JPH05341564A - Toner for heat roller fixation - Google Patents

Abstract

PURPOSE:To provide a small particle sized toner which is obtained by suspension polymerization and has high fixing property jointly with wide non-offset range. CONSTITUTION:The objective toner is a toner for heat roller fixation to develop an electrostatic latent image. In the toner obtained by suspension polymerizing a polymerizable monomer mixed solution, containing a monomer having at least ethylenic unsaturated double bond, a cross-linking agent and a coloring agent, dispersed with a dispersion stabilizing agent in water, the toner for heat roller fixation small in image glossiness in the case of soft roller fixation and having high fixing property and wide non-offset range is obtained by making the gel percentage of the toner 30-80wt.% and making the molecular weight distribution of the THF soluble portion >=10.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to toners for developing electrostatic latent images. In particular, the present invention relates to a polymerized toner in which a toner is directly obtained by polymerizing a monomer composition in a dispersion medium, which has good fixing characteristics and can obtain a high-definition image.

[0002]

2. Description of the Related Art Electrophotography is known as one of various processes for developing an electric or magnetic latent image to form an image and recording the image. In this electrophotographic method, a photoconductive substance is generally used, an electric latent image is formed on a photoconductor by various means, and then this latent image is developed with a toner to form a toner image. The obtained toner image is fixed as it is, or is transferred onto paper or the like and then fixed by means of heating, pressing or the like to form a copy. Various methods such as a powder cloud method, a touch-down method, and a magnetic brush developing method have been proposed as a method of developing using toner, and a method suitable for each image forming process is adopted.

Conventionally, toners used for these purposes are generally obtained by melt-kneading a colorant composed of a magnetic material or a dye / pigment in a thermoplastic resin to uniformly disperse the colorant in the resin, followed by pulverization and classification. By doing so, a toner having a predetermined particle size distribution has been manufactured.

This method of producing a toner by kneading and pulverizing can produce a toner having excellent characteristics, but has certain limitations. That is, it was necessary to use a resin that was easily crushed, in other words, was highly brittle. When a toner using a resin having high brittleness is subjected to actual development, the toner is further pulverized due to the stress of development, and deterioration called selective development or toner spent is likely to occur. In addition, in this kneading-pulverization method, it is difficult to disperse solid fine particles such as a colorant in the resin completely and uniformly, and depending on the degree of dispersion, the composition of the toner is distributed, and the toner development characteristics vary. It may cause

Further, generally, the resolution, the denseness of solid areas, and the gradation reproducibility of an image formed by toner depend largely on the characteristics of the toner, particularly the particle size thereof, and the smaller the particle size, the higher the quality image. Is known to be obtained. Therefore, recent high-quality copying machines and printers often use small particle size toner. However, the production of the small particle size toner by the kneading-pulverization method not only increases the energy cost, but also has the disadvantage that the shape of the toner is irregular and the flowability is poor. A toner having a low fluidity has a problem that a bridge is formed in the toner hopper to make it difficult to replenish the toner, or a complicated device is required to supply the toner. If a large amount of fluidity modifier such as silica fine powder is added to improve fluidity, the fluidity is improved, but another inconvenience such as damage to the photoconductor and large fluctuation of charge amount due to humidity is caused. Cause Therefore, in order to solve the problems of these kneading-pulverizing methods, polymerized toner has been proposed.

[0006]

The suspension polymerization method is known as one of the methods for producing a spherical toner. In the suspension polymerization method, a polymerizable monomer and a colorant, and optionally a polymerization initiator, a cross-linking agent, a charge control agent, and a monomer composition in which other additives are dissolved or suspended are suspended. In a water phase containing a stabilizer, while stirring, the mixture is granulated and polymerized to form toner particles.

The toner produced by this suspension polymerization method is
The particle size can be reduced, and an image with excellent resolution can be provided. However, the image characteristics of the toner need to be well fixed not only during development but also in the final step. In order to apply the toner to a copying machine or a printer of a heat roller fixing method, which is the most general fixing method, it is necessary to satisfy not only high fixability but also offset prevention in particular.

Heretofore, several methods have been known for imparting offset resistance to toner. For example,
As the pulverized toner, a toner using a crosslinked resin is proposed in Japanese Patent Publication No. 51-23354. This method is effective in preventing offset, but on the other hand, there is a problem in that if the degree of crosslinking is increased to such an extent that offset is effective, the fixing rate will decrease. Further, JP-A-56-158340 proposes a toner composed of a low molecular weight polymer and a high molecular weight polymer. This binder resin did not contain a crosslinking component, and its offset resistance was slightly inferior to that of a crosslinked resin.

Further, in JP-A-1-172843 and JP-A-1-225964, a gel content of 0.1
A kneaded-pulverized toner using a binder resin having a peak of -60% and having two peaks in molecular weight has been proposed. With a specific molecular weight distribution and the use of a resin containing a gel component, offset prevention is effective to some extent, but if there is a gel component or a high molecular weight component in the binder resin, a pigment that is a component added to the toner, There is a problem that it becomes difficult to disperse the charge control agent, the release agent and the like in the binder resin by kneading, so that good developing characteristics as a toner cannot be obtained. Further, since the gel content and the high molecular weight component reduce the pulverization efficiency, the pulverization takes a long time, and it is difficult to produce a toner having a small particle size.

Another method has been proposed to prevent offset in polymerized toner. For example 1-5
In 1187, a method is known in which a relatively high molecular weight copolymer is dissolved in a monomer system to produce polymer particles. However, when a high molecular weight polymer is dissolved in a monomer, the viscosity of the monomer mixture becomes high,
Even when dispersed while heating, droplets having a smaller particle size were not obtained, and it was particularly difficult to obtain polymer particles having a small particle size.

Further, Japanese Unexamined Patent Publication No. 63-262660 describes a method for obtaining polymer particles having two peaks by using a redox initiator and an azo initiator in combination. In this method, a peroxide and a reducing agent are used, but when the monomer system contains carbon black or a charge control agent which has a remarkable polymerization inhibiting effect on oxygen radicals, the redox initiator does not act and the desired molecular weight is reduced. There is a problem in that polymer particles having

As a method of broadening the molecular weight distribution of the toner, a method of using a plurality of polymerization initiators having different half-lives is known in addition to the above. However, when an initiator having a long half-life is used, the time required for the polymerization is increased. Not only takes a long time, but the particle size distribution of the particles becomes broad during the polymerization. As a method for preventing offset, a method of producing a toner particle by polymerizing a wax in a monomer is known, but there is a problem in the dispersibility and compatibility of the wax in the monomer, and a small amount is required. No sufficient offset preventing effect was obtained with the above wax, and there was a problem that if the amount of wax added was increased, the fluidity would decrease and image fog would increase. Further, this method has a disadvantage that the scale is remarkably generated in the suspension polymerization tank and the yield is lowered.

An object of the present invention is to provide a toner suitable for hot roller fixing, which is produced by suspension polymerization and has both a high fixing property and a wide non-offset range.
Another object of the present invention is to provide a toner that gives a high-quality image without causing an image formed by soft roller fixing to have gloss. Another object of the present invention is to provide a toner having a small particle diameter and excellent heat roller fixing characteristics, which gives a high-definition image.

[0014]

The present invention has been made to solve the above-mentioned problems, and it is a polymerizable compound containing at least a monomer having an ethylenically unsaturated double bond, a crosslinking agent and a colorant. In a toner obtained by dispersing a monomer mixed solution in water using a dispersion stabilizer and carrying out suspension polymerization, the toner has a gel fraction of 30 to 80% by weight and a THF-soluble portion having a molecular weight distribution of 10%. It is characterized by the above.

[0015]

[Function] In suspension polymerization, the additive is dispersed in the monomer,
Since the monomer droplets are granulated to form the toner particles, there is no inconvenience in cross-linking the toner to enhance the offset resistance unlike the pulverized toner using the cross-linked resin. However, if the proportion of the crosslinking agent is simply increased, the gel fraction will be 100%.
There was a tendency for the fixing rate to drop remarkably as it rose to the vicinity. The present inventors have found that by optimizing the degree of cross-linking and the molecular weight distribution, a small particle size toner having excellent heat roller fixing characteristics can be obtained, and the present invention has been completed.

In order to set the gel fraction of the toner in the optimum range, it is preferable to use a small amount of the cross-linking agent rather than changing the amount of the cross-linking agent to change the radical concentration in the polymerization process to control the degree of polymerization. By changing the radical concentration during the polymerization process, a high-molecular weight component is produced at a low radical concentration and a low-molecular weight component is produced at a high radical concentration, which makes it possible to broaden the molecular weight distribution at the same time.

The degree of crosslinking of the toner is determined by adding a certain amount of a sample to a solvent such as chloroform, separating the insoluble portion with a stainless mesh, drying and then measuring the weight to determine the gel fraction (% by weight). ) As. Gel fraction is 30
-80% is preferable for preventing offset and lowering glossiness, and when the gel fraction is 85% or more, the offset resistance is good but the fixability becomes poor. Conversely, the gel fraction is 30%
If it is less than 1, the image glossiness becomes large, which is not preferable.

As for the molecular weight distribution of the toner, tetrahydrofuran (THF) was used as a solvent, and the portion soluble in THF was gel permeation chromatography (GPC).
Thus, a calibration curve was prepared from monodisperse molecular weight polystyrene, and the polystyrene-reduced molecular weight was determined by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn). The toner has a weight average molecular weight of 100,000 to 500,000 and a number average molecular weight of 0.5 to 20,000, and the molecular weight distribution is preferably 10 or more, more preferably 15 or more. good.

As the oil-soluble polymerization initiator used in the present invention, known polymerization initiators can be used alone or in combination of two or more kinds. For example, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethyl) valeronitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, benzoylper- Polymerization can be carried out using oxides, 2,4-dichloroperoxide, isopropylperoxycarbonate, cumene hydroperoxide, lauroylperoxide type initiators and the like. The amount of these polymerization initiators used is preferably about 0.1 to 5% by weight of the monomer composition. In addition, the amount and timing of addition in two or more stages can be adjusted as desired.
Preferably, 1/10 to 1/3 of the total amount of the initiator is added at the initial stage of the polymerization to form a high molecular weight component, and the remaining amount is added after 1 to 2 hours.

As the cross-linking agent, a cross-linking monomer having two or more unsaturated bonds in one molecule is preferably used and copolymerized. As the crosslinkable monomer, divinylbenzene,
Divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,
Examples thereof include diallyl phthalate. The proportion of these crosslinkable monomers copolymerized with the polymerizable monomers is preferably 0.2 to 2% by weight based on the total amount of the monomers. The amount of the crosslinkable monomer used is 0.2% by weight of the total amount of the monomers.
When it is less than the range, the offset resistance of the toner is low, and the particles are likely to coalesce during the polymerization, resulting in a wide particle size distribution.
On the other hand, if the amount of the crosslinkable monomer exceeds 2% by weight of the total amount of the monomers, the softening temperature of the toner rises and the fixing property deteriorates.

The polymerizable monomer used in the present invention is a radical-polymerizable one and may be used alone or in combination of two or more so that the resulting polymer has the required thermal characteristics and electrostatic characteristics of the toner. It Examples of such monomers include monovinyl aromatic monomers, acrylic monomers, vinyl ester monomers, vinyl ether monomers, diolefin monomers, monoolefin monomers. and so on.

As the monovinyl monomer, styrene, o
-Methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, pn
-Butyl styrene, p-tert-butyl styrene, p
-N-hexyl styrene, pn-octyl styrene,
pn-nonylstyrene, pn-decylstyrene, p
-N-dodecylstyrene, 2,4-dimethylstyrene,
Examples thereof include styrene such as 3,4-dichlorostyrene and its derivatives.

As the acrylic monomer, acrylic acid,
Methacrylic acid, methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, γ-aminoacrylate propyl, stearyl methacrylate, methacrylic Examples thereof include dimethylaminoethyl acid salt and diethylaminoethyl methacrylate.

The vinyl ester-based monomers include vinyl acetate, vinyl propionate and vinyl benzoate, and the vinyl ether-based monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and vinyl phenyl ether. .. Examples of the diolefin monomer include butadiene, isoprene and chloroprene, and examples of the monoolefin monomer include ethylene, propylene, isobutylene, butene-1, pentene-1, 4-methylpentene-1.

Further, by dispersing solid fine particles such as a colorant in the polymerizable monomer and the crosslinkable monomer using a polyester dispersant, the dispersibility is remarkably improved. As a result, the amount of colorant or polar compound exposed on the toner surface is reduced, and it is possible to prevent the deterioration of the charging characteristics, especially in a high humidity environment, and the accompanying scattering and fogging of the toner.

Known dyes and pigments can be used as the colorant. For example, the dyes are nigrosine dye, CI direct red 1, CI direct red 4, CI acid red 1, CI basic red 1, CI solvent red, CI bat red, CI direct blue 1,
CI Direct Blue 2, CI Acid Bull-15, C.
I. Basic Blue 3, CI Solvent Blue, CI Direct Green 6, CI Solvent Red, etc. Examples of the pigment include furnace black, acetylene black, cadmium yellow, Hansa yellow G, naphthol yellow S, pyrazolone red, permanent red 4R, molybdenum orange, fast violet B, phthalocyanine blue, malachite green and phthalocyanine green. It is necessary that these colorants be contained in a ratio suitable for forming a visible image with a sufficient concentration, and usually in a ratio of 2 to 20% by weight based on the total amount of the monomer composition. ..

In order to use the toner as a magnetic toner,
It is also possible to add fine magnetic particles to the monomer composition. Such magnetic materials include powders of ferromagnetic metals such as iron, cobalt and nickel, or chromium in these powders,
A fine powder of an alloy containing manganese, copper, zinc, aluminum, a rare earth element, or the oxide thereof, magnetite, or ferrite is used. The addition amount of these magnetic materials is preferably 20 to 70% by weight based on the total weight of the toner.

When the above monomer composition is suspended in water by a mechanical or ultrasonic homogenizer and polymerized, in order to stabilize the suspended state in water, calcium carbonate, magnesium carbonate, phosphorus is added. It is common to use fine particles of poorly water-soluble inorganic salts such as magnesium acid salt, barium sulfate, silica and alumina as a dispersion stabilizer. In particular, colloidal silica is suitable as a suspension stabilizer for toner because its primary particle size is as small as 10 to 30 nm and the target particle size can be obtained with a smaller amount. These dispersion stabilizers are preferably used in a proportion of 0.01 to 10% by weight with respect to the monomer. In addition to these dispersion stabilizers, small amounts of stabilizing aids may be added. As the dispersion stabilizing aid, water-soluble polymers such as gelatin, carboxymethyl cellulose, starch and polyvinyl alcohol, surfactants and the like can be used.

In the present invention, in addition to the above-mentioned components, additives such as a charge control agent, a fluidity modifier, a cleaning agent and a filler may be added if necessary. Examples of the charge control agent include nigrosine, quaternized ammonium salts, polyalkylamides, molybdic acid chelate pigments, metal complexes of monoazo dyes, naphthenic acid metal salts, and salicylic acid metal complexes. As the fluidity modifier, fine powder of hydrophobic silica, titanium oxide, polyvinylidene fluoride, metal soap and the like is used, and as a cleaning aid, zinc stearate, calcium stearate, magnesium stearate, polymethylmethacrylate is used. Fine powders of rate, nylon, polytetrafluoroethylene, silicon carbide, etc. can be used. These additives may be mixed and dispersed in the monomer composition for use, or may be added to the surface of the resulting toner particles.

[0030]

EXAMPLES The contents of the present invention will be described in more detail below with reference to examples. In addition, the part in an Example and a comparative example represents a weight part.

Example 1 70 parts of styrene, 30 parts of n-butyl methacrylate, 0.2 part of divinylbenzene, 5 parts of carbon black (# 3750 manufactured by Mitsubishi Kasei), polyester-based dispersant (Hypermer LP5 manufactured by ICI). 1 copy,
0.2 parts of a charge control agent (Eisenspiron Black TRH manufactured by Hodogaya Chemical Co., Ltd.) and 1.5 parts of polypropylene (Viscor 660 manufactured by Sanyo Kasei) were mixed and dispersed by an attritor for 6 hours.

Next, 1000 parts of ion-exchanged water aerated with nitrogen gas and 10 parts of finely powdered silica (Aerosil # 130 manufactured by Nippon Aerosil Co., Ltd.) were placed in a container, and the homogenizer was used.
(Nippon Tokushu Kika Kogyo's homomixer) was stirred, and the above monomer composition mixture containing 0.4 parts of azobis 2,4-dimethylvaleronitrile in a dispersion medium was added to the mixture to give 6000 r.
Dispersion granulation was performed at pm for 10 minutes. After replacing the reaction vessel with nitrogen, change to a stirrer equipped with a paddle stirrer, and 200r
While continuing stirring at pm, the temperature was raised to 70 ° C., and after reacting for 1 hour, 1.6 parts of the above-mentioned polymerization initiator was added and reacted for 9 hours. The temperature of the reaction system was lowered to 50 ° C., 20 parts of sodium hydroxide was added, and the mixture was stirred for 4 hours to remove silica fine particles used as a dispersant. The obtained polymer was filtered, washed with water, dehydrated, and dried under reduced pressure at 40 ° C. for 12 hours to obtain a toner.

The particle diameter of the obtained toner was measured with a Coulter counter to find that the volume average particle diameter was 6.5 μm.
In that case, 95% or more of particles having a size of 10 μm or less were contained, and classification operation was unnecessary. The gel fraction determined from the chloroform insoluble content of the toner was 48%, the molecular weight distribution determined by GPC showed two peaks, and the weight average molecular weight was 20.5.
The number average molecular weight was 0.850,000 and the ratio was 24.1.

3 parts of this toner and 97 parts of a ferrite carrier (KBN-100, 53-125 μm manufactured by Hitachi Metals) were mixed to prepare a developer. Negatively charged phthalocyanine OP
Using a reversal development type page printer (400 dpi) using a C photoconductor, a developing machine equipped with a magnet roll of 800 Gauss quadrupole magnetization and a non-magnetic sleeve, a photoconductor surface potential of -800 V, a development gap of 1 mm,
Doctor gap 0.4mm, development bias -400V
Under the developing conditions of No. 3, the image was developed at a speed of 133 mm / s, fixed with a soft roller fixing device, and subjected to image evaluation.

As a result, the average image density of 1.40 (O.
D. ), A high-quality image with less fogging and "dust" in the character part and less gloss was obtained. Blow-off charge is -4
It was 5.8 (μC / g). Furthermore, after printing 10,000 sheets, there is almost no change in image quality, and the contamination of the toner on the carrier surface, that is, the ratio of spent toner, is less than 0.1.
It was extremely small, 2%. Further, the cleaning property of the photosensitive member was also good, and the fixing roller was not stained due to offset. Furthermore, no change was observed in the heat blocking test at 55 ° C. for 24 hours.

Using the toner of Example 1, the minimum fixing temperature and offset resistance temperature were measured. An unfixed image including a solid image portion of 30 mm square was prepared using the printer used previously. Using a 800 W halogen lamp as a heat roller and using a soft roller in which a 1 mm thick silicone rubber elastic layer and a perfluoroalkoxy-4 fluoroethylene copolymer (PFA) layer are coated on a core metal,
The fixing was performed while changing the temperature at a linear pressure of 1.0 kg / cm and a sheet passing speed of 133 mm / sec. Next, the solid image portion whose image density was measured in advance was peeled off with an adhesive tape (made by Scotch), and the lowest temperature at which the difference in density before and after was 95% or more was taken as the lowest fixing temperature and used as an index of fixability. The maximum temperature at which offset does not occur was defined as the offset resistance temperature. As a result, the minimum fixing temperature is 130 ° C and the offset resistance temperature is 220 ° C.
It had high fixability and anti-offset property.

(Example 2) 91 parts of styrene, 9 parts of 2-ethylhexyl acrylate, 0.2 parts of divinylbenzene.
Part, carbon black (Mitsubishi Chemical Industries MA-600)
7 parts, a polyester-based dispersant (polyhexamethylene adipate) 1.0 part, and a charge control agent (Bontron S-34 manufactured by Orient Chemical Co., Ltd.) 1 part were put in a ball mill and mixed for 8 hours. The obtained monomer composition mixture was dispersed in water in the same manner as in Example 1, and 1 part of a polymerization initiator 2,2′-azobisisobutyronitrile was added at the initial stage of polymerization and 2 parts were added after 2 hours. Further, 0.5 part was added after 4 hours for polymerization. Then, by the same method as in Example 1, alkali washing, filtration, water washing, and drying were performed to obtain a toner.

This toner has a volume average particle diameter of 5.5 μm.
Met. The gel fraction was 67%, the weight average molecular weight was 186,000, the number average molecular weight was 10,000, and the ratio was 18.6. Image evaluation was carried out in the same manner as in Example 1 using this toner, and the image density was 1.3.
8 (O.D.), a high-quality image similar to that of Example 1 in which fogging and character dust were extremely small was obtained. When the fixing characteristics were evaluated in the same manner, the minimum fixing temperature was 1
The temperature was 35 ° C., and the offset resistance temperature was 225 ° C.

(Example 3) Two kinds of compositions having the same composition as in Example 2 except that the amount of the cross-linking agent divinylbenzene was changed to 0.1 parts and 0.3 parts with respect to the monomer composition of Example 2. Each monomer mixture was prepared. The mixture of these two types of monomers was made into a suspension by the same method as in Example 2, and then both were added to a polymerization reaction tank to produce polymer particles, thereby obtaining a toner. The obtained toner has a volume average particle size of 6.8.
was μm. Further, the gel fraction of this toner is 45%,
The weight average molecular weight is 145,000 and the number average molecular weight is 0.
It was 780,000 and the ratio was 18.6. When this toner was evaluated in the same manner as in Example 1, the image was good and the minimum fixing temperature was 125 ° C. and the offset resistance temperature was 220 ° C.

Comparative Example 1 A toner was prepared in the same manner as in Example 1 except that 2 parts of the polymerization initiator azobis 2,4-dimethylvaleronitrile was added to the dispersion medium at once. It was manufactured and a toner was obtained. As for the particle diameter of the toner, the volume average particle diameter was 6.0 μm. The gel fraction of this toner was as low as 20%, the molecular weight distribution had one peak, the weight average molecular weight was 125,000, the number average molecular weight was 13,000, and the ratio was 9.6. .. When image evaluation was performed in the same manner as in Example 1, the image density was 1.
The value was 35, but the image gloss was 40, which was too high by the Gardner gloss meter, and the fixing rate was rather low.

Comparative Example 2 A toner was manufactured in the same manner as in Example 3 except that only the monomer composition mixture containing 0.3 part of the divinylbenzene crosslinking agent was used. The volume average particle diameter of the obtained toner particles is 5.2.
was μm. The gel fraction is as high as 85%, and the molecular weight is 253,000 in weight average molecular weight and 0.9 in number average molecular weight.
At 10,000, the ratio was 27.8. When this toner was used to perform an image evaluation in the same manner as in Example 1, the image density was 1.32 and the gloss was small, but the fixing ratio was lowered.

(Comparative Example 3) The same composition and method as in Example 2 were used except that 3.5 parts of the polymerization initiator was added to the monomer mixture at once instead of the method of adding the polymerization initiator in Example 2. A toner was manufactured. The volume average particle diameter of this toner was 7.2 μm. The gel fraction was 34%, the molecular weight by GPC was 96,000, the number average molecular weight was 15,000, and the ratio was 6.4. Image evaluation was carried out in the same manner as in Example 1, and an image density of 1.35 was obtained.
Although an image without fog was obtained, an offset occurred on the image. In a heat-resistant blocking test using a 50 ° C. oven, blocking occurred in 48 hours.

Table 1 shows the minimum fixing temperature and offset resistance temperature of the toners of Examples and Comparative Examples.

[Table 1]

[0044]

The toner for heat roller fixing of the present invention has the constitution and operation as described above, and is excellent in toner fixability and offset resistance in a toner produced by suspension polymerization and has an image density It is possible to provide a toner having a high image quality and a clear image without fog.

[Brief description of drawings]

FIG. 1 shows a relationship between a gel fraction in a toner and an image glossiness according to the present invention.

Front Page Continuation (72) Inventor Hisaya Nakahara 5200 Mikajiri, Kumagaya City, Saitama Hitachi Metals Co., Ltd.

Claims (1)

[Claims] 1. A polymerizable monomer mixed solution containing at least a monomer having an ethylenically unsaturated double bond, a cross-linking agent and a colorant is dispersed in water using a dispersion stabilizer,
In a toner obtained by suspension polymerization, a toner having a gel fraction of 30 to 80% by weight and a THF-soluble portion having a molecular weight distribution of 10 or more, a heat roller fixing toner.