JPH06194875A - Electrostatic charge image developing toner - Google Patents

Abstract

(57) [Summary] [Purpose] Good fixability and excellent offset resistance,
Also, to provide an electrostatic charge image developing toner in which filming and toner spent do not occur even in a high-speed system. In a toner obtained by dispersing a colorant in a binder resin, the binder resin contains 5 to 30% of a component having a THF insoluble content, a molecular weight of 1 × 10 ⁷ or more, and a melting point of 130 to 170. A toner for developing an electrostatic charge image, characterized in that a dispersed particle diameter of a polyolefin wax at ℃ is 2 μm or less.

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. It is also applicable to dry toner for laser printers and other toners used for copying having a heat roll fixing mechanism.

[0002]

2. Description of the Related Art In a toner used in a copying machine having a fixing mechanism for a heating roller, the heating roller surface and the toner image are in contact with each other under pressure in a melted state. A paper offset phenomenon occurs.
As a resin improvement for avoiding the offset phenomenon, Japanese Patent Publication No. 51-23354 proposes a toner using a crosslinked polymer as a binder resin. According to this method, it is effective in improving the offset resistance and the abrasion resistance, but the fixing temperature is sufficiently low, the offset resistance and the abrasion resistance are good, and sufficient fixing characteristics are not obtained. . Further, in the heating roller fixing method, conventionally, in order to prevent the toner from adhering to the surface of the fixing roller, for example, the roller surface is formed of a material having excellent releasability with respect to the toner such as fluorine resin, and the surface of the fixing roller is further coated with silicon. An offset preventing liquid such as oil is supplied to coat the roller surface with a thin film of the liquid.

Although this method is extremely effective in preventing toner offset, it generates an odor when the offset preventing liquid is heated and requires an apparatus for supplying the offset preventing liquid. Therefore, the mechanism of the copying apparatus becomes complicated, and high precision is required to obtain a stable image, so that the copying apparatus becomes expensive.

[0004]

SUMMARY OF THE INVENTION The present invention has the following objects in view of the above-mentioned conventional technique.

1) Providing a toner suitable for a heat roll fixing system, 2) Providing a toner having an excellent hot offset property, 3) Improving pulverizability and pigment dispersibility at the time of production and good productivity. Providing toner, 4) Providing a binder resin with a small power load during toner kneading in a pulverized toner production line.

5) Even if a releasing agent is used, it is difficult to be crushed even if it is repeatedly used in a copying machine for a long time, and it is difficult to fuse to the carrier surface and the sleeve surface of the one-component process, and further, image fogging and toner scattering occur. Provide difficult toner.

[0007]

According to the present invention, a binder resin contained in a toner contains 5 to 30% of a component having a THF insoluble content and a molecular weight of 1 × 10 ⁷ or more,
In addition, the toner for developing an electrostatic charge image is characterized in that a polyolefin wax having a melting point of 130 to 170 ° C. is dispersed at 2 μm or less.

That is, when the toner is kneaded, a binder having a THF insoluble content of 30 to 70%, a polyolefin wax, a pigment and a charge control agent which are other toner components are kneaded as a binder resin, thereby mechanically kneading. The molecules that are insoluble in THF are cleaved by energy, and the insoluble matter in THF is not included.
A toner containing 5 to 30% of a component having an average molecular weight of 10 ⁷ or more is obtained. Further, this toner was kneaded so as to have a main peak in the range of 2000 to 100000 in the molecular weight distribution by GPC of the THF-dissolved component, and the polyolefin wax was dispersed at 2 μm or less as observed by a transmission electron microscope. .

This polymer is a binder resin having a Tg in the range of 55 to 75 ° C., and the toner obtained by using the binder resin provides a toner having well-balanced properties such as hot offset fixability and crushability. The molecular weight distribution of this binder resin is shown in FIG. Of these, a component insoluble in THF and containing 1 × 10 ⁷ or more is called a microgel.

With respect to the above contents, by devising the ratio of the crosslinkable component (measured as the THF insoluble component) and the ratio of the THF soluble component, the relationship between the fixability, pulverizability, hot offset, etc. When it is dissolved in the solvent, it can be separated into an insoluble component and a soluble component, and the soluble component can be measured for molecular weight distribution by GPC.

Focusing on the peak positions and component amounts of the molecular weight distributions of the THF insoluble matter and the soluble matter, the THF insoluble matter works against the fixability but is effective for the hot offset.

If the amount of insoluble matter is too large, the load is too great when kneading the toner in the kneader, so that the amount of material to be supplied must be reduced, resulting in problems such as poor productivity and variability in quality. . Also, 1 × 10 ⁷
Several inventions using a binder resin having a molecular weight range of less than have been proposed, but none of them has resulted in satisfactory results.

On the other hand, the compatibility between the binder resin and the polyolefin wax is poor, and in order to improve this, the amount of the polyolefin wax should be reduced or the molecular weight should be increased. However, if the molecular weight of the polyolefin wax is increased, the compatibility is improved, and although it becomes difficult for the polyolefin wax to be pulverized inside the machine, the releasing effect is reduced.

As a result of research on these, the following facts were newly found regarding pulverizability and fixability based on molecular weight distribution and hot offset. 1. When a binder resin having no THF insoluble content and a molecular weight range of 1 × 10 ⁷ or more is used in the toner, the polyolefin wax as a release agent is effectively dispersed and 2 μm
It is possible to obtain a toner finely dispersed to m or less.

The toner of 2.1 is not easily pulverized in the copying machine. In addition, the pulverizability at the time of manufacture and the fixability as a toner characteristic are not deteriorated, and a great effect can be obtained for filming and hot offset.

The binder resin having a molecular weight range of 3.1 can be obtained by cutting the resin containing a THF-insoluble component by mechanical energy.

4. At this time, a component having a molecular weight range of less than 1 × 10 ⁷ has a weight average molecular weight of 20,000 to 200,000 and a number average molecular weight of 1,000 to 10,000 in view of a balance with fixing property and basic image characteristics. A vinyl-based polymer with a
It is preferably in the range of 55 to 75 ° C.

To obtain the toner of 5.1, the melting point of the polyolefin wax is 130 to 170 ° C., preferably 1
A material having a relatively high melting point in the range of 40 to 160 ° C is preferable.

The above items will be described in more detail.
Regarding the dispersed particle size of the polyolefin in the toner, the toner was dyed with ruthenium tetroxide (RuO ₄ ) for heavy metal to form a thin film, which was observed with a transmission electron microscope and photographed. The dispersed particle size of the polyolefin was measured from the photograph taken.

GPC is measured as follows. That is, stabilize the column in a heat chamber at 40 ° C,
THF as a solvent was added to the column at this temperature at a rate of 1 per minute.
It is made to flow at a flow rate of ml, and 50 to 200 microliters of a THF sample solution of a resin prepared to a sample concentration of 0.05 to 0.6% by weight is injected for measurement. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the function of the logarithmic value and the count number of the calibration curve prepared from several kinds of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure
Chemical Co. Alternatively, the molecular weight manufactured by Toyo Soda Kogyo Co., Ltd. is 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.
75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9
× 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶
It is suitable to use a standard polystyrene sample of at least 10 points. Also, the detector is RI
A (refractive index) detector is used. In this way, the molecular weight distribution of the resin is measured, but it is practically difficult to detect 10 ⁷ or more with the current column. On the other hand, GP is also present in the THF-soluble part.
The existence of a molecular weight region of C having a molecular weight measurement detection limit of 10 ⁷ or more was found, and this molecular region affects the fixability, pulverizability, and offset. 1 × 10 ⁷ in the THF dissolution section
As a method for measuring the above molecular weight range, it can be determined by using a resin separation method. In other words, add a resin-insoluble solvent to THF and check the TH while checking the molecular weight distribution.
The ratio of F and its solvent may be determined. This time, a mixed solvent of THF and isododecane was used, and fractionation was performed at 25 ° C. The ratio of THF / isododecane is 2 ± 0.5 /
3 ± 1.5 is suitable, and the liquid in which the resin portion is dissolved at this ratio is in the GPC molecular weight measurement range. In addition, the THF insoluble fraction and the test method for fractionation are measured as follows. About 1.0 g of resin is weighed, about 50 g of THF is added thereto, and the mixture is allowed to stand at 20 ° C. for 24 hours. First, this is separated by centrifugation and filtered at room temperature using a quantitative filter paper of JIS standard (P3801) Class 5C. Then, the filter paper residue is insoluble,
The ratio (% by weight) of the resin used and the filter paper residue is shown. In the case of a solvent for fractionation, THF may be changed to this solvent. T
The microgel content can be calculated by calculating the THF / isododecane insoluble content and the THF insoluble content from the amount of the HF soluble component.

To obtain the resin for toner of the present invention, for example, a low molecular weight polymer having a weight average molecular weight of 50,000 or less obtained by a two-step polymerization method is synthesized, and (I) 20
The temperature is lowered to below ℃ and the crosslinked polymer (I
Add the monomer for I) and mix well with the core polymer. As a result, the polymer (1) is dissolved in the monomer (II) or adheres around (I). (II)
The monomer for use is obtained by suspension polymerization by adding a crosslinking agent in an amount of 0.2 to 1% by weight based on the total amount of monomers. More specifically, the one-step polymerization is carried out in an aqueous suspension polymerization in a system containing no crosslinking agent. At this time, in order to reduce the molecular weight, it is preferable to use a molecular weight modifier as mentioned in the examples. As a concrete method, a reactor equipped with a stirrer, the above-mentioned monomers,
A reaction initiator, a molecular weight modifier, a dispersant, and ion-exchanged water are charged and suspension polymerization is carried out at 95 to 100 ° C. The reaction is completed in 5 to 8 hours. Next, the temperature is lowered to 20 ° C. or lower. Next, a monomer for two-step polymerization is charged. This monomer and other materials may be the same as in the first stage except that it contains a crosslinking agent. Charge the monomer for the two-stage polymerization at 20 ° C or below
Stir for 4 to 48H. At this time, the total weight ratio of the 1st stage monomer and the 2nd stage monomer is preferably 1st stage / 2nd stage: 3/7 to 8/2. When the number of monomers in the first stage is 3 or less, the target molecular weight of the low molecular weight polymer cannot be obtained, and when it is 8 or more, the polymer in the crosslinked region cannot be obtained. Further, the crosslinkable monomer used in the second stage is preferably 0.2 to 1.0% by weight. If the amount is out of this range, the molecular weight required for kneading the toner cannot be obtained. By stirring at a temperature of 20 ° C. or lower, the one-stage polymer is dissolved in the two-stage polymer or is fused with the one-stage polymer, and the two-stage reaction is performed in 60 to 1
When it is carried out at 00 ° C., it is possible to synthesize one having no crosslinking component and the other having one. A characteristic of the two-step polymerization method is that by synthesizing a low molecular weight region and a high molecular weight component at the resin stage, it is easy to obtain a target molecular weight later by mechanical energy. With this method, a toner having a wider molecular weight range can be obtained as compared with the suspension polymerization in one step. Of course, the resin for toner of the present invention can obtain the target molecular weight of the resin obtained by the one-step polymerization method by mechanical energy, but in this case, the kneading conditions need to be set more severely.

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

In the present invention, the vinyl-based monomer other than styrene, which is a component of the vinyl-based polymer, is styrene such as α-methylstyrene, p-methylstyrene, p-tert-butylstyrene, p-chlorostyrene. Derivative,
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 Oxyethyl, 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, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, acrylic acid Phenoxydiethylene glycol, phenoxytetraethylene glycol acrylate, benzyl acrylate, styrene acrylate Rohekishiru, tetrahydrofurfuryl acrylate, acrylic acid dicyclopentenyl, dicyclopentenyloxyethyl acrylate, N-
Vinyl-2-pyrrolidone, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, glycidyl acrylate, acrylonitrile, acrylamide, N-methylol acrylamide, diacetone acrylamide , Vinyl pyridine, etc. 1
A vinyl monomer having one vinyl group in the molecule is used as a main component, and in addition, a reaction product of divinylbenzene, glycol and methacrylic acid or acrylic acid, for example, ethylene glycol dimethacrylate, 1,3-butylene glycol diester. Methacrylate, 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, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, Limethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, trismethacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris (methacryloyloxyethyl) isocyanurate, ethylene glycol diacrylate, 1 , 3-butylene glycol diacrylate, 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, Dorokishipibarin acid neopentyl glycol diacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate,
Tris (methacryloyloxyethyl) isocyanurate, glycidyl methacrylate and methacrylic acid or acrylic acid half-esterified product, bisphenol type epoxy resin and methacrylic acid or acrylic acid half-esterified product,
A vinyl monomer having two or more vinyl groups in one molecule such as a glycidyl acrylate and methacrylic acid or a half-esterified product of acrylic acid is used.

Of these, a preferable vinyl-based monomer is 1 vinyl-based monomer per molecule, and
In the vinyl monomer having one vinyl group in the molecule,
Examples thereof include styrene, styrene derivatives, methacrylic acid esters, acrylic acid esters, and the like, and styrene and alkyl esters of methacrylic acid or acrylic acid having 1 to 5 carbon atoms in the alkyl group are particularly preferable. Among vinyl monomers having two or more vinyl groups in one molecule, divinylbenzene, dimethacrylate and diacrylate of methylene glycol having 2 to 6 carbon atoms are preferable.

These monomers are blended so that the total is 100% by weight. Among these, the amount of the vinyl-based monomer having two or more vinyl groups in one molecule is preferably 0.1 to 1% by weight.

The above-mentioned monomer or monomer mixture can be polymerized by any method such as suspension polymerization, solution polymerization, emulsion polymerization, bulk polymerization, etc., but the economical efficiency, the stability during production, etc. From the point of view, it is preferably produced by aqueous suspension polymerization.

The radical initiator used in the polymerization of the above-mentioned monomer or monomer mixture is 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,
Cyclohexanone di-tert-butylperoxyketal, 2-octanone di-tert-butylperoxyketal, acetone di-tert-butylperoxyketal, peroxide radical initiators such as diisopropyl pentene hydroperoxide, 2,2′-azobisiso Butyronitrile, 2,2'-azobis (2,4-dimethylpareronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, There are azobis radical initiators such as 1,1′-azobis (cyclohexane-1-carbonitrile). These are preferably 0.01 to 20% by weight, particularly preferably 0.1% by weight, based on the total amount of the monomers.
Use from 1 to 10% by weight.

In addition, during polymerization, butyl mercaptan, octyl mercaptan, dodecyl mercaptan, methyl 2
-Mercaptopropionate, ethyl 2-mercaptopropionate, butyl 2-mercaptopropionate,
Octyl 2-mercaptopropionate, pentaerythritol tetra (2-mercaptopropionate), ethylene glycol di (2-mercaptopropionate),
Radical polymerization molecular weight modifiers such as mercaptans such as glycerin tri (2-mercaptopropionate), halogenated hydrocarbons such as chloroform, promoform, carbon tetrabromide and the like can also be used. These molecular weight modifiers are preferably used in an amount of 0 to 3% by weight based on the total amount of monomers.

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

The toner binder resin obtained as described above is appropriately melt-mixed with a releasing agent, a coloring agent and / or a magnetic powder and, if necessary, a charge control agent and other additives to develop an electrostatic image. Can be used as a toner.

As the coloring agent, carbon black, iron oxide pigment, phthalocyanine blue, phthalocyanine green, rhodamine 6G lake, Watching red strontium, etc., which have been conventionally known, can be used. Select and use the range appropriately.

As the charge control 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 can be used, and it is usually used in an amount of 0 to 20% by weight in the toner.

As the release agent, a polyolefin having a relatively high melting point and various other compounds having a releasing action are used.
Further, it can be contained in combination with the high melting point polyolefin.

Examples of these compounds include cadmium salt, barium salt, lead salt, iron salt, nickel salt, cobalt salt, copper salt, strontium salt, calcium salt or magnesium salt of stearic acid, zinc salt of oleic acid, and manganese. Salt, iron salt, cobalt salt, copper salt, zinc or magnesium salt, zinc salt of palmitic acid, cobalt salt, copper salt, magnesium salt, aluminum salt or calcium salt, zinc salt of linoleic acid, cobalt salt or calcium salt, ricinol Fatty acid metal salts such as zinc salt or cadmium salt of acid, lead salt of caprylic acid, lead salt of caproic acid, polyethylene of relatively low molecular weight, higher fatty acids having 28 or more carbon atoms, natural or commercially available paraffins, ethylene Examples include bis fatty acid amides such as bis stearoyl amide. It can may contain a combination of these compounds alone or in combination. The amount of these compounds added to the toner is generally about 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the resin component of the toner, and these compounds are added to the toner. As a result, the compatibility of the high melting point polyolefin with the resin component is further improved.

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, and these are usually used. Used in toner in an amount of 0 to 10% by weight.

The toner of the present invention can be used as both a dry one-component developer and a two-component developer, and the magnetic substance in the case of one component is a strong magnetic substance such as ferrite, magnetite or the like, iron, cobalt, nickel or the like. An alloy containing an element exhibiting magnetism, or an alloy containing no compound or ferromagnetic element but exhibiting ferromagnetism by proper heat treatment, for example, manganese and copper such as manganese-copper-aluminum or manganese-copper-tin. Examples thereof include alloys of the type called Heusler alloys including and chromium dioxide. The magnetic substance is uniformly dispersed in the binder resin in the form of fine powder having an average particle size of 0.3 to 30 μm. The content of the magnetic particles is 20 to 7 per 100 parts by weight of the toner.
0 parts by weight, preferably 40 to 70 parts by weight is 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 components are mixed in predetermined amounts, mixed, and ground to thoroughly mix all components, and then the resulting mixture is micronized. 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 the cascade developing method, the magnetic brush developing method, the O-shell developing method, etc., the composition has an average particle size represented 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 optimum results. For use in powder cloud development, a particle size of just under 1 micron is desirable.

Cascade development method, magnetic brush development method, O
Coated and uncoated carriers, such as those used in shell development, are well known, but the carrier particles are in intimate contact with the toner powder so that the toner powder adheres to and surrounds the carrier particles. When
The carrier particles may be formed of any suitable material as long as the toner powder acquires a charge of opposite polarity to that of the carrier particles. Accordingly, the toner compositions of the present invention are used in admixture with conventional carriers to develop electrostatic latent images on any suitable electrostatic latent image bearing surface, including conventional photoconductive surfaces. To be done.

Next, a method for obtaining a toner containing 5 to 30% of a microgel component and finely dispersed with a polyolefin wax of 2 μm or less by cutting the molecules insoluble in THF by mechanical energy is shown.

The microgel component has a great effect on the dispersibility of the polyolefin wax. This has a great influence on the rheological properties of the microgel. That is, a high molecular polymer is a substance that exhibits typical viscoelastic behavior. The microgel component has a branched structure formed by cutting molecules insoluble in THF, and is a component having a large molecular weight of 1 × 10 ⁷ or more, so that the storage elastic modulus G ′ during kneading is large. The temperature at the time of kneading the toner is generally in the range of 100 to 200 ° C., but even in this range, the polymer does not flow in the polymer having a branched structure and is at least 10 ⁶ dyn.
It is known that an elastic modulus of about e / cm ² is maintained (Introduction to Rheology P83). Since the elastic modulus relates to the cohesive force of the substance, the polyolefin is kneaded in a state of receiving the cohesive force from the entire toner phase including the microgel, so that strong shearing is applied and the dispersibility is improved.

On the other hand, a system containing no microgel component,
That is, it is known that when a linear polymer is used as a binder resin, the resin flows under general kneading conditions and the elastic modulus tends to zero. In this case, the polyolefin is not sheared and sufficient dispersibility cannot be obtained. When kneading, a resin containing a THF insoluble matter, a polyolefin, a colorant, and various additives are premixed and kneaded with a hot roll, a pressure kneader, a Banbury mixer, a uniaxial or biaxial continuous kneader. In this kneading, there are regions where molecules are cut by mechanical energy. This is mainly controlled by the viscosity during kneading.

The viscosity is 10 ⁴ to 10 ⁷ poise. When kneaded at a viscosity higher than this viscosity range, the molecules are difficult to be cut and the THF insoluble component remains in the resin, resulting in non-uniform dispersion of the polyolefin. Further, when kneading is performed at a viscosity higher than this viscosity range, the mechanical load is large, resulting in over-power and a decrease in material supply. It is more desirable that the kneading temperature is not higher than the melting point of the polyolefin. This effectively applies mechanical shearing to the polyolefin and facilitates fine dispersion of the polyolefin.

THF when kneading in the above viscosity range
The conditions for microgel formation vary depending on the insoluble content and the kneading conditions, but the preferred THF insoluble component is 20 to 70%. Naturally, if the amount of THF insoluble components is small, the amount of microgel is small,
If the dispersibility of the wax becomes insufficient, and if it is too large, the viscosity becomes high and the mechanical load becomes large, so that a sufficient share cannot be obtained, so that the dispersibility of the wax also becomes insufficient. .

The advantage of this method is that the dispersed particle size of the microgel and the polyolefin can be controlled relatively easily. On the other hand, it is difficult to control and control the formation of microgels by polymerization or the like.

As for toner characteristics, the dispersed particle size of the microgel or polyolefin has a great effect on hot offset and filming.

In order to take full advantage of this property, it is necessary to specify the melting point of the polyolefin and the molecular weight of components other than the microgel. That is, as a balance of the amount ratio, the microgel content is 5 to 30%, and the weight average molecular weight of components other than the microgel component is 20,000 to 200,000.
A number average molecular weight of 1,000 to 10,000 is suitable.

Polypropylene is generally used as the polyolefin, but polyethylene, polybutene and the like can also be used. Their melting point is 130 to 170 ° C., preferably 1
40-160 degreeC is good. If it exceeds 170 ° C., the fixing temperature becomes high and the fixing property becomes poor. If the temperature is lower than 130 ° C, it tends to melt during kneading, which is disadvantageous for fine dispersion.

If the amount of microgel is small, there is no effect on hot offset and filming, and if it is large, the fixability deteriorates.
If the molecular weight is low, heat-resistant storage stability becomes a problem, and if it is high, the fixability becomes unacceptable. In addition to the above-mentioned molecular weight characteristics, it is necessary that Tg is 55 to 75 ° C. as a thermal characteristic.

Within this range, basic image characteristics as well as storability are ensured. Further, by finely dispersing the polyolefin to 2 μm or less, the releasing effect can be sufficiently obtained, and the toner can be prevented from being pulverized in the copying machine.
Can be used repeatedly for a long time.

In addition, it was found that the toner using this microgel also has an improved carbon dispersibility. It is considered that the kneading effect is improved because the viscosity necessary for toner dispersion during the toner kneading increases due to the inclusion of the microgel, like the dispersibility of the polyolefin.

Regarding the toner productivity, since the THF insoluble component was not contained, the kneading property was good and the toner productivity was improved by 30 to 70%. The toner is produced by premixing with a mixer such as a V blender or a Henschel mixer and kneading with a two-roll, three-roll, single- or twin-screw kneader.

After cooling, coarse pulverization is carried out with a hammer mill, pulperizer, pin mill feather mill or the like and finely pulverized with jet air. Classifying with Macucut, Alpine, etc. 5
Adjust to a particle size of 30 μm.

[0054]

【Example】

Examples 1 to 3, Comparative Examples 1 and 2 3 equipped with a cooling pipe, a stirrer, a gas introduction pipe and a thermometer
Charge the ion-exchanged water and the monomer to the 1-liter flask. The formulation examples are shown in Table 1 as Examples 1 to 3 and Comparative Examples 1 and 2. The liquid was heated with stirring and the reaction temperature was raised to the specified reaction temperature and the reaction time was 12 hours. The obtained polymer was washed with water and dried at room temperature of 10 torr to obtain a powdery powder having a volatile content of 1% or less.

Resins 300 of Examples 1 to 3 and Comparative Examples 1 and 2
g, carbon black (Sanyo Kasei Co., Ltd. # 40)
20 parts, oil black BY (Orient Chemical) 25
g, polypropylene (660P manufactured by Sanyo Chemical Co., Ltd.) g were melt-kneaded by heating with a two-roll mill. See Table 1 for conditions and results. This was roughly crushed with a hammer mill and finely crushed with a jet air mill. This was classified and adjusted to a particle size of 10 to 11 μm. Next, 50 g of toner and 950 g of EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) were mixed and thoroughly shaken to prepare a developer.

The developer was evaluated in FT8200 manufactured by RICOH, a copying machine. The pulverizability of the toner can be expressed by the processing amount of the pulverizable toner per unit time. In the case of this toner, the air pressure is 5 kg / cm ² .

Compared to Examples 1 to 3, M soluble in THF
When the ratio of w10 ⁷ or more is small, hot offset,
Filming is also poor, and the dispersibility of polypropylene is poor, so the toner spent is also poor. On the other hand, if the amount is large, the hot offset is good but the crushing and fixing properties are poor.

On the other hand, when the melting point of polypropylene is lower than in Examples 4 to 5, the dispersibility of polypropylene is poor and the toner spent is poor. If the melting point of polypropylene is high, the fixability is poor. Therefore, Examples 1 to 5 have good balance of fixability, hot offset, filming, toner spectrum, and pulverizability.

[0059]

[Table 1]

Examples 4 and 5, Comparative Examples 3 to 5 300 g of the resin of Examples 4 and 5 and Comparative Examples 3 to 5, 20 parts of carbon black (Sanyo Kasei Co., Ltd. # 40), Oil Black BY (Orient) 25 g of polypropylene (manufactured by Kagaku Co., Ltd.) and polypropylene (660P manufactured by Sanyo Kasei) were melt-kneaded by heating with two rolls. See Table 2 for conditions and results. This was coarsely pulverized with a hammer mill and finely pulverized with a jet air mill. This was classified and adjusted to a particle size of 10 to 11 μm. Next Tona-50
g and 950 g of EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) were mixed and thoroughly shaken to prepare a developer.

[0061]

[Table 2]

[0062]

The toner of the present invention has an excellent fixing property, an excellent offset resistance, and an excellent filming toner spent even in a high speed system.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a molecular weight distribution of a binder resin used in the toner of the present invention.

Claims (3)

[Claims] 1. A toner comprising a binder resin and a colorant dispersed therein, wherein the binder resin has no THF insoluble matter, contains 5 to 30% of a component having a molecular weight of 1 × 10 ⁷ or more, and has a melting point of 130. A toner for developing an electrostatic charge image, characterized in that a dispersed particle diameter of a polyolefin wax at 170 ° C. is 2 μm or less. 2. The toner for developing an electrostatic charge image according to claim 1, which has a main peak in the range of 2000 to 100,000 in the molecular weight distribution by gel permeation chromatography (GPC) of the THF-dissolved portion of the binder resin. 3. The binder resin has a weight average molecular weight of 20,000 to 20 in a molecular weight distribution of less than 1 × 10 ^7.
The toner for developing an electrostatic charge image according to claim 1, which comprises a vinyl polymer having a number average molecular weight of 1,000 to 10,000 and a Tg of 55 to 75 ° C.