Toner manufacturing method

Abstract

To provide a pulverization method with which toner particles obtained have a fine particle diameter.SOLUTION: A method for manufacturing toner particles has a step of pulverizing a material to be pulverized containing a binder resin and a colorant with pulverization means. The pulverization means has a stator 104 that has a plurality of convex parts and concave parts on an inner peripheral surface, and a rotor 103 that is attached to a central rotation shaft 107 and has a plurality of convex parts and concave parts on an outer peripheral surface. The stator includes the rotor, and the rotor is arranged so that a surface of the stator and a surface of the rotor face each other with a predetermined gap therebetween. The convex parts and concave parts on the inner peripheral surface and the convex parts and concave parts on the outer peripheral surface are formed along an axial direction of the central rotation shaft. The material to be pulverized is accelerated and injected by a powder supply mechanism and supplied from a supply port 201 to directly collide with the outer peripheral surface of the rotor, and pulverization is performed by the rotation of the rotor in a pulverization area formed by the gap between the stator and the rotor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a toner used in an electrophotographic system, an electrostatic recording system, an electrostatic printing system, and a toner jet system. [Background technology]

[0002] In recent years, full-color electrophotographic copiers have become widespread and are beginning to be applied to the printing market, where there is a demand for high-quality prints at high speed while supporting a wide range of media (paper types). As a specific measure for achieving high image quality, in order to improve dot reproducibility, there is a demand for a toner having a small toner particle size and a uniform particle size distribution that does not contain coarse particles or fine particles. One method for dry toner production is the following. First, a binder resin for fixing to a transfer material, various colorants for imparting color as a toner, and additives such as a release agent and a flowability agent are added and mixed in a dry state. Next, the mixture is melted and mixed in a general-purpose kneading device such as a roll mill or an extruder, cooled and solidified, and then the kneaded mixture is pulverized in various grinding devices, and the resulting coarsely ground product is introduced into various air classifiers for classification to obtain a classified product with a particle size required for a toner. Furthermore, a flowability agent, a lubricant, and the like are externally added as necessary, and the mixture is dry mixed to obtain a toner for use in image formation. One example of a device for finely pulverizing a kneaded material is a mechanical pulverizer that pulverizes the material between a rotor that rotates at high speed and a stator that is arranged around the rotor (Patent Document 1). In this method, the material to be pulverized moves at high speed between the rotor and the stator due to the rotor rotating at high speed, and is pulverized by the collisions that occur at that time. By controlling the rotation speed of the rotor, it is possible to obtain toner having a desired particle size. However, there is a limit to the rotation speed of the rotor in the pulverizer, and therefore there is also a limit to the achievable toner particle size. As a toner micronization device different from a mechanical pulverizer, there is an airflow pulverizer, which uses high-pressure air to move the material to be pulverized at high speed, and pulverizes the material by the collision energy generated at that time (Patent Document 2). With this method, it is possible to impart higher collision energy to the material to be pulverized, but it is known that the particle size distribution of the resulting toner particles is broader than that of a mechanical pulverizer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-237816 A [Patent Document 2] JP 2006-051496 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, in order to improve the image quality of printed matter, a toner having a small particle size and a uniform particle size distribution that does not contain coarse particles or fine particles is required. The sharper the particle size distribution in the toner micronization process, the smaller the amount of fine powder and coarse powder to be removed in the subsequent classification process, which is preferable from the viewpoint of productivity. The object of the present invention is to provide a method for producing toner particles having a small particle size and a sharp particle size distribution in the toner micronization process. [Means for solving the problem]

[0005] In order to solve the above problems of the conventional technology, the present inventors conducted research and discovered that the method of supplying raw materials in a mechanical grinder is related to the particle size and particle size distribution of the obtained toner particles, and thus arrived at the present invention. That is, the present invention provides a method for producing a toner, comprising a step of finely pulverizing a material to be pulverized, the material containing a binder resin and a colorant, by a pulverizing means, The crushing means is A powder supply mechanism for supplying the material to be pulverized; a stator having a plurality of protrusions and recesses on an inner circumferential surface; a rotor attached to a central rotating shaft and having a plurality of protrusions and recesses on an outer circumferential surface; A powder discharge port for discharging the finely pulverized material; having the stator contains the rotor, and the rotor is disposed so that a surface of the stator and a surface of the rotor face each other with a predetermined gap therebetween; The convex portions and concave portions present on the inner peripheral surface of the stator and the outer peripheral surface of the rotor are formed along the axial direction of the central rotation shaft, The protruding portion of the stator and the protruding portion of the rotor face each other with a gap of 0.8 mm or more and 1.4 mm or less, The material to be pulverized is accelerated and sprayed by the powder supply mechanism, and is supplied from a supply port so as to collide directly with the outer circumferential surface of the rotor. In a pulverization region formed by a gap between the stator and the rotor, the material is pulverized by the rotation of the rotor. When the rotor is divided into four equal parts along the central rotation axis, and each of the four equal parts is designated as a first region to a fourth region along the flow of the material to be crushed, (i) the position where the material to be pulverized is accelerated and jetted by the powder supply mechanism and collides with the rotor is the first region; (ii) the powder outlet, Downstream of the flow of the material to be crushed It is set up in The accelerated air speed when accelerating and spraying the material to be pulverized is 10 m / sec or more and 50 m / sec or less when passing through the supply port. The present invention relates to a method for producing a toner. Effect of the Invention

[0006] According to the present invention, it is possible to provide a toner having a small particle size while maintaining high productivity. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram of a typical grinding device. [Diagram 2] FIG. 2 is a diagram of a grinding device used in the present invention. [Diagram 3]FIG. 2 is a diagram illustrating a raw material supply position in the grinding device used in the present invention. [Figure 4] 4A and 4B are diagrams illustrating the uneven shapes of a stator and a rotor. [Diagram 5] FIG. 1 is a diagram of an interlocking tooth grinding device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention is characterized by a raw material supply method in which the material to be pulverized is accelerated and injected into the pulverization chamber using high-pressure air, and the material is directly collided with the rotor rotating at high speed, as opposed to the conventional general mechanical pulverization devices. The mechanical pulverizer for carrying out the present invention will be outlined below.

[0009] ·Device Fig. 1 shows a schematic cross-sectional view of a conventional general mechanical grinding device. The illustrated diagram shows a horizontal type device, but it may be a vertical type device. It is composed of a supply port 101 for supplying the material to be ground and cold air, a rotor 103 having a number of projections and recesses on its outer circumferential surface attached to a central rotating shaft 107, a stator 104 having a number of projections and recesses on its inner circumferential surface arranged at a fixed interval on the outer circumferential surface of the rotor 103, a cold water supply port 109 for circulating cooling water around the outer circumferential surface of the stator, a cold water discharge port 110, and a discharge port 106 for discharging the powder (finely ground material) and cold air after processing.

[0010] In the mechanical pulverizer configured as above, when a predetermined amount of powder raw material is fed into the supply port 101, the raw material is introduced into the pulverization chamber via the front chamber 102. In the pulverization chamber, the rotor 103, which has a number of irregularities on its surface, rotates at high speed, and the stator 104, which also has a number of irregularities on its surface. The material is instantaneously pulverized by the impact generated between the rotor 103 and the stator 104, which also has a number of irregularities on its surface, the number of ultra-high speed vortex flows generated behind the rotor 103, and the high frequency pressure vibrations generated by the impact. The material is then discharged through the discharge port 106. The air carrying the particles passes through the pulverization chamber and is discharged from the discharge port 106. In order to collect the powder after processing, a means for separating the powder in the airflow using a cyclone connected to the discharge port 106 by piping or the like can be used.

[0011] Examples of such mechanical grinding machines include Innomizer (manufactured by Hosokawa Micron Corporation), Cryptoline (manufactured by Kawasaki Heavy Industries, Ltd.), Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.), Tornado Mill (manufactured by Nikkiso Co., Ltd.), etc. These can be used as is or after appropriate modification.

[0012] The base materials for the rotors and stators in mechanical crushers are often carbon steels such as S45C and chrome-molybdenum steels such as SCM. By coating the surface of these base materials with a chrome alloy and then carrying out mechanical surface treatment, the surface hardness and wear resistance of the crushing surface are increased, resulting in rotors and stators with long life, enabling long runs.

[0013] In particular, the coating of the surface of the base material of a chromium alloy containing chromium carbide can be finished uniformly and smoothly by plating, and the friction coefficient can be reduced to improve wear resistance. After plating, a polishing treatment such as buffing or a blasting treatment such as shot blasting may be performed to adjust the surface roughness of the rotor and stator.

[0014] In the present invention, the method of feeding the material to be crushed is changed as described above, and the material is directly fed to the rotor 103 rotating at high speed using compressed air from the material feed port 201 as shown on the right side of Figure 2. At this time, the material to be crushed is accelerated and jetted out, colliding directly with the outer periphery of the rotor 103 and being crushed.

[0015] The left side of Fig. 2 shows a schematic cross-sectional view taken along the DD' plane in the right side of Fig. 2. The multiple convex and concave portions on the surfaces of the rotor and stator are formed along the axial direction of the central rotation shaft of the rotor. In the present invention, fine grinding is carried out in the grinding region formed by the gap between the stator and rotor, and it is important that the material to be ground is supplied from the supply port so that it collides directly with the outer circumferential surface of the rotor. It is believed that this makes it possible to impart higher collision energy to the material to be ground.

[0016] The air speed when the compressed air is accelerated and sprayed also has a large effect on the particle size of the toner particles. The air speed must be between 10 m / sec and 50 m / sec when passing through the supply port. If the air speed is below 10 m / sec, the effect of reducing the particle size of the toner particles cannot be obtained. Furthermore, if the air speed exceeds 50 m / sec, excessive collision energy is applied, and the particle size distribution of the toner particles becomes broad due to over-pulverization.

[0017] FIG. 4 is a schematic diagram of the uneven shape present on the rotor and stator. The interval Db between the convex parts of the rotor and stator is preferably 0.8 mm or more and 1.4 mm or less, and more preferably 0.8 mm or more and 1.2 mm or less. The interval Da between the convex parts of the rotor and stator is preferably 1.0 mm or more and 1.5 mm or less. When Da and Db are in this range, the rotor rotates at high speed, generating a high-speed vortex between the rotor and the stator. This allows the material to be crushed to be efficiently repeatedly collided with the rotor and stator, thereby enabling further fine grinding. In addition, when the material to be crushed in the crushing processing chamber after the collision is finer to a certain particle size, it is quickly discharged from the raw material discharge port due to the influence of the air flow in the processing chamber. This makes it possible to suppress the broadening of the particle size distribution due to over-crushing.

[0018] In order to enhance the effect of the present invention, the angle at which the material to be pulverized is introduced by accelerated injection is also important. The material to be pulverized is supplied so as to face the direction of rotation of the rotor, and the angle θ between the direction of introduction of the material to be pulverized in the left diagram in FIG. 2 and the tangent direction at the raw material introduction port in a plane perpendicular to the rotation axis of the rotor is preferably 20° or more and 80° or less, more preferably 30° or more and 70° or less. The smaller the value of θ, the higher the relative velocity of the material to be pulverized and the rotor at the time of collision can be increased. However, when the collision velocity exceeds a certain value, the material to be pulverized tends to be over-pulverized, and the particle size distribution of the resulting toner particles becomes broad. Also, when θ is large, the relative velocity between the material to be pulverized and the rotor does not increase, and therefore toner particles of the desired particle size cannot be obtained. For the above reasons, θ is preferably in the above range.

[0019] Like the angle of the raw material supply port, the raw material supply position also affects the particle size of the toner particles obtained. That is, when the rotor is divided into four equal parts along the central rotation axis and each of the four equal parts is designated as the first to fourth regions along the flow of the material to be pulverized, (i) the position where the material to be pulverized is accelerated and jetted by the powder supply mechanism and collides with the rotor is the first region, and (ii) the powder discharge port must be provided in the region of the stator facing the fourth region. If this aspect is not satisfied, pulverization in the pulverization processing chamber after air current collision is not performed sufficiently, and toner particles of the desired particle size cannot be obtained.

[0020] FIG. 3 specifically illustrates the above embodiment, and the ratio Lj / Lr of the distance Lj from the end of the rotor on the supply port 101 side to the raw material supply port 201 to the total length Lr of the rotor in FIG. 3 must be 0 or more and 0.25 or less, and preferably 0 or more and 0.15 or less.

[0021] (Toner manufacturing procedure) Next, a procedure for producing a toner using the production method and production apparatus of the present invention will be described.

[0022] First, in the raw material mixing process, at least the binder resin and colorant are weighed out in predetermined amounts as toner internal additives, and mixed. If necessary, a release agent that suppresses the occurrence of hot offset during heat fixing of the toner, a dispersant that disperses the release agent, a charge control agent, etc. may be mixed. Examples of mixing devices include a double con mixer, a V-type mixer, a drum type mixer, a super mixer, a Henschel mixer, a Nauta mixer, etc.

[0023] Furthermore, the toner raw materials blended and mixed as described above are melt-kneaded to melt the resins and disperse the colorant therein. In the melt-kneading step, for example, a batch-type kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. In recent years, single-screw or twin-screw extruders have become mainstream due to their advantages such as continuous production, and for example, a KTK twin-screw extruder manufactured by Kobe Steel, Ltd., a TEM twin-screw extruder manufactured by Toshiba Machine Co., Ltd., a twin-screw extruder manufactured by KCK Corporation, and a Co-kneader manufactured by Buss Co., Ltd. are commonly used. Furthermore, the colored resin composition obtained by melt-kneading the toner raw materials is rolled with a two-roller or the like after melt-kneading, and cooled through a cooling step in which it is cooled with water or the like.

[0024] The cooled colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization step, the colored resin composition is first coarsely pulverized using a crusher, a hammer mill, a feather mill, or the like. Then, the colored resin composition is finely pulverized using a mechanical pulverizer according to the present invention. In this manner, the colored resin composition is pulverized stepwise to a predetermined toner particle size.

[0025] (Toner raw materials) Next, the raw materials of the toner, which contains at least the binder resin and the colorant used in the present invention, will be described.

[0026] <Binding resin> As the binder resin used in the toner used in electrophotography, a general resin can be used, and examples thereof include polyester resin, styrene-acrylic acid copolymer, polyolefin resin, vinyl resin, fluororesin, phenol resin, silicone resin, and epoxy resin. Among these, from the viewpoint of improving low-temperature fixing property, amorphous polyester resin is used, and from the viewpoint of achieving both low-temperature fixing property and hot offset resistance, it is known to use low-molecular-weight polyester and high-molecular-weight polyester in combination. In addition, from the viewpoint of further improving low-temperature fixing property and blocking resistance during storage, crystalline polyester may be used as a plasticizer.

[0027] <Coloring agent> Colorants that can be contained in the toner include the following.

[0028] The colorant may be a known organic pigment or oil-based dye, carbon black, or a magnetic material.

[0029] Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

[0030] Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.

[0031] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

[0032] Examples of black colorants include carbon black, magnetic materials, and those toned to black using the above-mentioned yellow colorants, magenta colorants, and cyan colorants.

[0033] The colorants may be used alone or in combination of two or more.

[0034] <Release agent> If necessary, a release agent for suppressing the occurrence of hot offset during the heat fixing of the toner may be used. Typical examples of the release agent include low molecular weight polyolefins, silicone wax, fatty acid amides, ester waxes, carnauba wax, and hydrocarbon waxes.

[0035] Next, methods for measuring characteristic values ​​according to the present invention and the examples described below will be described.

[0036] <Calculation of accelerated jet speed> The speed of the accelerated injection of the material to be pulverized was calculated from the following formula 1. The volumetric flow rate was measured using a flow meter. (Velocity) = (Volumetric flow rate) / (Effective cross-sectional area of ​​the pipe) (Equation 1)

[0037] (Measurement of toner particle size distribution) <Method of measuring weight average particle size (D4) of toner> The weight average particle diameter (D4) of the toner is measured with an effective measurement channel count of 25,000 channels using a precision particle size distribution measuring device equipped with a 50 μm aperture tube and a fine hole electrical resistance method called "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) for setting measurement conditions and analyzing measurement data, and then the measurement data is analyzed and calculated.

[0038] The electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, for example, "ISOTON II" (manufactured by Beckman Coulter).

[0039] Before carrying out the measurements and analyses, the dedicated software is set up as follows.

[0040] In the "Change Standard Measurement Method (SOM) screen" of the dedicated software, set the total count number in the control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (Beckman Coulter). Press the threshold / noise level measurement button to automatically set the threshold and noise level. In addition, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the aperture tube flush after measurement.

[0041] In the "Pulse to particle size conversion setting screen" of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 1 μm or more and 30 μm or less.

[0042] The specific measurement method is as follows. (1) Pour about 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made exclusively for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture flush" function of the analysis software to remove dirt and air bubbles from inside the aperture tube. (2) Approximately 30 ml of the above-mentioned aqueous electrolyte solution is placed in a 100 ml flat-bottom glass beaker, and approximately 0.3 ml of a solution prepared by diluting "Contaminon N" (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, with a pH of 7, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added as a dispersant. (3) A specified amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser "Ultrasonic Dispension System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.) that has two oscillators with an oscillation frequency of 50 kHz built in with a phase shift of 180 degrees and an electrical output of 120 W, and approximately 2 ml of the Conaminon N is added to this water tank. (4) The beaker (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid surface of the electrolyte solution in the beaker is maximized. (5) While the electrolyte solution in the beaker in (4) is irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolyte solution and dispersed. Then, ultrasonic dispersion treatment is continued for another 60 seconds. During ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be 10°C or higher and 40°C or lower. (6) Using a pipette, add the electrolyte solution (5) in which the toner is dispersed to the round-bottom beaker (1) placed in the sample stand, and adjust the measurement concentration to about 5%. Then, measurements are continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software that comes with the device, and the weight-average particle size (D4) is calculated. Note that when the dedicated software is set to Graph / Volume%, the "Average diameter" on the Analysis / Volume Statistics (Arithmetic Mean) screen is the weight-average particle size (D4).

[0043] <Method of measuring the number-average particle size (D1) of toner> In step (7) of the measurement method for the weight-average particle diameter (D4) of toner, when you select Graph / Number % in the dedicated software, the “Average diameter” on the Analysis / Number statistics (arithmetic mean) screen is the number-average particle diameter (D1). EXAMPLES

[0044] <Production Example of Polyester Resin L> Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: 72.0 parts by mass (0.20 moles; 100.0 mol% based on the total number of moles of polyhydric alcohol) Terephthalic acid: 28.0 parts by mass (0.17 moles; 100.0 mol% based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts by mass The above materials were weighed and placed in a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen inlet tube, and a thermocouple. Next, the atmosphere in the flask was replaced with nitrogen gas, and the temperature was gradually raised with stirring, and the reaction was carried out for 4 hours at a temperature of 200°C with stirring.

[0045] The pressure inside the reaction vessel was then reduced to 8.3 kPa and maintained for 1 hour, after which the vessel was cooled to 180° C. and returned to atmospheric pressure.

[0046] Trimellitic anhydride: 3 parts by mass (0.01 mole; 4.0 mol% based on the total number of moles of polycarboxylic acids) tert-Butylcatechol (polymerization inhibitor): 0.1 parts by mass Thereafter, the above materials were added, the pressure in the reaction tank was reduced to 8.3 kPa, and the reaction was carried out for 1 hour while maintaining the temperature at 180°C. After it was confirmed that the softening point measured in accordance with ASTM D36-86 reached 90°C, the temperature was reduced to stop the reaction, thereby obtaining polyester resin L, which is a binder resin component.

[0047] <Production Example of Polyester Resin H> Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: 72.3 parts by mass (0.20 moles; 100.0 mol% based on the total number of moles of polyhydric alcohol) Terephthalic acid: 18.3 parts by mass (0.11 moles; 65.0 mol% based on the total number of moles of polycarboxylic acids) Fumaric acid: 2.9 parts by mass (0.03 moles; 15.0 mol% based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts by mass The above materials were weighed and placed in a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen inlet tube, and a thermocouple. Next, the atmosphere in the flask was replaced with nitrogen gas, and the temperature was gradually raised with stirring, and the reaction was carried out for 2 hours at a temperature of 200°C with stirring.

[0048] The pressure in the reactor was then reduced to 8.3 kPa and maintained for 1 hour, after which it was cooled to 180 and returned to atmospheric pressure.

[0049] Trimellitic anhydride: 6.5 parts by mass (0.03 moles; 20.0 mol% based on the total number of moles of polycarboxylic acids) tert-Butylcatechol (polymerization inhibitor): 0.1 parts by mass Thereafter, the above materials were added, the pressure in the reaction tank was reduced to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 160°C. After it was confirmed that the softening point measured in accordance with ASTM D36-86 reached 137°C, the temperature was reduced to stop the reaction, and polyester resin H, which is a binder resin component, was obtained.

[0050] <Crystalline polyester resin> 1,6-Hexanediol: 34.5 parts by mass (0.29 moles; 100.0 mol% based on the total number of moles of polyhydric alcohol) Dodecanedioic acid: 65.5 parts by mass (0.28 moles; 100.0 mol% based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate: 0.5 parts by weight The above materials were weighed and placed in a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen inlet tube, and a thermocouple. After replacing the atmosphere in the flask with nitrogen gas, the temperature was gradually raised with stirring, and the reaction was carried out for 3 hours at a temperature of 140°C with stirring.

[0051] Next, the above materials were added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the temperature was maintained at 200° C. while the reaction was carried out for 4 hours.

[0052] Furthermore, the pressure in the reaction tank was gradually released to return to normal pressure, and then one or more aliphatic compounds selected from the group consisting of aliphatic monocarboxylic acids and aliphatic monoalcohols shown in Table 2 were added in an amount of 7.0 mol % relative to 100.0 mol % of the raw material monomer, and the reaction was carried out at 200° C. for 2 hours under normal pressure.

[0053] Thereafter, the pressure inside the reaction vessel was reduced again to 5 kPa or less, and the mixture was reacted at 200° C. for 3 hours to obtain a crystalline polyester resin.

[0054] <Production of Crushed Material for Toner> Amorphous polyester resin L 80 parts by weight Amorphous polyester resin H 20 parts by weight Crystalline polyester resin 5 parts by weight Fischer-Tropsch wax (hydrocarbon wax, maximum endothermic peak temperature 90°C) 8 parts by mass CI Pigment Blue 15:3 7 parts by weight The above materials were mixed in a Henschel mixer (FM-75, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s. -1After mixing for 5 minutes at 100°C, the mixture was kneaded in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation). The barrel temperature during kneading was set so that the outlet temperature of the kneaded product was 120°C. The outlet temperature of the kneaded product was directly measured using a handy type thermometer HA-200E manufactured by Anritsu Keiki Co., Ltd. The kneaded product obtained was cooled and coarsely crushed in a pin mill to a volume average particle size of 100 μm or less to obtain a coarsely crushed product.

[0055] <Manufacturing equipment 1> As the configuration of the grinding device, a mechanical grinder (Turbo Mill T250-CRS, manufactured by Turbo Kogyo Co., Ltd., rotor shape RS type) was modified to provide a feed mechanism that can supply raw materials by accelerated injection and can freely adjust the feed direction. In other words, it is possible to change the speed of accelerated injection when feeding raw materials and the angle θ between the direction of introduction of the material to be ground in the left diagram in Figure 2 and the tangent direction at the raw material inlet. The ratio Lj / Lr of the distance Lj from the end of the rotor on the supply port 101 side to the raw material supply port 201 to the total length Lr of the rotor in Figure 3 was set to 0.1. The configuration is shown in Table 1. The tooth configuration in Table 1 represents the shape of the rotor and stator. In the parallel teeth, the interval Da between the concave and convex parts of the rotor and stator was 1.3 mm, and the interval Db between the convex parts of the rotor and stator was 1.0 mm.

[0056] <Manufacturing equipment 2> The milling equipment was configured by modifying a mechanical mill (Turbo Mill T250-CRS, rotor shape RS type, manufactured by Turbo Kogyo Co., Ltd.) to supply raw materials by accelerated injection, and a supply mechanism was installed that could freely adjust the supply direction. The Lj / Lr ratio was set to 0.3. The configuration is shown in Table 1.

[0057] <Manufacturing equipment 3> The mechanical grinding machine (Turbo Mill T250-CRS, rotor shape RS type, manufactured by Turbo Kogyo Co., Ltd.) was used as the grinding device. The configuration is shown in Table 1.

[0058] <Manufacturing equipment 4> The milling equipment was a modified mechanical mill (Turbo Mill T250-CRS, rotor shape RS type, manufactured by Turbo Kogyo Co., Ltd.), with the same raw material supply method as the accelerated injection as in the manufacturing equipment 1, and with the rotor and stator teeth as shown in Figure 5 that mesh with each other with unevenness. The configuration is shown in Table 1.

[0059] [Table 1]

[0060] <Toner manufacturing method 1> In the configuration of device 1, θ is 55°, the feed of coarsely crushed material is 10 kg / h, the rotor speed is 170 m / s, the cold air temperature is -10°C, and the cold air volume is 8 m 3 The conditions for the accelerated injection were a nozzle diameter of 21.6 mm, pressure of 0.5 MPa, and flow rate of 0.5 L / min. The accelerated injection speed was 22.7 m / s.

[0061] <Production Examples of Toner Production Methods 2 to 12> In the toner production methods 2 to 12, the device configuration, the speed at which the material to be pulverized (coarsely pulverized material) is accelerated and sprayed, and θ were changed as shown in Table 2. The other operating conditions were the same as those in production method 1.

[0062] [Table 2]

[0063] <Example 1> The pulverizer was operated in the same manner as in toner production method 1, the average particle sizes D4 and D1 were measured, and D4 and the particle size distribution index D4 / D1 were evaluated.

[0064] [D4 Evaluation] The particle size of the toner particles after the pulverization process was evaluated according to the following criteria. A: D4 is less than 4.2μm (very good) B: D4 is 4.2μm or more and less than 4.4μm (Excellent) C: D4 is 4.4 μm or more and less than 4.6 μm (this is not a problem in the present invention) D:D4 is 4.6μm or more (not acceptable in this invention)

[0065] [D4 / D1 rating] The particle size distribution of the toner particles after pulverization was evaluated. The smaller the particle size distribution index D4 / D1, the sharper the distribution. As mentioned above, when the particle size distribution is sharp, there are fewer unnecessary particle size components to be removed in the classification process after the fine pulverization process. Therefore, it is possible to maintain high productivity. The evaluation criteria are as follows: A: D4 / D1 is less than 1.57 (excellent) B: D4 / D1 is 1.57 or more and less than 1.59 (excellent) C: D4 / D1 is 1.59 or more and less than 1.62 (this level is not problematic in the present invention) D: D4 / D1 is 1.62 or more (not acceptable in this invention)

[0066] <Examples 2 to 7 and Comparative Examples 1 to 5> Except for changing the production method, evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0067] [Table 3]

[0068] In Comparative Example 1, accelerated crushing was not performed for the supply of the material to be crushed, but the normal supply method was used. It is presumed that the evaluation of D4 was poor because the crushing effect due to collision during supply was not obtained.

[0069] In Comparative Example 2, the pulverizing teeth are meshing teeth. The accelerated and injected material to be pulverized collides directly with the rotor, but it is presumed that the poor evaluation of D4 was due to insufficient pulverization in the subsequent pulverization chamber.

[0070] Comparative Example 3 is an example in which the raw material supply position is shifted toward the discharge port. The accelerated injected material collides directly with the rotor, but it is presumed that the poor evaluation of D4 was due to insufficient pulverization in the subsequent pulverization chamber.

[0071] Comparative Example 4 is an example in which the accelerated jet speed of compressed air was increased to 51.9 m / sec. It is presumed that the collision energy due to the accelerated jet became excessive, which resulted in the generation of over-pulverized toner particles, resulting in a poor evaluation of D4 / D1.

[0072] Comparative Example 5 is an example in which the accelerated jet speed of compressed air was lowered to 8.8 m / sec. It is presumed that the collision energy sufficient for pulverization was not obtained, resulting in a poor evaluation of D4. [Explanation of symbols]

[0073] 101: supply port, 102: volute, 103: rotor, 104: stator, 105: rear chamber, 106: exhaust port, 107: central rotating shaft (rotating shaft), 108: cold air generator, 109: cold water supply port, 110: cold water exhaust port, 201: raw material supply port

Claims

1. A method for producing a toner, comprising a step of finely pulverizing a material to be pulverized, the material containing a binder resin and a colorant, by a pulverizing means, The crushing means is A powder supply mechanism for supplying the material to be pulverized; a stator having a plurality of protrusions and recesses on an inner circumferential surface; a rotor attached to a central rotating shaft and having a plurality of protrusions and recesses on an outer circumferential surface; A powder discharge port for discharging the finely pulverized material; having the stator contains the rotor, and the rotor is disposed so that a surface of the stator and a surface of the rotor face each other with a predetermined gap therebetween; The convex portions and concave portions present on the inner peripheral surface of the stator and the outer peripheral surface of the rotor are formed along the axial direction of the central rotation shaft, The protruding portion of the stator and the protruding portion of the rotor face each other with a gap of 0.8 mm or more and 1.4 mm or less between them, The material to be pulverized is accelerated and sprayed by the powder supply mechanism, and is supplied from a supply port so as to collide directly with the outer circumferential surface of the rotor. In a pulverization region formed by a gap between the stator and the rotor, the material is pulverized by the rotation of the rotor. When the rotor is divided into four equal parts along the central rotation axis, and each of the four equal parts is designated as a first region to a fourth region along the flow of the material to be crushed, (i) a position where the material to be pulverized is accelerated and jetted by the powder supply mechanism and collides with the rotor is a first region; (ii) the powder discharge port is provided downstream of the flow of the material to be ground; The accelerated air velocity when the material to be pulverized is accelerated and sprayed is 10 m / sec or more and 50 m / sec or less when passing through the supply port. A method for producing a toner comprising the steps of:

2. A toner manufacturing method as described in claim 1, wherein the powder supply mechanism supplies the material to be pulverized in a direction opposite to the direction of rotation of the rotor, and in a plane perpendicular to the rotation axis of the rotor, the angle θ between the introduction direction of the material to be pulverized and the powder supply mechanism and the stator is 20° or more and 80° or less.

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