JP2008077026A - Electrostatic charge image developing black toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which is excellent in low temperature fixing property, offset resistance, fluidity, blocking resistance and charging characteristic and has a long life. <P>SOLUTION: The electrostatic charge image developing black toner comprises: toner mother particles which at least contain binder resin, colorant and releasing agent; and inorganic oxide of which the surface is treated with silicone oil, wherein the releasing agent is a hydrocarbon type wax which has an normal paraffin content of 35 to 65 mass% and has a melting point of 60 to 90°C. Further, the hydrocarbon type wax is characterized in that the content of hydrocarbon compound having the number of carbon of 29 or less is 1 mass% or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a black toner for developing an electrostatic image used in electrophotography, electrostatic recording, magnetic recording, and toner jet.

In a copying machine, a facsimile receiving apparatus, a printer that outputs data from a computer, and the like, an electrophotographic method or an electrostatic recording method has been widely used as a method for obtaining a copy or recorded image. Typical examples of the copying machine and printer using the electrophotographic method or the electrostatic recording method include an electrophotographic copying machine, a laser beam printer, a printer using a liquid crystal array, and an electrostatic printer. In the electrophotographic method or the electrostatic recording method, an electrostatic latent image (electrostatic charge image) is formed on an electrostatic charge image carrier such as an electrophotographic photosensitive member or an electrostatic recording member by various means, and this is used as a developer. The resulting toner image is transferred to a transfer material such as paper as necessary, and fixed by heating, pressing, heating and pressing, or solvent vapor to obtain a final toner image, while electrostatic charge Toner remaining without being transferred onto the image bearing member is removed by a cleaning means, and the above steps are repeated again to obtain a copy or a recorded matter sequentially. As a method for obtaining an image or a recorded image using toner, in addition to the method using an electrostatic latent image, a magnetic latent image is formed on a magnetic recording material, and the magnetic latent image is developed using a magnetic toner. In addition, a magnetic recording method for obtaining a toner image, or a toner jet method for forming a toner image by flying the toner using the electrical characteristics of the toner are also known.

By the way, as a method for developing the electrostatic image, a method using a liquid developer composed of fine toner dispersed in an electrically insulating liquid, a colorant, a magnetic material, and the like are dispersed in a binder resin. A method using powder toner together with carrier particles, a method using magnetic toner in which a magnetic material is dispersed in a binder resin, and developing without using carrier particles are known. Among these methods, in recent years, a dry development method using powder toner or magnetic toner is mainly employed.

In recent years, electrophotographic copying machines, printers, and the like have become smaller and more personalized, and at the same time, higher speed has been required, and further reduction in energy has been required. Accordingly, various attempts have been made to improve these devices in order to obtain a reliable and high-quality image stably at high speed and low energy over a long period of time by a mechanism as simple as possible. In addition to such improvements in the apparatus, various attempts have been made to improve the toner used for development.

For example, as an apparatus for fixing toner for developing an electrostatic charge image, a heat and pressure fixing apparatus using a heating roller, a roll-shaped or long heat-resistant film, a so-called fixing belt, and a fixing belt are used. 2. Description of the Related Art A heat and pressure fixing apparatus that conveys a belt and a transfer sheet while pressing a transfer sheet from the back with a pressure roller while facing a heating body and a transfer sheet developing surface and fixing the heat and pressure is widely used. In recent years, the heat source of the heating roller tends to be replaced by electromagnetic induction heating (IH) capable of saving power and saving power from a halogen lamp.

In these methods, when the toner image is fixed, the heating roller or the fixing belt is in direct contact with the toner image, so that heat is efficiently propagated to the toner. For this reason, the toner is melted quickly and smoothly with low energy. be able to. However, in such a method of fixing by heating and pressurizing, the molten toner and the heat roller or fixing belt are in direct contact with each other at the time of fixing, so that part of the molten toner is heated or fixed. When the transfer roller adheres to the surface of the belt and the heat roller or the fixing belt comes into contact with the transfer body such as paper again, the transfer toner adheres to the transfer body again, or when there is no transfer body, a heat roller or the like There is a problem that the toner transferred and adhered to the pressure roll is transferred to the pressure roll and causes a so-called offset phenomenon such that the next transfer body adheres to the back surface of the transfer body when passing through the fixing device, and the transfer body is soiled. In order to eliminate this toner offset, an anti-offset liquid such as silicone oil is supplied to the transfer roller or the like, but there are problems such as paper stickiness and complicated apparatus.

In contrast, it has been proposed that the toner itself contains a releasable substance, melts the releasable substance by heating during fixing, and supplies a releasable liquid from the toner to prevent the toner offset phenomenon. A number of waxes such as low molecular weight polyethylene, low molecular weight polypropylene, hydrocarbon waxes, natural waxes, modified waxes obtained by modifying these have been proposed as such releasable substances (see, for example, Patent Documents 1 to 5). Attempts have also been made to further improve the fixability by adding a plurality of types of waxes (see, for example, Patent Document 6). However, these waxes added for imparting releasability to the toner are not compatible with the binder resin in the first place and are difficult to uniformly disperse in the toner. In addition, if a large amount of wax is added to the toner to prevent the toner offset phenomenon, the wax is unevenly distributed and the wax is liberated when the toner is finely pulverized. Filming to particles or the like occurs, resulting in deterioration of a developed image, and problems such as a decrease in toner fluidity and blocking. Further, low molecular weight polyethylene and low molecular weight polypropylene have a problem that the melting point is as high as 100 ° C. or higher, and the low-temperature fixability cannot be sufficiently achieved.

Furthermore, in recent years, there has been a demand for a toner having a smaller particle size and higher functionality in response to demands for higher image quality and higher resolution of electrophotographic images. In order to cope with this, a method for producing a toner by a polymerization method has attracted attention. As a method for producing a toner by a polymerization method, a colorant in a polymerizable monomer that is a raw material of a binder resin, and a polymerization initiator, a dispersant, a crosslinking agent, a charge control agent, if necessary,
A polymerizable monomer composition is prepared by dissolving or dispersing a release agent, polar resin, and other additives, and a dispersion stabilizer prepared in advance for the resulting polymerizable monomer composition is contained. Is put into an aqueous dispersion medium to be granulated into fine particles by using a stirrer, and then the polymerizable monomer in the granulated particles is polymerized to solidify the particles, followed by filtration, washing and drying. To obtain toner particles having a desired particle size and composition.

The toner using the above polymerization method is a toner having a small particle size with a sharp particle size distribution and can obtain an image with excellent image quality. However, in the suspension polymerization method in an aqueous dispersion medium, There is a problem that it is difficult to control the dispersion state of the wax existing in the resin.

Therefore, an electrostatic charge image developing toner excellent in blocking resistance and offset resistance, free from problems such as pulverization during toner production and uneven distribution of wax during polymerization, and excellent in chargeability and low-temperature fixability, and this There is a demand for a wax capable of forming a toner having such excellent characteristics. There is also a need for an image forming method that can stably form a good quality toner-fixed image for a long period of time without offset even when no offset preventing liquid is used.
Japanese Patent Publication No.52-3304 JP-A-10-73951 JP-A-10-125095 JP 2000-321815 A JP 2003-84483 A Japanese Patent Laid-Open No. 3-28789

An object of the present invention is to provide a black toner for developing an electrostatic image that does not have the above-mentioned problems.

Another object of the present invention is to provide a black toner for developing an electrostatic image having excellent low-temperature fixability, offset resistance, fluidity, blocking resistance, and charging characteristics.

Furthermore, an object of the present invention is to provide a black toner for developing an electrostatic charge image, in which the above-mentioned various characteristics can be arranged side by side without any contradiction and excellent in toner pulverization property and wax dispersion controllability.

As a result of intensive studies to solve the above-described conventional problems, the present inventors have found that the content of normal paraffin as a release agent in toner base particles containing at least a binder resin, a colorant and a release agent is 35. By using a hydrocarbon wax having a melting point of 60 to 90 mass% and a melting point of 60 to 90 ° C., and an inorganic oxide obtained by treating the surface with silicone oil as an external additive, low-temperature fixability and blocking resistance as a toner It has been found that a copy or recorded image having excellent offset resistance and a desired density can be stably obtained for a long period of time, and that there is no problem of toner pulverization property and wax dispersibility at the time of toner production. Invented.

That is, the present invention relates to the following black toner for developing electrostatic images (1) to (5).
(1) A black toner for developing an electrostatic image comprising toner base particles containing at least a binder resin, a colorant and a release agent, and an inorganic oxide obtained by treating the surface with silicone oil, the release agent Is a hydrocarbon wax having a normal paraffin content of 35 to 65 mass% and a melting point of 60 to 90 ° C.
(2) The hydrocarbon wax has a content of 1% by mass of hydrocarbon compounds having 29 or less carbon atoms.
The black toner for developing an electrostatic image according to (1), characterized in that:
(3) The black toner for electrostatic image development according to (1) or (2), wherein the hydrocarbon wax has a penetration of 12 to 20.
(4) The black toner for developing an electrostatic charge image according to any one of (1) to (3), wherein the binder resin is a polyester resin.
(5) The black toner for developing an electrostatic charge image according to any one of (1) to (3), wherein the binder resin is a styrene resin.

The black toner for developing an electrostatic image of the present invention is excellent in low-temperature fixability, offset resistance, blocking resistance, fluidity, fixability, and image recording properties, and the toner component is a photoreceptor, developer carrier, and the like. It can be suitably used for developing an electrostatic latent image formed in electrophotography, electrostatic recording method, magnetic recording method, toner jet method and the like.

The black toner for developing an electrostatic charge image of the present invention can produce a toner free from problems such as uneven distribution of wax in the toner regardless of the production method of the toner, and is excellent in toner pulverization.

By using an inorganic oxide whose surface is treated with silicone oil as an external additive,
Adhesion of the toner component to the photoreceptor could be suppressed.

  Hereinafter, the present invention will be described in more detail.

The release agent (wax) used in the black toner for developing an electrostatic charge image of the present invention comprises a hydrocarbon wax having a normal paraffin content of 35 to 65% by mass and a melting point of 60 to 90 ° C. It is a feature. The remaining components other than normal paraffin are mainly or entirely made of isoparaffin. The content of normal paraffin is preferably 40 to 60% by mass, more preferably 44 to 57% by mass. When the content of normal paraffin in the hydrocarbon wax exceeds 65% by mass, the dispersibility of the hydrocarbon wax in the toner or the binder resin is deteriorated. In particular, when a polyester resin is used as the binder resin, there is a problem that the wax becomes incompatible. On the other hand, when the normal paraffin content of the hydrocarbon wax is less than 35% by mass, the wax itself becomes soft, and the toner components are fixed and fused in the pulverizer during the production of the toner, so that pulverization is difficult. The problem that becomes. Further, the release agent used in the black toner for developing an electrostatic charge image of the present invention contains 60 to 35% by mass of a hydrocarbon component other than normal paraffin mainly or entirely made of isoparaffin, thereby dispersing in the binder resin. Sexually improved. This effect is particularly effective when a polyester resin is used. The total amount of normal paraffin and isoparaffin is usually 90% by mass or more, and the remaining components include cycloparaffin and the like.

Furthermore, the melting point of the release agent used for the black toner for developing an electrostatic image of the present invention is preferably 60 to 90 ° C. from the viewpoint of low-temperature fixability and offset resistance, and more preferably 70 to 85 ° C. More preferably, it is 73-83 degreeC. If the melting point of the release agent is lower than 60 ° C., offset is likely to occur at the time of fixing, resulting in a problem of deterioration in storage stability (storage stability) as a toner. On the other hand, when the temperature is higher than 90 ° C., it is impossible to meet the demand for low temperature fixability.

The release agent used in the black toner for developing an electrostatic charge image of the present invention preferably has a hydrocarbon compound content of 29 or less carbon atoms of 1% by mass or less, more preferably 0.5% by mass.
It is as follows. When the content of the hydrocarbon compound having 29 or less carbon atoms exceeds 1% by mass, the problem of toner fluidity and the problem of toner blocking during storage are increased, which is not preferable. Furthermore, about the content rate of a C30-C44 hydrocarbon, it is 80-87 mass%.
Moreover, it is preferable that it is 13-20 mass% about the content rate of a C45 or more hydrocarbon. The sum total of hydrocarbons having 29 or less carbon atoms, 30 to 44 carbon atoms, and 45 or more carbon atoms is 100.
% By mass.

The black toner for developing an electrostatic image of the present invention contains the release agent, and the content of the release agent in the toner is 1 with respect to 100 parts by mass of the resin component in the toner. It is preferably ˜20 parts by mass, and more preferably 2 to 10 parts by mass. When the content of the release agent is less than 1 part by mass, the effect as a release agent is hardly exhibited, and when the content exceeds 20 parts by mass, the toner is softened by wax, the problem of filming by wax during development and cleaning, and the toner This causes problems such as a decrease in fluidity and toner blocking during storage.

The wax as a release agent used in the black toner for developing an electrostatic image of the present invention can be produced from petroleum wax as follows. That is, crude oil is first divided into fractions by distillation. Among these, the wax solid at room temperature separated from the vacuum distillation effluent is called paraffin wax, and the wax solid at room temperature separated from the vacuum distillation residue oil or heavy distillate oil is microcrystalline wax ( Micro-wax), semi-solid wax separated from vacuum distillation residue oil at room temperature is called petrolactam, and these are collectively called petroleum wax. These paraffin wax and mylocrystalline wax can be further purified by a method of separating and removing a low melting point component using a press sweating method or a solvent deoiling method. The wax used in the present invention is produced by selectively producing a suitable wax from paraffin-based crude oil according to the content and melting point of normal paraffin and further refining it.

More specifically, the wax used in the present invention is a high melting point paraffin wax, BARECO BW3250 (manufactured by Toyo Petrolite), a low melting point micro wax, B SQUARE 175A, Victory (Victory). The wax having the above-mentioned characteristics can be formed by adjusting the processing conditions of the solvent extraction method or the press sweating method, which are methods for producing petroleum hydrocarbons such as those manufactured by Toyo Petrolite.

In the above description, the method for producing the wax used in the present invention from petroleum wax has been described. Of course, the wax used in the present invention can also be produced from a wax produced by synthesis.

As the binder resin used in the black toner for developing an electrostatic charge image of the present invention, any conventionally known binder resin for toner can be used. Examples of binder resins that can be used include homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, and the like; and styrene-p-chlorostyrene copolymers, styrene-vinyltoluene. Copolymer, styrene-vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene -Vinylmethyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, etc. Styrene copolymer; Poly Vinyl, phenol resins, natural resin modified phenol resins, natural resin-modified maleic acid resin,
Acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin,
Examples thereof include polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, and petroleum resin. A crosslinked styrene copolymer is also a preferred binder resin.

In the styrene copolymer included in the styrene polymer, the comonomer for the styrene monomer may be, for example, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, acrylic acid- Monocarboxylic acid having a double bond such as 2-ethylhexyl, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, or a substituted product thereof; ,
Dicarboxylic acids having a double bond such as maleic acid, methyl maleate, butyl maleate and dimethyl maleate and their substituted products; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; for example, ethylene, propylene and butylene Ethylene-based olefins such as vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone;
For example, vinyl monomers such as vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; These may be used alone or in combination of two or more.

Commercially available resins for styrene-based copolymers include CPR100, CPR120, CPR2
00, CPR220, CPR250, CPR300, CPR330, CPR350, CP
R400, CPR600B (manufactured by Mitsui Chemicals, Inc.).

As a crosslinking agent used when producing a crosslinked styrene-based copolymer, mainly 2
Compounds having at least one polymerizable double bond are used, for example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, etc. A carboxylic acid ester having two double bonds: divinylaniline, divinyl ether,
Divinyl compounds such as divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups are used alone or as a mixture. As styrenic polymer,
A styrenic copolymer having at least one peak in a region of 3 × 10 ^{3 to} 5 × 10 ⁴ in a molecular weight distribution measured by GPC and having at least one other peak or shoulder in a region of 10 ⁵ or more. It is preferable from the viewpoint of fixability.

In producing the vinyl polymer, a polymerization initiator is used. Any conventionally known polymerization initiator can be used. Polymerization initiators include benzoyl peroxide, lauroyl peroxide, tertiary butyl hydroperoxide, tertiary butyl peroxybenzoate, ditertiary butyl peroxide, cumene hydroperoxide, dicumyl peroxide, azoisobutyrate. Ronitrile, azobisvaleronitrile, and the like have been preferably used conventionally. The use ratio of the polymerization initiator to the vinyl monomer is generally 0.2 to 5% by mass. The polymerization temperature is appropriately selected according to the type of monomer and initiator used.

On the other hand, a polyester resin is also preferable as a binder resin used in the black toner for developing an electrostatic image of the present invention. Examples of the alcohol component constituting the polyester resin include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1
Diols such as bisphenol derivatives represented by the following general formula 3; glycerin, 5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, bisphenol A hydrogenated Polyhydric alcohols such as sorbitol, sorbitan, pentaerythritol and trimethylolpropane are preferable.

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10.)
Examples of the acid component include divalent carboxylic acids such as benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or anhydrides thereof; alkyls such as succinic acid, adipic acid, sebacic acid, and azelaic acid. Dicarboxylic acids or anhydrides thereof; or succinic acid or anhydrides substituted with an alkyl group having 16 to 18 carbon atoms; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid, or anhydrides thereof; On the other hand, preferable examples of the trivalent or higher carboxylic acid serving as a crosslinking component include trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, and anhydrides thereof.

A preferred alcohol component is a bisphenol derivative represented by the above general formula 3, and a preferred acid component is phthalic acid, terephthalic acid, isophthalic acid or its anhydride, succinic acid, n
-Dodecenyl succinic acid or its anhydride, dicarboxylic acids such as fumaric acid, maleic acid and maleic anhydride, and tricarboxylic acids such as trimellitic acid or its anhydride.

Further, as the crosslinking component of the polyester resin, in addition to using the above-described trivalent or higher carboxylic acid and trivalent or higher polyhydric alcohols, urethane cross-linking (isocyanate cross-linking) using a polyvalent isocyanate compound is also preferable. .

Furthermore, as the polyester resin, a urethane-modified polyester resin is also preferable. The urethane-modified polyester resin can be obtained by adding a polyvalent isocyanate compound to a polyester resin and mixing and reacting them by melt kneading. The cross-linking reaction using polyvalent isocyanate is performed by addition reaction between hydroxyl group and isocyanate group in the polyester resin, and obtains urethane bond. It is very reactive, especially in short reaction time in the melt-kneading process. It is a suitable compound for crosslinking to a molecular weight or increasing the molecular weight.

The polyvalent isocyanate compound is a compound having a divalent or higher isocyanate group, and examples include diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and tetramethylene diisocyanate. .

The acid value of the polyester resin is preferably 40 mgKOH / g or less as a toner. An acid value of 40 mgKOH / g or less is preferable because it can prevent a significant decrease in frictional chargeability after standing for a long time under high humidity. When it is 30 mgKOH / g or less, the triboelectric charging property with the increase in the number of copies is stabilized, which is more preferable. In particular, in the case of a polyester resin in which the acid value of the toner falls within the range of 1 to 20 mg KOH / g, the triboelectric chargeability does not decrease even after being left for a long time under high humidity. It is preferable because the charging amount is completely restored, the charging speed is good, and the charging amount does not gradually increase as the number of copies increases.

In the present invention, the acid value can be measured according to the method of JIS K-0070. The acid value is represented by the number of mg of potassium hydroxide required to neutralize 1 g of toner. However, when the toner contains a magnetic substance, the residue obtained by eluting the magnetic substance with an acid is 1 g of toner.

In the present invention, a hybrid resin in which a vinyl polymer unit and a polyester unit are chemically bonded, such as a graft copolymer using a vinyl polymer as a trunk polymer and a polyester unit as a branch polymer, is also used. be able to. As the vinyl resin, a monomer having a carboxyl group or a hydroxyl group is preferably contained as a polymerization unit.
As other polymerization units, the monomers exemplified in the vinyl polymer are used as appropriate. Furthermore, as a monomer component which forms a polyester unit, the said alcohol component, acid component, etc. which are used in order to manufacture a polyester resin are used. For these hybrid resins, for example, the production method described in Patent Document 5 can be referred to.

In the present invention, the binder resin is preferably 40 to 95 parts by mass per 100 parts by mass of the toner.

The glass transition temperature (Tg) of the binder resin is preferably in the range of 50 to 70 ° C. In the present invention, the glass transition temperature (Tg) is a differential scanning calorimeter (DSC-5 manufactured by Shimadzu Corporation).
0), the value of the intersection of the base line extension below Tg when measured at a temperature elevation rate of 10 ° C./min and the tangent to the endothermic curve near Tg was determined and measured.

As the colorant that can be used in the black toner for developing an electrostatic charge image of the present invention, any colorant known to be used in the production of conventional toners can be used. Among them, it is usually preferable to use carbon black or magnetic powder.

As carbon black, various types such as furnace black, channel black, acetylene black, etc. can be used. However, furnace black carbon is preferable because it has the effect of reducing fog (soil on the white background) in image characteristics. It is. Carbon black can be used alone or in admixture of two or more. Carbon black is usually added in an amount of 3 to 15 parts by mass, preferably 4 to 10 parts by mass with respect to 100 parts by mass of the binder resin. When magnetic powder is used as a colorant in the magnetic toner, carbon black may be used as necessary.

In the black toner for developing an electrostatic image of the present invention, a magnetic powder may be internally added as a colorant to form a magnetic toner. The magnetic material that can be used may be any alloy or compound containing a ferromagnetic element that has been conventionally used in the production of magnetic toners. Examples of these magnetic materials include iron oxides such as magnetite, maghemite and ferrite, or compounds of divalent metals and iron oxides, metals such as iron, cobalt and nickel, or aluminums of these metals, cobalt, copper, lead, Examples include alloys of metals such as magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. These magnetic materials preferably have an average particle size determined by SEM of about 0.1 to 2 μm, more preferably about 0.1 to 0.5 μm. The content of the magnetic substance in the toner is about 20 to 200 with respect to 100 parts by mass of the binder resin.
Part by mass, preferably 40 to 150 parts by mass. Further, the saturation magnetization of the toner is 15
-35 emu / g (measuring magnetic field 1 kilo-Oersted) is preferred.

The black toner for developing an electrostatic charge image of the present invention may contain a conventionally known charge control agent as required. As the charge control agent, a positive charge control agent or a negative charge control agent is used according to the polarity of the electrostatic image on the electrostatic latent image carrier to be developed. Examples of the positive charge control agent include nigrosine dyes and fatty acid metal derivatives, basic dyes such as triarylmethane dyes, quaternary ammonium salts (for example, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutyl Benzylammonium tetrafluoroborate), organotin oxide (eg, dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide), diorganotin borate (dibutyltin borate, dioctyltin borate, dicyclohexyltin borate), and polymers having amino groups Donating substances and the like can be used alone or in combination of two or more. Of these, nigrosine dyes and quaternary ammonium salts are preferred. On the other hand, negative charge control agents include compounds having carboxyl groups, for example, metal complexes of monoazo dyes, metal complex dyes such as chromium-containing organic dyes (copper phthalocyanine green, chromium-containing monoazo dyes), aryloxy such as salicylic acid or salicylic acid derivatives. Examples thereof include divalent or trivalent metal salts, metal chelates (complexes) of carboxylic acids, fatty acid soaps, and metal salts of naphthenic acid. These charge control agents are usually used at a ratio of 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, with respect to 100 parts by mass of the binder resin.

The black toner for developing an electrostatic charge image of the present invention preferably has a volume average particle size of 3 to 35 μm, more preferably 4 to 20 μm. In the case of a small particle size toner, the average particle size is 4 to 1
It is about 0 μm. When the electrostatic charge image developing black toner of the present invention is a magnetic toner,
It preferably has an electric resistance of 10 ¹⁰ Ω · cm or more, preferably 10 ¹³ Ω · cm or more.
The toner particle size distribution can be measured using, for example, a Coulter counter (multisizer). The black toner for developing an electrostatic charge image of the present invention was measured with Multisizer 3 (manufactured by Beckman Coulter) under the condition of an aperture diameter of 100 μm.

In the black toner for developing an electrostatic image of the present invention, it is important to use an inorganic oxide treated with a silicone oil having a fluidizing agent function as an external additive.

By using an inorganic oxide treated with silicone oil, the toner component is a photoreceptor,
It has the effect of making it difficult to cause problems such as drum filming and sleeve filming due to adhering to the developing sleeve. This is because silicone oil has excellent releasability and slipperiness, and prevents adhesion to the surface of the photosensitive drum and filming, and prevents embedding of inorganic oxides (external additives) in the toner. It is because it plays the effect of.
In particular, since the wax used in the present invention contains isoparaffin and the melting point is in the range of 60 to 90 ° C., the toner component easily causes the filming when printing more than 50,000 sheets as a toner. It is effective to use an inorganic oxide surface-treated with silicone oil as a fluidizing agent. Further, the fluidizing agent treated with silicone oil is less likely to be embedded in the surface of the toner base particles, has excellent printing durability, and the image quality is stable over a long period of time.

As the base material of the inorganic oxide, silica, alumina, titania, magnesia, amorphous silicon
Fine powders such as aluminum co-oxide and amorphous silicon-titanium co-oxide can be used. The fluidizing agent as an external additive has not only the purpose of imparting fluidity to the toner but also the role of imparting and controlling toner chargeability. That is, the external additive adheres to the outermost part of the toner and thus has a great influence on the chargeability of the toner. It is preferable to select an appropriate silicone oil material.

Examples of silicone oils that can be preferably used for the surface treatment include straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil, and modified silicone oils. Examples of the modifying group used in the modified silicone oil include methylstyrene group, long chain alkyl group, polyether group, carbinol group, amino group, epoxy group, carboxyl group, higher fatty acid group, mercapto group, methacryl group and the like. .

Examples of silica that has been surface-treated with a commercially available silicone oil include R20.
2, RY200, RY200S (manufactured by Nippon Aerosil Co., Ltd.), H2015EP, H205
There are 0EP, H2150VP, H3050VP, H15, H20, H30 (manufactured by Wacker Chemical Co., Ltd.), etc., and these may be used.

The black toner for developing an electrostatic charge image of the present invention further contains, as necessary, known additives used in the production of the toner, such as a lubricant, an abrasive, a conductivity imparting agent, and an image peeling preventing agent. Alternatively, it can be externally added. Examples of these additives include polytetrafluoroethylene and zinc stearate as lubricants, and silicon nitride, cerium oxide, silicon carbide, strontium titanate (ST, HST-1, manufactured by Fuji Titanium Co., Ltd.) as abrasives. HPST-1,
HPST-2 and the like), calcium titanate (CT and the like manufactured by Fuji Titanium Co., Ltd.), tungsten carbide, calcium carbonate, and those obtained by hydrophobizing them. Examples of the conductivity imparting agent include carbon black and tin oxide. In addition, fine powders of fluorine-containing polymers such as polyvinylidene fluoride are preferable from the viewpoints of fluidity, abrasiveness, charge stability, and the like. Strontium titanate, calcium titanate, etc. have been used preferably as a polishing agent for toners since 1983, and even in the present after the 21st century, processes are still added to strontium titanate and calcium titanate. However, new patent applications have been filed for use.

The amount of these external additives such as a lubricant, an abrasive, and a conductivity imparting agent is 100 parts by mass of the toner, the lubricant is 0.1 to 2 parts by mass, the abrasive is 0.2 to 5 parts by mass, Conductivity imparting agent, 0.
05-2 parts by mass are preferred. Further, these external additives often have charge controllability with respect to the toner, so that an appropriate one may be selected and used according to the charge characteristics of the toner.

The black toner for developing an electrostatic charge image of the present invention can be produced using a conventionally known toner production method. The toner production methods are roughly classified into two types: a pulverization method obtained through kneading and pulverization steps, and a polymerization method obtained by chemical polymerization. In the case of the pulverization method, for example, the toner constituent materials as described above are sufficiently mixed by a mixer such as a ball mill or a Henschel mixer, and then kneaded well using a thermal kneader such as a hot roll kneader, a uniaxial or biaxial extruder. Then, after cooling and solidification, a method of manufacturing by a method of coarsely pulverizing mechanically using a pulverizer such as a hammer mill, then finely pulverizing with a jet mill, a mechanical pulverizer, etc., and then classifying.

On the other hand, in the case of the polymerization method, a method for producing toner by the so-called microcapsule method in which other toner constituent materials are dispersed in a binder resin solution and then spray-dried, and a predetermined material as a monomer for forming the binder resin And a method of obtaining a toner by emulsion or suspension polymerization. In the emulsion polymerization method, resin particles having a particle size of submicron are associated with an internal additive such as a colorant or wax that has been pre-emulsified in water in the aggregation step to obtain a particle size of a desired toner size. In the suspension polymerization method, polymerization is performed by dispersing and heating necessary materials such as a polymerization initiator, a colorant, a wax, and a charge control agent in a monomer.

The toner thus prepared is mixed with a carrier and used as a two-component dry toner, or the toner alone is used, for example, as a one-component magnetic developer. As the carrier, any carrier conventionally used in a two-component dry developer can be used. Examples of such carriers include ferromagnetic powder such as iron powder or alloy powder of ferromagnetic metal, metal oxide such as iron oxide, ferrite powder composed of elements such as nickel, copper, zinc, magnesium, barium, Magnetic powder carrier made of magnetic powder such as magnetite powder, magnetic powder resin coated carrier coated with these magnetic powder with resin, binder carrier made of magnetic powder and binder resin, glass beads with or without resin coating, etc. Can be mentioned. These carriers usually have a particle size of about 15 to 500 μm, preferably about 20 to 300 μm.

Examples of the coating resin for the magnetic powder resin-coated carrier include silicon-containing resins such as polyethylene and silicone resin, fluorine-containing resins, styrene resins, acrylic resins,
Styrene-acrylic resin, polyvinyl acetate, cellulose derivative, maleic acid resin, epoxy resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl bromide, polyvinylidene bromide, polycarbonate, polyester, polypropylene, phenol resin, polyvinyl alcohol, Fumarate resin, polyacrylonitrile, polyvinyl ether, chloroprene rubber, acetal resin, ketone resin, xylene resin, butadiene rubber, styrene-butadiene copolymer, polyurethane, polyamide resin, ionomer resin, polyphenylene sulfide resin, and the like can be used. Among these, fluorine-containing resins and silicon-containing resins are particularly preferable because the formation of spent toner is small. This magnetic powder resin coated carrier includes conductive fine particles (carbon black, conductive metal oxide, metal powder), inorganic filler (
(Silica, silicon nitride, boron nitride, alumina, zirconia, silicon carbide, boron carbide, titanium oxide, clay, talc, glass fiber), the charge control agent exemplified above, and the like may be included as necessary. The resin coating thickness on the carrier core material is preferably about 0.1 to 5 μm.

In the present invention, the melting point of the wax is a value measured according to ASTM D87, and the penetration is a value measured according to ASTM D1321.

Further, the content of the hydrocarbon compound having 29 or less carbon atoms and the content of the hydrocarbon compound having 30 to 44 carbon atoms in the wax are based on data measured by a gas chromatography method (GC). The total content of normal paraffin can be identified from the retention time of the standard substance, and the total components other than normal paraffin can be calculated from the amount of normal paraffin. The measurement by GC is performed, for example, under the following measurement conditions.
(GC measurement conditions)
This was performed by dissolving the wax in hot toluene and injecting it into the following gas chromatograph while hot under the following conditions. Aliphatic hydrocarbons in the wax were separated for each carbon chain length, and the carbon number distribution was measured by determining the ratio of the peak areas of each. The peaks appearing on the gas chromatograph were identified by collating with the chromatograms of the following standard solutions measured simultaneously. Since n-paraffins elute in order from those having the smallest number of carbon atoms, identification can be made with four types of n-paraffins.
Gas chromatograph: GC-380 manufactured by GL Sciences (using FID detector)
Column: Silica capillary column InertCap 1 (manufactured by GL Sciences Inc.)
Column temperature: 130-340 ° C. 3 ° C./min. Temperature rise detector, inlet temperature: 340 ° C
Carrier gas: 100 ml / min. N2
Sample injection volume: 2 μL
Identification standard reagent: Toluene (reagent special grade), n-tetracosane (n-C24 H50 reagent 1
Class), n-octacosane (n-C28 H58 reagent special grade), n-dotriacosane (n-
C32 H66 reagent grade 1) and n-hexane triacosane (n-C36 H74 reagent grade) were used.

Hereinafter, the present invention will be described more specifically with reference to production examples and examples, but the present invention is not limited to these examples.
Manufacture of wax Paraffin-based crude oil is cooled to precipitate the paraffin wax, and the squeezed wax (slack wax) obtained by squeezing and filtering it with a filter press separates the paraffin wax and oil by press sweating. By processing, waxes A to C having the following characteristics were produced. In addition, the component of the target paraffin wax can be adjusted by selecting paraffin base crude oil and adjusting the conditions (temperature etc.) in the press perspiration method.
[Wax A]
Melting point: 80.8 ° C
n-paraffin content: 53% by mass
Non-normal paraffin hydrocarbon compound content: 47% by mass
Content of hydrocarbon compound having 29 or less carbon atoms: 0.26% by mass
Content of hydrocarbon compound having 30 to 44 carbon atoms: 85.03 mass%,
Penetration (25 ° C): 10
Density: 0.940
Average molecular weight (osmotic pressure method): 520
Kinematic viscosity (100 ° C.): 8.0 cSt
[Wax B]
Melting point: 73.2 ° C
n-paraffin content: 36% by mass
Non-normal paraffin hydrocarbon compound content: 64% by mass
Content of hydrocarbon compound having 29 or less carbon atoms: 0.84% by mass
Content of hydrocarbon compound having 30 to 44 carbon atoms: 84.75% by mass
Penetration (25 ° C): 16
Density: 0.938
Average molecular weight (osmotic pressure method): 512
Kinematic viscosity (100 ° C): 84 Saybolt (SUS)
[Wax C]
Melting point: 82.7 ° C
n-paraffin content: 64% by mass
Non-normal paraffin hydrocarbon compound content: 36% by mass
Content of hydrocarbon compound having 29 or less carbon atoms: 0.53 mass%
Content of hydrocarbon compound having 30 to 44 carbon atoms: 87.24% by mass
Penetration (25 ° C): 9
Density: 0.942
Average molecular weight (osmotic pressure method): 524
Kinematic viscosity (100 ° C.): 10.0 cSt

55 parts by mass of a urethane-modified polyester resin, 43 parts by mass of a magnetic substance (magnetite), 0.5 parts by mass of an aromatic hydroxycarboxylic acid trivalent chromium salt compound, 1.5 parts by mass of wax A,
After mixing uniformly with a 20 L Henschel mixer, the twin screw extruder kneader PCM-30 (
(Ikegai Co., Ltd.) kneaded at a supply rate of 6 kg / hr and a discharge temperature of 150 ° C., cooled, and then passed through a 1 mm mesh with a sample mill to obtain a chip. Furthermore, after pulverizing using a mechanical pulverizer Kryptron KTM-1 type (manufactured by Earth Technica Co., Ltd.) having a rotor and a liner inside the pulverizer (feed amount 5 kg / hr, rotor rotational speed 5000 rpm), an airflow classifier (
(Nippon Pneumatic Co., Ltd., DS-2 type) to obtain negatively charged toner base particles having an average particle diameter of 10.5 μm. At this time, no fusion of the material to the rotor and liner during pulverization was observed. In addition, the distribution state of the wax contained in the obtained toner particles was confirmed by the following method. Table 1 shows the results of confirmation of the distribution state of the wax in the toner particles.
<Confirmation of wax distribution in toner particles>
Sampling the toner base particles (classified product) and the classified fine powder with an airflow classifier, and using a differential scanning calorimeter (DSC: DSC-60, manufactured by Shimadzu Corporation), the endotherm corresponding to the melting point of the wax in the first run. The peak calorific value was measured.

The smaller the difference in the amount of heat between the classified product and the classified fine powder, the more uniformly the wax is dispersed in the toner.
It can be said that it is blended. If the numerical value of the heat of wax of the classified fine powder is within 10% on the basis of the heat of wax of the classified product, it can be said that classification and blending are good. Very preferably it is within 5%. If it exceeds 10%, it becomes difficult to control the distribution of the wax in the production process, and it becomes impossible to reuse the classified fine powder, or the content of the wax in the toner particles is unevenly distributed. There also arises a problem that the image density fluctuates and fog increases.

Next, 0.3 parts by mass of silica fine powder treated with dimethyl silicone oil and 1.0 part by mass of tungsten carbide fine powder having an average primary particle size of 0.8 μm with respect to 100 parts by mass of the toner base particles obtained above. After mixing with a Henschel mixer, the mixture was sieved with a vibrating screen to obtain a magnetic black toner having negative chargeability.

The obtained black toner was tested and evaluated for storage stability, image density, fog density, fixability, and offset resistance based on the following test methods. The results of these tests are shown in Tables 2 and 3 together with the evaluation results of the wax dispersibility.
<Storage stability test and evaluation>
After sealing 40 g of the obtained magnetic black toner in a 200 ml glass container and leaving it in a high-temperature tank at 50 ° C. for 24 hours, the state of toner blocking was visually observed and evaluated based on the following evaluation criteria. went.

○: There is no occurrence of aggregation. Δ: There is aggregation but is easily loosened. ×: There is aggregation that is not easily loosened. ○ If the level is Δ, there is no problem in using the toner. Problems such as fusion and fixing in the developing machine resulting in locking of the developing machine and aggregation during storage occur.
<Image test>
Using the obtained magnetic black toner, an OPC drum is mounted on a commercially available digital copying machine iR-3300 (manufactured by Canon Inc.), and 10 ° C. in an environment of normal temperature and humidity (N / N: 23 ° C., 50% RH).
Ten thousand live-action tests were conducted.
<Fixability test and evaluation>
The fixed image was rubbed with an eraser (manufactured by dragonfly pencil: MONO), and the value calculated by [image density after rubbing / image density before rubbing] × 100 was expressed as fixing strength. 85% or more is a good value.
<Offset resistance test and evaluation>
After continuous copying of 200 images for fixing test, the sheet was stopped for 5 minutes, and then 20 blank sheets were passed through and evaluated based on the state of white paper stains. The evaluation results were based on the following criteria.

○: Paper stain did not occur ×: Paper stain occurred <Measurement of image density>
The image density was measured using a Macbeth photometer. The concentration may be 1.35 or more.
<Measurement of fog density>
This was done by measuring the reflectance with a photovolt. A value of 1.2% or less is a good value.
[Example 2]
Toner mother particles (classified product) and magnetic black toner were produced in the same manner as in Example 1 except that the wax B was used in place of the wax A of Example 1. During the production of the toner base particles of this example, no fusion of the material to the rotor and liner was observed during chip grinding.

Distribution state of wax in toner base particles, storage stability of toner, image density, fog density,
Fixability and offset resistance were tested and evaluated. The results are shown in Table 2 and Table 3.
[Example 3]
Toner mother particles (classified product) and magnetic black toner were produced in the same manner as in Example 1 except that the wax C was used in place of the wax A of Example 1. During the production of the toner base particles of this example, no fusion of the material to the rotor and liner was observed during chip grinding.

Distribution state of wax in toner base particles, storage stability of toner, image density, fog density,
Fixability and offset resistance were tested and evaluated. The results are shown in Table 2 and Table 3.
[Comparative Example 1]
Toner base particles (classified product) and magnetic black toner were produced in the same manner as in Example 1 except that Barico BW3250 (manufactured by Toyo Petrolite Co., Ltd.) was used in place of the wax A of Example 1.

The melting point of Varico BW3250 is 76.0 ° C., and the content of n-paraffin is 51% by mass.
The content of hydrocarbon compounds having 29 or less carbon atoms is 1.25% by mass, the content of hydrocarbon compounds having 30 to 44 carbon atoms is 88.09% by mass, and the total amount of hydrocarbons other than normal paraffin is 4%.
9 mass% and the penetration is 12.

Tests and evaluations of wax distribution in toner particles, toner storage stability, image density, fog density, fixability, and offset resistance were conducted in the same manner as in Example 1. The results are shown in Table 2 and Table 3.
[Comparative Example 2]
Example 1 except that microcrystalline wax D was used instead of wax A of Example 1
The toner mother particles were produced in the same manner as in Example 1, but the toner mother particles could not be produced because the wax was fused to the wall of the kneader.

The melting point of microcrystalline wax D is 79.0 ° C., the content of n-paraffin is 33% by mass, the content of hydrocarbon compounds having 29 or less carbon atoms is 2.60% by mass, and the number of carbons is 30.
The content of hydrocarbon compounds of .about.44 is 62.60% by mass, the total amount of hydrocarbons other than normal paraffin is 67% by mass, the penetration is 20, and the density is 0.932.
[Comparative Example 3]
Toner mother particles (classified product) and magnetic black toner were produced in the same manner as in Example 1 except that paraffin wax E was used in place of wax A in Example 1.

The melting point of paraffin wax E is 76.2 ° C., the content of n-paraffin is 85% by mass, the content of hydrocarbon compounds having 29 or less carbon atoms is 0.24% by mass, and hydrocarbons having 30 to 44 carbon atoms. The content of the compound is 84.65% by mass, the total amount of hydrocarbons other than normal paraffin is 15% by mass, the penetration is 7, and the density is 0.939.

Tests and evaluations of wax distribution in toner particles, toner storage stability, image density, fog density, fixability, and offset resistance were conducted in the same manner as in Example 1. The results are shown in Table 2 and Table 3.
[Comparative Example 4]
Toner base particles (classified product) and magnetic black toner were produced in the same manner as in Example 1 except that low molecular weight polypropylene F (Biscol 550P: manufactured by Sanyo Chemical Co., Ltd.) was used in place of the wax A of Example 1.

Distribution state of wax in toner base particles, storage stability of toner, image density, fog density,
Fixability and offset resistance tests and evaluations were performed in the same manner as in Example 1. The results are shown in Table 2 and Table 3.

The waxes A to C and Varico BW used in Examples 1 to 3 and Comparative Examples 1 to 4 below.
3250, microcrystalline wax D, paraffin wax E, polypropylene F
The physical properties of the toners are summarized in Table 1, and the evaluation results of the toners produced in Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Tables 2 and 3, respectively.

[Example 4]
89 parts by mass of styrene-butyl acrylate copolymer resin, carbon black (Monarch 8
80 parts made by Cabot Corporation), 2 parts by mass of nigrosine dye (Bontron N-04),
After 100 parts by weight of toluene was treated by a sand mill for 5 hours and dispersed, 36 parts by weight of a toluene dispersion of wax obtained by dispersing 2 parts by weight of wax A in 100 parts by weight of toluene was added and stirred well until uniform. Thus, an oil phase liquid was prepared. After 60 parts by mass of tricalcium phosphate and 40 parts by mass of water were mixed and dispersed in a ball mill for 8 hours, 6 parts by mass of tricalcium phosphate dispersion and 0.5 parts by mass of sodium dodecyl sulfate were placed in a mixer. A water phase solution was prepared by mixing for a minute. To the obtained aqueous phase liquid, 50 parts by mass of the oil phase liquid was added and mixed for 6 minutes with a mixer, and then heated in a 70 ° C. hot water bath to remove the organic solvent. After adding 100 parts by mass of 6N hydrochloric acid to remove tricalcium phosphate, 100 parts by mass of NaOH aqueous solution adjusted to pH 10 is added, stirred for 10 minutes, filtered, washed with water and dried to obtain a black having an average particle diameter of 10.5 μm. Toner mother particles were obtained.

Next, 0.3 parts by mass of silica fine powder treated with methylphenylsilicone oil and 0.2 parts by mass of conductive acid value tin fine powder were added to 100 parts by mass of the black toner base particles obtained above. After mixing with a mixer, the mixture was sieved with a vibrating sieve to obtain a positively charged black toner.

Using this black toner, a live-action test was conducted using a commercially available copying machine having a structure of a hot-pressure roll as a fixing device (Copying Machine FP-7113 manufactured by Matsushita Electric Industrial Co., Ltd.), and image density (initial and 100,000 sheets). Later image density values: measured at 1 cm × 1 cm, original density 1.2), fog (initial and 100,000 fog values), fixability, and offset resistance were evaluated. As a carrier, a silicone-coated ferrite carrier having an average particle size of 80 μm was used, and 96 parts of this carrier and 4 parts of black toner were mixed to prepare a developer. As a result, the initial image density was 1.38, after 1.8000 sheets, 1.39, and the fog was initially 0.6, after 8000 sheets, and the toner component did not adhere to the photosensitive member. There was no problem and no offset was found.
[Example 5]
To 100 parts by mass of the black toner base particles obtained in Example 4, 0.3 parts by mass of commercially available silica oil-treated silica R202 and 0.2 parts by mass of conductive acid value tin fine powder were added,
After mixing with a Henschel mixer, the mixture was sieved with a vibrating sieve to obtain a positively charged black toner. Further, as a result of performing the same test as in Example 5, the image density was 1.37 at the initial stage, and 1.
37, fog was 0.7 at the initial stage and 0.9 after 8000 sheets, no adhesion of the toner component to the photosensitive member, no problem of fixing property, and no occurrence of offset.

The black toner for developing an electrostatic charge image of the present invention is excellent in low-temperature fixability, and provides toner with excellent durability and printing durability without toner components adhering to a photoreceptor, a developing sleeve, etc. can do.

Claims (5)

A black toner for developing an electrostatic image comprising toner base particles containing at least a binder resin, a colorant and a release agent, and an inorganic oxide obtained by treating the surface with silicone oil, wherein the release agent is normal paraffin A black toner for developing electrostatic images, characterized in that it is a hydrocarbon wax having a content of 35 to 65 mass% and a melting point of 60 to 90 ° C. 2. The black toner for developing an electrostatic charge image according to claim 1, wherein the hydrocarbon wax has a content of a hydrocarbon compound having 29 or less carbon atoms of 1% by mass or less. The black toner for developing an electrostatic charge image according to claim 1 or 2, wherein the hydrocarbon wax has a penetration of 12 to 20. The black toner for electrostatic image development according to claim 1, wherein the binder resin is a polyester resin. The black toner for developing an electrostatic charge image according to claim 1, wherein the binder resin is a styrene resin.