JPH0572804A - Dry toner, developer and image forming method - Google Patents

Abstract

PURPOSE:To obtain a dry toner with which long-life high-precision images can be obtd. and high-density images can be obtd. for a long time by incorporating a specified styrene-acryl resin and metal salt of benzilic acid deriv. into the toner. CONSTITUTION:The toner contains a styrene-acryl resin having 10-50wt.% gel content and a metal salt of benzilic acid deriv. expressed by formula I (wherein M is alkali metal) as a charge controlling agent. Thus, a styrene-acryl resin such as styrene-acrylate copolymer, styrene-methacrylate copolymer, etc., having 10-50wt.% gel content is used as the binder resin. The monomer for the styrene- acryl resin has one vinyl group in one molecule, for example, styrene, styrene deriv, methacrylate, acrylate, etc. It is preferable that a metal salt of benzilic acid deriv. is incorporated into the toner by 0.1-5wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry toner useful for developing an electrostatic image formed in electrophotography, a developer and an image forming method using the dry toner.

[0002]

2. Description of the Related Art In electrophotography, after uniformly charging a photoconductor, a photoimage based on an original image is exposed to the photoconductor to eliminate or reduce the electric charge in a light-irradiated portion, An electrostatic latent image based on the original image is formed on the top, and after that,
It is well known that a so-called two-component developer, which is composed of carrier particles and toner particles, is used to obtain a visualized copy. In this two-component developer, fine toner particles are held on the surface of a relatively large carrier particle by the electrostatic force generated by the friction between the particles, and when the electrostatic latent image is approached, the electrostatic latent image is generated. The attraction force of the electric field formed by the toner particles in the direction of the latent image against the toner particles overcomes the binding force between the toner particles and the carrier particles, and the toner particles are attracted and adhered to the electrostatic latent image to form the electrostatic latent image. It is what is visualized. Then, the developer is repeatedly used while replenishing the toner consumed by the development.

Further, in recent years, S has been used as a photoreceptor for an electrostatic image.
Photoconductors having organic photoconductive layers in place of inorganic photoconductive layers such as e, Se-Te, As ₂ Se ₃ (hereinafter referred to as organic photoconductors) have been used in copying machines and printers. The organic photoconductor has a lower surface hardness than the inorganic photoconductor, and is more likely to be damaged or rubbed by a developer, especially a carrier.

The function of the conventional laser beam printer using the electrophotographic method is to output a line image of alphabets, numbers, kanji, or the like. In recent years, in addition to line images, the need to output surface images such as barcodes and solid black has increased. In surface image printing such as bar code printing, the electric flux density at the central portion of the latent image pattern formed on the surface of the photoconductor drum is much lower than that at the edge portion. Therefore, during the developing process, the toner is concentrated on the edge portion of the pattern and hardly adheres to the central portion of the pattern, which is a defect in the printing process.

Recently, a digital type copying machine has been developed, and the demand for high-definition image output of the copying machine, laser beam printer, etc. has become stronger. For example, until now, most printers have 240 dpi or 300
Although it was dpi, it will be 480 dpi in the future and 6
It is expected that high-definition image output of 00 dpi will become the mainstream.

[0006]

In order to solve these drawbacks and output a surface image, a bias voltage is applied,
A method for controlling printing has been proposed. This bias voltage is a static voltage applied between the surface of the photoconductor drum and the magnetic brush so that the magnetic brush side has a polarity opposite to that of the voltage of the toner. The bias voltage causes the toner particles to move to a portion of the surface of the photosensitive drum having a low electric flux density, and as a result, a uniform surface image can be obtained. However, when the bias voltage is very strong, the toner may adhere to a portion other than the latent image formed on the photosensitive drum, and a phenomenon called so-called fog may occur.

The bias voltage method as described above is particularly effective in the case of a developer using a carrier having a low electric resistance. When a carrier having a high electric resistance is used, the voltage drop at the magnetic brush portion is large and the voltage difference between the magnetic brush tip and the surface of the photoconductor is low, so that an effective bias voltage application effect cannot be obtained. When a carrier having an extremely low electric resistance is used, the voltage drop in the magnetic brush portion is small and it is preferable in terms of the bias voltage effect, but it is not preferable from the standpoint of chargeability with the toner, that is, charge imparting to the toner.

When the developer is used for a certain period of time, a phenomenon called so-called spent, in which the toner is fused to the surface of the carrier, occurs, resulting in an increase in the resistance of the carrier. As a method of reducing the spent amount, a method of coating a material on which the toner is hard to adhere to the carrier surface, for example, a fluororesin, a polybutadiene resin, a silicone resin, etc. is adopted, but the electric resistance of the coating material itself is high, Is not suitable for low resistance.

On the other hand, in order to improve the quality of line drawing printing and the output of surface printing, a method of using a carrier having a large specific surface area to increase the toner concentration in the developer is also being studied.
However, in this method, there are problems such as toner scattering and carrier adhesion to the photoconductor.
Further, it is difficult to maintain the print quality of the plane image for a long time.

Further, in order to support high-definition image output,
It may be possible to reduce the toner particle size or the carrier particle size.
For example, there are problems such as crushing efficiency and classification accuracy, and in terms of characteristics, there are problems such as fluidity, charging uniformity, toner scattering, developer deterioration, cleaning properties, transfer properties, and fixing properties.
In addition, when the particle size of the carrier is reduced, there is a problem that the carrier adheres to the surface of the photoreceptor.

Further, due to the recent cost increase caused by the soaring price of oil, it has been studied to use a common toner, that is, to use the same toner from low-speed machines to medium-high speed machines. This requires the toner to have better fixability and wider offset resistance.

Therefore, various binder resins for toner have been studied. It is generally known that when a resin containing a gel component is used as a binder resin, it has excellent offset resistance, particularly high temperature offset resistance. However, a resin having a gel content is difficult to melt-knead, and dispersion of pigments such as carbon black and various additives is insufficient, and thus the obtained dry toner is inferior in characteristics such as fog and resolution. This tendency is particularly large when a toner having a small particle diameter is used.

The present invention solves these problems and provides a dry toner, a developer and an image forming method capable of obtaining a high-definition image with a long life and capable of outputting a high-density surface image for a long time. Is.

[0014]

The present invention has a gel content of 10 to 10.
Styrene-acrylic resin containing 50% by weight and formula (I) as a charge control agent

[Chemical 2] A dry toner containing a metal salt of a benzylic acid derivative (where M is an alkali metal), a developer containing the dry toner and a carrier, and an image formation using the developer Regarding the method.

The dry toner of the present invention contains, as a binder resin,
It is important to use a styrene-acrylic resin such as a styrene-acrylic acid ester copolymer or a styrene-methacrylic acid ester copolymer having a gel content of 10 to 50% by weight.

The following monomers can be given as examples of the base monomer of the styrene-acrylic resin. Styrene and its derivatives such as styrene, α-methylstyrene, p-methylstyrene, p-t-butylstyrene, p-chlorostyrene, and hydroxystyrene, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid. Butyl, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, methacrylic acid Butoxyethyl, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxide Ethylene glycol, methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, Dicyclopentenyloxyethyl methacrylate, N-vinyl-2-pyrrolidone methacrylate, methacrylonitrile, methacrylamite, N
-Methylol methacrylamide, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, 2-hydroxy-3-phenyloxypropyl methacrylate, phthalimidoethyl methacrylate, phthalimidopropyl methacrylate, morpholinoethyl methacrylate, methacryl Acid morpholinopropyl, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, diacetone methacrylamide, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, butyl acrylate ,
Octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate,
Methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, benzyl acrylate , Cyclohexyl acrylate, tetrahydrofurfuryl acrylate,
Dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, N-vinyl-2-pyrrolidone acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate ,
Glycidyl acrylate, acrylonitrile, acrylamide, N-methylol acrylamide, diacetone acrylamide, vinyl pyridine, phthalimidoethyl acrylate, phthalimidopropyl acrylate, morpholinoethyl acrylate, morpholinopropyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate Reaction products of divinylbenzene, glycol with methacrylic acid or acrylic acid, such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate , Triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythriate Trit tetramethacrylate, tris methacryloyloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris (methacryloyloxyethyl) isocyanurate, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butane Diol diacrylate,
1,5-Pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene diacrylate, hydroxypiparinate neo Pentyl glycol diacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris (methacryloyl) Oxyethyl) isocyanurate, glycidyl methacrylate and methacrylic acid Other half-esters of acrylic acid, bisphenol type epoxy resin and half-esters of methacrylic acid or acrylic acid, half ester of glycidyl acrylate with methacrylic acid or acrylic acid. Among these monomers, preferable ones having one vinyl group in one molecule include styrene, styrene derivatives, methacrylic acid esters and acrylic acid esters.

As the polymerization initiator used in the polymerization, acetyl peroxide, decynol peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and perdicarbonic acid are used. Diisopropyl, di-2-ethyl-hexyl perdicarbonate, acetylcyclohexanesulfonyl peroxide, peracetic acid t
ert-butyl, tert-butyl perisobutyrate, azobisisobutyronitrile, 2,2'-azobis-2,4-
Dimethylvaleronitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, tert-butyl per-2-ethylhexanoate, tert-perbenzoic acid
A known polymerization initiator such as butyl is used. These are preferably used in an amount of 0.1 to 15% by weight based on the total amount of monomers.

The styrene-acrylic resin having a gel content of 10 to 50% by weight can be produced by a suspension polymerization method using water as a dispersion medium, an emulsion polymerization method or the like. Suspension polymerization is preferred because post-treatment such as resin drying is easy. The gel content is adjusted by the polyfunctional monomer that is copolymerized. As the polyfunctional monomer, the above-mentioned divinylbenzene,
Although ethylene glycol diacrylate, trimethylolpropane triacrylate, etc. can be used, it is preferable to use divinylbenzene because of its copolymerizability and the like. In the suspension polymerization method, the gel content can be adjusted by dividing the polymerization process. For example, suspension polymerization is performed using a copolymerizable monomer mixture containing no polyfunctional monomer in the first stage, and then a copolymerizable monomer mixture containing a polyfunctional monomer is added in the second stage to complete the polymerization. To do. This method is a preferable method because the gel content can be controlled easily and freely to some extent.

When the gel content of the styrene-acrylic resin is less than 10% by weight, the wide offset resistance of the present invention cannot be obtained. If the gel content exceeds 50% by weight, good fixability cannot be obtained. Further, melt-kneading becomes difficult, and a large amount of energy is required. A particularly preferable range of gel content is 2 from the viewpoint of offset resistance and fixability.
It is 0 to 40% by weight. The gel content in the present invention is measured using a Soxhlet extractor with methyl ethyl ketone as the solvent.

In the toner of the present invention, the above styrene-
Acrylic resin is used as the balance of additives such as colorants and charge control agents, but is usually 45 to 95 with respect to all toner components.
It is contained by weight%. A binder resin other than the styrene-acrylic resin may be used in combination as long as the effect of the present invention is not impaired.

The metal salt of the benzylic acid derivative used as the charge control agent in the present invention has the formula (I)

[Chemical 3] (Where M is an alkali metal such as Li, Na or K). A particularly preferable metal salt is a potassium salt from the viewpoint of charge stability. The dry toner of the present invention comprises the styrene-
By using this metal salt of a benzylic acid derivative together with an acrylic resin, even if the amount of charge is low, there is almost no toner scattering, and in particular, the charging stability is excellent and a high-density image can be obtained for a long time. It has characteristics such as being

The amount of the metal salt of the benzylic acid derivative used is preferably 0.1 to 5% by weight based on the total toner components. 0.
If it is less than 1% by weight, it is difficult to obtain sufficient chargeability.
The charge stability tends to be poor, and toner scattering is likely to occur. On the other hand, when the amount of the metal salt of the benzylic acid derivative exceeds 5% by weight, it is difficult to obtain a high density image. A particularly preferable amount of the metal salt of the benzylic acid derivative is 1 to 3% by weight.

A colorant is usually used in the toner of the present invention. As the colorant, carbon black, nigrosine dye, acetylene black, aniline black, cyanine black, black colorants such as graphite, iron black, yellow lead, cadmium yellow, yellow iron oxide, titanium yellow, chromium yellow, naphthol yellow, hansa yellow, Pigment Yellow, Benzidine Yellow, Permanent Yellow, Quinoline Yellow Lake, Anthracyrimidine Yellow, etc.Yellow Colorants, Permanent Orange, Molybdenum Orange, Balkan Hurst Orange, Benzene Orange, Indanthrene Brilliant Orange, etc.Orange Colorants, Iron Oxide, Amber, brown colorants such as permanent brown, red iron oxide,
Rose Bengal, Antimony powder, Permanent red,
Red colorants such as fire red, brilliant kamine, light astored toner, permanent carmine, pyrazolone red, bordeaux, helio-bordeaux, rhodamine lake, deyupon oil red, thioindigo red, thio indigo maroon, watering red strontium. , Cobalt purple, Farst violet, Dioxazine violet, Methyl violet, and other purple colorants, Methylene blue, Aniline blue, Cobalt blue, Cerulean blue, Calco oil blue, Metal-free phthalocyanine blue, Phthalocyanine blue, Ultramarine blue , Blue colorants such as indanthrene blue, indigo, chrome green, cobalt green, pigment green B, green gold, phthalocyanine green Malachite green oxalate, pigments or dyes such as a green coloring agent such as a poly chromium brominated copper phthalocyanine, titanium oxide, there is a metal oxide powder such as zinc oxide, it is preferable to use carbon black in these. These colorants are added to the toner in 2
˜15 wt%, more preferably 4 to 12 wt%, especially 6 to 12 wt%. If it is less than 2% by weight, the print density tends to vary due to insufficient coloring power or unstable charging. On the other hand, when the amount exceeds 15% by weight, the adhesive force to the toner image support becomes insufficient, and the toner tends to scatter due to an insufficient amount of charge.

If desired, a known charge control agent other than those represented by the above formula (I) may be used in combination with the toner of the present invention. Examples of such charge control agents include azo compound metal complexes, oxycarboxylic acid metal complexes, nigrosine dyes, fatty acid-modified nigrosine dyes, resin acid-modified nigrosine dyes, and quaternary ammonium salts. These are preferably added in an amount of 0.1 to 3% by weight based on all toner components.
Furthermore, it is preferable to use the same amount as the metal salt of the benzylic acid derivative, particularly, a smaller amount.

The toner of the present invention may further contain other additives, if necessary. Such other additives include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, 3-methyl-1-butene, 3-methyl-2-pentene, 3-propyl-5-. Polymers of olefin monomers such as methyl-2-hexene or copolymers of the above olefin monomers with acrylic acid, methacrylic acid, vinyl acetate, etc., lower alcohol esters of fatty acids such as butyl stearate, propyl stearate, Polyester of fatty acid such as casta wax (made by Ito Oil Co., Ltd.), diamond wax (made by Shin Nippon Rika Co., Ltd.), palm aceti (made by NOF Corporation), Hoechst Wax E, Hoechstwa Fatty acids such as Tux-OP (manufactured by Hext Actien Gezershyaft) and Karnaubawax Higher alcohol ester, Bisamide blast flow (manufactured by Nitto Chemical Co., Ltd.), Amide 6L, 7S and 6H (manufactured by Kawaken Huain Chemical Co., Ltd.), Hoechst Wax C (Hoechst, Actien Gelsyaft) Nitpol NB, an alkylene bis fatty acid amide compound
R, 2057S, 2007JBR1220 and the like include diene resins having a weight average molecular weight of 50,000 or more, hydroxyl group-containing vinyl resins, carboxyl group-containing vinyl resins and the like.
These other additives play a role of preventing damage to the photoconductor during cleaning of the non-transfer toner, and the amount of 0.1 to 0.1 is contained in the toner.
It is preferable to add 20% by weight, particularly 1 to 10% by weight.

The dry toner of the present invention can be manufactured by a usual method. For example, styrene with a gel content of 10 to 50% by weight
Acrylic resin, as a charge control agent, metal salts of benzylic acid derivatives and colorants such as carbon black, dyes, pigments such as magnetite, and in some cases, nigrosine dyes, azo dyes, salicylic acid derivatives and metal salts of sols The above charge control agent and various other additives such as fixing property improvers such as polypropylene, polyethylene and carnauba wax are mixed and mixed in a commonly used amount, and well melt-kneaded with a mixer such as a hot roll mill or a co-kneader. To do. The kneaded product obtained above can be cooled, pulverized and classified by a usual method to obtain a dry toner. In addition to these toners, hydrophobic silica, alumina, molybdenum disulfide,
A fluidity improver such as titanium oxide and a cleaning improver such as zinc stearate, magnesium stearate and zinc laurate may be externally added and used.

The dry toner of the present invention has excellent fluidity of the toner, is less likely to contaminate the carrier, and can provide a long-life developer. The average particle size of the toner used in the present invention is preferably 5 to 12 μm, particularly preferably 6 to 10 μm. When the average particle size of the toner is less than 5 μm, the resolution is excellent, but the fluidity of the toner tends to be poor, and it is difficult to supply the toner from the toner hopper to the developer, or the fluidity of the developer is deteriorated. There is a problem, and toner scattering and fog may occur. On the other hand, when the average particle size exceeds 12 μm, the resolution tends to be poor. In recent years, it has been important to control the particle size of toner for high-definition images. In particular, when outputting a high definition image of 600 dpi or more, it is necessary to reduce the toner particle size. 60
The preferred particle size range for 0 dpi is 6-8 μm.

The particle size of the toner can be measured by a usual method, but if the amount of the sample is small, the measurement time is short, the repeatability is excellent, etc., the particle size is measured by using a Coulter Counter (manufactured by Coulter Co.). good.

The dry toner thus obtained is mixed with a carrier to obtain the developer of the present invention. The toner concentration in the developer may be a normal amount (1 to 10% by weight based on the total amount of the developer).

As the carrier used in the present invention, a ferrite carrier having a particle size of 30 to 300 μm, such as iron ferrite, copper zinc ferrite, nickel zinc ferrite, etc., is preferably used. If the average particle size of the carrier is less than 30 μm, the carrier tends to adhere to the surface of the photoconductor, causing damage to the photoconductor and deterioration of image quality. On the other hand, if the average particle size exceeds 300 μm, the amount of toner that can be held on the carrier surface decreases, and the quality of images tends to fluctuate during continuous printing. Also,
In particular, when an organic photoreceptor is used as the electrostatic image photoreceptor, it is preferable to use a ferrite carrier because damage to the photoreceptor is small.

The carrier used in the present invention is particularly preferably coated with a resin. Examples of the coating resin include styrene-acrylic resin, silicone resin, fluorine-containing resin, polyester resin, modified amino resin, and the like, and these can be used alone or in combination of two or more. Further, depending on the case, various additives, such as carbon black, a charge control substance such as a nigrosine derivative, alumina, silica, etc., may be added to various resins. As a coating resin,
In particular, a silicone resin or a modified silicone resin is preferable because a high-concentration image can be obtained. Ferrite type carrier is coated with resin, so that it can be charged
Moisture resistance and durability are greatly improved. A particularly preferred carrier to be combined with the dry toner of the present invention is a ferritic carrier coated with a silicone resin or a modified silicone resin.

As a coating method, various resins are dissolved in an organic solvent such as toluene, dichloromethane, dichloroethane, or tetrahydrofuran, and the carrier is dipped in the solution, or the solution is sprayed on the carrier and dried. The drying temperature is preferably 120 to 200 ° C.

Further, in order to form a sufficient coating film and obtain uniform chargeability, moisture resistance and durability, the concentration of the coating resin solution is preferably 3 to 30% by weight. In order to obtain the above characteristics, the thickness of the coating layer is preferably about 0.1-5 μm.

Here, the charge amount of the toner in the developer is -5 with a blow-off charge amount measuring device (manufactured by Toshiba Chemical Co.).
It is preferably −40 μc / g, particularly preferably −10 to −30 μc / g. If the blow-off charge amount is less than −5 μc / g, toner may scatter or the image may be extremely fogged when the developer is stirred. Also, -40 μc
If it exceeds / g, the image density becomes extremely low.

The developer of the present invention can be used in various development processes,
For example, the cascade developing method described in U.S. Pat. No. 2,618,552, the magnetic brush method described in U.S. Pat. No. 2,870,405, and U.S. Pat. No. 222.
It can be used for the powder cloud method described in US Pat. No. 17,761, and the touch-down developing method described in US Pat. No. 3,166,432.

The developer of the present invention can be used in various fixing methods such as so-called oilless and oil coating heat roll method, flash method, oven method and pressure fixing method. Further, the developer of the present invention can be used in various cleaning methods such as so-called fur brush method and blade method.

The developer of the present invention is used in an image forming method in which an electrostatic latent image formed on a photoconductor is brought into contact with the latent image to be visualized, transferred to a support and fixed. In particular, it can be effectively applied to an image forming method in combination with a photoconductor made of an organic photoconductive substance.

The photosensitive member is preferably a function-separated type in which the charge-generating layer and the charge-transporting layer which are excellent in sensitivity are different from each other. Generally, in the charge generation layer, azoxybenzene-based, disazo-based, trisazo-based, benzimidazole-based, polycyclic quinoline-based, indigoid-based, quinacridone-based, phthalocyanine-based, perylene-based, methine-based pigments are known. (JP-A-47-37543, JP-A-47-37544)
JP-A-47-18543, JP-A-47-1854
4, JP-A-48-43942, JP-A-48-705.
38, JP-A-49-1231, JP-A-49-105.
536, JP-A-50-75214, and JP-A-50-
Any of these can be applied, but phthalocyanine-based pigments are particularly preferable from the viewpoint of charge generation efficiency. Further, the charge carrying layer contains a pyrazoline derivative (Journal of Photographic).
Science and Engineering, Volume 21, No. 2, p. 73, 1977), oxazole derivatives (JP-A-55-35319, JP-A-58-87).
557 and JP-A-58-182640) Hydrazone derivatives (JP-A-54-59143 and JP-A-54).
-150128, and JP-A-55-46760), enamine derivatives (Journal of Ima)
gingScience, Vol. 29, No. 1, p. 7, 1
985), butadiene derivatives and the like are known and used.

Further, as the binder resin for fixing these organic photoconductive substances to the supporting member of the photoreceptor, polycarbonate resin, esterified polycarbonate resin, silicone resin, styrene resin, styrene-acrylic resin, polyamide resin, polyester resin , Polyvinyl butyral resin, etc. are used. In the image forming method of the present invention, the magnetic brush method is preferably used as the developing method and the hot roll method is preferably used as the fixing method, but the invention is not limited thereto.

[0040]

EXAMPLES The present invention will now be described with reference to examples, but the present invention is not limited thereto. "%" In the examples
Means “% by weight” unless otherwise specified. Resin Synthesis Example 1 In a four-neck separable flask equipped with a stirrer, nitrogen inlet, thermometer and condenser, ion-exchanged water 200 g, tricalcium phosphate 10% aqueous solution (Super Tight 10
10 g of Nippon Kagaku Co., Ltd. was added, and then 50 g of styrene, 20 g of butyl methacrylate and 3 g of benzoyl peroxide were added thereto, and polymerization was carried out at 85 ° C. for 4 hours. Then, the mixture was cooled to 40 ° C., 20 g of styrene, 10 g of butyl methacrylate, 0.15 of civinylbenzene.
g, 1,1-bis (t-butylperoxy) 3,3,5
-Trimethylcyclohexane (Perhexa 3M, manufactured by NOF CORPORATION) was added, and the mixture was stirred at 50 ° C for 1 hour, and then polymerized at 80 ° C for 4 hours and 90 ° C for 4 hours. The obtained resin (designated as styrene-acrylic resin 1) was dried, and the gel content was measured with a Soxhlet extractor using methyl ethyl ketone as a solvent, and it was 28%.

Resin Synthesis Example 2 In the same manner as in Synthesis Example 1, 60 g of styrene and 25 g of butyl methacrylate were polymerized with 3 g of benzoyl peroxide in the first stage, and then 10 g of styrene, 5 g of butyl methacrylate and divinylbenzene in the second stage. 0.06g
Was polymerized with 0.5 g of Perhexa 3M. The resin thus obtained (styrene-acrylic resin 2) was dried and the gel content was measured and found to be 15%.

Synthetic Example 3 of Resin In the same manner as in Synthetic Example 1, 35 g of styrene and 15 g of butyl methacrylate were polymerized with 2.5 g of benzoyl peroxide in the first stage, and then styrene 35 in the second stage.
g, 15 g of butyl methacrylate and 0.2 g of divinylbenzene were polymerized with 1 g of Perhexa 3M. The obtained resin (designated as styrene-acrylic resin 3) is dried,
The gel content was measured and found to be 48%.

Resin Synthesis Example 4 Using the same apparatus as in Synthesis Example 1, ion-exchanged water 200
g, Supertite 1010 g, styrene 70 g, butyl methacrylate 30 g, divinylbenzene 0.02
g and benzoyl peroxide 3 g were added, and the mixture was polymerized at 80 ° C. for 4 hours and 90 ° C. for 4 hours. The resin obtained (designated as styrene-acrylic resin 4) was dried and the gel content was measured and found to be 32%.

Resin Synthesis Example 5 Using the same apparatus as in Synthesis Example 1, ion-exchanged water 200
g, Supertite 1010 g, styrene 70 g, butyl methacrylate 30 g, divinylbenzene 0.1
g and benzoyl peroxide 3 g were added, and polymerization was carried out at 80 ° C. for 4 hours and at 90 ° C. for 4 hours. The obtained resin (designated as styrene-acrylic resin 5) was dried and the gel content was measured and found to be 58%.

Resin Synthesis Example 6 Using the same apparatus as in Synthesis Example 1, ion-exchanged water 200
g, Supertite 1010 g, styrene 70 g, butyl methacrylate 30 g, and benzoyl peroxide 3 g were added, and polymerization was carried out at 80 ° C. for 4 hours and at 90 ° C. for 4 hours. The obtained resin (styrene-acrylic resin 6)
Was dried and the gel content was measured, but there was no gel content.

Resin Synthesis Example 7 Using the same apparatus as in Synthesis Example 1, ion-exchanged water 200
g, Supertite 1010 g, styrene 70 g, butyl methacrylate 30 g, divinylbenzene 1 g, and benzoyl peroxide 3 g were added, and polymerization was carried out at 80 ° C. for 4 hours and at 90 ° C. for 4 hours. The resin obtained (designated as styrene-acrylic resin 7) was dried and the gel content was measured and found to be 95%.

Example 1 Carbon black (# 44, manufactured by Mitsubishi Kasei Co., Ltd.) was added to 85 parts by weight of styrene-acrylic resin 1 prepared in Synthesis Example 1.
10 parts by weight, potassium salt of a benzylic acid derivative (NR-147, manufactured by Nippon Carlit Co., Ltd.), 3 parts by weight, low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
Styrene-acrylic toner I was prepared. The particle size of this toner measured with a Coulter Counter (manufactured by Coulter, Inc.) was 5 to 20 μm, and the average particle size was 9 μm.
In addition, the subsequent particle size was also measured with a Coulter counter.

Manufacture of Developer A coating carrier (particle size 60) in which the prepared styrene-acrylic toner I was coated with a ferrite carrier as a carrier and an acrylic-modified silicone resin
˜100 μm, average particle size 90 μm) were mixed so that the toner / carrier was 4/96 (weight ratio), and mixed with a V-type blender to prepare a developer I. As a result of measuring a blow-off charge amount (manufactured by Toshiba Chemical Co., Ltd., blow-off powder charge amount measuring device), it was -16 μc / g.

Example 2 85 parts by weight of styrene-acrylic resin 2 produced in Synthesis Example 2, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight, potassium salt of a benzylic acid derivative (NR-147, manufactured by Nippon Carlit Co., Ltd.), 3 parts by weight, low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
A styrene-acrylic toner II was prepared. The particle size of this toner measured with a coulter counter is 4 to 15
The average particle size was 6 μm.

Manufacture of Developer A coating carrier (particle size 60 to 100 μm average particle size 90 μm) in which a ferrite carrier is coated with an acrylic modified silicone resin on the prepared styrene-acrylic toner II has a toner / carrier ratio of 4/96 (weight ratio). ) And mixed with a V-type blender to prepare a developer II. Blow-off charge of developer is -20
It was μc / g.

Example 3 85 parts by weight of styrene-acrylic resin 3 produced in Synthesis Example 3, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight, potassium salt of a benzylic acid derivative (NR-147, manufactured by Nippon Carlit Co., Ltd.), 3 parts by weight, low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
Styrene-acrylic toner III was prepared. The particle size of this toner measured with a coulter counter is 4 to 1
The average particle size was 5 μm and 6 μm.

Manufacture of Developer A coating carrier (particle diameter 60 to 100 μm average particle diameter 90 μm) prepared by coating the styrene-acrylic toner III prepared above with a ferrite carrier with an acrylic modified silicone resin was used in a toner / carrier ratio of 4/96 (weight). Ratio), mix with a V-type blender,
Developer III was prepared. Blow-off charge of developer is −
It was 18 μc / g.

Example 4 85 parts by weight of styrene-acrylic resin 4 produced in Synthesis Example 4, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight 3 parts by weight of potassium salt of benzylic acid derivative (LR-147, manufactured by Nippon Carlit Co., Ltd.), low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight, and kneaded with a kneader PCM-30. Then, styrene-acrylic toner IV was prepared through coarse pulverization with a hammer mill, fine pulverization with a jet mill, and classification with a zigzag classifier. The particle size of this toner measured with a coulter counter is 4 to
The average particle size was 15 μm and the average particle size was 6 μm.

Production of Developer A coating carrier (particle diameter 60 to 100 μm average particle diameter 90 μm) prepared by coating a ferrite carrier with an acrylic modified silicone resin on the prepared styrene-acrylic toner IV has a toner / carrier ratio of 4/96 (weight). Ratio) and mixed with a V-type blender to prepare a developer IV. Blow-off charge of developer is -17
It was μc / g.

Example 5 87 parts by weight of styrene-acrylic resin produced in Synthesis Example 1 was added to carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.).
10 parts by weight, 1 part by weight of potassium salt of benzylic acid derivative (Japan Carlit Co., Ltd., LR-147), low molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
Styrene-acrylic toner V was prepared. The particle size of this toner measured with a Coulter Counter (manufactured by Coulter) was 4 to 15 μm, and the average particle size was 6 μm.

Manufacture of Developer A coating carrier (particle diameter 60) prepared by coating the styrene-acrylic toner V prepared above with a ferrite carrier as a carrier is used as an acrylic modified silicone resin.
˜100 μm average particle size 90 μm) was blended so that the toner / carrier became 4/96 (weight ratio), and mixed with a V-type blender to prepare a developer V. The blow-off charge amount of the developer was measured and found to be -12 μc / g.

Comparative Example 1 85 parts by weight of styrene-acrylic resin 5 produced in Synthesis Example 5, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight, potassium salt of a benzylic acid derivative (NR-147, manufactured by Nippon Carlit Co., Ltd.), 3 parts by weight, low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
Styrene-acrylic toner VI was prepared. The particle size of this toner measured with a coulter counter is 5 to 20.
The average particle size was 9 μm.

Manufacture of Developer A coating carrier (particle size 60 to 100 μm average particle size 90 μm) prepared by coating a ferrite carrier with an acrylic modified silicone resin on the prepared styrene-acrylic toner VI was used in a toner / carrier ratio of 4/96 (weight ratio). ) And mixed with a V-type blender to prepare a developer VI. Blow-off charge of developer is -15
It was μc / g.

Comparative Example 2 85 parts by weight of styrene-acrylic resin 6 produced in Synthesis Example 6, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight, potassium salt of a benzylic acid derivative (NR-147, manufactured by Nippon Carlit Co., Ltd.), 3 parts by weight, low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
Styrene-acrylic toner VII was prepared. The particle size of this toner measured with a coulter counter is 4 to 1
The average particle size was 5 μm and 6 μm.

Production of Developer A coating carrier (particle size 60 to 100 μm average particle size 90 μm) in which a ferrite carrier is coated on the prepared styrene-acrylic toner VII with an acrylic modified silicone resin has a toner / carrier ratio of 4/96 (weight ratio). ), And mixed with a V-type blender to prepare a developer VII. Blow-off charge of developer is -1
It was 9 μc / g.

Comparative Example 3 85 parts by weight of styrene-acrylic resin 7 produced in Synthesis Example 7, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight, potassium salt of a benzylic acid derivative (NR-147, manufactured by Nippon Carlit Co., Ltd.), 3 parts by weight, low-molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd., Viscole 66)
0P) 2 parts by weight were mixed and kneaded with a kneader PCM-30. Then, after coarse crushing with a hammer mill, fine crushing with a jet mill, and further classification with a zigzag classifier,
Styrene-acrylic toner VIII was prepared. The particle size of this toner measured with a coulter counter is 5 to 2
The average particle size was 5 μm and the average particle size was 12 μm.

Manufacture of Developer A coating carrier (particle size 60 to 100 μm, obtained by coating the prepared styrene-acrylic toner VIII with a ferrite carrier by an acrylic modified silicone resin,
(Average particle size 90 μm) is mixed so that the toner / carrier becomes 4/96 (weight ratio), and mixed by a V-type blender,
Developer VIII was created. Blow-off charge of developer is −
It was 13 μc / g.

Comparative Example 4 85 parts by weight of styrene-acrylic resin 1 produced in Synthesis Example 1, carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.)
10 parts by weight, 3 parts by weight of a nigrosine-based charge control agent (manufactured by Orient Chemical Industry Co., Ltd., Bontron S-34), and 2 parts by weight of low-molecular-weight polypropylene (manufactured by Sanyo Chemical Industry Co., Ltd., VISCOL 660P) were mixed and kneaded. It was kneaded with a machine PCM-30. Then, styrene-acrylic toner IX was prepared through coarse pulverization with a hammer mill, fine pulverization with a jet mill, and classification with a zigzag classifier. The particle size of this toner measured with a coulter counter is 4 to
The average particle size was 15 μm and the average particle size was 6 μm.

Manufacture of Developer A coating carrier (particle size 60 to 100 μm average particle size 90 μm) in which a ferrite carrier is coated with an acrylic modified silicone resin on the prepared styrene-acrylic toner IX has a toner / carrier ratio of 4/96 (weight ratio). ) And mixed with a V-type blender to prepare developer IX. Blow-off charge of developer is -22
It was μc / g.

Comparative Example 5 Styrene-acrylic resin 185 produced in Synthesis Example 1 (85 parts by weight), carbon black (Mitsubishi Chemical Co., Ltd., # 44)
10 parts by weight, 3 parts by weight of a zinc salt of a salicylic acid derivative (manufactured by Orient Chemical Industry Co., Ltd., Bontron E-84), and 2 parts by weight of low molecular weight polypropylene (manufactured by Sanyo Chemical Industry Co., Ltd., Viscole 660P) were mixed and kneaded. It was kneaded with a machine PCM-30. Then, styrene-acrylic toner X was prepared through coarse pulverization with a hammer mill, fine pulverization with a jet mill, and classification with a zigzag classifier. The particle size of this toner measured with a coulter counter is 5
˜20 μm, average particle size was 6 μm.

Production of Developer A coating carrier (particle size 60 to 100 μm average particle size 90 μm) in which a ferrite carrier is coated on the prepared styrene-acrylic toner X with an acryl-modified silicone resin has a toner / carrier ratio of 4/96 (weight ratio). ) And mixed with a V-type blender to prepare a developer X. Blow-off charge of developer is -26
It was μc / g.

The characteristics of each developer were evaluated by the following evaluation methods.

Image Evaluation (Image Forming) Method Laser beam printer (photoreceptor: τ-type metal-free phthalocyanine pigment for charge generation layer, organic photoreceptor using butadiene derivative for charge transport layer, dot density: 600 dp
i, printing speed: 10 sheets / minute, a semiconductor laser, a magnetic brush developing machine, a two-component reversal developing system, a heat roll fixing, a bias voltage of −100 v) were used for evaluation.

(A): Line image density Using the laser beam printer described above, the developer prepared above was used to output the letter "I". The density of the letter "I" was measured with a microphotometer manufactured by Union Optical Co., Ltd. The measured values were converted to Macbeth concentration values and judged.

(B): Area image density In the same manner as the line image density, an image of 3 × 3 cm was output. The density of the central portion was measured using a Macbeth densitometer and judged.

(C): Fog Density A blank sheet was output in the same manner as the line image density. The fog density was determined from the difference between the density of the paper before output and the density of the paper after output using a reflection densitometer (TC-6DS manufactured by Tokyo Denshoku Co., Ltd.).

(D): Resolution 1.6 lines / inch, 2.0 in the same manner as the line image density.
Line / inch, 2.5 line / inch, 3.2 line / inch, 4.0 line / inch, 5.0 line / inch, 6.3 line / inch, 8.0 line / inch, 1
0.0 line / inch, 12.5 line / inch, 16
Output line drawing of line / inch. The maximum number of lines that the output image can read in detail is shown.

(E): Durability Each of the prepared developers was used in a copying machine at a temperature of 30 ° C.
10000 sheets were continuously copied under the condition of relative humidity of 80%. The scattering of the toner generated at this time was examined and judged by the following evaluation. 4: There is no toner scattering. 3: Some scattering of toner is seen. 2: A lot of toner is scattered. 1: A large amount of toner is scattered.

(F): Offset resistance Sanyo Denki Co., Ltd. Shatrex 806 Copier was modified to change the fixing temperature of the heat fixing roll of the copying machine from 60 ° C to 230 ° C, and each toner was copied. An unfixed image was output using a machine. Using the output unfixed image, the fixing temperature was changed and the temperature range in which offset did not occur was investigated.

(G): Fixability The output unfixed image was fixed at a temperature of 190 ° C. using the same fixing device as used in the offset resistance evaluation. Then, a scotch tape was attached to the fixed image, and peeled off after 10 minutes, and the change in image density was evaluated by the following formula. Fixability (%) = (concentration after peeling off cellophane tape / concentration before peeling off cellophane tape) × 100 The evaluation results of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1.

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[Table 1]

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INDUSTRIAL APPLICABILITY The dry toner and developer of the present invention are excellent in a wide range of anti-offset property, line image print density and surface image print density, and can obtain a high-definition image with less fog. Further, the developer can have a long life. Therefore, the image forming method using the developer according to the present invention is
An image having excellent image quality can be obtained for a long time in an electrophotographic copying machine, a laser beam printer, or the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location 7144-2H G03G 9/10 352 (72) Inventor Takashi Ikeda 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture No. Hitachi Chemical Co., Ltd. Yamazaki Factory

Claims (7)

[Claims] 1. A styrene-acrylic resin containing 10 to 50% by weight of a gel component and a compound represented by formula (I) as a charge control agent: A dry toner containing a metal salt of a benzylic acid derivative represented by (where M is an alkali metal). 2. The dry toner according to claim 1, wherein the toner contains a metal salt of a benzylic acid derivative in an amount of 0.1 to 5% by weight. 3. A developer containing the dry toner according to claim 1 and a carrier. 4. The developer according to claim 3, wherein the carrier is a ferrite carrier. 5. The developer according to claim 3, wherein the carrier is coated with a silicone resin or a modified silicone resin. 6. The electrostatic latent image formed on a photoconductor is brought into contact with the developer according to claim 3, 4 or 5 to visualize the image, and the image is transferred to a support and fixed. Image forming method. 7. The image forming method according to claim 6, wherein the photoreceptor is an organic photoreceptor having a phthalocyanine-based pigment as a charge generation layer.