JP3101350B2 - Electrostatic image developing toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a toner for developing an electrostatic charge image in electrostatic printing or the like, and is particularly suitable for a copying machine having a heat roll fixing mechanism for a laser printer or the like.

[0002]

2. Description of the Related Art In electrophotography, an electric latent image is generally formed on a photoreceptor by various means using a photoconductive substance, and then the latent image is developed using a toner. After transferring the powder image onto paper or the like, the image is fixed by heating or solvent vapor to obtain a copy.

As a method for visualizing an electric latent image using toner, a magnetic brush method, a cascade developing method, a powder cloud method, and the like are known. In any of the developing methods, fixing of a toner image is important. Needless to say, this is a process.
Particularly when considering application to a high-speed copying machine, since the toner image and the heat roll come into contact in a heated and molten state at the time of fixing because a heat roll fixing device is used, a part of the toner image adheres to the surface of the heat roll. It is required that there is no transfer, so-called offset.

[0004] Obtaining such an offset-free toner requires more power in a fixing device, and moreover, when considering application to a high-speed copying machine using a heat roll, so-called a labor-saving high-speed copying machine. Meet a difficult problem. That is, the binder polymer used for the toner is required to be as tough as possible and to have a sufficient melt fluidity so that the offset does not occur. However, in order to have melt fluidity, the toner must be heated to a considerably high temperature,
This does not meet the need for labor savings. Therefore, in order to save labor, fixing at a low temperature is required, and it is preferable to use a resin having a low glass transition point and a low molecular weight. However, a resin having a low molecular weight naturally has no toughness and tends to cause offset.

Heretofore, toughening of the toner for preventing offset has generally used a high-molecular polymer having an average molecular weight of about 100,000 or more, especially a vinyl polymer in many cases. In order to fix a toner using a high-molecular-weight vinyl polymer at a low temperature, there are methods such as lowering the glass transition point of the polymer as low as possible without blocking, or lowering the fixing temperature by adding a plasticizer.

However, these methods not only lower the fixing point (the lowest temperature at which complete fixing is performed), but also lower the hot offset temperature (the temperature at which offset starts to occur). The result is that the temperature range between the offset temperatures, the so-called fusing latitude, only moves to the lower temperature side. Also, if an attempt is made to prevent a decrease in the hot offset temperature due to an increase in the weight average molecular weight, the effect of lowering the glass transition point and the addition of a plasticizer is reduced due to the increase in the viscosity of the resin, and further, the pulverization due to a large amount of the crosslinked component With worse sex.

On the other hand, a polyester resin has a low glass transition point, unlike a vinyl polymer, and a resin having a low molecular weight can be easily obtained. This means that a low-temperature fixing toner can be easily obtained.

However, since the polyester resin is a low molecular weight resin, the offset is remarkable and the polyester resin cannot be used as it is for a heat roll toner.

In order to take advantage of the advantages of both the property that the vinyl polymer does not cause an offset up to a high temperature and that the polyester can be fixed even at a low temperature, it is conceivable to blend both resins. No. 54-114245. However, a high-molecular-weight vinyl polymer and a low-molecular-weight polyester resin have poor compatibility between the resins, resulting in a non-uniform dispersion state. In particular, as the molecular weights of the two differ, the compatibility deteriorates, and when the dispersion state is observed with a phase contrast microscope or the like, the dispersion state is observed as if there are islands in the sea. This is also observed when blending poorly compatible plastics. According to the sea-island theory, Plastics, 13, No. 9, 1 (19)
62).

When the above-described sea-island is formed in the toner resin, the other components of the toner, such as a polarity controlling agent such as a dye and a colorant such as carbon black and a magnetic material, become insufficiently dispersed. In the repeated copying, oppositely charged toner and the like are generated, and so-called fogging occurs.

On the other hand, in order to improve the dispersibility of the polyester resin and the vinyl polymer, a method has been proposed in which a common segment is introduced into both to form a graft copolymer. However, such a resin is averaged without taking advantage of each other's advantages of hot offset resistance and low-temperature fixability.

[0012]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a toner which is suitable for a hot roll fixing system and has low heat fixing and excellent offset resistance. In addition, such a toner improves the productivity by increasing the pulverizability at the time of manufacturing, and filming does not occur even in a high-speed system.
It is an object of the present invention to provide a developer having a good balance of fixability, crushability, and filming resistance.

[0013]

According to the present invention, there is provided a toner in which a colorant is dispersed in a binder resin, wherein the binder resin mainly comprises a polyester and a vinyl polymer, and the mixing ratio of the binder resin is a vinyl polymer.
Is 10 to 30% by weight, and the weight
Equivalent molecular weight of 8000 to 20,000, glass transition point of 55
６５65 ° C. and the binder resin is THF
There is no insoluble component, and the molecular weight distribution of the THF dissolved portion by GPC indicates that the weight average molecular weight is 10,000 to 20,000.
0, number average molecular weight of 1,000 to 10,000, 1 × 1
A toner for developing an electrostatic image, characterized in that it contains 0 ⁷ or more components having a molecular weight region 5-15 wt%.

Hereinafter, the present invention will be described specifically.

Conventionally, the balance between the fixing property, the pulverizability, and the hot offset has been achieved by devising the ratio of the crosslinked portion (measured as a THF insoluble portion) and the ratio of the THF soluble portion. The relationship between grindability, fixability and hot offset based on the molecular weight distribution can be determined by dissolving the binder resin in a solvent such as THF so that it can be separated into insoluble and soluble components.
Can be used to measure the molecular weight distribution.

Paying attention to the peak positions and component amounts of the molecular weight distribution of the THF-insoluble portion and the soluble portion, the THF-insoluble portion is disadvantageous to the fixing property but is effective for hot offset.

If the amount of insolubles is too large, the load is too high when kneading the toner with a kneading machine, so that the amount of material supplied must be reduced, which results in poor productivity and problems such as quality fluctuation. .

On the other hand, several patents using a binder resin having a molecular weight range of less than 1 × 10 ⁷ have been filed, but none of them have been satisfactory. As a result of research on these, the following facts were newly discovered regarding the pulverizability and fixing property based on the molecular weight distribution, hot offset and the like.

1. When a binder resin having no THF-insoluble content and having a microgel domain (1 × 10 ⁷ or more molecular weight) is used for the toner, a great effect can be obtained on pulverizability, fixability and hot offset.

2. Weight average molecular weight 8 to improve fixability
By blending a polyester having a glass transition point of 55 to 65 ° C. with a glass transition temperature of 2,000 to 20,000, it is possible to improve the fixability of the vinyl polymer.

3. The binder resin in the toner having the above-mentioned molecular weight range can be obtained by cutting a molecule containing a THF-insoluble component by mechanical energy.

4. At this time, the binder resin component having a molecular weight range of less than 1 × 10 ⁷ has a weight-average molecular weight of 10,000 to 20,000 in view of the balance between fixability and basic image characteristics.
A binder resin having a molecular weight range of 1,000 to 10,000 in terms of the number average molecular weight is preferably 0, and the blend ratio between the vinyl resin and the polyester must include 10 to 30% of the vinyl binder.

5. By adding an epoxy resin to the binder resin composition, fixability is improved.

The above items will be described in more detail.
PC (gel permeation chromatography) is measured as follows. That is, the column was stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) as a solvent was added to the column at this temperature at a rate of 1 / min.
and a THF sample solution of the resin prepared at a sample concentration of 0.05 to 0.6% by weight.
Inject and measure. When measuring the molecular weight of a sample,
The molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, PressureChemica
l Co. Or a molecular weight of 6 × 1 manufactured by Toyo Soda Kogyo Co., Ltd.
0 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ ,
5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.
It is suitable to use 6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ , and to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector. It means to measure the molecular weight distribution of the toner in this manner, but the current column 10 ⁷ or more detection substantially difficult. On the other hand, the existence of a molecular weight range of 10 ⁷ or more, which is the detection limit of GPC molecular weight measurement in the THF soluble portion, that is, a microgel component was discovered, and this molecular range affected the fixability, grindability, and offset. ing. The microgel content can be determined by using a toner separation method. That is, a solvent insoluble in toner is added to THF, and the ratio of THF to the solvent may be determined while observing the molecular weight distribution.

This time, fractionation was performed at 25 ° C. using a mixed solvent of THF and isododecane. The ratio of THF / isododecane is suitably 2 ± 0.5 / 3 ± 1.5, and the liquid in which the toner portion is dissolved at this ratio is the range for measuring the molecular weight of GPC. The THF insoluble matter and the test method for fractionation are measured as follows. About 1.0 g of the toner is weighed, about 50 g of THF is added thereto, and the resultant is left to stand at 20 ° C. for 24 hours.
This is first separated by centrifugation and JIS standard (P3801) 5
Filter at room temperature using a seed C quantitative filter paper. Subsequently, the filter paper residue is an insoluble matter, and is represented by the ratio (wt%) between the used toner and the filter paper residue. Since solids such as carbon are present in this residue, it is separately determined by thermal analysis. In the case of a solvent for separation, THF may be changed to this solvent. The microgel content can be calculated by calculating the THF / isododecane soluble content and the THF insoluble content from the amount of the THF soluble component.

In the vinyl polymer of the present invention, it is preferable to use a vinyl copolymer obtained by polymerizing 50 to 100% by weight, preferably 60 to 90% by weight of styrene. When the styrene copolymerization amount is less than 50% by weight, the heat melting property of the toner is inferior, and as a result, the fixing property tends to be insufficient.

In the present invention, the vinyl monomer other than styrene as a component of the vinyl polymer includes styrene such as α-methylstyrene, p-methylstyrene, p-tert-butylstyrene, p-chlorostyrene and the like. Derivatives,
Methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate , Glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxytriethylene glycol methacrylate,
Methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyl methacrylate Ethyl, N-vinyl-2-pyrrolidone methacrylate, methacrylonitrile, methacrylamide, N-methylol methacrylamide, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, methacrylic acid-
2-hydroxy-3-phenyloxypropyl, diacetone acrylamide, acrylic acid, methyl acrylate,
Ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, acrylic acid Methoxyethyl, propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxyethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxy acrylate Diethylene glycol, phenoxytetraethylene glycol acrylate, benzyl acrylate,
Cyclohexyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxy acrylate, N-vinyl-2-pyrrolidone acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, acrylic 2-hydroxy-3-phenyloxypropyl acid, glycidyl acrylate, acrylonitrile,
A vinyl monomer having one vinyl group in one molecule such as acrylamide, N-methylol acrylamide, diacetone acrylamide, vinyl pyridine or the like is used as a main component. In addition, reaction of divinylbenzene, glycol with methacrylic acid or acrylic acid Products such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate,
Neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate,
Neopentyl glycol hydroxypivalate dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate,
Pentaerythrit trimethacrylate, pentaerythrit tetramethacrylate, trismethacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris (methacryloyloxyethyl) isocyanurate, ethylene glycol diacrylate, 1,3-butylene glycol di Acrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,
6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, hydroxypentyl neopentyl glycol diacrylate, trimethylolethane triacrylate, Trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris (methacryloyloxyethyl) isocyanurate, glycidyl methacrylate and methacrylic acid Or half-esterified acrylic acid, Scan phenol epoxy resin and a semi-ester of methacrylic acid or acrylic acid, using a vinyl monomer having two or more vinyl groups per molecule, such as half esters of glycidyl acrylate and methacrylic acid or acrylic acid.

Among them, preferred vinyl monomers having one vinyl group in one molecule include styrene, styrene derivatives, methacrylic esters, and acrylic esters. Particularly preferred are styrene and alkyl esters of methacrylic acid or acrylic acid having 1 to 5 carbon atoms in the alkyl group.
As the vinyl monomer having two or more vinyl groups in one molecule, divinylbenzene, dimethacrylate of methylene glycol having 2 to 6 carbon atoms, diacrylate and the like are preferable.

These monomers are blended so that the total is 100% by weight.

The radical initiator used for the polymerization of the above monomer or monomer mixture includes benzoyl peroxide,
2-ethylhexyl perbenzoate, lauroyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, 4,4,6-trimethylcyclohexanone Di-tert-butylperoxyketal, cyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide,
Peroxide radical initiators such as cyclohexanone di-tert-butylperoxyketal, 2-octanone di-tert-butylperoxyketal, acetone di-tert-butylperoxyketal, diisopropylbenzene hydroperoxide, 2,2'-azobisisobutyi Lonitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate, There are azobis-based radical initiators such as 1'-azobis (cyclohexane-1-carbonitrile). These are preferably from 0.01 to 20% by weight, particularly preferably from 0.1 to 20% by weight, based on the total amount of the monomers.
Use up to 10% by weight.

At the time of polymerization, butyl mercaptan, octyl mercaptan, dodecyl mercaptan, methyl 2-mercaptopropionate, ethyl 2-mercaptopropionate, butyl 2-mercaptopropionate, octyl 2-mercaptopropionate, pentaerythrite tetra (2-mercaptopropionate), mercaptans such as ethylene glycol di (2-mercaptopropionate) and glycerin tri (2-mercaptopropionate), and halogenated hydrocarbons such as chloroform, bromoform and carbon tetrabromide. It is necessary to use a radical polymerization molecular weight modifier such as These molecular weight modifiers are preferably used in an amount of 0 to 3% by weight based on the total amount of the monomers.

When carrying out aqueous suspension polymerization, partially saponified polyvinyl alcohol, alkyl cellulose, hydroxy-alkyl cellulose, carboxyalkyl cellulose, polyacrylamide, polyvinylpyrrolidone,
Water-soluble polymer dispersants such as polyacrylic acid and its alkali metal salts, polymethacrylic acid and its alkali metal salts,
Insoluble inorganic dispersants such as calcium phosphate, hydroxyapatite, magnesium phosphate, magnesium pyrophosphate, calcium carbonate, barium sulfate, and hydrophobic silica can be used. The dispersant is preferably used in an amount of 0.0001 to 5% by weight based on the aqueous medium in the case of a water-soluble polymer dispersant, and 0.01 to 15% by weight in an aqueous medium in the case of a poorly soluble inorganic dispersant. preferable.

The polyester resin comprises a dihydric alcohol as shown in Group A below and a dibasic acid as shown in Group B, and a tri- or higher alcohol as shown in Group C. Alternatively, a carboxylic acid may be added as a third component.

Group A: ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-
Propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,4
-Bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene (2,
2) -2,2'-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2, 2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane and the like.

Group B: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linolein Acids or esters of these acid anhydrides or lower alcohols;

Group C: trihydric or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid.

In the present invention, a range in which the performance of the toner is not impaired, for example, an epoxy resin, a polyamide resin, a urethane resin, a phenol resin, a butyral resin, a styrene-butadiene resin, or the like, as long as the content is 20% by weight or less in all binders. Good. 5 to 2 especially for epoxy resin
It was found that the fixability was improved by adding 0%. Epoxy resins can be used either unmodified or modified. If it exceeds 20%, the compatibility deteriorates and it cannot be used.

As the epoxy resin used in the present invention, a polycondensate of bisphenol A and epichlorohydrin is representative. Commercial products of such an epoxy resin include EPOMIC R301, EPOMIC R302, EPOMIC R304, EPOMIC R304P and EPOMIC R30.
7, EPOMIC R309, EPOMIC R362, EPOMIC R363, EPOMIC R364, EPOMIC R36
5, EPOMIC R366 and EPOMIC R367 (all manufactured by Mitsui Petrochemical Industries, Ltd.).

Further, there is an epoxy resin having an arbitrary softening point obtained by a polyaddition reaction between a liquid epoxy resin and a bisphenol. Commercially available liquid epoxy resins include EPOMIC R140, EPOMIC R139, EPOMIC R
140P (manufactured by Mitsui Petrochemical Industry Co., Ltd.), etc.
Bisphenols include bisphenol A, bisphenol F, bisphenol AD and the like.

The toner binder resin obtained as described above contains a colorant and / or magnetic powder, and if necessary,
The toner for developing an electrostatic charge image can be obtained by appropriately melting and mixing with a charge control agent and other additives.

As the coloring agent, conventionally known coloring agents such as carbon black, iron oxide pigment, phthalocyanine blue, phthalocyanine green, rhodamine 6G cake, and watching red strontium can be used. Select and use as appropriate within the range.

As the charge controlling agent, nigrosine dye, fatty acid-modified nigrosine dye, metal-containing nigrosine dye, metal-containing fatty acid-modified nigrosine dye, 3,5-di-tert-
A chromium complex of butylsalicylic acid or the like can be used, and is usually used in the toner in an amount of 0 to 20% by weight.

As other additives, silica powder, hydrophobic silica powder, polyolefin, paraffin wax, fluorocarbon compound, fatty acid ester, partially saponified fatty acid ester, fatty acid metal salt and the like can be used. 0 to 10% by weight is used in the toner.

The toner of the present invention can be used for either dry one-component developer or two-component developer. When the one-component toner is used, the magnetic material is a strong magnetic material such as ferrite, magnetite, etc., such as iron, cobalt and nickel. Alloys containing elements that exhibit magnetism, or alloys that do not contain compounds or ferromagnetic elements but become ferromagnetic by appropriate heat treatment, such as manganese and copper such as manganese-copper-aluminum or manganese-copper-tin And an alloy of a type called a Heusler alloy containing chromium dioxide. The magnetic material is uniformly dispersed in the binder resin in the form of a fine powder having an average particle diameter of 0.3 to 30 μm. The content of the magnetic particles is 20 to 70 parts by weight per 100 parts by weight of the toner.
Parts by weight, preferably 40 to 70 parts by weight, are desirable.

The toner composition according to the present invention is made by any of the well-known toner mixing and grinding methods. For example, all the components are mixed in a predetermined amount, mixed and crushed to thoroughly mix all the components, and then the resulting mixture is pulverized. In another known method of forming toner powders, the colorant, resin and solvent are ball milled and the toner formulation mixture is spray dried.

In order to use the toner composition according to the present invention by a cascade developing method, a magnetic brush developing method, an O-shell developing method, or the like, the composition has an average particle size expressed by weight percentage of about 30 μm or less. Must be
It is desirable for this average particle size to be between about 4 and 20 microns for optimal results. Particle sizes slightly less than 1 micron are desirable for use in powder cloud development.

Cascade development method, magnetic brush development method, C
Coated and uncoated carriers, such as those used in shell development methods, are well known, but the carrier particles are brought into intimate contact with the toner particles so that the toner particles adhere to and surround the carrier particles. When
The carrier particles may be formed of any suitable material, provided that the toner powder acquires a charge of the opposite polarity to that of the carrier particles. Accordingly, the toner compositions of the present invention can be used in combination with conventional carriers to develop electrostatic latent images on any suitable electrostatic latent image bearing surface, including conventional photoconductive surfaces. Is done.

As a method for obtaining a component containing 5 to 15% by weight of a component in the microgel region, there is a method in which molecules in the molecular weight region of THF insoluble components are cut by mechanical energy.
According to this method, a mixture of a crosslinked vinyl resin and a polyester having a THF insoluble content of 30 to 70% is mixed with carbon black, a charge control agent, and other additives and kneaded while giving mechanical energy.

In the case of kneading, first, premixing is performed with a kneader such as a V blender or a Henschel mixer, and then a hot roll,
It is kneaded with a kneader such as a pressure kneader, a Hanbury mixer, a single-shaft or twin-shaft continuous kneader. In this kneading, there is a region where molecules are cut by mechanical energy. This is mainly governed by the viscosity during kneading. This viscosity is 10 ⁴ to 10 ⁷
Poise. When kneaded with a viscosity lower than this viscosity range, the molecules are hardly cut and a crosslinked portion remains in the toner. When kneaded with a high viscosity, it does not disperse with other materials. When kneading in the above viscosity range, the amount of the microgel domain varies depending on the amount of cross-linking and the kneading conditions. In other words, it has a feature that a material having a molecular weight in this range can be arbitrarily prepared. This molecular weight cleavage is difficult to obtain synthetically. As a toner characteristic, a molecular weight in this range is effective for hot offset and filming. However, it is disadvantageous for the pulverizability and the fixing property. Therefore, blending with polyester is required to improve the pulverizability and the fixing property.
It became necessary to define the ranges of w and Mn. Mw of 10,000 to 200,000, Mn of 1000 to 200,000
10,000. Outside of this range, problems such as deterioration of the hot offset and the balance between the pulverizability and the fixability occur.

The polyester resin / vinyl resin blend has a sea-island structure of the polyester resin / vinyl resin, but when the vinyl resin is kneaded at 30% or less, there is no practical problem. If it exceeds 30%, poor dispersion of the pigment and the binder resin due to poor compatibility results in deterioration of the dielectric constant and charging characteristics. The polyester resin to be blended has Mw of 8000 to 20,000 and Tg of 55.
It is preferable to use one having a temperature of ~ 65 ° C. When the temperature is lower than 55 ° C., the fixability is improved, but the storage stability and hot offset deteriorate, and when the temperature exceeds 65 ° C., the fixability is not improved. As mentioned above, a polyamide resin or other binder resin may be blended as long as the performance of the toner is not impaired in the present invention as mentioned above. The amount is 20
% Or less. However, 5-20% for epoxy resin
The fixability is improved by blending in the range.

[0051]

EXAMPLES Resin 3 having a mixing ratio shown in the resin conditions in Table 1
00g, carbon black (Mitsubishi Kasei Kogyo Co., Ltd. #
40) 20 parts and 25 g of Oil Black BY (manufactured by Orient Chemical Co., Ltd.) were heated and melt-kneaded with a two-roll mill. Table 1 also shows the kneading conditions.

The obtained kneaded material was roughly pulverized by a hammer mill and finely pulverized by a jet air mill. This was classified and adjusted to a particle size of 10 to 11 μ to obtain a toner. Next, 50 g of each of these toners and EFV200 / 300 (manufactured by Nippon Iron Powder)
950 g, and shaken well to obtain a developer.

Using these developers, evaluation was carried out using a copying machine (FT7500 manufactured by Ricoh). The pulverizability of the toner can be represented by a processing amount of pulverizable toner per unit time. In the case of this toner, the test was performed at an air pressure of 5 kg / cm ² . Table 1 shows the evaluation results.

As is clear from the results, the toner of the comparative example has a poorer balance among the toner characteristics than the toner of the embodiment.

[0055]

[Table 1]

[0056]

The toner of the present invention has a hot offset,
The toner has well-balanced properties in the presence of contradictory properties of fixability, crushability, and filming resistance. Polyester resin has an effect of improving fixability, and by using 10 to 30% by weight of a vinyl polymer,
Hot offset, filming,
Grindability can be improved. The use of an epoxy resin can further improve the fixing property.

Claims (3)

(57) [Claims] 1. A toner comprising a colorant dispersed in a binder resin, wherein the binder resin mainly comprises a polyester and a vinyl polymer, and the binder resin
The mixing ratio is 10 to 30% by weight of the vinyl polymer.
And the weight average molecular weight of the polyester is 8000 to 2
0000, a glass transition point of 55 to 65 ° C., and this binder resin has no THF-insoluble component.
In the molecular weight distribution of the HF dissolved portion by GPC, the weight average molecular weight was 10,000 to 200,000, and the number average molecular weight was 10
A toner for developing an electrostatic image, wherein the toner has a molecular weight of from 1 to 10 and a molecular weight range of 1 × 10 ⁷ or more. 2. An epoxy resin having a binder resin of 5 to 5 times.
The electrostatic image developing toner according to claim 1, wherein the toner is mixed at 20% by weight. 3. A composition having a molecular weight range of 1 × 10 ⁷ or more,
3. The electrostatic image developing toner according to claim 1, wherein the molecular weight is reduced to 15% by weight.