JP3370106B2 - 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 image in electrostatic printing or the like, and is particularly suitable for laser printers and other copying machines having a heat roll fixing mechanism.

[0002]

2. Description of the Related Art In electrophotography, generally, a photoconductive substance is used to form an electric latent image on a photosensitive member by various means, and then the latent image is developed with a toner, and if necessary, the latent image is developed. After the powder image is transferred onto paper or the like, it is fixed by heating or solvent vapor to obtain a copy.

Magnetic brush method, cascade developing method, powder cloud method and the like are known as methods for visualizing an electric latent image by using toner. In any developing method, fixing of the toner image is important. It goes without saying that this is a process.
Especially when considering application to a high-speed copying machine, since a heat roll fixing device is adopted, the toner image and the heat roll come into contact with each other in a heating and melting state at the time of fixing, so that part of the toner image adheres to the heat roll surface. It is required to move, so-called offset does not occur.

To obtain such a toner free from offset, when considering application to a high-speed copying machine which uses a heat roll without using much electric power for a fixing device, that is, a so-called labor-saving high-speed copying machine, Meet difficult problems. That is, in order to prevent offset, the binder polymer used in the toner is required to be as tough as possible and have sufficient melt fluidity. However, in order to have melt flowability, the toner must be heated to a considerably high temperature,
This does not meet the demand for labor saving. Therefore, in order to save labor, fixing at 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 is likely to cause offset.

Conventionally, for the toughening of toner for preventing offset, a high molecular weight polymer having an average molecular weight of about 100,000 or more, particularly a vinyl type polymer is often used. In order to fix a toner using a high molecular weight vinyl polymer at a low temperature, there is a method of lowering the glass transition point of the polymer as low as possible unless blocking is prevented, or lowering the fixing temperature by adding a plasticizer.

However, these methods not only lower the fixing point (minimum temperature at which fixing is completely performed) but also lower the hot offset temperature (temperature at which offset begins to occur) at the same time. This results in only moving the temperature range between the offset temperatures, the so-called fusing latitude, to the low temperature side. Further, if it is attempted to prevent the decrease of the hot offset temperature due to the increase of the weight average molecular weight, the viscosity of the resin is increased, the effect of the glass transition point decrease and the addition of the plasticizer is diminished, and further, the pulverization due to the large amount of cross-linking Accompanied by sexual deterioration.

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 the low temperature fixing toner can be easily obtained.

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

Therefore, in order to take advantage of the properties of the vinyl polymer, which does not cause offset up to a high temperature, and the ability of the polyester to fix even at a low temperature, it is considered to blend both resins. No. 54-114245. However, in the case of a high molecular weight vinyl polymer and a low molecular weight polyester resin, the compatibility between the resins is poor and a non-uniform dispersion state results. In particular, the compatibility becomes worse as the molecular weights of the two differ, and when the dispersed state is observed with a phase contrast microscope, it is observed as if there are islands in the sea. This is also observed when blending poorly compatible plastics, and as a sea-island theory, plastics, 13, No. 9, 1 (19
62).

When the above-mentioned sea-islands are formed in the toner resin, the other components of the toner, such as a polarity controlling agent such as a dye and a coloring agent such as carbon black and a magnetic material, are not sufficiently dispersed. In repeated copying, reversely charged toner or the like is 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 of introducing a common segment into both and forming a graft copolymer has also been proposed. However, in the case of such a copolymer resin, the hot offset resistance and low temperature fixability of the resins are averaged without taking advantage of each other.

[0012]

[Problems to be Solved by the Invention]   To provide a toner suitable for a heat roll fixing method.

To provide a toner having a wide fixing temperature range.

To provide a developer having a balanced hot offset and fixability.

[0015]

The constitution of the present invention for solving the above-mentioned problems is such that the THF-insoluble matter is 5 when the toner is kneaded.
-50% polyester resin or a blend of the polyester resin and a vinyl polymer having a THF-insoluble content of 5-50%, and kneading the binder with other toner components such as pigment and charge control agent. THF of resin by mechanical energy at the time of kneading
Insoluble molecules are cleaved, and their storage modulus (G ') is 5 × 10 ⁵ to 1 × 10 ⁷ dyne / c at 70 to 120 ° C. under the frequency range of 10 to 100 Hz.
A toner having a loss elastic modulus (G ″) of 1 × 10 ³ to 1 × 10 ⁵ dyne / cm ² at m ² of 130 to 180 ° C. and a polyester resin used for the toner has an acid value of 1 to 5 mgKOH. / G and hydroxyl value of 30-80 mgK
It is necessary to have characteristics of OH / g and glass transition point of 55 to 70 ° C.

(A) Description of Rheological Properties The fixability of the heat roller fixing toner is closely related to the melt viscoelasticity of the toner. Conventionally, the melt viscoelasticity of heat roller fixing toner has been measured by a flow tester, melt index, etc., but only the apparent viscosity of the melt is measured by these. However, the resin melt is a material that exhibits both typical viscosity and elasticity, and it is necessary to quantitatively analyze this viscoelastic property.

In the rheological properties of the toner composition,
The storage modulus (G ′) relates to the cohesive force of this composition, while the loss modulus (G ″) relates to the viscosity of the composition. The larger G ′, the greater the cohesive force and the offset. Although it decreases, the fixability deteriorates, and when G ″ increases, the fixability improves but the offset increases. On the other hand, the temperature at the time of fixing the toner is currently substituted by the surface temperature of the fixing roller, but it is actually known that the toner is fixed at a lower toner temperature.

Therefore, the present inventor has found the following new facts as a result of research on the correlation between the viscoelastic property at the fixing temperature and the fixability and hot offset of the heat roller fixing toner using polyester as the binder resin.

In order to cover the actual fixing temperature range, the storage elastic modulus (G ′) is 5 × 10 ⁵ to 1 × 10 ⁷ dyn at 70 to 120 ° C. under the frequency of 10 to 100 Hz.
It is preferably in the range of e / cm ² . In order to improve the hot offset, the loss elastic modulus (G ″) at the boundary temperature between the toner and the roller surface, that is, 130 to 180 ° C., is 1 × 10 ³ to 1 × 10 ⁵ dyne / cm ^2. Good.

To obtain the rheological properties of the above toner, the glass transition point is 55 to 70 ° C. and the THF insoluble content is 5 to
50% polyester resin is kneaded with other toner components.

The ratio obtained not only by using the polyester resin alone but also by blending the polyester resin and the vinyl-based polymer is preferably in the range of polyester resin / vinyl-based polymer 1 / 0.1 to 0.4. The hot offset environment resistance, which is a drawback of the resin, can be improved.

Regarding the rheological properties of this toner, the polyester resin has a glass transition point of 55 to 70 ° C., a THF insoluble content of 5 to 50%, an acid value of 1 to 5 mgKOH / g, and a hydroxyl value of 30 to 80 mgKOH / g. It is necessary that the vinyl polymer has a glass transition temperature of 55 to 70 ° C. and a THF insoluble content of 5 to 50%, and the polyester alone is a blend of polyester and vinyl resin and kneaded with other toner components. Is obtained by

The rheological properties of the above-mentioned toner are highly dependent on the branched polymer of the THF-soluble portion of the polyester or vinyl polymer cleaved by mechanical energy.

The method for measuring rheological properties will be described below.

The toner is hot-pressed to 20 mm × 20 m
A sample is prepared by molding into a sheet having an m-square direction and a thickness of 2 mm. Using a DVE type Rheospectler manufactured by Rheology Co., Ltd. as a measuring device, maintaining the sample at a predetermined temperature and applying sinusoidal vibration (measurement frequency 10 to 100 Hz) in the shearing direction by a forced vibration non-resonance method, The stress response under ultra-small displacement is measured, and the storage elastic modulus (G ′) loss elastic modulus (G ″) and tangent loss (tan δ) are obtained from the power and dynamic strain by a known calculation method.

(B) Method for Obtaining Crosslinked Polyester The polyester resin used as a binder in the present invention is obtained by polycondensation of an alcohol component and a carboxylic acid component.
For example, diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol and 1,4-butenediol, 1,4- Examples thereof include bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, and other dihydric alcohol monomers.

Examples of the carboxylic acid component include 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, acid anhydrides or lower alkyl esters thereof, dimers of linoleic acid, and other divalent organic acid monomers.

The polyester resin used in the present invention is not limited to the above difunctional monomers, but is also a trivalent or higher polyvalent carboxylic acid monomer as a carboxylic acid component of a trifunctional or higher polyfunctional monomer. It is a polymer containing the acid anhydride. Examples of the trivalent or higher polyvalent carboxylic acid monomer as the polyfunctional monomer include, for example, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4- Cyclohexanetricarboxylic acid, 2,
5,7-naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, 1,2,4-butane tricarboxylic acid, 1,2,5-hexane tricarboxylic acid, 1,3-
Dicarboxyl-2-methyl-2-methylenecarboxylic propane, tetra (methylenecarboxylic) methane,
1,2,7,8-octane tetracarboxylic acid, embol trimer acid and these acid anhydrides, etc. can be mentioned.

It is necessary that the content of the carboxylic acid component of the polyfunctional monomer having three or more functional groups is 10 to 60 mol%.

The trihydric or higher polyhydric alcohol used in the present invention may be any polyhydric alcohol generally known as a trihydric or higher polyhydric alcohol. For example, glycerin, 1,1,1-trimethylolethane,
1,1,1-trimethylolpropane, 1,1,1-trimethylolbutane, pentaerythritol, 1,1,
2,2-tetramethylolethane, 1,1,3,3-tetramethylolpropane, sorbitol, polyvinyl alcohol and the like can be mentioned. These are used in one kind or a mixed system of two or more kinds.

Of the above polyhydric alcohols having 3 or more valences,
Glycerin, 1,1,1-trimethylolpropane and pentaerythritol are preferred from the viewpoint of esterification reactivity and cost. The amount of these used is 1 to 40 with respect to all acid components.
The range of mol% is preferable, and 2 to 25 mol% is more preferable.

The production method for obtaining the polyester of the present invention is not particularly limited, and the esterification reaction can be carried out by a known method. The transesterification reaction can be carried out by a known method, and at this time, a known transesterification catalyst can be used. For example, magnesium acetate, zinc acetate, manganese acetate, calcium acetate, tin acetate, lead acetate, titanium tetrabutoxide and the like can be mentioned.

The polycondensation reaction can be carried out by a known method, in which case a known polymerization catalyst can be used. Specific examples include antimony trioxide, germanium dioxide and the like.

B ') About 1.0 g of a resin shown in the following method for measuring THF insoluble matter 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.

C) Synthesis of vinyl resin In the vinyl polymer of the present invention, a vinyl copolymer in which styrene is polymerized in an amount of 50 to 100% by weight, preferably 60 to 90% by weight is used as a component. preferable. 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, methoxydiethylene glycol methacrylate, butoxytriethylene glycol methacrylate, methoxydipropylene glycol methacrylate, methacryl Phenoxyethyl acid, phenoxydiethylene glycol methacrylate Phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyl oxyethyl methacrylate, N-vinyl-2-pyrrolidone methacrylate, methacrylonitrile, methacryloyl Amide, N-methylol methacrylamide, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, 2-hydroxy-3-phenyloxypropyl methacrylate, diacetone acrylamide, acrylic acid, methyl acrylate, acrylic Ethyl acid, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate,
Heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate, acrylic Acid ethoxydiethylene glycol,
Methoxyethylene glycol acrylate, butoxyethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, benzyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, Dicyclopentenyl acrylate, Dicyclopentenyl oxyethyl acrylate, N-acrylate
Vinyl-2-pyrrolidone, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, glycidyl acrylate, acrylonitrile, acrylamide, N-methylol acrylamide, diacetone acrylamide, 1 such as vinyl pyridine
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, Dorokishipiparin acid neopentyl glycol diacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate,
Tris (methacryloyloxyethyl) isocyanurate, half-esterified product of glycidyl methacrylate and methacrylic acid or acrylic acid, bisphenol type epoxy oil and fat and methacrylic acid or acrylic acid half-esterified product, glycidyl acrylate and methacrylic acid or half-acrylic acid A vinyl monomer having two or more vinyl groups in one molecule such as an esterified product is used.

Of these, preferred vinyl-based monomers are vinyl-based monomers having one vinyl group in one molecule, such as styrene, styrene derivatives, methacrylic acid esters, and acrylic acid esters. Particularly preferred are styrene and alkyl esters of methacrylic acid or acrylic acid having 1 to 5 carbon atoms in the alkyl group.
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.

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-butyl peroxyketal, 2-octanone di-tert-butyl peroxyketal, acetone di-tert-butyl peroxyketal, peroxide radical initiators such as diisopropylbenzene hydroperoxide, 2,2′-azobisisobutyrate Ronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, 1, There are azobis-based radical initiators such as 1′-azobis (cyclohexane-1-carbonitrile). These are preferably 0.01 to 20% by weight, particularly preferably 0.1 to 20% by weight, based on the total amount of the monomers.
-10% by weight is used.

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

When aqueous suspension polymerization is carried out, 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, hydroxyapatite, 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.

(D) Method for Producing Toner and Developer The toner binder resin obtained as described above is appropriately melt-mixed with a colorant and / or magnetic powder and, if necessary, a charge control agent and other additives. To obtain an electrostatic image developing toner.

As the colorant, carbon black, iron oxide pigment, phthalocyanine blue, phthalocyanine green, rhodamine 6G lake, watching red strontium, etc., which are conventionally known, can be used, and the range is 1 to 60% by weight in the toner. Select as appropriate for use.

As the charge control agent, a nigrosine dye, a fatty acid-modified nigrosine dye, a metal-containing nigrosine dye, a metal-containing fatty acid-modified nigrosine dye, a chromium complex of 3,5-tert-butylsalicylic acid, or the like can be used. Used in 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, and these are usually used. Used in toner in an amount of 0 to 10% by weight.

(E) Method for obtaining rheological properties in a specific range Next, molecules of the THF-insoluble domain of polyester are cut by mechanical energy, and storage elastic modulus (G) at 70 to 120 ° C. at a frequency of 10 to 100 Hz. ') Is 5 × 10
⁵ to 1 × 10 ⁷ dyne / cm ² , loss elastic modulus (G ″) at 130 to 180 ° C. is 1 × 10 ³ to 1 × 10 ⁵ dyn
A method for obtaining a toner having a rheological property defined by e / cm ² will be shown. The crosslinked polyester resin having a THF insoluble content of 5 to 50% obtained by the method (B) alone or 10 to 40% of a THF insoluble content of 5 to 50% crosslinked vinyl polymer is mixed with carbon black, a charge control agent or other additives. And knead. At this time, the THF insoluble matter is 5 in the whole resin.
% Or less, storage elastic modulus (G ′) at 70 to 120 ° C.
Is less than 1 × 10 ⁵ dyne / cm ² and TH
Storage elastic modulus (G ') of 1 x 1 when F insoluble content is 50% or more
It becomes more than 0 ⁷ dyne / cm ² .

In the case of kneading, first, the mixture is pre-kneaded with a kneading machine such as a V blender or a Henschel mixer, and then a hot roll,
It is kneaded by a pressure kneader, a Banbury mixer, a single-screw or twin-screw 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 ³ to 10 ⁷ poise. When kneaded at a viscosity lower than this viscosity range, the molecules are hard to be cut, and the crosslinked component remains in the toner. As a result, G'becomes large and the fixability deteriorates. When kneaded with a high viscosity, it does not disperse with other materials. In the case of kneading in the above viscosity range, the rheological property can be known depending on the amount of the crosslinked component and the kneading conditions. In other words, this method has the characteristic that any rheological property in this range can be produced, and this cannot be obtained with a chain polyester. The relationship between the viscosity and the toner quality is shown in Graph 1 and Graph 2.

The polyester used in this method has a Tg of 55.
Those at ˜70 ° C. are preferred. When the temperature is 55 ° C or lower, the fixability is improved, but the storage stability and hot offset are deteriorated,
In the above case, G ′ at 70 to 120 ° C. is 10 ⁷ dyn
e / cm ² or more, and the fixability deteriorates.

(F) Polyester resin and vinyl-based polymer blend The polyester resin contains carboxyl groups and hydroxyl groups as functional groups in the polymer because of its structure, so that the charging stability against environmental changes is higher than that of vinyl-based polymers. Will get worse.
Therefore, when a vinyl-based polymer is blended and used for the purpose of compensating for the drawbacks of the polyester resin, good results are obtained. When the vinyl-based polymer is polyester / vinyl ester 1 / 0.4 or more, the wettability to the paper becomes poor, and the viscosity becomes high due to the high molecular weight, so that the low temperature fixing property becomes poor. Furthermore, the PVC matting property becomes worse 1/0.
If it is 1 or less, there is no effect.

Further, the acid value and hydroxyl group (OH group value) of the polyester resin are 1 to 5 mgKOH / g and 30 to 80, respectively.
The optimum is mgKOH / g.

In the case of polyester resin, the hydroxyl value is 30 mgKOH / g or less and the acid value is 1 mgKOH because of the reaction characteristics.
/ G or less is difficult.

When the hydroxyl value and the acid value are 80 mgKOH / g or more and 10 mg / g or more, respectively, there is a tendency for deterioration due to environmental changes.

In the sea-island structure, which is caused by the poor compatibility between the resins generated by blending the polyester and the vinyl polymer, no resin having a rheological property in this range is generated and the dispersibility is good. It is considered that this is because not only the rheological properties are effective, but also the change in the physical properties of the resin due to the branched structure.

(F) Relationship between Fixability and Viscoelastic Property A patent that defines the toner dynamic viscoelasticity when a polyester resin is used to improve heat roll fixing is disclosed in Japanese Patent Laid-Open No. 2-15.
8747, JP-A-63-296065, JP-A-1-20
No. 4066 and Japanese Patent Application Laid-Open No. 3-2765, but in the toner produced according to these, the desired shearing force of the polymer in the toner and the cross-linking component of the resin are poorly balanced, and the desired branched polymer cannot be obtained.

In particular, as a characteristic of this branched polymer, for example, the toner has a transition region in the temperature dependence of the elastic modulus of the toner described in the article by Tsunego Fujie and Shoichi Nakano. After that, it is said that the fixing of the toner occurs from the rubber-like plateau region to the rubber-like flow region, though it is changed to the rubber-like plateau region and the rubber-like flow region.

When it completely enters the rubbery flow region, the hot offset becomes worse. In other words, as the desired viscoelastic properties of the toner, the wider the rubbery plateau region is, the more advantageous it is with respect to the fixing temperature region. The fixing and viscoelastic properties of the toner obtained this time are in good agreement with the content of this dedication, and the toner containing the branched polymer has a wide rubbery plateau region, so good fixing properties can be obtained while hot offset Will also be advantageous.

The toner of the present invention can be used in 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 a ferromagnetic element but exhibiting ferromagnetism by appropriate 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 70 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 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 development method, the magnetic brush development method, the O-shell development 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, C
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 can be 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.

Synthesis Example A-1 Synthesis of Polyester Resin Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 400 g Polyoxyethylene (2) -2,2-bis (4-hydroxy) Phenyl) propane 350 g Ethylene glycol 200 g Terephthalic acid 600 g Benzenetricarboxylic acid 180 g Dibutyltin oxide 2.5 g is put in a glass 3 liter 4-neck flask, a thermometer, a stainless stir bar, a downflow condenser and a nitrogen inlet pipe are attached to the mantle. 6 at 190 ° C under a nitrogen stream in a heater
As a result of reaction over time, the viscosity increases and the stirring torque is 3.5 kg · cm.
When the temperature reached, the reaction temperature was lowered and the reaction was terminated.

Polyester resins were obtained by charging Synthesis Examples A-2 and A-3 according to the following formulation.

[0064]

[Table 1]

Comparative Synthetic Examples Comparative synthetic examples using a polyester resin having a THF insoluble content of 0% and 60% as compared with the above synthetic examples are shown in B-1 and B-2, and the temperature at the time of kneading is increased to B-3. A comparative synthesis example when the melt viscosity is low is shown.

[0066]

[Table 2]

[0067]

EXAMPLES The present invention will be specifically described below with reference to examples.

Examples 1 to 3 and Comparative Examples 1 to 3 Polyester Resins Obtained in A-1 to 300 g Carbon Black (Mitsubishi Kasei # 40) 20 g Oil Black BY (Orient Chemical) 25 g with two rolls It was melted and kneaded by heating. The kneading conditions are shown in Table 3, and the molecular cutting of the resin occurs due to this kneading.

The obtained kneaded product was roughly pulverized with a hammer mill and finely pulverized with a jet air mill. This was classified, and the particle size was adjusted to 10 to 11 μm to obtain a toner. Next, 50 g of each of these toners was mixed with 950 g of EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) and thoroughly shaken to prepare a developer. This is Examples 1-3.

Comparative Examples 1 to 3 are the same as Examples 1 to 3 except that the polyester resins of the above Examples were replaced with those of Synthetic Comparative Examples B-1 to 3.

Using these developers, the evaluation was carried out using a copying machine (FT7050 manufactured by Ricoh). The results are shown in Table 3 below.

Toner evaluation result

[0073]

[Table 3]

The rheological properties of Example 1 are shown in FIGS. 1 and 2.

1. Examples 1 to 3 show good results with respect to the contradictory qualities of both hot offsets as compared with Comparative Examples 1 to 3.

2. In Comparative Example 1, when the insoluble matter does not exist, the fixability is excellent, but the hot offset and carbon dispersibility are poor.

3. In Comparative Example 2, when the amount of insolubles is large, the rheological properties after kneading are high.

In this case, the hot offset is sufficiently satisfied, but the fixability is poor.

4. In Comparative Example 3, the melt viscosity was lowered because the kneading temperature was increased. Because of this, the shear is weak and insoluble matter remains. If this insoluble matter remains, the fixability deteriorates.

Examples 4 to 7 and Comparative Examples 4 and 5 Examples and Comparative Examples of Polyester Resin and Vinyl Resin Mixture Production Process of Vinyl Polymer Flask with a capacity of 3 liters equipped with a cooling pipe, a stirrer, a gas introduction pipe and a thermometer. Charge ion-exchanged water and monomer into. The formulation examples are shown in Table 4 for Examples 6-8. 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.

[0081]

[Table 4]

Toners 4 to 7 of a mixture of polyester resin and vinyl resin Comparative toners 4 and 5.

The mixture is made into a toner with a mixture of the polyester resins of Synthesis Examples A-1 to 3 and the vinyl resins of Synthesis Examples A-4 to 6.

The toner conditions are the same as those described above.

Comparative Example Toner 4 Combination of resin and vinyl resin having high insoluble content of polyester resin Toner 5 Ratio of polyester resin to vinyl resin is 50
Comparative example when toner is formed at / 50 These results are shown in Table 5.

[0086]

[Table 5]

Results-Example toners 4 to 7 are superior to Comparative toners 4 and 5 in the lower fixing limit and vinyl chloride matting property.

Comparative Example 4 is a polyester resin THF.
Since the insoluble content is high, the toner contains the insoluble content. Therefore, since the rheological property is high, the lower limit of fixing is increased. -In Comparative Example 5, since vinyl resin is contained in an amount of 30% or more, the vinyl chloride matte property deteriorates.

[0089]

The effects of the present invention described above are summarized as follows.

(1) The Invention of Claim 1 By applying mechanical shearing energy to a polyester resin having a THF-insoluble content, the network structure can be molecularly cut to obtain the viscoelastic properties required for the toner.

(2) Invention of Claim 2 The toner having the viscoelastic characteristics described in Claim 2 becomes a toner having a good balance of fixing property and hot offset. (3) Invention of Claim 3 and Claim 3 By using a polyester resin having a range, a toner having excellent fixing properties can be obtained.

(4) Invention of Claim 4 By blending the polyester resin of Claims 1 and 2 with a vinyl resin, the charging stability is improved against environmental changes.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between G ′ and temperature in Example 1.

FIG. 2 is a graph showing the relationship between G ″ and temperature in Example 1.

Continuation of front page (56) Reference JP-A-3-41471 (JP, A) JP-A-4-174866 (JP, A) JP-A-1-105957 (JP, A) JP-A-3-188468 (JP , A) JP-A-1-307767 (JP, A) JP-A-2-989 (JP, A) JP-A-2-173038 (JP, A) JP-A-4-83262 (JP, A) JP-A 4-83263 (JP, A) JP 3-64766 (JP, A) JP 2-167563 (JP, A) JP 58-14147 (JP, A) JP 63-127254 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 9/087

Claims (2)

(57) [Claims] 1. A polyester resin having a THF insoluble content of 5 to 50% alone, or this polyester resin and THF.
A toner composition containing a mixture of a vinyl resin having an insoluble content of 5 to 50% as a resin component is kneaded, and the mechanical energy at the time of kneading cuts the molecule of the resin component to thereby dissolve THF. And the rheological properties of the toner composition after kneading have a frequency of 10 to 10
The storage elastic modulus (G ′) is 5 × 10 ⁵ to 1 × 10 ⁷ dyne / cm ² , and 70 to 120 ° C. under 0 Hz.
Loss elastic modulus (G ″) is 1 × 10 at 30 to 180 ° C.
An electrostatic charge image developing toner having a density of ³ to 1 × 10 ⁵ dyne / cm ² . 2. The glass transition point of the polyester resin is 55.
~ 70 ° C, acid value 1 ~ 5mgKOH / g, hydroxyl value 3
The electrostatic charge image developing toner according to claim 1, having a characteristic of 0 to 80 mgKOH / g.