JP2010049277A - Electrostatic charge image developer and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developer showing stable development and transfer performance to obtain high-definition printed images with no greasing without causing variation of friction charging performance, electric resistance, or the like when used as a two-component developer. <P>SOLUTION: The electrostatic charge image developer includes an electrostatic charge image toner containing resin and a coloring agent, and a carrier having a resin layer containing a resistance control agent on the surface of a carrier core material. The resin layer of the carrier has a density gradient of the resistance control agent in the thickness direction, and the density of the resistance control agent is lowered toward the surface of the resin layer. Moreover, the resistance control agent exists in the surface of the resin layer. An image forming method uses this electrostatic charge image developer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developer used in electrophotography, electrostatic recording method, or electrostatic printing method.

  As electrophotographic methods, various methods are described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748 (Patent Documents 1 to 3). Usually, a toner composition containing an electrostatic latent image formed on an electrostatic latent image carrier such as a photoconductive photosensitive member by charging and exposure, and then containing the colorant in a binder resin. In general, a visible image is formed by developing the toner image and transferring and fixing the obtained toner image onto a support such as transfer paper.

  In addition, there are many known development methods in electrophotography, but broadly speaking, a mixture of a carrier and toner composed of fine particles (20 to 500 μm) such as iron powder, ferrite, nickel, and glass is developed. There are a two-component developing method used as an agent and a one-component developing method using a developer consisting only of toner.

  Typical examples of the two-component development method include a cascade method described in US Pat. No. 2,618,552 (Patent Document 4) and a magnetic brush method described in US Pat. No. 2,874,063 (Patent Document 5). . In these methods, the carrier shares functions such as agitation, conveyance, and charging of the developer, and the functional separation between the carrier and the toner is clear. For this reason, toner charge control and developer layer formation are relatively easy and can be used at high speeds.

  Carriers using iron, ferrite, etc. have high resistance because of low resistance, but the reproducibility of fine lines is reduced, the chargeability of carriers due to toner spent on the carrier surface, and the carrier on the photoreceptor. There are problems such as image defects due to adhesion. On the other hand, in a carrier in which core material particles such as iron and ferrite are coated with a resin composition, the resin generally has a high resistance. Therefore, a carrier coated with the resin alone has a high resistance, and the electric field strength is increased during development. Since it is low, the edge effect is produced and the reproducibility of fine lines is improved, but a uniform image cannot be obtained or the image density is greatly reduced.

  Therefore, in order to prevent the carrier from having a high resistance, a carrier adjusted to an appropriate resistance by dispersing a conductive agent such as carbon black in the resin is generally used, and Japanese Patent Laid-Open No. 4-324457 (Patent Document) As shown in 6), a carrier in which the lower layer is coated with a conductive layer and the upper layer is coated with a high resistance layer, or as shown in JP-A-4-358168 (Patent Document 7), a resistance control agent is applied to the lower layer. A carrier in which a 0.5 to 1.0 μm thick resin layer is coated and an upper layer is coated with a 0.1 to 0.5 μm thick resin layer that does not contain a resistance control agent, or disclosed in JP-A-7-219281 (Patent Document 8). As described above, an insulating coating layer having a film thickness of 0.3 to 0.7 μm having a volume resistance in the range of 108 to 1011 Ωcm is formed as a first coating layer on the surface of the core particle, and a volume as a second coating layer is formed thereon. A conductive coating layer having a thickness of 0.05 to 0.4 μm having a resistance in the range of 1 to 104 Ωcm is formed. A carrier is proposed in which an insulating coating layer having a thickness of 0.5 to 1.0 μm having a volume resistance in the range of 108 to 1010 Ωcm is formed as a third coating layer. Further, JP-A 8-179570 (Patent Document 9) similarly proposes a carrier in which a carrier core material is coated with a resin layer containing carbon black and then a resin layer is provided on the surface.

  However, in these publications, since the surface is an insulating layer made of a resin that does not contain carbon black, the carrier has a high resistance, and as described above, the electric field strength is low when development is performed. It has not been sufficiently improved that an image cannot be obtained or that the image density is greatly reduced.

  In order to improve such defects, the carrier core material is coated with a resin layer having a uniform carbon black concentration from the vicinity of the carrier core material to the surface by containing an appropriate amount of carbon black in the coating resin of the carrier core material. Means for optimizing the resistance value have been conventionally devised. Certainly, according to this method, an appropriate carrier resistance value can be obtained in the initial stage of printing, and a developer having a high image density and a fine line reproducibility and having no edge effect can be obtained. The agitation in the step causes peeling of the resin layer, which is a coating agent for the carrier core material, and conversely, adhesion of a toner component to the carrier surface (hereinafter referred to as toner spent) causes a significant change in the surface state of the carrier. As a result, the resistance value of the carrier differs between the initial printing time and after long-time printing, and a printed matter with stable quality cannot be obtained.

  Particularly in recent years, the improvement of the printing speed exceeding 20 m / min has increased the stress caused by the stirring in the developing device, and in a situation where printing of a certain quality is required even for a long time operation, these A developer with sufficient performance that can satisfy the characteristics has not been obtained.

US Patent No. 2,297,691 Japanese Patent Publication No.42-023910 Japanese Patent Publication No. 43-024748 U.S. Pat. No. 2,618,552 U.S. Pat. No. 2,874,063 JP-A-4-324457 JP-A-4-358168 JP-A-7-219281 JP-A-8-179570

  An object of the present invention is to solve the above-described problems in a developer for developing an electrostatic image and an image forming method using the developer.

  That is, the present invention provides an electrostatic charge image developer that exhibits stable development and transfer performance without fluctuations in tribocharging performance and electrical resistance even when used as a two-component developer, and the electrostatic charge image developer. It is to provide an image forming method used.

  Another object of the present invention is to develop an electrostatic image that can achieve a high-quality and high-quality printed image free of background stains by rapidly reaching a predetermined charge amount when used as a two-component developer. And an image forming method using the developer.

  Another object of the present invention is to provide an electrostatic charge image developer exhibiting good tribocharging performance and electric resistance even during high-speed printing when used as a two-component developer, particularly at high-speed printing exceeding 20 m / min, and An object of the present invention is to provide an image forming method using the electrostatic charge image developer.

  As a result of intensive studies on various carriers, the present inventors have found that the above problems can be solved by a carrier having a specific resin coating layer.

That is, in order to solve the above problems, the present invention comprises an electrostatic charge image developing toner comprising a resin and a colorant, and a carrier having a resin layer containing a resistance control agent on the surface of the carrier core material. The resin layer has a resistance control agent concentration gradient in the thickness direction, the resistance control agent concentration is highest in the vicinity of the carrier core material, and decreases toward the surface of the resin layer, and further, the resistance on the surface of the resin layer. The present invention provides an electrostatic charge image developer characterized by the presence of a control agent, and an image forming method using the electrostatic charge image developer.
Further, the present invention comprises an electrostatic charge image developing toner containing a binder resin, a colorant and a charge control agent, and a carrier having a resin layer containing a resistance control agent made of carbon black on the surface of the carrier core material. An image forming method using an electrostatic charge image developer, wherein the resin of the resin layer is a silicone resin, and the resin layer is composed of two or more layers having different resistance control agent-containing concentrations, and resistance control is performed in the thickness direction. In the layer formed on the surface of the carrier core material, the resistance control agent concentration is highest in the layer formed on the surface of the carrier core, decreases toward the surface of the resin layer, and further on the surface of the uppermost layer of the resin layer. A layer containing 5 to 30% by weight of the resistance control agent on the surface of the carrier core material, and a layer containing 0.5 to 20% by weight of the resistance control agent in the uppermost layer 0.1 to 2.0 μm, In addition, the present invention provides an image forming method characterized in that a nigrosine dye and a quaternary ammonium salt compound are used in combination as the charge control agent, and the development speed is 20 m / min or more.

  That is, since the resistance control agent is present in the resin layer on the surface of the carrier, the resistance is slightly lower than that of the carrier coated with the resin alone layer. A print with high image quality is obtained. In addition, in printing for a long time, it is necessary to maintain a balance between low resistance due to the peeling of the resin layer on the carrier surface and exposure of the carrier core, and high resistance due to toner spent. The present inventors have found that the balance between the two can be maintained by using a carrier coated with a resin layer having a concentration gradient of the control agent.

  In the case where the carrier is subjected to a high degree of stress, the toner spent speed is faster than the peeling of the resin layer of the carrier, and therefore the speed of increasing the resistance is faster. By increasing the resistance control agent containing concentration as it approaches the carrier core material, the resin layer containing the resistance control agent at a high concentration is exposed each time a part of the resin layer surface is peeled off, thereby preventing the resistance from increasing. As a result, the resistance value of the carrier can be kept constant even during long-time printing. Such an action is particularly effective in a developing device having a developing speed of 20 m / min or more.

  The binder resin used in the present invention can be used without particular limitation as long as it is usually used as a binder resin in the toner. For example, polystyrene, styrene- (meth) An acrylic ester copolymer, an olefin resin, a polyester resin, an amide resin, a polycarbonate resin, an epoxy resin, and a graft polymer or a mixture thereof can be used.

  Among them, polyester resin, styrene- (meth) acrylic acid in consideration of charging stability, storage stability, fixing characteristics, or color reproducibility when used as a color toner resin containing chromatic organic pigments, etc. Ester copolymer resins can be suitably used.

  The polyester resin used in the present invention can be obtained, for example, by dehydrating and condensing dicarboxylic acid and diol by an ordinary method. Examples of the dicarboxylic acid include phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and cyclohexanedicarboxylic acid. Examples thereof include dicarboxylic acids such as acid, succinic acid, malonic acid, glutaric acid, azelaic acid, and sebacic acid, or derivatives thereof.

  Examples of the diol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, hexanediol, bisphenol A, and polyoxyethylene- (2.0) -2,2-bis. (4-hydroxyphenyl) propane and derivatives thereof, polyoxypropylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2 .0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2, 2-bis (4-hydroxyphenyl) propane, poly Oxypropylene- (2.4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.3) -2,2-bis (4-hydroxyphenyl) propane and its derivatives, etc. Can be mentioned.

  Furthermore, diols such as polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide random copolymer diol, ethylene oxide-propylene oxide block copolymer diol, ethylene oxide-tetrahydrofuran copolymer diol, polycaprocactone diol, etc. Can also be used.

  Further, if necessary, for example, a trifunctional or higher functional aromatic carboxylic acid such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride or a derivative thereof, or sorbitol, 1,2,3,6- Hexanetetraol, 1,4-sorbitan, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butane Triol, trimethylolethane, trimethylolpropane, 1,3,5-trimethylolbenzene or other trifunctional alcohol or more, or bisphenol A type epoxy resin, bisphenol F type epoxy resin, ethylene glycol diglycidyl ether, hydroquinone di Glycidyl ether, N, N-jig Cidylaniline, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, cresol novolac type epoxy resin, phenol novolac type epoxy resin, polymer of vinyl compound having epoxy group, Alternatively, a trifunctional or higher polyhydric epoxy compound such as a copolymer, an epoxidized resorcinol-acetone condensate, a partially epoxidized polybutadiene, or one or more of semi-dry or dry fatty acid ester epoxy compounds may be used in combination.

  The polyester resin in the present invention can be obtained by performing a dehydration condensation reaction or a transesterification reaction using the above raw material components in the presence of a catalyst. The reaction temperature and reaction time at this time are not particularly limited, but are usually 150 to 300 ° C. and 2 to 24 hours.

  As a catalyst for performing the above reaction, for example, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, or the like can be appropriately used.

  As the polyester resin used in the present invention, it is sufficient that it has an appropriate glass transition point and melt viscosity characteristics as a two-component developing toner, and a temperature at which the viscosity becomes 1 × 10 5 poise is 95 ° C. or more. Among them, the fixing temperature is preferably 95.degree. To 170.degree. C. because the fixing property at low temperature is good, and the temperature at which the viscosity is 1.times.10@5 poise is preferable. The thing of 95-160 degreeC is especially preferable.

  On the other hand, the glass transition temperature (Tg) is preferably 40 [deg.] C. or higher, and particularly preferably the glass transition temperature (Tg) is 45 to 85 [deg.] C. Further, the acid value is preferably 30 or less, and particularly preferably 10 or less. If the acid value is too high, the charge amount is lowered and the desired charge amount cannot be obtained.

Examples of the styrene monomer used in the styrene- (meth) acrylic acid ester copolymer resin used in the present invention include styrene, α-methylstyrene, vinyltoluene, p-sulfonestyrene, dimethylaminomethylstyrene, and the like. is there.

  Examples of (meth) acrylic acid ester monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. , Alkyl (meth) acrylates such as tertiary butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; fats such as cyclohexyl (meth) acrylate Cyclic (meth) acrylates; aromatic (meth) acrylates such as benzyl (meth) acrylate; hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate; (meth) acryloxyethylene Phosphoric acid group-containing (meth) acrylates such as ruphosphate; halogen atom-containing (meta) such as 2-chloroethyl (meth) acrylate, 2-hydroxy 3-chloropropyl (meth) acrylate and 2,3-dibromopropyl (meth) acrylate ) Acrylate; epoxy group-containing (meth) acrylate such as glycidyl (meth) acrylate; ether group-containing (meth) acrylate such as 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate; dimethylaminoethyl (meth) ) Acrylate, basic nitrogen atom such as diethylaminoethyl (meth) acrylate or amide group-containing (meth) acrylate;

  Moreover, the unsaturated compound copolymerizable with these can also be used as needed. For example, a carboxyl group-containing vinyl monomer such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid; a sulfo group-containing vinyl monomer such as sulfoethylacrylamide; a nitrile group-containing vinyl monomer such as (meth) acrylonitrile; Ketone group-containing vinyl monomers such as vinyl methyl ketone and vinyl isopropenyl ketone; basic such as N-vinyl imidazole, 1-vinyl pyrrole, 2-vinyl quinoline, 4-vinyl pyridine, N-vinyl 2-pyrrolidone, N-vinyl piperidone Nitrogen atom or amide group-containing vinyl monomers can be used.

  Moreover, you may use a crosslinking agent in the range of 0.1 to 2 weight% with respect to the said vinyl monomer. Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, divinyl ether, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1, 3-butylene glycol di (meth) acrylate, 1,6-hexane glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol Examples include di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and tetramethylolmethane tetra (meth) acrylate.

  Or in resin using the copolymer of the styrene- (meth) acrylic acid ester copolymerized with the said carboxyl group-containing vinyl monomer, it can also be set as crosslinked resin using a metal salt. As metal salts, halides such as Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Sn, Sr, Zn, hydroxide, oxide, carbonate, There are carboxylates, alkoxylates, chelate compounds and the like. The crosslinking reaction can be performed by heating and stirring in the presence of a solvent.

  As a method for producing a copolymer of styrene- (meth) acrylic acid ester, a usual polymerization method can be adopted, and a polymerization reaction is carried out in the presence of a polymerization catalyst such as solution polymerization, suspension polymerization, bulk polymerization and the like. Is mentioned.

  Examples of the polymerization catalyst include 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), Examples thereof include benzoyl peroxide, dibutyl peroxide, butyl peroxybenzoate, and the amount used is preferably 0.1 to 10.0% by weight of the vinyl monomer component.

  The styrene- (meth) acrylic acid ester copolymer resin used in the present invention may have an appropriate glass transition point and melt viscosity characteristics as a two-component developing toner, and its viscosity is 1 × 10 5. Those having a poise temperature of 95 ° C. or higher are preferable because of good fixability. Among them, those having a viscosity of 1 × 10 5 poise of 95 to 170 ° C. are more preferable because they have good fixability at low temperatures. A temperature of 95 to 160 ° C. at which the viscosity becomes 1 × 10 5 poise is particularly preferable.

  On the other hand, the glass transition temperature (Tg) of the copolymer resin of styrene- (meth) acrylic acid ester is preferably 40 ° C. or higher, and particularly preferably the Tg is 45 to 85 ° C.

  Further, the acid value is preferably 30 or less, and particularly preferably 15 or less. If the acid value is too high, the charge amount is lowered and the desired charge amount cannot be obtained.

  As the colorant, for example, carbon black, various organic pigments, inorganic pigments, dyes, and the like are used, and are not particularly limited, but examples thereof include the following.

  Examples of the colorant that can be used in the present invention include known ones. Carbon blacks such as furnace black, channel black, acetylene black, thermal black, lamp black, ketjen black and the like classified according to the production method are used as black colorants, and phthalocyanine-based C.I. I. Pigment Blue 15-3, Indanthrone C.I. I. Pigment Blue 60 and the like are quinacridone C.I. I. Pigment Red 122, an azo-based C.I. I. Pigment Red 22, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 48: 3, C.I. I. Pigment Red 57: 1 and the like are azo-based C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 155, an isoindolinone-based C.I. I. Pigment Yellow 110, a benzimidazolone-based C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185 and the like. The content of the colorant is in the range of 1 to 20 parts by weight. These colorants can be used alone or in combination of two or more.

  In the toner of the present invention, the weight ratio between the resin and the colorant is not particularly limited, but is usually 1 to 30 parts by weight, preferably 1 to 10 parts by weight per 100 parts by weight of the resin.

  In order to produce a color toner using the chromatic colorant, it is desirable to use a polyester resin from the viewpoint of excellent color image colorability and transparency. The polyester resin is more tough than the styrene acrylic resin, has a characteristic of resisting stress in the developing apparatus, and has a low melting point, and is suitable as a resin for color toner.

  As the positively chargeable charge control agent used in the present invention, a triphenylmethane dye, a nigrosine dye, a quaternary ammonium salt compound, a resin containing an amino group, and the like can be used. It is particularly desirable to use a quaternary ammonium salt compound in combination. The quaternary ammonium salt compound is particularly preferably at least one selected from compounds <general formula 1>, <general formula 2> or <general formula 3> having the following structure. Bontron P-51; (manufactured by Orient Chemical) is a compound having a structure of <general formula 1>, and TP-302, TP-415, TP-610; (manufactured by Hodogaya Chemical) is a compound of <general formula 2>. There is. <General formula 1>

［式中、Ｒ1〜Ｒ3はＣｎＨ２ｎ＋１基を表す。但し、ｎは１〜１０の整数を示す。また、Ｒ1〜Ｒ3は同じであっても異なっていてもよい。］
＜一般式２＞

[Wherein R1 to R3 represent a CnH2n + 1 group. However, n shows the integer of 1-10. R1 to R3 may be the same or different. ]
<General formula 2>

［式中、Ｒ1、Ｒ2、Ｒ3およびＲ4はそれぞれ独立に水素原子、炭素数１〜２２個のアルキル基あるいはアルケニル基、炭素数１〜２０個の未置換あるいは置換芳香族基、炭素数７〜２０個のアラルキル基を表し、Ａ-はモリブデン酸アニオンあるいはタングステン酸アニオン、モリブデンあるいはタングステン原子を含むヘテロポリ酸アニオンを表す。］
＜一般式３＞

[Wherein R 1, R 2, R 3 and R 4 are each independently a hydrogen atom, an alkyl or alkenyl group having 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having 1 to 20 carbon atoms, or 7 to 7 carbon atoms. 20 represents an aralkyl group, and A − represents a molybdate anion or a tungstate anion, or a heteropolyacid anion containing a molybdenum or tungsten atom. ]
<General formula 3>

［式中、ｍは１、２または３を示し、そしてｎは０、１または２を示し、Ｍは水素原子、または１価の金属イオンである。Ｘ及びＺは１または２を示し、Ｙは０または１を示す。さらに、Ｘ＝１の時、Ｙ＝１、Ｚ＝１となりＸ＝２の時、Ｙ＝０、Ｚ＝２となる。Ｒ5〜Ｒ12は水素、炭素数１〜30の直鎖状、あるいは枝分かれした飽和または不飽和のアルキル基、炭素数１〜４のアルコキシレン基、一般式（−Ｃ２〜５のアルキレン−Ｏ）ｎ−Ｒ（但し、Ｒは水素または炭素数１〜４のアルキル基またはアシル基であり、ｎは１〜１０の整数である）で表されるポリアルキルオキシレン基を表し、Ｒ1、Ｒ2、Ｒ3、Ｒ4は水素、または、炭素数１〜30の直鎖状、あるいは枝分かれした飽和または不飽和のアルキル基、または一般式（−ＣＨ2−ＣＨ2−Ｏ）ｎ−Ｒ（但し、Ｒは水素または炭素数１〜４のアルキル基またはアシル基であり、ｎは１〜１０の整数である）で表されるオキシエチル基、更に炭素数５〜12の単核−または多核脂環式残基、単核−または多核芳香族残基または芳香脂肪族残基を表す。］

[In the formula, m represents 1, 2 or 3, n represents 0, 1 or 2, and M represents a hydrogen atom or a monovalent metal ion. X and Z represent 1 or 2, and Y represents 0 or 1. Further, when X = 1, Y = 1 and Z = 1, and when X = 2, Y = 0 and Z = 2. R5 to R12 are hydrogen, a straight chain having 1 to 30 carbon atoms, or a branched saturated or unsaturated alkyl group, an alkoxylene group having 1 to 4 carbon atoms, and a general formula (-C2-5 alkylene-O) n. R represents a polyalkyloxylene group represented by -R (wherein R is hydrogen, an alkyl group having 1 to 4 carbon atoms or an acyl group, and n is an integer of 1 to 10), R1, R2, R3 , R4 is hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, or a general formula (-CH2-CH2-O) n-R (where R is hydrogen or carbon An oxyethyl group represented by an alkyl group or an acyl group of 1 to 4 and n is an integer of 1 to 10), a mononuclear or polynuclear alicyclic residue having 5 to 12 carbon atoms, a mononuclear -Or a polynuclear aromatic residue or an araliphatic residue. ]

More specifically, there are the following compounds.
(1-1)

（２−１）

(2-1)

（２−２）

(2-2)

（２−３）

(2-3)

（２−４）

(2-4)

（２−５）

(2-5)

（２−６）

(2-6)

（２−７）

(2-7)

（２−８）

(2-8)

（２−９）

(2-9)

（２−１０）

(2-10)

（２−１１）

(2-11)

（３−１）

(3-1)

（３−２）

(3-2)

  When the nigrosine dye and the quaternary ammonium salt compound are used in combination, the use ratio is preferably 1/9 to 9/1, and more preferably 2/8 to 8/2. Nigrosine-based dyes have a high ability to impart positive charge, but are inferior in charge uniformity and stability, and when used alone, fogging is likely to occur, resulting in a printed image with insufficient sharpness. Quaternary ammonium salt compounds are excellent in charge uniformity and stability, but have a low ability to impart positive charge, and when used in combination with a nigrosine dye rather than being used alone, clear printing without fog during continuous printing. Images can be obtained stably. When the use ratio of the nigrosine dye is lower than 1, the toner cannot be sufficiently charged, and the transfer efficiency to the paper is lowered. As a result, the image is inferior in the uniformity of the solid portion and the resolution of the image line. In addition, toner scattering increases due to the low charge. When the use ratio is more than 9, the charge amount becomes too high, and the developer has low density and low image quality with a lot of fog in continuous printing.

  As described above, when either one is too much or too little, an optimum charge amount cannot be obtained, and as a result, a printed matter with low density and low image quality is obtained, and a developer in which toner scattering occurs. By adjusting the ratio between the two, an optimum charge amount can be obtained, and there is no fogging, high-density and high-quality printing with clear image contours, and long-life developer without toner scattering. Obtainable.

  The content of the charge control agent is preferably 0.3 to 10 parts by weight, more preferably 1 to 5 parts by weight per 100 parts by weight of the binder resin.

  Further, in heat roll fixing applications, various waxes are used as needed as an auxiliary agent for enhancing the release effect for the purpose of preventing troubles caused by toner heat roll adhesion contamination (offset). Such natural waxes, high-pressure polyethylene, and polyolefin waxes such as polypropylene can be used.

  Among these, in the present invention, it is particularly preferable to use carnauba wax, montan ester wax, rice wax and / or scale insect wax. These waxes exhibit the best dispersibility in the polyester resin having the structure according to the present invention, and the improvement in fixing property and offset resistance is remarkable.

  As the carnauba wax, it is preferable to use a free fatty acid type carnauba wax from which free fatty acids have been removed by purification. The acid value of the de-free fatty acid type carnauba wax is preferably 8 or less, more preferably 5 or less. The de-free fatty acid type carnauba wax becomes microcrystalline than the conventional carnauba wax and the dispersibility in the polyester resin is improved. The montan ester wax is refined from minerals, and by refining, it becomes microcrystals similar to carnauba wax and the dispersibility in the polyester resin is improved. In the case of montan ester wax, the acid value is particularly preferably 30 or less.

  The rice wax is obtained by purifying rice bran wax, and the acid value is preferably 13 or less. The scale insect wax can be obtained by, for example, dissolving a waxy component secreted by a scale larva of a scale insect (also known as scallop) in hot water, separating the upper layer and cooling and solidifying, or repeating the process. The scale insect wax purified by such means is white in the solid state and exhibits an extremely sharp melting point, which is suitable as a toner wax in the present invention. The acid value is 10 or less by purification, and 5 or less is preferable for toner.

The above waxes may be used alone or in combination. Good fixing offset performance can be obtained by adding 0.3 to 15 parts by weight, preferably 1 to 5 parts by weight, with respect to the binder resin. If the amount is less than 0.3 parts by weight, the offset resistance is impaired. If the amount is more than 15 parts by weight, the fluidity of the toner deteriorates, and the spent carrier is generated by adhering to the carrier surface, which adversely affects the charging characteristics of the toner. Will give.

  In addition to the above natural waxes, synthetic ester waxes can also be suitably used. Synthetic ester waxes include pentaerythritol tetrabehenate. Synthetic waxes such as polypropylene wax and polyethylene wax can also be used in combination.

  The toner of the present invention can be obtained by a very general production method regardless of a specific production method. For example, after melt-kneading a resin and a colorant at a melting point (softening point) or higher of the resin, It can be obtained by pulverization and classification.

  Specifically, for example, the resin and the colorant are mixed as essential components by a kneading means such as a two-roll, three-roll, pressure kneader, or twin-screw extruder. At this time, the colorant only needs to be uniformly dispersed in the resin, and the melt kneading conditions are not particularly limited, but are usually 80 to 180 ° C. for 30 seconds to 2 hours. As the colorant, a masterbatch that is previously flushed so as to be uniformly dispersed in the resin or melt-kneaded with the resin at a high concentration may be used.

  Then, after cooling it, a method of pulverizing with a pulverizer such as a jet mill and classifying with an air classifier or the like can be mentioned.

  The average particle diameter of the particles constituting the toner base is not particularly limited, but is usually adjusted to 5 to 15 μm.

  Usually, an external additive is mixed with the toner base thus obtained using a mixer such as a Henschel mixer.

  External additives are used for surface modification of a toner base such as improvement of toner fluidity and charging characteristics, and include inorganic fine powders such as silicon dioxide, titanium oxide, and alumina, and hydrophobic substances such as silicone oil. A surface treated with a chemical treatment agent, a resin fine powder, or the like is used.

Examples of silica include those having hydrophobicity among silicon dioxide, and those obtained by surface-treating silicon dioxide with various polyorganosiloxanes and silane coupling agents. For example, there are those marketed under the following trade names.
AEROSIL R972, R974, R202, R805, R812
RX200, RY200, R809, RX50,
RA200HS, RA200H [Nippon Aerosil Co., Ltd.]
WACKER HDK, H2000, H2050EP,
HDK H3050EP, HVK2150
[Wacker Chemicals East Asia Co., Ltd.]
Nipsil SS-10, SS-15, SS-20, SS-50,
SS-60, SS-100, SS-50B, SS-50F,
SS-10F, SS-40, SS-70, SS-72F
[Nippon Silica Industry Co., Ltd.]
CABOSIL TG820F [Cabot Specialty Chemicals, Inc.]
The use ratio of the external additive is usually 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the toner base.

  These silicas may be used in combination of two or more of different average particle sizes. The proportion of silica used is usually 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the toner base.

  The electrostatic charge image developer of the present invention has a toner containing colored resin particles and a resin layer containing a resistance control agent on the surface of the carrier core, and the resin layer has a concentration gradient of the resistance control agent in its thickness direction. In the vicinity of the carrier core material, the resistance control agent concentration is the highest, decreases toward the surface of the resin layer, and further comprises a magnetic carrier in which the resistance control agent is present on the surface of the resin layer.

  The core agent of the carrier used in the present invention can be iron powder, magnetite, ferrite, etc. used in the usual two-component development method, but the true specific gravity is low, the resistance is high, the environmental stability is excellent, and the spherical shape is made. Since it is easy, ferrite or magnetite having good fluidity is preferably used. The shape of the core agent can be used without any problem, such as a spherical shape or an indefinite shape. The average particle diameter is generally 10 to 500 μm, but 30 to 80 μm is preferable for printing a high resolution image.

  Examples of the coating resin for coating these core agents include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether polyvinyl ketone, vinyl chloride / vinyl acetate. Copolymers, styrene / acrylic copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluorine resins, (meth) acrylic resins, polyesters, polyurethanes, polycarbonates, phenol resins, amino resins, melamine resins, benzoguanamine resins Urea resin, amide resin, epoxy resin and the like can be used. Among these, silicon resin, fluororesin, and (meth) acrylic resin are particularly excellent in charging stability and coating strength, and can be used more suitably. That is, the resin-coated carrier used in the present invention is a resin-coated magnetic carrier in which ferrite or magnetite is used as a core agent and is coated with one or more kinds of resins selected from silicone resins, fluororesins, and (meth) acrylic resins. It is preferable. A silicone resin is particularly preferable as the coating resin.

  As the resistance control agent dispersed in the resin, carbon black such as acetylene black, channel black, furnace black, ketjen black, metal carbide such as SiC, TiC, metal nitride such as BN, NbN, TiN, Metal borides such as MoB, CrB, and TiB2, metal oxides such as ZnO, PiO2, and SnO2, and metal fine powders such as Al and Ni can be used. The number average diameter of the resistance control agent is 0.01 to 5 μm, preferably about 0.05 to 3 μm. This is measured with a transmission electron microscope.

  Among these, carbon black is particularly preferable, and carbon black having a DBP oil absorption of 300 cm 3/100 g or more is most preferable. As such examples, Ketjen Black EC and Ketjen Black EC600JD (manufactured by Ketjen Black International) are commercially available.

  Further, the carrier used in the present invention has a resin layer containing a resistance control agent on the surface of the carrier core material, the resin layer has a concentration gradient of the resistance control agent in the thickness direction thereof, and has a resistance near the carrier core material. Although the concentration of the control agent is the highest, it becomes lower toward the surface of the resin layer, and the resistance control agent is present on the surface of the resin layer, but the concentration gradient of the resistance control agent in the thickness direction of the resin layer There is no particular limitation as to the method of providing the.

  As a preferred method, a resin layer containing 5 wt% to 30 wt% of a resistance control agent is provided on the surface of the carrier core material so as to have a thickness of 0.1 μm to 2.0 μm, and the resistance control agent concentration is gradually decreased. In this method, an adjusted resin layer is provided, and a resin layer containing 0.5 wt% to 20 wt% of the resistance control agent is provided on the uppermost layer so as to have a thickness of 0.1 μm to 2.0 μm. The number of resin layers is most preferably 2 to 4 layers. The thickness of the entire coating layer on the carrier surface is usually 0.1 to 5.0 μm.

  The method of coating the resin containing the resistance control agent on the surface of the carrier core material is not particularly selected, but the dipping method of immersing in the solution of the coating resin containing the resistance control agent, the coating resin solution on the surface of the carrier core material Examples thereof include a spraying method for spraying, a fluidized bed method in which the carrier is sprayed in a state where the carrier is suspended by flowing air, and a kneader coater method in which the carrier core material and the coating resin solution are mixed in a kneader coater to remove the solvent.

  The solvent used in the coating resin solution is not particularly limited as long as it dissolves the coating resin. For example, toluene, xylene, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane and the like can be used.

  The weight ratio between the toner containing the colored resin particles and the resin-coated magnetic carrier is not particularly limited, but is usually 0.5 to 15 parts by weight per 100 parts by weight of the carrier.

   EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited to these. In the following Examples and Comparative Examples, “%” represents “% by weight” unless otherwise specified.

(Resin synthesis example 1)
2.0 mol parts of terephthalic acid
2.5 parts by mole of isophthalic acid
Trimellitic acid 0.5 mol part
Polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane 4.0 mol parts ethylene glycol 1.2 mol parts
Into a four-necked flask equipped with a stirrer, condenser and thermometer, add 0.07 parts by weight of dibutyltin oxide to the total acid component under a nitrogen gas stream, and remove the water produced by dehydration condensation. The reaction was carried out at 220 ° C. for 15 hours. The obtained polyester resin had a softening temperature of 155 ° C. by a ring and ball softening point measurement method, a Tg of 62 ° C. by an DSC method, and an acid value of 10.

(Resin synthesis example 2)
A polyester resin of Resin Synthesis Example 2 was produced in the same manner as in Resin Synthesis Example 1 using the following raw materials.
Terephthalic acid 2.5 mol part Isophthalic acid 2.5 mol part Trimethylolpropane 0.5 mol part Polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane 3.5 mol part Ethylene Glycol 1.0 mol part
The resulting resin had a softening temperature of 150 ° C. according to the ring and ball softening point measurement method, a Tg of 61 ° C. and an acid value of 6 according to the DSC method.

(Resin synthesis example 3)
Styrene 320 parts by weight Butyl acrylate 60 parts by weight Methacrylic acid 20 parts by weight Azobisisobutyronitrile 4 parts by weight Xylene 600 parts by weight

  Was put in a round bottom flask and reacted in a nitrogen gas atmosphere at 80 ° C. for about 10 hours, and then heated to 130 ° C. to complete the polymerization. Thereafter, 12 parts by weight of aluminum isopropoxide was added and allowed to react for about 1 hour, and then the mixture was heated to 180 ° C. and depressurized to 0.5 mmHg with a vacuum pump to remove the solvent.

  The resulting chelate-crosslinked styrene acrylic resin had a softening temperature of 145 ° C. by a ring and ball softening point measurement method, a Tg of 61 ° C. by an DSC method, and an acid value of 5.

(Toner Example 1)
Resin of resin synthesis example 1 92 parts by weight Carbon black 5 parts by weight “Mogal L (manufactured by Cabot Specialty Chemicals, Inc.)”
Biscol 550P (manufactured by Sanyo Chemical) 2 parts by weight Charge control agent (positive charge control agent)
"Bontron N-07 (produced by Orient Chemical Co., Ltd.)" 1.5 parts by weight "Quaternary ammonium salt compound (2-1)" 1.5 parts by weight are mixed with a Henschel mixer and kneaded with a twin-screw kneader. To do. The kneaded material thus obtained was pulverized and classified to obtain “toner base A” having a volume average particle size of 10.1 microns.

-"Toner base A" 100 parts by weight-Silica HDK3050EP (Wacker Chemicals) 1 part by weight was mixed with a Henschel mixer, and toner A was obtained through a sieve.

(Toner Example 2)
Resin of resin synthesis example 3 92 parts by weight Carbon black 5 parts by weight “Mogar L (manufactured by Cabot Specialty Chemicals, Inc.)
Biscol 550P (manufactured by Sanyo Chemical Co., Ltd.) 2 parts by weight Charge control agent (positive charge control agent)
"Bontron N-07 (produced by Orient Chemical Co., Ltd.)" 1.5 parts by weight "Quaternary ammonium salt compound (3-1)" 1.5 parts by weight are mixed with a Henschel mixer and kneaded with a twin-screw kneader. To do. The kneaded material thus obtained was pulverized and classified to obtain “toner base B” having a volume average particle size of 10.1 microns.

-"Toner base B" 100 parts by weight-Silica HDK3050EP (Wacker Chemicals) 1 part by weight was mixed with a Henschel mixer, and then toner B was obtained through a sieve.

(Carrier Example 1)
To 10000 parts of ferrite particles having an average particle diameter of 100 μm, 13 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) is mixed with 400 parts of a silicone-based resin (Toray Silicon SR2410: solid content 20%). Fluidized-bed spray coating, immediately mixing 2 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) with 100 parts of silicone resin (Toray Silicon SR2410: solid content 20%) Layer-type spray coating was performed, and this was baked at 250 ° C. for 2 hours to obtain Carrier C.

(Carrier Example 2)
To 10000 parts of ferrite particles having an average particle size of 100 μm, 12 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) is mixed with 350 parts of silicone resin (Toray Silicon SR2410: solid content 20%). Then, fluidized bed spray coating was performed, and immediately 2.5 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) was mixed with 100 parts of silicone resin (Toray Silicon SR2410: solid content 20%). Immediately after fluidized bed spray coating, carbon black (Ketzen Black EC600DJ (Ketjen Black International) is applied to 50 parts of silicone resin (Toray Silicon SR2410: solid content 20%). Ltd.)) 1 part were mixed and fluidized bed spray coating, this was subject to seizure 2 hours at 250 °, to obtain a carrier D.

(Carrier Example 3)
To 10000 parts of ferrite particles having an average particle diameter of 100 μm, 17 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) is mixed with 400 parts of a silicone-based resin (Toray Silicon SR2410: solid content 20%). Then, fluidized bed spray coating was performed, and 1.7 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) was immediately mixed with 100 parts of silicone resin (Toray Silicon SR2410: solid content 20%). Then, fluidized bed spray coating was performed, and this was baked at 210 ° C. for 2 hours to obtain Carrier E.

(Carrier Comparative Example 1)
To 10000 parts of ferrite particles having an average particle diameter of 100 μm, 10 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) is mixed with 500 parts of silicone resin (Toray Silicon SR2410: solid content 20%). Then, fluidized bed spray coating was performed, and this was baked at 250 ° C. for 2 hours to obtain Carrier F.

(Carrier Comparative Example 2)
Carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) 16.3 parts to 10000 parts of ferrite particles having an average particle size of 100 μm and 500 parts of silicone resin (SR2410: 20% solid content). The mixture was mixed and fluidized-bed spray coated, and this was baked at 250 ° C. for 2 hours to obtain carrier G.

(Carrier Comparative Example 3)
To 10,000 parts of ferrite particles having an average particle size of 100 μm, 8.5 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) is added to 500 parts of silicone resin (Toray Silicon SR2410: solid content 20%). This was mixed and fluidized-bed spray coated, and this was baked at 210 degrees for 2 hours to obtain carrier H.

(Carrier Comparative Example 4)
To 10000 parts of ferrite particles having an average particle diameter of 100 μm, 13 parts of carbon black (Ketzen Black EC600DJ (Ketjen Black International Co., Ltd.)) is mixed with 400 parts of a silicone-based resin (Toray Silicon SR2410: solid content 20%). , Fluidized bed spray coating, immediately mixed with 100 parts of silicone resin (Toray Silicon SR2410: solid content 20%), fluidized bed spray coated, baked at 250 degrees for 2 hours, carrier I Obtained.

<Adjustment of developer>
-Toner A 5 parts by weight-Carrier C (silicone resin-coated ferrite carrier) 95 parts by weight were mixed and stirred to prepare "Developer Example 1".

  In the same manner, Examples 1 to 3 and Comparative Examples 1 to 4 were produced in the same manner as shown in Table 1.

  For the developers obtained in the above Examples and Comparative Examples, printing tests were performed as follows.

  (Printing test) Using a commercially available laser beam printer (with a selenium photosensitive member: development speed of 20 m / min), the print quality by continuous printing was evaluated, and the charge amount of the developer was measured. The charge amount was measured with a blow-off charge amount measuring machine. The image density was measured with a Macbeth densitometer RD-918, and the background stain was determined by subtracting the density of the white paper before printing from the density of the white background.

The above evaluation results are shown in Table 2.
Table 2. Evaluation results

The display in the table is as follows.
* “Charge”: μC / g
* "Soil dirt evaluation" ○: Less than 0.01, △: Less than 0.01 to 0.03, La: 0.03 or more

  As is apparent from Table 2, the toner comprises an electrostatic charge image toner comprising a resin and a colorant according to the present invention and a carrier having a resin layer containing a resistance control agent on the surface of the carrier core material. An electrostatic charge image characterized by having a concentration gradient of the resistance control agent in the thickness direction, the resistance control agent concentration decreasing toward the surface of the resin layer, and the resistance control agent being present on the surface of the resin layer. The developer has a constant charge amount and image density in the printing durability test, and has little background stain.

Claims (5)

An electrostatic charge image developer comprising: an electrostatic charge image developing toner containing a binder resin, a colorant, and a charge control agent; and a carrier having a resin layer containing a resistance control agent comprising carbon black on the surface of the carrier core material. The resin layer resin is a silicone resin, and the resin layer is composed of two or more layers having different resistance control agent-containing concentrations, and the concentration gradient of the resistance control agent in the thickness direction thereof. The resistance control agent concentration is highest in the layer formed on the surface of the carrier core material, and decreases toward the surface of the resin layer, and the resistance control agent is present on the surface of the uppermost layer of the resin layer. A 0.1 to 2.0 μm layer containing 5 to 30% by weight of the resistance control agent is provided on the surface of the carrier core material, and a layer containing 0.5 to 20% by weight of the resistance control agent is provided in the uppermost layer. ~ 2.0μm and the charging system An image forming method, wherein a nigrosine dye and a quaternary ammonium salt compound are used in combination as a control agent, and the development speed is 20 m / min or more. The image forming method according to claim 1, wherein the colorant of the toner for developing an electrostatic image is carbon black. The image forming method according to claim 1, wherein the toner for developing an electrostatic charge image contains 0.3 to 15 parts by weight of wax with respect to the binder resin. The image forming method according to claim 1, wherein the binder resin used in the electrostatic image developing toner is a polyester resin. The image forming method according to claim 1, wherein the binder resin used for the electrostatic image developing toner is a styrene- (meth) acrylic ester copolymer resin.