elements other than iron The total amount of the other metal elements is 0.4 to 1.2% by mass based on the magnetic material,
The magnetic one-component toner of the flow type particle image analyzer average circularity of the circle equivalent diameter 400μm or less of the magnetic one-component toner or 3μm measured by is less than 0.930 or 0.970,
The magnetic one-component toner 40mg dispersed in an aqueous surfactant solution 5ml, yet 6mol / l extraction solution surface magnetic of the magnetic one-component toner adding hydrochloric acid 5ml of 30 minutes, the absorption 340nm derived from a magnetic substance The surface absorbance is 2.55 to 3.10 and is surface-modified by a surface modification device that performs surface modification and fine powder removal.
The surface treatment apparatus includes a dispersion rotor for performing a surface modification treatment using a mechanical impact force, a liner disposed with a predetermined gap around the outer periphery of the dispersion rotor, and a surface-modified raw material. Having at least a classification rotor for classifying to a predetermined particle size,
In the number-based particle size distribution of toner particles having an equivalent circle diameter of 0.6 μm or more and 400 μm or less measured by the flow type particle image measuring apparatus of the toner particles, the ratio of toner particles of 0.6 μm or more and less than 3 μm is 0% by number or more Magnetic one-component toner characterized by being less than 20% by number. The magnetic one-component toner according to claim 1, wherein the toner particles contain a wax having polarity.

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