JP2001255696A - Electrostatic charge image developing toner and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner which does not require pulverization or classification processes, which shows sufficiently sharp distribution of the grain size without containing coarse particles and which has excellent transfer property so that a good image can be stably obtained, and to provide a method of manufacturing the toner. SOLUTION: In the electrostatic charge image developing toner manufacturing method comprising a drying process, a loop type pneumatic conveying dryer is used in the drying process in which air flow 7 whose temperature is >=70 deg.C and line velocity is >=30 m/s is supplied to the loop 1 of the pneumatic conveying dryer and the air flow temperature at the toner collecting part 5 of the dryer is controlled to <=60 deg.C. Preferably, by supplying second air flow whose temperature is <=50 deg.C through a second air flow supply port 8 disposed between the loop part 1 and the toner collecting part 5, the temperature of the air flow between the second air flow supply port 8 and the toner collecting part 5 is controlled to <=60 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image, which is used in electrophotography or electrostatic recording and contains a binder resin and a colorant, and a method for producing the same.

[0002]

2. Description of the Related Art A toner for developing an electrostatic image (hereinafter sometimes simply referred to as "toner") is composed of at least a binder resin and a coloring agent. Various methods have been proposed as a method for producing. 2. Description of the Related Art Heretofore, there have been known several methods for producing an electrostatic image developing toner for developing an electrostatic latent image formed by an electrophotographic method or an electrostatic recording method. As one method, there is a method of producing polymer fine particles by making a polymer prepared by a polymerization reaction in advance into fine particles. Among them, the melt-kneading pulverization method is a method of obtaining polymer fine particles by pulverizing a polymer which has been coarsely pulverized in advance using a fine pulverizer such as a mechanical rotary type or a jet type, and then classifying it, and is currently the most frequently used method. A method for producing a toner for developing an electrostatic image. However, the polymer fine particles obtained by this method are irregular, have a nonuniform particle size, and have disadvantages such as requiring a classification step to sharpen the particle size distribution.

[0003] As a method of improving these disadvantages, for example, using a monomer as a starting material, for example, JP-B-36-1023
There is known a method for directly producing polymer fine particles by a polymerization reaction such as a suspension polymerization method, an emulsion polymerization method, a seed polymerization method, or a dispersion polymerization method as disclosed in JP-A No. 1 (1993) -107. Further, as disclosed in Japanese Patent Publication No. 35-7924, a method of forming particles by spraying a polymer solution previously dissolved in a solvent into a mist,
As disclosed in US Pat. No. -9485, a poor solvent is added to a polymer solution previously dissolved in a solvent,
Alternatively, a method of precipitating polymer fine particles by cooling a polymer solution previously dissolved in a solvent by heating is also known. Further, as disclosed in Japanese Patent Application Laid-Open No. 50-120632 and the like,
A method of obtaining polymer fine particles by dispersing in a medium heated to a temperature higher than the melting point and cooling the dispersion is also known.

Further, JP-B-38-2095, JP-B-61-28688, JP-A-63-25664, JP-A-7-152202, and JP-A-9-15
As disclosed in JP-A-902, for example, a polymer solution (toner composition mixture) previously dissolved in a solvent is dispersed and suspended in an aqueous medium, and the solvent is removed by heating or reducing the pressure to thereby remove the solvent. There is a method of making particles.
In this method, since a monomer and a surfactant are not used, there is no need to remove a residual monomer and a surfactant, and it is easy to internally add an insoluble material such as a coloring agent, a charge controlling agent, and a release agent. It has the features that it is not necessary to consider the optimal conditions for particle formation even if the material composition is changed, that the particle size distribution is relatively sharp, that the aqueous medium is easy to clean, It is considered a method suitable for industrialization.

However, regardless of whether a monomer is used as a starting material or a polymer is used as a starting material, in a method in which toner particles are granulated by a wet method and dried to obtain toner particles, blocking of the toner particles occurs during drying. However, even if the particle size distribution was sufficiently sharp before drying, coarse particles were generated and the particle size distribution was actually deteriorated. The coarse particles of the electrostatic image developing toner are as follows:
At the time of transfer, the transferability to the recording material is poor, and it remains untransferred toner on the photoreceptor after the transfer, resulting in waste toner. On the other hand, if the particle size distribution of the electrostatic image developing toner becomes sharp, the following effects are obtained. (1) Transfer efficiency is increased. (2) Cleaning failure is eliminated.
(3) Charging becomes sharp. (4) It is difficult to selectively develop.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention does not require crushing and classification, the particle size distribution is sufficiently sharp, and there are no coarse particles, further excellent transferability, and a toner for electrostatic image development capable of stably obtaining a good image and It is an object of the present invention to provide a manufacturing method thereof.

[0007]

Means for solving the above problems are as follows. <1> In a method for producing a toner for developing an electrostatic image having a drying step, a loop type flash dryer is used in the drying step, and the temperature of the loop portion of the flash dryer is 70 ° C. or higher; And supply an airflow having a linear velocity of 30 m / s or more,
The temperature of the air flow in the toner recovery section of the flash dryer is 60
C. or lower, which is a method for producing an electrostatic image developing toner. <2> An electrostatic image developing toner obtained by the method for producing an electrostatic image developing toner according to <1>.

[0008] Further, means for solving the above problems include:
It is as follows. <3> By supplying a second airflow having a temperature of 50 ° C. or less from a second airflow supply port provided between the loop portion and the toner collecting portion, the second airflow supply port is connected to the second airflow supply port. The method for producing a toner for developing an electrostatic image according to <1>, wherein the temperature of the airflow between the toner collection unit and the toner collection unit is set to 60 ° C. or lower. <4> a step of dissolving or dispersing the binder resin and the colorant in a solvent to obtain a toner composition mixture before the drying step, adding the toner composition mixture to an aqueous medium, and using an emulsifier The method for producing a toner for developing an electrostatic image according to the above <1> or <3>, comprising a step of obtaining a suspension by dispersing and suspending the mixture, and a step of removing a solvent from the suspension to obtain a toner dispersion. It is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. —Method for Producing Toner for Developing an Electrostatic Image— The method for producing the toner for developing an electrostatic image of the present invention includes at least a drying step, and further includes other steps as necessary. In the present invention, when a polysynthetic monomer (monomer) is used as a starting material, before the drying step,
It is preferable to have a mixing step, a dispersion suspension step, a polymerization step, and a washing dehydration step. When a binder resin (polymer) is used as a starting material, the mixing step is performed before the drying step.
It is preferable to have a dispersion suspension step, a solvent removal step, and a washing dehydration step.

[Mixing Step] In the mixing step, a mixed solution containing a binder resin or a polymerizable monomer and a colorant (hereinafter, referred to as a mixed solution)
This is referred to as “toner composition mixture”. ) Is prepared, and if necessary, these components are dissolved or dispersed in a solvent to prepare a toner composition mixed solution. Further, if necessary, the toner composition mixture may optionally contain other components in addition to these components, such as a release agent and a charge control agent which are usually added to the toner particles. The toner composition mixture may be a solution obtained by previously kneading a colorant, a release agent, a charge control agent, and the like with a binder resin, and dissolving or dispersing the same in a solvent. A colorant, a release agent, a charge control agent, and the like may be dispersed in the solvent or the polymerizable monomer using a medium-containing disperser such as a ball mill or a sand mill, or a high-pressure disperser. In this mixing step, mixing may be performed by any method as long as the colorant is dispersed in the solvent in which the binder resin is dissolved or in the polymerizable monomer.

(Binder Resin / Polymerizable Monomer) The binder resin and the polymerizable monomer used in the mixing step are not particularly limited, and any known one can be used. . Specific examples of the polymerizable monomer include styrenes such as styrene, parachlorostyrene and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, acrylic Esters having an unsaturated bond such as 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, and 2-ethylhexyl methacrylate; having an unsaturated bond such as acrylonitrile and methacrylonitrile Nitriles; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; and olefins such as ethylene, propylene and butadiene.

Examples of the binder resin include a polymer or a copolymer using the same, a mixture thereof, and the like, and further include an epoxy resin, a polyester resin, a polyurethane resin,
Non-vinyl condensation resins such as polyamide resins, cellulose resins, and polyether resins; mixtures of these condensation resins with the vinyl resins; grafts obtained by polymerizing vinyl monomers in the presence of these polymers Polymers. These binder resin and polymerizable monomer,
One type may be used alone, or two or more types may be used in combination.

When the polymerizable monomer is used, it is preferable to add a polymerization initiator, and a known polymerization initiator can be used. Specifically, 2,2′-Azobis (2,4-dimethyl)
lvaleronitrile), 2,2'-Azob
is (2-methylbutyronitril
e), 2,2'-Azobisisobutyroni
trile), 2,2′-Azobis (2,4-di)
methyl-4-methoxyvaleronit
ile) or an azo-based polymerization initiator such as methyl e.
thyl ketoneperoxide, Cumen
e hydro peroxide, Benzoyl
and peroxide-based polymerization initiators such as peroxide. These are used in an amount of 0.1 to 100 parts by weight of the polymerizable monomer.
It is used in an amount of 1 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

(Colorant) As the colorant used in the mixing step, for example, carbon black, chrome yellow, Hansa yellow, benzidine yellow, sllen yellow, quinoline yellow, permanent orange GR
T, pyrazolone orange, balkan orange, watch red, permanent red, brilliant carmine 3B, brilliant carmine 6B, Dupont oil red, villazolone red, lithol red, rhodamine B lake, lake red C, rose bengal, aniline blue, ultramarine Blue, calcoil blue, methylene blue chloride, phthalocyanine blue,
Examples include phthalocyanine green and malachite green oxalate.

(Other Components) In the mixing step, a magnetic substance, a charge controlling agent, a release agent, and the like can be contained as internal additives as the other components. As the magnetic material, ferrite, magnetite, reduced iron, cobalt,
Examples thereof include metals such as nickel and manganese or alloys thereof, and compounds containing these metals. Examples of the charge control agent include a quaternary ammonium salt compound, a boron salt compound, a nigrosine compound, aluminum, iron,
Known dyes such as a dye composed of a treatment body such as chromium, and a triphenylmethane-based pigment may be used.

Examples of the releasing agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicone resins which are softened by heating, olefin amide, erucamide, ricinoleamide, and the like.
Fatty acid amides such as stearic acid amide, carnauba wax, rice wax, candelilla wax, vegetable wax such as wood wax, jojoba oil, animal wax such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline Mineral and petroleum waxes such as wax and Fischer-Tropsch wax, and modified products thereof.

As the solvent used in the mixing step,
Ester solvents such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; ether solvents such as diethyl ether, dibutyl ether and dihexyl ether; ketone solvents such as methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone and cyclohexanone; toluene; Examples thereof include hydrocarbon solvents such as xylene and hexane, and halogenated hydrocarbon solvents such as dichloromethane, chloroform and trichloroethylene. It is preferable that these solvents are capable of dissolving the binder resin and have a water-soluble ratio of about 0 to 30% by weight. In addition, when industrialization, in consideration of work safety, cost and productivity, if the binder resin is polyolefin, use cyclohexane,
In the case of other binder resins, it is particularly preferable to use ethyl acetate.

[Dispersion Suspension Step] The dispersion suspension step is a step of preparing a suspension by dispersing and suspending the toner composition mixture prepared in the mixing step in an aqueous medium containing a dispersant. It is.

(Preparation of Aqueous Medium) As the aqueous medium, it is preferable to use an aqueous medium in which an inorganic dispersant is dispersed. In order to make the particle size distribution of the toner particles uniform, it is preferable to disperse the inorganic dispersant in water and to add a polymer dispersant soluble in water. This inorganic dispersant can be used in dispersing machines containing media such as ball mills, sand mills, attritors, and dyno mills;
It is dispersed in water using a high-pressure disperser such as PV Gaulin or a microfluidizer or an ultrasonic disperser. The polymer dispersant may be added by any method as long as it is uniformly dissolved in water. The water used in the present invention is usually ion-exchanged water, distilled water or pure water.

As the inorganic dispersant, it is preferable to use a hydrophilic dispersant, and specific examples include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, clay, diatomaceous earth, bentonite and the like. However, calcium carbonate is particularly preferred.
Further, it is more preferable that these inorganic dispersants have their particle surfaces coated with a polymer having a carboxyl group. When using one coated with such a polymer,
It is possible to produce stable toner particles. Further, as the polymer having a carboxyl group, a polymer having a number average molecular weight in the range of 1,000 to 200,000 is preferably used. Is too strong and may be buried in the particles, while if the molecular weight is too low, the contribution to dispersibility may be reduced. Specific examples include acrylic acid-based resin, methacrylic acid-based resin, fumaric acid-based resin, maleic acid-based resin, and the like, and the monomers constituting these are acrylic acid, methacrylic acid, fumaric acid, Homopolymers such as maleic acid or copolymers thereof and copolymers thereof with other vinyl monomers can also be used, and the carboxyl group can be a metal salt such as sodium, potassium, magnesium, ammonium or the like. It is preferably a salt structure such as a salt.

As a method of coating the particle surface of the inorganic dispersant with the polymer having a carboxyl group, the polymer is dissolved in water, the inorganic dispersant is added, and the mixture is mixed.
A method of drying, pulverizing or crushing, or a method of mixing in a dry state at the time of crushing the inorganic dispersant can be used. The coating amount of the polymer having a carboxyl group is about 0.01 to 5.0% by weight, and preferably 0.03 to 3.0% by weight, based on the total weight of the dispersant. As the inorganic dispersant, those having an average particle diameter in the range of 1 to 1000 nm are used, and preferably those in the range of 5 to 500 nm. The amount of the inorganic dispersant used is
The amount is from 1 to 500 parts by weight, preferably from 10 to 200 parts by weight, per 100 parts by weight of the toner.

As the polymer dispersing agent, a hydrophilic dispersing agent is preferably used, and among those having a carboxyl group, those having no lipophilic group such as a hydroxypropoxyl group and a methoxyl group are preferable. Specifically, water-soluble cellulose ethers such as carboxymethyl cellulose and carboxyethyl cellulose are used, and carboxymethyl cellulose is particularly preferred. These celluloses have a degree of etherification of 0.6 to 1.5 and an average degree of polymerization of 50 to 3000. Further, the carboxyl group may be a metal salt such as sodium, potassium and magnesium. These polymer dispersants have an optimal amount depending on the viscosity of the toner composition mixture, and if the amount is larger or smaller than the optimum amount, the particle size distribution of the formed particles will not be sharp. For this reason, the polymer dispersant has a viscosity of the aqueous medium of about 1 to 3000 mPa.
S, preferably 1 to 1000 m
It is preferable to add so as to obtain Pa · s. The polymer dispersant may be added by any method as long as it is uniformly dissolved in water.

(Preparation of Suspension) The suspension can be prepared by dispersing and suspending the toner composition mixture prepared in the mixing step in the aqueous medium. As a device for dispersing and suspending, a commercially available emulsifying machine or dispersing machine is used. For example, Ultra Turrax (manufactured by IKA), Polytron (manufactured by Kinematica), T
Batch-type emulsifier such as K-auto homomixer (manufactured by Tokushu Kika Kogyo), National Cooking Mixer (manufactured by Matsushita Electric Industrial), Ebara Milder (manufactured by Ebara Corporation), TK
Pipeline homomixer, TK homomix line flow, TK Filmix (manufactured by Tokushu Kika Kogyo Co., Ltd.), colloid mill (manufactured by Shinko Pantech Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Kakoki), Cavitron (Euro Tech), a continuous emulsifier such as a fine flow mill (manufactured by Taiheiyo Kiko), a batch or continuous dual-use emulsifier such as CLEARMIX (manufactured by M-Technic), a microfluidizer (manufactured by Mizuho Industries), a nanomizer ( High pressure emulsifiers such as Nanomizer Co., Ltd., APV gourin (manufactured by Goulin Co., Ltd.), membrane emulsifiers such as membrane emulsifier (manufactured by Reika Kogyo), vibrating emulsifiers such as vibro mixer (manufactured by Reika Kogyo) An ultrasonic emulsifier such as an ultrasonic homogenizer (manufactured by Branson) and the like can be mentioned.

[Polymerization Step] The polymerization step is a step of polymerizing the polymerizable monomer in the suspension prepared in the dispersion suspension step to produce a toner dispersion. In this polymerization step,
The polymerizable monomer in the suspension is polymerized by heating the suspension prepared in the dispersion suspension step to a temperature in the range of 20 ° C. or more and 100 ° C. or less while stirring and holding the suspension for 1 hour to 24 hours. Let it.

[Solvent Removal Step] The solvent removal step is a step of removing the solvent in the suspension night prepared in the dispersion suspension step to produce a toner dispersion. In this solvent removal step, (1) the suspension prepared in the dispersion suspension step is heated to a range of 20 ° C. or more and 100 ° C. or less, and (2) the suspension prepared in the dispersion suspension step is 1 kPa or more. The pressure is reduced to less than 3 kPa, (3) water is added to the suspension prepared in the dispersion suspension step, and (4) the suspension prepared in the dispersion suspension step is dissolved in both water and the solvent. (5)
Inert gas is blown into the suspension prepared in the dispersion suspension step, or (6) a gas stream is blown against the suspension prepared in the dispersion suspension step to forcibly update the gas phase on the suspension surface. By doing so, the solvent in the particles in the suspension is removed. These operations may be performed alone, but may be performed in any combination and simultaneously, or may be performed in any combination and in order.

As the water to be added in the above (3),
Generally, ion exchange water, distilled water or pure water is used. Further, as the other solvent that dissolves both the water and the solvent in the above (4), methanol, ethanol, 1-propanol, t-butyl alcohol, acetone and the like are used.

[Washing / Dewatering Step] The washing / dewatering step is a step of removing an aqueous medium from the toner dispersion liquid produced in the polymerization step or the solvent removing step, followed by washing and dewatering to prepare a toner cake or toner slurry. is there. In this washing and dehydrating step, the toner dispersion liquid produced in the solvent removing step is treated with an acid to dissolve the inorganic dispersant, and then washed with water and dehydrated. However, an alkali treatment may be added after the acid treatment.

[Drying Step] The drying step is a step of drying the toner cake or the toner slurry prepared in the solvent removing step to obtain toner particles. In the drying step in the present invention, it is necessary to use a loop type flash dryer. FIG. 1 is a schematic configuration diagram of an example of a loop-type flash dryer used in the method for producing a toner for developing an electrostatic image of the present invention. As shown in FIG. 1, for example, a loop type flash dryer is a stream blower 2 for supplying an air flow 7 to a ring-shaped pipe 1 (loop portion), a raw material for supplying a toner cake or a toner slurry. An air flow outlet 4 through which the toner whose moisture has evaporated is conveyed is provided inside the supply port 3 and the annular pipe 1, and the air flow outlet 4 is connected to a toner collecting section 5 through which the toner is collected. The toner cake or the toner slurry supplied from the raw material supply port 3 circulates through the annular pipe 1 together with the airflow 7 supplied from the airflow blowing port 2. The toner whose moisture has evaporated within approximately 10% is conveyed to the toner collecting section 5 together with the airflow from the airflow outlet 4 and collected.

The air flow inlet 2 needs to be supplied such that an air flow blows out from the annular pipe 1 substantially in a tangential direction and the air flow circulates in the annular pipe 1 in a certain direction. The linear velocity of the airflow at the airflow inlet 2 needs to be 30 m / s or more, and more preferably 50 m / s or more. As the linear velocity of the air flow increases, the moist toner in the annular pipe 1 is conveyed to the air flow and circulates, and the moisture evaporates instantaneously, and at the same time, the toner is loosened to the primary particles. Here, if the linear velocity of the airflow is less than 30 m / s, the toner is difficult to be conveyed even when the airflow circulates, and at the same time, the toner is not loosened while being aggregated. When the toner contains water and is heavy, the centrifugal force is high and the toner circulates outside the annular pipe 1. However, when the water evaporates and becomes light, the centrifugal force is low and the toner circulates inside the annular pipe 1. Then, dry toner is transported together with airflow from an airflow outlet 4 provided inside the annular pipe 1.

The temperature of the airflow at the airflow inlet 2 is:
The temperature must be 70 ° C. or higher, and more preferably 80 ° C. or higher. When the temperature of the airflow is less than 70 ° C,
The water in the toner cake or the toner slurry supplied from the raw material supply port cannot be sufficiently evaporated. The higher the temperature of the airflow, the more instantaneously the moisture of the toner evaporates. Usually, the upper limit of the temperature of the airflow is preferably about 140 ° C.
20 ° C. or lower is more preferable. The drying time of the toner cake or the toner slurry in the drying step is usually within 10 minutes. Further, the processing amount in the drying step is not particularly limited, and can be appropriately selected depending on the size of the apparatus.

The toner recovery section 5 is preferably a cyclone because it is the simplest. Here, the temperature of the airflow in the toner collecting section 5 needs to be 60 ° C. or lower, and more preferably 55 ° C. or lower. If the temperature of the airflow is higher than 60 ° C., it is not preferable because the toner is fused to the toner collecting portion and the toners are blocked. Further, the temperature of the air flow in the toner collecting section 5 is preferably 5 ° C. or less from the glass transition point (Tg) of the toner in that fusion of the toner and blocking of the toner can be prevented.

In the present invention, a second air flow supply port 8 is provided in the middle of the pipe between the air flow outlet 4 and the toner collecting section 5 to supply a second air flow having a temperature of 50 ° C. or less. A high-temperature air flow is supplied to the loop portion, so that the moisture of the toner can be instantaneously evaporated, and the temperature of the air flow can be reduced in the toner recovery portion, so that fusion of the toner and blocking between the toners can be prevented, which is preferable. . At this time,
It is preferable that the temperature of the air flow between the second air flow supply port 8 and the toner recovery unit 5 be 60 ° C. or less, since fusion of the toner and blocking of the toner can be prevented. The water content of the supplied toner is determined depending on the apparatus and operating conditions in the washing and dewatering process, which is the preceding process. The water content is approximately 20 to 50% when the toner cake is used, and approximately 50% when the toner slurry is used. A range of ~ 90% is preferred.

[Other Steps] In the method for producing a toner for developing an electrostatic charge image of the present invention, the following steps can be further added as necessary. First, there is a step of externally adding and sieving the toner particles obtained in the drying step. In these steps, the toner particles obtained in the drying step are externally added and sieved to obtain a toner for developing an electrostatic image. In these steps, any method may be used as long as the method does not cause aggregation or pulverization of the toner. Further, according to the production method of the present invention, toner particles having a sufficiently sharp particle size distribution can be obtained. However, when further higher toner characteristics are required, a classification step may be performed after the drying step.

Next, the toner for developing an electrostatic image of the present invention will be described. [Electrostatic Image Developing Toner] The electrostatic image developing toner of the present invention is manufactured by the above-described method of manufacturing an electrostatic image developing toner of the present invention, and has a sufficiently sharp particle size distribution. When such an electrostatic image developing toner is used, excellent transferability can be obtained in an electrostatic image developing method, and a good image can be stably provided.

The volume average particle diameter of the electrostatic image developing toner is preferably 1 to 15 μm, more preferably 3 to 10 μm. When the volume average particle diameter is less than 1 μm, the transfer rate tends to decrease, while the volume average particle diameter is 15 μm.
If m exceeds m, the image quality may deteriorate. In general, the toner used as an electrostatic image developing toner has 1% by weight or less of coarse particles having a volume average particle diameter of three times or more. If it exceeds 1% by weight, the transferability deteriorates, and the image quality such as fog and white spots tends to deteriorate.

Further, a toner generally used as a toner for developing an electrostatic image is a GSD (Geometrical) on the fine powder side.
Standard Deviation) is about 1.7, and the GSD on the coarse powder side is about 1.3. However, in order to achieve high performance such as high image quality and high reliability, the GSD value must be It needs to be even smaller. The GSD (fine powder) of the electrostatic image developing toner of the present invention is preferably 1.6 or less, and more preferably 1.45.
The following is more preferred. Further, the GSD (coarse powder) of the electrostatic image developing toner of the present invention is preferably 1.27 or less,
1.25 or less is more preferable. Here, the GSD (fine powder) of the toner for developing an electrostatic image is determined by using a number-based median diameter (hereinafter abbreviated as “D50p”) and an 84% diameter on a number-based sieve (hereinafter abbreviated as “D84p”). , GSD (fine powder)
= D50p / D84p. The GSD (coarse powder) of the toner for developing an electrostatic image uses a volume-based median diameter (hereinafter abbreviated as D “D50v”) and a volume-based 16% diameter on a sieve (hereinafter abbreviated as “D16v”). GSD
(Coarse powder) = defined as D16v / D50v. This value means that the closer to 1, the more monodisperse the particle size is.

[0037]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following description, “parts” means “parts by weight”. (Example 1) [Mixing step] ・ Styrene (polymerizable monomer) 60 parts ・ n-butyl methacrylate (polymerizable monomer)・ ・ ・ ・ ・ ・ 27 parts ・ C. I. Pigment Blue 15: 3 (colorant) 6 parts Paraffin wax (release agent: melting point 89 ° C) 5 parts Tetraphenylboron calcium (charge control) 0.5 part 2,2'-azobisisobutyronitrile (polymerization initiator) 1.5 parts The above components were prepared using Dynomill (manufactured by Shinmaru Enterprises). The mixture was dispersed to prepare 100 parts of a toner composition mixed solution containing a polymerizable monomer.

[Dispersion and Suspension Step] Calcium carbonate (primary average particle size: 80 nm) coated with 1% by weight of acrylic acid-maleic acid copolymer (number average molecular weight: 10000) 20 parts ・ Ion-exchanged water ・ ・ ・ ・ ・ ・ 130 parts The above components were prepared using a Dynomill (manufactured by Shinmaru Enterprises), and the average dispersion time was 20 parts. To obtain a surface-treated calcium carbonate dispersion. 1 part of carboxymethyl cellulose (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was mixed and dissolved in 150 parts of the obtained surface-treated calcium carbonate dispersion to obtain an aqueous medium. While stirring 151 parts of the aqueous medium at a peripheral speed of 20 m / s using a TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), 100 parts of the toner composition mixture was charged and stirred for 3 minutes. Stopped to give a suspension.

[Polymerization Step, Washing Dehydration Step] The above suspension was heated to 70 ° C. under a nitrogen atmosphere and stirred for 24 hours to heat polymerize the above polymerizable monomer to obtain a toner dispersion. The aqueous medium was removed from the obtained toner dispersion, washed and dehydrated to obtain a toner cake.

[Drying Step] To dry the above-mentioned toner cake, a flash jet drier (a Seishin company)
A 2 inch pipe diameter apparatus (loop type flash dryer) was used. The toner cake has a water content of 35%, and has a raw material supply port 3 of 4 kg / hr at a temperature of 20 ° C.
Supplied from The air stream 7 was supplied from the air stream inlet 2 to the annular pipe 1 (loop section) at a rate of 3 m ³ / min (converted to a standard state) at 100 ° C. At this time, the linear velocity of the airflow 7 at the airflow inlet 2 was calculated to be 200 m / s or more, and the temperature of the airflow at the toner recovery unit 5 was 50 ° C.
Thus, an electrostatic image developing toner was manufactured.

<Evaluation> The volume average particle size and particle size distribution of the obtained toner (Tg 60 ° C.) were measured using Coulter Multisizer II (manufactured by Coulter Inc.) (the same applies hereinafter). As a result, D50v of the toner was 6.5 μm and GS
D (fine powder) was 1.4 and GSD (coarse powder) was 1.25. Further, coarse particles having a volume average particle size of three times or more are 0.5
% By weight. Using this toner, an image was formed with A-color-935 manufactured by Fuji Xerox Co., Ltd., and the obtained image was visually evaluated. As a result, the image was excellent in fine line reproducibility.

Example 2 [Mixing Step] Polyester resin composed of bisphenol A propylene oxide adduct, bisphenol A oxide adduct, and terephthalic acid derivative (binder resin: Tg 66 ° C., Tm 106 ° C.)・ ・ ・ ・ ・ ・ ・ ・ 45 parts ・ C. I. Pigment Blue 15: 3 (colorant) ······ 3 parts · Paraffin wax (release agent: melting point 89 ° C) ····· 2.5 parts · Ethyl acetate (solvent) ··· ... 50 parts By dispersing the above components with a Dyno mill, 100 parts of a toner composition mixed solution in which a polyester resin was dissolved was prepared.

[Dispersion and Suspension Step] Calcium carbonate coated with 1% by weight of an acrylic acid-maleic acid copolymer (number average molecular weight: 10,000) having a carboxyl group as an ammonium salt structure (primary average particle size: 80 nm)・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 20 parts ・ Ion-exchanged water ・ ・ ・ ・ ・ ・ ・ 130 Part The above components were dispersed using a Dyno mill (manufactured by Shinmaru Enterprises Co., Ltd.) so that the average dispersion time was 30 minutes to obtain a surface-treated calcium carbonate dispersion.
To 150 parts of the obtained surface-treated calcium carbonate dispersion, carboxymethyl cellulose (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
One part was mixed and dissolved to obtain an aqueous medium. The aqueous medium 15
While stirring 1 part at a peripheral speed of 20 m / s by a TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), 100 parts of the above toner composition mixed liquid was charged, stirred for 3 minutes, and then stopped. A suspension was obtained.

[Solvent Removal Step] The suspension obtained in the dispersion suspension step was heated to 50 ° C. while stirring. 3 hours 5
The suspension was kept at 0 ° C. and then cooled to room temperature, and the solvent was removed from the suspension to obtain a toner dispersion. [Washing and dehydrating step] To 200 parts of the toner dispersion obtained in the solvent removing step, 55 parts of 10 mol / l hydrochloric acid was added.
Further, washing with ion-exchanged water by filtration was repeated four times to obtain a toner cake.

[Drying Step] In order to dry the above-mentioned toner cake, an apparatus having a 2-inch pipe diameter of a flash jet dryer (Seishin Enterprise) was used. The toner cake has a moisture content of 35% and a temperature of 20 ° C. and a weight of 4 kg.
/ Hr from the raw material supply port 3. Airflow 7 is 8
At 0 ° C., a rate of 2 m ³ / min (converted to a standard state) was supplied from the airflow inlet 2 to the annular pipe 1 (loop portion). At this time, the linear velocity of the airflow 7 at the airflow inlet 2 was calculated to be 120 m / s or more. In addition, a second airflow at 20 ° C. was supplied from the middle of the pipe between the airflow outlet 4 and the toner recovery unit 5. At this time, the temperature of the air flow in the toner collecting section 5 was 30 ° C. Thus, an electrostatic image developing toner was manufactured.

<Evaluation> D50v of the obtained toner was 5.
9 μm, GSD (fine powder) was 1.37, and GSD (coarse powder) was 1.24. In addition, coarse particles having a volume average particle diameter of 3 times or more were 0.4% by weight. Using this toner, an image was formed with A-color-935 manufactured by Fuji Xerox Co., Ltd., and the obtained image was visually evaluated.
The image was good.

(Example 3) A toner for developing an electrostatic image was manufactured in the same manner as in Example 1 except that the [drying step] was changed as follows, and the same evaluation as in Example 1 was performed. Was done. [Drying Step] A toner slurry was obtained without removing the aqueous medium from the toner dispersion obtained in [Polymerization Step] of Example 1. To dry the toner slurry, use a pipe diameter of 2
An inch type device was used. The toner slurry had a water content of 75%, and was supplied from the raw material supply port 3 at a temperature of 15 ° C. at a rate of 5 kg / hr. Air flow 7 is 3m at 140 ° C
^The air was supplied from the airflow inlet 2 to the annular pipe 1 (loop portion) at a rate of ³ / min (converted to a standard state). At this time,
The linear velocity of the airflow 7 at the airflow inlet 2 is calculated to be 200 m
/ S or more. In addition, a second airflow of 15 ° C. was supplied from the middle of the pipe between the airflow outlet 4 and the toner recovery unit 5. At this time, the temperature of the airflow in the toner collecting section 5 was 40 ° C.

<Evaluation> D50v of the obtained toner is 6.
5 μm, GSD (fine powder) was 1.4, and GSD (coarse powder) was 1.25. In addition, coarse particles having a volume average particle diameter three times or more were 0.5% by weight. Using this toner, an image was formed with A-color-935 manufactured by Fuji Xerox Co., Ltd., and the obtained image was visually evaluated.
The image was good.

Comparative Example 1 A toner for developing an electrostatic image was manufactured in the same manner as in Example 1 except that the [drying step] was changed as follows, and the same evaluation as in Example 1 was performed. Was done. [Drying Step] The above-mentioned toner cake was placed in a 50 ° C. tray-type oven drier and left to dry for 17 hours. <Evaluation> D50v of the obtained toner is 6.9 μm, GS
D (fine powder) was 1.4 and GSD (coarse powder) was 1.35. In addition, coarse particles having a volume average particle size of 3 times or more were 5% by weight. Compared with the results of Examples 1 to 3, the GSD (coarse powder) was broad and the number of coarse particles was large. Using this toner, an image was formed with A-color-935 manufactured by Fuji Xerox Co., Ltd., and the obtained image was visually evaluated.

Comparative Example 2 A toner for developing an electrostatic charge image was produced in the same manner as in Example 2 except that the [drying step] was changed as follows, and the same evaluation as in Example 2 was performed. Was done. [Drying Step] The above-described toner cake was placed in a 50 ° C. tray-type vacuum dryer and left to dry for 17 hours. <Evaluation> D50v of the obtained toner is 5.9 μm, GS
D (fine powder) was 1.4 and GSD (coarse powder) was 1.34. In addition, coarse particles having a volume average particle diameter of 3 times or more were 4% by weight. Compared with the results of Examples 1 to 3, the GSD (coarse powder) was broad and the number of coarse particles was large. Using this toner, an image was formed with A-color-935 manufactured by Fuji Xerox Co., Ltd., and the obtained image was visually evaluated.

Comparative Example 3 A toner for developing an electrostatic image was manufactured in the same manner as in Example 1 except that the [drying step] was changed as follows, and the same evaluation as in Example 1 was performed. Was done. [Drying Step] In order to dry the above-mentioned toner cake, an apparatus having a 2-inch pipe diameter of a flash jet dryer (Seishin Enterprise) was used. The toner cake had a water content of 35%, and was supplied from the raw material supply port 3 at a temperature of 25 ° C. at a rate of 4 kg / hr. Airflow 7 3m ³ at 140 ℃ /
min (converted to the standard state) at the rate of
To the annular pipe 1 (loop section). At this time, the linear velocity of the airflow 7 at the airflow inlet 2 is calculated to be 200 m / s.
As described above, the temperature of the airflow in the toner collecting section 5 was 80 ° C. <Evaluation> The obtained toner was aggregated and could not be evaluated. This is because the temperature of the air flow in the toner collecting section is 80
° C.

Comparative Example 4 A toner for developing an electrostatic image was produced in the same manner as in Example 2 except that the [drying step] was changed as follows, and the same evaluation as in Example 2 was carried out. Was done. [Drying process] In order to dry the above-mentioned toner cake, a pipe diameter of a flash jet dryer (Seishin Enterprise) 2
An inch type device was used. The toner cake had a water content of 35%, and was supplied from the raw material supply port 3 at a temperature of 20 ° C. at a rate of 2 kg / hr. Airflow 7 3m ³ at 60 ℃ /
min (converted to the standard state) at the rate of
To the annular pipe 1 (loop section). At this time, the linear velocity of the airflow 7 at the airflow inlet 2 is calculated to be 200 m / s.
That was all. In addition, a second airflow at 20 ° C. was supplied from the middle of the pipe between the airflow outlet 4 and the toner recovery unit 5.
At this time, the temperature of the airflow in the toner collecting section 5 was 25 ° C. <Evaluation> The obtained toner was not dried and could not be evaluated. This is because the temperature of the air flow supplied to the loop is 60
° C.

(Comparative Example 5) An electrostatic image developing toner was manufactured in the same manner as in Example 1 except that the [drying step] was changed as follows, and the same evaluation as in Example 1 was performed. Was done. [Drying Step] In order to dry the above-mentioned toner cake, an apparatus having a 2-inch pipe diameter of a flash jet dryer (Seishin Enterprise) was used. The toner cake had a water content of 35%, and was supplied from the raw material supply port 3 at a temperature of 20 ° C. at a rate of 2 kg / hr. Air flow 7 is 0.3 m ³ at 80 ° C
/ Min (converted to a standard state) at a rate of from the airflow inlet 2 to the annular pipe 1 (loop portion). At this time, the linear velocity of the air flow 7 at the air flow inlet 2 is calculated to be 20 m / s.
And the temperature of the airflow in the toner recovery section 5 was 25 ° C. <Evaluation> The obtained toner was not dried and could not be evaluated. This is because the linear velocity of the air flow supplied to the loop is 2
This is because it is as low as 0 m / s.

[0054]

According to the present invention, crushing and classification are unnecessary,
Particle size distribution is sufficiently sharp, and there are no coarse particles,
Further, the present invention can provide a toner for developing an electrostatic image, which is excellent in transferability and can stably obtain a good image, and a method for producing the same.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a loop-type flash dryer used in a method for producing a toner for developing an electrostatic image of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Annular piping (loop part) 2 Air flow blow-in port 3 Raw material supply port 4 Air flow extraction port 5 Toner recovery part 6 Toner 7 Air flow 8 Second air flow supply port

Claims (2)

[Claims] 1. A method for producing a toner for developing an electrostatic charge image having a drying step, wherein a loop type flash dryer is used in the drying step, and a temperature of 70 ° C. is applied to a loop portion of the flash dryer.
C. and at a linear velocity of 30 m / s or more, and the temperature of the airflow in the toner recovery section of the flash dryer is controlled to 60 ° C. or less. Method. 2. An electrostatic image developing toner obtained by the method for producing an electrostatic image developing toner according to claim 1.