Toner manufacturing method

Abstract

To suppress coalescence occurring among powder particles and the adhesion and fusion of the powder particles into an apparatus when forming the powder particles into spheres by heating to improve the productivity of toner.SOLUTION: A method for manufacturing toner comprises a heating step using a heat treatment device. The heat treatment device includes: (1) a treatment chamber having a cylindrical inner peripheral surface and capable of performing heat treatment by hot wind; (2) a plurality of powder particle supply means for supplying the powder particles to the treatment chamber; and (3) hot wind supply means for supplying the hot wind for performing heat treatments to the treatment chamber. Humidity control means for controlling the humidity of gas supplied to the hot wind supply means is connected to the hot wind supply means; the hot wind has a temperature of 100.0°C or more and 200.0°C or less; and the humidity of the hot wind is controlled by the humidity control means so as to form a relative humidity of 3.0% or more and 80.0% or less when supplied to the treatment chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a toner used in an image forming method such as electrophotography, electrostatic recording, electrostatic printing, or toner jet recording. [Background technology]

[0002] In electrophotographic imaging processes, toners are used to develop electrostatic images.

[0003] In recent years, as the quality and definition of output materials and images from copiers and printers have increased, the performance requirements for toners as developers have become increasingly strict, and toner particle diameters are now required to be small and have a sharp particle size distribution that does not contain coarse particles.

[0004] Furthermore, as media for copiers and printers needs to be compatible with a variety of materials other than ordinary paper, there is a demand for improved toner transferability, which has led to the need for spherical toner.

[0005] However, on the other hand, if the toner is made too spherical, the cleaning properties will be reduced, and therefore it is also necessary to control the sphericity of the toner and achieve both transferability and cleaning properties.

[0006] To meet such demands, one method for controlling the sphericity of toner is to melt the surface of the toner by heat treatment to make it spherical.

[0007] In devices that use heat treatment to make toner spherical, the toner is melted and spherical using hot air. Therefore, if the balance between the amount of hot air and the amount of toner supplied is lost, it may be impossible to obtain toner with the desired degree of sphericity, or the toner may melt too much and stick to the inside of the device, preventing stable operation of the device.

[0008] Furthermore, if the toner is not dispersed within the device, the toner particles melted by the hot air will adhere to each other and coalesce, resulting in a larger particle size and making it impossible to obtain toner with the desired particle size and sphericity.

[0009] To solve these problems, a method for producing toner has been proposed in which toner is heated and melted in a swirling flow of superheated steam, thereby obtaining toner with a desired degree of sphericity and a low degree of aggregation (see Patent Document 1). According to this proposal, the degree of aggregation of toner is reduced, the toner can be easily made spherical, production efficiency is high, and furthermore, a toner with excellent transferability is obtained.

[0010] However, when toner is heat-treated using this method, the high humidity of the superheated steam causes condensation to form immediately when it comes into contact with a cold object. This condensation can cause toner to adhere to the inside of the device, and the heated toner can fuse together inside the device. Also, with this method, the toner transport air is slow, so the toner does not disperse sufficiently inside the device, resulting in coalescence of particles and making it impossible to obtain spherical toner with the desired particle size.

[0011] Thus, in order to suppress toner fusion within the device, reduce coalescence of particles, and stably obtain toner with the desired particle size and sphericity when the toner is made spherical by heat treatment, there is room for improvement in the heat treatment device and the toner production method. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-129522 Summary of the Invention [Problem to be solved by the invention]

[0013] An object of the present invention is to improve toner productivity by suppressing coalescence between powder particles and adhesion or fusion of powder particles to the inside of an apparatus when powder particles containing a binder resin are made spherical by heat treatment. [Means for solving the problem]

[0014] The present invention provides a method for producing a toner, which includes a step of heat-treating powder particles containing a binder resin using a heat treatment device, The heat treatment device comprises: (1) a treatment chamber having a cylindrical inner surface in which heat treatment using hot air is performed; (2) a plurality of powder particle supply means for supplying the powder particles to the processing chamber; and (3) hot air supply means for supplying hot air for heat treatment into the treatment chamber; and The hot air supplying means is connected to a humidity adjusting means for adjusting the humidity of the gas supplied to the hot air supplying means, The hot air has a temperature of 100.0°C or higher and 200.0°C or lower, The method for producing toner is characterized in that the humidity of the hot air is adjusted by the humidity adjusting means so that the relative humidity of the hot air when supplied to the processing chamber is 3.0% or more and 80.0% or less. [Effects of the Invention]

[0015] According to the toner manufacturing method of the present invention, when powder particles containing a binder resin are sphericalized by heat treatment, by adjusting the temperature and humidity of the hot air, it is possible to suppress coalescence between the powder particles and adhesion or fusion of the powder particles to the inside of the device, thereby improving toner productivity. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a diagram showing an example of connections between a heat treatment device, a hot air supplying means, and a humidity adjusting means. [Figure 2] FIG. 1 is a schematic perspective view showing an example of a heat treatment apparatus. [Figure 3]FIG. 3 is a schematic cross-sectional view taken along the AA' plane in FIG. [Figure 4] A rotating member used in heat treatment equipment to swirl hot air in a spiral. [Figure 5] 1 is a schematic cross-sectional view of a divided powder supplying means used in a heat treatment device. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in more detail below with reference to preferred embodiments.

[0018] The present invention provides a method for producing a toner, which includes a step of heat-treating powder particles containing a binder resin using a heat treatment device, The heat treatment device comprises: (1) a treatment chamber having a cylindrical inner surface in which heat treatment using hot air is performed; (2) a plurality of powder particle supply means for supplying the powder particles to the processing chamber; and (3) hot air supply means for supplying hot air for heat treatment into the treatment chamber; and The hot air supplying means is connected to a humidity adjusting means for adjusting the humidity of the gas supplied to the hot air supplying means, The hot air has a temperature of 100.0°C or higher and 200.0°C or lower, The method for producing toner is characterized in that the humidity of the hot air is adjusted by the humidity adjusting means so that the relative humidity of the hot air when supplied to the processing chamber is 3.0% or more and 80.0% or less.

[0019] In this heat treatment, when powder particles containing a binder resin are spheroidized, the temperature and humidity of the hot air are adjusted to suppress coalescence between the powder particles and adhesion or fusion of the powder particles to the inside of the device, thereby improving toner productivity.

[0020] The mechanism is believed to be that the powder particles are heat-treated in hot air humidified to the humidity range of the present invention, whereby the electrostatic adhesion of the powder particles is alleviated during the heat treatment, thereby reducing adhesion between the powder particles and between the powder particles and the device, thereby suppressing toner fusion.

[0021] When the powder particles coalesce, the toner becomes irregular in shape, and therefore the temperature required to obtain the desired circularity becomes high, which also makes it more likely that fusion will occur within the device.

[0022] By reducing adhesion between powder particles, the toner produced by heat treatment does not contain coalesced particles, and it is possible to produce a toner with a sharp particle size distribution. In addition, since there is little adhesion or fusion to the equipment, toner productivity is improved and the time required to stop and clean the equipment for maintenance can be reduced.

[0023] The heat treatment apparatus used in the present invention will be outlined with reference to FIGS. 1, 2, 3, 4 and 5. FIG.

[0024] Figure 1 is a diagram showing an example of the connection between the heat treatment device, hot air supply means, and humidity adjustment means. In Figure 1, gas taken into the hot air blower is taken into the humidity adjustment means, and after the humidity is adjusted, it is supplied to the hot air supply means via the hot air blower and hot air heater. The humidity and temperature of the hot air are measured immediately after it passes through the hot air supply means. The humidity adjustment means only needs to be connected to the hot air supply means, and may be installed after the hot air blower or after the hot air heater in Figure 1.

[0025] The humidity adjusting means is not particularly limited, and a general humidity adjuster can be used. Examples include steam humidifiers, evaporative humidifiers, mist humidifiers, and hybrid humidifiers that combine these humidification methods. Specific examples include gas steam humidifiers, electric steam humidifiers, electrode steam humidifiers, evaporative mist humidifiers, vaporizing steam humidifiers, steam evaporation humidifiers, and centrifugal humidifiers.

[0026] Fig. 2 is a schematic perspective view of a heat treatment apparatus. Fig. 3 is a schematic cross-sectional view taken along the A-A' plane in Fig. 2. Fig. 4 shows a rotating member used in the heat treatment apparatus for spirally rotating hot air. Fig. 5 is a schematic cross-sectional view of a divided powder supplying means used in the heat treatment apparatus of the present invention.

[0027] As shown in FIG. 3, the heat treatment device has a cylindrical treatment chamber 1 in which the heat treatment of the toner powder particles is carried out.

[0028] In the heat treatment apparatus, the processing chamber may have any cylindrical shape.

[0029] Furthermore, the inside of the processing chamber is preferably cooled by a cooling jacket to prevent the powder particles from fusing together. Cooling water (preferably an antifreeze solution such as ethylene glycol) is preferably introduced into the cooling jacket, and the surface temperature of the cooling jacket is preferably 40°C or less.

[0030] In the heat treatment apparatus, powder particle supply means 2 for supplying powder particles to the treatment chamber is provided on the outer periphery of the treatment chamber. The powder particles may be accelerated and transported by injection air supplied from a high-pressure air supply nozzle (not shown) and supplied to the treatment chamber, or may be transported by suction with a blower without using injection air.

[0031] Hot air for heat-treating the supplied powder particles is supplied from hot air supply means 3. The hot air supplied into the treatment chamber has a temperature A (°C) of 100°C or more and 200°C or less at the outlet of hot air supply means 3. If the temperature at the outlet of the hot air supply means is within the above range, it is possible to uniformly spheroidize the powder particles while preventing the powder particles from fusing or coalescing due to excessive heating.

[0032] If the temperature (°C) is less than 100°C, the powder particles may not be sufficiently spherical. If the temperature exceeds 200°C, the processing temperature may be too high, causing the powder particles to fuse together inside the device.

[0033] The relationship between the hot air temperature A (℃) and the glass transition temperature Tg (℃) of the toner binder resin is as follows: Tg≦A When the hot air temperature and the glass transition temperature of the binder resin of the toner have the above-mentioned relationship, the toner particles are efficiently thermally spheroidized. When the hot air temperature is lower than the glass transition temperature of the binder resin of the toner, it tends to be difficult to spheroidize the toner particles.

[0034] The relative humidity of the hot air supplied to the processing chamber is adjusted by a humidity adjusting means to be 3.0% or more and 80.0% or less, and more preferably 4.0% or more and 75.0% or less.

[0035] By keeping the relative humidity of the hot air supplied to the processing chamber within the above range, the heat processing is performed in a state where the electrostatic adhesion of the powder particles being heat processed is relaxed, thereby reducing adhesion between the powder particles and between the powder particles and the device wall surface, and suppressing toner fusion.

[0036] By reducing adhesion between powder particles, the toner produced by heat treatment does not contain coalesced particles, and it is possible to produce a toner with a sharp particle size distribution. In addition, since there is little adhesion or fusion to the equipment, toner productivity is improved and the time required to stop and clean the equipment for maintenance can be reduced.

[0037] If the relative humidity of the hot air is less than 3.0%, the electrostatic adhesion of the powder particles being heat-treated cannot be reduced due to the low humidity of the hot air, and adhesion between the powder particles and the device wall may not be reduced. Also, if the relative humidity of the hot air exceeds 80.0%, condensation is likely to occur inside the device, and condensation may occur on the device wall, causing toner to adhere and develop into fusion.

[0038] In the present invention, the absolute moisture content of the hot air (g / m 3 ) is 25.0 g / m 3 More than 2500.0g / m 3It is preferable that the density is 590.0 g / m or less, and more preferably 590.0 g / m 3 More than 2200.0g / m 3 The following is the result.

[0039] By ensuring that the absolute moisture content of the hot air supplied to the treatment chamber is within the above-mentioned range, the electrostatic adhesion force of the powder particles being heat-treated is alleviated, reducing adhesion between the powder particles and between the powder particles and the equipment wall surface, and suppressing fusion within the equipment.

[0040] Furthermore, in the present invention, the volume of hot air supplied to the processing chamber is 20.0 m 3 / m or more 45.0m 3 / m or less, and more preferably 30.0 m 3 / m or more 45.0m 3 / m or less.

[0041] In the present invention, when the flow rate of the hot air supplied to the treatment chamber is within the above-mentioned range, the heat treatment is performed with humid hot air, which reduces the electrostatic adhesion of the powder particles. Furthermore, shear forces are generated by the hot air flow in the treatment chamber, and the powder particles are heat-treated in a more highly dispersed state. This reduces adhesion between powder particles and between powder particles and the equipment wall, thereby suppressing fusion within the equipment.

[0042] Furthermore, in the present invention, the speed of the conveying air per one of the plurality of powder particle supplying means is preferably 3.0 m / s or more and 12.0 m / s or less, more preferably 6.0 m / s or more and 9.0 m / s or less.

[0043] In the present invention, by keeping the speed of the conveying air within the above-mentioned range, the powder particles heat-treated in the device are highly dispersed by the shear force of the airflow. The powder particles are mixed with the hot air in a highly dispersed state in the device, preventing particle coalescence. If the speed is below the above-mentioned range, the powder particles may not be dispersed, which is undesirable. Furthermore, if the speed exceeds the above-mentioned range, the hot air may be cooled by the conveying air, which may prevent the desired spherical toner from being obtained, which is undesirable.

[0044] Furthermore, in the present invention, the relative humidity of the gas flowing through the heat treatment device is preferably 95.0% or less, and more preferably 90.0% or less. The gas flowing through the heat treatment device of the present invention is a mixture of all gases flowing through the treatment chamber, such as hot air, cold air, and carrier air introduced into the cylindrical treatment chamber, and secondary air taken into the treatment chamber together with the carrier air. The relative humidity of the gas flowing through the heat treatment device is measured by a hygrometer installed in the recovery means 6 at the lower end of the treatment chamber in Figures 2 and 3. By keeping the relative humidity of the gas flowing through the heat treatment device within the above range, condensation within the device is prevented and fusion of powder particles within the device is reduced.

[0045] The heat-treated powder particles are cooled by cold air supplied from cold air supply means 4. The temperature (°C) of the air supplied from cold air supply means 4 is preferably −20°C or higher and 30°C or lower. If the temperature of the cold air is within the above range, the powder particles can be cooled efficiently, and fusion and coalescence of the powder particles can be prevented without impeding the uniform spheroidization of the powder particles.

[0046] The flow of the powder particles supplied to the processing chamber is regulated by a regulating means 5 provided in the processing chamber for regulating the flow of powder particles. Therefore, the powder particles supplied to the processing chamber are heat-treated while swirling within the processing chamber, and then cooled.

[0047] Next, the cooled powder particles are collected by the collecting means 6 located at the bottom end of the processing chamber. A blower (not shown) is provided ahead of the collecting means, and the powder particles are sucked and transported by the blower.

[0048] The regulating means 5 for regulating the flow of powder particles used in the heat treatment apparatus of the present invention is a columnar member with a circular cross section that is disposed on the central axis of the treatment chamber so as to protrude from the lower end to the upper end of the treatment chamber. Because the regulating means 5 for regulating the flow of powder particles is located on the central axis of the treatment chamber, the powder particles supplied to the treatment chamber flow while swirling inside the cylindrical treatment chamber.

[0049] The columnar member is also provided with a substantially conical distribution member 7 at the center of its upper end for distributing the supplied hot air in the circumferential direction. The columnar member is further provided with a swirling member 8, as shown in Figure 4, for swirling the distributed hot air in a spiral shape within the processing chamber.

[0050] By adopting such a configuration for the hot air supplying section of the heat treatment apparatus of the present invention, the hot air supplied from the hot air supplying means flows while swirling uniformly inside the cylindrical treatment chamber.

[0051] Therefore, the powder particles supplied into the processing chamber are subjected to centrifugal force by the swirling flow during heat treatment, which results in fewer collisions between the powder particles and less coalescence of the powder particles during heat treatment.

[0052] It is preferable to provide a cooling jacket for the columnar member to prevent the powder particles from fusing together. Furthermore, it is preferable to introduce cooling water (preferably an antifreeze solution such as ethylene glycol) into the cooling jacket, and it is preferable that the surface temperature of the cooling jacket is 40°C or less.

[0053] The powder particle supplying means 2 of the heat treatment apparatus of the present invention is provided so that the swirling direction of the supplied powder particles and the swirling direction of the hot air are the same.

[0054] The powder particles supplied to the treatment chamber and the humid hot air swirl in the same direction, preventing turbulence within the treatment chamber. This reduces collisions between powder particles, while also ensuring that moisture is uniformly transferred from the hot air to the powder particles during heat treatment. This reduces the electrostatic adhesion of particles, reducing particle coalescence and adhesion within the equipment, and reducing fusion within the equipment.

[0055] Furthermore, the recovery means 6 of the heat treatment device is provided on the outer periphery of the treatment chamber so as to maintain the swirling direction of the swirling powder particles. This maintains the swirling flow within the device, maintains the centrifugal force acting on the powder particles, and reduces adhesion and fusion of the powder particles to the regulating means 5 that regulates the flow of the powder particles. Furthermore, with this configuration, the introduced hot air, cold air, transport air, etc. are mixed in the recovery means, so the humidity is kept constant.

[0056] It is preferable that the cold air supply means 4 of the heat treatment apparatus of the present invention are provided in multiple locations on the outer periphery of the treatment chamber, and that the cold air supplied from the cold air supply means is supplied along the inner periphery of the treatment chamber in the same direction as the swirling direction of the hot air.

[0057] In the heat treatment apparatus of the present invention, the cold air supplied from the cold air supply means is configured to be supplied horizontally and tangentially from the outer periphery of the apparatus to the circumferential surface inside the treatment chamber, thereby preventing adhesion of powder particles to the wall surface of the treatment chamber.

[0058] Furthermore, since the swirling direction of the cold air supplied from the cold air supplying means is the same as the swirling direction of the hot air, no turbulence occurs within the processing chamber, and coalescence of powder particles can be prevented.

[0059] Furthermore, the supplied cold air is preferably divided into multiple parts at the horizontal cross section of the device, more preferably divided into eight parts. This is to make it easier to uniformly control the air flow within the device, and the amount of cold air in each of the eight divided introduction paths can be controlled independently. This further strengthens the swirling flow within the device, applying a strong centrifugal force to the powder particles and improving their dispersibility.

[0060] The powder particle supplying means 2 of the heat treatment apparatus of the present invention is preferably provided so that the supplied powder particles are supplied along the inner circumferential surface of the treatment chamber, and a plurality of such means are preferably provided in the same circumferential direction.

[0061] In the heat treatment apparatus of the present invention, the powder particles supplied from the powder supply means 2 are supplied from the outer periphery of the apparatus to the circumferential surface of the treatment chamber in a horizontal and tangential direction. Therefore, a strong centrifugal force is applied to the powder particles supplied into the treatment chamber, improving the dispersibility of the powder particles.

[0062] In the heat treatment device of the present invention, the swirling directions of the powder particles supplied from the powder supply means, the cold air supplied from the cold air supply means, and the humid hot air supplied from the hot air supply means are all the same. This prevents turbulence within the treatment chamber, strengthens the swirling flow within the device, and applies a strong centrifugal force to the powder particles while uniformly transferring humidity from the hot air to the powder particles. As a result, the electrostatic adhesion of the powder particles is reduced, further improving the dispersibility of the powder particles and resulting in a toner with fewer coalesced particles. Furthermore, because turbulence does not occur within the device, there is less adhesion of powder particles to the device's inner walls, reducing fusion within the device.

[0063] Furthermore, in the heat treatment apparatus of the present invention, a plurality of powder particle supply means 2 are provided in the same circumferential direction. As shown in Figure 5, the greater the number of divisions of the powder particle supply means, the lower the dust concentration of the powder particles immediately after they are introduced into the treatment chamber, and the more uniform the humidity transferred from the hot air to the powder particles becomes. In other words, the greater the number of divisions of the powder particle supply means, the more electrostatic adhesion force is weakened, and coalescence and fusion are suppressed.

[0064] Next, a procedure for producing toner using the heat treatment apparatus of the present invention will be described.

[0065] First, in the raw material mixing process, predetermined amounts of at least resin and colorant are weighed and mixed as toner raw materials. Examples of mixing devices include a Henschel mixer (manufactured by Nippon Coke Company), a Supermixer (manufactured by Kawata Corporation), a Ribocone (manufactured by Okawara Manufacturing Co., Ltd.), a Nauta mixer, a Turbulizer, and a Cyclomix (manufactured by Hosokawa Micron Corporation), a Spiral Pin Mixer (manufactured by Pacific Machinery Works, Ltd.), and a Loedige mixer (manufactured by Matsubo Corporation).

[0066] Furthermore, the mixed toner raw materials are melted and kneaded in a melt-kneading step to melt the resins and disperse the colorant therein. Examples of kneading devices include a TEM extruder (manufactured by Toshiba Machine Co., Ltd.), a TEX twin-screw kneader (manufactured by The Japan Steel Works, Ltd.), a PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.), and a Kneedex (manufactured by Nippon Coke Company), but continuous kneaders such as single-screw or twin-screw extruders are preferred over batch kneaders because of their advantages such as the ability to perform continuous production.

[0067] Furthermore, the colored resin composition obtained by melt-kneading the toner raw materials is rolled with a two-roll mill or the like after melt-kneading, and then cooled through a cooling step in which the composition is cooled with water or the like.

[0068] The cooled colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step, in which the pulverization is first coarsely pulverized using a crusher, hammer mill, feather mill, or the like, and then finely pulverized using a Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), a Super Rotor (manufactured by Nisshin Engineering, Inc.), or the like, to obtain toner particles.

[0069] The resulting toner particles are classified into powder particles having the desired particle size in a classification process using a classifier such as Turboplex, Faculty, TSP Separator, or TTSP Separator (manufactured by Hosokawa Micron Corporation); or Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.).

[0070] Subsequently, the obtained powder particles for toner are subjected to a spheronization treatment in a heat treatment step using the heat treatment device of the present invention.

[0071] In the toner manufacturing method of the present invention, inorganic fine particles, etc. may be added to the obtained toner powder particles before the heat treatment step, as needed. The method of adding inorganic fine particles, etc. to toner powder particles involves blending the toner powder particles with predetermined amounts of various known external additives, and stirring and mixing them using a high-speed mixer that applies shear force to powders, such as a Henschel mixer, Mechano Hybrid (manufactured by Nippon Coke Company), Super Mixer, or Nobilta (manufactured by Hosokawa Micron Corporation).

[0072] In the toner manufacturing method of the present invention, inorganic fine powder is added to the toner powder particles before the heat treatment step, which gives the toner powder particles fluidity and allows the toner powder particles introduced into the treatment chamber to be more uniformly dispersed and come into contact with the hot air, thereby producing a toner with excellent uniformity.

[0073] In the toner manufacturing method of the present invention, if coarse particles are present after the heat treatment, a step of removing the coarse particles by classification may be included, if necessary. Examples of classifiers for removing coarse particles include Turboplex, TSP Separator, TTSP Separator (manufactured by Hosokawa Micron Corporation), and Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.).

[0074] Furthermore, after the heat treatment, if necessary, a sieving machine such as Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonaseave, Gyroshifter (manufactured by Tokuju Kogyosho Co., Ltd.); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); or Hi-Bolter (manufactured by Toyo Hitec Co., Ltd.) may be used to sift out coarse particles, etc.

[0075] The heat treatment step of the present invention may be carried out after the above-mentioned fine pulverization or after classification.

[0076] Next, the toner constituent materials used in the toner manufacturing method of the present invention will be described.

[0077] <Binder resin> As the binder resin used in the toner, a general resin can be used, and examples thereof include polyester, styrene-acrylic acid copolymer, polyolefin resin, vinyl resin, fluororesin, phenol resin, silicone resin, and epoxy resin. Among these, amorphous polyester is preferably used from the viewpoint of improving low-temperature fixability, and low-molecular-weight polyester and high-molecular-weight polyester may be used in combination from the viewpoint of achieving both low-temperature fixability and hot offset resistance. Furthermore, crystalline polyester may be used as a plasticizer from the viewpoint of further improving low-temperature fixability and blocking resistance during storage.

[0078] <Release agent> Examples of the release agent used in the toner include the following.

[0079] Low molecular weight polyolefins, silicone wax, fatty acid amides, ester waxes, carnauba wax, hydrocarbon waxes, etc. These release agents may be used alone or in combination of two or more.

[0080] The release agent may be mixed with the synthetic raw materials of the binder resin when synthesizing the binder resin used in producing toner particles, or may be added in the raw material mixing step during toner production. The content of the release agent in the toner is preferably 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the binder resin.

[0081] <Inorganic fine particles> As mentioned above, in the toner manufacturing method according to the present invention, inorganic fine particles are preferably added to the toner particles before the heat treatment step. The inorganic fine particles are mixed with the toner particles before the heat treatment as an external additive. The inorganic fine particles are preferably fine particles of silica, titanium oxide, aluminum oxide, or strontium titanate. The inorganic fine particles are preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil, or a mixture thereof.

[0082] The number-average particle size of the inorganic fine particles is preferably 10 nm or more and 300 nm or less. In order to simultaneously improve fluidity and stabilize durability, multiple types of inorganic fine particles having number-average particle sizes within the above ranges may be used in combination.

[0083] The content of the inorganic fine particles is preferably 0.01 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner particles.

[0084] <Coloring agent> Examples of colorants used in toner include the following:

[0085] That is, examples of colorants include known organic pigments or oil-based dyes, carbon black, and magnetic materials.

[0086] Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

[0087] 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.

[0088] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

[0089] 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.

[0090] The colorants can be used alone or in combination of two or more.

[0091] Next, methods for measuring various physical properties of toner particles will be described below.

[0092] <Method for measuring weight average particle size (D4) of toner particles> The weight average particle diameter (D4) of the toner particles can be calculated by measuring with an effective number of measurement channels of 25,000 using the following device and software, and analyzing the measurement data. A precision particle size distribution analyzer using the electrical resistance method with a 50 μm aperture tube, the Coulter Counter Multisizer 3 (registered trademark, manufactured by Beckman Coulter, Inc.) The dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) that comes with the above instrument is used to set measurement conditions and analyze measurement data. The aqueous 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, such as "ISOTON II" (manufactured by Beckman Coulter).

[0093] Before carrying out the measurement and analysis, the dedicated software is set up as follows.

[0094] In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count in 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. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement."

[0095] In the dedicated software's "Pulse to particle size conversion setting screen," 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.

[0096] The specific measurement method is as follows.

[0097] (1) Pour approximately 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made specifically 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 any dirt or air bubbles from inside the aperture tube.

[0098] (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% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water is added as a dispersant.

[0099] (3) Prepare an ultrasonic disperser "Ultrasonic Dispension System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.) equipped with two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees, and with an electrical output of 120 W. Place a predetermined amount of ion-exchanged water in a water tank equipped with this ultrasonic disperser, and add approximately 2 ml of the Contaminon N to this water tank.

[0100] (4) Set the beaker (2) in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized.

[0101] (5) While the electrolyte solution in the beaker in (4) is irradiated with ultrasonic waves, approximately 10 mg of toner is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C.

[0102] (6) Using a pipette, add the electrolyte solution (5) containing the dispersed toner to the round-bottom beaker (1) placed in the sample stand, and adjust the measurement concentration to approximately 5%. Then, measure the particle count until it reaches 50,000 particles.

[0103] (7) The measurement data is analyzed using the dedicated software provided 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).

[0104] <Method for measuring average circularity> The average circularity of the toner particles can be measured using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used during the calibration process.

[0105] The specific measurement method is as follows.

[0106] First, about 20 ml of ion-exchanged water, from which impurities such as solids have been removed, is placed in a glass container, and about 0.2 ml of a solution prepared by diluting Contaminon N (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) approximately three times by mass with ion-exchanged water is added as a dispersant.

[0107] Approximately 0.02 g of the sample to be measured was then added and dispersed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. The dispersion was then cooled appropriately so that its temperature was between 10°C and 40°C. A tabletop ultrasonic cleaner disperser (VS-150, manufactured by Vervoclear) with an oscillation frequency of 50 kHz and an electrical output of 150 W was used as the ultrasonic disperser. A predetermined amount of ion-exchanged water was placed in a water tank, and approximately 2 ml of Contaminon N was added to the tank.

[0108] The measurement was performed using the flow particle image analyzer equipped with a standard objective lens (10x magnification), and a particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the procedure described above was introduced into the flow particle image analyzer, and 3,000 toner particles were measured in HPF measurement mode and total count mode. The binarization threshold for particle analysis was set to 85%, and the analyzed particle size was limited to a circle-equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles was determined.

[0109] Before starting the measurement, automatic focus adjustment is performed using standard latex particles. Standard latex particles are used (Duke Scientific's "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" diluted with ion-exchanged water). After that, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0110] In the examples of the present application, a flow-type particle image analyzer was used that had been calibrated by Sysmex Corporation and had a calibration certificate issued by Sysmex Corporation. Measurements were carried out under the same measurement and analysis conditions as when the calibration certificate was issued, except that the particle size to be analyzed was limited to a circle-equivalent diameter of 1.985 μm or more and less than 39.69 μm.

[0111] <Measurement of glass transition temperature (Tg) of toner> The glass transition temperature is measured using a differential scanning calorimeter "Q2000" (manufactured by TA Instruments) in accordance with ASTM D3418-82. The melting points of indium and zinc are used to correct the temperature of the detector, and the heat of fusion of indium is used to correct the heat quantity.

[0112] Specifically, about 3 mg of resin or toner particles are precisely weighed and placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is carried out under the following conditions. Heating rate: 10℃ / min Measurement start temperature: 30℃ Measurement end temperature: 180℃

[0113] First, measurements are taken at a heating rate of 10°C / min within the measurement range of 30 to 180°C. The temperature is raised to 180°C once and held there for 10 minutes, then lowered to 30°C, and then raised again. During this second heating process, the specific heat change is obtained within the temperature range of 30 to 100°C. The point at which the line midpoint between the baselines before and after the specific heat change appears and the differential thermal curve intersects is taken as the glass transition temperature (Tg). [Example]

[0114] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, parts are by weight unless otherwise specified.

[0115] <Production example of amorphous polyester L> Polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane: 72.0 parts (0.200 mole parts; 100.0 mole % based on the total number of moles of polyhydric alcohol) Terephthalic acid: 28.0 parts (0.169 moles; 96.0 mole % based on the total number of moles of polycarboxylic acids) 0.5 parts tin 2-ethylhexanoate (esterification catalyst)

[0116] The above materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. After the atmosphere in the flask was replaced with nitrogen gas, the temperature was gradually raised with stirring, and the mixture was allowed to react at 200°C for 4 hours with stirring.

[0117] The pressure inside the reactor was then reduced to 8.3 kPa and maintained at this temperature for 1 hour, after which the reactor was cooled to 180°C and returned to atmospheric pressure. Trimellitic anhydride: 1.3 parts (0.007 moles; 4.0 mole% based on the total number of moles of polycarboxylic acids) tert-butylcatechol (polymerization inhibitor): 0.1 parts

[0118] The above materials were then added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 1 hour while maintaining the temperature at 180°C. After confirming that the softening point measured in accordance with ASTM D36-86 reached 90°C, the temperature was reduced to stop the reaction, and amorphous polyester L was obtained.

[0119] <Production example of amorphous polyester H> Polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane: 72.3 parts (0.200 moles; 100.0 mole % based on the total number of moles of polyhydric alcohol) Terephthalic acid: 18.3 parts (0.110 moles; 65.0 mole % based on the total number of moles of polycarboxylic acids) Fumaric acid: 2.9 parts (0.025 moles; 15.0 mole % based on the total number of moles of polycarboxylic acids) 0.5 parts tin 2-ethylhexanoate (esterification catalyst)

[0120] The above materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. After the atmosphere in the flask was replaced with nitrogen gas, the temperature was gradually raised with stirring, and the mixture was allowed to react at 200°C for 2 hours with stirring.

[0121] The pressure inside the reactor was then reduced to 8.3 kPa and maintained for 1 hour, after which the reactor was cooled to 180 and returned to atmospheric pressure. Trimellitic anhydride: 6.5 parts (0.034 moles; 20.0 mole % based on the total number of moles of polycarboxylic acids) tert-butylcatechol (polymerization inhibitor): 0.1 parts

[0122] The above materials were then added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 160°C. After confirming that the softening point measured in accordance with ASTM D36-86 reached 137°C, the temperature was reduced to stop the reaction, and amorphous polyester H was obtained.

[0123] <Crystalline polyester> 1,6-Hexanediol: 34.5 parts (0.29 moles; 100.0 mole% based on the total number of moles of polyhydric alcohols) Dodecanedioic acid: 65.5 parts (0.28 moles; 100.0 mole % based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate: 0.5 parts

[0124] The above materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. After the atmosphere in the flask was replaced with nitrogen gas, the temperature was gradually raised with stirring, and the mixture was allowed to react for 3 hours at 140°C with stirring.

[0125] Next, the above materials were added, the pressure inside 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.

[0126] Furthermore, the pressure in the reaction vessel was gradually released to return to normal pressure, and then 7.0 mol % of stearic acid was added relative to 100.0 mol % of the raw material monomer, and the mixture was reacted at 200° C. under normal pressure for 2 hours.

[0127] 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.

[0128] <Example of manufacturing powder particles for toner> Amorphous polyester L 70 parts Amorphous polyester H 30 parts Crystalline polyester 5 parts Fischer-Tropsch wax (maximum endothermic peak temperature 90°C) 6 parts CI Pigment Blue 15:3 7 parts

[0129] The ingredients of the above formulation were mixed in a Henschel mixer FM-75 (manufactured by Nippon Coke Company), and then kneaded in a twin-screw kneader PCM-30 (manufactured by Ikegai Iron Works Co., Ltd.) set at 120°C. The resulting kneaded mixture was cooled and coarsely pulverized to 1 mm or less using a hammer mill to obtain coarsely pulverized toner. The resulting coarsely pulverized toner was then pulverized in a mechanical pulverizer T-250 (manufactured by Turbo Kogyo Co., Ltd.) to obtain toner particles. The resulting toner particles were then classified using a Faculty (manufactured by Hosokawa Micron Corporation).

[0130] The toner powder particles obtained at this time had a glass transition temperature of 58° C., a weight average particle size (D4) of 5.73 μm, and an average circularity of 0.952.

[0131] Hereinafter, this will be referred to as toner powder particles A1.

[0132] Furthermore, the following materials were added to a Henschel mixer (FM-75 model, manufactured by Nippon Coke Co.), and mixed for 3 minutes at a rotating blade peripheral speed of 50.0 m / sec to obtain toner powder particles B1 in which silica and strontium titanate were attached to the surface of toner powder particles A. Toner powder particles A1: 100 parts Silica fine particles (number average particle size 100 nm): 3 parts Strontium titanate fine particles (number average particle size 30 nm) 0.5 parts

[0133] Example 1 In this example, a humidity adjusting means was connected to the hot air supplying means, the heat treatment device shown in Figures 2 and 3 and the rotating member shown in Figure 4 were used, the raw material supplying means was divided into eight parts as shown in Figure 5, and toner powder particles B1 were heat treated under the following operating conditions.

[0134] Toner powder particle B1 supply rate: 200 kg / hr ·Hot air temperature: 160.0℃ ·Hot air volume: 35.0m 3 / min Hot air relative humidity: 67.3% Absolute moisture content of hot air: 2085.0g / m 3 Conveying air speed per powder particle supply means: 8.0m / s Relative humidity of the gas flowing through the heat treatment equipment: 90%

[0135] Other operating conditions are: cold air temperature -5°C, cold air from the first and second stages 6.0 m 3 / min divided into 8, each 0.75m 3 / min. The third stage of cold air was supplied to the treatment chamber at a flow rate of 4.2 m 3 / min is supplied in three parts, each 1.4m 3 / min of cold air was supplied to the treatment chamber.

[0136] The heat-treated particles obtained had a weight-average particle size (D4) of 5.73 μm and an average circularity of 0.968.

[0137] The heat-treated particles thus obtained were evaluated for their aggregability as follows.

[0138] <Evaluation of powder particle cohesion> The difference between the weight average particle size of the obtained heat-treated particles and the weight average particle size of the powder particles B1 for toner before heat treatment (ΔD4 = weight average particle size of the heat-treated particles - weight average particle size of the powder particles B1 for toner) was calculated and evaluated according to the following criteria. A: ΔD4<0.10 B: 0.10≦ΔD4<0.20 C: 0.20≦ΔD4<0.30 D: 0.30≦ΔD4 After further operation under the same conditions for 1 hour, fusion within the device was confirmed and evaluated as follows.

[0139] <Evaluation of in-device fusion> The scope part of an industrial videoscope "IPLEX NX" (manufactured by Olympus Corporation) was inserted through an inspection hatch (not shown) on the side of the heat treatment device to check the fusion state inside the device and judge it according to the following criteria. A: No fusion is observed at all. B: Slight fusion is observed, but at a level that does not interfere with operation. C: Welding is observed, but at a level that does not interfere with operation. D: Fusion is observed, and operation must be stopped and cleaning is required.

[0140] The results of the above evaluations are shown in Table 2.

[0141] [Examples 2 to 23, Comparative Examples 1 to 5] Toner powder particles B1 were heat-treated under the same operating conditions as in Example 1, except that the operating conditions of the heat treatment device were changed to those shown in Table 1. Furthermore, the weight-average particle size and average circularity of the obtained heat-treated particles were measured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0142] Comparative Example 6 Toner powder particles B1 were heat-treated under the same conditions as in Example 1, except that no humidity adjusting means was connected to the hot air supplying means and the conditions were changed to those shown in Table 1. Furthermore, the weight-average particle size and average circularity of the obtained heat-treated particles were measured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0143] [Table 1]

[0144] [Table 2] [Explanation of symbols]

[0145] 1. Cylindrical processing chamber where heat treatment takes place 2 Powder particle supply means 3 Hot air supply means 4 Cold air supply means 4-1 First stage cold air supply means 4-2 Second stage cold air supply means 4-3 Third stage cool air supply means 5. Restricting means for restricting the flow of powder particles 6. Recovery Methods 7. Approximately conical distribution member 8 Swivel member 9 Blade of pivoting member 10 Powder particles

Claims

1. A method for producing a toner, comprising a step of heat-treating powder particles containing a binder resin using a heat treatment device, The heat treatment device comprises: (1) a treatment chamber having a cylindrical inner circumferential surface in which heat treatment using hot air is performed; (2) a plurality of powder particle supply means for supplying the powder particles to the processing chamber; and (3) hot air supply means for supplying hot air for heat treatment into the treatment chamber; and The hot air supplying means is connected to a humidity adjusting means for adjusting the humidity of the gas supplied to the hot air supplying means, The hot air has a temperature of 100.0°C or higher and 200.0°C or lower, The method for producing toner, wherein the humidity of the hot air is adjusted by the humidity adjusting means so that the relative humidity of the hot air when supplied to the processing chamber is 3.0% or more and 80.0% or less.

2. 2. The method for producing toner according to claim 1, wherein the hot air has a relative humidity of 4.0% or more and 75.0% or less when supplied to the processing chamber.

3. The absolute moisture content of the hot air (g / m ３ ) is 25.0 g / m ３ 2500.0g / m or more ３ 3. The method for producing a toner according to claim 1, wherein the following is true:

4. The volume of hot air supplied to the treatment chamber is 20.0 m ３ / m or more 45.0m ３ The method for producing a toner according to claim 1 , wherein the toner particle size is 1 / m or less.

5. 5. The method for producing toner according to claim 1, wherein a speed of the transport air per one of the plurality of powder particle supplying means is 3.0 m / s or more and 12.0 m / s or less.

6. 6. The method for producing a toner according to claim 1, wherein the relative humidity of the gas flowing through the heat treatment device is 95.0% or less.

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