JPH11295929A - Electrostatic latent image developing toner and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the yield of a toner having a desired grain size by subjecting toner mother particles pulverized to a desired grain size or below to a surface reforming treatment and classifying the particles to a prescribed grain size distribution. SOLUTION: A binder resin, coloring agents, and other desired additives are mixed, kneaded, pulverized and classified to obtain the particles having the desired grain size. These particles are then subjected to an instantaneous heat treatment. The grain size is 4 to 10 μm, more preferably 5 to 9 μm. The shape of the toner particles obtd. by the kneading-pulverizing method is controlled to a spherical and uniform shape and further the pores possessed on the surface are decreased and the smoothness may be enhanced by subjecting the particles to the instantaneous heat treatment. The control of the instantaneous heat treatment is facilitated by using a pulverizing apparatus capable of forming the particles to be pulverized to the spherical shape in the pulverizing stage. The control of circularity, etc., is facilitate by using a classifying apparatus capable of forming the particles to be treated to the spherical shape in the classifying stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for an electrostatic latent image used for electrophotography, electrostatic printing and the like, and a toner obtained by a method for producing the same.

[0002]

2. Description of the Related Art In recent years, there has been a demand for miniaturization, high speed, and low cost of copiers and printers, and various techniques have been developed to solve them. As one of the techniques, spherical toner is being studied, and polymerized toner and the like have been commercialized. However, in order to obtain a spherical toner, the cost performance is low with the current technology, and an enormous capital investment is required. Therefore, it is desired to reduce the price of the co-toner, improve the production efficiency and improve the quality in the future.

As a general method for producing a toner, first, a binder resin, a charge control agent, and a chromatic colorant are mixed using a Henschel mixer or the like, kneaded with a twin-screw extruder or the like, and cooled. After the obtained mixture is pulverized coarsely with a feather mill, further pulverized with a jet mill, and then subjected to an air classifier to obtain a toner having a desired particle size. As classifiers, mechanical classifiers and wind classifiers are generally known, and both utilize the balance between the centrifugal force and centripetal force applied to the toner when it is conveyed and the wind force for conveying the toner, and the Coanda effect. Classify. However, since the finely pulverized toner particles are indefinite, even if they have substantially the same size, the wind resistance is different. Moreover, the smaller the particle glass, the lower the flowable glass, the higher the cohesion, and the more difficult it is to disperse it into individual particles. Therefore, in the dispersion of irregular-shaped particles, both the toner group having a large particle size and the toner group having a small particle size after classification have a broad particle size distribution.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the present invention has been made to improve the classification accuracy of pulverized toner to improve the yield of toner having a desired particle size. The aim is to improve. Still another object of the present invention is to manufacture a toner suitable for miniaturization and high-speed operation with an electrophotographic process or a direct marking type image forming apparatus while improving the toner yield.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a toner composition containing at least a binder resin and a colorant is finely pulverized to a predetermined particle size or less to obtain toner base particles. The present invention relates to a method for producing a toner for developing an electrostatic latent image, which is characterized in that particles are subjected to a surface modification treatment with hot air and then classified into a predetermined particle size distribution, and a toner obtained by the method.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The binder resin used in the present invention is not particularly limited, and any resin used in a toner can be used in an appropriate combination. Specifically, polyester resin, vinyl resin (styrene resin, acrylic resin, olefin resin, etc.),
Any of synthetic resins and natural resins such as a diene resin, a polyester resin, an epoxy resin, a polyamide resin, a silicone resin, a phenol resin, a petroleum resin, and a urethane resin can be used. In particular, in order to obtain a substantially spherical toner having a uniform particle size distribution by the method of the present invention, the glass transition temperature is 50 ° C. or higher, more preferably 50 to 75 ° C., and the softening point is 80 to 160 ° C., more preferably 80 to 160 ° C. 120 ° C (for full color toner) or 80 to 150 ° C (for oil fixing toner or magnetic toner), number average molecular weight of 1,000 to 30,000, more preferably 2,500 to 50,000
30,000 (for full color) or 1000-
10,000 (in the case of oilless fixing toner or magnetic toner), weight-average molecular weight / number-average molecular weight of 2 to 10
0, more preferably 2 to 20 (in the case of full color toner) or 30 to 100 (in the case of oil fixing toner or magnetic toner) are suitable. Particularly preferred thermoplastic resins are polyester resins. A polyester resin having an acid value of 2 to 50 KOH mg / g, more preferably 3 to 30 KOH mg / g, is suitable. Two or more binder resins may be used in combination.

By using a polyester resin having such an acid value, the dispersibility of various pigments including carbon black and a charge control agent can be improved, and a toner having a sufficient charge amount can be obtained. Acid value is 2
If it is less than KOHmg / g, the above-mentioned effects are reduced, and if the acid value is more than 50 KOHmg / g, the stability of the toner charge amount against environmental fluctuations, especially humidity fluctuations, is impaired. As the polyester resin, those obtained by polycondensing a polyhydric alcohol component and a polycarboxylic acid component are preferable.

As the dihydric alcohol component of the polyhydric alcohol component, for example, polyoxypropylene (2,2)
2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2
Bisphenol A alkylene oxide adducts such as -bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl Glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A And the like.

Examples of the trihydric or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3
5-trihydroxymethylbenzene and the like.

The divalent carboxylic acid component of the polycarboxylic acid component includes, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid Succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, isooctenylsuccinic acid, n- Examples include octylsuccinic acid, isooctylsuccinic acid, anhydrides and lower alkyl esters of these acids.

Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid,
5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-
Dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,2
7,8-octanetetracarboxylic acid, pyromellitic acid,
Embolic dimer acids, anhydrides of these acids, lower alkyl esters and the like.

Further, as the polyester resin of the present invention, a polyhydric carboxylic acid having a polymerizable double bond is used as a part of the polyester raw material, and a monomer having a polymerizable double bond is further added to carry out copolycondensation. Unsaturated polyester resin may be used. Examples of the polycarboxylic acid having a double bond include itaconic acid, fumaric acid, maleic acid,
And phthalic acid and esters thereof. Examples of the raw material monomer for the polyester resin include the above-mentioned polyhydric alcohol component and polyvalent carboxylic acid component.

Examples of the monomer having a polymerizable double bond include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, and 2,4-dimethylstyrene. ,
Styrene or styrene derivatives such as p-tert-butylstyrene and p-chlorostyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; methyl methacrylate and n-methacrylic acid
Propyl, isopropyl methacrylate, n-methacrylate
-Butyl, isobutyl methacrylate, t-methacrylate
Butyl, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, methacrylic acid 3
-(Methyl) butyl, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate and the like; alkyl methacrylates; methyl acrylate, n-propyl acrylate, isopropyl acrylate , N-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid Nonyl, decyl acrylate,
Alkyl acrylates such as undecyl acrylate and dodecyl acrylate; acrylic acid, methacrylic acid,
Examples include vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether. As a polymerization initiator when polymerizing a monomer having a polymerizable double bond and a polyvalent carboxylic acid having a double bond which is a polyester forming component,
For example, 2,2′-azobis (2,4-dimethylvaleronitrile, 2,2′-azobisisobutyronitrile,
1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-
Examples include azo or diazo polymerization initiators such as dimethylvaleronitrile, and peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, and lauroyl peroxide.

In the present invention, in particular, to improve the fixability and the anti-offset property as an oilless fixing toner, or to control the glossiness of an image in a full-color toner requiring light transmission. It is preferable to use two types of polyester resins having different softening points as the polyester resins. In the oil-less fixing toner, a first polyester resin having a softening point of 95 to 120 ° C. is used in order to improve the fixing property.
Softening point of 130 to 1 to improve offset resistance
A second polyester resin at 60 ° C. is used. In this case, if the softening point of the first polyester resin is lower than 95 ° C., the offset resistance is lowered or the dot reproducibility is lowered. If the softening point is higher than 120 ° C., the effect of improving the fixability becomes insufficient. If the softening point of the second polyester resin is lower than 130 ° C., the effect of improving the offset resistance becomes insufficient, and
When the temperature is higher than 60 ° C., the fixing property is reduced. From such a viewpoint, the softening point of the first polyester resin is more preferably 100 to 115 ° C, and the softening point of the second polyester resin is 135 to 155 ° C. It is desirable that the first and second polyester resins have a glass transition point of 50 to 75 ° C, preferably 55 to 70 ° C. This is because if the glass transition point is low, the heat resistance of the toner becomes insufficient, and if the glass transition point is too high, the pulverizability at the time of production is lowered and the production efficiency is lowered.

The first polyester resin is a polyester resin obtained by polycondensation of the above-mentioned polyhydric alcohol component and polyhydric carboxylic acid component, particularly, a bisphenol A alkylene oxide adduct as a polyhydric alcohol component. A polyester resin obtained by using at least one selected from the group consisting of only terephthalic acid, fumaric acid, dodecenyl succinic acid, and ventictricarboxylic acid as a polycarboxylic acid component as a main component is preferable.

Further, as the second polyester resin,
Using a mixture of a raw material monomer of a polyester resin, a raw material monomer of a vinyl-based resin, and a bi-reactive monomer that reacts with the raw material monomers of both resins, a condensation polymerization reaction to obtain a polyester resin in the same container and a vinyl-based resin are performed. A polyester resin obtained by performing the obtained radical polymerization reaction in parallel is preferred from the viewpoint of improving the dispersibility of the wax, the toughness, the fixability, and the offset resistance of the toner. The content of the vinyl resin in the second polyester resin is 5 to 5.
It is 40% by weight, preferably 10 to 35% by weight. When the content of the vinyl resin is less than 5% by weight, the fixing strength of the toner is reduced. When the content is more than 40% by weight, the offset resistance, the toughness of the toner, and the negative charge level are liable to occur. Become. In addition, when the wax is contained in the toner, the dispersibility of the polyethylene wax tends to decrease when the content of the vinyl resin is less than 5% by weight, and the dispersibility of the polypropylene wax tends to decrease when the content exceeds 40% by weight. is there.

The weight ratio of the first polyester resin to the second polyester resin is from 7: 3 to 2: 8, preferably 6: 3.
It is preferable to set it to 4: 3: 7. By using the first polyester-based resin and the second polyester-based resin in such a range, the spread as a toner due to crushing at the time of fixing is small, the dot reproducibility is excellent, and the low-temperature and high-speed fixing properties are excellent. In the image forming apparatus described above, excellent fixability can be ensured. Also, excellent dot reproducibility can be maintained even when forming a double-sided image (when passing through the fixing device twice). If the proportion of the first polyester resin is smaller than the above range, the low-temperature fixability becomes insufficient and a wide fixability cannot be secured. If the proportion of the second polyester resin is smaller than the above range, the offset resistance tends to decrease and the toner is crushed at the time of fixing, and the dot reproducibility tends to decrease.

Full color requiring translucency-Conventionally, Sharp Melt type resin having a molecular weight distribution of Sharp name has been used, and a glossy pictorial image has been reproduced by using such a resin. However,
In recent years, there has been a case in which an image with reduced glossiness is required in a normal office color or the like. Such a requirement can be achieved, for example, by expanding the molecular weight distribution of the resin on the polymer side. Also,
As one of the rough concrete measures, two kinds of different resin properties having different molecular weights have a glass transition temperature of 50 to 75 ° C, a softening point of 80 to 120 ° C, and a number average molecular weight of 2500 to 30,000.
If the weight-average molecular weight / number-average molecular weight is 2 to 20, it can be suitably used. When the glossiness is lowered, the value of weight average molecular weight / number average molecular weight is set to 4 or more, and the melt viscosity curve is inclined, so that the glossiness control region with respect to the fixing temperature can be expanded. .

In addition, epoxy resins can be preferably used especially in full-color toners. As the epoxy resin used in the present invention, a polycondensate of bisphenol A and epichlorohydrin can be suitably used.
For example, epomic R362, R364, R365, R
367, R369 (all manufactured by Mitsui Petrochemical Industries, Ltd.), Epotote YD-011, YD-012, YD-014,
YD-904, YD-017 (all manufactured by Toto Kasei)
Commercially available products such as Epicoat 1002, 1004, 1007 (all manufactured by Ciel Chemical Co., Ltd.) can also be used.

In the present invention, the softening point of the resin is determined by using a flow tester (CFT-500: manufactured by Shimadzu Corporation), and using a die having a diameter of 1 mm and a length of 1 mm.
kg / cm 2, 1 cm under the condition of a heating rate of 6 ° C./min
The temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when the sample No. 2 was melted out was set as the softening point. The glass transition point was determined using a differential scanning calorimeter (DSC-200: manufactured by Seiko Instruments Inc.) as an alumina reference,
A sample of 10 mg was heated at a rate of 10 ° C./min for 20 minutes.
The temperature was measured between ℃ 120 ° C., and the shoulder value of the main endothermic peak was defined as the glass transition point. The acid value was determined by dissolving a 10 mg sample in 50 ml of toluene and titrating with a pre-specified N / 10 potassium hydroxide / alcohol solution using a mixed indicator of 0.1% bromthymol blue and phenol red. / 10 This is a value calculated from the consumption amount of potassium hydroxide / alcohol solution. Further, the molecular weight (the number average molecular weight and the weight average molecular weight indicate values calculated in terms of styrene using gel permeation chromatography (GPC)).

Further, the toner of the present invention may contain a wax in order to improve properties such as offset resistance. Examples of such waxes include polyethylene wax, polypropylene wax, carnauba wax, rice wax, sasol wax, montan ester wax, Fischer-Tropsch wax and the like. In the case where the wax is contained in the toner as described above, the content is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the binder resin in order to obtain the effect of the addition without causing a problem such as filming. Is preferred.

It is preferable to add a polypropylene wax from the viewpoint of improving the offset resistance, and it is preferable to use a smear property (a roller is used to feed a paper on which an image has already been formed on one side at the time of automatic document feeding or duplex copying). It is preferable to contain polyethylene wax from the viewpoint of improving the image quality (phenomenon of image quality deterioration such as blurring or smearing caused by rubbing of the image). Particularly preferred from the above viewpoints are polypropylene waxes having a melt viscosity at 160 ° C. of 50 to 300 cps, a softening point of 130 to 160 ° C. and an acid value of 1 to 20 KOHmg / g. Melt viscosity at 1000C is 1000-8000
It is a polyethylene wax having a cps and a softening point of 130 to 150 ° C. That is, the polypropylene wax having the above-mentioned melt viscosity, softening point and acid value is excellent in dispersibility in the above-mentioned binder resin, and can improve the offset resistance without causing a problem due to the free wax. In particular, when a polyester resin is used as the binder resin, it is preferable to use an oxidized wax.

Examples of the oxidized wax include polyolefin-based oxidized wax, carnauba wax, monta wax, rice wax and Fischer-Tropsch wax. As a polypropylene wax, which is a polyolefin wax, low molecular weight polypropylene has the disadvantage of lowering the fluidity of toner due to its low hardness, and in order to improve this disadvantage, it is modified with carboxylic acid or acid anhydride. Are preferred. In particular, the low molecular weight polypropylene resin is selected from the group consisting of (meth) acrylic acid, maleic acid and maleic anhydride.
A modified polypropylene resin modified with at least one kind of acid monomer can be suitably used. The modified polypropylene is obtained by, for example, grafting or adding an at least one acid monomer selected from the group consisting of (meth) acrylic acid, maleic acid and maleic anhydride to a polypropylene resin in the presence or absence of a peroxide catalyst. It is obtained by doing.
When using a modified polypropylene, the acid value is 0.5
-30 KOHmg / g, preferably 1-20 KOHmg / g
g.

Commercially available oxidized polypropylene waxes include Viscol 200TS (softening point 140 ° C., acid value 3.5) and Viscol 100TS (softening point 140 ° C., acid value 3) manufactured by Sanyo Chemical Industries, Ltd. .5),
Viscol 110TS (softening point 140 ° C, acid value 3.5)
Etc. can be used. A commercially available oxidized polyethylene is Sunwax E30 manufactured by Sanyo Chemical Industries.
0 (softening point 103.5 ° C, acid value 22), sunwax E
250P (softening point 103.5 ° C., acid value 19.5), high wax 4053E manufactured by Mitsui Petrochemical Industries, Ltd. (softening point 1
45 ° C, acid value 25), 405MP (softening point 128 ° C, acid value 1.0), 310MP (softening point 122 ° C, acid value 1.
0), 320MP (softening point 114 ° C, acid value 1.0), 2
10MP (softening point 118 ° C, acid value 1.0), 220MP
(Softening point 113 ° C, acid value 1.0), 220MP (softening point 113 ° C, acid value 1.0), 4051E (softening point 120)
° C, acid value 12), 4052E (softening point 115 ° C, acid value 2
0), 4202E (softening point 107 ° C., acid value 17), 22
03A (softening point 111 ° C., acid value 30) and the like can be used.

When carnauba wax is used, it is preferably microcrystalline and has an acid value of 0.5 to 10 KOH mg / g, preferably 1 to 6 KOH mg / g. The montan wax generally refers to a montan-based ester wax refined from minerals, is a microcrystal like carnauba wax, and has an acid value of 1 to 20, preferably 3 to 15. Rice wax is a product of air oxidation of rice bran wax,
The acid value is preferably 5 to 30 KOHmg / g.

Fischer-Tropsch wax is a wax produced as a by-product when a synthetic petroleum is produced from coal by a hydrocarbon synthesis method, and is commercially available, for example, under the trade name "Sazol wax" manufactured by Sazor Corporation. In addition, Fischer-Tropsch wax, which uses natural gas as a starting material, can be suitably used because it has a low molecular weight component and has excellent heat resistance when used in a toner. The acid value of Fischer-Tropsch wax is 0.5 to 3
0 KOH mg / g can be used, and among the sasol waxes, especially those of the oxidation type having an acid value of 3 to 30 KOH mg / g (trade names, Sasol wax A1, A2
Etc.) can be preferably used. Further, the polyethylene wax having the above-mentioned melt viscosity and softening point also has excellent dispersibility in the above-mentioned binder resin, and achieves an improvement in smear property by reducing the coefficient of friction of the fixed image surface without causing problems due to free wax. Can be. The melt viscosity of the wax was measured using a Brookfield viscometer.

As the colorant for full color, known pigments and dyes are used. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red,
Quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 122, C.I.
I. Pigment Red 57: 1, C.I. I. Pigment Red 184, C.I. I. Pigment Yellow 97,
C. I. Pigment Yellow 12, C.I. I. Pigment Yellow 17, C.I. I. Solvent Yellow 16
2, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3 and the like. In the black toner, in addition to various carbon blacks, activated carbon, and titanium black, a part or all of the colorant can be replaced with a magnetic substance.
Known magnetic particles such as ferrite, magnetite, and iron can be used as such a magnetic material. The average particle size of the magnetic particles is preferably 1 μm or less, particularly preferably 0.5 μm or less, from the viewpoint of obtaining dispersibility at the time of production. In the case where it is added from the viewpoint of preventing scattering while giving the properties as a non-magnetic toner, the amount of addition is 0.5 to 10 parts by weight, preferably 0.5 to 8 parts by weight, per 100 parts by weight of the binder resin. Parts by weight, more preferably 1
-5 parts by weight. If the addition amount exceeds 10 parts by weight, the magnetic binding force of the developer carrying member (with a built-in magnet roller) to the toner becomes strong, and the developability is reduced.

When used as a magnetic toner,
The magnetic material is preferably 20 to 60 parts by weight based on 100 parts by weight of the binder resin. If the amount is less than 20 parts by weight, toner scattering tends to increase. If the amount is more than 60 parts by weight, the toner charge cannot be stably secured, resulting in deterioration of image quality.

The toner of the present invention can be used by adding additives such as a charge controlling agent and a release agent to the binder resin according to the purpose. For example, examples of the charge control agent include a fluorine-containing surfactant, a metal-containing dye such as a salicylic acid metal complex and an azo-based metal compound, a polymer acid such as a copolymer containing maleic acid as a monomer component, and a quaternary. Ammonium salts, azine dyes such as nigrosine, carbon black and the like can be added. A magnetic powder or the like may be added to the toner of the present invention as needed.

Further, it is preferable to add various organic / inorganic fine particles to the toner of the present invention as a fluidity modifier before surface modification and / or after adjusting toner particles.
Examples of inorganic fine particles include various carbides such as silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, and diamond carbon lactam. , Boron nitride, titanium nitride, various nitrides such as zirconium nitride, borides such as zirconium boride, oxides, titanium oxide,
Various oxides such as calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, silica, and colloidal silica; various titanate compounds such as calcium titanate, magnesium titanate, and strontium titanate;
Sulfides such as molybdenum disulfide, fluorides such as magnesium fluoride and carbon fluoride, various metal soaps such as aluminum stearate, calcium stearate, zinc stearate and magnesium stearate, and various non-magnetic inorganic fine particles such as talc and bentonite Can be used alone or in combination. Particularly, in the case of inorganic fine particles such as silica, titanium oxide, alumina and zinc oxide, conventionally used hydrophobizing agents such as silane coupling agents, titanate coupling agents, silicone oils and silicone varnishes, and fluorine-containing agents The surface treatment is preferably performed by a known method using a silane coupling agent, a fluorine-based silicone oil, a coupling agent having an amino group or a quaternary aluminum base, or a modified silicone oil. The relatively large-diameter inorganic fine particles such as metal titanate and various organic fine particles may or may not be subjected to a hydrophobic treatment. The addition amount of these fluidizers is
The amount added before the heat treatment is 0.1 to 6 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the developer particles. In addition, in the external addition treatment after the heat treatment, 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight is added to 100 parts by weight of the developer particles. It is preferable to adjust the amount to be used.

The toner of the present invention is obtained by mixing, kneading, pulverizing and classifying the binder resin, the colorant and other desired additives by a conventional method to obtain particles having a desired particle size. Heat-treats the particles obtained as described above. The particle size is 4 to 10 μm, preferably 5 to 9 μm. The particles obtained at this stage have almost the same particle size distribution even after being subjected to the instantaneous heat treatment.

The classification step may be performed after performing the instantaneous heating treatment in the present invention. At this time, it is preferable to use a pulverizing apparatus capable of spheroidizing the particles to be pulverized as a pulverizing apparatus used in the pulverizing step, since it is easy to control the instantaneous heat treatment performed thereafter. Examples of such an apparatus include an innomizer system (manufactured by Hosokawa Micron Corporation) and a crypton system (manufactured by Kawasaki Heavy Industries, Ltd.). Further, by using a classifier capable of spheroidizing particles to be treated as a classifier used in the classifying step, control of circularity and the like becomes easy. Examples of such a classifier include a teaplex type classifier (manufactured by Hosokawa Micron).

Further, in combination with the instantaneous heat treatment shown in the present invention, it may be combined with various kinds of processing in a surface modifying apparatus for various kinds of developers. These surface reforming devices include surface modification using a high-speed air impact method such as a hybridization system (Nara Machinery Co., Ltd.), a Kryptron Cosmos system (Kawasaki Heavy Industries, Ltd.), and an innomizer system (Hosokawa Micron). Surface modification equipment that applies dry mechanochemical methods such as quality equipment, mechano fusion system (manufactured by Hosokawa Micron), mechano mill (manufactured by Okada Seiko), disper coat (manufactured by Nisshin Engineering), coatmizer (manufactured by Freund Sangyo) The surface modification apparatus to which the wet coating method of (2) is applied can be used in appropriate combination.

According to the present invention, the shape of the toner particles obtained by the kneading-pulverization method is controlled to a spherical and uniform shape by performing an instantaneous heat treatment, and further, the pores on the toner surface are reduced. And smoothness can be increased.
Due to this, the charging uniformity and image performance are excellent,
In addition, a toner that achieves stable image performance for a long period of time without the occurrence of selective development such that toner having a specific particle size and shape component in a developer and a toner having a specific charge amount is consumed first does not occur. Can be provided.

The toner according to the present invention is mainly composed of a binder resin having a high softening point suitable for high-quality, low-consumption (high-filling-color-material) and energy-saving fixing systems, which is highly demanded in recent years. Small particle size toner with high loading of
Adhesion to the toner carrier (carrier, developing sleeve, developing roller, etc.), photoreceptor, and transfer member is optimized and excellent in mobility. Furthermore, it has excellent fluidity, has improved uniformity of charging, and has stable durability characteristics for a long period of time. In the case of a magnetic toner, by performing such an instantaneous heating treatment, the binder resin of the magnetic particles is melted and spheroidized, and the magnetic powder exposed on the surface is eliminated and free fine powder is removed from the surface of the magnetic particles. Fixed to

Specifically, the average circularity is 0.950 or more and the standard deviation of the average circularity is 0.040 or less. More preferably, in the case of a color toner (including a black toner), the average circularity is 0.960 or more, and the average circularity and the standard deviation are 0.035 or less. In the case of oilless fixing toner or magnetic toner, the average circularity is 0.95.
It is 0 or more, preferably 0.960 or more, and the standard deviation of the average circularity is 0.040 or less, preferably 0.036 or less. In the case of a magnetic toner, the average circularity is 0.950 or more, and the standard deviation of the average circularity is 0.040 or more.

In the present specification, the average circularity is the average of values calculated by the following equation: circularity = perimeter of a circle equal to the projected area of a particle / perimeter of a projected image of the particle. The "perimeter of a circle equal to the projected area of the particle" and the "perimeter of the particle projection image" are the flow type particle image analyzer (EPIA-1000 or EPIA-1000).
IA-2000; manufactured by Toa Medical Electronics Co., Ltd.) in an aqueous dispersion system. 1
Is closer to a true sphere. As described above, since the average circularity is obtained from “the perimeter of a circle equal to the projected area of a particle” and “the perimeter of a projected image of a particle”, the value accurately determines the shape of the toner particle, that is, the unevenness of the particle surface. It is an index to be reflected in. The average circularity is the value of the toner particles.
(3000), the reliability of the average circularity in the present invention is extremely high. In addition,
In the present specification, the average circularity does not have to be measured by the above-mentioned device, but may be measured by any device that can be determined in principle based on the above equation.

The standard deviation of the circularity refers to the standard deviation in the circularity distribution, and the value can be obtained simultaneously with the average circularity by the flow type particle image analyzer. The smaller the value is, the more uniform the toner particle shape is.

In order to treat the post-treatment agent powder with the hydrophobizing agent, for example, the hydrophobizing agent alone or the mixture is diluted with a solvent such as tetrahydrofuran (THF), toluene, ethyl acetate, methyl ethyl ketone or acetone, and the post-treatment is performed. The diluent of the coupling agent is added dropwise or by a method such as spraying while the agent powder is forcibly stirred with a blender or the like, mixed well, and the resulting mixture is heated and dried. If necessary, the dried product is again stirred with a blender and sufficiently pulverized. When a plurality of types of hydrophobizing agents are used, they may be used simultaneously or separately subjected to the above treatment. Instead of the dry method, a so-called wet method in which a hydrophobizing agent is dissolved in an organic solvent, a post-treatment agent is immersed in the solvent, and dried and crushed may be used. The post-treatment agent is preferably subjected to a heat treatment at about 100 ° C. or more before the hydrophobic treatment.

The amount of the hydrophobizing agent varies depending on the type of the post-treatment agent, but is usually 0.1 to 5% by weight, preferably 0.2 to 3% by weight of the post-treatment agent. When the amount is less than 0.1% by weight, the effect of hydrophobization is not obtained, and when the amount is more than 5% by weight, agglomerates of the post-processing agents are generated so much that the original effects of the post-processing agents such as improvement in the fluidity of the developer cannot be achieved.

Conventionally, surface modification by heat is known, but in many cases, the developer is supplied while a hot air flow is circulating. In this case, the developers are liable to agglomerate with each other, and the shape after the processing has a large variation. Also,
By dispersing and supplying developer particles in a hot air stream,
A method is known in which the surface of the developer particles is melted and the developer particles are instantaneously spheroidized. It is also known that the surface of the developer particles is previously treated with hydrophobic silica or the like in order to improve the dispersion state of the developer particles in hot air. However, even with these methods, sphericity and its uniformity could not be achieved in order to dramatically improve the developer characteristics.

The surface treatment modification by hot air used in the present invention is not achieved by the conventional method, because the developer is surface-modified by heat by dispersing and spraying toner particles with compressed air in hot air. It achieves sphericity and its uniformity.

A schematic configuration diagram of an apparatus for performing surface treatment modification by hot air will be described with reference to FIGS. As shown in FIG. 1, high-temperature and high-pressure air (hot air) prepared by a hot-air generating device 101 passes through an inlet pipe 102 and a hot-air injection nozzle 10.
Injected from 6. On the other hand, the toner particles 105 are supplied from the fixed amount supply device 104 by a predetermined amount of pressurized air into the introduction pipe 10.
It is conveyed through 2 ′ and is sent to a sample injection chamber 107 provided around the hot air injection nozzle 106.

As shown in FIG. 2, the sample injection chamber 107 has a hollow donut shape, and a plurality of sample injection nozzles 103 are arranged at equal intervals on the inner wall. The toner particles sent to the sample ejection chamber 107 are diffused and uniformly dispersed in the ejection chamber 107, and the plurality of sample ejection nozzles 1
03 is injected into the hot air stream.

Further, the sample injection nozzle 103 is so set that the jet flow of the sample injection nozzle 103 does not cross the hot air flow.
Is preferably provided with a required inclination. Specifically, it is preferable that the toner jet flow is jetted so as to follow the hot air flow to some extent, and the angle between the toner jet flow and the flow direction of the central region of the hot air flow is 20 to 40 °, preferably 25 °.
~ 35 ° is preferred. If it is wider than 40 °, the toner jet flow will be jetted across the hot air flow, and will collide with the toner particles jetted from other nozzles, causing aggregation of the toner particles. If the width is too narrow, toner particles that cannot be taken into the hot air are generated, and the shape of the toner particles becomes non-uniform.

Further, a plurality of sample injection nozzles 103 are required, and at least three or more and four or more are preferable. By using a plurality of sample injection nozzles, it is possible to uniformly disperse the toner particles in the hot air stream, and it is possible to reliably perform the heat treatment for each toner particle. As for the state ejected from the sample ejecting nozzle, it is desirable that it is widely diffused at the time of ejection and is dispersed throughout the hot air flow without colliding with other toner particles.

The toner particles thus ejected are instantaneously brought into contact with high-temperature hot air to be uniformly heated. Here, the term “instantaneous” refers to a time during which the necessary modification (heating treatment) of the toner particles is achieved and the aggregation of the toner particles does not occur, which varies depending on the processing temperature and the concentration of the toner particles in the hot air stream. , Usually 2 seconds or less, preferably 1 second or less. This instantaneous time is expressed as the residence time of the toner particles until the toner particles are ejected from the sample ejection nozzle and introduced into the introduction pipe 102 ". When the residence time exceeds 2 seconds, coalesced particles are generated. Next, the toner particles heated instantaneously are immediately cooled by the cooling air introduction unit 1.
08 is cooled by the cold air introduced from the inlet pipe 10 without adhering to the device wall or agglomerating the particles.
After passing through 2 ", it is collected by the cyclone 109 and stored in the product tank 111. After the toner particles have been collected, the transport air further passes through the bag filter 112 to remove fine powder, and then passes through the blower 113 into the atmosphere. Preferably, a cooling jacket through which cooling water of cyclone 109 flows is provided to prevent aggregation of toner particles.

Other important conditions for performing surface treatment modification with hot air include a hot air flow, a dispersed air flow, a dispersed concentration,
Processing temperature, cooling air temperature, suction air volume, cooling water temperature.

The hot air flow is the amount of hot air supplied by the hot air generator 101. It is preferable to increase the amount of hot air in order to improve the uniformity of heat treatment and the processing capacity.

The amount of dispersed air is the amount of air sent into the introduction pipe 102 'by pressurized air. Although depending on other conditions, it is preferable that the amount of the dispersed air be reduced and heat-treated because the dispersed state of the toner particles is improved and stabilized.

The dispersion concentration refers to the dispersion concentration of the toner particles in the heat treatment region (specifically, the nozzle discharge region). The preferred dispersion concentration depends on the specific gravity of the toner particles, and the value obtained by dividing the dispersion concentration by the specific gravity of each toner particle is 50 to 300 g.
/ M3, preferably 50 to 200 g / m3.

The processing temperature means the temperature in the heat treatment area temperature area. In the hot air processing area, there is a temperature gradient from the center to the outside, but it is preferable to reduce the temperature distribution for the processing. It is preferable to supply the wind in a laminar state from a surface of the apparatus by a stabilizer or the like. In the case of a non-magnetic toner using a binder resin having a sharp molecular weight distribution, for example, a binder resin having a weight average molecular weight / number average molecular weight of 2 to 20, a peak temperature higher by 100 ° C. to 300 ° C. than the glass transition point of the binder resin. It is preferable to process in the range. More preferably, the treatment is performed in a peak temperature range of 120 ° C. to 250 ° C. higher than the glass transition point of the binder resin. Note that the peak temperature range refers to the maximum temperature in a region where the toner contacts hot air.

Binder resins of a type having a relatively wide molecular weight distribution, for example, a weight average molecular weight / number average molecular weight of 30 to 30
In the case of a non-magnetic toner using a binder resin having 100, the glass transition point of the binder resin is 1 point.
The treatment is preferably performed at a peak temperature range higher by 00 ° C to 300 ° C. More preferably, the treatment is performed in a peak temperature range of 150 ° C. to 280 ° C. higher than the glass transition point of the binder resin. This is because, in order to improve the uniformity of the shape and surface of the toner, it is necessary to set a higher processing temperature so that the modification of the high molecular weight region of the binder resin can be achieved. However, if the processing temperature is set higher, coalesced particles are more likely to be generated. Therefore, it is necessary to tune the fluidization processing before the heat treatment by setting a relatively large amount or setting a low dispersion concentration during the processing. .

When wax is added to toner particles, coalesced particles are likely to be generated. Therefore, the fluidization treatment before the heat treatment (particularly, a fluidizing agent having a large particle size component) is set to be relatively large. Tuning, such as setting the dispersion concentration at the time of processing to be low, is important in obtaining uniform toner particles with reduced shape and shape variation. This operation becomes more important when a binder resin having a relatively wide molecular weight distribution is used or when the processing temperature is set to be higher in order to increase the sphericity.

The cooling air temperature is the temperature of the cooling air introduced from the cooling air introduction unit 108. After the surface treatment of the toner particles is modified by hot air, it is preferable to return the toner particles to an atmosphere below the glass transition point by cooling air in order to instantly cool the toner particles to a temperature region where aggregation or coalescence of the toner particles does not occur. For this reason, the cooling air is cooled at a temperature of 25 ° C. or lower, preferably 15 ° C. or lower, more preferably 10 ° C. or lower. However, if the temperature is lowered more than necessary, dew condensation may occur depending on conditions, and conversely, a side effect occurs, so care must be taken. In such surface treatment modification with hot air, the time during which the binder resin is in a molten state is extremely short, in addition to the cooling by the cooling water in the apparatus described below, so that particles adhere to each other and to the walls of the heat treatment apparatus. Disappears. As a result, the stability during continuous production is excellent, the frequency of cleaning the manufacturing apparatus can be extremely reduced, and the yield can be controlled stably with high yield.

The suction air volume means air for conveying the toner particles processed by the blower 113 to the cyclone. It is preferable to increase the amount of the suction air from the viewpoint of reducing the cohesiveness of the toner particles.

The cooling water temperature refers to cyclones 109 and 11
4 and the temperature of the cooling water in the cooling jacket provided by the introduction pipe 10. ) Cooling water temperature is 25 ° C or less,
It is preferably at most 15 ° C, more preferably at most 10 ° C.

In order to increase the sphericity (circularity) and to reduce the variation in the shape, it is preferable to make further efforts as described below.

The amount of toner particles supplied into the hot air stream is controlled to be constant so that pulsation or the like is not generated. For this purpose: (i) A combination of a plurality of types of table feeders, vibrating feeders, and the like used in 115 in FIG. If the table feeder and the vibratory feeder can be used to perform high-precision quantitative supply, it is possible to connect the pulverization or classification step and supply the toner particles to the heat treatment step online as it is;

(Ii) After supplying the toner particles with compressed air,
Before the toner particles are supplied into the hot air, the toner particles are supplied to the sample supply chamber 107.
Re-dispersed within to increase uniformity. For example, means of redispersion by secondary air, provision of a buffer section to make the dispersion state of toner particles uniform, or redispersion by a coaxial double tube nozzle or the like is adopted;

Optimizing and uniformly controlling the dispersion concentration of toner particles when sprayed and supplied in a hot air stream. To do this:

(I) The hot air stream is supplied uniformly from all directions and in a highly dispersed state. More specifically, when supplying from a dispersion nozzle, a nozzle having a stabilizer or the like is used to improve the dispersion uniformity of toner particles dispersed from each nozzle;

(Ii) In order to make the dispersion concentration of the toner particles in the hot air flow uniform, the number of nozzles should be at least 3 or more, preferably 4 or more, as described above, and should be as large as possible. They are arranged symmetrically with respect to the direction. 3
The toner particles may be supplied uniformly from a slit provided in the entire circumference of 60 degrees;

The temperature distribution of the hot air in the region where the toner particles are processed is controlled so that uniform heat energy is applied to all the particles, and the hot air is controlled in a laminar flow state. . To do this:

(I) To reduce the temperature variation of the heat source for supplying the hot air; (ii) To make the straight pipe portion before the hot air supply as long as possible. Alternatively, it is preferable to provide a stabilizer near the hot air supply port for stabilizing the hot air. Further, FIG.
Is an open system, which tends to diffuse hot air in a direction in which it comes into contact with outside air, so that the hot air supply port may be narrowed as necessary;

The toner particles have been subjected to a fluidization treatment so as to maintain a uniform dispersion state during the heat treatment. (I) In order to ensure the dispersion and fluidity of the toner particles, it is preferable to use various organic / inorganic fine particles of 1/20 or less, preferably 1/50 or less of the particle size of the toner particles. In particular, inorganic fine particles (particularly hydrophobic silica fine particles) having an average diameter of primary particles of 20 nm or less (BET specific surface area of 100 m 2 / g or more) and subjected to a hydrophobic treatment are preferable. Addition amount:
0.1 to 6 parts by weight, based on 100 parts by weight of the toner particles,
Preferably, 0.5 to 3 parts by weight are added;

(Ii) The mixing treatment for improving the dispersion / fluidity is preferably present in a uniform and strongly immobilized state on the surface of the toner particles;

Even when the surface of the toner particles receives heat, particles that do not soften because the spacer effect between the toner particles can be maintained on the surface of the toner particles.
To do this:

(I) It is preferable to add fine particles which have a larger particle size than the various organic / inorganic fine particles shown above and which do not soften at the processing temperature. Due to the presence of the present particles on the surface of the toner particles, even after starting to receive heat, the surface of the toner particles does not become a surface of only the complete resin component, and brings about a spacer effect between the toner particles,
Prevent aggregation and coalescence of toner particles;

(Ii) Among the fluidizing agents shown above, the large particles have an average primary particle size of more than 20 nm, preferably more than 25 nm, and a BET specific surface area of 90 m ² / g or less, preferably 70 m ² / g or less. Particles having a particle size of ² / g or less are used. The amount of the large-diameter particles added is 100 toner particles.
0.05 to 5 parts by weight, preferably 5 parts by weight,
0.3 to 3 parts by weight are added.

The collection of the heat-treated product must be controlled so as not to generate heat. For this purpose: (i) The particles which have been heat-treated and cooled are cooled by a chiller in order to suppress heat generated in a piping system (particularly a radius portion) and a cyclone usually used for collecting toner particles. Is preferred.

In the processing of a magnetic toner having a small resin component that can contribute to heat treatment and having a relatively large specific gravity, the space to be heat-treated is surrounded in a cylindrical shape to substantially increase the processing time, It is preferable to perform the process twice.

The surface-treated and modified toner fine particles are classified into a predetermined particle size distribution. As a classifier, a classifier conventionally used for classifying toners can be used. These classifiers are roughly classified into those using the balance between the centrifugal force and the centripetal force applied to the toner and those using the Coanda effect, but are not limited to these. The former is basically a wind classifier (for example, a DS classifier (manufactured by Nippon Pneumatic Industries, Ltd.)) and a mechanical classifier (for example, a rotor classifier (Deepplex type 100ATP)
(Made by Hosokawa Micron Corporation)). A composite type of these functions or another function may be used.

The principle of classification based on the Coanda effect is based on the fact that the direction of movement is different if the particle diameter is different, due to the inertial force acting on the particle and the resistance of the fluid generated by the movement of the particle. In other words, this is a classification method utilizing the property that "a jet flows along this wall surface if the wall surface is placed on only one side thereof". This principle is shown in FIG. 3 (conceptual diagram of the Coanda effect principle). In the classifier, a curved airflow (301) is created from top to bottom by suction of a blower, and raw material powder (304) is introduced into the curved airflow from a raw material supply nozzle (303) in contact with the upper surface of the Coanda block (302). When ejected with air, the powder flies along a curved airflow, depending on the respective particle size, so that the small particles (305) fly near the substantially semi-circular curved surface (Coanda circle) (306) of the Coanda block and the large particles (305). 307) fly further outside.
In this case, the larger the particle specific gravity of the raw material powder and the higher the ejection speed from the raw material supply nozzle, the larger the flight trajectory (flights further outward). By placing a partition (classification edge) (308) downstream of the airflow, products with different particle sizes can be obtained. The particle size can be adjusted by changing the position of the partition plate. Adjustment of classification accuracy and particle size can be performed by adjusting the position of the classification edge, feed air pressure, suction air volume,
Although it can be determined by the feed rate or the like, the position of the classification edge is particularly important in adjusting these. That is, on a straight line connecting the center O of the substantially semicircular curved surface (Coanda circle) of the Coanda block and the end of each edge, the distance from the end of the Coanda circle to the end of each edge is represented by FΔR.
, And MΔR, when both are changed in a direction to increase them, the respective classification points become large, and the particle size of the product becomes coarse.

Classifiers that use the Coanda effect are typically broadly classified into wind classifiers, elbow jet classifiers, and the like. The elbow jet classifier has multiple (for example, three or more) discharge holes from the elbow,
The classified toner is discharged with different particle diameters from the discharge holes, so that a toner having a plurality of particle diameter ranges can be obtained at one time. The use of particles is particularly preferred because a very sharp particle size distribution is obtained.

According to the method of the present invention, a substantially spherical fine particle toner having a uniform particle diameter can be obtained. In particular, a circularity of 0.96 to 1.0, preferably 0.965 to 0.995, a circularity standard deviation, which was very difficult to obtain by the conventional method or could not be put into practical use due to industrial profitability, 0.0
It is possible to easily obtain a toner of 40 or less, particularly 0.035 or less. If the circularity is smaller than 0.960, particles having a crack near the toner surface, which are observed by the pulverization method, are likely to be obtained, and image noise such as voids and unevenness in shape are likely to occur.

The obtained toner has a very sharp particle size distribution, and has a good toner performance, for example, a charge rising characteristic.
Because basic performance such as sharp charge amount distribution is improved,
A toner with little noise such as fogging, excellent image quality, no phenomenon such as selective development (a phenomenon of toner having a specific particle size and charge amount being consumed first), and excellent printing durability can be obtained. .

In the present specification, the circularity is a value represented by circularity = perimeter of a circle equal to the projected area of a particle / perimeter of a projected image of a particle. In the formula, “the perimeter of a circle equal to the projected area of the particle” and “the perimeter of the projected image of the particle” are flow type particle image analyzers (EPIA-1000 or EPIA-2
000: manufactured by Toa Medical Electronics Co., Ltd.) using a water-dispersed system to indicate a value (may be measured by another device if the measurement principle is the same). The closer to 1, the closer to a circle. As described above, the degree of circularity is obtained from “the perimeter of a circle equal to the projected area of a particle” and “the perimeter of a particle projected image”. Therefore, this value is an index that reflects the shape of the toner particles, that is, the unevenness of the particle surface. Becomes In the present specification, the circularity means an average value of 3000 toners unless otherwise specified.

The standard deviation of the circularity refers to the standard deviation of the circularity distribution, which can be obtained simultaneously with the average circularity using a flow type particle image analyzer. The smaller the value, the more uniform the particle diameter of the toner.

Further, as described above, toners having various circular particle diameters, for example, 6 μm and 8 μm, having the above-mentioned circularity and circularity standard deviation, can be produced simultaneously.

The color toner and the oilless fixing toner have the following formula: D / d50 (where D = 6 (ρ · S) (where D is a conversion from the specific surface area when the toner shape is a sphere) Value (μm), d50 is 50% equivalent particle size (μm) of relative weight distribution by particle size, ρ is density (g / cm ² ), S
Represents a BET specific surface area (m ² / g), and D / d50 is preferably 0.50 or more, and in the case of a magnetic toner, it is preferably 0.20 or more, and more preferably 0.25 or more. According to the above, such a range can be easily obtained. This D / d50 is an index indicating that there are pores on the surface or inside of the toner particles. In the case of a toner having the above value, the toner is cracked around the pores or an external additive or the like is contained in the concave portions. It is possible to suppress the generation of fine powder due to being buried or the protruding portion being shaved.

[0082]

The present invention will be described below in detail with reference to examples. Production Example of Resin Polyester resin A: A 2-liter four-necked flask was equipped with a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer, and was set in a mantle heater. The reaction was carried out by heating and stirring while introducing nitrogen into the flask. The progress of the reaction was monitored while measuring the acid value. When the acid value reached a predetermined value, the reaction was terminated. The number average molecular weight Mn was 4,800, and the weight average molecular weight Mw.
A polyester resin A having a ratio Mw / Mn of 3.9 to the number average molecular weight Mn, a glass transition temperature of 61 ° C., and a softening temperature of 102 ° C. was obtained.

Polyester resin B: (Production of polyester resin L) Polyoxypropylene (2,2)-was placed in a glass four-necked flask equipped with a thermometer, stirrer, falling condenser and nitrogen inlet tube.
2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid and fumaric acid in a weight ratio of 82:77:
The mixture was adjusted to 16:32:30 and added together with dibutyltin oxide as a polymerization initiator. This was reacted in a mantle heater under a nitrogen atmosphere at 220 ° C. with stirring. The softening point of the obtained polyester resin L is 110
℃, glass transition point is 60 ℃, acid value is 17.5 KOHmg
/ G.

(Production of polyester resin H) Styrene and 2-ethylhexyl acrylate were added in a weight ratio of 17:
The mixture was adjusted to 3.2, and put into a dropping funnel together with a polymerization initiator, digimyl peroxide. On the other hand, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) was placed in a glass four-necked flask equipped with a thermometer, a stirrer, a falling condenser, and a nitrogen inlet tube.
Propane, polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid, 1,2,4-benzenetricarboxylic acid and acrylic acid in a weight ratio of 42: 1.
The mixture was adjusted to 1: 11: 11: 8: 1 and added together with the polymerization initiator dibutyltin oxide. This was stirred at 135 ° C. under a nitrogen atmosphere in a mantle heater,
After styrene or the like was dropped from the dropping funnel, the temperature was raised to 23
The reaction was performed at 0 ° C. The obtained polyester resin H has a softening point of 150 ° C, a glass transition point of 62 ° C, and an acid value of 24.
It was 5 KOHmg / g.

The resin L and the resin H were dry-mixed with a Henschel mixer at a ratio of 5: 5 to obtain a polyester resin B.

Production of toner base particles 70 parts by weight of magenta masterbatch polyester resin A (Tg: 61 ° C., Tm: 102 ° C.) 30 parts by weight of magenta pigment (CI pigment red 184) 30 parts by weight of a mixture having the above composition The kneader was charged and kneaded. The obtained kneaded material was cooled and pulverized by a feather mill to obtain a pigment master batch.

Toner mother particles 1 Polyester resin A 93 parts by weight Pigment master batch 10 parts by weight Zinc salicylate metal complex (E84; manufactured by Orient Chemical Industry Co., Ltd.) 2 parts by weight Oxidized low-molecular-weight polypropylene (Viscol TS200; manufactured by Sanyo Chemical Industries, Ltd.) 1 part by weight) After sufficiently mixing the material having the above composition with a Henschel mixer, the mixture was melt-kneaded with a twin-screw extrusion kneader (PCM-30; manufactured by Ikegai Iron Works Co., Ltd.) having a larger diameter nozzle at the outlet. After the obtained kneaded material was quickly cooled, it was coarsely pulverized with a feather mill. The crushed material is jet-milled (I
DS; manufactured by Nippon Pneumatic Industries Ltd.) to obtain toner base particles 1 having a volume average particle size of 5.5 μm.

Toner mother particles 2 100 parts by weight of polyester resin B Carbon black (Mogal L; manufactured by Cabot) 8 parts by weight Zinc salicylate metal complex (E84; manufactured by Orient Chemical Industries) 3 parts by weight Oxidized low-molecular-weight polypropylene (Viscol TS200) 2 parts by weight of the material having the above composition, in the same manner as in the method for producing the toner base particles 1, and the toner base particles 2 having a volume average particle size of 5.6 μm.
I got

Measurement method of glass transition point Tg of resin Differential scanning calorimeter (DSC-200: manufactured by Seiko Electronics Co., Ltd.)
The alumina was used as a reference, and a 10 mg sample was measured at a heating rate of 10 ° C./min between 20 and 160 ° C., and the shoulder value of the main endothermic peak was used as the glass transition point.

Measurement method of softening point Tm of resin Using a flow tester (CFT-500: manufactured by Shimadzu Corporation), the pores of a die (diameter 1 mm, length 1 mm), pressure 2
1 kg under the condition of 0 kg / cm2 and a heating rate of 6 ° C / min.
The temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when the m2 sample was melted and flowed out was taken as the softening point.

Measurement method of molecular weight The number average molecular weight and the weight average molecular weight were measured using gel permeation chromatography (807-IT: manufactured by JASCO Corporation).
And tetrahydrofuran as a carrier solvent in 1
Flow at 0 kg / cm3, dissolve 30 mg of the sample to be measured in 20 ml of tetrahydrofuran, and add 0.5 mg of this solution.
Was introduced together with the above-mentioned carrier solvent, and determined in terms of polystyrene.

Measurement of Toner Particle Size The toner particle size was measured using a Coulter Multisizer 2.

Pretreatment (Pretreatment 1) 0.6 parts by weight of hydrophobic silica TS500 (manufactured by Cabosil) 0.3 part by weight of hydrophobic silica NAX50 (manufactured by Nippon Aerosil Co.) is added to 100 parts by weight of toner base particles. And a peripheral speed of 30 m / sec using a Henschel mixer.
The mixing process was performed for 90 seconds at c.

(Pretreatment 2) Hydrophobic silica R974 (manufactured by Nippon Aerosil Co., Ltd.) 0.6 part by weight with respect to 100 parts by weight of toner base particles Silica 90G (BET specific surface area: 90 m 2 / g; manufactured by Nippon Aerosil Co., Ltd.) 0.3 parts by weight of 10% surface treatment of disilazane was added, and the peripheral speed was 30 m / sec using a Henschel mixer.
The mixing process was performed for 90 seconds at c.

(Pretreatment 3) Silica 90G (BET specific surface area: 90 m 2 / g; 100 parts by weight of toner base particles)
Nippon Aerosil Co., Ltd.) with 10 hexamethyldisilazane
Then, 1.0 part by weight of the surface-treated surface was added, and the mixture was mixed at a peripheral speed of 30 m / sec for 90 seconds using a Henschel mixer.

(Pretreatment 4)-Production Example of Hydrophobic Titanium Oxide-In the step of obtaining hydrous titanium oxide by the sulfuric acid method, the hydrolysis rate was adjusted to obtain hydrous titanium oxide of a predetermined particle size, and after washing, 300 ℃, average primary particle diameter 25nm,
Titanium oxide A having a BET specific surface area of 110 m2 / g was obtained. While mixing and stirring each of the titanium oxides A in an aqueous system at a ratio of 2% by weight, n-butyltrimethoxysilane as a hydrophobizing agent was added and mixed at a ratio of 10% by weight with respect to the titanium oxide particles. Dry, crush and BE
Hydrophobic titanium oxide fine particles A having a T specific surface area of 98 m2 / g were obtained. Silica 90 per 100 parts by weight of toner base particles
G (BET specific surface area: 90 m 2 / g; manufactured by Nippon Aerosil Co., Ltd.) and 10 parts by weight of hexamethyldisilazane were added to 1.0 part by weight, and 0.5 part by weight of hydrophobic titanium oxide fine particles A were added thereto. Circumferential speed 30m / s
The mixing process was performed at ec for 90 seconds.

Heat treatment conditions The obtained toner was subjected to a surface treatment under the following conditions by a surface modifying apparatus (surfusing system; manufactured by Nippon Pneumatic Industries, Ltd.) shown in FIG. (Heat treatment condition 1) Maximum temperature; 155 ° C, residence time;
5 seconds, powder dispersion concentration; 100 g / m3, cooling air temperature; 1
8 ° C, cooling water temperature 20 ° C. (Heat treatment condition 2) Maximum temperature; 185 ° C, residence time;
5 seconds, powder dispersion concentration; 100 g / m3, cooling air temperature; 1
8 ° C, cooling water temperature 10 ° C. (Heat treatment condition 3) Maximum temperature; 260 ° C, residence time;
5 seconds, powder dispersion concentration; 100 g / m3, cooling air temperature; 1
8 ° C, cooling water temperature 10 ° C. (Heat treatment condition 4) Maximum temperature; 350 ° C, residence time;
5 seconds, powder dispersion concentration; 100 g / m3, cooling air temperature; 1
8 ° C, cooling water temperature 10 ° C. (Heat treatment condition 5) Maximum temperature; 450 ° C, residence time;
5 seconds, powder dispersion concentration; 100 g / m3, cooling air temperature; 1
8 ° C, cooling water temperature 10 ° C.

In the examples, the following classifiers were used. Classifier 1: Elbow jet classifier Classifier 2: Rotor classifier (Tiplex: type 100 ATP; manufactured by Hosokawa Micron).

(Toner A) A toner was obtained by using pre-treatment 1 and heat treatment conditions 3 using toner base particles 1. Furthermore, with an elbow jet classifier (classifier 1), 0.1 for 2D or more
% And 1/2 pop or less are classified as 12%, and 100 parts by weight of the toner is mixed with hydrophobic silica R974.
0.5 parts (manufactured by Nippon Aerosil Co., Ltd.) and 0.5 parts of strontium titanate particles (average particle size: 0.3 μm) were added, and the mixture was added at a peripheral speed of 30 m / sec using a Henschel mixer.
The mixing process was performed for 80 seconds. Thereafter, the mixture was sieved with a circular vibrating sieve (mesh size: 77 μm) to obtain toner A.

(Toners B to D, F to I, M) Toners B to D, F were prepared in the same manner as toner A except for the conditions (toner base particles, pretreatment, and heat treatment conditions) shown in the attached sheet list. ~
I and M were obtained. (Toner J) Toner J was obtained in the same manner as for toner A, except that the treatment was performed under the conditions without pretreatment (toner base particles, heat treatment conditions) shown in the conditions of the attached sheet list. (Toner K) Toner K was obtained in the same manner as for toner A, except that the toner was classified by the classifier 1 using the ordinary pulverizing method (without heat treatment) shown in the conditions in the attached sheet list. (Toner L) Toner L was obtained in the same manner as for toner A, except that the toner was classified by the classifier 2 using the ordinary pulverizing method (without heat treatment) shown under the conditions described in the attached table.

Evaluation yield—Classified coarse particles for toner: Determined from the weight of the toner before and after classification. Hollow-out: Continuous copying was performed in the same manner as in the evaluation method of the cleaning property, and the hollow images were evaluated by visually observing the copied images in the N / N environment at the initial stage and after continuous copying of 2000 sheets (after endurance). The criteria are as follows. The amount of toner adhering to the paper was adjusted to 1.0 mg /
cm ² (± 0.1). ：: No void was found on the copied image. Δ: Although some hollows occurred on the copied image, there was no practical problem. ×: Many hollow spots occurred on the copied image, and there was a practical problem. Table 1 shows the test results.

[0102]

[Table 1]

In Table 1, the toner particle size after classification is basically as follows.
D50 = 6.2 ± 0.1 μm, 2D or more = 0.1 ± 0.
1% (0.2% or less), 1 / 2pop or less = 12 ± 0.
1% is set as the target value.

[0104]

According to the present invention, it is possible to obtain fine toner particles having an arbitrary particle size substantially close to a true sphere with a sharp particle size distribution, and the obtained toner has a uniform particle surface. In addition, it is possible to obtain a toner which is excellent in fluidity and dispersibility and provides stable image quality. In addition, classification can be performed accurately with a simple method using a conventional general classification device, and the direct yield can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for surface modification treatment using hot air.

FIG. 2 is a schematic horizontal sectional view of a sample ejection chamber of the apparatus of FIG.

Fig. 3 Principle conceptual diagram of Coanda classifier

[Explanation of symbols]

 REFERENCE SIGNS LIST 101 hot air generator 102, 102 ′, 102 ″ inlet tube 103 sample injection nozzle 104 quantitative feeder 105 toner particles 106 hot air injection nozzle 107 sample injection chamber 108 cooling air introduction unit 109 cyclone 111 product tank 112 bag filter 113 blower 114 siphon 115 Feeder 301 Curved air flow 302 Coanda block 303 Raw material supply nozzle 304 Raw material powder 305 Small particle 307 Large particle 308 Partition plate (classifying edge)

Continued on the front page (72) Inventor Tsutsui Main Tax 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Minoru Nakamura 2--3 Azuchicho, Chuo-ku, Osaka-shi, Osaka No. 13 Osaka International Building Minolta Co., Ltd. (72) Inventor Hiroyuki Fukuda 2-3-1 Azuchicho, Chuo-ku, Osaka-shi, Osaka Osaka International Building Minolta Co., Ltd.

Claims (6)

[Claims] 1. A toner composition containing at least a colorant and a binder resin is finely pulverized to a predetermined particle size or less to obtain toner base particles, and the obtained toner base particles are subjected to a surface modification treatment with hot air. And then classifying the toner into a predetermined particle size distribution. 2. A toner obtained by the method according to claim 1, wherein the circularity is 0.96 to 1.0 and the circularity standard deviation is 0.040 or less. 3. The toner according to claim 2, which is used for a full-color process. 4. The toner according to claim 2, which is used in a non-magnetic one-component developing system. 5. The method according to claim 1, wherein at least one kind of inorganic fine particles is externally added before the heat treatment step. 6. The method according to claim 1, wherein the surface modification treatment with hot air is performed at a temperature 100 to 300 ° C. higher than the glass transition point of the binder resin for a toner.