JP3185079B2 - Development method - 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 developing method for developing an electrostatic image in electrostatic printing, magnetic recording, and the like.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
JP-A (U.S. Pat. No. 3,666,363) and JP-B-43-24748 (U.S. Pat.
Many methods are known, for example, an electric latent image is formed on a photoreceptor by various means using a photoconductive substance, and then the latent image is developed. The toner image is developed using powder (hereinafter, referred to as toner), and if necessary, a toner image is transferred to a transfer material such as paper, and then fixed by heating, pressure, or solution vapor to obtain a copy. . In the case where a step of transferring a toner image is provided, a step for removing residual toner on the photoconductor is usually provided.

A method for visualizing an electric latent image using toner is described in, for example, a magnetic brush method described in US Pat. No. 2,874,063, and US Pat. No. 2,618,552.
Cascade development method described in
221 and 776, there is a powder cloud method and the like. US Pat. No. 3,909,258 discloses a method using a magnetic toner, a method using a conductive toner, a method using a dielectric polarization of toner particles, and a method using a magnetic toner. Charge transfer method Also, in recent years, Japanese Patent Application Laid-Open No.
No. 1, JP-A-55-18656, there is a method of developing a latent image by flying toner particles.

As a toner applied to these developing methods, particles obtained by finely pulverizing a dispersion of a dye or a pigment in a natural or synthetic resin to about 1 to 30 μm have been used as the toner. As the magnetic toner, a toner containing magnetic particles such as magnetite is used. In the case of a system using a so-called two-component developer,
The toner is usually used by mixing with carrier particles such as glass beads and iron powder.

[0005] In such a method using a dry developer, in order to form a visible image of good quality, it is necessary that the developer has high fluidity and uniform chargeability. For that purpose, conventionally, silicic acid fine powder has been added to and mixed with toner powder. Anyway,
Since silica fine powder is hydrophilic as it is, the developer to which it is added causes aggregation due to moisture in the air, causing a decrease in fluidity or, in extreme cases, silica fine powder. , The charging characteristics of the developer are degraded.

Therefore, use of fine silica powder subjected to a hydrophobizing treatment is disclosed in JP-A-46-5782 and JP-A-48-5782.
47345, JP-A-48-47346, and the like. Specifically, for example, silicic acid fine powder obtained by reacting a silicic acid fine powder with an organosilicon compound such as dimethyldichlorosilane, and substituting a silanol group on the surface of the silicic acid fine powder with an organic group to make it hydrophobic is used. I have. JP-A-63-139367 proposes a method in which fine silica powder is treated with a silane coupling agent and then further treated with silicone oil. Japanese Patent Application Laid-Open No. 3-145563 proposes a method using a hydrophobic fine silica powder that has been subjected to a hydrophobic treatment with a polymethylsilyl group.

On the other hand, in order to fix a recording material with low power consumption and obtain a high-quality image, improvement of a binder resin satisfying the contradictory properties of low-temperature fixability and offset resistance has been attempted. JP-A-63-214760, 63
JP-A-217362, JP-A-63-217363,
JP 63-217364 A discloses that a carboxylic acid group having a molecular weight distribution divided into two groups of a low molecular weight and a high molecular weight is reacted with a polyvalent metal ion contained on the low molecular weight side. . Further, JP-A-2-1682
JP-A-46-235 and JP-A-2-23569 disclose that the low molecular weight component and the high molecular weight component in the binder resin are further polarized and the high molecular weight component contains a carboxyl group.

[0008] However, when these binder resins are used together with the above-mentioned hydrophobized silica fine powder,
Although the performance is improved with respect to the fixing property, the anti-offset property, and the cleaning property of the toner, the property tends to be agglomerated and the fluidity is impaired. Further, the dispersion state of each component in the developer was insufficient, and it was difficult to obtain stable developability. In particular, since the releasability from the photoreceptor is insufficient, a part of the image is missing, that is, a so-called "hollow" phenomenon is caused. Further, as image printing is continued, the developer is fused to a member such as a photoreceptor or the like, thereby causing an image defect.

[0009]

That is, an object of the present invention is to provide a developing method capable of always exhibiting good characteristics when a binder resin for low-temperature fixing is used.

Another object of the present invention is to provide a developing method capable of obtaining a good image without a so-called hollow phenomenon.

Still another object of the present invention is to provide a developing method which does not cause image defects caused by fusing a developer to a photoreceptor.

[0012]

SUMMARY OF THE INVENTION According to the present invention, an electrostatic latent image formed on a photosensitive drum is spaced from the photosensitive drum so that the developer layer on the developer carrier is not in contact with the photosensitive drum. Set,
In a developing method in which an AC bias and a DC bias are applied to the developer carrying member to perform development, the developer for forming the developer layer includes toner particles containing a binder resin and a colorant, and a silane cup. After being treated with a ring agent, furthermore, methyl hydrogen silicone oil, or
A mixture of silicone oil containing 10% by weight or more of methyl hydrogen silicone oil or fine silica powder treated with a silicone varnish admixture, wherein the binder resin is prepared by a solution polymerization method using (a) a vinyl monomer. (B) 100 parts by weight of a vinyl monomer and 0.001 to 0.01 of a crosslinkable monomer
A high-molecular-weight resin synthesized by a suspension polymerization method using a polyfunctional initiator and a monofunctional initiator in combination in a weight part is mixed in a solution state in the presence of a solvent, and then manufactured by a solution blending method in which the solvent is removed. The chromatogram of the binder resin measured by gel permeation chromatography has a main peak in the molecular weight region of 2,000 to 30,000, and has a main peak in the high molecular weight region of 100,000 or more. The present invention relates to a developing method having a subpeak or a shoulder and having a weight average molecular weight (Mw) / number average molecular weight (Mn) of 30 or more.

The present inventors consider the reason why the developer according to the present invention exerts the effects of the present invention as follows.

That is, the Si—H bonds of the methyl hydrogen silicone oil are oxidized by oxygen in the air during the heat treatment process to form new siloxane bonds with the Si—H bonds of other adjacent molecules. This gives 3
It is thought that silicone oil molecules grew in a three-dimensional network, and a more prominent and effective hydrophobic treatment was performed.

The binder resin used in the present invention has a molecular weight of 2,000 to 30,0 in a GPC chromatogram.
A main peak in the 00 region, a subpeak or shoulder in the high molecular weight region of 100,000 or more, and a weight average molecular weight (Mw) / number average molecular weight (Mn) of 30 or more;
The polymer region has a crosslinkable monomer unit as a constituent monomer unit and contains a polymer having a Mw of 1.2 million or more, which is polymerized by using a polyfunctional initiator and a monofunctional initiator in combination. Is what you do.

Further, the high molecular component constituting the binder resin contains a reactive polar group in an acid value range of more than 1.0. More preferably, it is 5.0 or more. Acid value ≦ 1.
In the case of 0, a sufficient crosslinked structure cannot be constructed,
Various problems are caused by the deterioration of the offset resistance and the decrease in the dispersibility of each component in the developer.

The glass transition temperature of the binder resin is 55 to 70 ° C., preferably 60 to 60 ° C., from the viewpoint of the storage stability of the developer.
６５65 ° C. and the glass transition temperature is lower than 55 ° C.,
Deterioration due to blocking of the developer in a high-temperature atmosphere and hot offset in a high-temperature region occur. On the other hand, when the temperature exceeds 70 ° C., the overall fixability is adversely affected.

Further, the blending ratio of the high molecular weight component and the low molecular weight component also greatly affects the fixing characteristics of the developer. If the hot offset occurs and exceeds 45%, the fixability in a low temperature range deteriorates. Therefore, in the present invention, the ratio of the high molecular weight to the entire binder resin needs to be 15 to 45%, and preferably needs to be restricted to the range of 20 to 40%.

In the present invention, the molecular weight of the peak of the chromatogram by GPC is measured under the following conditions.

That is, the column is stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) as a solvent is flowed through the column at this temperature at a flow rate of 1 ml per minute, and the sample concentration is 0.05 to 0.6% by weight. Inject 50-200 μl of the THF sample solution of the resin adjusted to above and measure. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. Standard polystyrene samples for preparing a calibration curve include, for example, Pressure Chemical C
o. Or Tosoh Corporation has a molecular weight of 6 × 10 ² , 2.1
× 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 1
^{0 4, 1.1 × 10 5,} 3.9 × 10 5, 8.6 × 10
^It is suitable to use ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ and at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

In addition, as the column, 10 ³ -4 × 10
^In order to accurately measure the molecular weight region of ^6, a plurality of commercially available polystyrene gel columns may be combined. For example, μ-styragel 500, 1 manufactured by Waters, Inc.
0 ³ , 10 ⁴ , 10 ⁵ , and Shodex KF-80M and KF-802, 803 manufactured by Showa Denko KK
804, 805, or Tosoh T
SKgel G1000H, G2000H, G2500
H, G3000H, G4000H, G5000H, G6
A combination of 000H, G7000H, and GMH is preferred.

The weight ratio of the low molecular weight component to the high molecular weight component of the binder resin according to the present invention is determined by the area of the low molecular weight side peak portion and the high molecular weight side peak portion based on the minimum value between the peaks in the chromatogram of GPC. Calculate from the ratio.

The polymer component having a polar group capable of forming a cross-linking bond of the present invention generally has a carboxyl group, a carbonyl group, an ether group, a thioether group, an amino group, an amide group, a hydroxyl group and the like. Among them, a polymer containing a carboxyl group shows the best reactivity. Examples of the carboxyl group-containing monomer for synthesizing the vinyl polymer include acrylic acid, methacrylic acid, α-ethylacrylic acid, acrylic acid such as crotonic acid and α- or β-alkyl derivatives thereof, fumaric acid,
There are unsaturated dicarboxylic acids such as maleic acid and citraconic acid and monoester derivatives thereof, and such a monomer can be used alone or as a mixture and copolymerized with other monomers to produce a desired polymer. . Among them, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid.

The carboxyl group-containing monomer which can be used in the present invention includes, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate,
Monoesters of α, β-unsaturated dicarboxylic acids such as monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate, etc .; monobutyl n-butenylsuccinate, monomethyl n-octenylsuccinate, Monoesters of alkenyl dicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenylglutarate and monobutyl n-butenyladipate; monomethyl phthalate, monoethyl phthalate, monobutyl phthalate and the like And monoesters of aromatic dicarboxylic acids.

The reason why the monoester monomer of dicarboxylic acid is selected as described above will be described in detail later, because the suspension polymerization method is preferable as the method for producing the resin. This is because, in the suspension polymerization, it is not appropriate to use an acid monomer having a high solubility in an aqueous suspension, and it is preferable to use an ester having a low solubility in an ester.

Examples of the monomer for obtaining the high-molecular component and the low-molecular component of the binder resin used on the developing side of the present invention include the following.

For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
Styrene such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylene , Ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Stearyl, meta Phenyl acrylic acid, dimethylaminoethyl methacrylate, alpha-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate;
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, propyl acrylate,
Acrylic esters such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds of vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; used alone or in combination of two or more.

Among these, a combination of monomers that will result in a styrene-based copolymer and a styrene-acrylic copolymer is preferred.

As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used.

The binder resin used in the present invention must be a polymer cross-linked with a cross-linkable monomer as exemplified below in order to achieve the object of the present invention.

Aromatic divinyl compounds, for example, divinylbenzene, divinylnaphthalene, etc .; diacrylate compounds linked by an alkyl chain; for example, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol Diacrylate,
1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylates; diacrylate compounds linked by an alkyl chain containing an ether bond , Such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds instead of methacrylate Diacrylate compounds linked by a chain containing an aromatic group and an ether bond, for example, polyoxyethylene (2) -2,2-bis ( - hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,
2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing the acrylates of the above compounds with methacrylates; further, polyester-type diacrylate compounds, for example, trade name MANDA (Nippon Kayaku) . As multifunctional crosslinking agents, pentaerythritol acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and acrylates of the above compounds to methacrylate Alternatives; triallyl cyanurate, triallyl trimellitate; and the like.

These cross-linking agents are used in combination with other monomer components 10
It is preferable to use 0.001 to 1% by weight, preferably 0.003 to 0.01% by weight, based on 0% by weight.

Among these crosslinkable monomers, those which are preferably used in the developer resin from the viewpoint of fixing properties and anti-offset properties include aromatic divinyl compounds (particularly divinylbenzene), aromatic groups and ether bonds. And diacrylate compounds linked by a chain containing the same.

As a method for producing the binder resin according to the present invention, a high-molecular-weight polymer and a low-molecular-weight polymer are separately synthesized, then mixed in a solution state, and then the solvent is removed. A low-molecular-weight polymer obtained by a solution blending method or the like is melted and kneaded by a melter or the like, and the low-molecular-weight polymer is dissolved in a monomer constituting a high-molecular-weight polymer, suspension polymerization is performed, and water washing and drying are performed. And a two-stage polymerization method for obtaining a resin for adhesion. However, the dry blending method has problems in terms of uniform dispersion and compatibility.
Although the step polymerization method has many advantages such as uniform dispersibility, it is not possible to increase the low molecular weight component to a high molecular weight component or more,
In the presence of a low molecular weight component, not only is it very difficult to synthesize a desired high molecular weight component desired in the present invention, but also there are disadvantages such as unnecessary low molecular weight components being by-produced. For this purpose, the solution blending method is most suitable.

As a method for synthesizing the low molecular weight component of the binder resin according to the present invention, a known method can be used. However, in the bulk polymerization method, a polymer having a low molecular weight can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control. In that regard, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer depending on the solvent, and by adjusting the amount of the initiator and the reaction temperature, It is preferable to obtain a low molecular weight compound in the resin composition used in the present invention. In particular, the solution polymerization method under a pressurized condition is effective in minimizing the amount of the initiator used and minimizing the influence of the initiator residue.

On the other hand, as a polymerization method which can be used in the present invention as a method for synthesizing the high molecular weight component of the binder resin according to the present invention, there are an emulsion polymerization method and a suspension polymerization method.

Among them, the emulsion polymerization method is a method in which a monomer almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. . In this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer)
And the aqueous phase are separate, so that the termination reaction rate is low, resulting in a high polymerization rate and a high degree of polymerization. Further, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
There is an advantage as a method for producing a binder resin for a toner because it is easy to mix with a colorant, a charge control agent and other additives.

However, the resulting polymer tends to be impure due to the added emulsifier, and an operation such as salting out is required to take out the polymer. To avoid this inconvenience, suspension polymerization is advantageous.

In the suspension polymerization, 100 parts by weight or less of the monomer (preferably 1 part by weight) is added to 100 parts by weight of the aqueous solvent.
(0 to 90 parts by weight). Examples of usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like. There is an appropriate amount in terms of the amount of a monomer relative to an aqueous solvent, and generally 0.05 to 1 based on 100 parts by weight of an aqueous solvent. Used in parts by weight. The polymerization temperature is suitably from 50 to 95 ° C, but should be appropriately selected depending on the initiator used and the intended polymer.

In the present invention, the polyfunctional initiator and the monofunctional initiator used in the synthesis of the high molecular weight polymer include:
Any water-insoluble or hardly water-soluble material can be used. They are used in an amount of 0.05 to 2.0 parts by weight based on 100 parts by weight of the monomer.

Specific examples of the polyfunctional polymerization initiator include:
1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4
-Bis (t-butylperoxy) valerate, 2,2-
Bis (t-butylperoxy) butane, 1,3-bis (t-butylperoxy-isopropyl) benzene,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-
2,5-di (benzoylperoxy) hexane, di-t
-Butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl)
Propane, di-t-butylperoxy α-methyl succinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, 2,5 −
Bifunctional radical polymerization initiators such as dimethyl-2,5-di (t-butylperoxy) -hexane, diethylene glycol-bis (t-butylperoxycarbonate) and di-t-butylperoxytrimethyl adipate; trifunctional radical polymerization initiators such as t-butylperoxy) triazine and vinyltolyl (t-butylperoxy) silane; 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, t- Butyl peroxyallyl carbonate copolymer compound (for example, Hyper B and Hyper G series manufactured by NOF Corporation), t-
And polyfunctional radical polymerization initiators such as a copolymerized compound of butylperoxymaleic acid.

In the present invention, the carboxylic acid groups and carboxylic acid ester sites in the copolymer obtained by the above method are subjected to an alkali treatment to be saponified. That is, it is preferable that the carboxylic acid group or the carboxylic acid ester moiety is changed to a polar functional group by reacting with a cation component of an alkali. Even if the polymer side component of the binder resin contains a carboxyl group that reacts with the metal-containing compound, the efficiency of the cross-linking reaction with the metal-containing compound decreases when the carboxyl group is dehydrated, that is, in a ring-closed state. Because you do.

This alkali treatment may be carried out after the production of the binder resin, by introducing it as an aqueous solution into the solvent used during the polymerization and stirring. Examples of the alkali that can be used in the present invention include Na, K, Ca, Li, Mg, and Ba.
Hydroxides of alkali metals and alkaline earth metals such as;
There are hydroxides of transition metals such as Zn, Ag, Pb, and Ni; hydroxides of quaternary ammonium salts such as ammonium salts, alkylammonium salts, and pyridium salts. Particularly preferred examples include NaOH and KOH. .

In the present invention, the saponification reaction does not need to be carried out over all of the carboxylic acid groups and carboxylic acid ester sites in the copolymer. I just need to change.

The amount of the alkali used in the saponification reaction is difficult to determine unconditionally depending on the type of the polar group in the binder resin, the dispersion method, the type of the constituent monomers, and the like. What is necessary is just 02-5 times equivalent. When the amount is less than 0.02 equivalent, the saponification reaction is not sufficient, and the number of polar functional groups generated by the reaction decreases, and as a result, the subsequent metal crosslinking reaction becomes insufficient.
On the other hand, when the amount exceeds 5 times equivalent, the functional group such as a carboxylic acid ester site is adversely affected by hydrolysis of the ester, generation of a salt by a saponification reaction, and the like.

When an alkali treatment having an acid value of 0.02 to 5 equivalents is performed, the residual cation ion concentration after the treatment is included in the range of 5 to 1000 ppm, which is preferable for defining the amount of alkali. Can be used.

In the present invention, it is preferable to add a low molecular weight wax to the binder resin used in advance. Examples of the low molecular weight wax applicable to the present invention include wax-like substances such as polypropylene, polyethylene, microcrystalline wax, carnauba wax, sasol wax, paraffin wax, and oxides and graft-modified products thereof.

The weight average molecular weight of these low molecular weight waxes is preferably 30,000 or less, more preferably 10,000 or less, and the addition amount is about 2 to 100 parts by weight based on 100 parts by weight of the high molecular weight polymer component. preferable.

In the present invention, it is preferable to contain a metal-containing compound which causes a crosslinking reaction with the resin binder.
As the reactive metal compound used in the present invention, those containing the following metal ions can be used. Suitable monovalent metal ions include Na ⁺ , Li ⁺ , Cs ⁺ , Ag ⁺ , Hg ⁺ , C
u ⁺ etc., and divalent metal ions include Be ²⁺ , Mg
²⁺ , Ca ²⁺ , Hg ²⁺ , Sn ²⁺ , Pb ²⁺ , Fe ²⁺ , C
o ²⁺ , Ni ²⁺ , Zn ²⁺ and the like. Further, as trivalent ions, Al ³⁺ , Sc ³⁺ , Fe ³⁺ , Co ³⁺ , Ni ³⁺ ,
Cr ³⁺ and the like. Among the compounds containing metal ions as described above, the more decomposable, the better the results.
This is presumed to be due to the fact that the metal ion in the compound is more easily bonded to the carboxyl group in the polymer by the thermal decomposition in the decomposable one.

Among the reactive metal compounds, the organometallic compounds are excellent in compatibility and dispersibility with the polymer, and the crosslinking by the reaction with the metal compound proceeds more uniformly in the polymer, so that more excellent results are obtained. .

Among the reactive organometallic compounds as described above, those containing an organic compound having a high vaporization or sublimation property as a ligand or a counter ion are particularly useful. Among the organic compounds forming a ligand or a counter ion with a metal ion, those having the above properties include, for example, salicylic acid, salicylamide, salicylamine, salicylaldehyde, salicylosalicylic acid, ditert-butylsalicylic acid And salicylic acid and derivatives thereof, for example, β-diketones such as acetylacetone and propionacetone, and low-molecular carboxylic acid salts such as acetate and propionic acid.

It is also possible for the metal complex to have charge controllability of toner particles. As such a metal complex, there is an azo-based metal complex represented by the following general formula [I].

[0053]

Embedded image

Next, specific examples of the complex will be shown.

[0055]

Embedded image

[0056]

[0057]

[0058]

[0059]

[0060]

Alternatively, a basic organic acid metal complex represented by the following general formula [II] also gives a negative charge and can be used in the present invention.

[0062]

[0063]

Next, specific examples of the complex will be shown.

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

These metal complexes can be used alone or in combination of two or more.

The amount of the metal complex added to the toner particles varies depending on the type of the toner binder, whether or not the carrier is used in combination, the pigment for coloring the toner, and the reactivity of the metal complex with the binder. 0.01 to 100% by weight of binder, including unreacted ones
It is 20% by weight, preferably 0.1 to 10% by weight.

The metal complex reacts with the binder at the time of melt-kneading, so that it is more decomposed / reactive and more compatible with the binder or dispersible in the binder than when added during the synthesis of the binder. There is an advantage that the toner is excellent and a stable chargeability is obtained as a toner.

In the present invention, the metal compound as a cross-linking component can have charge controllability as a toner. However, if necessary, a charge control agent can be separately used. Conventionally known negative or positive charge control agents are used.

The charge control agents known in the art today include the following:

The following substances control the toner to be negatively charged.

For example, organic metal complexes and chelate compounds are effective and include the above-mentioned monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid-based metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The following substances control the toner to be positively charged.

Modified products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and phosphonium analogs thereof Onium salts such as salts and lake pigments thereof. Triphenylmethane dyes and their lake pigments. (As a rake agent,
Metal salts of higher fatty acids, such as phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, and ferrocyanide; metal complexes of acetylacetone. Diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate;
And diorganotin borates such as dicyclohexyl tin borate. These can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

The fine silica powder used in the present invention is a so-called dry method produced by the vapor phase oxidation of a silicon halide compound or dry silica called fumed silica.
And both of the so-called wet silica produced from water glass or the like is usable surface and having less silanol groups inside the silicate fine powder, also, Na ₂ O, without producing residual SO ₃ ^2-like Dry silica is preferred.

In the case of fumed silica, a composite fine powder of silica and another metal oxide can be obtained by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide in the production process. Yes, including them.

The average particle size of the particles is 0.0%.
It is preferable to use a silica fine powder in the range of 01 to 2 μm.

The silane coupling agent used in the present invention is represented by the general formula: RmSiYn R: alkoxy group or chlorine atom m: an integer of 1 to 3 Y: alkyl group Hydrocarbon group containing vinyl group, glycidoxy group, methacryl group n: Represented by an integer of 3 to 1, for example, typically, dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane , Γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, dimethylvinylchlorosilane and the like.

The silane coupling agent treatment of the silicic acid fine powder may be performed by a dry treatment in which a vaporized silane coupling agent is reacted with a cloud of the silicic acid fine powder by stirring or the like, or the silicic acid fine powder is dissolved in a solvent. And a generally known method such as a wet method in which a silane coupling agent is dropped and reacted.

The methyl hydrogen silicone oil used in the present invention has the following formula

[0090]

Embedded image

(Where m and n are both positive integers). The methyl hydrogen silicone oil preferably has a viscosity at 25 ° C. of about 10 to 50 centistokes.

Other silicone oils used in the present invention are generally represented by the following formula:

[0093]

Embedded image

[0094] R: C _{1 to 3} alkyl radicals R ': alkyl, halogen-modified alkyl, phenyl,
Silicone oils modified group R of the modified phenyl such as ": alkyl C _{1 to 3} or Arukookishi group m, n: positive integer

For example, dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil and the like can be mentioned. The silicone oil preferably has a viscosity at 25 ° C. of about 50 to 1000 centistokes.

If the molecular weight of these methyl hydrogen silicone oils and other silicone oils is too low, volatile components may be generated by heat treatment or the like. If the molecular weight is too high, the viscosity may become too high. It becomes difficult to remove.

In the present invention, the content of the methyl hydrogen silicone oil must be at least 10% by weight of the total silicone oil. If it is less than 10% by weight, the sufficient effect of the methyl hydrogen silicone oil cannot be obtained.

A known technique is used for the method of treating the silicone oil. For example, silica fine powder and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the silicone oil may be sprayed on the base silica. Depending on the method. Alternatively, it may be prepared by dissolving or dispersing a silicone oil in an appropriate solvent, mixing with a base silica fine powder, and removing the solvent.

Any appropriate pigment or dye can be used as a colorant in the toner. For example, there are known dyes and pigments such as carbon black, iron black, phthalocyanine blue, ultramarine, quinacridone, and benzidine yellow.

When the toner is a magnetic toner, iron,
Ferromagnetic elements such as cobalt and nickel, or alloys and compounds such as iron, cobalt, nickel and manganese such as magnetite, hematite and ferrite, and magnetic materials such as other ferromagnetic alloys may be contained.

Additives may be added to the toner as needed. Examples of such additives include lubricants such as Teflon and zinc stearate, fixing aids (eg, low molecular weight polyethylene), and metal oxides such as tin oxide as a conductivity-imparting agent.

[0102]

Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on embodiments. However, this does not limit the embodiment of the present invention at all. Parts in the examples are parts by weight.

(Resin Synthesis Example 1) Xylene 20 was placed in a reaction vessel.
0 parts were added and the temperature was raised to the reflux temperature. Styrene 85
Parts, 15 parts of butyl acrylate, and 2 parts of di-tert-butyl peroxide were mixed, and the solution polymerization was completed in 6 hours under reflux of xylene to obtain a low molecular weight resin solution.

On the other hand, 70 parts of styrene, 25 parts of butyl acrylate, 5 parts of monobutyl maleate, 0.003 parts of divinylbenzene, 0.1 part of polyvinyl alcohol, 200 parts of degassed water, 2,2-bis (4,4 -Di-tert-butylperoxycyclohexyl) propane (0.1 part) was mixed, suspended and dispersed. The above suspension and dispersion solution was heated and maintained at 85 ° C. for 24 hours under a nitrogen atmosphere. Then, 0.1 part of benzoyl peroxide was additionally added, and further maintained for 12 hours to complete the polymerization to obtain a high molecular weight resin. Was. Next, the resin was washed with an aqueous solution of NaOH equivalent to 4 times the acid value of the resin for 2 hours.

25 parts of this high-molecular-weight resin and 4 parts of low-molecular-weight polypropylene are put into a solution at the time of completion of solution polymerization of 75 parts of the above-mentioned low-molecular-weight resin, completely dissolved in a solvent and mixed, and then the solvent is distilled off. Then, a styrene-butyl acrylate-monobutyl maleate copolymer composition having the following characteristics was obtained.

Low molecular side molecular weight peak P ₁ = 10,400 (main peak) High molecular side molecular weight peak P ₂ = 1,200,000 (sub peak) Weight average molecular weight Mw = 340,000 Number average molecular weight Mn = 6000 Mw / Mn = about 56 .67

(Resin Synthesis Example 2) A styrene-acrylic resin having the following characteristics was prepared in the same manner as in Synthesis Example 1 except that the mixing ratio of the high molecular weight resin and the low molecular weight resin in Synthesis Example 1 was changed to 40 parts and 60 parts, respectively. A butyl acrylate-monobutyl maleate copolymer composition was obtained.

Low molecular side molecular weight peak P ₁ = 10,400 (main peak) High molecular side molecular weight peak P ₂ = 1,200,000 (sub peak) Weight average molecular weight Mw = 420,000 Number average molecular weight Mn = 7100 Mw / Mn = about 59 .15

Example 1 100 parts of the resin composition of Resin Synthesis Example 1 100 parts of a magnetic fine powder 0.6 part of a negative charge control agent (monoazo dye-based chromium complex)

The above mixture was melted and kneaded with a twin-screw extruder heated to 130 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill. Was classified by wind power, and the volume average particle size was 6.
8 μm magnetic particle classification powder-1 was obtained.

Silicic acid fine powder DM-30S treated with dichlorodimethylsilane (specific surface area 235, manufactured by Tokuyama Soda Co., Ltd.)
m ² / g) 100 parts of methyl hydrogen silicone oil KF-99 (Shin-Etsu Chemical Co., Ltd. viscosity 20cSt
(25 ° C.) 15 parts were diluted with a solvent, treated, dried, and heated at 190 ° C. to obtain a treated fine silica powder. 0.9 parts of this treated silicic acid fine powder was added to 100 parts of the magnetic particle classified powder-1 and dry-mixed with a Henschel mixer to prepare a developer.

This developer was subjected to an image-drawing test using a commercially available laser beam printer LBP LX modified as follows.

An electrostatic latent image is formed by setting the primary charge to -600 V, a gap (300 μm) is set without contact between the photosensitive drum and the developer layer on the developer carrier (magnet inclusion), and an AC bias (f = 1800 Hz, V _PP = 1200 V) and a DC bias (V _DC = −400 V).

Under the above setting conditions, an image forming test for forming a developer image by a reversal developing method over 3000 sheets continuously at a printing speed of 4 sheets (A4) / min was conducted at normal temperature and normal humidity (25 ° C./6
0% RH), and the obtained images were evaluated for the following items. At the same time, the state of the surface of the photosensitive drum was observed to evaluate its durability. The evaluation results are summarized in Table 1.

<Evaluation Items> (1) Image Density The image density was evaluated by maintaining the image density at the end of printing out 3000 sheets of ordinary paper for copying machines (75 g / m ² ).

◎ (excellent): 1.40 or more
(Good): 1.40 to 1.35 △ (acceptable): 1.35 to 1.00 × (impossible):
Less than 1.00

The image density was measured using a Macbeth reflection densitometer (manufactured by Macbeth).

(2) Image Quality (Dropout) The degree of dropout in the printout image was visually evaluated.

◎: very good, ：: good Δ: practical, ×: impractical

(3) Fusing Condition on Photoconductor Drum After the printout test, the fusing condition of the developer on the photoconductor drum was visually evaluated.

◎: very good (not generated), ：: good (almost no occurrence) Δ: practical, ×: impractical

As a result, even after printing out 3000 sheets, both the image density and the omission in the image were good, and no fixation or fusion of the developer occurred on the photosensitive drum at all.

Example 2 The same mother silica fine powder as in Example 1 was prepared using a silicone oil KF-96 (manufactured by Shin-Etsu Chemical Co., Ltd., viscosity: 100%) containing 50% by weight of methyl hydrogen silicone oil KF-99.
A treated silica fine powder was obtained by the same treatment as in Example 1 using a silicone oil mixed with cSt (25 ° C.).
This treated silicic acid fine powder was used as the magnetic particle classified powder-1 of Example 1.
1.2 parts was added to 100 parts, and dry-mixed with a Henschel mixer to prepare a developer.

This developer was evaluated in the same manner as in Example 1.
Table 1 shows the evaluation results.

As a result, even after the printout of 3000 sheets, both the image density and the omission in the image were good, and no fixation or fusion of the developer on the photoreceptor occurred at all.

Example 3 Example 1 was repeated except that the resin composition of Resin Synthesis Example 2 was used.
In the same manner as in the above, the mixture was melt-kneaded, cooled, pulverized, finely pulverized, and air-classified to obtain magnetic particle classified powder-2 having a volume average particle size of 6.8 μm.

In the same manner as in Example 1, the mixture was treated with a silicone oil mixed with a silicone oil KF-96 (100 cSt (25 ° C.)) containing 10% by weight of methyl hydrogen silicone oil KF-99 to obtain a treated silica fine powder. Was. This treated silicic acid fine powder was mixed with the above-mentioned magnetic particle classified powder-2.
0.9 part was added to 100 parts, and dry-mixed with a Henschel mixer to prepare a developer.

This developer was evaluated in the same manner as in Examples 1 and 2. Table 1 shows the evaluation results.

As a result, even after printing out 3000 sheets, both the image density and the omission of the image were good.
Adhesion and fusion of the developer on the photoreceptor hardly occurred.

[0130] without silicone oil treatment similar parent silica fine powder as in Comparative Example 1, 0.9 parts added to it the magnetic particle classification powder -1 100 parts, were dry mixed in a Henschel mixer, development An agent was prepared.

The developer was evaluated in the same manner as in Example 1.
Table 1 shows the evaluation results.

As a result, after printing out 3,000 sheets, the image density was lowered and the image missing was remarkably generated. Further, the developer is fixed on the photoreceptor, and an image defect caused by the developer has occurred.

[0133]

[Table 1]

[0134]

According to the developing method of the present invention, it is possible to always obtain a high-density and good image without a hollow portion, and it is possible to obtain an image defect due to the fusion of the developer to the photosensitive drum. Generation can be prevented.

──────────────────────────────────────────────────続 き Continuing on the front page (72) The inventor, Manabu Ohno 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) The inventor Akihiko Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-59-231550 (JP, A) JP-A-4-214568 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08 -9/087

Claims (1)

(57) [Claims] 1. An electrostatic latent image formed on a photosensitive drum.
The photosensitive drum and the developer layer on the developer carrier are not in contact with each other.
Set the interval so that
Developing method of applying ias to the developer carrier to develop
In the above, the developer for forming the developer layer comprises a binder resin and a developer.
With toner particles containing colorant and silane coupling agent
After the treatment, the methyl hydrogen silicone
Oil or methyl hydrogen silicone
Oil or silicone oil containing 10% by weight or more
Mixing with fine silica powder treated with corn varnish mixture
The binder resin is prepared by using (a) a vinyl monomer to obtain a solution weight.
A low molecular weight resin synthesized by a legal method, and (b) a vinyl resin
100 parts by weight of monomer and 0.001-crosslinkable monomer
0.01 parts by weight of polyfunctional initiator and monofunctional initiator
And the high molecular weight resin synthesized by the suspension polymerization method.
Solution in the presence of an agent, then remove the solvent
And a gel permeation chromatography of the binder resin.
Has a molecular weight of 2,000.
It has a main peak in the region of ~ 30,000 and a molecular weight of 1
Sub-peaks or shoulders in more than 100,000 polymer regions, weight
Average molecular weight (Mw) / number average molecular weight (Mn) is 30 or more
A developing method, characterized in that: