JP2007065245A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner that can obtain fine images of high resolution, regardless of the environments over a long time, in a non-magnetic one-component contact developing system. <P>SOLUTION: This positive electrostatic charging non-magnetic toner has at least positive electrostatic charging non-magnetic toner particles containing at least a binder resin and a coloring agent, and inorganic powder. This inorganic powder is fine magnetic oxide powder that is a crystal system and has a peak at 42.9 deg for the Bragg angle (2θ±0.2 deg) in the CuKα characteristic X-ray diffraction. Further, the half width for the X-ray diffraction peak is 0.40 deg or less for the relation Bragg angle (2θ±0.2 deg)=42.9 deg. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  Conventionally, many methods are known as electrophotographic methods. Generally, a photoconductive substance is used to form an electric latent image on an image carrier (photosensitive member) by various means, and then, The latent image is developed with toner to become a visible image, and if necessary, the toner image is transferred onto a transfer material such as paper, and then the toner image is fixed on the transfer material by heat / pressure to obtain a copy. Is.

  Equipment using electrophotography is applied to devices such as printers and fax machines in addition to conventional copying machines. Especially for printers and fax machines, the electrophotographic process equipment needs to be small, and in order to facilitate maintenance, the toner unit centered on the developing device and the drum unit centered on the electrostatic latent image carrier can be divided into two units. In addition, a process cartridge in which they are integrated has been increasingly used.

  As a developing method used for these process cartridges, there are many one-component developing methods advantageous for downsizing. The one-component developing method uses one-component toner, and the toner is caused by friction between a layer thickness regulating member (hereinafter also referred to as “blade”) and toner particles, and friction between the toner carrier (hereinafter also referred to as “developing roller”) and toner. At the same time as applying electric charge to the particles, it is applied thinly on the developing roller, and the toner is transported to the developing area where the developing roller and the electrostatic latent image carrier face each other, and the electrostatic latent image on the electrostatic latent image carrier is developed. And visualized as a toner image.

  In this one-component development system, a contact development method is also widely used in which development is performed by bringing an electrostatic latent image carrier and a developing roller into direct or indirect contact with each other and bringing a toner layer into contact with the electrostatic latent image carrier. . The contact development method is a development method excellent in fine line reproducibility, image density uniformity and the like, and is preferable as a means for achieving high image quality.

  On the other hand, in the electrophotographic industry, the image resolution of printers and the like has been increased to 1200, 2400 dpi. Accordingly, the development method of the printer apparatus is also required to have higher definition. Also, copying machines are becoming more sophisticated and digitized, and as with printers, higher speed, higher resolution, and higher definition are required. Further, in recent years, non-magnetic toner is frequently used with rapid colorization.

  However, the non-magnetic one-component development method may have inferior charge imparting property to the toner as compared with the two-component development method using a mixture of carrier and toner. This is because the two-component development method has a large surface area of the carrier, which is a charge imparting member for the toner, and therefore the friction frequency with the toner is large, and a stable charge can be imparted to the toner. This is because, in the developing method, the toner regulating member, which is a charge imparting member, and the surface of the toner carrier are small, and there may be toner that is not sufficiently rubbed with these members. For this reason, problems such as defective image density, reverse polarity to the desired charge, that is, reversal toner, and fogging occur particularly in a high humidity environment.

  Further, non-magnetic one-component development does not use a magnetic carrier, but gives a triboelectric charge to the toner to form a toner layer having a uniform thickness, and a toner layer thickness that has elasticity and contacts the developing roller. At least a regulating blade is required. The non-magnetic one-component toner obtains a frictional charge by friction with the developing roller and the regulating blade, and the layer thickness is regulated by the regulating blade. For this reason, particularly in the one-component development, since the layer thickness regulating blade and the developing roller are exposed to stress, the toner aggregate adheres and grows on the toner surface side of the blade by repeated use over a long period of time, and the aggregate becomes the toner. Image formation such as image white streaks occurs due to the formation of a streaky toner layer on the developing roller starting from the aggregate.

  Further, in the case of the contact development method in which the developing roller is in contact with the photoconductor, the mechanical stress is more applied to the toner, so that agglomeration is likely to occur, and not only image defects such as white stripes but also toner fill on the photoconductor. Ming tends to occur. Further, the surface of the developing roller is easily contaminated with the toner component due to repeated use over a long period of time, and the toner surface side of the toner layer thickness regulating blade is also adhered to the toner as described above. Insufficient fog is likely to occur. These problems are prominent in high-speed development systems.

  As described above, in order to stably obtain high-resolution and high-definition images over a long period of time regardless of the environment, it has not only stable charging ability but also strong performance against mechanical stress. Toner is required.

  Conventionally, in order to cope with such a problem, efforts have been made to solve the problem by countermeasures from the toner side, but the current situation is that no fundamental countermeasure has been taken.

  For example, Patent Document 1 proposes to increase the positive chargeability by adding an amino group to the binder resin, and Patent Documents 2 and 3 and the like add charge control agent or charge control resin to the toner. Although improvement is being attempted, the stress resistance of the toner is insufficient. In Patent Documents 4 to 6, silica fine powder is added to the toner. However, in the case of a silica-based fine powder generally used, the effect of improving the toner fluidity is particularly excellent, but sufficient positive chargeability cannot be obtained due to the strong negative polarity. Even if positive chargeability is imparted by treatment with a nitrogen-containing compound or the like, sufficient charge cannot be obtained by the non-magnetic one-component contact development method. Patent Document 7 proposes to add two types of inorganic fine powder, silica and titanium oxide, to the toner, but it is insufficient in terms of both charging stability and mechanical stress resistance. Patent Documents 8 to 10 propose adding magnesium oxide fine powder to toner particles, but there is not enough discussion on the optimization of magnesium oxide fine powder corresponding to the physical properties of toner particles, and there is room for improvement. There is.

JP 2003-255603 A Japanese Patent Laid-Open No. 2004-302008 JP 2003-316082 A JP-A-11-160907 JP-A-11-143111 JP 2004-258265 A JP 2002-372800 A JP 04-083259 A Japanese Patent Laid-Open No. 04-142560 Japanese Patent Laid-Open No. 04-317069

  An object of the present invention is to provide a toner that solves the above problems. That is, an object of the present invention is to provide a toner capable of stably obtaining a high-resolution, high-definition image for a long period of time regardless of the environment in the non-magnetic one-component contact development system.

  The present invention relates to a positively chargeable nonmagnetic one-component toner having at least a positively chargeable nonmagnetic toner particle containing at least a binder resin and a colorant and an inorganic fine powder, wherein the inorganic fine powder is a magnesium oxide fine powder, The magnesium oxide fine powder is a crystal system having a peak at 42.9 deg of the Bragg angle (2θ ± 0.2 deg) in CuKα characteristic X-ray diffraction, and the Bragg angle (2θ ± 0.2 deg) = 42. The half width of the X-ray diffraction peak at 9 deg is 0.40 deg or less.

  Moreover, it is preferable that the free rate of this magnesium oxide fine powder exists in the range of 0.1-5.0%.

  Moreover, the volume average particle diameter (Dv) of the magnesium oxide fine powder is 0.1 to 2.0 μm, and the cumulative volume distribution of the volume average particle diameter (Dv) equal to or less than ½ times the volume distribution is 10% by volume. In the following, it is preferable that the cumulative value of the volume distribution more than twice the volume average particle diameter (Dv) is a particle size distribution of 10% by volume or less.

  Moreover, it is preferable that the isoelectric point of this magnesium oxide fine powder is 8-14.

Moreover, it is preferable that the specific surface area of this magnesium oxide fine powder is 1.0-15.0 m < ² > / g.

  Moreover, it is preferable that MgO content in this magnesium oxide fine powder is 98.0 mass% or more.

  According to the present invention, the positively charged nonmagnetic toner particles have a crystal system having a peak at 42.9 deg of the Bragg angle (2θ ± 0.2 deg) in CuKα characteristic X-ray diffraction, and the Bragg angle (2θ By using magnesium oxide fine powder having an X-ray diffraction peak half width of 0.40 deg or less at ± 0.2 deg) = 42.9 deg, image defects such as white streaks and fogging in the non-magnetic one-component contact development method It is possible to stably obtain a high resolution, high definition image without any problem over a long period of time regardless of the environment.

  As a result of studying the constituent materials used in the toner, the present inventors have controlled the relationship between the positively chargeable nonmagnetic toner particles containing at least a binder resin and a colorant and the inorganic fine powder. In the magnetic one-component contact development system, it has been found that a high resolution and high definition image free from image defects such as white stripes and fogging can be stably obtained over a long period of time regardless of the environment.

  That is, the toner of the present invention is a positively chargeable nonmagnetic one-component toner having at least a positively chargeable nonmagnetic toner particle containing at least a binder resin and a colorant, and an inorganic fine powder. The magnesium oxide fine powder is a crystal system having a peak at 42.9 deg of the Bragg angle (2θ ± 0.2 deg) in CuKα characteristic X-ray diffraction, and the Bragg angle (2θ ± 0.2 deg). ) = 42.9 deg. The half width of the X-ray diffraction peak is 0.40 deg or less.

  As a result of examining the inorganic fine powder to be added to the positively chargeable nonmagnetic toner particles containing at least a binder resin and a colorant, the present inventors have found that the electronegativity is small among the inorganic fine powders, that is, the positive chargeability is low. It has been found that by adding a strong magnesium oxide fine powder, a sufficient charge can be obtained without depending on the environment even in a non-magnetic one-component contact development method with little chance of friction. As a result, it was possible to obtain a good image quality density and stably obtain a clear image without inversion fog.

  In addition, by adding magnesium oxide fine powder with positive chargeability almost equivalent to toner particles whose positive chargeability is improved by using a binder resin or charge control agent, the toner surface is uniformly charged and charged. It has been clarified that an effect of alleviating the electrostatic cohesive force between the toners caused by the non-uniformity of the toner can be obtained. Furthermore, the present inventors have found that since the magnesium oxide has a stable crystal structure, the structure does not change even in an environment in which mechanical stress is strong and does not change. Therefore, it is possible to stably obtain the characteristics peculiar to the above-mentioned magnesium oxide fine powder, and to stably exhibit an appropriate spacer effect for a long time between toner particles, and to reduce cohesiveness due to mechanical stress. I found it possible.

  As a result, even in an environment where a lot of mechanical stress is applied to the toner, such as between the layer thickness regulating blade and the developing roller or between the contact between the photosensitive member and the developing roller, as in the non-magnetic one-component contact developing method, It has been found that the generation of agglomerates can be suppressed over a long period of time and toner deterioration is less likely to occur due to the effect of reducing the agglomeration force by powder. As a result, even in a high-speed development system, it has become possible to stably obtain a high-resolution and high-definition image without image defects such as white stripes and fogging.

  As described above, by adding magnesium oxide fine powder as inorganic fine powder to positively chargeable nonmagnetic toner particles containing at least a binder resin and a colorant, not only has stable charging ability but also mechanical stress. Therefore, it is possible to obtain a toner having a performance with a low cohesive force between the toners. As a result, in the nonmagnetic one-component contact development method, it has become possible to stably obtain a high-resolution and high-definition image over a long period of time regardless of the environment.

  Furthermore, the present inventors efficiently expressed both the stable positive charging ability, which is a feature of the present invention, and the effect of alleviating the cohesive force between toners, and in order to obtain a stable structure, The inventors have found that it is an essential condition to use magnesium oxide crystals with few crystal lattice defects, that is, high-purity magnesium oxide fine powder. The purity of the magnesium oxide fine powder can be estimated using the half width of the X-ray diffraction peak of the magnesium oxide fine powder.

  The magnesium oxide fine powder in the present invention has a peak due to the (200) plane of the magnesium oxide crystal at 42.9 deg with a Bragg angle (2θ ± 0.2 deg) in X-ray diffraction using CuKα rays. The half width of the X-ray diffraction peak at an angle (2θ ± 0.2 deg) = 42.9 deg is 0.40 deg or less. The peak width at half maximum of the X-ray diffraction is 0.40 deg or less because the crystallinity of the magnesium oxide is high, that is, there is little mixing of different metals, lattice defects, etc., and the singleness of the magnesium oxide crystal is strong. Indicates purity.

  When the X-ray peak half width is larger than 0.40 deg, the crystallinity is poor, that is, the purity of the magnesium oxide crystal is low. In other words, the X-ray diffraction peak appears broad because the crystal lattice is distorted due to mixing of different metals or crystal lattice defects. In the case of such magnesium oxide fine powder, leakage of charge due to different metals is likely to occur, water resistance is weak due to crystal lattice defects, hydration occurs due to moisture absorption, and sufficient positive charging ability and cohesive force in the present invention are achieved. The relaxation effect cannot be obtained. Further, since the shape becomes non-uniform and a stable structure cannot be maintained, the spacer effect between the toner particles cannot be sufficiently obtained, and it becomes weak against mechanical stress. Furthermore, it becomes difficult to control physical properties such as broad particle size distribution.

  The X-ray diffraction measurement in the present invention is performed under the following conditions using CuKα rays.

[Sample adjustment]
1) Add 200 ml of THF (tetrahydroxyfuran) to 3 g of toner in a 500 ml beaker.
2) Disperse with an ultrasonic wave for 3 minutes to release the external additive.
3) Separate the THF supernatant solution containing the liberated external additive.
4) Add 200 ml of THF again to the toner, and repeat steps 2) and 3) (about 3 times).
5) Repeat steps 1) to 4) until the required amount of sample is obtained.
6) The separated THF supernatant solution was vacuum filtered through a 2 μm membrane filter to recover the solid content, and an external additive sample was obtained.

[X-ray diffraction measurement conditions]
Measuring instrument used: Rigaku Corporation / Horizontal Sample X-ray Diffractometer (RINT TTR II)
Tube: Cu
Parallel beam optical system voltage: 50 kV
Current: 300mA
Starting angle: 30 °
End angle: 50 °
Sampling width: 0.02 °
Scan speed: 4.00 ° / min
Divergent slit: Open divergence longitudinal slit: 10 mm
Scattering slit: Open light receiving slit: 1.0 mm

  Assignment of the obtained X-ray diffraction peak and calculation of the half-width were performed using Rigaku analysis software “Jade6”.

A shear scan TS-12 (manufactured by Sci-Tec) was used for evaluating the cohesion between the toners. Share scan is Prof. Virendra M.M. The measurement is performed according to the principle of the Morcoulomb model described in “Characterizing Powder Flowability (2002.1.24)” described by Puri. Specifically, the measurement was performed in a room temperature environment (23 to 28 ° C., 40 to 70%) using a linear shear cell (diameter 80 mm, capacity 140 cm ³ ). Toner is put in this cell, and an arbitrary vertical load is applied to produce a compacted powder layer. (In this invention, the measurement by the share scan is used in that the pressure in this compacted state can be automatically detected and produced without individual differences. preferable.). And the fracture | rupture envelope in each load is obtained, and cohesion force and an internal friction angle are calculated | required.

  It is possible to calculate the uniaxial collapse stress and the maximum consolidation stress at each load from the cohesive force and the internal friction angle. The uniaxial collapse stress and the maximum consolidation stress calculated for each load are plotted (Flow Function Plot). Based on the slope of the plot (straight line), the uniaxial collapse stress at an arbitrary consolidation stress is easily solved by the toner. It was used as an index of

  That is, in order to evaluate the cohesion between the toners in a state where the mechanical stress is strongly applied to the toner as in the non-magnetic one-component contact development method in the present invention, the share that can evaluate the cohesion in the compacted powder layer. Most preferably, scanning is used. In the present invention, the value of the uniaxial collapse stress at the maximum consolidation stress of 8.0 kPa at which the cohesive relaxation effect can be effectively evaluated was used as an index of toner cohesiveness.

  Any fine magnesium oxide powder can be used in the present invention, but the following physical properties are preferred.

  The release rate of the magnesium oxide fine powder from the toner particles in the toner of the present invention is preferably from 0.1 to 5.0%, more preferably from 2.0 to 4.0%, particularly preferably from 2.5 to 3.5. %. When the liberation rate is higher than 5.0%, a large amount of the magnesium oxide fine powder is liberated from the toner, so that the effect of reducing the cohesive force between the toners by the magnesium oxide fine powder cannot be sufficiently obtained. Further, the toner is not preferable because proper charging performance cannot be obtained.

  When the liberation rate is lower than 0.1%, it is indicated that almost no magnesium oxide fine powder is liberated from the toner particles. In such a state, the degree of embedding of the magnesium oxide fine powder in the toner particles is usually normal. It tends to occur when it grows. Even in such a case, the effect of alleviating the cohesive force between the toners by the magnesium oxide fine powder cannot be sufficiently obtained. Further, since the toner easily deteriorates, the density decreases in the second half of the durability.

  The release rate of the magnesium oxide fine powder released from the toner particles is measured by a particle analyzer (PT1000: manufactured by Yokogawa Electric Corporation) and is based on the principle described on pages 65-68 of the Japan Hardcopy 97 papers. Measure. Specifically, the apparatus introduces powders such as toner one by one into the plasma to emit light, and the element of the luminescent material, the number of particles, and the particle size of the particles can be known from the emission spectrum of the powder.

The liberation rate is a value defined by the following equation from the simultaneous emission of carbon (C) atoms, which are constituent elements of the binder resin for toner particles, and emission of Mg atoms in the magnesium oxide fine powder.
Magnesium oxide fine powder release rate (%) = 100 × (number of light emission of Mg atoms only / number of light emission of Mg atoms emitted simultaneously with C atoms + number of light emission of only Mg atoms)

  Here, simultaneous light emission of C atoms and Mg atoms means simultaneous light emission of Mg atoms emitted within 2.6 msec from light emission of C atoms, and light emission of Mg atoms thereafter is light emission of only Mg atoms. . As a specific measurement method, after measuring under the following conditions using PT1000 manufactured by Yokogawa Electric Corporation, the liberation rate is obtained by applying the synchronization of light emission of Mg atoms based on C atoms to the above formula.

<Measurement conditions of PT1000 manufactured by Yokogawa Electric Corporation>
-Number of detected C atoms in one measurement: 500-2500
・ Noise cut level: 1.5 or less ・ Sort time: 20 digits
Gas: O ₂ 0.1%, He gas Analysis wavelength C atom: 247.860 nm
Mg atom: 285.210 nm
Use channel C atom: 1 or 2
Mg atom: 1 or 2

  The release rate of the magnesium oxide fine powder is controlled mechanically to the toner particles by controlling the particle size of the magnesium oxide, the BET specific surface area, etc. within an appropriate range, and also taking into account the interaction with other external additives. It can be controlled to an appropriate range by attaching it.

  As a method for mechanically attaching the magnesium oxide fine powder to the toner particles, a known external addition method can be used. That is, a suitable stirring method for producing the toner of the present invention having the above-described release rate is not particularly limited as long as the magnesium oxide fine powder is mechanically attached to the toner particles. This can be done using a stirrer. Preferably, a Henschel mixer, a homogenizer, or the like is used, and more preferably, a Henschel mixer can be used.

  The magnesium oxide fine powder in the toner of the present invention preferably has a volume average particle diameter (Dv) of 0.1 to 2.0 μm, more preferably 0.9 to 2.0 μm, and particularly preferably 1.0 to 1. The volume distribution cumulative value that is 5 μm and the volume average particle diameter (Dv) is less than or equal to ½ times the diameter is preferably 10% by volume or less, and the volume distribution cumulative value that is more than twice the volume average particle diameter (Dv). Is preferably 10% by volume or less. Magnesium oxide fine powder having a volume average particle size (Dv) smaller than 0.1 μm is disadvantageous in terms of imparting fluidity to the toner particles, and as a result, the cohesiveness of the toner is also deteriorated, and the concentration decreases in the latter half of the durability. . Further, when the volume average particle diameter (Dv) is larger than 2.0 μm, the particle size of the magnesium oxide fine powder is increased, so that it is easy to be released from the toner particles. Unfavorable charge cannot be obtained. Furthermore, the volume distribution cumulative value less than or equal to ½ times the volume average particle diameter (Dv) is more than 10% by volume, and the volume distribution cumulative value more than twice the volume average particle diameter (Dv) is 10 or more. If the amount is more than volume%, the particle size distribution becomes broad and the above-mentioned adverse effects are likely to occur, so that the effect of reducing the cohesiveness of the toner cannot be sufficiently obtained.

  The magnesium oxide fine powder has a volume average particle size (Dv) of 0.1 to 2.0 μm, and a volume distribution cumulative value of ½ times the volume average particle size (Dv) is 10% by volume or less, A general classifier can be used as means for achieving a particle size distribution having a volume distribution cumulative value not less than twice the volume average particle diameter (Dv) of 10 volume%, and is not particularly limited.

  As a measuring device for the particle size distribution of the magnesium oxide fine powder of the present invention, a laser diffraction / scattering particle size distribution measuring device LA-920 (manufactured by HORIBA) was used. As a measurement method, several mg of a sample is put in 200 ml of ion-exchanged water as a dispersion so that the sample concentration is about 80% transmittance. Then, this dispersion is subjected to a dispersion treatment with an ultrasonic disperser for 1 minute, and the relative refractive index of the magnesium oxide fine powder and water is set to 1.32. From the measuring device, the volume-based particle size distribution of the magnesium oxide fine powder is set. The volume average particle diameter (Dv), the volume distribution cumulative value less than or equal to ½ times the volume average particle diameter (Dv), and the volume distribution more than twice the volume average particle diameter (Dv) Cumulative values were obtained.

  The magnesium oxide fine powder used in the present invention may be subjected to a surface treatment with a known treating agent. As treatment agents for hydrophobization treatment, treatment agents such as silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds may be used alone or in combination. And may be processed. However, the isoelectric point of the magnesium oxide fine powder of the present invention is preferably 8 to 14, more preferably 9 to 14, and particularly preferably 12 to 14. When the isoelectric point of the magnesium oxide fine powder is lower than 8, since the positive charging ability of the magnesium oxide fine powder is lowered, the cohesiveness mitigating effect is reduced. In addition, fogging is likely to occur due to non-uniform chargeability of the toner.

  The isoelectric point of the magnesium oxide fine powder is determined from the zeta potential. In the present invention, the zeta potential of the magnesium oxide fine powder was measured using an ultrasonic zeta potential measuring device DT-1200 (manufactured by Dispersion Technology). Using pure water as a dispersion liquid, a 0.5 Vol% aqueous solution of magnesium oxide fine powder was prepared, dispersed for 3 minutes with an ultrasonic disperser (VCX-750 manufactured by Sonic & Materials), and then defoamed for about 10 minutes. Stir to make a dispersion. A graph of the pH change of the zeta potential of this dispersion is drawn using the above apparatus, and the isoelectric point is calculated from the graph. The isoelectric point is the pH value when the zeta potential becomes zero.

The specific surface area of the magnesium oxide fine powder used in the present invention is preferably 1.0 to 15.0 m ² / g, more preferably 1.0 to 7.5 m ² / g.

When the specific surface area is larger than 15.0 m ² / g, the magnesium oxide fine powder is embedded in the toner particles, that is, the toner is easily deteriorated. Furthermore, the amount of moisture absorption increases in a high-humidity environment, charging decreases, and the concentration decreases in the second half of durability. On the other hand, if the specific surface area is smaller than 1.0 m ² / g, sufficient fluidity cannot be obtained for the toner, causing problems such as low density.

  As a method for measuring the BET specific surface area, according to the BET specific surface area method, a specific surface area measuring device Gemini 2375 (Shimadzu Corporation) is used to adsorb nitrogen gas on the sample surface, and the BET specific surface area multipoint method is used to determine the specific surface area. Calculated.

  The content of the magnesium oxide fine powder used in the present invention is preferably 0.01 to 2.0 parts by mass, more preferably 0.05 to 1.5 parts by mass with respect to 100 parts by mass of the toner particles. .

  When the content of the magnesium oxide fine powder is larger than 2.0 parts by mass, the charge balance of the toner is lost, and problems such as a decrease in density and fogging tend to occur. When the content of the magnesium oxide fine powder is smaller than 0.01 parts by mass, the amount of addition becomes small with respect to the toner, and the effect of alleviating the cohesive force due to the magnesium oxide fine powder cannot be obtained sufficiently.

  Further, the MgO content in the magnesium oxide fine powder particles used in the present invention is preferably 98.00% or more, more preferably 99.90% or more. If the MgO content is lower than 98.00%, that is, the purity of MgO is low, the effect of reducing the cohesive force by the magnesium oxide fine powder cannot be sufficiently obtained, which is not preferable. Further, due to the charge leakage of different metals, sufficient positive chargeability cannot be maintained and the reverse fog is deteriorated.

  The MgO content in the magnesium oxide fine powder in the present invention was titrated using an EDTA standard solution according to the EDTA method, and CaO mass% (actual value) was subtracted therefrom to obtain MgO mass%.

  The toner of the present invention preferably has an acid value of 0.5 mgKOH / g to 20.0 mgKOH / g.

  By controlling the acid value of the toner within this range, the affinity between the carboxyl group of the positively charged toner particle surface and the surface of the magnesium oxide fine powder is improved, and the magnesium oxide fine powder is surely present on the toner particle surface. Is possible. As a result, the liberation rate of the magnesium oxide fine powder from the toner particles can be controlled within an optimal range, and the cohesive force relaxation effect between the toners is induced most efficiently. Furthermore, by controlling the acid value range, the positive chargeability of the toner particle surface can be made more uniform. As a result, the positive chargeability of the toner surface becomes more uniform, and even in the non-magnetic one-component contact development system. Stable positive chargeability is obtained, and durability development is excellent.

  When the acid value of the toner is less than 0.5 mgKOH / g, the affinity between the toner particle surface and the magnesium oxide fine powder is decreased, so that the magnesium oxide fine powder is easily detached from the toner particle surface. . As a result, the effect of reducing the cohesive force between the toners cannot be obtained. On the other hand, when the acid value exceeds 20.0 mgKOH / g, the negative chargeability in the toner particles becomes strong, the image density tends to decrease, and the fog tends to increase.

  The nonmagnetic toner particles constituting the toner of the present invention contain at least a binder resin and a colorant. As the binder resin for toner used in the present invention, conventionally known resins can be used, but the types of binder resins in the present invention include styrene resins, styrene copolymer resins, amorphous resins. Polyester resin, crystalline polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyurethane resin, polyamide resin, Examples include furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, and petroleum resin.

  Moreover, it is preferable that the binder resin in this invention has an acid value in the range of 1-100 mgKOH / g. Particularly preferred is a resin having an acid value of 1 to 70 mgKOH / g. If it exceeds 100 mgKOH / g, the triboelectric charge amount under high humidity is insufficient, and if it is less than 1 mgKOH / g, the triboelectric charge rate under low humidity becomes slow.

  Examples of the monomer for adjusting the acid value of the binder resin include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, cinnamic acid, vinyl acetic acid, isocrotonic acid, and angelic acid, and α- β-alkyl derivatives, fumaric acid, maleic acid, citraconic acid, alkenyl succinic acid, itaconic acid, mesaconic acid, dimethyl maleic acid, dimethyl fumaric acid and other unsaturated dicarboxylic acids and monoester derivatives or anhydrides thereof, etc. Such a monomer can be used alone or in combination and copolymerized with other monomers to produce a desired polymer. Among these, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid in order to control the acid value.

  More specifically, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate, monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate Monoesters of α, β-unsaturated dicarboxylic acids such as: monobutyl n-butenyl succinate, monomethyl n-octenyl succinate, monoethyl n-butenylmalonate, monomethyl n-dodecenyl glutarate, monobutyl n-butenyl adipate And monoesters of alkenyldicarboxylic acid such as

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

  In the present invention, the acid value was measured using the following method.

Basic operation conforms to JIS K-0070.
1) Toner 0.5 to 2.0 (g) is precisely weighed to obtain the toner weight W (g).
2) Put the sample in a 300 (ml) beaker, and add 150 (ml) of a mixed solution of toluene / ethanol (4/1) to dissolve.
3) Titrate with a potentiometric titrator using a 0.1N KOH methanol solution (for example, a potentiometric titrator AT-400 (winworkstation) manufactured by Kyoto Electronics Co., Ltd.) and an ABP-410 electric burette. Automatic titration can be used.)
4) The amount of KOH solution used at this time is set to S (ml), and a blank is measured at the same time, and the amount of KOH solution used at this time is set to B (ml).
5) Calculate the acid value according to the following formula. f is a factor of KOH.
Acid value (mgKOH / g) = ((SB) × f × 5.61) / W

  The method for producing the toner particles of the present invention is not particularly limited, and a kneaded product obtained by melt-kneading a toner constituent material such as a binder resin, a colorant, a release agent and, if necessary, a charge control agent, after uniform mixing. After cooling, pulverization and classification are performed, and a so-called pulverization method can be used in which the fluidity modifier is sufficiently mixed using a mixer such as a Henschel mixer to obtain the toner of the present invention.

  Examples of the kneader include: KRC kneader (manufactured by Kurimoto Iron Works); bus co-kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Nippon Steel Works) PCM kneading machine (Ikegai Iron Works); Three roll mill, mixing roll mill, kneader (Inoue Seisakusho); Needex (Mitsui Mining); MS pressure kneader, Nider Ruder (Moriyama Seisakusho) ); Banbury mixer (manufactured by Kobe Steel Co., Ltd.), and as the pulverizer, counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron); IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Industrial Co., Ltd.) ; Cross jet mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (Seishin) Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); turbo mill (manufactured by Turboe Industries); super rotor (manufactured by Nissin Engineering Co., Ltd.), and classifiers include a class seal, a micron classifier, and a pedic class Fire (made by Seishin Enterprise Co., Ltd.); turbo classifier (made by Nissin Engineering Co., Ltd.); micron separator, turboplex (ATP), TSP separator (manufactured by Hosokawa Micron); elbow jet (manufactured by Nittetsu Mining Co., Ltd.), dispersion separator ( NIPPON Pneumatic Co., Ltd.); YM Microcut (manufactured by Yaskawa Corporation). Examples of mixers include Henschel mixer (made by Mitsui Mining); Super mixer (made by Kawata); Ribocorn (made by Okawara Seisakusho); Nauter mixer, turbulizer, cyclomix (made by Hosokawa Micron); Spiral pin Mixer (manufactured by Taiheiyo Kiko Co., Ltd.); Laedige mixer (manufactured by Matsubo Co., Ltd.) can be mentioned. Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona sieve, gyro shifter (Tokuju Kogakusha Co., Ltd.); Vibrasonic system (Dalton); Soniclean (Shinto Kogyo); Turbo screener (Turboe); Micro shifter (Ogino Sangyo); Can be mentioned.

  As another method, toner particles can be produced by a so-called polymerization method such as an emulsion polymerization method or a suspension polymerization method.

For example, in the pulverization method, a binder polymerization method includes a solution polymerization method, an emulsion polymerization method, and a suspension polymerization method.

  Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is performed using a water-soluble polymerization initiator. In this method, the reaction heat can be easily adjusted, and the termination reaction rate is low because the phase in which the polymerization is carried out (the oil phase consisting of the polymer and the monomer) and the aqueous phase are separate, resulting in a high polymerization rate. A product having a high degree of polymerization is obtained. Furthermore, the reason is that the polymerization process is relatively simple, and that the polymerization product is fine particles, so that it can be easily mixed with colorants, charge control agents and other additives in the production of toner. Therefore, there is an advantage as a method for producing a binder resin for toner.

  However, the added polymer is likely to be impure due to the added emulsifier, and an operation such as salting out is necessary to take out the polymer. Suspension polymerization is convenient to avoid this inconvenience.

  In suspension polymerization, it is good to carry out by 100 mass parts or less (preferably 10-90 mass parts) of monomers with respect to 100 mass parts of aqueous solvents. Examples of the dispersant that can be used include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like, and generally 0.05 to 1 part by mass with respect to 100 parts by mass of the aqueous solvent. The polymerization temperature is suitably 50 to 95 ° C., but is appropriately selected depending on the initiator used and the target polymer.

  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 various polymer oxides, etc., a functional group having a polymerization initiating function such as two or more peroxide groups in one molecule. And a polyfunctional polymerization initiator having a peroxide group in one molecule such as diallyl peroxydicarbonate, t-butylperoxymaleic acid, t-butylperoxyallylcarbonate and t-butylperoxyisopropyl fumarate And a polyfunctional polymerization initiator having both a functional group having a polymerization initiating function and a polymerizable unsaturated group.

  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 and 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, and t-butylperoxyallyl carbonate.

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

  Among these crosslinkable monomers, aromatic divinyl compounds (particularly divinylbenzene), divalent groups connected by a chain containing an aromatic group and an ether bond are preferred for use in terms of toner fixing properties and offset resistance. Examples include acrylate compounds.

  As other synthesis methods, a bulk polymerization method and a solution polymerization method can be used. However, in the bulk polymerization method, a low molecular weight polymer can be obtained by polymerizing at a high temperature to increase the termination reaction rate, but there is a problem that the reaction is difficult to control. In that respect, the solution polymerization method can easily obtain a polymer with a desired molecular weight under mild conditions by utilizing the difference in chain transfer of radicals by a solvent and adjusting the amount of initiator and reaction temperature. Is preferable. In particular, a solution polymerization method under a pressurized condition is also preferable in that the amount of the initiator used is minimized and the influence of the remaining initiator is minimized.

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

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

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ、ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）
また（２）式で示されるジオール類；

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)
And diols represented by the formula (2);

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

  Moreover, it is preferable to use together the trihydric or more alcohol component and trivalent or more acid component which work as a crosslinking component.

  Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. Is mentioned.

  Examples of the trivalent or higher polycarboxylic acid component in the present invention include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5, 7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene Carboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, and their anhydrides, lower alkyl esters; formula (3)

（式中、Ｘは炭素数３以上の側鎖を１個以上有する炭素数５〜３０のアルキレン基又はアルケニレン基）
で表わされるテトラカルボン酸等、及びこれらの無水物、低級アルキルエステル等の多価カルボン酸類及びその誘導体が挙げられる。

(Wherein X is an alkylene group or alkenylene group having 5 to 30 carbon atoms having one or more side chains having 3 or more carbon atoms)
And polycarboxylic acids such as anhydrides and lower alkyl esters thereof and derivatives thereof.

  The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol%, preferably 55 to 45 mol%. Moreover, it is preferable that the polyvalent component more than trivalence is 5-60 mol% in all the components.

  The polyester resin can also be obtained by a generally known condensation polymerization. A crystalline polyester having a releasing effect is also used.

  Further, as the polymerizable monomer used when the polymerization method, for example, the toner of the present invention is produced by the suspension polymerization method, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl. Styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate , N-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl Methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic polymerizable monomers such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether Vinyl ether such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol Diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4- (methacryloxy-diethoxy) phenyl) propane, Examples include 2,2′-bis (4- (methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.

  In the present invention, the above monofunctional polymerizable monomers are used alone or in combination of two or more, or the above monofunctional polymerizable monomers and polyfunctional polymerizable monomers are used in combination. . The polyfunctional polymerizable monomer can also be used as a crosslinking agent.

  Further, it is preferable to use a macromonomer together with the monovinyl monomer because the balance between the storage stability and the fixing property at a low temperature becomes good. The macromonomer has a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain, and is an oligomer or polymer having a number average molecular weight of usually 8,000 to 40,000.

  As the polymerization initiator used in the polymerization of the polymerizable monomer described above, an oil-soluble initiator and / or a water-soluble initiator is used. For example, as the oil-soluble initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) Azo compounds such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile; acetylcyclohexylsulfonyl peroxide, diisopropylperoxycarbonate, decanoyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide Oxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butylperoxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumylper Kisaido, t- butyl hydroperoxide, di -t- butyl peroxide, include peroxide initiators such as cumene hydroperoxide.

  Water-soluble initiators include ammonium persulfate, potassium persulfate, 2,2′-azobis (N, N′-dimethyleneisobutyroamidine) hydrochloride, 2,2′-azobis (2-aminodinopropane) hydrochloric acid Salts, sodium azobis (isobutylamidine) hydrochloride, sodium 2,2′-azobisisobutyronitrile sulfonate, ferrous sulfate or hydrogen peroxide. In the present invention, in order to control the degree of polymerization of the polymerizable monomer, a known chain transfer agent, polymerization inhibitor or the like can be further added and used.

  As the crosslinking agent used in the toner particles of the present invention, a compound having two or more polymerizable double bonds is used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinylaniline and divinyl ether And divinyl compounds such as divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups. These can be used alone or as a mixture.

  The toner particles of the present invention contain a colorant in order to impart coloring power. Examples of the organic pigment or dye preferably used in the present invention include the following.

  As the organic pigment or organic dye as the cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, a basic dye lake compound, or the like can be used. Specifically, C.I. I. Pigment blue 1, C.I. I. Pigment blue 7, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. And CI Pigment Blue 66.

  As organic pigments or organic dyes as magenta colorants, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds are used. . Specifically, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment violet 19, C.I. I. Pigment red 23, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 166, C.I. I. Pigment red 169, C.I. I. Pigment red 177, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. And CI Pigment Red 254.

  As the organic pigment or organic dye as the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 62, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 111, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 176, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 191, C.I. I. And CI Pigment Yellow 194.

  As the black colorant, carbon black and the one prepared by using the above yellow / magenta / cyan colorant to be blackened are used.

  These colorants can be used alone or mixed and further used in the form of a solid solution. The colorant used in the toner of the present invention is appropriately selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.

  The addition amount of the colorant is used by adding 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  The toner particles of the present invention preferably contain a charge control agent or a charge control resin in order to maintain positive chargeability. As the charge control agent and the charge control resin, all conventionally used for toner can be used without limitation. As the positive charge control agent, a nigrosine dye, a triphenylmethane dye containing a tertiary amine as a side chain, a quaternary ammonium salt compound, a polyamine resin, an imidazole derivative, or the like can be used. According to the description of JP-A-63-60458, JP-A-3-175456, JP-A-3-243594, JP-A-11-15192, JP-A-2000-172015, etc. as the positive charge control resin. For example, a quaternary ammonium (salt) group-containing copolymer produced by the above method can be used.

  In the present invention, it is preferable to contain the following waxes in order to give the toner releasability.

  The waxes used in the present invention include the following. For example, low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax Or block copolymers thereof; plant waxes such as candelilla wax, carnauba wax, wax wax, jojoba wax; animal waxes such as beeswax, lanolin, spermaceti; mineral systems such as ozokerite, ceresin, petrolactam Waxes; waxes based on aliphatic esters such as montanic acid ester wax and castor wax; pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, Polyfunctional ester compounds such as dipentaerythritol hexa myristate; a such aliphatic ester deoxidized carnauba wax obtained by deoxidizing part or all thereof. Further, saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinal acid; stearyl alcohol Saturated alcohol such as eicosyl alcohol, behenyl alcohol, cannavir alcohol, seryl alcohol, melyl alcohol, or alkyl alcohol having a long chain alkyl group; polyhydric alcohol such as sorbitol; linoleic acid amide, oleic acid amide, lauric acid Aliphatic amides such as acid amides; saturated aliphatic bisamides such as methylene bisstearic acid amide, ethylene biscapric acid amides, ethylene bislauric acid amides, hexamethylene bisstearic acid amides; Unsaturated fatty acid amides such as inamide, hexamethylenebisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, Aromatic bisamides such as N'-distearylisophthalamide; aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metal soap); aliphatic hydrocarbons Wax grafted with a vinyl monomer such as styrene or acrylic acid; Partial esterified product of fatty acid and polyhydric alcohol such as behenic acid monoglyceride; Hydroxyl group obtained by hydrogenating vegetable oil Methyl ester compounds It is.

  A mold release agent can be used 1 type or in combination of 2 or more types.

  In addition, these waxes have a sharp molecular weight distribution using a press sweating method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a melt liquid crystal deposition method, a low molecular weight solid fatty acid, a low molecular weight A solid alcohol, a low molecular weight solid compound, and other impurities are preferably used.

  In the toner of the present invention, silica fine powder is added to improve charging stability, developability, fluidity, and durability. In addition, it is possible to uniformly disperse the fine powder of magnesium oxide in the toner by using silica having a high fluidity imparting ability to the toner particle surface and a smaller primary particle number average particle diameter. It turned out to be. When the magnesium oxide fine powder is not uniformly dispersed, the relaxation effect on the interparticle cohesive force is biased, and the deterioration of the toner with respect to high-speed printing tends to proceed. As a result, a decrease in density in the latter half of the endurance due to a decrease in toner charge amount occurs.

As the silica fine powder, both the so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass or the like can be used. Dry silica is preferred because it has few silanol groups on the surface and inside of the silica fine powder, and few production residues such as Na ₂ O and SO ³⁻ . In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

  In the present invention, the silica is preferably hydrophobized. Hydrophobic treatment of silica prevents deterioration of the chargeability of silica in high-humidity environments and improves the environmental stability of the triboelectric charge amount of toner particles with silica attached to the surface, thereby improving the image density as a toner. The environmental stability of development characteristics such as fogging can be further enhanced. As treatment agents for hydrophobization treatment, treatment agents such as silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds may be used alone or in combination. And may be processed. Of these, treatment with a silane compound having a substituent containing nitrogen and silicone oil is particularly preferred from the standpoint of chargeability.

  However, the silane compound greatly contributes to imparting positive chargeability to silica. When the treatment amount is large, the positive chargeability becomes strong, but the hygroscopicity increases due to the hydrophilicity of the amino group. Therefore, when using a silane compound, it is preferable to treat in combination with silicone oil. The treatment can be performed according to a known method.

  Other external additives may be added to the toner of the present invention as necessary.

  Examples thereof include resin fine particles and inorganic fine particles that function as a charging aid, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a release agent at the time of fixing with a heat roller, a lubricant, an abrasive, and the like.

  For example, examples of the lubricant include polyfluorinated ethylene powder, zinc stearate powder, polyvinylidene fluoride powder, and the like. Among these, polyvinylidene fluoride powder is preferable. Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder.

  These external additives can be sufficiently mixed using a mixer such as a Henschel mixer to obtain the toner of the present invention.

  Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on examples. However, this does not limit the embodiment of the present invention.

[Resin (A-1) Production Example]
Propylene oxide adduct of bisphenol A (average addition mol number: 2.2 mol) 34.0 mol%, ethylene oxide adduct of bisphenol A (average addition mol number: 2.2 mol), 19.5 mol%, isophthalic acid 23. 5 mol%, n-dodecenyl succinic acid 13.5 mol%, trimellitic acid 9.5 mol% and dibutyltin oxide were added in an amount of 0.03 parts by mass to the total acid components, and the mixture was stirred at 22.0 ° C for 6 hours under a nitrogen stream. The polyester resin (A-1) was obtained while reacting.

[Resin (A-2) Production Example]
After completion of the polyester resin A-1 reaction, 5 mass% of silohexamethylene diisocyanate was reacted with respect to the calculated synthetic polymer amount to obtain an isocyanate-modified polyester resin (A-2).

[Resin (A-3) Production Example]
After reacting 51.0 mol% of 1,4 butanediol, 49.0 mol% of fumaric acid and 3.0 g of dibutyltin oxide at 180 ° C. for 4 hours in a nitrogen atmosphere, the temperature was raised to 220 ° C. and reacted for 2 hours. I let you. Furthermore, it was made to react at 9.5 kPa and the polyester resin (A-3) of MW = 1.500,000 was obtained.

[Production example of resin (A-4)]
In a three-necked flask equipped with a stirrer, thermometer, reflux condenser, water pipe and nitrogen gas inlet pipe, 542 parts by mass of 4-methyl-hexahydrophthalic anhydride and 100 parts by mass of bis (β-hydroxyethyl) hexahydroterephthalate Parts, 35 parts by weight of 5-aminohexahydroisophthalic acid dimethyl ester, 275 parts by weight of 2,2-bis (4-hydroxycyclohexyl) -propane, and 170 parts by weight of ethylene glycol were charged. The mixture was stirred while introducing nitrogen gas, and reacted at 230 ° C. for 2.5 hours while removing alcohol generated during the reaction. Next, 7.5 parts by mass of tetrabutoxy titanate is added, the reaction temperature is raised to 250 ° C., and the pressure in the flask is gradually reduced. After 1.0 hour, the pressure is reduced to 5 mmHg or less, and then the reaction is continued for another 5 hours. Resin (A-4) was obtained.

[Production Example of Toner Particles (B-1)]
(Binder resin) Isocyanate-modified polyester resin (A-2) 100 parts by mass (colorant) Carbon black 5 parts by mass (charge control resin) Styrene having a trisubstituted ammonio group represented by the following structural formula (4) in the side chain
-Acrylic resin (MW = 8,000, styrene ratio 70.25 mol)
%, N-butyl acrylate ratio 29.5 mol%, trisubstituted ammonio group
Containing monomer ratio 0.25 mol%) 3 parts by mass (release agent) Low molecular weight polypropylene ("Biscol 550P" manufactured by Sanyo Chemical Co., Ltd.)
1 part by mass These were respectively charged and mixed in a Henschel mixer, melt-kneaded with a twin screw extruder, and cooled with a drum flaker. Next, coarsely pulverized with a hammer mill, then finely pulverized with a jet mill, and classified using an air classifier to obtain toner particles (B-1) having a weight average particle diameter of 7.3 μm.

（式中、Ｒ¹，Ｒ²は、メチル基、Ｒ³はｎ−ブチル基、Ｘ−はモリブデン酸イオンを示す。）

(In the formula, R ¹ and R ² represent a methyl group, R ³ represents an n-butyl group, and X- represents a molybdate ion.)

[Production Example of Toner Particles (B-2)]
After adding 450 parts by mass of 0.1 mol / liter-Na ₃ PO ₄ aqueous solution to 400 parts by mass of ion-exchanged water and heating to 50 ° C., using a TK homomixer (manufactured by Special Machine Industries), 10000 rpm Was stirred. To this was added 68 parts by mass of a 1.0 mol / liter-CaCl ₂ aqueous solution to obtain an aqueous medium containing a calcium phosphate salt.

on the other hand,
(Monomer) Styrene 75 parts by mass n-butyl acrylate 25 parts by mass polymethacrylic acid ester macromonomer (manufactured by Toa Gosei Chemical Co., Ltd., trade name “AA6”)
0.4 parts by mass t-dodecyl mercaptan 1.5 parts by mass Methacrylic acid 5 parts by mass (colorant) Carbon black 7 parts by mass (charge control resin) Quaternary ammonium base-containing copolymer (MW = 50,000, styrene ratio) 90.25 mol%, n-butyl acrylate ratio 9.50 mol%, quaternary ammonium base-containing monomer ratio 0.25 mol%) 5 parts by mass (release agent) dipentaerythritol hexamyristate 10 parts by mass The mixture was heated to 0 ° C., and uniformly dissolved and dispersed at 9000 rpm using a TK homomixer (manufactured by Special Machine Industries). In this, 3 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved as a polymerization initiator to prepare a polymerizable monomer composition.

  The polymerizable monomer composition was put into the aqueous medium and stirred at 8000 rpm with a TK homomixer at 50 ° C. in a nitrogen atmosphere to granulate the polymerizable monomer composition. Then, while stirring with a paddle stirring blade, the temperature was raised to 60 ° C. in 2 hours and reacted for 5 hours. Then, it heated up at 80 degreeC with the temperature increase rate of 40 degreeC / hr, and was made to react for 5 hours. After completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure, and after cooling, hydrochloric acid was added and stirred for 6 hours. Thereafter, filtration, washing with ion exchange water, and drying were performed to obtain black toner particles (B-2). The black toner particles (B-2) had a weight average particle diameter of 6.8 μm.

[Production Example of Toner Particles (B-3)]
(Binder resin) Polyester resin (A-1) 100 parts by mass (colorant) Carbon black 6.5 parts by mass (charge control agent) Quaternary ammonium salt “TP-415” (manufactured by Hodogaya Chemical Co., Ltd.)
0.1 parts by weight (release agent) 2 parts by weight of polypropylene wax “NP-105” (Mitsui Chemicals) These were each put into a Henschel mixer, mixed, melt-kneaded with a twin screw extruder, and drum flaker It was cooled with. Next, coarsely pulverized with a hammer mill, then finely pulverized with a jet mill, and classified using an air classifier to obtain toner particles (B-3) having a weight average particle diameter of 7.5 μm.

[Production Example of Toner Particles (B-4)]
80 parts by weight of polyester resin (A-1) as binder resin, 20 parts by weight of polyester resin (A-3), and carnauba wax “Carnauba wax No. 1” (manufactured by Kato Yoko Co., Ltd.) 1.5 A toner particle (B-4) having a weight average particle diameter of 7.5 μm was obtained in the same manner as in the toner particle production example (B-3) except that the part by mass was used.

[Production Example of Toner Particles (B-5)]
Binder resin Polyester resin (A-4) 100 parts by weight Colorant Carbon black 6 parts by weight Release agent Dipentaerythritol hexamyristate 10 parts by weight Each of these is put into a Henschel mixer and mixed, and then melted with a twin screw extruder The mixture was kneaded and cooled with a drum flaker. Next, after coarsely pulverizing with a hammer mill, finely pulverizing with a mechanical pulverizer and classifying with an air classifier, toner particles (B-5) having a weight average particle diameter of 7.1 μm were obtained.

[Production Example of Toner Particles (B-6)]
In the production example of toner particles (B-2), the colorant was changed to a yellow colorant (CI Pigment Yellow 74), and the addition amount was changed to 5 parts by mass. Were used to produce yellow toner particles (B-6) having a weight average particle diameter of 6.6 μm.

[Production Example of Toner Particles (B-7)]
In the toner particle (B-2) production example, the colorant was changed to a magenta colorant (CI Pigment Red 122), and the addition amount was changed to 5 parts by mass. Using the method, magenta toner particles (B-7) having a weight average particle diameter of 6.6 μm were produced.

[Production Example of Toner Particles (B-8)]
The above production example (B-2) except that the colorant was changed to a cyan colorant (CI Pigment Blue 15: 3) in the toner particle (B-2) production example and the addition amount thereof was 5 parts by mass. Using the same method, cyan toner particles (B-8) having a weight average particle diameter of 6.5 μm were produced.

  The preparation method of the magnesium oxide fine powder in the present invention is not particularly limited as long as the above requirements are satisfied.

[Production Example of Fine Magnesium Oxide Powder (C-1)]
0.81 equivalent of an alkaline substance is mixed with 1 equivalent of a water-soluble magnesium salt that has been subjected to a purification treatment at 30 ° C. or less, and the reaction product is reacted with the reaction mother liquor under a pressure of about 7.8 MPa for about 4 hours. Magnesium hydroxide was obtained by heating. This magnesium hydroxide was calcined at 1400 ° C. for 4 hours in a cantal furnace. The fired product was pulverized and classified using a pulverizer equipped with an airflow classification mechanism to obtain a magnesium oxide fine powder (C-1). Table 1 shows the physical property values of the obtained magnesium oxide fine powder (C-1).

[Production Example of Fine Magnesium Oxide Powder (C-2)]
Magnesium oxide fine powder (C-2) was prepared in the same manner as in Production Example (C-1) except that the firing time was 2 hours in Production Example (C-1).

[Production Example of Fine Magnesium Oxide Powder (C-3)]
Magnesium oxide fine powder (C-3) was prepared in the same manner as in Production Example (C-1) except that 0.70 equivalent of alkaline substance was mixed with 1 equivalent of water-soluble magnesium salt in Production Example (C-1).

[Production Example of Fine Magnesium Oxide Powder (C-4)]
Magnesium oxide fine powder (C-4) was prepared in the same manner as in Production Example (C-1) except that the firing temperature was 1700 ° C. in Production Example (C-1).

[Production Example of Fine Magnesium Oxide Powder (C-5)]
Magnesium oxide fine powder (C-5) was prepared in the same manner as in Production Example (C-1) except that the firing time in Production Example (C-1) was 6 hours and the firing temperature was 1700 ° C.

[Production Example of Fine Magnesium Oxide Powder (C-6)]
Magnesium oxide fine powder (C-6) was prepared in the same manner as in Production Example (C-1) except that the firing temperature was 1100 ° C. in Production Example (C-1).

[Production Example of Fine Magnesium Oxide Powder (C-7)]
In Production Example (C-1), 0.60 equivalent of alkaline substance is mixed with 1 equivalent of water-soluble magnesium salt, the firing time is 2 hours, and the firing temperature is 900 ° C. The same as in Production Example (C-1) Thus, a magnesium oxide fine powder (C-7) was prepared.

[Magnesium oxide fine powder (C-8)]
As magnesium oxide fine powder (C-8), vapor-phase oxidation magnesia (2000A manufactured by Ube Materials) was used.

[Production Example of Fine Magnesium Oxide Powder (C-9)]
Fine magnesium oxide was used in the same manner as in Production Example (C-1) except that seawater was used as the Mg source, quick lime was used as the alkali source, the firing time was 2 hours in Production Example (C-1), and the firing temperature was 700 ° C. Powder (C-9) was prepared.

[Production Example of Fine Magnesium Oxide Powder (C-10)]
Fine magnesium oxide was used in the same manner as in Production Example (C-1) except that seawater was used as the Mg source, quick lime was used as the alkali source, the firing time was 6 hours in Production Example (C-1), and the firing temperature was 1800 ° C. Powder (C-10) was prepared.

  Table 1 shows the physical properties such as X-ray diffraction peak half-widths of the magnesium oxide fine powders (C-1) to (C-10).

[Example 1]
0.1 parts by mass of magnesium oxide fine powder (C-1) having physical properties shown in Table 1 and silica fine powder (E-1) (manufactured by Hoechst, based on 100 parts by mass of toner particles (B-2) Toner 1 was obtained by mixing 0.5 parts by mass of a product name “HVK2150”) with a Henschel mixer. The toner physical properties are shown in Table 2.

  This toner 1 is a modified non-magnetic one-component developing type printer (manufactured by Brother Kogyo Co., Ltd., trade name “HL1670N” modified to 1.5 times the printing speed) and used in a high temperature and high humidity environment ( 35,000 ° C, 80% RH), normal temperature and humidity (23 ° C, 50% RH), normal temperature and low humidity (23 ° C, 5% RH). Went. The evaluation results are shown in Tables 3, 4, and 5.

[Evaluation methods]
(Image density)
The image density was measured with a Macbeth densitometer (manufactured by Macbeth Co., Ltd.) using an SPI filter. The reflection density was measured after the end of the 15,000-sheet continuous printing test at the initial stage of durability, and a 5 mm square image was measured.

(Cover on paper)
The fog on paper was measured using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku Co., Ltd. after completion of the 15,000-sheet continuous print test. A green filter was used as the filter. The fog value was calculated from the following formula using a solid white image. If the fog on paper is 2.0% or less, a good image is obtained.
Fog (reflectance) (%) = reflectance on standard paper (%) − reflectance of sample non-image area (%)

(Striped image missing in halftone image)
After the completion of the 15,000-sheet continuous print test, all halftone images were printed using plain paper that had been sufficiently conditioned in each test environment. In this image, the number of white stripes having a width of 0.5 mm or less was counted and judged based on the number.
A: No white streak is generated.
B: The number of white stripes is 1 to 3.
C: The number of white stripes is 4 to 7.
D: The number of white stripes is 8-10.
E: The number of white stripes is 11 or more, or white stripes exceeding 0.5 mm in width are generated.

(Filming)
After the 15,000-sheet continuous print test was completed, the drum fusion marks on the sample image were counted in each test environment, and ranked according to the number of drum fusion marks per 10 cm 2 as follows.
A: Less than 1.0 B: 1.0 or more and less than 3.0 C: 3.0 or more and less than 7.0 D: 7.0 or more

(Observation of toner fixing state of toner regulating member)
After the 15,000-sheet continuous print test was completed, the toner regulating member was observed in each test environment.
A: The toner is not fixed at all.
B: The toner is slightly fixed.
C: A small amount of toner is fixed.
D: A large amount of toner is fixed.

[Example 2]
In the formulation shown in Table 2, 0.1 parts by mass of magnesium oxide fine powder (C-2) having physical properties shown in Table 1 and silica fine powder (E-4) (product name “RA200” manufactured by Nippon Aerosil Co., Ltd.) ) Toner 2 was prepared in the same manner as in Example 1 except that 0.6 part by mass was added. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 3]
In the formulation shown in Table 2, 0.1 parts by mass of magnesium oxide fine powder (C-3) having physical properties shown in Table 1 and silica fine powder (E-3) (trade name “HDK H3050VP” manufactured by Clariant Japan) ) Toner 3 was prepared in the same manner as in Example 1 except that 0.3 part by mass was added. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 4]
Implemented except that 0.1 parts by mass of the magnesium oxide fine powder (C-4) having physical properties described in Table 1 and 0.3 part by mass of silica fine powder (E-3) were added according to the formulation shown in Table 2. Toner 4 was prepared in the same manner as in Example 1. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 5]
Toner 5 was prepared in the same manner as in Example 1 except that 0.1 parts by mass of the magnesium oxide fine powder (C-5) having physical properties described in Table 1 was added according to the formulation described in Table 2. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 6]
0.1 parts by mass of magnesium oxide fine powder (C-6) having physical properties described in Table 1 and silica fine powder (E-2) (trade name “HDK2150”, manufactured by Clariant Japan) Toner 6 was produced in the same manner as in Example 1 except that 0.6 part by mass was added. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 7]
Implemented except that 0.02 parts by mass of the magnesium oxide fine powder (C-7) having physical properties described in Table 1 and 0.6 part by mass of silica fine powder (E-4) were added according to the formulation shown in Table 2. Toner 7 was prepared in the same manner as in Example 1. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 8]
Implemented with the formulation shown in Table 2 except that 1.8 parts by mass of magnesium oxide fine powder (C-8) having physical properties shown in Table 1 and 0.6 part by mass of silica fine powder (E-4) were added. Toner 8 was prepared in the same manner as in Example 1. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5.

[Example 9]
Toner particles B-2 and B-6 to 8 obtained in Toner Particle Production Examples 2 and 6 to 8 are each externally added and mixed in the same formulation as in Example 1 to 100 parts by mass to produce each color toner 13. did.

  Using each of these color toners 13 obtained by modifying the printing speed of a commercially available color printer (trade name “FS-C5016” manufactured by Kyocera Mita Co., Ltd.) by 1.5 times to a one-component contact development system, As a result of the same evaluation, all evaluations were good in any environment.

[Comparative Examples 1-4]
Toners 9 to 12 were prepared according to the formulation and external addition conditions described in Table 2. The physical property values thus obtained are shown in Table 2, and the results of the same tests as in Example 1 are shown in Tables 3, 4 and 5. In addition, as the inorganic fine powder in the formulation described in Table 2, in addition to magnesium oxide fine powder (C-9) and (C-10) obtained by the seawater method, titanium oxide fine powder (particle size 0.27 μm) , Isoelectric point 5.0) was used.

Claims (6)

In a positively chargeable nonmagnetic one-component toner having at least a positively chargeable nonmagnetic toner particle containing at least a binder resin and a colorant and an inorganic fine powder,
The inorganic fine powder is a magnesium oxide fine powder, and the magnesium oxide fine powder is a crystal system having a peak at 42.9 deg of Bragg angle (2θ ± 0.2 deg) in CuKα characteristic X-ray diffraction, and A toner characterized in that the half-value width of an X-ray diffraction peak at a Bragg angle (2θ ± 0.2 deg) = 42.9 deg is 0.40 deg or less.   The toner according to claim 1, wherein a release rate of the magnesium oxide fine powder is in a range of 0.1 to 5.0%.   The volume average particle diameter (Dv) of the magnesium oxide fine powder is 0.1 to 2.0 μm, and the volume distribution cumulative value of ½ times the volume average particle diameter (Dv) is 10% by volume or less, 3. The toner according to claim 1, wherein the toner has a volume distribution cumulative value not less than twice the diameter of the volume average particle diameter (Dv) of 10% by volume or less.   The toner according to claim 1, wherein the magnesium oxide fine powder has an isoelectric point of 8 to 14. 5. The toner according to claim 1, wherein the specific surface area of the magnesium oxide fine powder is 1.0 to 15.0 m ² / g.   The toner according to claim 1, wherein the MgO fine powder has a MgO content of 98.00% or more.