JP2012150172A - Toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner capable of obtaining a good image without causing fogging and image unevenness in half tone image, even when used over a long term in high speed printing under a low temperature and low humidity environment.SOLUTION: A toner includes a toner particles containing binder resin and colorant, silica particles (A), and inorganic fine powder. The silica particles (A) have a volume average particle size (Dv) of primary particles of 70 nm or more and 500 nm or less, a variation coefficient of volume particle size distribution of 23% or less, an average fine pore diameter of 5.0 nm or more and 25.0 nm or less, and a total fine pore volume measured in the range of fine pore diameter of a range of 1.7 nm or more and 300.0 nm or less of 0.02 cm/g or more and 1.20 cm/g or less.

Description

  The present invention relates to an electrostatic charge image developing toner used for electrophotographic image formation represented by copying machines and printers.

  As electrophotographic technology used in copying machines, printers, facsimile receivers, etc., the demands from users are becoming more and more demanding year by year as the devices develop. In recent years, there is a strong demand to provide stable image quality that does not depend on the environment because it is possible to print a large number of sheets and the environment used by the expansion of the market has expanded. .

  In order to satisfy the above requirements, a toner having high durability and high image quality is required more than before, and attempts have been made to solve the above problems by improving silica particles used in the toner. .

  Patent Document 1 describes that by adding submicron-sized silica particles to the toner as an external additive, good transferability or developability can be obtained. Patent Document 1 proposes a method in which silica particles produced by a sol-gel method are added to toner particles to reduce the physical adhesion between the toner and the photoreceptor, improve transferability, and achieve high image quality. Has been. In Patent Document 2, high-solubility sol-gel silica particles are externally added to the toner to improve the fluidity, fixing property, cleaning property, and environmental stability of the charge amount, thereby realizing high image quality. A method has been proposed.

  Certainly, such a measure tends to provide good transferability or developability. However, as a result of intensive studies by the present inventors, there is still room for improvement in image problems such as fogging and halftone image unevenness when the above technology is applied to a high-speed and long-life printer in a low-temperature and low-humidity environment. I understood. In order to obtain a stable image independent of the use environment, further improvement of these techniques is necessary.

JP 2002-108001 A JP 2007-99582 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a toner having good durability that is less likely to cause fogging and halftone image unevenness even in high-speed and long-term printing in a low-temperature and low-humidity environment.

The present invention is a toner having toner particles containing a binder resin and a colorant, and silica particles A, wherein the silica particles A have primary particles having a volume average particle diameter (Dv) of 70 nm to 500 nm. Yes, the coefficient of variation in volume particle size distribution is 23% or less, the average pore diameter is 5.0 nm or more and 25.0 nm or less, and the total pore volume measured in the range of pore diameters 1.7 nm or more and 300.0 nm or less There a toner which is characterized in that not more than 0.02 cm ³ / g or more 1.20cm ³ / g.

  According to the present invention, a toner having excellent environmental stability and durability can be obtained. In other words, even in high-speed and long-term printing under low temperature and low humidity, it is possible to provide a toner that is less likely to cause fogging and halftone image unevenness and can provide a good image.

  As a result of intensive studies by the present inventors, it is possible to appropriately control the particle size distribution and pore shape of silica particles, and to use such silica particles in toner, thereby enabling high-speed and long-term printing under low temperature and low humidity. Also, it was found that a toner having good durability can be obtained.

  The silica particle A used in the present invention is a large particle size silica having a volume average particle size (Dv) of 70 nm or more and 500 nm or less. When the volume average particle diameter of the silica particles A is larger than 500 nm, the fluidity of the toner is inhibited and it tends to be easily detached from the toner surface. For this reason, it is impossible to impart stable chargeability and fluidity to the toner over a long period of time. Further, the detached silica particles A may adhere to and contaminate the developer constituting material and the image forming system member, and may have adverse effects such as deterioration of charging characteristics and accompanying fog deterioration. On the other hand, when the volume average particle size is smaller than 70 nm, a sufficient spacer effect cannot be exhibited as the large particle size silica, and transferability and toner surface deterioration may occur. The volume average particle diameter (Dv) of the silica particles A is preferably 80 nm or more and 200 nm or less.

  Silica particles A have a coefficient of variation in volume particle size distribution of 23% or less. When the variation coefficient in the volume particle size distribution of the silica particles A is within the above range, the silica particles A can exhibit the spacer effect more effectively on the toner surface, and the transferability of the toner is improved. Furthermore, a toner having stable charging properties and fluidity over a long period can be obtained. When the coefficient of variation is greater than 23%, even if the volume average particle size (Dv) of the silica particles is within the above range, the variation in the volume particle size distribution of the silica particles is large. Therefore, each silica particle does not function efficiently as a spacer particle, and transferability is not improved. Further, since there is a difference in the chargeability and fluidity imparted to the toner of each silica particle, the charge distribution is widened and the fog and the like are deteriorated. For this reason, it is not possible to obtain a toner having stable chargeability, fluidity and transferability over a long period of time. The coefficient of variation in the volume particle size distribution of the silica particles A is preferably 10% or less.

<Measurement of coefficient of variation in volume average particle size and volume particle size distribution of silica particles A>
The measurement of the variation coefficient in the volume average particle diameter and volume particle size distribution of the silica particles A in the present invention is performed using a zetaizer Nano-ZS (manufactured by Sysmec). The coefficient of variation is obtained by measuring the half width (width) and the volume average particle diameter, and calculating the ratio (%) of the half width to the volume average particle diameter. Sample adjustment and measurement conditions are as follows.

  About 1 mg of silica particles A is added to pure 20 ml, and dispersed for 3 minutes using a homogenizer (manufactured by SMT). In order to reduce the influence due to the aggregation of the silica particles, the volume average particle diameter and the coefficient of variation are measured immediately after dispersion under the following conditions.

〔Measurement condition〕
-Cell: DTS0012-Disposable sizing cuvette
・ Dispersant: Water
-Refractive Index:
material: 1.460
dispersant: 1.330
・ Temperature: 25 ° C
・ Measurement duration:
Number of runs: 5
Runs duration (Seconds): 10
・ Result Calculation: General Purpose
The present invention is characterized in that the pores are in a specific state in the silica particles A having a large particle diameter as described above. That is, the silica particles A used in the present invention have an average pore size of 5.0 nm or more and 25.0 nm or less, and a total pore volume measured in a range of pore diameters of 1.7 nm or more and 300.0 nm or less is 0. 0.02 cm ³ / g or more and 1.20 cm ³ / g or less.

  The present inventors consider the effects of the present invention obtained by using such silica particles A as follows. The surface of the silica particles is contact-charged by rubbing with toner particles or a rubbing member. At this time, if pores are present on the surface of the silica particles, the voids in the pores are not contact-charged. Therefore, on the surface of the silica particles, the chargeability of the silica particles decreases as the proportion of the pores (pore volume) increases. At the same time, since the amount of charge generated by a single contact is reduced, it is considered that the surface of the silica particles approaches a uniform charged state with little charge bias. Thereby, it is considered that the toner of the present invention is suppressed from being overcharged and charged uniformly, particularly in a low temperature and low humidity environment. Moreover, the effect by such a pore has high durability stability, and it is thought that an effect can be maintained in the second half of durability.

  In the present invention, the volume average particle diameter (Dv) and coefficient of variation of the primary particles of the silica particles are appropriately controlled for the pore diameter and pore volume of the silica particles as described above, particularly in a low humidity environment. The charge amount of the silica particles can be appropriately controlled. As a result, by controlling the toner charge amount under low temperature and low humidity to an appropriate value, image defects such as fogging and halftone image unevenness caused by insufficient charging or overcharging of the toner are suppressed, and high durability is obtained. Can do.

  When the average pore diameter of the silica particles is smaller than 5.0 nm, the pores are too small, so that the effect of suppressing overcharge due to voids is reduced. As a result, the charge amount of the silica particles tends to increase, and the toner tends to be overcharged. Such toner is liable to cause image defects when used for a long time in a low temperature and low humidity environment. For example, when such a toner is used in a non-magnetic one-component contact development method, halftone image unevenness is likely to occur. This is considered to be because it is difficult to remove the development residual toner on the toner carrying member by the toner peeling member due to overcharging. As the development residual toner on the toner carrier increases, the total amount of toner regulated by the toner regulating member increases and it becomes difficult to regulate uniformly. This makes it difficult to uniformly charge the toner on the toner carrier. As a result, it is considered that charging unevenness occurs on the toner carrying member, and density unevenness in the halftone image is caused.

  On the other hand, when the average pore diameter of the silica particles is larger than 25.0 nm, the size of the pores is large with respect to the contact area, and the charge amount generated on the surface of the silica particles by one contact becomes non-uniform. For this reason, the surface of the silica particles is likely to be biased, and the charge amount distribution of the toner is deteriorated due to unevenness in the charge amount of the silica particles. As a result, the amount of insufficiently charged toner tends to increase and fogging tends to deteriorate. The average pore diameter of the silica particles A used in the present invention is preferably 15.0 nm or more and 25.0 nm or less.

When the total pore volume of the silica particles is smaller than 0.02 cm ³ / g, the number of pores is small or the pores are shallow, so that the effect of suppressing overcharge by the pores cannot be sufficiently obtained. On the other hand, when the total pore volume is larger than 1.20 cm ³ / g, the silica particles are porous and have low mechanical strength. For this reason, the pores of the silica particles are easily crushed by mechanical stress in the developing machine, and it becomes difficult to maintain good chargeability during long-term use. Silica particles A, the total pore volume measured in the range of less pore diameter 1.7nm or more 300.0nm is preferably 0.05 cm ³ / g or more 0.40 cm ³ / g or less.

<Measurement of average pore diameter and pore volume of silica particles>
The average pore diameter and total pore volume of the silica particles in the present invention are measured by a gas adsorption method in which nitrogen gas is adsorbed on the sample surface using a pore distribution measuring device Tristar 3000 (manufactured by Shimadzu Corporation). The measurement method follows the operation manual issued by Shimadzu Corporation. First, about 0.5 g of a sample is put in a sample tube, and evacuation is performed at 100 ° C. for 24 hours. After evacuation, the sample weight is precisely weighed to obtain a sample. From the obtained sample, the average pore diameter and the total pore volume in the range of not less than 1.7 nm and not more than 300.0 nm can be obtained by the BJH adsorption method using the pore distribution measuring apparatus. As the density value necessary for the measurement, a true density value measured using a dry densitometer Accupic 1330 (manufactured by Shimadzu Corporation) is used.

  As described above, by controlling the existence state of the pores in the silica particles having a large particle size, the chargeability of the silica particles can be appropriately controlled, and the toner using the silica particles can be used at low temperature and low humidity. Even in high-speed and long-term printing, good developability can be maintained.

  The method for hydrophobizing the silica particles A is not particularly limited, and a known method can be used. As a method for hydrophobizing silica particles, there are a method of dry-treating a hydrophobizing agent on silica particles, and a method of wet-treating a hydrophobizing agent on silica particles by immersing in a solvent such as water or an organic compound. Can be mentioned.

  Among these, a dry hydrophobizing method is preferable because it can impart excellent fluidity to the toner while preventing aggregation of silica particles. Examples of the hydrophobizing treatment method by dry method include a method of spraying the hydrophobizing agent while stirring the silica particles, and a method of introducing the hydrophobizing agent vapor into the fluidized bed or the stirring silica particles. .

  Examples of the hydrophobizing agent for silica particles include the following. Chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, t-butyldimethylchlorosilane, vinyltrichlorosilane; tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane , Diphenyldimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, Dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxy Silane, diphenyldiethoxysilane, i-butyltriethoxysilane, decyltriethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyl Dimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ Alkoxysilanes such as-(2-aminoethyl) aminopropylmethyldimethoxysilane; hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisi Silazanes such as zan, hexahexyldisilazane, hexacyclohexyldisilazane, hexaphenyldisilazane, divinyltetramethyldisilazane, dimethyltetravinyldisilazane; dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, alkyl modified Silicone oil, chloroalkyl-modified silicone oil, chlorophenyl-modified silicone oil, fatty acid-modified silicone oil, polyether-modified silicone oil, alkoxy-modified silicone oil, carbinol-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, and terminal reaction Silicone oil such as water-soluble silicone oil; hexamethylcyclotrisiloxane, octamethylcyclotetrasilo Siloxanes such as xane, decamethylcyclopentasiloxane, hexamethyldisiloxane, octamethyltrisiloxane; fatty acids and metal salts thereof such as undecyl acid, lauric acid, tridecylic acid, dodecylic acid, myristic acid, palmitic acid, pentadecylic acid, Long chain fatty acids such as stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, linoleic acid and arachidonic acid, and salts of the fatty acids with metals such as zinc, iron, magnesium, aluminum, calcium, sodium and lithium. Among these, alkoxysilanes, silazanes, and straight silicone oils are preferably used because they can be easily subjected to a hydrophobic treatment. Such hydrophobizing agents can be used alone or in admixture of two or more. Moreover, the hydrophobic treatment agent can be used in a stepwise manner to surface-treat silica particles to achieve the required hydrophobicity, fluidity, etc. depending on the application.

  As a treatment amount of the hydrophobic treatment agent to the silica particles A, the amount of carbon derived from the hydrophobic treatment agent is preferably 4.5% by mass or less. If the amount of carbon is within the above range, the amount of the hydrophobizing agent used is suitable, and a decrease in fluidity of the silica particles is prevented. On the other hand, if the amount of carbon derived from the hydrophobizing agent is large, the amount of the treating agent on the surface of the silica particles becomes excessive, so that the characteristics of the pores of the silica particles A are difficult to appear. As a result, toner charging uniformity is reduced. The carbon content is more preferably 1.0% by mass or less, and particularly preferably 0.08% by mass or less.

<Method for measuring carbon content of silica particles>
The carbon content of the silica particles is measured using a carbon / sulfur analyzer (EMIA-320 manufactured by HORIBA). About 0.3 g of a sample is weighed accurately in the above-mentioned crucible for measuring apparatus, and tin (supplement number 9052012500) 0.3 g ± 0.05 g and tungsten (supplement number 9051104100) 1.5 g ± 0.1 g are used as auxiliary combustors. Added. Thereafter, according to the instruction manual attached to the measuring device, the surface hydrophobic group derived from the hydrophobizing agent of the silica particles is thermally decomposed into CO ₂ at 1100 ° C. in an oxygen atmosphere. Thereafter, the amount of carbon contained in the silica particles A is determined from the amount of CO ₂ obtained.

  Silica particles A preferably have a immobilization ratio of the hydrophobizing agent to silica particles A of 90% or more. If the immobilization rate is within the above range, good chargeability, fluidity, and transferability can be imparted to the toner regardless of the environment.

<Method for Measuring Immobilization Rate of Hydrophobizing Agent for Silica Particles>
The immobilization ratio of the hydrophobizing agent to the silica particles was measured by the following method. Place 0.50 g of silica fine particles and 40 ml of chloroform in an Erlenmeyer flask, cap and stir for 2 hours. Thereafter, stirring is stopped and the mixture is allowed to stand for 12 hours, and then centrifuged to remove all the supernatant. Centrifugation is performed using a Bn1 rotor and a poly centrifuge tube for Bn1 rotor in a centrifuge H-9R (manufactured by KOKUSA) under the conditions of 20 ° C., 10,000 rpm, and 5 minutes.

  The centrifuged silica particles are put again into an Erlenmeyer flask, 40 ml of chloroform is added, the lid is put on, and the mixture is stirred for 2 hours. Thereafter, stirring is stopped and the mixture is allowed to stand for 12 hours, and then centrifuged to remove all the supernatant. Repeat this operation two more times. And the obtained sample is dried at 50 degreeC for 2 hours using a thermostat. Further, the pressure is reduced to 0.07 MPa and dried at 50 ° C. for 24 hours to sufficiently volatilize chloroform.

  The amount of carbon of the silica particles treated with chloroform as described above and the silica particles before being treated with chloroform were measured by the method described in the above “Method for measuring the amount of carbon of silica particles”, and the following equation was obtained: To calculate the immobilization rate.

Immobilization rate of hydrophobizing agent for silica particles (%) = (carbon content of silica particles treated with chloroform / carbon content of silica particles) × 100
Hereinafter, the manufacturing method of the silica particle A is demonstrated. The silica particles A of the present invention are not particularly limited to the production method as long as the volume average particle diameter (Dv), the coefficient of variation in volume particle size distribution, the pore diameter, and the pore volume are within the ranges specified in the present application. Silica particle production methods include combustion methods obtained by burning silane compounds (ie, fumed silica production methods), deflagration methods obtained by explosively burning metallic silicon powder, sodium silicate and mineral acid. Wet method obtained by the neutralization reaction of the above (the one synthesized under alkaline conditions is called precipitation method, the one synthesized under acidic conditions is called gel method), the sol-gel method obtained by hydrolysis of alkoxysilane such as hydrocarbyloxysilane ( The so-called Stöber method). Among these, as a method for producing silica particles having a volume average particle diameter (Dv) of around 100 nm, a sol-gel method capable of sharpening the particle size distribution as compared with other methods is preferable.

  A method for producing silica particles by the sol-gel method will be described below. First, a silica sol suspension is obtained by hydrolyzing and condensing alkoxysilane with a catalyst in an organic solvent in which water is present. Then, the solvent is removed from the silica sol suspension and dried to obtain silica particles. The present inventors have found that the surface pore state of the silica particles can be controlled within the above range by controlling the reaction conditions at this time. For example, under conditions where the condensation reaction is difficult to proceed, such as when the reaction time is shortened, shrinkage during drying tends to occur, and the pore diameter and pore volume tend to be small.

  The silica particles thus obtained are usually hydrophilic and have many surface silanol groups. Therefore, it is preferable to dehydrate and condense the silanol groups of the silica particles by heat treatment at 300 ° C. to 500 ° C. Thereby, the silanol groups of the silica particles can be dehydrated and condensed, the amount of silanol groups can be reduced, and moisture absorption of the silica particles can be suppressed.

  When the silica particles are treated with the hydrophobizing agent, the timing of the heat treatment at 300 ° C. to 500 ° C. may be before, after or at the same time as the hydrophobizing treatment. However, when heat treatment is performed after the hydrophobization treatment, the hydrophobization treatment agent may be thermally decomposed, and the above-described immobilization rate of the hydrophobization treatment agent may not be obtained. Preferably it is done.

  Further, the silica particles A may be crushed in order to facilitate the monodispersion of the silica particles A on the surface of the toner particles or to exhibit a stable spacer effect. As the timing of the crushing treatment, it is preferable that the crushing treatment is performed before the surface treatment with the hydrophobizing agent because the surface of the silica particles can be uniformly treated with the hydrophobizing agent.

  The addition amount (external addition amount) of the silica particles A to the toner is preferably 0.01 parts by mass or more and 2.50 parts by mass or less with respect to 100 parts by mass of the toner particles. When the addition amount of the silica particles A is within the above range, the above-described effect of the silica particles A is exhibited well. The addition amount of the silica particles A to the toner is more preferably from 0.10 parts by mass to 2.00 parts by mass with respect to 100 parts by mass of the toner particles.

  The weight average particle diameter (D4) of the toner of the present invention is preferably 4.0 μm or more and 9.0 μm or less. Preferably they are 5.0 micrometers or more and 7.5 micrometers or less. When the weight average particle diameter of the toner is within the above range, the silica particles A can be present on the toner in a uniform and appropriate amount. Thereby, the effect by the pores of the silica particles A is easily obtained, overcharging is suppressed, and deterioration of fog and deterioration of halftone uniformity are prevented.

<Measuring method of weight average particle diameter (D4) and number average particle diameter (D1)>
The weight average particle diameter (D4) and number average particle diameter (D1) of the toner are calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels. As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows. On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked. In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

  The specific measurement method is as follows.

  (1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.

  (2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.

  (3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.

  (4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

  (5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

  (6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . Measurement is performed until the number of measured particles reaches 50,000.

  (7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) and the number average particle diameter (D1) are calculated. The “average diameter” on the “analysis / volume statistic (arithmetic average)” screen when the graph / volume% is set in the dedicated software is the weight average particle size (D4). When the number% is set, the “average diameter” on the “analysis / number statistics (arithmetic average)” screen is the number average particle diameter (D1).

  The toner of the present invention preferably contains one or more release agents. The total amount of the release agent contained in the toner is preferably 2.5 to 25.0 parts by mass in 100 parts by mass of the toner particles. Further, the total amount of the release agent contained in the toner particles is more preferably 4.0 parts by mass or more and 20 parts by mass or less, and further preferably 6.0 parts by mass or more and 18.0 parts by mass or less. . In particular, in order to maintain and improve both fixability and developability at a high level, a toner in which the above silica particles A are added to a system in which a large amount of a release agent is added is effective. Examples of the release agent include the following. Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, Fischer-Tropsch wax, paraffin wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof ; Waxes mainly composed of fatty acid esters such as carnauba wax and montanic acid ester wax, and deoxidized part or all of fatty acid esters such as deoxidized carnauba wax; palmitic acid, stearic acid, montanic acid, etc. Saturated linear fatty acids; Unsaturated fatty acids such as brandic acid, eleostearic acid, parinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, Saturated alcohols such as alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; , Saturated fatty acid bisamides such as hexamethylenebisstearic acid amide; unsaturated bisamides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N ′ dioleyl adipic acid amide, N, N ′ dioleyl sebacic acid amide Fatty acid amides; aromatic bisamides such as m-xylene bis-stearic acid amide and N, N ′ distearyl isophthalic acid amide; calcium stearate, calcium laurate, zinc stearate, magnesium stearate, etc. Aliphatic metal salts (generally called metal soaps); waxes grafted with aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; fatty acids such as behenic acid monoglycerides and polyvalent A partially esterified product of alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of vegetable oil or the like.

  Examples of the binder resin for toner include the following. Polystyrene; Homopolymers of styrene-substituted products such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic Acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer Styrene copolymers such as polymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers; acrylic resins; methacrylic resins; polyvinyl acetate ;Silicone resin; Riesuteru resin; polyamide resin; furan resins, epoxy resins, xylene resins. These resins are used alone or in combination.

  The toner particles used in the present invention can be produced using a known pulverization method and polymerization method. In particular, since the polymerization method can obtain toner particles that are close to a true sphere and have less surface irregularities than the pulverization method, the effect of imparting transferability of the silica particles A can be expressed synergistically. preferable. Among the polymerization methods, it is particularly preferable to obtain toner particles by a suspension polymerization method. Hereinafter, a method for producing toner particles by the suspension polymerization method will be described. Dispersers such as homogenizers, ball mills, colloid mills, ultrasonic dispersers, etc. containing polymerizable monomer compositions containing a polymerizable monomer, a colorant and a release agent, and other additives as required. Or suspended in an aqueous medium containing a dispersion stabilizer. Then, using the polymerization initiator, the polymerizable monomer in the polymerizable monomer composition is polymerized to prepare toner particles. The polymerization initiator may be added when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Further, a polymerization initiator dissolved in a polymerizable monomer or a solvent can be added immediately after granulation and before starting the polymerization reaction.

  As the polymerizable monomer, 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. Examples of the monofunctional polymerizable monomer include the following. Styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, p- Styrene derivatives such as n-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene; 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- Acrylic polymerizable monomers such as 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, dibutyl phosphate ethyl Methacrylic polymerizable monomers such as methacrylate; methylene aliphatic monocarboxylic acid ester; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl Vinyl ethers such as ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropyl ketone;

  The following are mentioned as a polyfunctional polymerizable monomer. 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- (acryloxy-diethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-bu Lenglycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxy-diethoxy) phenyl) propane, 2,2′-bis ( 4- (methacryloxy polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether.

  A monofunctional polymerizable monomer is used individually or in combination of 2 or more types or in combination with a polyfunctional polymerizable monomer. The polyfunctional polymerizable monomer can also be used as a crosslinking agent.

  As a polymerization initiator used in the polymerization of the polymerizable monomer, an oil-soluble initiator and / or a water-soluble initiator is used. Examples of oil-soluble initiators include the following. 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4 -Azo compounds such as methoxy-2,4-dimethylvaleronitrile; acetylcyclohexylsulfonyl peroxide, diisopropylperoxycarbonate, decanonyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, acetyl peroxide, t-butyl Peroxy-2-ethylhexanoate, benzoyl peroxide, t-butyl peroxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, t-butyl hydroper Kisaido, di -t- butyl peroxide, peroxide initiators such as cumene hydroperoxide. The following are mentioned as a water-soluble initiator. Ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-dimethyleneisobutyroamidine) hydrochloride, 2,2'-azobis (2-aminodinopropane) hydrochloride, azobis (isobutylamidine) Hydrochloride, sodium 2,2′-azobisisobutyronitrile sulfonate, ferrous sulfate or hydrogen peroxide. In order to control the degree of polymerization of the polymerizable monomer, a chain transfer agent, a polymerization inhibitor or the like can be further added and used.

  As the crosslinking agent, a compound having two or more polymerizable double bonds is used. Specifically, 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; And divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; and compounds having three or more vinyl groups. These are used alone or as a mixture.

As the colorant, the following black, yellow, magenta and cyan colorants can be used.
As the black colorant, carbon black or a magnetic material can be used. Further, the color and toner resistance can be adjusted by mixing the following color materials.

  As the pigment-based yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 3, 7, 10, 12, 13, 14, 15, 17, 23, 24, 60, 62, 74, 75, 83, 93, 94, 95, 99, 100, 101, 104, 108, 109, 110 111, 117, 123, 128, 129, 138, 139, 147, 148, 150, 155, 166, 168, 169, 177, 179, 180, 181, 183, 185, 191: 1, 191, 192, 193 199. Examples of the dye-based yellow colorant include C.I. I. solvent Yellow 33, 56, 79, 82, 93, 112, 162, 163, C.I. I. Disperse Yellow 42, 64, 201, 211 are listed.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, C.I. I. And CI Pigment Bio Red 19.

  As the cyan colorant, phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds are used. Specifically, C.I. I. Pigment blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66.

  The colorants can be used alone or mixed and further used in the form of a solid solution. In the present invention, the colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHT transparency, and dispersibility in the toner. The amount of the colorant added is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

  In order to keep the chargeability of the toner stable, it is preferable to use a charge control agent for the toner. Examples of negatively charged charge control agents include the following. Monoazo metal compound, acetylacetone metal compound, aromatic oxycarboxylic acid, aromatic dicarboxylic acid, oxycarboxylic acid and dicarboxylic acid-based metal compound, aromatic oxycarboxylic acid, aromatic mono- and polycarboxylic acid and metal salt thereof, Anhydrides, esters, phenol derivatives such as bisphenol, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, resin-based charge control agents. Examples of the positive charge control agent include the following. Nigrosine-modified products of nigrosine and fatty acid metal salts, etc .; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like Phosphonium salts and other onium salts and their lake pigments; triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid Acid, ferricyanide, ferrocyanide, etc.); metal salt of higher fatty acid; diorganotin oxide such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; DOO, dioctyl tin borate, such as diorganotin tin borate such dicyclohexyl tin borate; resin charge control agent. These can be used alone or in combination of two or more.

  Among them, as the charge control agent, a metal-containing salicylic acid compound is preferable, and in particular, the metal is aluminum or zirconium. A particularly preferred control agent is an aluminum salicylate compound. The content of the charge control agent is preferably 0.01 parts by mass or more and 20.00 parts by mass or less per 100 parts by mass of the binder resin. More preferably, 0.50 parts by mass or more and 10.00 parts by mass or less are used.

  The toner of the present invention may be externally added with inorganic fine powder other than silica particles A in order to improve charging stability, developability, fluidity, transferability, etc., and to obtain a stable high image quality over a longer period of time. preferable. Examples of the inorganic fine powder include metal oxides such as silica, alumina, and titania, composite oxides thereof, and carbon fluoride. Two or more kinds may be used in combination. In particular, silica, alumina, titania, and composite oxides thereof are preferable in that the fluidity and chargeability of the toner are maintained well and the adsorption performance to the toner particles is high.

  The addition amount of the inorganic fine powder is preferably 0.01 parts by mass or more and 3.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 2.5 parts by mass or less with respect to 100 parts by mass of the toner particles. When the amount of the inorganic fine powder added is more than 3.0 parts by weight, the silica particles A tend to be detached from the toner. The detached silica particles may contaminate the developer constituting material and the image forming system member, and may have adverse effects such as deterioration of the charging characteristics of the toner and accompanying fog deterioration. The average primary particle size of the inorganic fine powder is preferably 5 nm or more and 70 nm or less. If the average primary particle diameter of the inorganic fine powder is within the above range and the addition amount is within the above range, the surface of the toner particles can be appropriately covered with the inorganic fine powder. As a result, the inorganic fine powder covering the toner particles is frequently contacted with the silica particles A, and it is easy to obtain the effect of improving the charging uniformity of the toner. The addition amount of the inorganic fine powder is preferably larger than the addition amount of the silica particles A. As a result, the charging uniformity of the toner can be maintained well over a long period of time due to the synergistic effect of the silica particles A and the inorganic fine powder.

[Measurement method of average primary particle size of inorganic fine powder]
The average primary particle size of the inorganic fine powder is the average value of the long diameter of 300 primary particles having a major axis of 1 nm or more in a visual field enlarged by 30,000 to 50,000 times by observing the inorganic fine powder with a transmission electron microscope. Is calculated. When the sampled particles are so small that the particle size cannot be measured at an enlargement magnification of 50,000 times, the enlarged photograph is further enlarged so that the measured sample actual particle size is 5 mm or more.
The inorganic fine powder is preferably hydrophobized. The hydrophobizing method and the hydrophobizing agent are the same as in the case where the silica particles A are hydrophobized.

  The total amount of silica particles A and inorganic fine powder added to the toner is preferably 0.5 parts by mass or more and 4.5 parts by mass or less, and 0.8 parts by mass or more and 3.5 parts by mass or less with respect to 100 parts by mass of the toner particles. The following is more preferable. If the total addition amount of the silica particles A and the inorganic fine powder is within the above range, sufficient toner fluidity can be obtained, and deterioration of fog due to a decrease in toner chargeability can be prevented.

  In addition to the inorganic fine powder, known external additives such as charge controllable particles, abrasives and anti-caking agents may be used. Examples of the charge controllable particles include metal oxides (tin oxide, titania, zinc oxide, silica, alumina, etc.) and carbon black. Abrasives include metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, etc.) , Calcium carbonate, etc.). Anti-caking agents; conductivity imparting agents such as zinc oxide, antimony oxide and tin oxide; and developability improvers.

  Further, a lubricant can be used in order to reduce member contamination. Examples of the lubricant include fluorine resin powder (polyvinylidene fluoride, polytetrafluoroethylene, etc.) and fatty acid metal salt (zinc stearate, calcium stearate, etc.). Of these, zinc stearate is preferably used. The addition amount of these charge control particles, abrasives, anti-caking agents, etc. (excluding silica particles A and the above-mentioned inorganic fine powder) is 0.01 parts by mass or more and 2.50 parts by mass with respect to 100 parts by mass of the toner particles. Part or less, more preferably 0.10 parts by mass or more and 2.00 parts by mass or less.

  The toner of the present invention is a toner for a developing system in which a toner for a high speed system, a toner for an oilless fixing system, a toner for a cleanerless system, a carrier in a developing device deteriorated by long-term use is sequentially collected and a fresh carrier is replenished. Can be used as Further, the present invention can be applied to an image forming method using a known one-component development method or two-component development method. In particular, since the toner of the present invention has very good transferability and can obtain a stable image over a long period of time, an image forming method having an intermediate transfer member, cleaner-less, regardless of one-component development method or two-component development method. It can be suitably used for an image forming method having a system.

  When the toner of the present invention is used as a two-component developer, it can be used regardless of whether it is full color or monochrome. Two-component developer for auto-refresh image forming method, two-component developer for high-speed system image forming method, two-component developer for oilless fixing image forming method, two-component developer for cleanerless image forming method, TACT The present invention can be applied to known development methods such as a two-component developer for an image forming method and a two-component developer for an image forming method that supplies a replenishment developer to a developing device using an air flow.

[Preparation of Silica Particle 1]
In a 3 L glass reactor equipped with a stirrer, a dropping funnel and a thermometer, 687.9 g of methanol, 42.0 g of pure water and 47.1 g of 28 mass% ammonia water were added and mixed. The obtained solution was adjusted to 35 ° C., and 1100.0 g (7.23 mol) of tetramethoxysilane and 395.2 g of 5.4 mass% aqueous ammonia were begun simultaneously with stirring. Tetramethoxysilane was added dropwise over 5 hours and ammonia water was added over 4 hours. Even after the dropping was finished, the mixture was further stirred for 0.2 hours for hydrolysis to obtain a methanol-water dispersion of hydrophilic spherical sol-gel silica fine particles. Next, an ester adapter and a condenser tube were attached to the glass reactor, and the dispersion was heated to 65 ° C. to distill off methanol. Thereafter, the same amount of pure water as the distilled methanol was added. This dispersion was sufficiently dried at 80 ° C. under reduced pressure. The obtained silica particles were heated at 400 ° C. for 10 minutes in a thermostatic bath. The said process was implemented 20 times and the obtained silica particle was crushed with the pulverizer (made by Hosokawa Micron Corporation).

  Thereafter, 500 g of silica particles were charged into a polytetrafluoroethylene inner cylinder type stainless steel autoclave having an inner volume of 1000 ml. After the inside of the autoclave was replaced with nitrogen gas, 0.5 g of HMDS (hexamethyldisilazane) and 0.1 g of water were atomized with a two-fluid nozzle while rotating the stirring blade attached to the autoclave at 400 rpm. The silica powder was sprayed uniformly. After stirring for 30 minutes, the autoclave was sealed and heated at 200 ° C. for 2 hours. Subsequently, deammonia was performed by reducing the pressure in the system while heating to obtain silica particles 1. Table 2 shows the physical properties of the silica particles 1.

[Preparation of Silica Particles 2 to 16]
Table 1 shows the amount of methanol in the initial reactor, the dripping time of tetramethoxysilane and 28% by mass of ammonia water, the stirring duration after appropriate reduction, and the heating temperature at the time of distilling off methanol in the production process of silica particles 1. Changed to Other than that was carried out similarly to the preparation process of the silica particle 1, and obtained the silica particles 2-16. Table 2 shows the physical properties of the silica particles 2 to 16.

[Preparation of Silica Particles 17]
Silica particles (fumed silica) having a volume average particle diameter (Dv) of 90 nm were prepared by a combustion method. The coefficient of variation in volume particle size distribution was 35%. This was classified to obtain silica particles having a volume average particle diameter (Dv) of 100 nm and a coefficient of variation of 21% in the volume particle size distribution. This was surface-treated with HMDS in the same manner as the silica particles 1 to obtain silica particles 17. Table 2 shows the physical properties of the silica particles 17.

[Preparation of silica particles 18]
In accordance with the method described in JP-A-60-255602, silica particles having a volume average particle diameter (Dv) of 150 nm were prepared by deflagration using metal silicon as a raw material. The coefficient of variation in volume particle size distribution was 30%. This was classified to obtain silica particles having a volume average particle size (Dv) of 120 nm and a coefficient of variation of 21% in the volume particle size distribution. This was surface-treated with HMDS in the same manner as the silica particles 1 to obtain silica particles 18. Table 2 shows the physical properties of the silica particles 18.

[Preparation of Silica Particles 19 to 25]
Table 1 shows the amount of methanol in the initial reactor, the dripping time of tetramethoxysilane and 28% by mass of ammonia water, the stirring duration after appropriate reduction, and the heating temperature at the time of distilling off methanol in the production process of silica particles 1. Changed to Other than that was carried out similarly to the preparation process of the silica particle 1, and obtained the silica particle 19 thru | or 25. Table 2 shows the physical properties of the silica particles 19 to 25.

[Production of charge control resin]
In a pressurizable reaction vessel equipped with a reflux tube, a stirrer, a thermometer, a nitrogen introduction tube, a dropping device and a decompression device, 250 parts by mass of methanol, 150 parts by mass of 2-butanone and 100 parts by mass of 2-propanol, As monomers, 77 parts by mass of styrene, 15 parts by mass of 2-ethylhexyl acrylate, and 8 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid were added and heated to reflux temperature while stirring. A solution obtained by diluting 1 part by mass of t-butylperoxy-2-ethylhexanoate as a polymerization initiator with 20 parts by mass of 2-butanone was added dropwise over 30 minutes, and stirring was continued for 5 hours. Further, a solution obtained by diluting 1 part by mass of t-butylperoxy-2-ethylhexanoate with 20 parts by mass of 2-butanone was added dropwise over 30 minutes and stirred for 5 hours to complete the polymerization. While maintaining the temperature, 500 parts by mass of deionized water was added, and the mixture was stirred at 100 rpm for 2 hours so as not to disturb the interface between the organic layer and the aqueous layer. Then, after standing still for 30 minutes and separating the layers, the aqueous layer was discarded, and anhydrous sodium sulfate was added to the organic layer for dehydration.

  Next, the polymer obtained after the polymerization solvent was distilled off under reduced pressure was coarsely pulverized to 100 μm or less using a cutter mill equipped with a 150 mesh screen. The obtained charge control resin 1 having a sulfur atom had Tg = 58 ° C., Mp = 13,000, and Mw = 30,000.

<Example 1>
[Production of Toner 1]
With respect to 100 parts by mass of the styrene monomer, C.I. I. 16.5 parts by mass of Pigment Blue 15: 3 and 3.0 parts by mass of an aluminum compound of di-tertiary butylsalicylic acid [Bontron E88 (manufactured by Orient Chemical Industries)] were prepared. These were introduced into an attritor (manufactured by Mitsui Mining Co., Ltd.) and stirred at 200 rpm at 25 ° C. for 180 minutes using zirconia beads (140 parts by mass) with a radius of 1.25 mm to prepare a master batch dispersion 1. . On the other hand, after adding 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution to 710 parts by mass of ion-exchanged water and heating to 60 ° C., 67.7 parts by mass of 1.0 M CaCl ₂ aqueous solution was gradually added. Thus, an aqueous medium containing a calcium phosphate compound was obtained.
Master batch dispersion 1 40 parts by mass Styrene monomer 28 parts by mass n-butyl acrylate monomer 18 parts by mass Low molecular weight polystyrene 20 parts by mass (Mw = 3,000, Mn = 1,050, Tg = 55 ° C)
Hydrocarbon wax 9 parts by mass (Fischer-Tropsch wax, peak temperature of maximum endothermic peak = 78 ° C., Mw = 750)
Charge control resin 1 0.3 parts by mass Polyester resin 5 parts by mass (terephthalic acid: isophthalic acid: propylene oxide modified bisphenol A (2 mol adduct): ethylene oxide modified bisphenol A (2 mol adduct) = 30: 30 : 30:10 polycondensate, acid value 11, Tg = 74 ° C., Mw = 11,000, Mn = 4,000)
The above material was heated to 65 ° C., and uniformly dissolved and dispersed at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). In this, 7.1 mass part of 70% toluene solution of polymerization initiator 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate was dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition is charged into the aqueous medium, and stirred at 10,000 rpm for 10 minutes with a TK homomixer at a temperature of 65 ° C. and in an N ₂ atmosphere. Granulated. Thereafter, the temperature was raised to 67 ° C. while stirring with a paddle stirring blade, and when the polymerization conversion rate of the polymerizable vinyl monomer reached 90%, a 0.1 mol / L sodium hydroxide aqueous solution was added. The pH of the aqueous dispersion medium was adjusted to 9. Furthermore, it heated up at 80 degreeC with the temperature increase rate of 40 degreeC / h, and was made to react for 4 hours. After completion of the polymerization reaction, the residual monomer in the toner particles was distilled off under reduced pressure. After cooling the aqueous medium, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 6 hours to dissolve the calcium phosphate salt. The toner particles were separated by filtration and washed with water, and then dried at a temperature of 40 ° C. for 48 hours to obtain cyan toner particles 1.

  To 100 parts by mass of toner particles 1, 1.0 part by mass (number average primary particle size: 12 nm) of silica fine powder surface-treated with 0.8 parts by mass of silica particles 1 and silicone oil was added to a Henschel mixer FM10B ( Toner 1 was obtained by dry mixing at 4000 rpm for 5 minutes using Mitsui Mining Co., Ltd. The toner 1 was evaluated according to the following image evaluation method. The obtained evaluation results are shown in Table 3.

[Image evaluation]
As the image forming apparatus, a modified machine of a commercially available laser printer LBP-4700 (manufactured by HP) was used. The process speed is 240 mm / sec, a SUS blade having a thickness of 8 μm is used as a toner regulating member, and the toner regulating member is modified so that a blade bias of −200 V can be applied to the developing bias. A toner cartridge (215 g) filled in a cyan cartridge was mounted on the cyan station of the printer, and a dummy cartridge was mounted on the other, and an image output test was performed.
In a low-temperature and low-humidity environment (temperature: 15.0 ° C., humidity: 10% RH), the following evaluation was performed after 10,000 sheets and 20,000 sheets of images having an initial printing rate of 1% were printed. As the durable paper, LETTER size XEROX4200 paper (manufactured by XEROX, 75 g / m ² ) was used.

(Halftone uniformity)
A halftone (30H) image was output, and density unevenness of the 30H image was visually observed and evaluated based on the following criteria. The 30H image is a halftone image when 256 gradations are displayed in hexadecimal, 00H is solid white, and FFH is solid black. As the evaluation paper, LETTER size XEROX 4200 paper (manufactured by XEROX, 75 g / m ² ) was used.
Rank A: The image is very uniform and the image is very clear.
Rank B: Excellent image uniformity and good image.
Rank C: The image quality has no problem in practical use.
Rank D: The image has poor uniformity and is not practically preferable.

(Fog)
A full white image was output at a process speed of 120 mm / sec. An Amber filter was set in “REFLECTOMETER MODEL TC-6DS” (manufactured by Tokyo Denshoku Co., Ltd.), and the reflectance (%) of the non-image part of the printout image was measured. The obtained reflectance was evaluated using a numerical value (%) subtracted from the reflectance (%) of unused printout paper (standard paper) measured in the same manner. The smaller the numerical value, the more image fog is suppressed. LETTER size HP ColorLaser Photo Paper, Glossy (HP, 220 g / m ² ) was used as the evaluation paper.
Rank A: The difference in reflectance is less than 0.5.
Rank B: The difference in reflectance is 0.5 or more and less than 1.0.
Rank C: The difference in reflectance is 1.0 or more and less than 2.0.
Rank D: The difference in reflectance is 2.0 or more.

(Transfer efficiency)
The transfer efficiency from the photoreceptor to the transfer paper was measured. A solid image of 10 cm ² is formed on the photoconductor, and the weight of the toner on the photoconductor (W1) and the weight of the toner on the paper after transfer (W2) are measured, and the ratio of both: W2 / W1 × 100 ( %), The transfer efficiency was calculated. A4 size CLC paper (Canon, 80 g / m ² ) was used as the transfer paper.
Rank A: Transfer efficiency is 92% or more.
Rank B: Transfer efficiency is 90% or more and less than 92%.
Rank C: Transfer efficiency is 88% to less than 90%.
Rank D: Transfer efficiency is less than 88%.

<Examples 2 to 18>
[Production of Toners 2 to 18]
In the production process of the toner 1, the silica particles 1 were changed to silica particles 2 to 18. Otherwise, toners 2 to 18 were obtained in the same manner as in the toner 1 production step. Evaluation was performed on toners 2 to 18 in the same manner as toner 1. The obtained evaluation results are shown in Table 3.

<Example 19>
[Preparation of Toner 19]
In the production process of the toner 1, the addition amount of the silica particles 1 was changed to 1.0 part by mass, and the addition amount of the silica fine powder was changed to 0.8 part by mass. Other than that, Toner 19 was obtained in the same manner as in the manufacturing process of Toner 1. The toner 19 was evaluated in the same manner as the toner 1. The obtained evaluation results are shown in Table 3.

<Comparative Examples 1 to 7>
[Production of Toners 20 to 26]
In the production process of the toner 1, the silica particles 1 were changed to silica particles 19 to 25. Otherwise, toners 20 to 26 were obtained in the same manner as in the production step of toner 1. The toners 20 to 26 were evaluated in the same manner as the toner 1. The obtained evaluation results are shown in Table 3.

  In Examples 1 to 19, good results were obtained in all evaluations. On the other hand, Comparative Examples 1 to 7 had an evaluation of D or less in any of the evaluation items. That is, in the high-speed printing under the low temperature and low humidity environment, the effect as in the present invention was not seen.

Claims (3)

A toner having toner particles containing a binder resin and a colorant, and silica particles A,
The silica particles A have a volume average particle diameter (Dv) of primary particles of 70 nm to 500 nm, a coefficient of variation in volume particle size distribution of 23% or less, and an average pore diameter of 5.0 nm to 25.0 nm. There, a toner, wherein the total pore volume measured in the range of less pore diameter 1.7nm or more 300.0nm is not more than 0.02 cm ³ / g or more 1.20cm ³ / g. The silica particles A have a volume average particle diameter (Dv) of primary particles of 80 nm to 200 nm, a coefficient of variation in volume particle size distribution of 10% or less, and an average pore diameter of 15.0 nm to 25.0 nm. There, according to claim 1, wherein the total pore volume measured in the range of less pore diameter 1.7nm or more 300.0nm is not more than 0.05 cm ³ / g or more 0.40 cm ³ / g toner.   The toner according to claim 1, wherein the silica particles A are produced by a sol-gel method.