JP2000003069A - Toner for developing electrostatic latent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner for developing an electrostatic latent image excellent in cleanability, stability of a charged state and transferability. SOLUTION: The toner has 4-12 μm volume average particle diameter, an average circularity of >=0.96 and a standard deviation of circularity of <=0.040 and contains 1-10% by number of coalesced particles. The toner is obtained by instantaneously heating toner matrix particles, which are obtd. by mixing, kneading and comminuting at least a colorant and a resin binder, with hot air, has an average circularity of 0.96-1.0, 4-12 μm volume average particle diameter and a standard deviation of circularity of <=0.04 and contains 1-10% by number of coalesced particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing toner used for electrophotography, electrostatic printing and the like.

[0002]

2. Description of the Related Art A developer for developing an electrostatic latent image used in a system such as electrophotography or electrostatic printing is conventionally produced by a wet method typified by a kneading-pulverization method or a suspension polymerization method. Further, it is known that after improving developer particles, the surface is modified by various methods (mechanical impact force, heat, etc.) in order to improve the characteristics of the particles obtained by these methods. Among them, it is also known that the surface is modified (spheroidized) by instantaneous heat treatment. For example, Japanese Patent Application Laid-Open No. Hei 4-226476 discloses a method in which a resin particle and a developer composition (carbon black, a quaternary ammonium salt having an average particle size of several μm, polypropylene, etc.) are mixed and then subjected to an instantaneous heating treatment. Disclose a toner (non-magnetic toner) which is melted and adhered. However, in this method, a relatively large amount of agglomerated particles or coalesced particles are generated, and the uniformity of the toner is impaired. ).

[0003] In particular, in recent years, with the demand for color images, there has been a tendency to use a resin having a low melt viscosity as a binder resin for the toner, and when the melt viscosity of the resin becomes low, for example, Japanese Patent Application Laid-Open No. 6-317933 is also disclosed. As described, aggregation of toner particles is likely to occur due to the heat of the surface modification treatment. In order to solve these problems, it is conceivable to lower the set temperature of the heat treatment apparatus. However, in that case, the degree of spheroidization was reduced, and it was difficult to obtain good transferability.

[0004] On the other hand, the more the particles become spherical, the more the transferability can be generally improved, but it becomes very difficult to clean the residual toner on the surface of the photoreceptor or on the intermediate transfer member, and the image quality and transferability become poor. The problem of deterioration (deterioration) occurs. As described above, it is difficult for the conventional technique to ensure (achieve) sufficient cleaning properties, charging stability and transfer properties.

[0005]

That is, the present invention provides:
The present invention relates to an electrostatic latent image developing toner having excellent cleaning properties, charging stability and transfer properties.

[0006]

According to the present invention, the volume average particle diameter is 4 to 12 μm, the average circularity is 0.96 or more, the circularity standard deviation is 0.040 or less, and the unified particles are 1 to 10 μm. The present invention relates to a toner for developing an electrostatic latent image, characterized in that the toner is contained in a number%.

The inventors of the present invention have made the toner particles spherical as described above to reduce the variation in the particle shape,
In addition, it has been found that by including a specific amount of the coalesced particles, the cleaning property, the transfer property and the charging stability at the time of copying using the toner are improved.

In the present invention, the toner is instantaneously heated with hot air to reduce the uniformity of the surface and the variation in the shape of each individual particle, thereby improving the charging start-up characteristics of the toner. In addition, since the charge amount distribution can be sharpened, noise such as fog is reduced, and the image quality can be improved. Further, when the present invention is applied to the one-component developing method, phenomena such as selective development (a phenomenon in which toner having a specific particle size and charge amount is consumed first) and the like do not occur. Stable toner quality can be ensured even during printing.

Further, the use of the toner according to the present invention increases efficiency such as mobility (developability and transferability).
The window of machine setting conditions expands.

The toner of the present invention has an average circularity of 0.960.
As described above, it preferably has a value of 0.965 to 0.995, a circularity standard deviation of 0.040 or less, and preferably 0.035 or less. If the average circularity is less than 0.960, cracks near the surface of the toner particles, which are observed when the toner base particles are manufactured by a pulverization method, and unevenness of the surface uniformity and shape, such as non-uniformity of charge and voids, etc. Image noise is likely to occur.
On the other hand, when the circularity standard deviation exceeds 0.040, the dispersion of the particles becomes large, and the transferability is deteriorated, and the rise in charge of the toner is reduced, which causes image noise. Further, a phenomenon such as selective development occurs, and stable toner quality cannot be ensured for printing durability.

In the present specification, the average circularity is represented by the following formula:

(Equation 1) The “perimeter of a circle equal to the projected area of a particle” and the “perimeter of a projected particle image” are flow particle image analyzers (FPIA-1000 or FIA).
PIA-2000; manufactured by Toa Medical Electronics Co., Ltd.) is shown in a value obtained by performing measurement in an aqueous dispersion system. The closer to 1, the closer to a perfect circle. 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. Further, since the average circularity is a value obtained as an average value of 3000 toner particles, the reliability of the average circularity in the present invention is extremely high. Note that, in the present specification, the average circularity does not have to be measured by the above device,
In principle, any device that can be determined based on the above equation may be used for measurement.

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. FIG. 4 is a photograph showing the particle structure of toner particles having a high average circularity.

Furthermore, the toner of the present invention contains one united particle.
% To 10%, preferably 1 to 7%, more preferably 2 to 5%. When the content of the coalesced particles is less than 1% by number, the effect of the coalesced particles is not effective, that is, cleaning failure occurs in which the untransferred toner remains on the surface of the photoreceptor and / or the surface of the intermediate transfer body.
It causes filming and the like. In particular, this phenomenon occurs remarkably when a cleaning means using a cleaning blade is employed, and is considered to be caused by slippage of untransferred toner. On the other hand, when the content exceeds 10% by number, image noise such as white spots, black spots, and density unevenness is generated, and a problem occurs in fine line reproducibility. In particular, when the toner is used in the one-component system, the problem in the regulating portion, that is, the thin layer unevenness and spillage become remarkable.

In the present specification, the term “coalesced particles” refers to particles in which a plurality of toner particles are fused and adhered to the surface by heat or the like, for example, the particles shown in FIG. Therefore, the meaning is different from the aggregated particles in which a plurality of toner particles are aggregated (collected), for example, the particles contacted at a point as shown in FIG. The coalesced particle content is expressed as a ratio of the number of particles recognized as coalesced particles to all toner particles by photographing the toner particles and recognizing the shape thereof. Is not required. As a device for photographing the shape of the toner particles, any device may be used as long as it can accurately form an image of the shape of the toner particles. In addition, an electronic photograph (copy) of a photograph showing the toner particle structure shown in FIGS. 4 to 6 is submitted as a reference photograph by a simultaneously submitted property submission form.

The toner of the present invention comprises at least a binder resin and a colorant.

As the binder resin used in the present invention, known thermoplastic synthetic resins and natural resins used as a binder resin for forming a toner can be used. For example, styrene resin, acrylic resin,
Synthetic resins such as olefin-based resins, diene-based resins, polyester-based resins, polyamide-based resins, epoxy-based resins, silicone-based resins, phenol-based resins, petroleum resins, and urethane-based resins, and natural resins. In the present invention, the glass transition temperature is 50 to 75 ° C., and the softening point is 80 to 1
It is preferable to use a resin having a number average molecular weight of 1000 to 30,000 and a weight average molecular weight / number average molecular weight of 2 to 100 at 60C.

In particular, when a full-color toner (including a black toner) is intended, the glass transition point is 50 to 75 ° C.
Softening point 80-120 ° C, number average molecular weight 2000-300
It is preferable to use a resin having a weight average molecular weight of 00 and a weight average molecular weight of 2 to 20. When an oilless fixing toner or a magnetic toner is intended, a first resin having a glass transition point of 50 to 75 ° C. and a softening point of 80 to 125 ° C. and a glass transition point of 50 to 75 ° C. and a softening point of 125 to 125 ° C.
It is preferable to use a binder resin comprising the second resin at 160 ° C.

More preferably, the toner binder resin component has the above characteristics and an acid value of 2 to 50 KOHm.
g / g, preferably 3 to 30 KOH mg / g of a polyester resin. By using a polyester resin having such an acid value, it is possible to improve the dispersibility of various pigments including carbon black and a charge control agent, and to obtain a toner having a sufficient charge amount. When the acid value is less than 2 KOHmg / g, the above-described effects are reduced, and when the acid value is more than 50 KOHmg / g, the stability of the toner charge amount against environmental changes, particularly humidity changes, is impaired.

As the polyester resin, a polyester resin obtained by polycondensing a polyhydric alcohol component and a polycarboxylic acid component can be used.

As the dihydric alcohol component of the polyhydric alcohol component, for example, polyoxypropylene (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.

Examples of the divalent carboxylic acid component of the polycarboxylic acid component include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and 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.

In the present invention, a mixture of a raw material monomer of the polyester resin, a raw material monomer of the vinyl resin, and a monomer which reacts with the raw material monomers of both resins is used as the polyester resin in the same container. A resin obtained by performing a polycondensation reaction for obtaining a polyester resin and a radical polymerization reaction for obtaining a styrene-based resin in parallel can also be suitably used. The monomers that react with the raw material monomers of both resins are, in other words, monomers that can be used for both the condensation polymerization reaction and the radical polymerization reaction. That is, a monomer having a vinyl group capable of undergoing a radical polymerization reaction with a carboxy group capable of undergoing a condensation polymerization reaction,
For example, fumaric acid, maleic acid, acrylic acid, methacrylic acid and the like can be mentioned.

The raw material monomers for the polyester resin include the above-mentioned polyhydric alcohol component and polyhydric carboxylic acid component.

The raw material monomers for the vinyl resin include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 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,
Unsaturated carboxylic acids such as itaconic acid and maleic acid; acrylonitrile, maleic ester, itaconic ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether And the like. As a polymerization initiator when polymerizing the raw material monomer of the vinyl resin, for example,
2,2′-azobis (2,4-dimethylvaleronitrile, 2,2′-azobisisobutyronitrile, 1,1 ′
-Azobis (cyclohexane-1-carbonitrile),
An azo or diazo polymerization initiator such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile;
Examples thereof include peroxide-based polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, and lauroyl peroxide.

As the binder resin component for the toner, a vinyl resin comprising the above-mentioned raw material monomers can be used. Among the vinyl resins, a styrene acrylic resin obtained by copolymerizing styrene or a styrene derivative with an alkyl methacrylate and / or an alkyl acrylate is preferable.

In the present invention, as the oilless fixing toner, it is preferable to use two kinds of resins having different softening points as the binder resin in order to improve the fixing property and the anti-offset property. Using a first resin having a softening point of 80 to 125 ° C. to improve fixability,
A softening point of 125 to 1 to improve offset resistance
A second resin at 60 ° C. is used. In this case, if the softening point of the first resin is lower than 80 ° C., the offset resistance is lowered or the dot reproducibility is lowered. If the softening point is higher than 125 ° C., the effect of improving the fixability is insufficient. The softening point of the second resin is 1
When the temperature is lower than 25 ° C., the effect of improving the offset resistance becomes insufficient, and when the temperature is higher than 160 ° C., the fixability decreases. From such a viewpoint, the softening point of the first resin is preferably 95 to 120 ° C, more preferably 100 to 115 ° C.
The softening point of the second resin is preferably 130 to 160 ° C,
More preferably, it is 135 to 155 ° C. It is desirable that the first and second 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. Further, it is preferable that the softening point of the second resin is higher than the softening point of the first resin by 10 ° C. or more, preferably by 15 ° C. or more.

The weight ratio of the first resin to the second resin is 7: 3 to
2: 8, preferably 6: 4 to 3: 7. By using the first resin and the second resin in such a range, the spread of the toner due to crushing at the time of fixing is small, the dot reproducibility is excellent, and the low-temperature and high-speed image forming apparatus is excellent in the low-temperature fixing property. In this case, excellent fixability can be secured. 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 resin is less than the above range, the low-temperature fixability becomes insufficient and a wide fixability cannot be secured. When the proportion of the second 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.

In the present invention, a full-color resin which is required to have a light-transmitting property has conventionally used a sharp-melt type resin having a sharp molecular weight distribution. By using such a resin, a glossy Victorian image can be reproduced. You. However, in recent years, there has been a case in which an image with reduced glossiness is required for a normal office color or the like. Such a requirement can be achieved, for example, by expanding the molecular weight distribution of the resin toward the polymer. In addition, as one of the specific measures, it can be achieved by using two or more kinds having different molecular weights in combination, and the resin properties finally combined have a glass transition point of 50 to 75.
° C, softening point 80-120 ° C, number average molecular weight 2000-3
0000 and weight average molecular weight / number average molecular weight of 2-2
If it is 0, it can be used preferably. When the glossiness is reduced, the weight-average molecular weight / number-average molecular weight value 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, especially in the case of full-color toner, an epoxy resin can be suitably used. 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.

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 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 the polypropylene wax, which is a polyolefin wax, low molecular weight polypropylene has a low hardness and therefore has a defect of lowering the fluidity of the toner. In order to improve this defect, a carboxylic acid or an acid anhydride is used. Those modified with a substance are preferred. In particular, a modified polypropylene resin obtained by modifying a low molecular weight polypropylene resin with one or more acid monomers selected from the group consisting of (meth) acrylic acid, maleic acid, and maleic anhydride 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 modified polypropylene, the acid value is 0.5-3.
0 KOHmg / g, preferably 1-20 KOHmg / 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.

As the commercially available oxidized polyethylene, there is Sunwax E300 manufactured by Sanyo Chemical Industries.
(Softening point 103.5 ° C, acid value 22), sun wax E2
50P (softening point 103.5 ° C., acid value 19.5), high wax 4053E manufactured by Mitsui Petrochemical Industries, Ltd. (softening point 14
5 ° 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 a microcrystalline one having 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 ester wax refined from minerals, is a fine crystal like carnauba wax, and has an acid value of 1 to 20, preferably 3
~ 15.

Rice wax is obtained by air-oxidizing rice bran wax, and preferably has an acid value of 5 to 30 KOHmg / g.

Fischer-Tropsch wax is a wax that is produced as a by-product when 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.

As the acid value of the Fischer-Tropsch wax, 0.5 to 30 KOH mg / g can be used. Among the sasol waxes, the acid value is particularly 3 to 30 KOH.
Oxidation types having an OH mg / g (trade names, Sasol wax A1, A2, etc.) can be suitably 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 coloring agent, 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. Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 1
7, C.I. I. Solvent Yellow 162, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I. I. Pigment Blue 15: 1,
C. I. Pigment Blue 15: 3 and the like. In the case of a color toner, the amount of the colorant is preferably 2 to 6 parts by weight based on 100 parts by weight of the binder resin. From the viewpoint of improving the dispersibility in the binder resin, the colorant for the color toner is preferably used in the form of a masterbatch that has been previously dispersed and pulverized in a resin having good compatibility with the binder resin to be used. In this case, the masterbatch is added so that the amount of the coloring agent contained is within the above range. In the case of black toner,
The coloring agent is 3 to 15 parts by weight based on 100 parts by weight of the binder resin.
Parts by weight are appropriate. 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 with respect to 100 parts by weight of the binder resin. Parts by weight, more preferably 1 to 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, a part or all of the colorant may be replaced with a magnetic material. Examples of such a magnetic material include magnetite, ferrite, iron powder, nickel and the like. The magnetic substance can be added in an amount of 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, and if the amount exceeds 60 parts by weight, the toner charge amount cannot be stably secured, resulting in deterioration of image quality.

In the toner of the present invention, an additive such as a charge control agent or the above-mentioned wax can be added 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. Acumonium 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 adjusting agent before the surface modification treatment (instantaneous heat treatment) and / or after adjusting the 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. , Various nitrides such as boron nitride, titanium nitride, zirconium nitride, borides such as zirconium boride, oxides, titanium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, silica, colloidal silica, etc. Various oxides, various titanate compounds such as calcium titanate, magnesium titanate, strontium titanate, sulfides such as molybdenum disulfide, fluorides such as magnesium fluoride and carbon fluoride, aluminum stearate, calcium stearate Zinc stearate, various metal soaps such as magnesium stearate, talc, various non-magnetic inorganic fine particles of 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.

As the organic fine particles, styrene-based, (meth) acryl-based, benzoguanamine, melamine, and the like granulated by a wet polymerization method such as an emulsion polymerization method, a soap-free emulsion polymerization method, a non-aqueous dispersion polymerization method, or a gas phase method. Various organic fine particles such as Teflon, silicon, polyethylene, and polypropylene can also be used. The organic fine particles also have a function as a cleaning aid.

Inorganic fine particles having a relatively large diameter such as metal titanate and various organic fine particles may or may not be subjected to a hydrophobic treatment. The amount of the fluidizing agent to be added is 0.1 to 100 parts by weight of the developer particles before the heat treatment.
6 parts by weight, preferably 0.5 to 3 parts by weight are added.
The external addition after the heat treatment is performed in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the developer particles.
It is added in parts by weight, but it is preferable to adjust the amount of addition before and after the heat treatment as appropriate.

The toner of the present invention may be produced by any production method as long as it is prepared so as to have the above average circularity, circularity standard deviation and united particle content. The mixed binder resin, colorant, and other desired additives are mixed and kneaded by a conventional method.
Pulverized and classified to obtain toner base particles having a desired particle size,
It is preferable that the particles obtained as described above be subjected to instantaneous heat treatment with hot air. The volume average particle diameter of the toner base particles before the instantaneous heat treatment is 4 to 12 μm, preferably 5 to 10 μm. The particles obtained at this stage have almost the same particle size distribution even after being subjected to the instantaneous heat treatment. If it is less than 4 μm, it tends to cause a decrease in fluidity and fogging, and if it is more than 12 μm, the resolution is reduced and a high-quality image cannot be obtained.

The classification step may be performed after performing the instantaneous heat treatment. 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 Teabrex type classifier (manufactured by Hosokawa).

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 modification devices include a hybridization system (manufactured by Nara Machinery Co., Ltd.), a Cryptron Cosmos series (manufactured by Kawasaki Heavy Industries, Ltd.), and an innomizer system (manufactured by Hosokawa Micron).
Surface modification equipment using a high-speed impact method in a gas stream, such as a mechano-fusion system (manufactured by Hosokawa Micron), a mechanomill (manufactured by Okada Seiko), etc. A surface modification device to which a wet coating method of Seimei Engineering Co., Ltd.) or Coatmizer (Freund Sangyo Co., Ltd.) is applied can be used in appropriate combination.

In the present invention, the shape of the toner particles obtained by the kneading-pulverization method is controlled to be spherical and uniform by performing the instantaneous heat treatment, and further, the pores on the toner surface are reduced. And smoothness can be improved.
Due to this, the charging uniformity and image performance are excellent,
In addition, it is possible to provide a toner that achieves stable image performance for a long period of time without the occurrence of selective development in which a toner having a specific particle size / shape component in a developer and a toner having a specific charge amount is consumed first. .

In addition, a small particle size containing a binder resin having a low softening point suitable for high image quality, low consumption (color material high filling type) and energy saving fixing system, which is highly demanded in recent years, and having a high number of coloring material parts, is used. In toner, a toner carrier (carrier,
(Developing sleeve, developing roller, etc.), excellent transferability due to adhesion to a photoreceptor, a transfer member, etc., so that 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

In the present invention, the instantaneous heat treatment is preferably performed by dispersing and spraying toner particles in hot air with compressed air, whereby the surface of the developer is modified by heat. Degree and its uniformity can be achieved.

A schematic configuration diagram of an apparatus for performing an instantaneous heat treatment will be described with reference to FIGS. As shown in FIG.
The high-temperature, high-pressure air (hot air) prepared by the hot-air generator 101 is injected from a hot-air injection nozzle 106 through an introduction pipe 102. On the other hand, the toner particles 105
Is transported by a predetermined amount of pressurized air through an introduction pipe 102 ′ and sent into a sample injection chamber 107 provided around the hot air injection nozzle 106.

As shown in FIG. 2, the sample ejection chamber 107 has a hollow donut shape, and a plurality of sample ejection nozzles 2-2 are arranged at equal intervals on the inner wall. The toner particles fed into the sample ejection chamber 107 are diffused and uniformly dispersed in the ejection chamber 107, and the plurality of sample ejection nozzles 2 are continuously supplied by the pressure of the continuously supplied air.
-2 is injected into the hot air stream.

Further, the sample jet nozzle 2-2 is designed so that the jet flow of the sample jet nozzle 2-2 does not cross the hot air stream.
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 to 35 °. Is preferred. If it is wider than 40 °, the toner jet flow will be jetted across the hot air flow,
When the toner particles collide with the toner particles ejected from another nozzle, the toner particles aggregate. On the other hand, when the angle is smaller than 20 °, the toner particles that are not taken into the hot air are generated, and the shape of the toner particles becomes uneven. .

Further, a plurality of sample injection nozzles 2-2 are necessary, 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 the time during which the necessary modification of the toner particles (heat treatment) is achieved and the aggregation of the toner particles does not occur excessively, although it depends on the processing temperature and the concentration of the toner particles in the hot air stream. It is 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 ejecting nozzle and introduced into the introduction pipe 102 ″. Is too much.

Next, the toner particles which have been instantaneously heated are immediately cooled by the cool air introduced from the cooling air introduction unit 108, and adhere to the device wall or agglomerate with each other without passing through the introduction pipe 102 "to the cyclone 109". And collected in a product tank 111. The transport air after the toner particles are collected further passes through a bag filter 112 to remove fine powder, and is then discharged to the atmosphere via a blower 113. Preferably, the cyclone 109 is provided with a cooling jacket through which cooling water flows to prevent aggregation of toner particles.

Other important conditions for performing the instantaneous heat treatment are the amount of hot air, the amount of dispersed air, the concentration of the dispersed air, the processing temperature, the temperature of cooling air, the amount of suction air, and the temperature of cooling water.

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 means the dispersion concentration of the toner particles in the heat treatment region, specifically, in 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 / g.
It is preferable to treat at m ³ , preferably at 50 to 200 g / m ³ .

The processing temperature refers to the temperature in the heat treatment area. In the heat treatment region, a temperature gradient actually exists from the center to the outside, but it is preferable to reduce the temperature distribution for the treatment. From the device side, it is preferable to supply the wind in a stabilized laminar flow state 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, the glass transition point of the binder resin + 100 ° C. or more to the glass transition point + 300 ° C. It is preferable to perform the treatment in the peak temperature range. More preferably, the treatment is carried out in a peak temperature range from the glass transition point of the binder resin + 120 ° C or more to the glass transition point + 250 ° C. In addition,
The peak temperature range refers to the maximum temperature in a region where the toner contacts hot air.

A type of binder resin having a relatively wide molecular weight distribution, for example, a weight average molecular weight / number average molecular weight of 30 to
In a non-magnetic toner using a binder resin having 100, the glass transition point of the binder resin +10
It is preferable to perform the treatment in a peak temperature range from 0 ° C. or higher to the glass transition point + 300 ° C. More preferably, the glass transition point of the binder resin + at least 150 ° C to the glass transition point + 2
Process at a peak temperature range of 80 ° C. 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, unified particles are more likely to be generated than necessary. 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 instantaneous heat treatment, the toner particles are preferably returned to an atmosphere at a temperature lower than the glass transition temperature by cooling air in order to instantly cool the toner particles to a temperature range in which aggregation or coalescence of the toner particles does not excessively 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 an instantaneous heat treatment, in addition to the cooling by the cooling water in the apparatus described below, the time during which the binder resin is in the molten state is extremely short, so that the particles do not adhere to each other and to the walls of the heat treatment apparatus. 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 amount of suction air is the amount of air for conveying the toner particles processed by the blower 113. 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 the cyclones 109 and 11
4 and the temperature of the cooling water in the cooling jacket provided by the introduction pipe 102 ″. The cooling water temperature is 25 ° C. or less, preferably 15 ° C. or less, more preferably 10 ° C.
It is as follows.

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

The amount of toner particles to be supplied into the hot air stream is controlled to be constant, and no pulsation or the like is generated. For this purpose: (i) In Table 1, a table feeder and a vibrating feeder used at 115 in FIG.
Improve quantitative supply. If a high-precision quantitative supply can be performed using a table feeder and a vibration feeder, it is possible to connect the pulverization or classification process and supply the toner particles to the heat treatment process online as it is; (ii) After supplying the toner particles with the compressed air and before supplying the toner particles into the hot air, the toner particles are re-dispersed in the sample supply chamber 107 to improve the 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. For this purpose: (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 uniformity of dispersion of the toner particles dispersed from each nozzle; (ii) the toner particles in the hot air flow are improved. In order to make the dispersion density uniform, the number of nozzles should be at least three or more, preferably four or more, as described above, and should be arranged symmetrically with respect to the entire circumferential direction. The toner particles may be supplied uniformly from a slit provided in the entire 360-degree peripheral area;

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. . For this purpose: (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, the apparatus configuration illustrated in FIG. 1 is an open system, and therefore, the hot air tends to diffuse in a direction in contact with the outside air, so that the hot air supply port may be restricted as needed;

The toner particles have been subjected to a fluidization treatment so as to maintain a uniform dispersion state during the heat treatment. For this purpose: (i) BE to ensure dispersion and fluidity of toner particles;
T specific surface area is 100 to 350 m ² / g, preferably 13
0-300 m ² / g of inorganic fine particles (first inorganic fine particles) are used. It is preferable that the inorganic fine particles have been subjected to a hydrophobic treatment with a known hydrophobic agent. The addition amount of the inorganic fine particles is 0.1 to 6 parts by weight based on 100 parts by weight of the toner particles,
Preferably it is 0.3 to 3 parts by weight. (Ii) It is preferable that the mixing treatment for improving the dispersion / fluidity exists uniformly and strongly adhered to the surface of the toner particles without being fixed.

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 are present 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 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 a spacer effect is provided between the toner particles, and aggregation and aggregation of the toner particles are performed. Prevent coalescence;

(Ii) To achieve such an effect
Has a BET specific surface area of 10 to 100 m ^Two/ G, preferably
Is 20-90m^Two/ G, more preferably 20-80 m^Two/
g of inorganic fine particles (second inorganic fine particles). Inorganic fine particles
The amount of toner added is 0.05 with respect to 100 parts by weight of toner particles.
To 5 parts by weight, preferably 0.3 to 3 parts by weight. What
In addition, the first inorganic fine particles and the second inorganic fine particles described above are used in combination.
The difference between the BET specific surface areas is 30 m^Two/
g or more, preferably 50 m^Two/ G or more
Is preferred.

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. After such an instantaneous heat treatment, the first inorganic fine particles and / or the second inorganic fine particles are fixed to the toner surface. Here, the term “fixed” means that a part of the inorganic fine particles is embedded in the surface of the toner particles and both are integrated.

The toner particles obtained as described above are externally added by mixing a post-treatment agent such as a fluidizing agent to obtain a toner. As the post-treatment agent, inorganic fine particles or organic fine particles can be used. BE as the above post-treatment agent
BET specific surface area of 1 to 350 m ² / g as T specific surface area
It is preferable to use inorganic fine particles of the above.

From the viewpoint of improving the fluidity of the toner,
BET specific surface area of 100-
350m ² / g, preferably used as the 130~300m ² / g. It is preferable that the inorganic fine particles have been subjected to a hydrophobic treatment with a known hydrophobic agent. The addition amount of the inorganic fine particles is 0.1 to 3 parts by weight, preferably 0.3 to 1 part by weight, based on the toner particles.

Further, from the viewpoint of improving the environmental stability and the durability stability of the toner, the BET specific surface area is preferably 1 to 100 m ² / g, preferably 5 as inorganic fine particles for post-treatment.
９０90 m ² / g, more preferably 5 to 80 m ² / g. The amount of the inorganic fine particles is 0.5 to 5 parts by weight, preferably 0.3 to 2 parts by weight, based on the toner particles. When the above-mentioned inorganic fine particles for improving fluidity and inorganic fine particles for improving stability are used in combination, the BE
Difference T specific surface area of 30 m ² / g or more, preferably 50 m ²
/ G or more.

As described above, it is preferable that the toner of the present invention is manufactured by the above-described series of steps so as to have the above-mentioned average circularity, circularity standard deviation and united particle content. By manufacturing in a series of processes, the composition of toner particles and coalesced particles can be the same, and the chargeability, uniformity and stability of fixation can be improved compared to the case where amorphous toner formed by different methods is mixed with spherical toner. Excellent.

The toner of the present invention obtained as described above is subjected to a full-color image forming method, preferably, a press transfer of a toner image formed on an image carrier onto an intermediate transfer body for each color. Thereafter, the toner image is effectively used in a full-color image forming method including pressing and transferring the toner image transferred onto the intermediate transfer member onto a recording member. That is, in the full-color image forming method using the toner of the present invention, the toner image does not drop out or the toner scatters during the primary and secondary transfer, no image fogging occurs in the full-color copy image, and the transferability is improved. Excellent cleaning properties. Further, when the one-component developing method is applied, toner selection (shape particle size, etc.) on the toner carrier does not occur, and a stable image can be obtained for a long period of time. Further, since the toner of the present invention obtained by performing the instantaneous heat treatment has a high toner shape and a high surface smoothness, it is strong against stress, and can reduce burial of a post-treatment agent and generation of fine powder due to cracking of the toner. Further, appropriate convex portions for improving the chargeability of the toner are formed by pre-processing or post-processing. These are low-temperature fixability, OH
This shows that the required performance (quality) can be improved even by using a resin having a low softening point that can cope with P light transmission.

Further, the operating window can be expanded to increase the system speed and the life of an image forming apparatus such as a printer.

A full-color image forming method using the toner of the present invention will be described with reference to a known full-color image forming apparatus shown in FIG. In the following full-color image forming apparatus, a photosensitive member is used as an image carrier, an endless intermediate transfer belt is used as an intermediate transfer member, and a sheet-like recording paper is used as a recording member.

Referring to FIG. 3, a full-color image forming apparatus generally includes a photosensitive drum 1 driven to rotate in the direction of arrow a.
0, the laser scanning optical system 20, and the full-color developing device 3
0, an endless intermediate transfer belt 40 that is driven to rotate in the direction of arrow b, and a paper feed unit 60. Around the photosensitive drum 10, a charging brush 11 for charging the surface of the photosensitive drum 10 to a predetermined potential and a cleaner 12 having a cleaner blade 12a for removing toner remaining on the photosensitive drum 10 are further provided. is set up.

The laser scanning optical system 20 is a well-known type having a built-in laser diode, polygon mirror, and fθ optical element, and its control unit includes C (cyan), M (magenta),
Print data for each of Y (yellow) and Bk (black) is transferred from the host computer. The laser scanning optical system 20 sequentially outputs print data for each color as a laser beam, and scans and exposes the photosensitive drum 10. As a result, an electrostatic latent image for each color is sequentially formed on the photosensitive drum 10.

The full-color developing device 30 includes Y, M, C, and B
4 containing a one-component toner composed of k non-magnetic toners
The three color developing devices 31Y, 31M, 31C, and 31Bk are integrated, and can be rotated clockwise about the support shaft 81 as a fulcrum. Each developing device includes a developing sleeve 32 and a toner regulating blade 34. Developing sleeve 32
The toner conveyed by the rotation of the roller is charged by passing through a pressure contact portion (gap) between the blade 34 and the developing sleeve 32.

The positions of the developing devices for accommodating the yellow toner, the magenta toner, the cyan toner, and the black toner may be determined based on whether the full-color image forming apparatus is for the purpose of copying a line diagram image such as a character or a photograph. It depends on whether the purpose is to copy a shaded image of each color such as a picture, etc. For example, when the purpose is to copy a line diagram image such as a character, gloss (gloss) is used as a black toner. When using something that does not have
When the black toner layer is formed on the top of the full-color copy image, a sense of incongruity occurs. Therefore, it is preferable to load the black toner into the developing device so that the black toner layer is not formed on the top of the full-color copy image. In this case, it is most preferable that the black toner layer is formed on the intermediate transfer body at the time of primary transfer so that the black toner layer is formed on the lowermost position on the copy image. Will be loaded. At this time, the yellow toner, the magenta toner, and the cyan toner (color toner) may be arbitrarily loaded into the developing device so that the formation order of each layer in the primary transfer is any one of the first to third layers. .

The intermediate transfer belt 40 includes support rollers 41, 4
2 and endlessly stretched over the tension rollers 43 and 44, and are driven to rotate in the direction of arrow b in synchronization with the photosensitive drum 10. A projection (not shown) is provided on a side portion of the intermediate transfer belt 40. By detecting the projection by the microswitch 45, image forming processes such as exposure, development, and transfer are controlled. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 46 and is in contact with the photosensitive drum 10. The contact portion is a primary transfer portion T _1. The intermediate transfer belt 40 is in contact with a rotatable secondary transfer roller 47 at a portion supported by the support roller 42. The contact portion is a secondary transfer portion T _2.

Further, a cleaner 50 is provided in a space between the developing device 30 and the intermediate transfer belt 40. The cleaner 50 has a blade 51 for removing residual toner on the intermediate transfer belt 40. The blade 51 and the secondary transfer roller 47 can contact and separate from the intermediate transfer belt 40.

The paper supply unit 60 includes a paper supply tray 61 that can be opened to the front side of the image forming apparatus main body 1, a paper supply roller 62,
And a timing roller 63. The recording sheets S are stacked on a paper feed tray 61, fed one by one to the right in the drawing by the rotation of a paper feed roller 62, and synchronized with an image formed on the intermediate transfer belt 40 by a timing roller 63. To the secondary transfer section. The horizontal conveyance path 65 for the recording sheet is constituted by an air suction belt 66 and the like including the paper feeding section, and a vertical conveyance path 71 provided with conveyance rollers 72, 73, 74 from the fixing device 70 is provided. The recording sheet S is discharged from the vertical conveyance path 71 to the upper surface of the main body 1 of the image forming apparatus.

Here, the printing operation of the full-color image forming apparatus will be described. When the printing operation is started, the photosensitive drum 10 and the intermediate transfer belt 40 are driven to rotate at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

Subsequently, exposure of the cyan image is performed by the laser scanning optical system 20, and an electrostatic latent image of the cyan image is formed on the photosensitive drum 10. This electrostatic latent image is immediately developed by the developing device 31C, and the toner image is transferred onto the intermediate transfer belt 40 in the primary transfer section. Immediately after the completion of the primary transfer, the developing device 31M is switched to the developing unit D, and subsequently, exposure, development, and primary transfer of the magenta image are performed. Further, switching to the developing device 31Y, exposure, development, and primary transfer of the yellow image are performed. Further, the developing device 31
Switching to Bk, exposure and development of the black image, and primary transfer are performed, and the toner image is superimposed on the intermediate transfer belt 40 for each primary transfer.

When the final primary transfer is completed, the recording sheet S is sent to the secondary transfer section, and the full-color toner image formed on the intermediate transfer belt 40 is transferred onto the recording sheet S. When the secondary transfer is completed, the recording sheet S is conveyed to the belt-type contact heat fixing device 70, where the full-color toner image is fixed on the recording sheet S, and
Is discharged to the upper surface of the

The toner of the present invention employs a one-component developing method in which the developing device passes the pressure contact portion between the toner regulating blade and the developing sleeve to charge the toner as described above, or a carrier. Even if a two-component developing method in which the toner is charged by friction with the toner is adopted, the toner can be effectively used. Generally, the stress applied to the toner particles is greater in the one-component development system than in the two-component development system, so that the toner used in the one-component development system needs to have higher stress resistance than the toner used in the two-component development system. Is done. Further, the toner of the present invention has a development method of contact development,
It can be suitably used in any case of non-contact development.

Further, the toner of the present invention is effectively used in both non-magnetic and magnetic developing systems, but is preferably used in a non-magnetic one-component developing system. The toner of the present invention has a high sphericity, and the surface smoothness is improved by performing the above-described instantaneous heat treatment, so that the toner has excellent stress resistance. This is because the non-magnetic development method is suitable for color copying. Further, the toner of the present invention is suitably used in an image forming apparatus using the above-described cleaning blade as a cleaning unit. This is because, in the present invention, slippage of toner particles in the cleaning blade can be effectively prevented by the contained coalesced particles.

[0099]

EXAMPLES (Production of 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 placed in a mantle heater. Molar ratio Bisphenol A-EO adduct 5 Bisphenol A-PO adduct 5 Terephthalic acid 4 Fumaric acid 5 were charged so as to have the indicated molar ratio, and 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, and the number average molecular weight Mn was 4,800, and the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn was calculated. 3.
9. Polyester resin A having a glass transition temperature of 61 ° C and a softening temperature of 102 ° C was obtained.

(Production of Polyester Resin B) First, a polyester resin b1 was produced. Glass 4 fitted with thermometer, stirrer, falling condenser and nitrogen inlet tube
Polyoxypropylene (2,2)-
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 b1 is 110
℃, glass transition point is 60 ℃, acid value is 17.5 KOHmg
/ G.

Next, a polyester resin b2 was produced. Styrene and 2-ethylhexyl acrylate were adjusted to a weight ratio of 17: 3.2 and placed in a dropping funnel together with digmyl peroxide as a polymerization initiator. on the other hand,
In a glass four-necked flask equipped with a thermometer, a stirrer, a falling condenser and a nitrogen inlet tube, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene ( 2,2)-
2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid,
2,4-benzenetricarboxylic acid and acrylic acid were adjusted to a weight ratio of 42: 11: 11: 11: 8: 1 and added together with dibutyltin oxide as a polymerization initiator. While stirring this at 135 ° C. under a nitrogen atmosphere in a mantle heater, styrene or the like was dropped from a dropping funnel,
The temperature was raised and reacted at 230 ° C. The obtained polyester resin b2 has a softening point of 150 ° C. and a glass transition point of 62.
° C, the acid value was 24.5 KOHmg / g. The resin b1 and the resin b2 were dry-mixed with a Henschel mixer at a weight ratio of 5: 5 to obtain a polyester resin B.

(Production of Magenta Masterbatch) Polyester Resin A (Tg: 61 ° C., Tm: 102 ° C.) 70 parts by weight Magenta pigment (CI Pigment Red 184) 30 parts by weight A mixture having the above composition was kneaded under pressure. And kneaded. After cooling the obtained kneaded material, it was pulverized with 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 (Biscol TS200; Sanyo Chemical Industries, Ltd.) 2 parts by weight After thoroughly mixing the material having the above composition with a Henschel mixer, the mixture was melt-kneaded with a twin-screw extruder (PCM-30; manufactured by Ikegai Iron Works Co., Ltd.) with a larger diameter nozzle at the outlet. Then, the obtained kneaded material was rapidly cooled, and then coarsely pulverized with a feather mill. The crushed material is jet-milled (I
DS; manufactured by Nippon Pneumatic Industries Ltd.), and then classified by a DS classifier (manufactured by Nippon Pneumatic Industries Ltd.) to obtain toner base particles 1 having a volume average particle size of 8.2 μm.

(Toner Base Particles 2) The crushed product obtained in the same manner as the method for producing the toner base particles 1 is crushed and coarse-powder-classified by a counter jet mill (type 100AFG; manufactured by Hosokawa Micron Corporation), and then a rotor classifier ( (Tipplex: Type 100 ATP; manufactured by Hosokawa Micron Co., Ltd.) to obtain toner base particles 2 having a volume average particle diameter of 6.3 μm.

(Toner mother particles 3) 100 parts by weight of polyester resin B 8 parts by weight of carbon black (Mogal L; manufactured by Cabot) 3 parts by weight of zinc salicylate metal complex (E84; manufactured by Orient Chemical Industry) 3 parts by weight of oxidized low molecular weight polypropylene ( (Viscol TS200; manufactured by Sanyo Chemical Industries, Ltd.) 2 parts by weight Toner base particles 3 having a volume average particle diameter of 8.2 μm were obtained in the same manner as in the method of manufacturing toner base particles 1 except that the material having the above composition was used. .

In the following Examples and Comparative Examples, a toner is manufactured using the above toner base particles. In Examples and Comparative Examples, “Pretreatment x” and “Heat treatment condition y” are the following pretreatments. , Heat treatment conditions.

(Pretreatment 1) Hydrophobic silica TS500 (manufactured by Cabosil, BET specific surface area: 225 m ² / g) 0.5 part by weight Hydrophobic silica NAX50 (manufactured by Nippon Aerosil, based on 100 parts by weight of toner base particles) a specific surface area of 40 m ² / g) and 0.3 parts by weight was added, the peripheral speed using a Henschel mixer 30 m / se
The mixing process was performed for 90 seconds at c. (Pretreatment 2) 0.2 parts by weight of hydrophobic silica TS500 (manufactured by Cabosil) 0.3 part by weight of hydrophobic silica NAX50 (manufactured by Nippon Aerosil Co.) was added to 100 parts by weight of the toner base particles, and a Henschel mixer was added. Circumferential speed 30m / se
The mixing process was performed for 90 seconds at c.

(Pretreatment 3) Hydrophobic silica R974 (manufactured by Nippon Aerosil Co., Ltd., BET specific surface area: 170 m ² / g) 0.2 part by weight with respect to 100 parts by weight of toner base particles Hydrophobic silica NAX50 (manufactured by Nippon Aerosil Co., Ltd.) 0.3 parts by weight, and a peripheral speed of 30 m / sec using a Henschel mixer.
The mixing process was performed for 90 seconds at c. (Pretreatment 4) 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.) was added to 100 parts by weight of the toner base particles, and a Henschel mixer was added. Circumferential speed 30m / se
The mixing process was performed for 90 seconds at c.

(Pretreatment 5) Hydrophobic silica TS500 (manufactured by Cabosil) 0.6 part by weight Hexamethyl was added to silica 90G (BET specific surface area 70 m ² / g; manufactured by Nippon Aerosil Co., Ltd.) based on 100 parts by weight of toner base particles 0.3 parts by weight of a 10% surface-treated 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 6) 1.0 part by weight of 10% surface-treated hexamethyldisilazane in silica 90G (BET specific surface area: 70 m ² / g; manufactured by Nippon Aerosil Co., Ltd.) is added to 100 parts by weight of the toner base particles. Peripheral speed 30m / sec using a Henschel mixer
The mixing process was performed for 90 seconds at c.

(Pretreatment 7) 1.5 parts by weight of hydrophobic silica TS500 (manufactured by Cabosil) was added to 100 parts by weight of the toner base particles, and the peripheral speed was 30 m / sec using a Henschel mixer.
The mixing process was performed for 90 seconds at c. (Pretreatment 8) 0.1 parts by weight of hydrophobic silica TS500 (manufactured by Cabosil) is added to 100 parts by weight of the toner base particles, and the peripheral speed is 30 m / sec using a Henschel mixer.
The mixing process was performed for 90 seconds at c.

(Heat treatment condition 1) Maximum temperature: 250 ° C., residence time: 0.5 second, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 18 ° C., cooling water temperature: 10 ° C. (Heat treatment condition 2) Maximum temperature; 200 ° C, residence time;
5 seconds, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 1
8 ° C, cooling water temperature 10 ° C. (Heat treatment condition 3) Maximum temperature; 320 ° C, residence time;
5 seconds, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 1
8 ° C, cooling water temperature 10 ° C.

(Heat treatment condition 4) Maximum temperature: 300 ° C., residence time: 0.5 second, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 18 ° C., cooling water temperature: 10 ° C. (Heat treatment condition 5) Maximum temperature; 350 ° C, residence time;
5 seconds, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 1
8 ° C, cooling water temperature 10 ° C. (Heat treatment condition 6) Maximum temperature; 170 ° C, residence time;
5 seconds, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 1
8 ° C, cooling water temperature 10 ° C. (Heat treatment condition 7) Maximum temperature; 420 ° C, residence time;
5 seconds, powder dispersion concentration: 100 g / m ³ , cooling air temperature: 1
8 ° C, cooling water temperature 10 ° C.

(Production of Strontium Titanate Particles A1) Titanium oxide and strontium carbonate were sintered, and BE
Strontium titanate particles A having a T specific surface area of 9 m ² / g were obtained. The particles A are subjected to a strontium carbonate elution treatment in a hydrochloric acid solution, washed, dried, and surface-treated with 0.5% by weight of n-butyltrimethoxysilane by a dry method to obtain hydrophobic strontium titanate particles A1. I got

Example 1 After pretreatment 1 was performed using toner base particles 1, the surface was reformed under a heat treatment condition 1 by a surface reforming apparatus (surfusing system; manufactured by Nippon Pneumatic Industries, Ltd.) shown in FIG. Processing was performed. At this time, when a SEM photograph observation of the toner was performed, silica particles were present in a uniform and dense state on the toner surface. Further, with respect to 100 parts by weight of the toner, hydrophobic silica R972 (manufactured by Nippon Aerosil Co., Ltd., BE
0.5 part of T specific surface area 110 m ^{2 /} g) and 0.3 part of strontium titanate particles A1 were added, and mixed for 180 seconds at a peripheral speed of 30 m / sec using a Henschel mixer. After that, a circular vibrating sieve (opening 77 μm)
To obtain toner A.

Examples 2 to 4, 6 to 9 and Comparative Example 1,
3 , 5 to 6 Toners B to D, FI to J, L, N to O in the same manner as in Example 1 except that the toner base particles, pretreatment, and heat treatment conditions shown in Table 1 were employed. I got

Example 5 and Comparative Example 2 The toner base particles, the pretreatment and the heat treatment conditions shown in Table 1 were employed, and after the surface modification treatment, the volume average particle diameter (D) of 2 was determined by an elbow jet classifier. Toners E and K were obtained in the same manner as in Example 1, except that the toner was classified so that the toner of 2 times (2D) or more became 0%.

Comparative Example 4 The toner base particles 1 were used as they were without performing the pretreatment.
The surface reforming apparatus shown in FIG. 1 (surfing system;
The surface modification treatment was performed under heat treatment condition 6 by Nippon Pneumatic Industries, Ltd.). Further, 0.5 parts of hydrophobic silica R972 (manufactured by Nippon Aerosil Co., Ltd.) and 0.3 parts of strontium titanate particles A1 were added to 100 parts by weight of the toner, and the peripheral speed was 30 m using a Henschel mixer.
/ Sec for 180 seconds. Thereafter, the mixture was sieved with a circular vibrating sieve (opening: 77 μm) to obtain toner M.

A volume average particle diameter (D) of the obtained toner and a content ratio of twice (2D) or more of the volume average particle diameter (D) were determined by using a Coulter Multisizer (manufactured by Coulter Counter Co., Ltd.).
Was measured at an aperture diameter of 50 μm. The average circularity of the obtained toner and the standard deviation (SD) of the circularity
Was measured by a flow-type particle image analyzer (FPIA-1000; Toa Medical Electronics Co., Ltd.). The results are summarized in Table 1.

Further, the content ratio (number%) of coalesced particles in each of the obtained toners was determined by a flow type particle image analyzer (F
PIA-2000; manufactured by Toa Medical Electronics Co., Ltd.). This device shoots about 3000 toner particles arbitrarily selected from the input toner one by one,
It has a function of measuring the particle size of individual toner particles from each photographed image and classifying each photographed image into classes according to a predetermined particle size range. Using this apparatus, measurement was performed according to the following procedure.

First, the number of coalesced particles is counted from about 1.5% of the total number of photographed images of the total number of particles of the class (class 5) having a particle size of 10 μm or more and less than 20 μm. The number of coalesced particles in all the particles contained in was calculated. Similarly, the number of coalesced particles is counted from about 10% of the total number of photographed images of the total number of particles in the class (class 6) having a particle diameter of 5 μm or more and less than 10 μm, and the total number included in class 6 is determined from the counted number. The number of coalesced particles in the particles was calculated.

Further, since the base particles having a particle size of 20 μm or more are excluded by the classification step performed before the surface modification treatment, all the toner particles included in the class (class 4) having a particle size of 20 μm or more and less than 40 μm are combined. One particle was considered. Then, the above-mentioned number of coalesced particles included in these classes 4, 5, 6 and these classes 4, 5,
From the total number of particles contained in No. 6, the number ratio of coalesced particles in classes 4, 5 and 6 was determined by the following equation, and this was defined as the union particle content ratio (number%). Note that the number of picked-up images to be selected is not limited to the above, and it is sufficient that the number of coalesced particles included in each class can be converted.

[0122]

(Equation 2)

For example, the total number of particles in classes 4, 5, and 6 is 8, 310, and 1728, respectively, and 45 shot images and 117 shot images are selected from classes 5 and 6, respectively. When the numbers are a and b, the united particle content ratio is as follows: 100 × (8 + 310a / 45 + 1728b / 117)
/ (8 + 310 + 1728).

[0124]

[Table 1]

Evaluations Toners other than the toner I (the toner I was later evaluated as a two-component developer) were evaluated for the following evaluation items. <One-Component Developing Method> (Cleaning) The toner is mounted on a full-color printer (Color Page Pro TMPS: manufactured by Minolta) having the configuration shown in FIG. 3 and a predetermined print pattern having a B / W ratio of 6% is L / L. Continuous copying was performed under an environment (10 ° C., 15%) and an N / N environment (23 ° C., 45%). After copying 10 sheets under the L / L environment (hereinafter referred to as initial) and at the initial stage under the N / N environment and after continuous copying of 2000 sheets (after endurance), visually observe the photoreceptor and the intermediate transfer member. evaluated. The criteria are as follows. 〇: Filming and BS did not occur on the photoreceptor and the intermediate transfer member, and no problem occurred; Δ: Filming and BS occurred on one of the photoreceptor and the intermediate transfer member However, it was not visible on the copied image, and there was no practical problem. ×: Good on the photoreceptor and / or filming and BS occurred on the intermediate transfer member. there were.

(Punching) Continuous copying was performed in the same manner as in the method of evaluating the cleaning property, and the copied images were visually observed at the initial stage in an N / N environment and after continuous copying of 2000 sheets (after endurance).
Escape was evaluated. The criteria are as follows. The amount of toner adhering to the paper is set to 1.0 mg / cm ² (± 0.1) by changing the setting of the bias. ：: no hollowing occurred on the copied image; Δ: slight hollowing occurred on the copied image, but no problem in practical use; ×: many hollowing occurred on the copied image. There was a practical problem.

(Defective regulation-streaks, unevenness) Continuous copying was performed in the same manner as in the evaluation method of the cleaning property, and the state of the sleeve of the developing device and the copied image were initially obtained under N / N environment and after continuous copying of 2000 sheets (after endurance). Was visually observed and evaluated. The criteria are as follows. ：: No streak or unevenness occurred on the sleeve; Δ: Although some streak or unevenness occurred on the sleeve, there was no vertical streak on the copied image and there was no practical problem; ×: On the sleeve Many streaks or unevenness occurred, and there were practical problems such as abnormal noise, toner sticking and toner spilling.

(Image Evaluation—Halftone, etc.) Except that a solid image and a halftone image were used as a copy object,
Continuous copying in the same manner as in the evaluation method of cleaning
The copied image was visually observed and evaluated at the beginning of the environment and after continuous copying of 2000 sheets (after endurance). The criteria are as follows. ：: No streak or unevenness occurred in any of the copied image formed by the solid image and the copied image formed by the halftone image; Δ: A minute streak or unevenness occurred in any of the copied image formed by the solid image and the copied image formed by the halftone image X: There was no problem in practical use; ×: A lot of streaks or unevenness occurred in any of the copied image based on the solid image and the copied image based on the halftone image, and there was a practical problem.

Toner I was mixed with a carrier manufactured as described below so that the toner concentration was 6% by weight.
A component developer was obtained. The developer was evaluated for the following evaluation items. <Two-Component Developing Method> (Cleaning Property) A developer (starter) composed of the toner I and a carrier described below is supplied to a full-color copying machine (CF9).
00: manufactured by Minolta Co., Ltd.), and a document having an image portion of 15% was continuously copied under the L / L environment and the N / N environment.
At the initial stage under the L / L environment, at the initial stage under the N / N environment, and after continuous copying of 50,000 sheets (after endurance), the evaluation was performed by visually observing the photoreceptor. The criteria are as follows. 〇: Filming and BS did not occur at all; Δ: Filming and BS occurred, but were not visible on the image, and there was no practical problem; ×: Filming and BS occurred, and the image was not generated However, it could be confirmed, and there was a practical problem.

(Dropping) Continuous copying was performed in the same manner as in the method of evaluating the cleaning property, and the copied images were visually observed at the initial stage in an N / N environment and after continuous copying of 50,000 sheets (after endurance) to evaluate the dropout. did. The criteria are as follows. The amount of toner adhering to the paper was 1.0 m by changing the bias setting.
g / cm ² (± 0.1). ：: no hollowing occurred on the copied image; Δ: slight hollowing occurred on the copied image, but no problem in practical use; ×: many hollowing occurred on the copied image. There was a practical problem.

(Halftone) Continuous copying was performed in the same manner as in the evaluation method of the cleaning property, except that a solid image and a halftone image were used as the copy object. After (durability), the copied image was visually observed and evaluated. The criteria are as follows. ：: No streak or unevenness occurred in any of the copied image formed by the solid image and the copied image formed by the halftone image; Δ: A minute streak or unevenness occurred in any of the copied image formed by the solid image and the copied image formed by the halftone image X: There was no problem in practical use; ×: A lot of streaks or unevenness occurred in any of the copied image based on the solid image and the copied image based on the halftone image, and there was a practical problem.

Table 2 shows the results of these evaluations.

[Table 2]

(Manufacture of Carrier) Capacity 500 equipped with a stirrer, condenser, thermometer, nitrogen inlet tube and dropping device
100 parts by weight of methyl ethyl ketone was charged into a ml flask. Methyl methacrylate 3 at 80 ° C under nitrogen atmosphere
6.7 parts by weight, 5.1 parts by weight of 2-hydroxyethyl methacrylate, 58.2 parts by weight of 3-methacryloxypropyltris (trimethylsiloxy) silane and 1,
A solution obtained by dissolving 1 part by weight of 1′-azobis (cyclohexane-1-carbonitrile) in 100 parts by weight of methyl ethyl ketone was dropped into the reactor over 2 hours and aged for 5 hours. To the obtained resin, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.1) was used as a crosslinking agent.
%) Is adjusted so that the OH / NCO molar ratio becomes 1/1, and then diluted with methyl ethyl ketone to obtain a solid ratio of 10% by weight.
Was prepared.

Fired ferrite powder F-300 as core material
(Volume average particle size: 50 μm, manufactured by Powder Tech), and the above coating resin solution was applied and dried with a spira coater (manufactured by Okada Seiko Co., Ltd.) so that the amount of coating resin with respect to the core material was 1.5% by weight. . The obtained carrier was calcined at 160 ° C. for 1 hour in a hot-air circulation oven. After cooling, the ferrite powder bulk was
The mixture was crushed using a sieve shaker equipped with a 5 μm screen mesh to obtain a resin-coated carrier.

The measuring method is described below. (Measurement method of glass transition point (Tg) of resin) Using a differential scanning calorimeter (DSC-200: manufactured by Seiko Instruments Inc.),
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 taken as the glass transition point. (Method of measuring 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), pressurization 20 kg / c
The softening point was defined as the temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when a sample of 1 cm ³ was melted and flowed out under the conditions of m ² and a heating rate of 6 ° C./min.

(Method of measuring acid value) The acid value was determined by dissolving 10 mg of a sample in 50 ml of toluene and using a mixed indicator of 0.1% bromthymol blue and phenol red.
It is a value calculated by titration with a previously standardized N / 10 potassium hydroxide / alcohol solution and the consumption amount of the N / 10 potassium hydroxide / alcohol solution.

(Method of measuring number average molecular weight and weight average molecular weight) The number average molecular weight and weight average molecular weight were measured by gel permeation chromatography (807-IT:
The measurement was performed using JASCO Corporation,
℃, tetrahydrofuran as a carrier solvent 1
Flow at 0 kg / cm ³ , dissolve 30 mg of the sample to be measured in 20 ml of tetrahydrofuran, and dissolve 0.5 mg of this solution.
Was introduced together with the above-mentioned carrier solvent, and determined in terms of polystyrene. (Measurement Method of Toner Volume Average Particle Size) The volume average particle size of the toner was measured using a Coulter Multisizer 2 (manufactured by Coulter Counter).

[0138]

According to the present invention, it is possible to provide an electrostatic latent image developing toner having excellent cleaning properties, charging stability and transfer properties. The toner of the present invention is effective in an image forming apparatus employing either a one-component or two-component developing method. The toner of the present invention can provide a copied image free from image noise such as hollow, streak, and unevenness for a long period of time.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration diagram of an apparatus for performing an instantaneous heat treatment.

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

FIG. 3 is a schematic configuration diagram of a full-color image forming apparatus.

FIG. 4 is an electrophotograph showing the particle structure of the toner of the present invention having a high average circularity.

FIG. 5 shows an electrophotograph showing the particle structure of the coalesced particles.

FIG. 6 shows an electrophotograph showing the particle structure of the aggregated particles.

[Explanation of symbols]

101: Hot air generator, 102, 102 ', 102 ":
Introducing tube, 103: sample injection nozzle, 104: fixed amount supply device, 105: toner particle, 106: hot air injection nozzle, 1
07: injection chamber, 108: cooling air introduction part, 109: cyclone, 111: product tank, 112: bag filter,
113: Blower.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Anno 2-3-113 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Minoru Nakamura Azuchi-cho, Chuo-ku, Osaka-shi, Osaka Osaka International Building Minolta Co., Ltd. (72) Inventor Hiroyuki Fukuda 2-3-1-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka

Claims (7)

[Claims] 1. A method according to claim 1, wherein the volume average particle diameter is 4 to 12 μm, the average circularity is 0.96 or more, the circularity standard deviation is 0.040 or less, and 1 to 10% by number of united particles are contained. Characteristic toner for developing electrostatic latent images. 2. A toner base particle obtained by mixing, kneading and pulverizing at least a colorant and a binder resin, is obtained by instantaneously heating with hot air, has a volume average particle diameter of 4 to 12 μm, and has an average circularity. 0.96 to 1.0, the circularity standard deviation is 0.040 or less,
A toner for developing an electrostatic latent image, which is contained in an amount of 10% by number. 3. The toner for developing an electrostatic latent image according to claim 2, wherein the inorganic fine particles are fixed on the surface of the toner. 4. The electrostatic latent image developing toner according to claim 2, wherein two kinds of inorganic fine particles having different specific surface areas are fixed on the surface of the toner. 5. The toner for developing an electrostatic latent image according to claim 1, wherein the toner is used in a full-color image forming method. 6. The toner for developing an electrostatic latent image according to claim 1, wherein the toner is used for a full-color image forming method using an intermediate transfer member. 7. The toner for developing an electrostatic latent image according to claim 1, wherein the toner is used in a non-magnetic one-component developing system.