JP4103517B2 - Electrostatic latent image developing carrier, electrostatic latent image developer, and image forming method - Google Patents

Description

【０１２０】
（実施例１〜３、比較例１〜６）
トナーとして前記外添トナーａまたはｂを用いた現像剤１〜９を、高温高湿環境（２８℃、８０ＲＨ％）と低温低湿環境（１０℃、１５ＲＨ％）とにそれぞれ一昼夜放置した後、富士ゼロックス社製Ａカラー９３６の現像器に適用し、それぞれの環境下で５０，０００枚画像出しを行い、初期（１枚目）と、５０，０００枚目について画像サンプルの画質評価と帯電性評価とを行った。
【０１２１】
なお、上記帯電性評価は、ブローオフ法によるトナー帯電量の測定によって行い、画質評価は、主にカブリについて目視評価を行った。評価基準は以下の通りである。
【０１２２】
−画質評価基準−
◎：カブリが全くなく、非常に良好。
○：カブリが多少あるが、実用上問題なし。
△：カブリがやや多く、実用上問題あり。
×：カブリが目立つ。
結果を表２に示す。なお、表２中、被膜剥離は走査型電子顕微鏡を用いてキャリア表面を観察することにより確認した。
【０１２３】
【表２】

【０１２４】
表２の結果から明らかなように、実施例１〜３の本発明の静電潜像現像用キャリアを用いた現像剤では、高温高湿環境及び低温低湿環境における初期のトナー帯電性及び画質はいずれも非常に良好であり、５０，０００枚目時のトナー帯電性及び画質も良好であった。
【０１２５】
一方、比較例１の現像剤は、高温高湿環境及び低温低湿環境における初期のトナー帯電性及び画質はいずれも良好であったが、高温高湿環境における５０，０００枚目時のトナー帯電量が低下し、キャリア表面にトナー汚染が認められ、画像にカブリが認められた。比較例２の現像剤は、低温低湿環境における初期のトナー帯電性及び画質はほぼ良好であったが、高温高湿環境における初期のトナー帯電量が低下し、画質はやや悪いものであった。５０，０００枚目時にはキャリアの被覆樹脂が剥離し、キャリア飛散が認められた。
【０１２６】
比較例３の現像剤は、初期、５０，０００枚目時のトナー帯電性及び画質は悪くはないが、比較例１よりは発生時期は遅いもののトナー飛散が生じた。高温高湿環境及び低温低湿環境における５０，０００枚目時のトナー帯電量、画質にも実用上やや問題が生じた。比較例４の現像剤は、比較例３以上のトナー帯電性及び画質を示したが、高温高湿環境における５０，０００枚目時のトナー帯電量、画質に実用上問題があった。
【０１２７】
比較例５の現像剤は、初期のトナー帯電性画質は悪くないが、高温高湿環境における５０，０００枚目時のトナー帯電性及び画質が低下し、低温低湿環境でも実用上問題が生じた。
【０１２８】
【発明の効果】
本発明によれば、帯電性、帯電付与維持性、環境安定性、耐久性、耐汚染性に優れた静電潜像現像用キャリア及びそれを用いた現像剤を提供することができ、高画質の画像を形成し得る画像形成方法をも提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic latent image developing carrier used in an electrophotographic process and an electrostatic recording process, an electrostatic latent image developer, and an image forming method.
[0002]
[Prior art]
In the electrophotographic process, an electrostatic latent image is formed on the surface of a photosensitive member or electrostatic recording member by using various means, and charged fine particles called toner are attached to the electrostatic latent image. Conventionally, a method for developing an image has been generally used. In this method, carrier particles (magnetic particles) called carriers are mixed with toner, both are frictionally charged with each other, and an appropriate amount of positive or negative charge is imparted to the toner to thereby remove the toner. It is attached to the electrostatic latent image.
[0003]
The carrier is generally classified into a coated carrier having a coating layer on the surface and an uncoated carrier having no coating layer on the surface. Since the carrier is superior, various coated carriers have been developed and put into practical use.
[0004]
The coated carrier is required to have an appropriate chargeability (charge amount and charge distribution) to the toner and to maintain the chargeability for a long period of time. For this purpose, the impact resistance of the carrier is required. In addition, it is required that the chargeability of the toner is not changed even with respect to wear resistance and environmental changes such as humidity and temperature, and various coated carriers have been proposed.
[0005]
As the cause of carrier deterioration, the following two are considered conventionally.
One is fixing of the toner component to the surface of the carrier coating resin. That is, when toner or an external additive having a polarity opposite to that of the carrier adheres to the surface of the carrier coating resin, the charge imparting ability of the carrier is lowered. Further, the adhesion of the insulating toner increases the resistance of the carrier.
[0006]
Furthermore, peeling of the coating resin due to stress over time can be mentioned. That is, when the amount of the coating resin on the carrier surface decreases, the charge imparting ability decreases, and when the core material (core material) is exposed, the charge imparting ability similarly decreases, and the resistance of the carrier also decreases.
[0007]
In response to these problems, the surface energy of the coating resin is reduced using fluorine resin, silicone resin, etc. to prevent the carrier surface from being contaminated, and the strength of the coating resin is improved to prevent peeling or chipping of the coating resin. Has been proposed. However, the low surface energy material has poor adhesion to the core material, and it has been difficult to simultaneously provide the stain resistance and peel resistance of the coating resin.
[0008]
Therefore, a carrier coated with a copolymer of a (meth) acrylic acid ester monomer and a monomer having a carboxyl group has been proposed for the purpose of improving the adhesion imparting property by improving the adhesion of the coating resin. (For example, see Patent Document 1). The carboxyl group used here is effective for improving the negative chargeability imparting ability of the carrier and improving the durability by improving the adhesion with a core material such as a metal. Since the carboxyl group, which is a functional group, is exposed and exhibits hygroscopicity, there is a drawback in that the ability to impart charge is reduced and the product is easily contaminated.
[0009]
Also, the carrier core material (core material) surface has a copolymer of nitrogen-containing fluorinated alkyl (meth) acrylate and vinyl monomer, or a copolymer of fluorinated alkyl (meth) acrylate and nitrogen-containing vinyl monomer. For example, patent documents 2 to 4 have been proposed which are coated with a toner and are not easily contaminated with toner and external additives and have a relatively long life. However, the above-mentioned fluororesins have poor charge-imparting ability. For example, copolymerization of a nitrogen-containing vinyl monomer having a highly charged polar group or a methyl methacrylate monomer has a problem that the environmental dependency deteriorates. .
[0010]
Therefore, in order to solve the problem of deterioration of the environmental dependency, a carrier coated with a methacrylic acid cycloalkyl ester polymer excellent in moisture resistance has been proposed by paying attention to a methacrylic acid ester monomer (see, for example, Patent Document 5). ). However, since this carrier has a lower charge level than a carrier coated with a methylmethacrylic acid polymer and is brittle, it has problems such as poor adhesion to the core material.
[0011]
In order to improve this, a carrier coated with a copolymer of methacrylic acid cycloalkyl ester and methyl methacrylic acid has been proposed (for example, see Patent Document 6). However, since the cycloalkyl ester is brittle, it is easy to peel off. When the composition ratio of methyl methacrylic acid is increased, the environmental dependency deteriorates, and it is difficult to achieve both durability and environmental dependency.
[0012]
Moreover, although the carrier which coat | covered the copolymer containing the tertiary butyl acrylate component and the methyl acrylate component is proposed (patent document 7), these (meth) acrylic acid ester seed | species is contained 2 or more types. Therefore, it is easier to control charge imparting characteristics than a coated carrier using a homopolymer alone. However, as in the case of using a cycloalkyl ester, the adhesiveness with the core material is lowered and becomes brittle, so that the durability is inferior and there is a problem in the charge-maintaining property.
As described above, it has been extremely difficult to satisfy simultaneously the charge level, the charge-maintaining property, the environment dependency, the contamination resistance, and the durability, which are requirements for carrier reliability.
[0013]
On the other hand, with respect to the surface of the coating resin layer, a carrier that defines the surface F / N ratio (fluorine atom / nitrogen atom ratio) has been proposed (see, for example, Patent Document 8). By setting the surface of the coating resin layer to a certain range of F / N ratio, the coating resin layer can be improved in the spent resistance and the charge imparting ability to the toner, and the charging property is stable and good with no change over time. A state image can be formed. However, even when the surface of the coating resin layer is maintained within a certain range of F / N ratio, the dispersion is non-uniform at the atomic level, and the toner has a uniform chargeability, a spent resistance, and a charge-maintaining property. To improve, further uniform dispersion is required.
[0014]
As another improvement means, a number of lightweight carriers in which magnetic powder is dispersed in a resin have been proposed. For example, a magnetic powder-dispersed spherical carrier is obtained by melting and mixing magnetic powder in a polyolefin resin and spray cooling. Has been proposed (see, for example, Patent Document 9). However, although this carrier is effective in preventing toner contamination on the carrier surface, the charge imparting ability is not sufficient, so that charging failure of the replenishment toner cannot be improved.
[0015]
In addition, a method has been proposed in which a functional material such as an amino resin is mixed with a polymerizable monomer and magnetic powder, and suspension polymerization is performed to form a carrier (see, for example, Patent Documents 10 and 11). Although these carriers have a high amino resin concentration on the surface side from the center and are effective in improving the charging failure of the replenishment toner by improving the charge rising speed, they can sufficiently prevent toner contamination on the carrier surface. I can't do it and I'm not satisfied. Furthermore, the carrier in which such a functional material has a concentration gradient is liable to change in surface composition due to wear of the carrier surface, and causes deterioration of charging.
[0016]
Furthermore, a method has been proposed in which amino resin powder having a vinyl group introduced on the surface, vinyl monomer and magnetic powder are mixed and subjected to suspension polymerization to form a carrier (for example, see Patent Document 12). Although this carrier is effective in improving the charging failure of the replenishment toner by increasing the charge rising speed, it is not satisfactory because toner contamination on the carrier surface cannot be prevented.
[0017]
[Patent Document 1]
JP-A-2-114271
[Patent Document 2]
JP 61-80161 A
[Patent Document 3]
JP 61-80161 A
[Patent Document 4]
JP 61-80163 A
[Patent Document 5]
JP 59-104664 A
[Patent Document 6]
JP-A-7-114219
[Patent Document 7]
JP 60-66264 A
[Patent Document 8]
JP 9-319157 A
[Patent Document 9]
Japanese Patent Publication No. 7-46236
[Patent Document 10]
JP-A-5-197209
[Patent Document 11]
Japanese Patent Laid-Open No. 5-197210
[Patent Document 12]
JP 7-46236 A
[0018]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, the present invention provides a carrier for developing an electrostatic latent image having excellent chargeability, charge retention, environmental stability, durability, and stain resistance, a developer using the carrier, and a high-quality image. An object of the present invention is to provide an image forming method that can be formed.
[0019]
[Means for Solving the Problems]
  The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> A carrier for developing an electrostatic latent image having a resin on the surface, the fluorine atom-containing resin andLiquidThe resin is swollen by contacting with a medium containing a dispersion medium, and after the fluorine atom-containing resin has entered the resin, the dispersion medium is removed to disperse the fluorine atom-containing resin in the resin. This is a carrier for developing an electrostatic latent image.
[0020]
<2> An electrostatic latent image developer containing a toner and a carrier, wherein the carrier is the electrostatic latent image developing carrier according to <1>. is there.
[0021]
<3> The electrostatic latent image developer according to <2>, wherein the toner contains a carboxyl group-containing monomer in a binder resin.
[0022]
<4> The electrostatic latent image developer according to <2>, wherein the toner is produced by a wet method.
[0023]
<5> A step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on the surface of the developer carrier to form a toner image, An image forming method comprising a transfer step of forming a transfer image by transferring to a surface of a recording material, and a fixing step of fixing the transfer image transferred to the surface of the recording material, wherein the developer is <2> to <4> An image forming method comprising the electrostatic latent image developer according to any one of <4>.
[0024]
The present inventors have made a carrier produced by a method of swelling a resin on the surface of a carrier and incorporating a fluorine atom-containing resin, that is, a carrier having a uniform surface composition, low surface energy, and improved material adhesion. By using the carrier for electrostatic latent image development, the toner is uniformly charged, the toner and external additives are less likely to adhere to the surface, the surface containing the fluorine atom-containing resin is less worn, and the charge imparting maintenance is excellent. Made it possible to provide Further, by using a specific toner for the carrier, it is possible to further improve the uniform chargeability and the charge-maintaining property, thereby enabling high-quality image formation.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described in detail.
<< Carrier for electrostatic latent image development >>
  The carrier for developing an electrostatic latent image of the present invention is a carrier for developing an electrostatic latent image having a resin on the surface, the fluorine atom-containing resin andLiquidThe resin is swollen by contact with a medium containing a dispersion medium, and after the fluorine atom-containing resin has entered the resin, the dispersion medium is removed to leave the fluorine atom-containing resin in the resin. It is characterized by that.
[0026]
As the electrostatic latent image developing carrier having a resin on the surface, there are a resin-coated carrier and a resin carrier.
<Resin coated carrier>
The resin-coated carrier used in the present invention is a carrier obtained by coating the surface of a core material with a coating resin layer.
−Core material−
The core material is a core of the carrier, and the material thereof is not particularly limited. For example, magnetic metal such as iron, steel, nickel and cobalt, magnetic oxide such as ferrite and magnetite, and glass beads And so on. Among these, when the magnetic brush method is adopted for development, it is preferable to use a magnetic material.
[0027]
The volume average particle diameter of the core material is preferably in the range of 10 to 150 μm, and more preferably in the range of 20 to 100 μm. The true specific gravity of the core material is 4-6 g / cm.^ThreeThe range of the degree.
[0028]
As another carrier core material used in the present invention, a spherical core (magnetic powder-dispersed core) in which magnetic powder is dispersed in a resin can be exemplified. Since this spherical core has a small specific gravity, there is an advantage that it is possible to suppress stress on the toner and carrier, and in combination with a coating resin layer, which will be described later, it is effective in securing charge imparting maintenance and environmental stability. .
[0029]
Examples of the resin used for the magnetic powder-dispersed core include cross-linked resins such as phenol resins and melamine resins, and thermoplastic resins such as polyethylene and polymethyl methacrylate.
[0030]
As the magnetic powder-dispersed core, those having an average particle diameter in the same range as the core material can be used, and the shape factor SF1 is preferably 125 or less. The true specific gravity is 3 to 5 g / cm.^ThreeThe saturation magnetization is preferably 40 emu / g or more.
[0031]
The shape factor SF1 is obtained by taking an optical microscope image of the magnetic material dispersed core dispersed on the surface of the slide glass into a Luzex image analyzer via a video camera, and obtaining a maximum length (ML) of 100 or more spherical cores. Measure the projected area (A), ML²It is obtained as an average value of / A.
[0032]
-Coating resin layer-
As the matrix resin of the coating resin layer in the present invention, for example, urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, phenol resin, epoxy resin, silicone resin, polyolefin resin such as polyethylene or polypropylene, Polyvinylidene resin, polystyrene, acrylic resin, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, Polyacrylonitrile, polyvinylcarbazole, polyurethane, amino resin, polymethyl methacrylate, fluororesin, styrene rubber, butyl rubber, butadiene rubber , Nitrile rubbers, ethylene - propylene rubber, Hypalon, acrylic rubber, urethane rubber, silicone rubber, fluorine rubber, or mixtures thereof. Moreover, the resin mentioned as a fluorine atom containing resin mentioned later can also be used.
[0033]
Among the above, it is preferable to use a nitrogen atom-containing resin, which is a highly charge-providing resin, as a binder, and this makes it possible to impart a high charge. The nitrogen atom-containing resin may be a thermoplastic resin or a thermosetting resin, but a thermosetting resin is preferred in terms of relatively high hardness.
[0034]
Examples of the nitrogen atom-containing resin include polyacrylonitrile, polyvinyl carbazole, polyurethane, amino resin, urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, styrene-dimethylaminoacrylate copolymer (hereinafter referred to as “St”). / DMAA ”may be abbreviated). Among these, melamine resin, styrene-dimethylaminoacrylate copolymer, benzoguanamine resin, urea resin, and polyurethane are preferably used, and melamine resin and benzoguanamine resin are particularly preferably used in terms of wear resistance.
[0035]
The resin contains a conductive component or additive. Examples of the conductive component include metals such as gold, silver and copper, carbon black, semiconductive oxides such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate, aluminum borate, and potassium titanate powder. There are tin oxide, carbon black, and metal covered on the surface. Among these, carbon black is preferable from the viewpoint of production stability, cost, and conductivity.
[0036]
The type of carbon black is not particularly limited, and known ones can be used, and carbon black having a DBP oil absorption in the range of 50 to 250 ml / g with particularly good production stability is preferred. Specifically, for example, Vulcan XC-72 (manufactured by Cabot), KETJEN black EC (manufactured by LIONNAKUZO), TOKABLACK 5500, 4500 (manufactured by Tokai Carbon Co., Ltd.), CONDUCTEX 975 (manufactured by COLUMBIAN CARBON), Print Conductive carbon black such as L (manufactured by Degussa); conductive graphite such as EPT-1 Powder (manufactured by Ogasawara Industrial Co., Ltd.); and other powders such as conductive zinc oxide T-1 (manufactured by Mitsubishi Materials) Examples thereof include tin oxide surface-treated with antimony and the like, and iron trioxide powder such as SE-0326 (manufactured by BASF).
In addition, it is preferable that the volume average particle diameter of these electroconductive materials is the range of 0.01-5 micrometers.
[0037]
The solvent used in the coating resin layer forming solution is not particularly limited as long as it dissolves the matrix resin. For example, aromatic hydrocarbons such as xylene and toluene; ketones such as acetone and methyl ethyl ketone Ethers such as tetrahydrofuran and dioxane; halides such as chloroform and carbon tetrachloride; and the like can be used.
[0038]
As a typical method of forming the coating resin on the surface of the core material of the carrier, a raw material solution for forming the coating resin layer (a matrix resin, resin fine particles, conductive fine powder, etc. are appropriately contained in a solvent) is used. Immersion method in which the powder of the material is immersed in the coating resin layer forming solution, spray method in which the coating resin layer forming solution is sprayed onto the surface of the core material, and for the coating resin layer formation in a state where the core material is suspended by flowing air Examples include a fluidized bed method in which a solution is sprayed, a kneader coater method in which a core material and a coating resin layer forming solution are mixed in a kneader coater, and then a solvent is removed, but the method is particularly limited to those using a solution. However, depending on the core material and the charge imparting member to be used, a powder coating method of heating and mixing together with the resin powder can be appropriately employed.
[0039]
The coating amount of the coating resin on the core material in the present invention is preferably in the range of 0.05 to 5.0% by mass with respect to the total mass of the carrier in order to balance image quality, secondary obstruction and chargeability. However, it is not necessarily limited to this range.
[0040]
<Resin carrier>
The resin carrier used in the present invention is obtained by dispersing magnetic fine particles in a binder resin.
-Magnetic particles-
Magnetic fine particles include usually used ferromagnetic materials, specifically, magnetic metals such as iron, cobalt and nickel; alloys thereof; Fe_ThreeO_Four , Γ-Fe₂O_ThreeFurther, metal oxides such as cobalt-added oxide and chromium oxide; powders such as Mn—Zn ferrite, Ni—Zn ferrite, magnetite, and hematite can be used. These magnetic fine particles preferably have a particle size in the range of 0.05 to 1.0 μm. The content of the magnetic fine particles is preferably in the range of usually 30 to 95% by mass with respect to the total weight of the resin carrier.
[0041]
-Binder resin-
As the binder resin for dispersing the magnetic fine particles, any plastic resin that is generally used can be used. As the binder resin used in the present invention, a resin obtained by homopolymerizing or copolymerizing the following monomers in addition to a polyolefin-based compound that is a polymer such as ethylene, propylene, butylene, and isobutylene can be used. That is, styrenes such as styrene, chlorostyrene, and vinyl styrene; monoolefins such as ethylene, propylene, acetylene, butylene, and isobutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; acrylic acid Α-methylene aliphatic monocarboxylic acid esters such as methyl, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; Homopolymers such as vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone: It can be exemplified coalescence.
[0042]
Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include a polymer, polyethylene, and polypropylene. Furthermore, polyesters, polyurethanes, epoxy resins, silicone resins, polyamides, modified rosins, paraffins, and waxes can be mentioned, but are not limited thereto.
[0043]
Moreover, resin, a charge control agent, a coupling agent, a filler, and other fine powders can be added to the resin carrier for chargeability control, dispersibility improvement, strength reinforcement, fluidity improvement, and other purposes.
[0044]
The resin carrier can be obtained by kneading, pulverizing, and classifying the binder resin, magnetic fine particles, and other components, and the components are liquefied by a solvent or heating, and a spray drying method or the like is performed. It can also be manufactured. As an apparatus for melting and mixing the magnetic fine particles and the binder resin, an attritor, a pressure kneader, a Banbury, a roll mill, a sand mill, a Henschel mixer, or the like can be used.
[0045]
Further, for the pulverization of the kneaded material, a collision plate type, a jet type or the like can be used. For example, in the case of a plate type, a microanalyzer, ulmax, jet-0-mizer, or a jet type has a KTM ( Krypton), turbo mill, etc. are used. Moreover, an I type jet mill etc. can be used as what has both these characteristics. The volume average particle diameter is preferably in the range of 10 to 400 μm, and more preferably in the range of 30 to 200 μm.
[0046]
<Dispersion of fluorine atom-containing resin on surface resin>
  In the present invention, the fluorine atom-containing resin is dispersed in the resin on the surface of the carrier by the following method.
  First, a core material in which a coating resin layer is formed or a magnetic resin dispersed in a binder resin is used as a fluorine atom-containing resin andLiquidBy contacting with a medium containing a dispersion medium, the surface resin (in the case of a resin-coated carrier, the coated resin layer) swells, and the fluorine atom-containing resinLiquidThe dispersion medium enters the resin. Next, when the dispersion medium is removed, only the fluorine atom-containing resin remains in the resin on the surface.
[0047]
When the fluorine atom-containing resin is left in the resin on the surface by the above method, the fluorine atom-containing resin penetrates uniformly into the swollen network-like resin at the molecular level. The peeling based on can be prevented. Further, since the fluorine atom-containing resin is uniformly dispersed on the resin surface, the chargeability of the toner can be made uniform.
[0048]
The medium includes a fluorine atom-containing resin and a dispersion medium.
-Fluorine atom-containing resin-
The fluorine atom-containing resin preferably has a critical surface tension γc of 35 mN / m or less, and more preferably 30 mN / m or less. If the critical surface tension exceeds 35 mN / m, the contamination of the toner on the surface of the electrostatic latent image developing carrier cannot be suppressed, and the chargeability and the change with time may tend to increase. .
[0049]
Specifically, the critical surface tension can be determined as follows.
First, several types of n-alkane liquids with known surface tensions (with surface tensions in the range of 20 to 40 mN / m) were prepared, and these were used as droplets with a syringe under an environment of 20 ° C. It is dropped on the fluorine atom-containing resin surface, and the contact angle θ of each droplet with respect to the fluorine atom-containing resin surface is measured by a contact angle meter (for example, automatic contact angle meter CA-Z, manufactured by Kyowa Interface Science Co., Ltd.).
[0050]
Next, the cos θ value of the contact angle value θ is plotted against the surface tension of each liquid (Zisman plot), and the surface tension value at the point where the extrapolated line of the plot intersects the line of cos θ = 1.0. Is the critical surface tension.
[0051]
Examples of such fluorine atom-containing resins include polyvinyl fluoride (γc = 28 mN / m), polyvinylidene fluoride (γc = 25 mN / m), polytrifluoroethylene (γc = 22 mN / m), polytetrafluoroethylene. (Γc = 18 mN / m), polyhexafluoropropylene (γc = 16 mN / m), a copolymer of vinylidene fluoride and an acrylic monomer, a copolymer of vinylidene fluoride and vinyl fluoride, Fluoroterpolymers such as terpolymers of tetrafluoroethylene with vinylidene fluoride and non-fluorinated monomers, such as perfluoroacrylate-hydroxyethyl methacrylate (hereinafter sometimes abbreviated as “HEMA”) copolymers Perfluoroacrylate copolymer, perfluorosulfonylamide copolymer And the critical surface tension is 35 mN / m or less.
[0052]
Moreover, these may be used individually by 1 type, may use 2 or more types together, may synthesize | combine suitably, and may use a commercial item.
Among the above, it is particularly preferable to use a mixture of a homopolymer of tetrafluoroethylene or vinylidene fluoride and a copolymer thereof.
[0053]
-Dispersion medium-
  The dispersion medium is one that disperses the fluorine atom-containing resin in a certain shape. However, the dispersion medium in the present invention may be a dispersion medium in which the fluorine atom-containing resin is dispersed in the form of fine particles. A dispersion medium in which the resin is almost dissolved (dispersed at the molecular level) may be used. The dispersion medium is liquidThe
[0054]
The dispersion medium is not particularly limited as long as it is an organic solvent that can swell the surface resin of the carrier other than water. For example, toluene, xylene, and alcohol that are solvents used in the coating resin layer forming solution Etc. can be used.
[0055]
In order to achieve both the dispersibility (solubility) of the fluorine atom-containing resin and the property of swelling the resin on the carrier surface, it is preferable to use a mixture of water and an organic solvent in a certain ratio. In this case, the organic solvent used by mixing with water is particularly preferably a paraffinic organic solvent, and the mixing ratio (A) / (B) of water (A) to the organic solvent (B) is 5/1 to 3 / 1 is preferable.
[0056]
The fluorine atom-containing resin is preferably uniformly dispersed (dissolved) in the medium, and the affinity between the resin on the carrier surface and the fluorine atom-containing resin needs to be improved. From such a viewpoint, the following can be added to the medium in addition to the fluorine atom-containing resin and the dispersion medium.
[0057]
For example, when the medium is an aqueous dispersion, the aqueous dispersion may further contain a wax and / or a low surface energy material (such as silicone). Here, examples of the wax include paraffin wax, microcrystalline wax, and petrolatum, and examples of the silicone include silicone oil, silicone gloss, oil compound, and silicone varnish. In addition, aqueous dispersions of fluorine atom-containing resins include fluorosurfactants, other anionic, cationic, nonionic or amphoteric surfactants, pH regulators, polyhydric alcohols, viscosity modifiers, stabilizers, and gloss. An agent or the like may be contained. Even in the case of an aqueous dispersion, it is desirable to use an appropriate amount of an organic solvent in combination as described above. Thus, by setting the dispersion medium and the surfactant to an optimum one, uniform and stable dispersion of the fluorine atom-containing resin in the aqueous dispersion can be achieved.
[0058]
In the case of an aqueous dispersion, the solid content concentration is set in the range of about 0.2 to 70% by mass, and the concentration of the fluorine atom-containing resin in the aqueous dispersion is in the range of about 0.2 to 50% by mass. However, in the present invention, when other dispersion medium is used, it is not necessarily limited to this range.
[0059]
-Contact between carrier and medium-
When the core material in which the coating resin layer is formed or in which the magnetic fine particles are dispersed in the binder resin is brought into contact with the medium, it is preferable to uniformly contact the entire carrier. For example, it can be easily carried out by immersing the carrier in a liquid medium, and in particular under reduced pressure, for example 8.0 × 10^FourPa or less, more preferably 6.7 × 10^FourIt is desirable to carry out under the conditions of Pa or less.
[0060]
The contact is performed by spraying an aqueous dispersion of a fluorine atom-containing resin (spray method) or coating a core resin with a coating resin layer or a magnetic resin dispersed in a binder resin. (Coating method) can also be achieved.
[0061]
The speed at which the resin on the carrier surface swells and penetrates by the fluorine atom-containing resin can be controlled by the concentration of the fluorine atom-containing resin in the medium, the medium temperature at the time of swelling, and the like. The temperature of the medium when the carrier is in contact with the liquid medium is preferably in the range of 20 to 150 ° C., and the contact time is preferably 15 minutes or longer, preferably 30 minutes or longer, but is not limited thereto. Moreover, immersion (contact) can also be repeated several times.
[0062]
The fluorine atom-containing resin content in the resin on the surface is preferably in the range of 1 to 65% by mass, and more preferably in the range of 20 to 35% by mass. If the content is less than 1% by mass, the effect of lowering the surface energy of the resin surface may not be obtained. If the content exceeds 65% by mass, the fluorine atom-containing resin is detached from the surface resin. It may be easier.
[0063]
Moreover, it is preferable that the sea surface tension of the resin surface in which the fluorine atom-containing resin is dispersed is 35 mN / m or less.
[0064]
This method uses the swelling property of polymers, and in the case of crosslinks between molecules like a network polymer, it absorbs a certain amount of solvent to form a gel, and beyond that, it reaches equilibrium and changes. No longer. As the linear polymer swells, the individual molecules are merely agglomerated by van der Waals forces, so that they are gradually disentangled and finally completely dissolved. However, in the present invention, the linear polymer can be stopped in the swollen state by adjusting the ratio of water and organic solvent in the medium to an appropriate range as described above. Can be used.
[0065]
Through the above operation, the aqueous dispersion liquid in which the fluorine atom-containing resin has entered the surface resin after the coating resin layer is formed on the core material or the magnetic fine particles are dispersed in the binder resin and then adhered to the surface. It is more preferable to remove (medium) by washing or wiping. If the fluorine atom-containing resin remains on the surface of the carrier, the surface properties are deteriorated, and the uniform chargeability may be inferior. After the washing or wiping, it is necessary to remove the water (dispersion medium) by drying the carrier under heating or at room temperature. If water remains in the vicinity of the carrier surface, the charge imparting property and the environmental stability are inferior.
[0066]
<< Electrostatic latent image developer >>
The electrostatic latent image developer of the present invention contains a toner and a carrier, and the carrier is the electrostatic latent image developing carrier of the present invention.
[0067]
The toner is not particularly limited and can be suitably selected from commonly used known toners. Usually, the toner has a binder resin and a colorant, and other components (internal additives) as necessary. Agent).
[0068]
<Binder resin>
Examples of the binder resin used in the toner in the present invention include styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isoprene; vinyls such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate. Esters; (meth) acrylic acid, vinyl acetic acid, allyl acetic acid, unsaturated carboxylic acids such as 10-undecenoic acid; styrene derivatives having a carboxyl group such as carboxyl styrene; methyl acrylate, ethyl acrylate, butyl acrylate, Α-methylene aliphatic monocarboxylic acid esters such as dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl methyl ether, vinyl ethyl ether, Examples of vinyl ethers such as nylbutyl ether; homopolymers and copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, etc. In particular, as representative binder resins, List polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene, etc. Can do.
[0069]
Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like. Among these, the case where polyester is used as a binder resin is particularly effective. For example, a linear polyester resin made of a polycondensate containing bisphenol A and polyvalent aromatic carboxylic acid as main monomer components can be preferably used. Moreover, the softening point is 90 to 150 ° C., the glass transition point is 50 to 70 ° C., the number average molecular weight is 2000 to 6000, the weight average molecular weight is 8000 to 150,000, the acid value is 5 to 30, and the hydroxyl value is 5 to 40. A resin exhibiting can be particularly preferably used.
[0070]
In the present invention, a two-component developer composed of a toner and a carrier can be used. However, when the electrostatic latent image developing carrier of the present invention is used as a carrier, the toner binder resin contains a carboxyl group. It is preferable to contain a monomer. Thereby, the negative charging property on the toner side can be improved, the spent resistance of the carrier can be improved, and the charge imparting characteristics as a developer can be maintained.
[0071]
Examples of the carboxyl group-containing monomer include unsaturated carboxylic acids such as (meth) acrylic acid, vinyl acetic acid, allyl acetic acid, and 10-undecenoic acid, styrene derivatives having a carboxyl group such as carboxyl styrene, p- Examples thereof include those containing two or more carboxyl groups such as carboxyl styrene.
[0072]
<Colorant>
Examples of the colorant used in the toner of the present invention include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, and phthalocyanine blue. , Malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 173, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative one.
[0073]
<Other ingredients>
Examples of the other components include a charge control agent that can be added for the purpose of controlling the chargeability of the toner, and a release agent such as wax that can be added for the purpose of preventing hot offset in the toner fixing step.
[0074]
Typical examples of the release agent include low molecular polyethylene, low molecular polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.
[0075]
Further, as described above, the toner in the present invention may contain an additive such as a charge control agent as necessary. Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. It is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination.
[0076]
<Production of toner>
The toner is not particularly limited, but can be prepared as follows.
For example, the above-described components (binder resin, colorant, and other components) are mixed, melt-kneaded, and then pulverized to produce a toner having a volume average particle size of 3 to 20 μm. The melt kneading is not particularly limited, but a Banbury mixer, a kneader, an extruder, etc. are preferably used. Although there is no restriction | limiting in particular in the said grinding | pulverization, A jet mill etc. are used suitably.
[0077]
The toner particles of the present invention suitably have a shape factor SF1 in the range of 100 to 135, and it is preferable to use a wet method for producing such toner. In the wet method, 1) a resin fine particle dispersion obtained by emulsion polymerization of a polymerizable monomer of a binder resin, a colorant dispersion, a release agent dispersion, and a dispersion such as a charge control agent as required An emulsion polymerization aggregation method in which toner particles are obtained by mixing, forming aggregated particles, and fusing and coalescing, b) a polymerizable monomer and a colorant, a release agent, and a binder resin, if necessary Suspension polymerization method in which a solution such as a charge control agent is suspended in an aqueous solvent and polymerized to obtain toner particles, c) a binder resin and a colorant, a release agent, and a solution such as a charge control agent as required. There is a dissolution suspension method in which the mixture is suspended in an aqueous solvent and granulated. Among these, the emulsion polymerization aggregation method is most suitable. By using the spherical toner, the contact area with the carrier is reduced, so that the spent resistance can be further improved.
[0078]
The toner in the present invention may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material. These toner particles include known charge control agents, fluidity improvers, and fixing aids. In addition to such additives, magnetic powder may be included as necessary. The particle diameter of the toner tends to become smaller as the image quality becomes higher, and the volume average particle diameter is desirably 2 to 12 μm, preferably 5 to 10 μm.
[0079]
If necessary, other components (external additives) are attached to the surface of the obtained toner to obtain a toner.
Examples of such other components (external additives) include inorganic fine particles such as silicon oxide, titanium oxide, and aluminum oxide that have been subjected to surface hydrophobization treatment with a volume average particle diameter of 5 to 200 nm, and organic materials such as polymethyl methacrylate fine particles. Examples thereof include fine particles.
[0080]
The electrostatic latent image developer of the present invention is produced by mixing the above-described toner and carrier. The mixing ratio (mass ratio) of the toner and the carrier in the developer is preferably in the range of toner: carrier = 1: 100 to 20: 100, preferably in the range of 3: 100 to 12: 100. It is more preferable.
[0081]
<< Image Forming Method >>
The image forming method of the present invention includes a step of forming an electrostatic latent image on the surface of the electrostatic latent image load bearing member, and a step of developing the electrostatic latent image with a developer on the surface of the developer bearing member to form a toner image. An image forming method comprising: a transfer step of transferring the toner image to a surface of a recording medium to form a transfer image; and a fixing step of fixing the transfer image transferred to the surface of the recording medium. The electrostatic latent image developer of the present invention.
[0082]
The step of forming the electrostatic latent image means that the surface of the electrostatic latent image carrier is uniformly charged by a charging means, and then exposed to the electrostatic latent image carrier with a laser optical system or an LED array, This is a step of forming an electrostatic latent image. As the charging means, the surface of the electrostatic latent image carrier is applied by applying a voltage to a non-contact charger such as corotron or scorotron, and a conductive member brought into contact with the surface of the electrostatic latent image carrier. Examples of the charging device include a contact type charging device, and any type of charging device may be used. However, a contact charging type charger is preferable from the viewpoint that the amount of ozone generated is small, environmentally friendly, and excellent printing durability. In the contact charging type charger, the shape of the conductive member may be any of a brush shape, a blade shape, a pin electrode shape, a roller shape, and the like, but a roller-like member is preferable.
The image forming method of the present invention is not subject to any particular limitation in the electrostatic latent image forming process.
[0083]
The step of forming the toner image includes bringing a developer carrier having a developer layer containing at least toner on the surface thereof into contact with or approaching the surface of the electrostatic latent image carrier. In this step, toner particles are attached to the electrostatic latent image on the surface to form a toner image on the surface of the electrostatic latent image carrier. The development method can be performed using a known method, and examples of the development method using the two-component developer used in the present invention include a cascade method and a magnetic brush method. The image forming method of the present invention is not particularly limited with respect to the developing method.
[0084]
The transfer step is a step of transferring a toner image formed on the surface of the electrostatic latent image carrier to a recording medium to form a transfer image. In the case of color image formation, it is preferable that each color toner is primarily transferred to an intermediate transfer drum or belt and then secondarily transferred to a recording medium such as paper.
[0085]
A corotron can be used as a transfer device for transferring a toner image from the photosensitive member to paper or an intermediate transfer member. The corotron is effective as a means for uniformly charging the paper, but a high voltage of several kV must be applied and a high voltage power source is required in order to give a predetermined charge to the paper as a recording medium. In addition, ozone is generated by corona discharge, which causes deterioration of rubber parts and photoreceptors. Contact transfer system that transfers a toner image onto paper by pressing a conductive transfer roll made of an elastic material against the image carrier. Is preferred.
In the image forming method of the present invention, the transfer device is not particularly limited.
[0086]
The fixing step is a step of fixing the toner image transferred to the surface of the recording medium with a fixing device. As the fixing device, a heat fixing device using a heat roll is preferably used. The heat fixing device includes a fixing roller having a heater lamp for heating inside a cylindrical metal core, a so-called release layer formed on the outer peripheral surface by a heat resistant resin film layer or a heat resistant rubber film layer, and the fixing roller. The pressure roller or pressure belt is disposed in pressure contact with the roller and has a heat-resistant elastic body layer formed on the outer peripheral surface of the cylindrical metal core or the surface of the belt-like base material. The fixing process of the unfixed toner image is performed by inserting a recording material on which an unfixed toner image is formed between a fixing roller and a pressure roller or a pressure belt, and using a binder resin, an additive, and the like in the toner. Fix by heat melting.
In the image forming method of the present invention, the fixing method is not particularly limited.
[0087]
Examples of the recording material to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines and printers. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer object is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.
[0088]
In the image forming method as described above, by using the developer containing the electrostatic latent image developing carrier of the present invention as described above, it is possible to suppress the environmental dependency and form a good image.
[0089]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited by these.
(Preparation of carriers A and D)
Ferrite particles (Mn—Mg ferrite, volume average particle size: 40 μm): 100 parts by mass
・ Polymethyl methacrylate: 1.2 parts by mass
・ Toluene: 14 parts by mass
[0090]
Prepare the coating resin layer forming solution by dissolving the above polymethyl methacrylate in toluene, put it in a vacuum degassing type kneader with ferrite particles, keep the temperature at 60 ° C and stir for 10 minutes, then depressurize and distill off the toluene Then, a coating resin layer was formed on the surface of the ferrite particles, and sieved with a mesh having a mesh opening of 75 μm to obtain a carrier D.
[0091]
50 parts by mass of carrier D was dispersed in an aqueous fluororesin dispersion (composition: water 80% by mass, fluorosurfactant 7% by mass, polytetrafluoroethylene 3% by mass (γc: 28 mN / m), paraffin wax 1% by mass, paraffin After putting in a vacuum degassing type kneader together with 50 parts by mass of a medium-boiling solvent (6% by mass, ethylene glycol 3% by mass) and sufficiently contacting the mixture, stirring at 60 ° C. for 60 minutes, reducing the pressure to −100 kPa and toluene. Water was removed, a resin layer in which the fluorine atom-containing resin was dispersed was formed, and sieved with a mesh having an opening of 75 μm to obtain carrier A.
[0092]
(Preparation of carrier F)
Ferrite particles (Mn—Mg ferrite, volume average particle size: 40 μm): 100 parts by mass
Perfluoroacrylate copolymer (γc: 28 mN / m, perfluorooctylethyl acrylate / methyl methacrylate copolymer, copolymerization ratio 60:40, mass average molecular weight Mw: 70000): 1.2 parts by mass
Cross-linked melamine resin particles (average particle size: 0.3 μm): 0.25 parts by mass
Carbon black (VXC72: manufactured by Cabot): 0.12 parts by mass
・ Toluene: 14 parts by mass
[0093]
The above components except for the ferrite particles as a core material are dissolved and dispersed with a stirrer for 10 minutes to prepare a coating resin layer forming solution, and placed in a vacuum degassing type kneader together with the ferrite particles to maintain the temperature at 60 ° C. 10 After stirring for a minute, toluene was distilled off under reduced pressure to form a coating resin layer on the surface of the ferrite particles, and sieved with a mesh having an opening of 75 μm to obtain Carrier F.
[0094]
(Preparation of carriers B and H)
-Magnetic fine particle dispersed carrier core (manufactured by Toda Kogyo Co., Ltd., matrix resin: phenol resin, true specific gravity 3.7 g / cm^Three , Volume average particle size 40 μm, saturation magnetization 60 emu / g, shape factor SF1: 105): 100 parts by mass
・ Polyisobutyl methacrylate: 0.7 parts by mass
・ Toluene: 14 parts by mass
[0095]
The polyisobutyl methacrylate is dissolved in toluene to prepare a solution for forming a coating resin layer. The solution is placed in a vacuum degassing kneader with the magnetic fine particle dispersed carrier core and stirred at a temperature of 60 ° C. for 10 minutes. Then, toluene was distilled off to form a coating resin layer on the surface of the above-mentioned magnetic fine particle-dispersed carrier core, and sieved with a mesh having an opening of 75 μm to obtain carrier H.
[0096]
50 parts by mass of carrier H is placed in a vacuum degassing type kneader together with 40 parts by mass of a fluororesin aqueous dispersion (Z-100, manufactured by Eco Oil Co.), kept at a temperature of 75 ° C. and stirred for 60 minutes, and then reduced in pressure to toluene. And water were removed, a resin layer in which the fluorine atom-containing resin was dispersed was formed, and sieved with a mesh having an opening of 75 μm to obtain carrier B.
[0097]
(Preparation of carrier E)
Ferrite particles (Mn—Mg ferrite, volume average particle size: 40 μm): 100 parts by mass
-Perfluorooctyl ethyl acrylate polymer (γc: 25 mN / m): 1.7 parts by mass
・ Toluene: 14 parts by mass
[0098]
A perfluorooctylethyl acrylate polymer is dissolved in toluene to prepare a coating resin layer forming solution. The solution is placed in a vacuum degassing type kneader together with ferrite particles and stirred at a temperature of 60 ° C. for 10 minutes. The carrier resin E was obtained by forming a coating resin layer on the surface of the ferrite particles and sieving with a mesh having an opening of 75 μm.
[0099]
(Preparation of carriers C and G)
Magnetic core dispersed carrier core (manufactured by Toda Kogyo Co., Ltd., matrix resin: phenol resin, true specific gravity: 3.7 g / cm^Three , Volume average particle size: 40 μm, saturation magnetization: 60 emu / g, shape factor SF1: 105): 100 parts by mass
Perfluoroacrylate copolymer (γc: 28 mN / m, perfluorooctylethyl acrylate / methyl methacrylate copolymer, copolymerization ratio 60:40, weight average molecular weight Mw: 70000): 1.2 parts by mass
Crosslinked melamine resin particles (average particle size: 0.3 μm): 0.3 parts by mass
Carbon black (VXC72: manufactured by Cabot): 0.15 parts by mass
・ Toluene: 14 parts by mass
[0100]
Except for the magnetic fine particle-dispersed carrier core as a core material, the above components are dissolved and dispersed with a stirrer for 10 minutes to prepare a coating resin layer forming liquid, and put into a vacuum degassing kneader together with the magnetic fine particle-dispersed carrier core. After maintaining the temperature at 60 ° C. and stirring for 10 minutes, the pressure is reduced and toluene is distilled off to form a coating resin layer on the surface of the magnetic fine particle-dispersed carrier core. Obtained.
[0101]
50 parts by mass of carrier G was mixed with an aqueous fluororesin dispersion (composition: 11% by mass perfluoroacrylate polymer (γc: 28 mN / m), 20% by mass paraffinic medium boiling point solvent, surfactant, viscosity modifier and stabilizer 10 (Mass%, water 59 mass%) A resin in which 30 parts by mass is placed in a vacuum degassing kneader and the temperature is kept at 75 ° C. and stirred for 60 minutes, then the pressure is reduced to remove toluene and water, and a fluorine atom-containing resin is dispersed. A layer was formed and sieved with a mesh having an opening of 75 μm to obtain Carrier C.
[0102]
(Preparation of toner a)
-Preparation of resin fine particle dispersion (1)-
・ Styrene: 370 parts by mass
-N-butyl acrylate: 30 parts by mass
-Acrylic acid: 8 parts by mass
・ Dodecanethiol: 24 parts by mass
・ Carbon tetrabromide: 4 parts by mass
[0103]
The above components are mixed and dissolved to prepare a raw material solution, and 6 parts by weight of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd.) : Neogen SC) To 10 parts by mass dissolved in 550 parts by mass of ion-exchanged water, the above raw material solution was added, dispersed and emulsified in a flask, mixed slowly for 10 minutes, and 4 parts by mass of ammonium persulfate. After adding 50 parts by mass of ion-exchanged water dissolved in nitrogen, and performing nitrogen substitution, the contents in the flask were heated with an oil bath until the contents reached 70 ° C. while stirring, and the emulsion polymerization was carried out at 70 ° C. for 5 hours. Continuously, a resin fine particle dispersion (1) was obtained. The resin fine particles had a volume average particle size of 155 nm, a Tg of 59 ° C., and a weight average molecular weight Mw of 12,000.
[0104]
-Preparation of resin fine particle dispersion (2)-
・ Styrene: 280 parts by mass
N-butyl acrylate: 120 parts by mass
-Acrylic acid: 8 parts by mass
[0105]
The above components are mixed and dissolved to prepare a raw material solution, and 6 parts by weight of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd.) : Neogen SC) 12 parts by mass dissolved in 550 parts by mass of ion-exchanged water, the above raw material solution was added, dispersed and emulsified in a flask, mixed slowly for 10 minutes, and 3 parts by mass of ammonium persulfate. After adding 50 parts by mass of ion-exchanged water dissolved in nitrogen, and performing nitrogen substitution, the contents in the flask were heated with an oil bath until the contents reached 70 ° C. while stirring, and the emulsion polymerization was carried out at 70 ° C. for 5 hours. Continuously, a resin fine particle dispersion (2) was obtained. The resin fine particles had a volume average particle size of 105 nm, a Tg of 53 ° C., and a mass average molecular weight Mw of 550,000.
[0106]
-Preparation of colorant dispersion (1)-
Carbon black (Cabot Corporation: Mogal L): 50 parts by mass
Nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd .: Nonipol 400): 5 parts by mass
・ Ion exchange water: 200 parts by mass
[0107]
A colorant dispersion obtained by mixing and dissolving the above components, dispersing for 10 minutes using a homogenizer (manufactured by IKA: Ultra Turrax T50), and dispersing a colorant (carbon black) having a volume average particle size of 250 nm. (1) was obtained.
[0108]
-Preparation of release agent dispersion (1)-
Paraffin wax (Nippon Seiwa Co., Ltd .: HNP0190, melting point 85 ° C.): 50 parts by mass
Cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 5 parts by mass
・ Ion exchange water: 200 parts by mass
[0109]
The above components are heated to 95 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a pressure discharge homogenizer to disperse a release agent having a volume average particle size of 550 nm. A release agent dispersion (1) was obtained.
[0110]
-Preparation of aggregated particle dispersion-
・ Resin fine particle dispersion (1): 120 parts by mass
・ Resin fine particle dispersion (2): 80 parts by mass
Colorant dispersion (1): 30 parts by mass
-Release agent dispersion (1): 40 parts by mass
Cationic surfactant (manufactured by Kao Corporation: Sanizol B50): 1.5 parts by mass
[0111]
The above components were mixed and dispersed in a round stainless steel flask using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then heated to 50 ° C. while stirring the inside of the flask in an oil bath for heating. Thereafter, the mixture was cooled to 45 ° C. and held for 25 minutes to obtain an aggregated particle dispersion. When the obtained aggregated particles were observed with an optical microscope, the average particle size was about 5.0 μm.
[0112]
-Preparation of adhered particle dispersion-
To the above aggregated particle dispersion, 60 parts by mass of the resin fine particle dispersion (1) was gently added. And the temperature of the oil bath for heating was raised to 50 degreeC, and it hold | maintained for 40 minutes, and obtained the adhesion particle dispersion liquid. When the obtained adhered particles were observed with an optical microscope, the average particle size was about 5.8 μm.
[0113]
-Manufacture of toner particles-
3 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) is added to the above adhering particle dispersion, the stainless steel flask is sealed, and stirring is continued using a magnetic seal. However, it heated to 105 degreeC and hold | maintained for 4 hours. Thereafter, the mixture was cooled, the reaction product was filtered, thoroughly washed with ion exchange water, and dried to obtain a toner. The obtained toner had a volume average particle diameter D50 of 6.0 μm and a shape factor SF1 of 106.
[0114]
(Preparation of toner b (melt kneaded toner))
Styrene / n-butyl methacrylate resin (copolymerization ratio 70:30, weight average molecular weight Mw: 200000, manufactured by Sanyo Chemical Industries): 89 parts by mass
Carbon black (Mogal L, manufactured by Cabot): 6 parts by mass
Polypropylene wax (660P, manufactured by Sanyo Chemical Co., Ltd.): 5 parts by mass
A toner b having a volume average particle diameter D50 of 6 μm was obtained by a melt-kneading pulverization method using the above components.
[0115]
-External additive (1)-
Needle-shaped rutile-type titanium oxide decylsilane-treated compound (volume average particle diameter: 15 nm, powder resistance: 10¹⁵Ω · cm)
[0116]
-External additive (2)-
Spherical monodispersed silica obtained by subjecting silica sol obtained by the sol-gel method to HMDS treatment, drying and pulverization (shape factor SF1: 105, volume average particle size: 135 nm, powder resistance: 10¹⁵Ω · cm)
[0117]
(Preparation of electrostatic latent image developers 1 to 9)
After adding 1 part by mass of external additive (1) and 1 part by mass of external additive (2) to 100 parts by mass of each of the toners described above, blending for 10 minutes at 30 m / sec using a Henschel mixer, then 45 μm Coarse particles were removed using a mesh sieve to prepare externally added toners a and b.
[0118]
In the combinations shown in Table 1, 7 parts by mass of the externally added toner a or b and 100 parts by mass of each of the carriers (A) to (G) were stirred for 20 minutes at 40 rpm using a V blender, and a 125 μm mesh was obtained. Sieving was performed using a sieve to obtain developers 1 to 9.
[0119]
[Table 1]

[0120]
(Examples 1-3, Comparative Examples 1-6)
Developers 1 to 9 using the externally added toner a or b as toner are left in a high temperature and high humidity environment (28 ° C., 80 RH%) and a low temperature and low humidity environment (10 ° C., 15 RH%) respectively for a day and night. Applicable to Xerox A-color 936 developer, 50,000 images were printed in each environment. Image quality evaluation and chargeability evaluation of initial (first image) and 50,000th image samples And went.
[0121]
The chargeability evaluation was performed by measuring the toner charge amount by the blow-off method, and the image quality evaluation was performed mainly by visual evaluation of fog. The evaluation criteria are as follows.
[0122]
-Image quality evaluation criteria-
A: There is no fog and it is very good.
○: There is some fog, but there is no practical problem.
Δ: Slightly more fog and practical problems.
X: fog is conspicuous.
The results are shown in Table 2. In Table 2, film peeling was confirmed by observing the carrier surface using a scanning electron microscope.
[0123]
[Table 2]

[0124]
As is clear from the results in Table 2, in the developers using the electrostatic latent image developing carriers of Examples 1 to 3 of the present invention, the initial toner chargeability and image quality in the high temperature and high humidity environment and the low temperature and low humidity environment are as follows. Both were very good, and the toner chargeability and image quality at the 50,000th sheet were also good.
[0125]
On the other hand, the developer of Comparative Example 1 had good initial toner chargeability and image quality in a high temperature and high humidity environment and a low temperature and low humidity environment, but the toner charge amount at the 50,000th sheet in a high temperature and high humidity environment. The toner surface was contaminated with toner, and the image was fogged. The developer of Comparative Example 2 had good initial toner chargeability and image quality in a low-temperature and low-humidity environment, but the initial toner charge amount in a high-temperature and high-humidity environment was low, and the image quality was somewhat poor. At the 50,000th sheet, the coating resin of the carrier was peeled off and carrier scattering was observed.
[0126]
The developer of Comparative Example 3 was not bad in initial toner chargeability and image quality at the 50,000th sheet, but although the generation time was later than that of Comparative Example 1, toner scattering occurred. Some practical problems occurred in the toner charge amount and image quality at the 50,000th sheet in the high temperature and high humidity environment and the low temperature and low humidity environment. The developer of Comparative Example 4 showed toner chargeability and image quality higher than those of Comparative Example 3, but there were practical problems in the toner charge amount and image quality at the 50,000th sheet in a high temperature and high humidity environment.
[0127]
The developer of Comparative Example 5 was not bad in initial toner chargeability image quality, but the toner chargeability and image quality at the time of the 50,000th sheet in a high temperature and high humidity environment were lowered, and there were practical problems even in a low temperature and low humidity environment. .
[0128]
【The invention's effect】
According to the present invention, it is possible to provide an electrostatic latent image developing carrier excellent in chargeability, charge imparting maintenance property, environmental stability, durability, and stain resistance, and a developer using the carrier. It is also possible to provide an image forming method capable of forming the above image.

Claims (3)

A carrier for developing an electrostatic latent image having a resin on the surface, wherein the resin is swollen by contacting with a medium containing a fluorine atom-containing resin and a liquid dispersion medium, and the fluorine atom-containing resin enters the resin. Thereafter, the carrier for developing an electrostatic latent image is characterized in that a fluorine atom-containing resin is dispersed in the resin by removing the dispersion medium.   An electrostatic latent image developer comprising a toner and a carrier, wherein the carrier is the electrostatic latent image developing carrier according to claim 1. A step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer on the surface of the developer carrier, and forming a toner image; An image forming method comprising a transfer step of transferring to a surface to form a transferred image, and a fixing step of fixing the transferred image transferred to the surface of the recording medium,
The image forming method according to claim 2, wherein the developer is the electrostatic latent image developer according to claim 2.