JP2004177621A - Magnetic toner for electrostatic image development and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic toner for electrostatic image development for suppressing contamination on the surface of a heat roller and for obtaining stable fixing property and image quality with almost no environmental dependence, and to provide an image forming method. <P>SOLUTION: The magnetic toner for electrostatic image development is produced by a wet manufacturing method and comprises magnetic powder and a binder resin containing a condensation polymerization compound of a polymerizable monomer having ≤8C organic oxy acid. The image forming method includes processes of: forming an electrostatic latent image on an electrostatic latent image carrying body; forming a toner image 11 by developing the electrostatic latent image with a developer layer on a developer carrying body; transferring the toner image 11 onto a transfer material 10; and fixing the toner image 11 on the surface of the fixing base material. The toner for forming the toner image 11 in the method is the above magnetic toner for electrostatic image development. <P>COPYRIGHT: (C)2004,JPO

Description

上記材料をヘンシェルミキサーにより粉体混合し、これを設定温度１４０℃のエクストルーダー（混練時の材料の溶融粘度：ＭＩ １６．５ｇ／１０ｍｉｎ）により混練した。冷却後、粗粉砕、微粉砕し５０％体積径Ｄ５０が６．９μｍの粉砕品を得た。さらにこの粉砕品を分級して得られたトナーの重量平均粒径は６．５μｍであった。得られたトナー粒子１００部に対して、コロイダルシリカ（日本アエロジル社製、Ｒ９７２）１．５部を外添し、ヘンシェルミキサーを用いて混合することにより、静電荷像現像磁性用トナー（４）を得た。
【０１３６】
このトナーの個数粒度はｄ５０が４．５６μｍで粒度分布は１．３１であった。
この得られた磁性トナーを遠心分離にかけ、遊離磁性粉量を測定した所０．０６ｖｏｌ％であった。
【０１３７】
径３５ｍｍのヒートロール表面にフッ素樹脂層を設け、ＳｉＣ粒子径２．４μｍを４．２％添加した実施例１同様、富士ゼロックス社製「Ｌａｓｅｒ Ｐｒｅｓｓ ４１６１ＩＩ」（登録商標）の改造機を使用して、定着のプロセススピードが２２０ｍｍ／ｓとなるように、実施例１と同様にランニングテストと画質評価を行なった。
【０１３８】
【表１】

【０１３９】
（評価基準）
１８０℃定着でオフセット発生の有無を確認し、オフセットがない場合を「○」、オフセット発生の場合「×」とした。また、ヒートロール汚れは、２０万枚プリント後ヒートロール表面を目視で、汚れの有無を確認し、目視で汚れを発見できなかった場合は「○」、一方目視で汚れを発見した場合には「×」とした。
【０１４０】
上記結果から以下のことが明らかなように、実施例１〜３で作成された現像剤の帯電性は、比較例１〜２で作成された現像剤の帯電性に比較して、夏環境、冬環境での帯電量の環境差が少なく、２０万枚連続操作の後も遊離した磁性粉が起因となるような定着ヒートロール汚れを防ぎ、長期にわたり定着装置に対する悪影響がでない静電荷像現像用トナーおよび静電荷像現像剤を得ることができた。
【図面の簡単な説明】
【図１】本発明の画像形成方法の定着工程に用いられる定着装置の一例を示す概略図である。
【符号の説明】
１ ヒートローラ、２ 加熱部材、３ 温度センサ、４ プレッシャーローラ、５ 離型樹脂層、６ 示温部材、１０ 転写材、１１ トナー像。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic toner for developing electrostatic images and an image forming method which are excellent in the reliability of high-quality images and the transparency of images, and are preferably used when forming images by electrophotography or the like.
[0002]
[Prior art]
Dry development methods in various electrostatic copying systems currently in practical use include a two-component development method using a toner and a carrier such as iron powder, and a toner containing a magnetic substance inside the toner without using a carrier. The magnetic one-component developing system used is known. In the magnetic one-component developing method using only magnetic toner, there is no need to use an automatic density controller required for a two-component developing method, so the developing machine is compact, and there is no carrier contamination, so the carrier is replaced. Such maintenance is not required.
[0003]
For this reason, in recent years, copiers, printers and multifunction devices using the magnetic one-component developing method have begun to be used in the field of personal copying for small offices and individuals such as SOHO, and the size of the apparatus has been reduced even though the speed of the apparatus has increased. Lightening is required.
[0004]
In addition, devices such as copying machines and printers are required to be reduced in size and weight, while energy saving, high durability and high reliability are increasingly required in recent years.
[0005]
In order to save energy, a heating member such as a lamp heater for heating the heat roller of the fixing device is set at a lower temperature in a normal standby state than in operation.
[0006]
On the other hand, since fixing is performed by heating with a heating member such as a lamp heater at the time of operation, there is a strong demand from the market to reduce the waiting time for printing the first sheet. On the other hand, the heat roll is made thinner or a material having a high thermal conductivity is selected as a material for the heat roller, so that the heat roll reaches the fixing temperature in a short time.
[0007]
On the other hand, the heat roller tends to be easily affected by the temperature fluctuation of the heating member such as the lamp heater.
[0008]
Further, foreign matters such as small-diameter developer and paper powder may enter into the concaves and convexes on the surface of the heat roll, and in such a case, the releasability of the roll surface is reduced. Usually, in the case of a plurality of prints, since foreign matter that has entered the depressions on the surface of the heat roller adheres to the second and subsequent sheets, the foreign matter on the surface of the heat roller is removed, and there is almost no problem. Since the small-diameter developer and the developer attached to the foreign matter enter into the concaves and convexes on the surface of the heat roll and cannot be removed, the printer returns from the standby state of the heating member in a personal printer or a facsimile that frequently prints a single sheet. Due to the heat of the overshoot, the developer that has entered the depression on the surface of the heat roller is deformed, and the volatile components in the developer evaporate and are fixed in the depressions on the surface of the heat roll. Although it did not come out, there was a possibility that a non-visual offset (hereinafter referred to as “NVO”) causing hot offset on the heat roll surface was generated.
[0009]
In the above case, there is a problem in that the surface of the heat roll is contaminated with the developer, and as the number of fixed images further advances, the contamination progresses, and the ability of the heat roll to separate from the developer decreases, resulting in hot offset.
[0010]
In order to solve such a problem, Patent Document 1 proposes that the diameter of the depressions of the irregularities on the surface of the heat roll is made smaller than the particle diameter of the developer in order to prevent the developer from being contaminated on the surface of the heat roll. Although this method is effective in the initial state, it is effective when the free magnetic powder is buried in the cavities and the surface releasability is reduced, especially when the process speed is fast with a small-diameter heat roll. Since the surface is damaged, good releasability cannot be maintained, and as a result, generation of NVO cannot be prevented. Therefore, the above-mentioned ones cannot be said to be effective means for demanding high durability and high reliability.
[0011]
In addition, even when inorganic particles such as SiC are added to the surface of the heat roll to prevent abrasion of the surface of the heat roller, the free magnetic powder wears around the inorganic particles on the surface of the heat roller. The particles are detached, and a pit is formed on the surface of the heat roller. In such a case, it is difficult to prevent the surface of the heat roll from being contaminated by the developer and the generation of NVO due to the progress of the contamination, as in the case of the above-described heat roller scratches.
[0012]
Further, in order to suppress the generation of the NVO and enhance the protection of the global environment, some toners using a biodegradable polymer or a polylactic acid resin as a binder resin have been proposed (for example, Patent Documents). 2 to Patent Document 6).
[0013]
However, since all toners use the kneading and pulverizing method, when producing a magnetic toner, the interface between the binder resin and the magnetic powder is broken at the time of pulverization, and the magnetic powder is exposed or detached on the toner surface. As a result, the chargeability of the toner becomes unstable, and the magnetic powder detached from the toner surface damages the heat roller surface. Then, NVO may still occur.
[0014]
[Patent Document 1]
JP-A-56-69674
[Patent Document 2]
JP-A-04-179967
[Patent Document 3]
JP-A-04-218063
[Patent Document 4]
JP 09-281746 A
[Patent Document 5]
JP 2001-022123 A
[Patent Document 6]
Japanese Patent Application Laid-Open No. 2001-166637
[0015]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and aims to solve the problems of the conventional technology.
[0016]
That is, the object of the present invention is to prevent the generation of NVO without contaminating the surface of the heat roll for a long time even at a high process speed using a small-diameter heat roll, to form a good image without hot offset, An object of the present invention is to provide a high-speed and highly reliable magnetic toner for electrostatic image development and an image forming method.
[0017]
[Means for Solving the Problems]
The means for solving the above problems are as follows. That is,
(1) In a toner produced by a wet process, the toner comprises a binder resin containing a polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms, and a magnetic powder for electrostatic image development. Magnetic toner.
[0018]
(2) The magnetic toner according to (1), wherein the organic oxyacid is lactic acid.
[0019]
(3) The toner particles of the magnetic toner for electrostatic image development have a volume average particle diameter of 3 to 10 μm, and a particle size distribution calculated from the number average particle diameter of the toner particles is 1.13 or more and 1.30 or more. (1) The magnetic toner for developing an electrostatic image according to (1) or (2), wherein
[0020]
(4) The magnetic toner for electrostatic image development according to (1) to (3), which contains at least one or more release agents.
[0021]
(5) The magnetic toner for developing an electrostatic image according to any one of (1) to (4), wherein the content of the release agent contained in the toner particles is 0.5 to 50% by mass.
[0022]
(6) a step of forming an electrostatic latent image on the electrostatic latent image carrier, a step of developing the electrostatic latent image with a developer layer on the developer carrier, and forming a toner image; In an image forming method including a transfer step of transferring an image onto a transfer body and a fixing step of fixing the toner image on a fixing base material surface, the toner used to form the toner image may be any of the above (1) (5) An image forming method which is the magnetic toner for developing an electrostatic image according to any of (5).
[0023]
(7) The fixing step includes a heat roll having a hollow cylindrical shape and provided with a release resin layer, and a heating member provided inside the heat roll and heating the heat roll. The image forming method according to (6), wherein the heat roll is heated to fix the toner image on the transfer material in contact with the outer peripheral surface of the heat roll.
[0024]
(8) The image forming method according to (7), wherein the release resin layer of the heat roller comprises a fluororesin layer and inorganic particles.
[0025]
(9) The image forming method according to (7), wherein the release resin layer of the heat roller is a perfluoroalkoxy alkane resin (PFA).
[0026]
(10) The image forming method according to any one of (7) to (9), wherein a process speed of the fixing step is 200 mm / s to 500 mm / s, and a diameter of the heat roll is 40 mm or less.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0028]
(Toner composition)
First, the toner composition of the present invention will be described.
[0029]
The toner of the present invention is obtained by dispersing resin particles containing a resin obtained by polymerizing a specific organic oxyacid component to a specific particle size or less, and then adjusting the particle size of the aggregated particles by coagulating the resin particles with magnetic particles. Is melted and formed into particles to produce a toner, and a magnetic toner excellent in chargeability and productivity is obtained.
[0030]
Generally, the frictional charging property of a toner often depends on the binder resin having the highest component ratio among the components constituting the toner. When the toner is manufactured by the kneading and pulverizing method, the structure of the toner surface and the shape of the toner cannot be substantially controlled, and the magnetic powder is broken at the interface between the binder resin and the magnetic powder during the pulverization. The toner tends to appear, and as a result, the charging property is unstable, and the magnetic powder detached from the toner surface damages the heat roll surface.
[0031]
On the other hand, when the toner is manufactured by the emulsion polymerization aggregation method, which is a wet manufacturing method, since the structure of the toner can be controlled, specifically, other components such as a magnetic powder and a release agent that constitute the toner are added to the toner. It can be present inside, and the contribution of these material components to charging and the amount of magnetic powder detached from the toner surface can be reduced.
[0032]
In this emulsion polymerization aggregation method, in the emulsion polymerization step, a method of dispersing and emulsifying a polymerizable monomer using a surfactant, and further adding a polymerization initiator to carry out polymerization is common. However, surfactants generally have the property of suppressing charging, which affects the charging characteristics of the toner. For example, when the amount of the surfactant added is large, the charging characteristics of the toner In a summer environment, the toner is separated from the developer because the charge is too low, so that the toner adheres to the photoreceptor, that is, so-called ground fogging occurs, and at the same time, contamination in the machine occurs. On the other hand, in a winter environment, there is a possibility that problems such as a reduction in image density due to excessive charging may occur. To prevent this, there are methods such as lengthening the toner cleaning time to reduce the amount of the remaining surfactant, but the cleaning process becomes too long, which is not only inefficient, but also increases the cost. It is not preferable.
[0033]
On the other hand, a method of producing toner particles by so-called soap-free polymerization without using a surfactant is also conceivable, but in general, particles produced by soap-free polymerization have a wide particle size distribution, and therefore the particle size distribution of the aggregated particles in the aggregation step is Control tends to be difficult. Further, in general, toner particles produced by soap-free polymerization tend to be difficult to control the shape, more specifically, to be spherical, which is not preferable.
[0034]
[Binder resin]
In the present invention, toner particles are produced by an emulsion polymerization aggregation method using a binder resin containing a polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms. The polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms has a high hydrophilicity because a large number of polar groups are contained in the condensation polymerization compound molecule. Therefore, the aggregated particles grow during the aggregation, and the polar group easily migrates to the surface of the aggregated particles, whereby the aggregated particles are easily stabilized in the aqueous medium. Therefore, in the present invention, in the emulsion polymerization aggregation method, it is possible to obtain a resin particle having a desired particle size, a narrow particle size distribution, and a desired particle shape for toner production only by adding a soap-free or a small amount of a surfactant. it can.
[0035]
Further, the surface of the toner particles that have undergone the steps of melting, cooling, washing and drying the aggregated particles are covered with the polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms. Depends on the chargeability of the resin. On the other hand, the influence on the chargeability by magnetic powder or the like in the toner can be reduced as much as possible. Furthermore, since the magnetic powder can be prevented from being exposed on the toner surface, the chargeability of the resulting toner particles is stabilized, and the desorption of the magnetic powder from the toner particle surface can be suppressed. There is no danger of damage.
[0036]
Next, the binder resin in the toner of the present invention will be described in more detail.
[0037]
As described below, the binder resin in the present invention is a binder resin containing a polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms. Binder resin containing a condensation polymerized compound of a polymerizable monomer containing an organic oxyacid ”is a compound formed by condensation polymerization of one or more organic oxyacids having 8 or less carbon atoms. A polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms and a monomer having a highly hydrophilic reactive group described below, and at least one of the above-mentioned polycondensation compounds. It includes a mixture with other resin components, and the binder resin of the present invention is at least one selected from these groups.
[0038]
As the polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms in the polycondensation compound, it is preferable to use mainly a lactic acid component of L-form or D-form. For the purpose of adjustment, a lactic acid component and another copolymerizable organic oxyacid may be used. The copolymerizable component is not particularly limited as long as it is an organic oxyacid. Specifically, glycolic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6- And hydroxycaproic acid. More preferably, glycolic acid, 3-hydroxybutyric acid, and 3-hydroxyvaleric acid are preferable because of easy adjustment of Tg and the like.
[0039]
Further, as the polycondensation compound used in the toner of the present invention, an organic oxyacid having 8 or less carbon atoms may be, for example, a homopolymer or a copolymer of the organic oxyacid listed as the copolymerizable component other than the lactic acid component. It can also be used.
[0040]
The polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms in the toner of the present invention can be polymerized by a conventionally known method. For example, it is described in JP-A-7-033861 and JP-A-59-096123.
[0041]
The polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms in the toner of the present invention is dispersed by applying a shearing force under a temperature condition of Tg or more in order to form resin particles of 1 μm or less. .
[0042]
For the above dispersion, at the time of polymerization of the binder resin, a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms and a monomer having a highly hydrophilic reactive group are copolymerized in advance, and the resin is formed. After imparting emulsifying properties, a method of high-speed stirring may be used. Alternatively, the binder resin composed of the condensation polymerization compound may be used as it is, or a method of high-speed stirring with a surfactant may be used, or a method in which the above methods are combined may be used. it can.
[0043]
Specific examples of the monomer having a highly hydrophilic reactive group which is added in advance to polymerize the binder resin to give the resin emulsification during the polymerization of the binder resin include salicylsulfonic acid and dimethyl-5-isophthalate. Examples thereof include sodium sulfonate, 4-nitrophthalic acid, and hydroquinonesulfonic acid, and salicylsulfonic acid is more preferable from the viewpoint of controlling the molecular weight of polymerization.
[0044]
The content of the monomer having a highly hydrophilic reactive group in the resin is 20% by mass or less, more preferably 10% by mass or less, and still more preferably 3% by mass or less based on the total amount of the binder resin. .
[0045]
In the production of the polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms in the toner of the present invention, a catalyst can be used, and there is no particular limitation as long as it can be polymerized. Is preferably used. More preferably, it is a divalent tin compound, specifically, stannous oxide, stannous sulfate, stannous phosphate, stannous fluoride, stannous chloride, stannous bromide, Inorganic tin compounds such as stannous iodide, stannous acetate, stannous propionate, stannous ethyl hexane, stannous carboxylate such as stannous oxalate, more preferably stannous oxide, stannous sulfate Tin, stannous chloride, stannous bromide, and stannous acetate are preferably used because of their high catalytic activity.
[0046]
The amount of the tin catalyst used is preferably 0.0001 to 5% by mass of the organic oxyacid used, more preferably 0.001 to 2% by mass, and still more preferably 0.005 to 1% by mass, The above-mentioned range is preferable from the viewpoint of easy control of polymerization. When the use amount of the tin catalyst is less than 0.0001% by mass, the effect as a catalyst is low and there is no meaning in addition, and when it exceeds 5% by mass, control of polymerization becomes difficult, which is not preferable.
[0047]
The binder resin in the present invention may be used alone as a polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms, or may be used as a mixture with another resin component. Specific examples of other resin components include styrenes such as styrene and methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, and methacryl. Esters having a vinyl group such as methyl acrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl methyl ether, vinyl isobutyl ether and the like Homopolymers such as vinyl ethers, vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketones, olefins such as ethylene, propylene, butadiene and isoprene, or a plurality of types of copolymers can be used. That.
[0048]
Further, a non-vinyl resin such as an epoxy resin, a polyester resin, a urethane resin, a polyamide resin, a cellulose resin, and a polyether resin may be mixed with the above-mentioned polycondensation compound. Two or more of these other resins may be used in combination.
[0049]
In the present invention, a slight amount of a surfactant may be used in order to produce the resin particles having a size of 1 μm or less by stirring, shearing, or the like the binder resin described above.
[0050]
Examples of the surfactant include anionic surfactants such as sulfate, sulfonate, phosphate, and soap; cationic surfactants such as amine salt and quaternary ammonium salt; polyethylene. Glycol-based, alkylphenol-ethylene oxide adduct-based, polyhydric alcohol-based and other nonionic surfactants and the like can be mentioned. Of these, ionic surfactants are preferred, and anionic surfactants and cationic surfactants are more preferred.
[0051]
In the toner of the present invention, an anionic surfactant generally has a strong dispersing power and is excellent in dispersing resin particles and a colorant, while a cationic surfactant is used as a surfactant for dispersing a release agent. Systemic surfactants are advantageous.
[0052]
The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The above-mentioned various surfactants may be used alone or in combination of two or more.
[0053]
Specific examples of the anionic surfactant include fatty acid soaps such as potassium laurate, sodium oleate, and castor oil sodium; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonylphenyl ether sulfate; lauryl Sodium alkylnaphthalenesulfonate such as sulfonate, dodecylbenzenesulfonate, triisopropylnaphthalenesulfonate, dibutylnaphthalenesulfonate, naphthalenesulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric amide sulfonate, oleic amide sulfonate, etc. Sulfonates: lauryl phosphate, isopropyl phosphate, nonylphenyl ether Phosphoric acid esters such as phosphate; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate, sulfosuccinic acid salts, such as sodium lauryl sulfosuccinate 2; and the like.
[0054]
Specific examples of the cationic surfactant include amine salts such as laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate; lauryltrimethylammonium chloride, dilauryldimethyl. Ammonium chloride, distearyl ammonium chloride, distearyl dimethyl ammonium chloride, lauryl dihydroxyethyl methyl ammonium chloride, oleyl bis polyoxyethylene methyl ammonium chloride, lauroyl aminopropyl dimethyl ethyl ammonium ethosulfate, lauroyl amino propyl dimethyl hydroxy ethyl ammonium perchlorate, alkyl benzene Dimethyl ammonium chloride, alkyl Quaternary ammonium salts such as trimethyl ammonium chloride; and the like.
[0055]
Specific examples of the nonionic surfactant include alkyl ethers such as polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether; Alkyl phenyl ethers such as oxyethylene nonylphenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, and polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxy Alkylamines such as ethylene oleyl amino ether, polyoxyethylene soybean amino ether and polyoxyethylene tallow amino ether; poly Alkyl amides such as xylethylene lauric amide, polyoxyethylene stearamide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether and polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearin Alkanolamides such as acid diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmiate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monooleate And the like.
[0056]
The surfactant can be preferably used because an anionic surfactant has excellent dispersing power. More preferably, sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, nonylphenyl ether sulfate; sodium alkylnaphthalene sulfonate such as lauryl sulfonate, dodecylbenzene sulfonate, triisopropylnaphthalene sulfonate, dibutyl naphthalene sulfonate, and naphthalene sulfonate formalin Condensates, more preferably lauryl sulfonate, dodecylbenzene sulfonate, and triisopropylnaphthalene sulfonate.
[0057]
The content of each of the surfactants in each dispersion may be an amount that does not impair the present invention, and is generally small, and specifically, in the case of the resin particle dispersion, 0.01 to It is about 3% by mass, more preferably about 0.02 to 1% by mass, and still more preferably about 0.1 to 0.5% by mass. When the content is less than 0.01% by mass, the effect on dispersion may not be exhibited, and when the content is more than 3% by mass, washing of the toner becomes difficult and charge control becomes difficult, which is not preferable.
[0058]
The production of the resin particles is not particularly limited as long as the resin particles can be sheared at a high speed at a temperature equal to or higher than the Tg of the resin. Specific examples include an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a Menton, a Gaulin homogenizer and a pressure homogenizer, and a medium disperser such as a sand grinder, a Getzman mill and a diamond fine mill. More preferably, a pressure disperser such as a Gaulin homogenizer or a pressure type homogenizer is excellent in terms of particle size control.
[0059]
[Magnetic powder]
As the magnetic fine powder used in the present invention, known magnetic substances, for example, metals such as iron, cobalt, nickel and alloys thereof, Fe ₃ O ₄ , Γ-Fe ₂ O ₃ Metal oxides such as cobalt-added iron oxide, various ferrites such as MnZn ferrite and NiZn ferrite, magnetite, hematite and the like can be used, and their surfaces may be treated with a silane coupling agent or a titanate coupling agent.
[0060]
When these magnetic fine powders are contained, the mixing ratio is preferably in the range of 10 to 70% by weight, more preferably in the range of 15 to 50% by weight, based on the whole toner particles. If the amount of the magnetic fine powder is less than 10% by weight, the binding force of the magnet of the toner carrier is reduced, and the problem of toner scattering occurs. If it exceeds 70% by weight, there is a problem that the reproducibility of the concentration is reduced.
[0061]
[Colorant]
In addition, a colorant can be used in combination for color adjustment and the like. As the colorant, any known colorants used in toners can be used. For example, carbon black, organic pigments and dyes can be used as appropriate.
[0062]
[Release agent]
A release agent can be added to the toner used in the present invention. By adding the release agent, the toner can be released from the fixing member without applying silicone oil to the fixing device, and at the same time, the fixing device can be reduced in size and weight because the oil supply device is eliminated. .
[0063]
When the emulsion aggregation coalescence method, which is a method for producing a toner in the present invention, is used, the generally release agent, which is generally hydrophobic, is drawn into the inside of the particles at the time of aggregation and coalescence, so that it is unlikely to be present on the toner surface. Since it is presumed that a large amount of a polycondensation compound of a polymerizable monomer containing a more hydrophilic organic oxyacid having 8 or less carbon atoms is present on the surface as described above, the formation of particles in the emulsion aggregation coalescence method is considered. Is easy.
[0064]
Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleamide, erucamide, ricinoleamide, and stearamide. Vegetable waxes such as carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Mineral and petroleum waxes; ester waxes of higher fatty acids such as stearyl stearate and behenyl behenate and higher alcohols; butyl stearate, propyl oleate, glyceride monostearate, diste Ester waxes of higher fatty acids such as glyceride phosphate and pentaerythritol tetrabehenate with unit prices or polyhydric lower alcohols; higher grades such as diethylene glycol monostearate, dipropylene glycol distearate, distearic diglyceride and tetrastearic triglyceride Ester waxes composed of a fatty acid and a polyhydric alcohol polymer; sorbitan higher fatty acid ester waxes such as sorbitan monostearate; and cholesterol higher fatty acid ester waxes such as cholesteryl stearate. In the present invention, these release agents may be used alone or in combination of two or more.
[0065]
The addition amount of these release agents is preferably 0.5 to 50% by mass, more preferably 1 to 30% by mass, and even more preferably 2 to 15% by mass. When the amount is less than 0.5% by mass, the effect of the release agent addition is not obtained, and when the amount is 50% by mass or more, the chargeability is likely to be affected, or the release agent released during the production is present. This is not desirable because it causes defects such as filming on the carrier and the photosensitive drum.
[0066]
Of the release agents in the present invention, preferably polyethylene, polypropylene, low molecular weight polyolefins such as polybutene, carnauba wax, rice wax, candelilla wax, wood wax, vegetable wax such as jojoba oil, beeswax and the like. Mineral and petroleum waxes such as animal wax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and ester waxes of higher fatty acids such as stearyl stearate and behenyl behenate and higher alcohols. And more preferably low-molecular-weight polyolefins such as polyethylene, polypropylene and polybutene, carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil and other vegetable waxes. And ester waxes of higher fatty acids, such as stearyl stearate and behenyl behenate, and higher alcohols enter between the heating member of the fixing machine and the toner image surface in a short time by heating the toner to have a releasing effect. Therefore, it is preferably used.
[0067]
[Other additives]
In the present invention, other components (particles) such as a charge controlling agent, inorganic particles, organic particles, a lubricant, and an abrasive are added according to the purpose, in addition to the resin, the colorant, and the release agent. It is possible to do.
[0068]
The charge control agent is not particularly limited, but when a color toner is used, a colorless or light-colored one can be preferably used. For example, a quaternary ammonium salt compound, a nigrosine compound, a dye composed of a complex of aluminum, iron, chromium, and the like, a triphenylmethane pigment, and the like can be given.
[0069]
Examples of the inorganic particles include all particles usually used as an external additive on the toner surface, such as silica, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, and cerium oxide.
[0070]
Examples of the organic particles include all particles usually used as an external additive on the toner surface, such as a vinyl resin, a polyester resin, and a silicone resin. In addition, these inorganic or organic particles, a fluidity aid, a cleaning aid, and the like can be used.
[0071]
Examples of the lubricant include fatty acid amides such as ethylenebisstearic acid amide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate.
[0072]
Examples of the abrasive include the above-mentioned silica, alumina, cerium oxide and the like.
[0073]
In the present invention, as a fluidity improver, polymethyl methacrylate (PMMA), nylon, melamine, benzoguanamine, fluorine-based spherical particles, or various known particles are used as a resin powder on the surface of the obtained toner for developing an electrostatic image. Inorganic compounds such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , MgO, CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO ・ SiO ₂ , CaCO ₃ , K ₂ O (TiO ₂ ) N, MgCO ₃ , Al ₂ O ₃ ・ 2SiO ₂ , BaSO ₄ , MgSO ₄ And the like, preferably SiO 2 ₂ , TiO ₂ , Al ₂ O ₃ However, the present invention is not limited thereto, and one kind or two or more kinds may be used in combination. The particle size of the fluidity improver is preferably 0.1 μm or less, and the amount of the fluidity improver as an external additive is in the range of 0.1 to 20% by weight based on the toner particles. be able to.
[0074]
(Emulsion polymerization aggregation method)
The emulsion polymerization aggregation method, which is a method for producing the toner of the present invention, comprises mixing a resin particle dispersion in which resin particles of at least 1 μm or less are dispersed, and a colorant dispersion in which a colorant is dispersed. (Hereinafter sometimes referred to as “aggregation step”), and heated to a temperature equal to or higher than the glass transition point of the resin to fuse the aggregates to form colored toner particles (hereinafter referred to as “fusion step”). May be included).
[0075]
In the aggregation step, the resin particles in the resin particle dispersion liquid, the colorant dispersion liquid, and, if necessary, the resin particles in the release agent dispersion liquid are aggregated to form aggregated particles. The agglomerated particles are formed by heteroaggregation or the like, and for the purpose of stabilizing the agglomerated particles and controlling the particle size / particle size distribution, an ionic surfactant having a different polarity from the agglomerated particles, or a monovalent or more monovalent metal salt or the like It is formed by adding a compound having a charge.
[0076]
In the fusing step, the resin in the agglomerated particles is melted at a temperature equal to or higher than the glass transition point.
[0077]
In the aggregation step in the preparation of the toner according to the present invention, aggregated particles can be generated by changing the pH to adjust the particle diameter of the particles. At the same time, a flocculant may be added as a method for stably and rapidly aggregating the particles or for obtaining agglomerated particles having a narrower particle size distribution.
[0078]
As the coagulant, a compound having a charge of monovalent or more is preferable. Specific examples of the compound having a charge of monovalent or more as the coagulant include water-soluble surfactants such as the aforementioned ionic surfactants and nonionic surfactants. Activators, acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and oxalic acid; metal salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, and sodium carbonate; Metal salts of aliphatic acids and aromatic acids such as sodium acetate, potassium formate, sodium oxalate, sodium phthalate and potassium salicylate, metal salts of phenols such as sodium phenolate, metal salts of amino acids, and triethanolamine hydrochloride And inorganic acid salts of aliphatic and aromatic amines such as aniline hydrochloride.
[0079]
More preferably, metal salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, and sodium carbonate, sodium acetate, potassium formate, sodium oxalate, sodium phthalate, and salicylic acid It is an inorganic or organic metal salt such as an aliphatic acid such as potassium, and more preferably a polyvalent inorganic metal salt such as aluminum sulfate, aluminum nitrate, aluminum chloride, or magnesium chloride is used for the stability of agglomerated particles and the heat of an aggregating agent. And stability with time, removal during washing, and the like.
[0080]
The amount of the coagulant added depends on the valence of the charge, but is small in each case, about 3% by weight or less for monovalent, about 1% by weight or less for divalent, and about 3% by weight for trivalent. Is about 0.5% by weight or less. Since a smaller amount of the coagulant is preferable, a compound having a higher valence is preferable.
[0081]
The volume average particle diameter of the toner according to the present invention manufactured by the above-described manufacturing method is preferably 3 to 10 μm from the viewpoint of obtaining image quality. More preferably, it is 3 to 8 μm, and still more preferably, 4 to 7 μm. When the particle diameter is 10 μm or more, the reproducibility of fine lines is inferior in the developing step, so that the image quality is reduced. When the particle diameter is 3 μm or less, the chargeability of the developer is reduced, and the life is shortened. Absent.
[0082]
The particle size distribution of the toner in the present invention is calculated from the number average particle size and is represented by the following equation.
[0083]
(Equation 1)
Particle size distribution = {(d84 / d50) + (d50 / d16)} / 2
Here, d16, d50, and d84 are 16%, 50%, and 84% diameter, respectively, when integrated from the small particle size side of the toner.
[0084]
The particle size distribution is preferably from 1.13 to 1.30 from the viewpoint of maintaining high image quality. There is a certain range in the particle diameter of the toner, and when the toner is used in a developing machine, the toner having a specific particle diameter tends to be more easily developed. Specifically, a toner having a large particle diameter is more likely to be developed, so that a toner having a small particle diameter remains in the developing device, and the toner having a small particle diameter gradually increases by adding toner. Although the image quality is initially satisfactory, it is thought that there is less toner to be developed with an increase in the number of copies, which tends to cause problems such as a decrease in density and ground fogging in which the toner is developed on a blank portion of the document. Can be
[0085]
The particle size distribution is more preferably 1.13 or more and 1.26 or less, and still more preferably 1.13 or more and 1.24 or less.
[0086]
When the particle size distribution exceeds 1.30, the particle size distribution is wide and the charging property of the toner over time cannot be maintained as described above. Since it is necessary to control the particle size distribution of the resin particles and to classify the produced toner particles, the process becomes complicated, which is not preferable.
[0087]
The method for producing a toner for developing an electrostatic image of the present invention comprises preparing a resin by emulsion polymerization, heteroaggregating the resin with a dispersion of a pigment, a release agent, and the like, and uniting the resultant at a temperature equal to or higher than the glass transition point. Further, a pigment, a release agent, etc. are dispersed in a polymerizable monomer, polymerized after granulation, and a toner is obtained.For example, a magnetic powder or a release agent is used as a nucleus to perform seed polymerization or the like. There is no problem even if the obtained colored magnetic resin particles, release agent-encapsulated resin particles, and the like are heteroaggregated and united.
[0088]
The absolute value of the charge amount of the electrostatic image developing toner is preferably from 10 to 40 μC / g, more preferably from 15 to 35 μC / g. If the charge amount is less than 10 μC / g, background stains are likely to occur, and if it exceeds 40 μC / g, the image density tends to decrease. Since the organic photoreceptor is used for reversal development, it is desirable that the photoreceptor has a negative charge.
[0089]
The surface area of the toner for developing an electrostatic image of the present invention is not particularly limited, and may be used as long as it can be used for ordinary toner. Specifically, when using the BET method, 0.5 to 10 m ² / G, preferably 1.0 to 7 m ² / G, more preferably 1.2 to 5 m ² / G.
[0090]
The magnetic toner of the present invention may be used together with a carrier and used as a magnetic two-component developer.
[0091]
The carrier is not particularly limited and includes known carriers per se. For example, known carriers such as resin-coated carriers described in JP-A-62-39879, JP-A-56-11461, and the like. Can be used.
[0092]
Specific examples of the carrier include the following resin-coated carriers. That is, examples of the core particles of the carrier include ordinary iron powder, ferrite, and a molded product of magnetite, and the average diameter thereof is about 30 to 200 μm. Ferrite is preferred as the core particles from the viewpoint of high image quality.
[0093]
For the production of the carrier, a heated kneader, a heated Henschel mixer, a UM mixer, or the like can be used, and depending on the amount of the coating resin, a heated fluidized bed, a heated kiln, or the like can be used. it can.
[0094]
(Image forming method)
The image forming method using the toner of the present invention includes an electrostatic latent image forming step, a toner image forming step, a transfer step, and a fixing step.
[0095]
The heat roll fixing device used in the fixing step of the image forming method according to the present invention will be described with reference to FIG.
[0096]
FIG. 1 is a side sectional view illustrating an example of a configuration of a main part of the heat roller fixing device. As shown in FIG. 1, the apparatus is for fixing a toner image 11 on a transfer material 10 by using heat, and is provided with a hollow cylindrical heat roll 1 and an inside of the heat roll 1. A heating member 2 for heating the heat roll, a temperature sensor 3 installed near the outer peripheral surface of the heat roll 1 to detect the temperature of the outer peripheral surface, and a pressure disposed opposite to the heat roll 1. It is composed of rollers 4.
[0097]
The fixing device of the present invention may be of a roll type as shown in FIG. 1 or a belt type as opposed to the heat roll.
[0098]
The heat roll 1 is made of a material such as aluminum or nickel, which has at least sufficient heat resistance at a temperature required for fixing an unfixed image, and is also excellent in heat conductivity, workability, and economy. A release resin layer 5 for preventing the offset phenomenon of the toner image 11 is provided, and 3 to 15% by weight of inorganic particles having a particle diameter of 1 to 4 μm is added to the release resin layer 5. When the inorganic particle diameter is 4 μm or more, when the fixing of more than 50,000 sheets is performed, when the inorganic particles are detached due to the abrasion of the fluororesin layer around the inorganic particles, the small-diameter toner is buried in the detached holes, and paper or other Cannot be removed by contact with the toner, and the generation of NVO cannot be prevented even if the releasability of the toner from the heat roll is improved. On the other hand, when the thickness is less than 1 μm, the inorganic particles are easily detached, so that a sufficient performance as a wear-resistant material cannot be exhibited.
[0099]
As the above-mentioned inorganic particles, SiC, ceramic, TiO ₂ Although SiC is preferred, SiC is preferred from the viewpoint of releasability from the toner.
[0100]
The resin used for the release resin layer 5 is, for example, silicone rubber, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, a copolymer of tetrafluoroethylene and ethylene, and a copolymer of tetrafluoroethylene and hexafluoroethylene. And a fluororesin such as a perfluoroalkoxyalkane resin (PFA), and more preferably PFA.
[0101]
The inner peripheral surface of the heat roll 1 is coated with a temperature indicating member 6 that reversibly changes according to the temperature so that the heat reflectance increases at high temperatures and decreases at low temperatures.
[0102]
The heating member 2 is formed of, for example, a Colt lamp or a ceramic heater, and is connected to an electric circuit (not shown) for controlling the heating state based on the outer peripheral surface temperature of the heat roll 1 detected by the temperature sensor 3.
[0103]
The temperature sensor 3 is formed by a thermosensitive resistance element such as a thermocouple or a thermistor. The pressure roller 4 is formed of, for example, a metal core roll covered with silicon rubber or the like, and is arranged so that the transfer material 10 can pass between the pressure roller 4 and the heat roll 1.
[0104]
The process speed of the fixing step in the present invention is preferably from 200 mm / s to 500 mm / s, and the diameter of the heat roll is preferably 40 mm or less. If the process speed of the fixing step is less than 200 mm / s, there is a disadvantage that the speed cannot be increased, while if it exceeds 500 mm / s, the curvature of the roll may be large when the diameter of the heat roller is 40 mm or less. There is an inconvenience that the contact time is short and the amount of heat required for fixing is difficult to obtain. In addition, the thickness of the heat roller is reduced to enable fixing in a short time from the time of waiting for printing, but when the diameter of the heat roller exceeds 40 mm, the strength is insufficient and a uniform load is not applied to the fixed image. There are inconveniences.
[0105]
【Example】
Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.
[0106]
In the following, “parts” means parts by mass. The average particle size of the toner was measured using a Coulter counter (TA2 type, manufactured by Beckman Coulter, Inc.).
[0107]
-Preparation of resin particle dispersion (1)-
Lactic acid 360 parts
760 parts of diphenyl ether
1.5 parts stannous oxide
(Wako Pure Chemical Co., Ltd.)
After mixing the above and charging the mixture in a nitrogen gas atmosphere, the pressure inside the system was reduced to 120 mmHg (16.0 kPa), and the temperature was gradually increased to 135 ° C. While maintaining the temperature at 135 ° C., the pressure inside the system was reduced to 50 mmHg (6.7 kPa), and the system was left for 3 hours. The system was further left at 135 ° C. and 25 mmHg (3.3 kPa) for 3 hours without delay. Stirred. Thereafter, the mixture was allowed to stand at 135 ° C. and 25 mmHg for further 24 hours, and then returned to room temperature and normal pressure to obtain a resin (1).
[0108]
100 parts of this resin, 300 parts of ion-exchanged water and 2.5 parts of an anionic surfactant (manufactured by NOF CORPORATION: NUREX R (registered trademark)) were stirred, and a pressure dispersing machine (manufactured by Doei Shoji Co., Ltd .: Gorin) 130 ° C., 500 kg / cm using a homogenizer (registered trademark)) ² For 1 hour, and after cooling, a resin particle dispersion liquid (1) was obtained.
[0109]
-Preparation of resin particle dispersion (2)-
100 parts of lactic acid
200 parts of 3-hydroxybutyric acid
760 parts of diphenyl ether
Stannous chloride 2.1 parts
(Wako Pure Chemical Co., Ltd.)
After mixing the above and charging the mixture in a nitrogen gas atmosphere, the pressure in the system was reduced to 120 mmHg, and the temperature was gradually increased to 130 ° C. The temperature was raised to 140 ° C., the pressure inside the system was reduced to 50 mmHg, and the system was left for 3 hours. The system was further left without delay at 140 ° C. and 25 mmHg for 3 hours, and heated and stirred while flowing out of the system. Thereafter, the mixture was allowed to stand at 135 ° C. and 25 mmHg for further 24 hours, and then returned to room temperature and normal pressure to obtain a resin (2).
[0110]
100 parts of this resin, 300 parts of ion-exchanged water and 2.5 parts of an anionic surfactant (manufactured by NOF CORPORATION: NUREX R (registered trademark)) were stirred, and a pressure dispersing machine (manufactured by Doei Shoji Co., Ltd .: Gorin) 130 ° C., 500 kg / cm using a homogenizer (registered trademark)) ² For 1 hour, and after cooling, a resin particle dispersion (2) was obtained.
[0111]
-Preparation of resin particle dispersion (3)-
82.6 parts of styrene
9.2 parts of n-butyl acrylate
1.3 parts of acrylic acid
0.4 parts of hexanediol acrylate
3.2 parts of n-lauryl mercaptan
(Wako Pure Chemical Co., Ltd.)
An oil layer obtained by mixing and dissolving the above and a water layer obtained by dissolving 1.5 parts of NUREX R (manufactured by NOF CORPORATION) in 150 parts of ion-exchanged water are mixed and dispersed in a flask, and slowly stirred for another 10 minutes. After mixing, 10 parts of ion-exchanged water in which 0.15 part of potassium persulfate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved was added. After sufficient replacement with nitrogen, the contents of the flask were heated in an oil bath until the temperature of the flask reached 70 ° C. while stirring, and emulsion polymerization was continued for 6 hours. Thereafter, the reaction solution was cooled to room temperature to prepare a resin particle dispersion (3).
[0112]
-Preparation of magnetic powder dispersion (1)-
100 parts of magnetic powder (trade name: MTH009F, manufactured by Toda Kogyo)
2.0 parts of anionic surfactant
(Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK)
300 parts of ion exchange water
After mixing and dissolving the above, the mixture was dispersed using a homogenizer (Ultra Turrax manufactured by IKA) to prepare a magnetic powder dispersion liquid (1) in which the magnetic powder was dispersed.
[0113]
-Preparation of release agent dispersion liquid (1)-
80 parts of polyethylene wax
(Toyo Petrolite Co., Ltd .: Polywax 725)
1.0 part of anionic surfactant
(Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK)
120 parts of ion exchange water
After mixing and dissolving the above at 95 ° C., the mixture was dispersed using a homogenizer (Ultra Turrax manufactured by IKA) to prepare a release agent dispersion liquid (1) in which polyethylene wax was dispersed.
[0114]
-Career creation example-
100 parts of ferrite particles (manufactured by Powder Tech, average particle size: 50 μm), 1.0 part of methyl methacrylate resin (manufactured by Mitsubishi Rayon Co., molecular weight: 51,000), and 3.0 parts of silicone resin (manufactured by Shin-Etsu Chemical: KR255 (registered trademark)) 3.0 The mixture was placed in a pressurized kneader together with 400 parts of toluene, stirred and mixed at room temperature for 15 minutes, heated to 70 ° C. while mixing under reduced pressure, toluene was distilled off, and further stirred and mixed at 130 ° C. for 1 hour. After cooling, the particles were sized using a 105 μm sieve to produce a ferrite carrier (resin-coated carrier).
[0115]
[Example 1]
<Aggregation step>
-Preparation of aggregated particles-
60.0 parts of resin particle dispersion liquid (1)
170.0 parts of resin particle dispersion liquid (3)
Magnetic powder dispersion (1) 15.0 parts
Release agent particle dispersion (1) 17.5 parts
632.5 parts of ion exchange water
Aluminum sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) 1.3 parts
The above was placed in a round stainless steel flask, and dispersed using a homogenizer (IKA: Ultra Turrax T50). The pH in the container was adjusted to 3.3, and the mixture was placed in a heating oil bath. Heat to 53 ° C. with stirring. After maintaining at 53 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles having an average particle size of about 5.8 μm were formed. 30.0 parts of the resin particle dispersion liquid (1) was gently added to the aggregated particle dispersion liquid, and the mixture was further heated and stirred at 53 ° C. and a pH of 3.3 for 30 minutes, and then observed with an optical microscope. As a result, it was confirmed that aggregated particles having an average particle size of about 6.3 μm were formed.
[0116]
<Fusion process>
The pH of the aggregated particles was 3.2. Therefore, an aqueous solution of sodium hydroxide (manufactured by Wako Pure Chemical Industries) diluted to 0.5% by mass was gently added, the pH was adjusted to 6.8, and the mixture was heated to 96 ° C. while stirring was continued. Hold for 5 hours.
[0117]
Thereafter, the pH in the container was adjusted to about 7, the reaction product was filtered, washed four times with 500 parts of ion-exchanged water, and dried using a vacuum dryer to obtain a toner.
[0118]
<Evaluation>
The weight average particle size of the obtained toner was 6.5 μm. To 100 parts of the obtained toner particles, 1.5 parts of colloidal silica (R972, manufactured by Nippon Aerosil Co., Ltd.) was externally added and mixed using a Henschel mixer to obtain a toner for developing an electrostatic image developing magnetic toner (1). ) Got.
[0119]
The number particle size and d50 of this toner were 5.41 μm and the particle size distribution was 1.22.
[0120]
A fixing process using a modified machine of Fuji Xerox "Laser Press 4161II" (registered trademark) in which a fluorine resin layer is provided on the surface of a heat roll having a diameter of 35 mm and 4.2% of SiC particle diameter is added by 4.2%. A running test of 200,000 sheets was performed by intermittent running in which one sheet was printed and waited for one minute under high temperature and high humidity so that the speed was 220 mm / s, and the surface of the fixing roll was observed. Further, the offset occurrence temperature was evaluated using S paper manufactured by Fuji Xerox Co., Ltd.
[0121]
In the summer environment (temperature 30 ° C., humidity 90%) and the winter environment (temperature 10 ° C., humidity 10%), the image quality of the text portion and the background portion of the first and 10,000th images were visually evaluated.
[0122]
[Example 2]
<Aggregation step>
-Preparation of aggregated particles-
260.0 parts of resin particle dispersion liquid (2)
Magnetic powder dispersion (1) 16.0 parts
Release agent particle dispersion (1) 20.5 parts
632.5 parts of ion exchange water
1.3 parts of aluminum chloride (manufactured by Wako Pure Chemical Industries, Ltd.)
The above was accommodated in a round stainless steel flask, and dispersed using a homogenizer (manufactured by IKA: Ultra Turrax T50 (registered trademark)). The pH in the container was adjusted to 3.5, and the mixture was heated. The mixture was heated with stirring to 55 ° C. in an oil bath. After maintaining at 55 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles having an average particle size of about 6.3 μm were formed. 30.0 parts of the resin particle dispersion liquid (2) is gently added to the aggregated particle dispersion liquid, and the mixture is further heated and stirred at 55 ° C. and pH 3.5 for 40 minutes, and then observed with an optical microscope. As a result, it was confirmed that aggregated particles having an average particle size of about 6.8 μm were formed.
[0123]
<Fusion process>
The pH of the aggregated particles was 3.5. Therefore, an aqueous solution of sodium hydroxide (manufactured by Wako Pure Chemical Industries) diluted to 0.5% by mass was gently added, the pH was adjusted to 6.8, and the mixture was heated to 96 ° C. while stirring was continued. Hold for 5 hours.
[0124]
Thereafter, the pH in the container was adjusted to about 7, the reaction product was filtered, washed four times with 500 parts of ion-exchanged water, and dried using a vacuum dryer to obtain a toner.
[0125]
<Evaluation>
The weight average particle diameter of the obtained toner was 6.7 μm. To 100 parts of the obtained toner particles, 1.7 parts of colloidal silica (R972, manufactured by Nippon Aerosil Co., Ltd.) was externally added and mixed using a Henschel mixer to obtain a magnetic toner for electrostatic image development (2). Got.
[0126]
The number particle size and d50 of the toner were 5.62 μm and 1.24, respectively.
Using a modified machine of “Laser Press 4161II” (registered trademark) manufactured by Fuji Xerox Co., Ltd. using a PFA tube on the surface of a heat roll having a diameter of 35 mm, the fixing process speed was set to 280 mm / s, and Similarly, a running test and image quality evaluation were performed.
[0127]
[Example 3]
The magnetic toner (1) for developing an electrostatic charge image used in Example 1 and the ferrite carrier were mixed to prepare a magnetic two-component developer (1) having a toner concentration of 7% by weight.
[0128]
Further, using a copier made by Fuji Xerox Co., Ltd. (Fuji Xerox Co., Ltd .: Vivace400 (registered trademark) modified machine) using a PFA tube on the surface of a heat roll having a diameter of 38 mm, the fixing process speed was set to 420 mm / s. A running test and image quality evaluation were performed in the same manner as in Example 1.
[0129]
[Comparative Example 1]
<Aggregation step>
-Preparation of aggregated particles-
230.0 parts of resin particle dispersion liquid (3)
Magnetic powder dispersion (1) 15.0 parts
Release agent particle dispersion (1) 17.5 parts
632.5 parts of ion exchange water
Aluminum sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) 1.3 parts
The above was placed in a round stainless steel flask, and dispersed using a homogenizer (IKA: Ultra Turrax T50). The pH in the container was adjusted to 3.3, and the mixture was placed in a heating oil bath. Heat to 53 ° C. with stirring. After maintaining at 53 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles having an average particle size of about 6.0 μm had been formed. 30.0 parts of the resin particle dispersion liquid (1) is gently added to the aggregated particle dispersion liquid, and the mixture is further heated and stirred at 53 ° C. and a pH of 3.3 for 30 minutes, and then observed with an optical microscope. As a result, it was confirmed that aggregated particles having an average particle size of about 6.5 μm were formed.
[0130]
<Fusion process>
The pH of the aggregated particles was 3.2. Therefore, an aqueous solution of sodium hydroxide (manufactured by Wako Pure Chemical Industries) diluted to 0.5% by mass was gently added, the pH was adjusted to 6.8, and the mixture was heated to 96 ° C. while stirring was continued. Hold for 5 hours.
[0131]
Thereafter, the pH in the container was adjusted to about 7, the reaction product was filtered, washed four times with 500 parts of ion-exchanged water, and dried using a vacuum dryer to obtain a toner.
[0132]
<Evaluation>
The weight average particle size of the obtained toner was 6.5 μm. To 100 parts of the obtained toner particles, 1.5 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd., R972) was externally added, and mixed using a Henschel mixer, to thereby prepare a toner for electrostatic image developing magnetic toner (3). Got.
[0133]
The number particle size and d50 of this toner were 5.39 μm and the particle size distribution was 1.20.
[0134]
A fixing process using a modified machine of "Laser Press 4161II" (registered trademark) manufactured by Fuji Xerox, in which a fluorine resin layer is provided on the surface of a heat roll having a diameter of 35 mm and 4.2% of SiC particle diameter is added by 4.2%. A running test and image quality evaluation were performed in the same manner as in Example 1 so that the speed became 220 mm / s.
[0135]
[Comparative Example 2]
<Kneading and crushing classification process>

The above-mentioned material was powder-mixed by a Henschel mixer, and the mixture was kneaded by an extruder (melt viscosity of the material at the time of kneading: MI 16.5 g / 10 min) at a set temperature of 140 ° C. After cooling, the mixture was roughly pulverized and finely pulverized to obtain a pulverized product having a 50% volume diameter D50 of 6.9 μm. Further, the weight average particle size of the toner obtained by classifying the pulverized product was 6.5 μm. To 100 parts of the obtained toner particles, 1.5 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd., R972) was externally added, and mixed using a Henschel mixer to obtain a toner for electrostatic image developing magnetic toner (4). Got.
[0136]
The number particle size and d50 of this toner were 4.56 μm and the particle size distribution was 1.31.
The obtained magnetic toner was subjected to centrifugal separation, and the amount of free magnetic powder was measured to be 0.06 vol%.
[0137]
As in Example 1 in which a fluorine resin layer was provided on the surface of a heat roll having a diameter of 35 mm and 4.2% of SiC particle diameter of 2.4 μm was added, a modified machine of “Laser Press 4161II” (registered trademark) manufactured by Fuji Xerox Co., Ltd. was used. A running test and an image quality evaluation were performed in the same manner as in Example 1 so that the fixing process speed was 220 mm / s.
[0138]
[Table 1]

[0139]
(Evaluation criteria)
The presence or absence of the occurrence of an offset at 180 ° C. was confirmed. The case where there was no offset was indicated by “○”, and the case where an offset occurred was indicated by “×”. In addition, the heat roll stains, after printing 200,000 sheets, visually check the presence or absence of stains on the heat roll surface, if the stain was not found visually, "○", on the other hand, if the stain was found visually “×” was assigned.
[0140]
As is clear from the above results, the chargeability of the developers prepared in Examples 1 to 3 is higher in the summer environment than the chargeability of the developer prepared in Comparative Examples 1 and 2. For the development of electrostatic charge images, there is little environmental difference in the amount of charge in the winter environment, prevents fouling of the fixing heat rolls caused by magnetic powder released even after continuous operation of 200,000 sheets, and does not adversely affect the fixing device for a long time. A toner and an electrostatic image developer were obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a fixing device used in a fixing step of an image forming method of the present invention.
[Explanation of symbols]
Reference Signs List 1 heat roller, 2 heating member, 3 temperature sensor, 4 pressure roller, 5 release resin layer, 6 temperature indicating member, 10 transfer material, 11 toner image.

Claims (3)

In a toner produced by a wet process, the toner is a magnetic toner for electrostatic image development, comprising a binder resin containing a polycondensation compound of a polymerizable monomer containing an organic oxyacid having 8 or less carbon atoms and a magnetic powder. . Forming an electrostatic latent image on the electrostatic latent image carrier, developing the electrostatic latent image with a developer layer on the developer carrier to form a toner image, and transferring the toner image A transfer step of transferring onto a body, and an image forming method including a fixing step of fixing the toner image on a fixing base material surface,
An image forming method, wherein the toner used for forming the toner image is the magnetic toner for electrostatic image development according to claim 1. The fixing step includes a heat roll provided with a release resin layer in a hollow cylindrical shape, and a heating member provided inside the heat roll to heat the heat roll,
The image forming method according to claim 2, wherein the heat roller is heated by the heating member to fix the toner image on the transfer material in contact with the outer peripheral surface of the heat roll.

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