JPH0727280B2 - Electrostatic image developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention develops an electrostatic latent image formed on the surface of a latent image carrier in, for example, electrophotography, electrostatic printing, electrostatic recording, or the like. The present invention relates to an electrostatic image developer used for

[Background of technology]

For example, in electrophotography, an electrostatic latent image is usually formed on a latent electrostatic image bearing member made of a photoconductive photoconductor by charging and exposure, and then this electrostatic latent image is formed by toner, which is a colored particle. After development, the obtained toner image is transferred to a transfer material such as paper and then fixed by heat or pressure to form a visible image.

As a method for fixing a toner image, conventionally, a method of heating and melting the toner in a non-contact state with a heater to fix the toner,
Known methods include a method in which toner is dissolved and fixed by an organic solvent, a method in which toner is pressed and fixed, and a heating roller fixing method in which a heating roller is brought into direct contact with the toner to melt and pressure-fix the toner to fix the toner. The heating roller fixing method is widely used because of its high thermal efficiency and high-speed fixing.

However, recently, (a) suppressing deterioration of the copying machine due to overheating, and (b) shortening the warm-up time required to raise the temperature of the heating roller to a fixing possible temperature after operating the heating roller fixing device. (C) To reduce the temperature drop of the heating roller due to the absorption of heat by the transfer material such as paper to enable stable image formation a number of times in succession. From the viewpoints of downsizing and improvement of safety, there is a strong demand for reducing the power consumption of the heater incorporated in the fixing device to enable the fixing process with the temperature of the heating roller being lowered.

Therefore, the toner is required to (1) be able to achieve good fixing at a lower temperature, that is, to have an excellent low-temperature fixing property, and basically, the following conditions are required. is necessary.

(2) In the heating roller fixing method which is preferable as the fixing method, the offset phenomenon, that is, a part of the toner forming the image at the time of fixing is transferred to the surface of the heating roller and retransferred to the transfer material sent next. Since the phenomenon of smearing the image is likely to occur, it is necessary to impart the toner with a property that does not easily transfer to the heating roller, that is, offset resistance.

(3) It can exist stably as a powder without aggregation under the conditions of use or storage environment, that is, it has excellent blocking resistance.

(4) It has good triboelectrification properties, and the development process, transfer process, and cleaning process are performed well, and a clear image free from fog is obtained.

(5) The occurrence of a so-called filming phenomenon in which a toner substance adheres to the surface of a latent image carrier or the surface of carrier particles is suppressed, and an image can be stably formed many times.

Therefore, conventionally, in order to improve the offset resistance, a technique has been proposed in which a resin composed of a low molecular weight polymer component and a high molecular weight polymer component is used as a binder resin for toner particles (special feature: JP-A-56-158340,
(See JP-A-56-16144 and JP-A-58-202455).

[Problems to be solved by the invention]

However, in the above technique, since the high-molecular weight polymer component is present in the toner particles, the offset generation temperature increases and the offset resistance can be improved, but at the same time, the fixable temperature also increases. Therefore, it becomes difficult to improve the low temperature fixability.

On the other hand, when a binder resin having a low glass transition point or a low softening point is used only in consideration of the improvement of low-temperature fixability of the toner, not only the offset resistance is lowered but also the blocking resistance is lowered, and the developer is There is a problem that the filming phenomenon in which the toner substance is attached to the carrier or the carrier to form a film is apt to occur, and the durability of the developer is lowered.

On the other hand, in order to satisfy low temperature fixing property, offset resistance, blocking resistance, and filming resistance,
As a binder resin, a technique using a resin obtained by reacting a polymer having a carboxy group with a metal compound has been proposed (for example, JP-A-57-178250 and JP-A-61-1101).
55, JP-A-61-110156, etc.).

However, in such a technology, especially under high temperature and high humidity environment conditions (for example, a temperature of 33 ° C. or higher and a relative humidity of 80% or higher), triboelectrification becomes poor and fog is liable to occur, and carrier particles and a latent image bearing member are easily generated. There is a problem that the filming phenomenon due to the toner substance is likely to occur, and the residual toner is easily fused to the cleaning blade to cause cleaning failure.

Also, especially under low temperature and low humidity environment conditions (for example, a temperature of 10 ° C or less,
At a relative humidity of 40% or less), the temperature of the transfer material such as paper is low, so the toner is likely to be insufficiently melted during fixing, and as a result, poorly fixed toner adheres to the rollers that make up the fixing device and accumulates. As a result, the roller is contaminated, which causes a conveyance failure such as a paper jam, and shortens the service life of the roller.

The present invention has been made based on the above circumstances, and has low-temperature fixability, offset resistance, blocking resistance,
It is intended to provide an electrostatic image developer which has excellent filming resistance and cleaning properties and can stably form a clear image free from fog many times regardless of environmental conditions.

[Means for solving problems]

The electrostatic image developer of the present invention comprises toner particles (a) containing an ionically crosslinked vinyl copolymer as a binder resin, and 0.01 to 3 parts by weight per 100 parts by weight of the toner particles (a). Part of organic fine particles (b), wherein the binder resin has a molecular weight distribution of at least two groups of a low molecular weight component and a high molecular weight component, and In the above, the maximum value of the low molecular weight component is in the range of 1 × 10 ³ to 2 × 10 ⁴ , and the maximum value of the high molecular weight component is in the range of 1 × 10 ⁵ to 2 × 10 ⁶ , The resin is composed of (a) a styrene-based monomer, (b) an acrylic acid ester-based monomer or a methacrylic acid ester-based monomer, and (c) a carboxy group-containing monomer represented by the following general formula (A). Crosslinked polymer obtained by reacting the obtained polymer with a polyvalent metal compound There, the organic fine particles (B) is spherical, the average diameter of the primary particles
It is characterized by comprising a vinyl polymer having a thickness of 0.01 to 5 μm.

General formula (A) (In the formula, R ¹ represents a hydrogen atom or an ethyl group, L represents a divalent bonding group having 3 or more carbon atoms and having an ester bond in the molecular chain, and may have a substituent.) Effect of the Invention] According to the developer of the present invention, since the toner particles contain the ionically crosslinked vinyl copolymer as a binder resin, a strong crosslinkage is formed under non-heating. In this state, excellent blocking resistance, filming resistance, and cleaning performance are exhibited, and generation of fine powder that causes contamination due to collision with the triboelectrification member is suppressed. And durability is demonstrated. The ionic cross-linking bond has a smaller bonding force than the covalent bond and is easily broken by heating. Therefore, a considerable part of the cross-linking bond is cut off during heat fixing, which results in a conventional bond having a similar glass transition point. Viscosity at the time of melting is lower than that of a toner containing an adhesive resin, so that the penetration of the melted toner between fibers of a transfer material such as paper is made good,
As a result, fixing can be achieved at a lower temperature than before and with a sufficient fixing force. Therefore, it is possible to prevent the roller or the transfer material from being contaminated due to defective fixing, and it is possible to remarkably improve the life of the fixing device.

Moreover, in the present invention, since the organic fine particles are mixed with the toner particles, the organic fine particles are present in a state in which the organic fine particles are weakly attached to the surface of the toner particles. The probability that the particles directly contact the latent image bearing member and damages the latent image bearing member is significantly reduced, and as a result, a stable image can be formed many times without defective cleaning. Further, by selecting a relatively hard material as the constituent material of the organic fine particles, suitable polishing performance by the organic fine particles is exerted so that the toner substance adhering to the surface of the latent image carrier or the carrier particles is removed. Therefore, the occurrence of the filming phenomenon can be suppressed.

[Specific configuration of the invention]

In the present invention, toner particles containing a cross-linked polymer obtained by reacting a specific vinyl polymer and a polyvalent metal compound as a binder resin, and specific organic fine particles in a specific ratio as an essential component It is used to form an electrostatic image developer.
The electrostatic image developer of the present invention may be either a one-component developer containing no carrier particles or a two-component developer containing carrier particles.

The organic fine particles have a spherical shape in order to improve durability, and the primary particles have an average diameter of 0.01 to 5 μm, particularly 0.03 to 3
μm is preferred. If this average diameter is too small, the spacer effect due to the organic fine particles is small and cleaning failure is likely to occur. On the other hand, when it is too large, the triboelectric chargeability of the toner is likely to be impaired.

The ratio of organic fine particles is 100 parts by weight of toner particles.
It is 0.01 to 3 parts by weight, particularly preferably 0.1 to 2 parts by weight. When the ratio of the organic fine particles is too small, the spacer effect is small and cleaning failure is likely to occur. On the other hand, when it is too large, the triboelectric charging property of the binder resin particles is likely to be impaired.

The organic substance for forming the organic fine particles is a vinyl polymer because it is excellent in moisture resistance and stabilization of triboelectrification. Such vinyl polymer is produced by various polymerization methods such as emulsion polymerization method and suspension polymerization method,
The emulsion polymerization method is preferred because spherical organic particles having a small diameter can be efficiently obtained. In particular, it is preferable to obtain the vinyl polymer by an emulsion polymerization method without using an emulsifier in a system where the monomer itself for obtaining the vinyl polymer has an emulsifying action. On the other hand, when an emulsifier is used, the triboelectric chargeability of the toner may be hindered by the emulsifier, or the humidity dependence of the triboelectric chargeability may increase.

As the vinyl polymer, an acrylic polymer is particularly preferable. This acrylic polymer is a homopolymer or copolymer obtained by polymerizing a monomer selected from acrylic acid or acrylic acid ester, methacrylic acid or methacrylic acid ester. Acrylic monomers used to obtain such an acrylic polymer include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate. , Dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-chloromethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate , N-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethyl methacrylate. Minoechiru, mention may be made of diethylaminoethyl methacrylate and the like.

Among the acrylic polymers, polymethylmethacrylate is most preferable. With polymethyl methacrylate, it is possible to easily obtain uniform and small-sized organic fine particles,
Contamination of the latent image carrier, the wall of the developing device, the carrier for the developer and the like is unlikely to occur, and there is no fear of impairing the triboelectric charging property of the toner, so that stable developing performance can be obtained.

The acrylic polymer may be a copolymer of other monomers, if necessary. In this case, it is preferable to use the acrylic monomer in the monomer composition in a proportion of 50% by weight or more. Examples of such other monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene and p.
-Ethylstyrene, 2,4-dimethylstyrene, pn-
Butyl styrene, p-tert-butyl styrene, pn-
Hexyl styrene, pn-octyl styrene, pn
-Nonylstyrene, pn-decylstyrene, pn-
Styrene-based monomers such as dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; acetic acid Vinyl esters such as vinyl, vinyl acetate, vinyl benzoate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone; dienes such as butadiene and isoprene; maleic acid, fumaric acid, etc. Saturated carboxylic acids; others can be mentioned.

The organic fine particles are preferably used by being externally added to and mixed with the toner particles. Specifically, it is preferable that the organic fine particles are present on the surface of the toner particles by mixing the toner particles and the organic fine particles using a mixing device such as a V-type blender.

The toner particles contain an ionically crosslinked vinyl-based copolymer (hereinafter also referred to as “specific vinyl-based copolymer”) as a binder resin, and if necessary, a colorant in the binder resin,
A charge control agent, a fixability improver, magnetic particles and the like are contained. In particular, the ionically crosslinked vinyl copolymer is a vinyl copolymer having a carboxy group in which the polyvalent metal compound reacts with the carboxy group to form an ionically crosslinked bond.

The glass transition point Tg of the specific vinyl copolymer is 40 to
70 ° C is preferable, and 40 to 60 ° C is particularly preferable. By selecting one having a glass transition point Tg in such a range, more excellent low-temperature fixability, offset resistance and durability can be obtained. That is, when the glass transition point Tg is too small, the toner particles may become soft and the offset resistance and durability may be lowered, while on the other hand, when the glass transition point Tg is too high, the low temperature fixing property tends to be lowered. In some cases, sufficient low-temperature fixability may not be obtained especially under low temperature and low humidity (for example, temperature 10 ° C., relative humidity 40%) environmental conditions. In the present invention, the glass transition point Tg is a differential scanning calorimeter “low temperature DSC” (manufactured by Rigaku Denki Co., Ltd.), when measured at a temperature rising rate of 10 ° C./min. Is the temperature at the intersection of the extension line and the tangent line showing the maximum slope from the rising portion of the peak to the peak apex.

The specific vinyl-based copolymer has a molecular weight distribution that is divided into at least two groups, a low molecular weight component and a high molecular weight component, and gel permeation chromatography (GP
In the molecular weight distribution curve measured by C), the maximum value on the low molecular weight component side is in the range of 1 × 10 ³ to 2 × 10 ⁴ ,
It has at least two local maximum values in the range of 1 × 10 ⁵ to 2 × 10 ⁶ on the high molecular weight component side. By selecting one having such a molecular weight distribution, it becomes possible to further improve low-temperature fixability and offset resistance. In addition, since it is possible to make the specific vinyl-based copolymer tough by the high-molecular weight component, the toner particles are less likely to be destroyed in the friction with the carrier or the collision with the latent image carrier, As a result, generation of fine powder can be suppressed, and contamination of the surface of the latent image carrier can be effectively prevented. Therefore, it is possible to stably form a clear image without fog a number of times.

On the other hand, in the above-mentioned molecular weight distribution curve, when the maximum value of the low molecular weight component is too small, the blocking resistance of the toner may decrease, while when the maximum value is excessive, the low temperature fixing property of the toner decreases. There is a case. Further, when the maximum value of the high molecular weight component is too small, the offset resistance and durability of the toner may decrease, while when the maximum value is too large, the low temperature fixability of the toner may decrease.

Further, the proportion of the high molecular weight component is preferably 15% by weight or more of the vinyl polymer having a carboxy group, and particularly preferably 15 to 50% by weight. If the proportion of the high molecular weight component is too small, the offset resistance and durability of the toner may be reduced.

When introducing a carboxy group into a vinyl polymer containing such a high molecular weight component and a low molecular weight component, it is sufficient that at least the low molecular weight component has a carboxy group introduced. That is, the destruction of the toner particles caused by friction with the carrier particles or collision with the surface of the latent image bearing member is mainly due to the low molecular weight and relatively fragile components in the toner particles. By using a polyvalent metal compound to be described later to crosslink by an ionic bond, so to speak, to make it tough, it is possible to effectively suppress the generation of fine powder caused by the destruction of toner particles, which is a factor of the filming phenomenon.

The specific vinyl copolymer preferably has a ratio Mw / Mn of weight average molecular weight Mw to number average molecular weight Mn of 3.5 or more, and more preferably 4 to 40.
By selecting one having a ratio Mw / Mn value of 3.5 or more, further 4 to 40, the offset resistance and mechanical durability of the toner are further improved.

The values of the weight average molecular weight Mw and the number average molecular weight Mn are
It can be determined by various methods, and although there is some difference depending on the difference in the measuring method, in the present invention, it is determined by the following measuring method.

That is, the weight average molecular weight M is determined by gel permeation chromatography (GPC) under the following conditions.
w, number average molecular weight Mn, peak molecular weight are measured. Temperature 40
1.2 ml / min of solvent (tetrahydrofuran) at ℃
Flow at a flow rate of, and inject 3 mg of a tetrahydrofuran sample solution with a concentration of 0.2 g / 20 ml as a sample weight for measurement. When measuring the molecular weight of a sample, select the measurement conditions that fall within the range in which the logarithm of the molecular weight of the calibration curve and the count number are linear, using monodisperse polystyrene standard samples of which the sample has several molecular weights. .

The reliability of the measurement results was measured under the above measurement conditions.
NBS706 polystyrene standard sample (weight average molecular weight Mw = 28.8
× 10 ⁴ , number average molecular weight Mn = 13.7 × 10 ⁴ , Mw / Mn = 2.11) ratio M
Check that the w / Mn value is 2.11 ± 0.10.

Any GPC column may be used as long as it satisfies the above conditions.
Specifically, for example, TSK-GEL, GMH (manufactured by Toyo Soda Co., Ltd.) and the like can be used.

The vinyl-based copolymer for obtaining the specific vinyl-based copolymer includes (a) a styrene-based monomer, (b) an acrylic acid ester-based monomer or a methacrylic acid ester-based monomer, and (c) ) A polymer obtained by using three of the monomers containing a specific carboxy group as essential components.

Usually, in order to obtain a vinyl-based monomer having a carboxy group, a copolymer selected from the above-mentioned monomers and a monomer selected from acrylic acid or methacrylic acid and derivatives thereof as an essential component is used. Good.

Examples of the monomer having a carboxy group for such copolymerization include a hydroxyl group-containing half-ester compound having a structure obtained by an esterification reaction between an acrylic acid ester or a methacrylic acid ester or a derivative thereof and a dicarboxylic acid compound. Can be mentioned.

According to such a half-ester compound, since the carboxy group is introduced at a position that has little influence on the main chain constitution, the steric hindrance of the chemical structure is reduced, and as a result, the reaction between the carboxy group and the polyvalent metal compound is reduced. It is possible to efficiently proceed to form an ionic bond and obtain the specific vinyl-based copolymer having a good cross-linked structure.

Examples of the styrene-based monomer for obtaining the vinyl-based copolymer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene,
p-ethylstyrene, 2,3-dimethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-
Butyl styrene, pn-hexyl styrene, pn-
Octyl styrene, pn-nonyl styrene, pn-
Examples thereof include decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chlorostyrene, and 3,4-dichlorostyrene. These monomers may be used alone or in combination of two or more.

Of these, styrene is particularly preferable. The ratio of styrene to the vinyl polymer is preferably 30 to 95% by weight, and particularly preferably 40 to 95% by weight. By selecting such a preferable ratio, the pulverization efficiency is increased in the pulverization step in the production of toner, and the toner having a desired particle size can be efficiently obtained.

Examples of the acrylic acid ester or methacrylic acid ester for obtaining the vinyl polymer include methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate. , 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α
-Acrylic acid esters such as methyl chloroacrylate;
For example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, methacrylic acid. Methacrylic acid esters such as dimethylaminoethyl and diethylaminoethyl methacrylate; and the like.

Examples of the carboxy group-containing compound that forms the half-ester compound include malonic acid, succinic acid, glutaric acid, and other aliphatic dicarboxylic acid compounds, and phthalic acid and other aromatic dicarboxylic acid compounds. A half-ester compound can be obtained by subjecting these compounds to an esterification reaction of an acrylic acid ester or a methacrylic acid ester having a hydroxyl group or a derivative thereof. The dicarboxylic acid compound may have a hydrogen atom substituted with a halogen group element, a lower alkyl group, an alkoxy group, or the like, or may be an acid anhydride.

The acrylic acid or methacrylic acid derivative having a hydroxyl group may be acrylic acid or methacrylic acid to which 1 mol or 2 mol or more of alkylene oxide such as ethylene oxide or propylene oxide is added, or acrylic acid or methacrylic acid. It may be a hydroxyalkyl ester obtained by esterifying an acid with a dihydric alcohol such as propylene glycol.

In the present invention, a compound represented by the following general formula (A) is used as the half-ester compound.

General formula (A) However, in the general formula (A), L represents a divalent bonding group having an ester bond in the molecular chain and having 3 or more carbon atoms, and may have a substituent. R ¹ represents a hydrogen atom or a methyl group.

More preferable half-ester compounds are represented by the following general formulas (1) to (4).

General formula (1) However, in the general formula (1), R ² and R ³ represent a hydrogen atom or a methyl group, m represents an integer of 1 to 14, and n represents an integer of 0 to 8.

General formula (2) However, in the general formula (2), R ⁴ and R ⁵ represent a hydrogen atom or a methyl group, h represents an integer of 1 to 14, X represents a hydrogen atom,
It represents a halogen group element, a lower alkyl group, or an alkoxy group.

General formula (3) However, in the general formula (3), R ⁶ represents a hydrogen atom or a methyl group, j represents an integer of 3 to 6, and k represents an integer of 0 to 8.

General formula (4) However, in the general formula (4), R ⁷ represents a hydrogen atom or a methyl group, i represents an integer of 3 to 6, and Y represents a hydrogen atom, a halogen group element, a lower alkyl group, or an alkoxy group.

Among the half-ester compounds represented by the general formulas (1) to (4), those represented by the general formula (1) are particularly preferable.

Examples of the half-ester compound represented by the general formula (1) include succinic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxypropyl ester, glutaric acid monoacryloyloxyethyl ester, and phthalic acid monoacryloyloxyethyl ester.
Phthalic acid monoacryloyloxypropyl ester, succinic acid monomethacryloyloxyethyl ester, succinic acid monomethacryloyloxypropyl ester,
Examples thereof include glutaric acid monomethacryloyloxyethyl ester, phthalic acid monomethacryloyloxyethyl ester, and phthalic acid monomethacryloyloxypropyl ester.

Polymerization of a half-ester compound obtained by an esterification reaction of the above-mentioned styrene-based monomer, acrylic acid ester-based monomer or methacrylic acid ester-based monomer, hydroxyl group-containing acrylic acid or methacrylic acid-based derivative and dicarboxylic acid compound The vinyl polymer having a carboxy group, obtained as described above, has a content ratio of the monomer unit of preferably 30 to 95% by weight, and particularly preferably 40 to 95% by weight of the styrene monomer. , Acrylic acid ester-based monomer or methacrylic acid ester-based monomer is preferably 70 to 5% by weight, particularly preferably 5 to 50% by weight,
The amount of the half-ester compound is preferably 0.5 to 30% by weight, particularly preferably 1 to 20% by weight.

When the content ratio of the acrylic acid ester-based monomer or the methacrylic acid ester-based monomer exceeds 70% by weight, or when the content ratio of the half-ester compound is less than 0.5% by weight, at the time of high-temperature fixing Offset resistance may decrease, and blocking resistance and plasticizer resistance may decrease.

The metal element of the polyvalent metal compound to react with the carboxy group of the vinyl polymer having a carboxy group, Cu, Ag, Be, Mg, Ca, Sr, Ba, Zn, Cd, Al, Ti, Ge, Sn, V, Cr, M
Examples include o, Mn, Fe, Ni, Co, Zr, Se and the like. Among these, alkaline earth metals (Be, Mg, Ca, Sr, Ba) and zinc group elements (Zn, Cd) are preferable, and Mg and Zn are particularly preferable.

As the polyvalent metal compound containing these metals, for example,
Of the above metal elements, fluoride, chloride, chlorate, bromide, iodide, oxide, hydroxide, sulfide, sulfite,
Lower alkyl metal compounds such as sulfates, selenides, tellurides, nitrides, nitrates, phosphides, phosphinates, phosphates, carbonates, orthosilicates, acetates, oxalates, methyl compounds or ethyl compounds Etc. can be mentioned. Of these, acetates of the above metal elements and oxides of the above metal elements are particularly preferable.

The amount of the polyvalent metal compound added cannot be unconditionally specified because it varies depending on the type and amount of the monomer constituting the vinyl polymer having a carboxy group. 0.1 to 1 for mol
It is about molar.

To react the polyvalent metal compound with the carboxy group of the vinyl polymer having a carboxy group, for example, in a solution containing a vinyl polymer having a carboxy group obtained by polymerizing by a solution polymerization method, Mix the polyvalent metal compound or the dispersion solution of the polyvalent metal compound, raise the temperature and remove the solvent for about 1 to 3 hours, and in the state where the temperature reaches about 150 to 180 ° C for 1 hour. The reaction is preferably completed by maintaining this temperature. In some cases, a polyvalent metal compound may be allowed to be present in the reaction system together with a solvent before the polymerization of the vinyl polymer having a carboxyl group, or a carboxy group obtained by performing the desolvation. You may make it react by melt-kneading the vinyl-type polymer which has and a polyvalent metal compound with a roll mill, a kneader, an extruder, etc.

In this way, the specific vinyl-based copolymer obtained by reacting the vinyl-based polymer having a carboxy group and the polyvalent metal compound, the carboxy group of the vinyl-based polymer and the polyvalent metal atom are ions. They are bound by a bond, and this ionic bond forms a kind of crosslinked structure. This ionic bond is a much slower bond than a covalent bond.

The specific vinyl copolymer has at least two local maxima in the molecular weight distribution curve as described above, but the method for obtaining such a copolymer is not particularly limited. For example, the first stage polymerization for obtaining either the high molecular weight component or the low molecular weight component is carried out, and one component thus obtained is dissolved in the monomer composition for obtaining the other component. Then, the second stage polymerization is carried out, whereby the other component is produced,
As a result, a polymer having at least two local maxima in the molecular weight distribution curve can be obtained. 2 like this
It is presumed that the polymer obtained by stage polymerization is a mixture of a low molecular weight component and a high molecular weight component uniformly at the molecular level.

This two-stage polymerization can be performed by, for example, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, etc., but a solution polymerization method is particularly preferable.

Further, the polymer having at least two local maximum values in the molecular weight distribution curve can be also obtained by mixing a low molecular weight polymer component and a high molecular weight polymer component, but the polymer obtained by mixing May not be uniformly mixed at the molecular level, so that the above two-stage polymerization is preferred.

Examples of colorants include carbon black, nigrosine dye, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, These mixtures, etc. can be mentioned.

Examples of the charge control agent include metal complex dyes, nigrosine dyes, ammonium compounds and the like.

Examples of the fixing property improving aid include polyolefins such as polyethylene and polypropylene. In particular, a polyolefin having a softening point Tsp by the ring and ball method of 70 to 150 ° C. is preferable, and further, the softening point Tsp thereof is 120 to 15
A 0 ° C. polyolefin is preferred.

In the electrostatic image developer of the present invention, the toner particles and the organic fine particles may further contain inorganic fine particles as a fluidity improver and an abrasive. The average diameter of the primary particles of such inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. Further, the specific surface area by the BET method is preferably 20 to 500 m ² / g. The amount of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.
01 to 2.0% by weight is preferred.

Specific examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate,
Zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide,
Examples thereof include silicon nitride. In particular, fine powder of silica is preferable.

As the fine powder of silica, those having a hydrophobic group on the surface are particularly preferable, and for example, "Aerosil R-972", "Aerosil R-974", "Aerosil R-805", "Aerosil R-812" (above, Commercially available products such as "Aerozil Japan" and "Taranox 500" (Tarco) can be preferably used. In addition to these, it is also possible to use a fine powder of silica surface-treated with a silane coupling agent, a titanium coupling agent, a silicone oil, a silicone oil having an amine in a side chain, or the like.

Further, in the electrostatic image developer of the present invention, a cleaning property improving agent may be further added and mixed. Examples of such a cleaning property improver include zinc stearate, calcium stearate, stearic acid and other aliphatic metal salts, such as polymer particles such as methyl methacrylate particles and styrene particles.

Further, when the magnetic toner is used, fine particles of magnetic material are contained in the toner particles. As such a magnetic material, iron,
Ferrite, magnetite and other iron, nickel, cobalt, and other ferromagnets or alloys, or compounds containing these elements, but which do not contain ferromagnetism, but exhibit ferromagnetism by appropriate heat treatment Alloys such as manganese-copper-aluminum, manganese-
Examples include alloys of the type called Heusler alloys containing manganese such as copper-tin and copper, chromium dioxide, and the like. It is preferable that the magnetic substance is uniformly dispersed and contained in the form of fine powder having an average particle diameter of 0.1 to 1 μm. The content ratio of the magnetic substance is preferably 10 to 70 parts by weight, and particularly preferably 20 to 50 parts by weight, based on 100 parts by weight of the toner.

In the case of a two-component developer, the developer is basically formed by mixing carrier particles together with the toner particles and the organic fine particles as described above. Such a carrier is not particularly limited, and a conventionally known carrier can be used. Specifically, a carrier composed of only magnetic particles, a resin-coated carrier in which the surface of each magnetic particle is coated with a resin, or the like can be used.

The magnetic particles forming the carrier include substances that are strongly magnetized in that direction by a magnetic field, such as iron and ferrite.
Metals or alloys showing magnetism such as iron, nickel, cobalt, etc. such as magnetite, compounds containing these elements, alloys containing no ferromagnetic elements but becoming ferromagnetic by proper heat treatment, for example, Particles composed of an alloy of the type called Heusler alloy such as manganese-copper-aluminum or manganese-copper-tin, or chromium dioxide can be used.

As the resin for coating the carrier, a fluororesin, a styrene resin, an acrylic resin, a styrene / acrylic copolymer resin or the like can be used.

The average particle size of the carrier is preferably 20 to 120 μm, and particularly preferably 30 to 110 μm. Here, the average particle size (weight) of the carrier is a value measured using "Microtrac" (manufactured by Nikkiso Co., Ltd.).

According to the electrostatic image developer of the present invention, an image can be formed as follows, for example. That is, in electrophotography, the electrostatic latent image formed on the latent image carrier is developed with an electrostatic image developer, and the obtained toner image is electrostatically transferred onto a transfer material such as paper. Then, the transfer toner is fixed by a heating roller fixing method, and thus a fixed image is formed.

The heating roller fixing device used in the heating roller fixing method is usually composed of a heating roller, a pressure bonding roller arranged in contact with the heating roller, and a heat source. Further, a cleaning roller is arranged in contact with the heating roller as needed. While the temperature of the heating roller is kept within a certain range by the heating source, the transfer material on which the toner has been transferred is passed between the heating roller and the pressure bonding roller, so that the toner directly contacts the heating roller and the toner Is thermally fixed to the transfer material. The surface material of the heating roller is preferably a fluorine-based material or a silicone-based material, and the synergistic effect with the electrostatic image developer of the present invention can remarkably improve the durability of the heating roller fixing device.

〔Example〕

Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

<Manufacture of Binder Resin> (1) Binder Resin B1 (for the Present Invention) Toluene 50 in a separable flask having a capacity of 3 and equipped with a thermometer, a stirrer, a nitrogen gas introducing tube, and a flow-down condenser.
After adding 0 ml and introducing a nitrogen gas through a nitrogen gas introducing tube to make the inside of the flask an inert atmosphere, the flask was heated in an oil bath to the reflux temperature of toluene.

Then 210 g of styrene, 60 g of n-butyl acrylate,
Methyl methacrylate 30g, benzoyl peroxide
A composition of 0.9 g of a high molecular weight component was placed in a flask, kept at the reflux temperature and reacted for 14 hours to form a high molecular weight polymer.

Next, in a flask containing the solution of the high molecular weight polymer, styrene 417 g, α-methyl styrene 35 g, n-butyl acrylate 105 g, methyl methacrylate 70 g, monoacryloyloxyethyl succinate 73 g, and benzoyl peroxide 42 g were added. The polymerization reaction was carried out while gradually dropping the composition of the low molecular weight component. After the dropping of the composition of the low molecular weight component was completed, a polymerization reaction was further performed for 4 hours to form a low molecular weight polymer.

Next, in a flask containing a solution of the high molecular weight polymer and the low molecular weight polymer, zinc oxide which is a polyvalent metal compound is placed.
8 g was added, and the reaction was carried out for 2 hours while stirring at the reflux temperature.

After completion of the reaction, the solvent toluene was distilled off under reduced pressure,
A binder resin B1 obtained by reacting a carboxy group of a low molecular weight component with a polyvalent metal compound was obtained.

This binder resin B1 is gel permeation chromatography (HLC-802UR, GMH ₆ column, manufactured by Toyo Soda Co., Ltd.)
7.5 × 10 ³ and 2.8 × 10 ⁵ in the molecular weight distribution curve by
Has a maximum value, and the weight average molecular weight Mw is 1.2 × 1
0 ⁵ , the ratio Mw / Mn is 17.1, and the glass transition point Tg is 56 ° C.

(2) Binder resin B2 (for the present invention) In the production of the binder resin B1, styrene 180 g, n-butyl acrylate 30 g, n-
Butyl methacrylate 60g, methyl methacrylate 30g,
Using a composition consisting of 1.5 g of azobisisobutyronitrile, styrene 442 g, α-
Methyl styrene 70g, 2-ethylhexyl acrylate 1
Using a composition consisting of 05 g, metal methacrylate 35 g, monoacryloyloxyethyl isophthalate 48 g, and benzoyl peroxide 28 g, as a polyvalent metal compound,
A binder resin B2 obtained by reacting a carboxy group of a low molecular weight component with a polyvalent metal compound was obtained in the same manner as in the production of the binder resin B1 except that 22.4 g of zinc acetate was used.

This binder resin B2 has maximum values at 1.2 × 10 ⁴ and 2.4 × 10 ⁵ , respectively, in the molecular weight distribution curve by gel permeation chromatography, and has a weight average molecular weight.
Mw is 1.15 × 10 ⁵ , ratio Mw / Mn is 9.5, glass transition temperature Tg is 5.
8 ° C.

(3) Binder resin b1 (for comparison) Binder resin b1 for comparison was prepared in the same manner as in binder resin B1, except that zinc oxide, which is a polyvalent metal compound, was not used.
Got

This binder resin b1 has maximum values at 7.1 × 10 ³ and 2.8 × 10 ⁵ , respectively, in the molecular weight distribution curve by gel permeation chromatography, and has a weight average molecular weight.
Mw is 1.18 × 10 ⁵ , ratio Mw / Mn is 18.1, glass transition point Tg is
It is 53 ° C.

<Manufacture of Toner Particles> (1) Toner Particles T1 (for the Present Invention) 100 parts by weight of the binder resin B1, 10 parts by weight of carbon black “Mogal L” (manufactured by Cabot), and polypropylene “Viscol 660P” ( (Softening point Tsp: 145 ° C, manufactured by Sanyo Kasei Kogyo Co., Ltd.) 3 parts by weight are mixed with a V-type blender, melt-kneaded with a two-roll mill, cooled, coarsely crushed with a hammer mill, and finely pulverized with a jet mill. After doing
The particles were classified by an air classifier to obtain toner particles T1 having a particle size of 1 to 30 μm.

(2) Toner particles T2 (for the present invention) In the production of toner particles T1, the binder resin B1 is replaced with the binder resin B2.
Toner particles T2 were obtained in the same manner except that the above was changed to.

(3) Toner particles t1 (for comparison) In the production of the toner particles T1, the binder resin B1 is replaced with the binder resin b1.
Comparative toner particles t1 were obtained in the same manner except that

<Manufacture of Organic Fine Particles> (1) Organic Fine Particles A1 Emulsion polymerization of potassium persulfate and sodium thiosulfate as initiators and methylmethacrylate without an emulsifier was performed to obtain organic fine particles A1 having an average primary particle diameter of 0.4 μm. Obtained.

(2) Organic fine particles A2 Organic fine particles having an average primary particle diameter of 0.8 μm in the same manner except that in the organic fine particles A1, 95 parts by weight of methyl methacrylate and 5 parts by weight of n-butyl acrylate were used instead of methyl methacrylate. I got A2.

(3) Organic fine particles A3 Organic fine particles A3 having an average primary particle diameter of 0.6 μm were similarly used except that 92 parts by weight of methyl methacrylate and 8 parts by weight of ethyl acrylate were used instead of methyl methacrylate in the organic particles A1. Obtained.

<Production of Carrier Particles> Carrier particles C1 obtained by coating the surfaces of copper-zinc ferrite particles with a styrene-methyl methacrylate copolymer (monomer composition; styrene: methyl methacrylate = 70: 30) were obtained. The average particle size of the carrier particles C1 is 82μ.
It was m.

<Preparation of Developer> Toner particles and organic fine particles were mixed in a V-type blender in the combinations and proportions shown in Table 1 below, and further mixed with carrier particles to prepare respective developers.

<Actual photo test> Each of the above was performed by a modified machine of an electrophotographic copying machine "U-Bix1600" (manufactured by Konishi Rokusha Kogyo KK) equipped with a developing device for two-component developer, a cleaning device having a cleaning blade, and a heating roller fixing device. An electrostatic latent image is developed using a developer, the obtained toner image is transferred onto a transfer paper, and then fixed by a heating roller fixing device to form a copied image. did. The results are shown in Table 2 below.

Fixability under low temperature and low humidity environment Under low temperature and low humidity environment conditions (temperature 10 ℃, relative humidity 40%), the set temperature of the heating roller fixing unit (usually 180 ℃) is 150
While the temperature was lowered to ℃, 100 continuous live-photographing tests were performed, and the 100th copy image was rubbed with Kimwipe to determine the fixability. In the evaluation, "○" was given when the rubbing resistance was sufficient, "△" was given when it was slightly inferior, and "x" was given when the image was significantly peeled off. The heating roller fixing device does not have a silicone oil supply mechanism.

Durability of fixing unit under low temperature and low humidity environment Under low temperature and low humidity environment conditions (temperature 10 ° C, relative humidity 40%), the set temperature of the heating roller fixing unit was lowered to 150 ° C.
The actual copying test was carried out over 00,000 times, and the durability of the fixing device was judged by examining the dirt of the heating roller, the dirt of the pressure bonding roller, the anti-offset property and the dirt on the back surface of the transfer paper. In the evaluation, good ones were evaluated as “◯”, slightly inferior but practical levels were evaluated as “Δ”, and poor ones that were practically problematic were evaluated as “x”.

Blocking resistance under high-temperature and high-humidity environment conditions.
%) For 1 week, and judged according to whether or not agglomerates were generated in the toner particles. The case where almost no agglomerates were observed was marked with “◯”, the case where a few agglomerates were observed was marked with “Δ”, and the case where agglomerates were significantly generated was marked with “x”.

Filming resistance under high-temperature and high-humidity environment conditions Under high-temperature and high-humidity environment conditions (temperature 33 ° C, relative humidity 80%), after 100,000 continuous shooting tests, carrier particle surface and latent image bearing The surface of the body and the cleaning blade were observed with an electron microscope or visually, and the presence or absence of the adhered matter was judged. The case where the adhered matter was not recognized was marked with “◯”, the case where the adhered matter was slightly recognized was marked with “Δ”, and the case where the adhered matter was significantly recognized was marked with “x”.

Cleanability Under high temperature and high humidity environmental conditions (temperature 33 ° C, relative humidity 80%), 100,000 continuous live-copy tests were conducted.
Every time the number of times of image formation reached 5,000 times, the surface of the latent image bearing member after being cleaned by the cleaning blade was visually observed and judged by the presence or absence of the adhered matter. In the evaluation, good ones were evaluated as “◯”, slightly inferior but practical levels were evaluated as “Δ”, and inferior and practically problematic were evaluated as “x”.

Image quality (durability) Under high temperature and high humidity environment conditions (temperature 33 ° C, relative humidity 80%), 100,000 continuous live-copy tests were performed, and the sharpness of copied images was examined at the initial stage of image formation and after 100,000 times. . In the evaluation, good ones were evaluated as “◯”, slightly inferior but practical levels were evaluated as “Δ”, and considerably inferior and practically problematic were evaluated as “x”.

As can be understood from the results in Table 2, the developers 1 to 4 of the present invention are excellent in low-temperature fixing property and anti-offset property. A good fixed image can be stably formed many times without stains, and since it has excellent blocking resistance, filming resistance, and cleaning properties, there is no fog even under high temperature and high humidity environment conditions. A clear image can be stably formed many times.

On the other hand, in Comparative Developer 1, since the binder resin b1 is not cross-linked by the polyvalent metal compound, the offset resistance is poor and the heating roller is significantly soiled under low temperature and low humidity environment conditions. However, as a result, troubles such as paper jams are likely to occur at an early stage. Further, under high temperature and high humidity environment conditions, fogging occurs early and the image becomes unclear, resulting in low durability.

Further, since the comparative developer 2 does not have organic fine particles, it is inferior in filming resistance and cleaning property under high temperature and high humidity environment conditions, fog occurs at an early stage, an image becomes unclear, and durability is low. Is.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuuki Okuyama 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock company (72) Hiroyuki Yamada 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock company (56 ) Reference JP 61-110156 (JP, A) JP 61-110155 (JP, A) JP 57-178250 (JP, A) JP 56-158340 (JP, A)

Claims (2)

[Claims] 1. Toner particles (a) containing an ionically cross-linked vinyl copolymer as a binder resin, and 0.01 to 3 parts by weight of organic fine particles (100 parts by weight of the toner particles (a)). (2) An electrostatic image developer comprising: the binder resin having a molecular weight distribution of at least two groups of a low molecular weight component and a high molecular weight component, and in the molecular weight distribution, the low molecular weight The maximum value of the component is in the range of 1 × 10 ³ to 2 × 10 ⁴ , the maximum value of the high molecular weight component is in the range of 1 × 10 ⁵ to 2 × 10 ⁶ , and the binder resin is a) a styrene-based monomer, (b) a polymer obtained from an acrylic acid ester-based monomer or a methacrylic acid ester-based monomer, and (c) a carboxy group-containing monomer represented by the following general formula (A): A cross-linked polymer obtained by reacting with a polyvalent metal compound, Machine microparticles (B) is spherical, the average diameter of the primary particles
An electrostatic image developer comprising a vinyl polymer having a thickness of 0.01 to 5 μm. General formula (A) (In the formula, R ¹ represents a hydrogen atom or an ethyl group, L represents a divalent bonding group having 3 or more carbon atoms and having an ester bond in the molecular chain, and may have a substituent.) 2. The electrostatic image developer according to claim 1, wherein the polyvalent metal compound is a zinc group metal compound or an alkaline earth metal compound.