JP3643995B2 - Toner for developing electrostatic image, developer and image forming method - Google Patents

Description

【００８７】
【表２】

【００８８】
評価
上記トナーをスチレン−アクリル樹脂で被覆した体積平均粒径が５０μｍのフェライトキャリアと混合し、トナー濃度が７重量％の現像剤を調整して使用した。
【００８９】
なお、上記「トナー１」〜「トナー９」及び「比較用トナー１」〜「比較用トナー４」に対応する現像剤を「現像剤１」〜「現像剤９」及び「比較用現像剤１」〜「比較用現像剤４」とする。
【００９０】
（接触現像方式）
コニカ社製複写機ＫｏｎｉｃａＵ−ＢＩＸ３１３５を使用して評価を行った。なお、現像剤層厚は１．５ｍｍ、感光体と現像剤担持体（現像スリーブ）の間隙（Ｄｓｄ）は０．５ｍｍである。
【００９１】
評価条件は低温低湿（１０℃、１０％ＲＨ）環境下で１万枚連続印字後、２４時間放置し印字を繰り返す方法で６万枚まで印字を行ない、休止後の最初の画像に発生するカブリ濃度を測定した。結果を下記表３に示す。
【００９２】
なお、カブリ濃度は紙の濃度を０とした相対濃度で、マクベス濃度計（ＲＤ−９１８）で測定される。また、評価には「現像剤１」、「現像剤４」、「現像剤５」及び「比較用現像剤１」を使用した。
【００９３】
【表３】

【００９４】
本発明内の「現像剤１」、「現像剤４」、「現像剤５」は６万枚まで印字しても、ほとんどかぶりの増加が無いのに対し「比較用現像剤１」では、初期には良好であるが、次第に増加していくことがわかる。
【００９５】
（非接触現像方式）
評価は、非接触現像方式で一括転写方式のコニカ社製カラー複写機Ｋｏｎｉｃａ９０２８を改造して使用した。条件は下記に示す条件である。感光体としては積層型有機感光体を使用した。
【００９６】
感光体表面電位＝−５５０Ｖ
ＤＣバイアス ＝−２５０Ｖ
ＡＣバイアス ＝Ｖｐ−ｐ：−５０〜−４５０Ｖ
交番電界周波数＝１８００Ｈｚ
Ｄｓｄ ＝３００μｍ
押圧規制力 ＝１０ｇｆ／ｍｍ
押圧規制棒 ＝ＳＵＳ４１６（磁性ステンレス製）／直径３ｍｍ
現像剤層厚 ＝１５０μｍ
現像スリーブ ＝２０ｍｍ
なお、現像剤は「現像剤１」〜「現像剤４」、「現像剤６」〜「現像剤９」及び「比較用現像剤１」〜「比較用現像剤４」を各々組み合わせてフルカラー現像剤として使用した。
【００９７】
評価方法はフルカラーで画素率が７５％の画像を用い、高温高湿環境（３３℃、８０％ＲＨ）にて印字を実施した。印字は１０００枚連続印字を行い、ついで２４時間放置し印字を継続する方式で１万枚まで実施し、転写ムラの発生した枚数を記録した。
【００９８】
評価結果を下記表に示す。
【００９９】
【表４】

【０１００】
本発明内の「現像剤１」〜「現像剤４」、「現像剤６」〜「現像剤９」を用いたものは何ら問題が無いのに対し、本発明外の「比較用現像剤１」〜「比較用現像剤４」を組み合わせて用いたものは、十分な特性を持っていないことがわかる。
【０１０１】
尚、図２に基本構成を示す逐次転写方式の装置についても、上記と同様な評価を行ったところ、全く同様な結果を示した。
【０１０２】
【発明の効果】
本発明により、小粒径化した場合でも弱帯電性のトナーの発生が少なく、かつ帯電過多となるトナーの発生が少なく、安定した帯電性能を有する静電荷潜像現像トナーを提供することが出来る。
【０１０３】
更に本発明により、キャリア表面への小粒径トナーの付着を抑制し、安定した帯電性能を有する静電荷潜像現像トナーを提供することが出来る。
【０１０４】
更に本発明により、大粒径トナーによる解像度の低下を抑制し、安定した解像度が得られる静電荷潜像現像剤を提供することが出来る。
【０１０５】
更に本発明により、耐久性に優れ、長期に渡って使用してもカブリの発生、転写不良のない、静電荷潜像現像トナーを提供することが出来る。
【０１０６】
更に本発明の他の効果は、上記トナーを好適に使用することのできる画像形成方法を提供することが出来る。
【図面の簡単な説明】
【図１】本発明に用いられる非接触現像方式の一例を示す現像部の概略図である。
【図２】本発明に用いられる逐次転写方式の一例を示す感光体と現像器及び転写ドラムの断面図である。
【図３】本発明に用いられる一括転写方式の一例を示す感光体と現像器の断面図である。
【図４】本発明に用いられるローラ定着方法の概略構成例を示す図である。
【符号の説明】
１ 感光体
２ 現像剤担持体
１２ 現像ユニット
１４ 感光体ドラム
１８ 転写電極
２１ 定着器の上ローラ（加熱部材）
２５ 定着器の下ローラ（加圧部材）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner for developing an electrostatic charge image, a developer, and an image forming method used for a copying machine, a printer, and the like.
[0002]
[Prior art]
In recent years, the electrophotographic development method has been used in various fields. For example, not only copying machines but also printers as computer output terminals, color copying machines, color printers, and the like have come to be used extensively. As use in these wide ranges proceeds, the demand for image quality is increasing. In response to this trend, various requirements have been made on the toner itself, such as a toner having a small particle size and good charging performance.
[0003]
There are various proposals for improving the image quality by reducing the particle size of the toner, and other disclosures of image quality improvement measures are enumerated. However, since the toner having a small particle size has a relatively large surface area because the toner itself is small, the stirring effect per unit surface area is reduced, and there is a problem that the frictional charging property is lowered. As a result, a weakly charged toner is generated, and there is a problem that fog or the like is generated on an image in a long-term use, or a problem that the toner itself is scattered from the developing device. On the other hand, if the volume is sufficiently stirred, the volume is small relative to the surface area, so that an excessively charged toner is generated, which also causes a decrease in density.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide an electrostatic latent image developing toner having a stable charging performance with less generation of weakly charged toner even when the particle size is reduced, and generation of excessively charged toner. It is in.
[0005]
It is another object of the present invention to provide an electrostatic latent image developing toner that suppresses adhesion of a small particle size toner to the carrier surface and has stable charging performance.
[0006]
It is another object of the present invention to provide an electrostatic latent image developer capable of suppressing a decrease in resolution due to a large particle size toner and obtaining a stable resolution.
[0007]
It is another object of the present invention to provide an electrostatic latent image developing toner which is excellent in durability and does not cause fogging or transfer failure even when used for a long period of time.
[0008]
Still another object of the present invention is to provide an image forming method in which the toner can be preferably used.
[0009]
[Means for Solving the Problems]
The object of the present invention is achieved by adopting one of the following configurations.
[0010]
(1)For electrostatic image development with polymer particles associatedIn the toner,The toner has a volume average particle size calculated using a laser diffraction particle size distribution measuring device of 3 to 7 μm, and50% by volume particle size D₅₀And 20% by volume particle size D₂₀Ratio (D₅₀/ D₂₀) Is 1.8 or less, and the particle diameter D is 80% by volume.₈₀And 50% by volume particle size D₅₀Ratio (D₈₀/ D₅₀) Is 1.8 or less, an electrostatic charge image developing toner.
[0011]
(2)For electrostatic image development with polymer particles associatedIn an electrostatic charge image developer comprising a toner and a carrier,The volume average particle size calculated using a laser diffraction particle size distribution analyzer is 3 to 7 μm, and50% by volume particle size D₅₀And 20% by volume particle size D₂₀Ratio (D₅₀/ D₂₀) Is 1.8 or less, and the particle diameter D is 80% by volume.₈₀And 50% by volume particle size D₅₀Ratio (D₈₀/ D₅₀) Is 1.8 or less, an electrostatic charge image developer.
[0012]
(3) At least the latent image formed on the electrostatic latent image carrierFor electrostatic image development with polymer particles associatedIn an image forming method of developing with a toner and visualizing the toner,The volume average particle size calculated using a laser diffraction particle size distribution analyzer is 3 to 7 μm, and50% by volume particle size D₅₀And 20% by volume particle size D₂₀Ratio (D₅₀/ D₂₀) Is 1.8 or less, and the particle diameter D is 80% by volume.₈₀And 50% by volume particle size D₅₀Ratio (D₈₀/ D₅₀) Is 1.8 or less.
[0013]
(4) A recording material carrying a toner image is passed between a moving fixing member and a pressure member moving in pressure contact with the fixing member, and the toner image is passed through the fixing member by a fixedly arranged heating member. In an image forming method for fixing toner on a recording material, the tonerIs a toner in which polymer particles are associated, and the volume average particle size calculated using a laser diffraction particle size distribution analyzer is 3 to 7 μm, and50% by volume particle size D₅₀And 20% by volume particle size D₂₀Ratio (D₅₀/ D₂₀) Is 1.8 or less, and the particle diameter D is 80% by volume.₈₀And 50% by volume particle size D₅₀Ratio (D₈₀/ D₅₀) Is 1.8 or less.
[0014]
As a result of intensive studies, the present inventors have found that the object of the present invention can be achieved by the above-described configuration. The volume average particle diameter measuring apparatus is a laser diffraction particle size distribution measuring apparatus SALD-1100 ( Shimadzu Corporation) was used. It is considered that these particle size ratios are preferably close to 1.0, but the effects of the present invention can be obtained within the above range.
[0015]
As a measurement method, about 5 to 20 mg of a measurement sample is added to about 20 ml of a dispersion medium in which a surfactant is dissolved in water by CMC or more, and dispersion is performed with an ultrasonic disperser for about 30 to 60 seconds. The dispersion sample is diluted to the concentration in the measurable region and measured.
[0016]
The particle size measurement range is set to 0.1 μm to 45 μm, and the volume of toner particles is determined for each channel. The channels are 45-31 μm, 31-22 μm, 22-16 μm, 16-11 μm, 11-7.5 μm, 7.5-5.3 μm, 5.3-3.7 μm, 3.7-2.6 μm, 2 .6 to 1.8 μm, 1.8 to 1.3 μm, 1.3 to 0.88 μm, 0.88 to 0.60 μm, 0.60 to 0.43 μm, 0.43 to 0.30 μm, 0.30 17 channels of .about.0.17 .mu.m, 0.17 to 0.10 .mu.m and 0.10 to 0 .mu.m are used. Using the median value of each channel as a representative diameter, the volume-based particle diameter is calculated from the volume fraction of toner particles in each channel.
[0017]
(1) Toner configuration and manufacturing method
The toner of the present invention preferably contains at least a resin and a colorant, and may contain a release agent, a charge control agent, or the like, which is a fixing property improving agent, if necessary. Furthermore, it may be the one obtained by adding an external additive composed of inorganic fine particles or organic fine particles to colored particles composed of a so-called resin and a colorant.
[0018]
The BET specific surface area of the toner is measured by a one-point method of nitrogen adsorption method, and a specific measuring device includes Flowsorb 2300 (Shimadzu Corporation). A desirable BET specific surface area in the present invention is 5 to 100 m.²/ G, more preferably 7 to 100 m²/ G.
[0019]
The toner of the present inventionInevitablyA monomer is emulsion-polymerized in a liquid to which an emulsified liquid of an essential additive is added to produce fine polymer particles, and thereafter, an organic solvent, an aggregating agent and the like are added and associated with each other. be able to.
[0020]
The method for producing the toner of the present invention is not particularly limited as described above, but is preferably disclosed in Japanese Patent Application Laid-Open No. 5-265252, Japanese Patent Application No. 5-116672, and Japanese Patent Application No. 6-223953. The method shown is used. That is, a method of associating a plurality of fine particles composed of a resin, a colorant, etc., in particular, after dispersing them in water using an emulsifier, infinite dissolution in a flocculant and water at a concentration higher than the critical aggregation concentration Treat with organic solvent. Furthermore, the toner of the present invention can be prepared by heat-sealing at or above the glass transition temperature of the formed polymer itself.
[0021]
Specific examples of monomers used for the resin include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, p- styrene or styrene derivatives such as n-decylstyrene, pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylate -Octyl, 2-ethylhexyl methacrylate, stearyl methacrylate, Methacrylic acid ester derivatives such as lauryl tacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, acrylic acid ester derivatives such as phenyl acrylate, olefins such as ethylene, propylene / isobutylene, vinyl chloride, vinylidene chloride, odor Halogenated vinyls such as vinyl fluoride, vinyl fluoride, vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate, vinyl benzoate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as vinyl, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. There are acrylic acid or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, acrylamide and the like. These vinyl monomers can be used alone or in combination.
[0022]
Further, it is more preferable to use a combination of monomers having an ionic dissociation group as monomers constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.
[0023]
Furthermore, polyfunctionality such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.
[0024]
These monomers can be made into a resin using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method or the solution polymerization method. As this oil-soluble polymerization initiator, azoisobutyronitrile, lauryl peroxide, benzoyl peroxide, or the like can be used. Moreover, when using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide, and the like.
[0025]
The flocculant used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, an alkali metal salt such as sodium, potassium or lithium, as a divalent metal, for example, an alkaline earth metal salt such as calcium or magnesium, or a divalent metal such as manganese or copper. Salts, trivalent metal salts such as iron and aluminum, etc., and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, inexpensive zinc, copper sulfate, magnesium sulfate, manganese sulfate, etc. Can be mentioned. These may be used in combination.
[0026]
These flocculants are preferably added in an amount equal to or higher than the critical aggregation concentration. The critical flocculation concentration is an index relating to the stability of the aqueous dispersion, and indicates a concentration at which flocculation occurs when a flocculant is added. This critical aggregation concentration varies greatly depending on the emulsified components and the dispersant itself. For example, it is described in Seizo Okamura et al., “Polymer Chemistry 17, 601 (1960) Journal of Polymer Society” and the like, and a detailed critical aggregation concentration can be obtained. As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is defined as the critical aggregation concentration. You can ask for it.
[0027]
The addition amount of the flocculant of the present invention may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.
[0028]
The infinitely soluble solvent refers to a colored polymer dispersion, that is, a solvent that is infinitely soluble in water. In the present invention, a solvent that does not dissolve the formed resin is selected. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol, and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. In particular, ethanol, propanol, and isopropyl alcohol are preferable.
[0029]
The addition amount of the infinitely soluble solvent is preferably 1 to 300% by volume with respect to the polymer-containing dispersion added with the flocculant.
[0030]
Various methods can be used as the polymerization method for forming the resin used for forming the toner of the present invention, and the emulsion polymerization method described above is preferable as a particularly preferable method.
[0031]
As the colorant used in the toner of the present invention, carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used. Examples of the carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used. As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 etc. can be used, and a mixture thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 93, 94, 138, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.
[0032]
As a method for adding the colorant, the polymer itself is adjusted by an emulsion polymerization method, and then added at the stage of agglomeration by adding an aggregating agent, and the polymer is polymerized at the stage of polymerizing the monomer. A method of adding a colorant, polymerizing, and coloring can be used. In addition, when adding a coloring agent in the step which synthesize | combines a polymer, it is preferable to process and use the surface by a coupling agent etc. so that radical polymerization property may not be inhibited.
[0033]
Further, a low molecular weight polypropylene (number average molecular weight = 1500 to 9000), a low molecular weight polyethylene, or the like as a fixing property improving agent may be added. An azo metal complex, a quaternary ammonium salt, or the like may be used as a charge control agent.
[0034]
Further, from the viewpoint of imparting fluidity, inorganic fine particles and organic fine particles may be added to the colored particles obtained by polymerization. In this case, the use of inorganic fine particles is preferable, the use of inorganic oxide particles such as silica, titania, and alumina is preferable, and these inorganic fine particles are hydrophobized with a silane coupling agent, a titanium coupling agent, or the like. Is preferred.
[0035]
The toner of the present invention can be produced by associating a plurality of the aforementioned polymers. In this case, the metal salt as a coagulant is critically aggregated while stirring the dispersion of polymer particles. It can be obtained by adding an amount higher than the concentration, further adding a solvent (for example, isopropyl alcohol) that is infinitely soluble in water, and further heat-treating the polymer at or above the glass transition temperature.
[0036]
The toner of the present invention may be used, for example, as a one-component magnetic toner containing a magnetic material, used as a two-component developer mixed with a so-called carrier, or a non-magnetic toner alone. However, in the present invention, it is preferably used as a two-component developer used by mixing with a carrier.
[0037]
As the carrier constituting the two-component developer, either an uncoated carrier composed only of magnetic material particles such as iron or ferrite, or a resin-coated carrier whose magnetic material particle surface is coated with a resin or the like may be used. The average particle size of the carrier is preferably 30 to 150 μm in terms of volume average particle size. In addition, the resin for coating is not particularly limited, and examples thereof include styrene-acrylic resins.
[0038]
In addition, as an excellent resin, those having a glass transition point of 20 to 90 ° C are preferable, and those having a softening point of 80 to 220 ° C are preferable. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Further, these resins preferably have a molecular weight measured by gel permeation chromatography of 1,000 to 100,000 in terms of number average molecular weight (Mn) and 2000 to 1,000,000 in terms of weight average molecular weight (Mw). Further, the molecular weight distribution is preferably such that Mw / Mn is 1.5 to 100, particularly 1.8 to 70.
[0039]
(2) Configuration of image forming method
The developing system in which the toner of the present invention can be used is not particularly limited. It can be suitably used for a contact development system or a non-contact development system. In particular, the toner of the present invention has a high charge rising property and is useful for a non-contact development method.
[0040]
That is, in the non-contact development method, since the change in the development electric field is large, a slight change in charging acts on the development itself. For this reason, a large fluctuation is caused with respect to a change in the charge amount of the toner. However, since the toner of the present invention has a high charge rising property, there is little change in charge, and a stable charge amount can be secured, so that a stable image can be formed over a long period of time even with a non-contact development method. it can.
[0041]
For contact-type development, the layer thickness of the developer having the toner of the present invention is preferably 0.1 to 8 mm, particularly 0.4 to 5 mm in the development region. The gap between the photosensitive member and the developer carrying member is preferably 0.15 to 7 mm, particularly preferably 0.2 to 4 mm.
[0042]
In the non-contact development method, the developer layer formed on the developer carrying member and the photosensitive member are not in contact with each other, and the developer layer is formed as a thin layer in order to constitute this development method. It is preferable. In this method, a developer layer having a thickness of 20 to 500 μm is formed in the developing region on the surface of the developer carrying member, and the gap between the photosensitive member and the developer carrying member is larger than the developer layer. The thin layer is formed by a magnetic blade using magnetic force, a method of pressing a developer layer regulating rod on the surface of the developer carrying member, or the like. Further, there is a method of regulating the developer layer by bringing a urethane blade, a phosphor bronze plate or the like into contact with the surface of the developer carrying member. The pressing force of the pressing restricting member is preferably 1 to 15 gf / mm. When the pressing force is small, the regulation force is insufficient, and thus the conveyance is likely to be unstable. On the other hand, when the pressing force is large, the stress on the developer is increased, and the durability of the developer is likely to be lowered. A more preferable range is 3 to 10 gf / mm. The gap between the developer carrying member and the photoreceptor surface must be larger than the developer layer. Furthermore, when a developing bias is applied during development, either a method of applying only a DC component or a method of applying an AC bias may be used.
[0043]
The developer carrying member preferably has a diameter of 10 to 40 mm. When the diameter is small, mixing of the developer is insufficient, making it difficult to ensure sufficient mixing to impart sufficient charge to the toner, and when the diameter is large, the centrifugal force on the developer increases. Prone to toner scattering problem.
[0044]
Hereinafter, an example of the non-contact development method will be described with reference to FIG.
[0045]
FIG. 1 is a schematic view of a developing portion of a non-contact developing system that can be suitably used in the image forming method of the present invention, wherein 1 is a photoreceptor, 2 is a developer carrier, and 3 is a toner containing the toner of the present invention. Component developer, 4 is a developer layer regulating member, 5 is a development region, 6 is a developer layer, and 7 is a power source for forming an alternating electric field.
[0046]
The two-component developer containing the toner of the present invention is carried by a magnetic force on the developer carrying member 2 having a magnet 2B therein, and is conveyed to the developing region 5 by the movement of the developing sleeve 2A. During the conveyance, the thickness of the developer layer 6 is regulated by the developer layer regulating member 4 so that the developer layer 6 does not come into contact with the photoreceptor 1 in the development region 5.
[0047]
The minimum gap (Dsd) of the development region 5 is larger than the thickness (preferably 20 to 500 μm) of the developer layer 6 conveyed to that region, for example, about 100 to 1000 μm. The power source 7 for forming the alternating electric field is preferably an alternating current having a frequency of 1 to 10 kHz and a voltage of 1 to 3 kVp-p. The power supply 7 may have a configuration in which direct current is added in series with alternating current as necessary. The DC voltage is preferably 100 to 800V.
[0048]
The image forming method in FIGS. 2 and 3 will be described in detail below.
[0049]
As the developer carrier used in the present invention, as shown in FIG. 1, a developing device incorporating a magnet 2B is used inside the carrier, and the sleeve 2A constituting the developer carrier surface is made of aluminum or the like. Aluminum or stainless steel whose surface is oxidized is used.
[0050]
Hereinafter, an example of the sequential transfer method shown in FIG. 2 will be described.
[0051]
A charging unit 11 is a charging electrode, and a developing unit 12 is composed of a developing unit loaded with yellow, magenta, cyan, and black toners, and is divided into four units corresponding to four color toners. The basic configuration of these developing units is the same as the schematic diagram of the developing unit shown in FIG. Reference numeral 14 denotes a photosensitive drum, 13 denotes a cleaning unit, and 15 denotes a transfer drum carrying a recording material for transferring a monochrome toner image formed on the photosensitive drum. The monochrome color is sequentially applied onto the recording material carried thereon. The toner image is transferred to finally form a desired multicolor image. A transport unit 16 transports a recording material onto which a toner image on the transfer drum is transferred. An adsorption electrode 17 is provided inside the transfer drum 15 and electrostatically attracts the recording material to the drum by corona discharge from the inside. , 18 is a transfer electrode for sequentially transferring the toner image formed on the photosensitive drum 14 to the transfer drum 15, 19 is a release electrode for peeling the recording material electrostatically adsorbed on the transfer drum 15, and 20 is a recording material. It is a removal electrode that removes the charge remaining on the transfer drum after peeling.
[0052]
Electric charges are uniformly formed on the photosensitive drum 14 by the charging electrode 11, and then imagewise exposure (means not shown) is performed to form an electrostatic latent image. The electrostatic latent image is developed by a developing device that holds one color toner (for example, black toner) in the developing unit 12, and a one color toner image is formed on the photosensitive drum 14. On the other hand, the recording material transported onto the transfer drum 15 by the transport unit 16 is electrostatically attracted onto the transfer drum by the suction electrode 17 and transported to the transfer unit.
[0053]
The toner image formed on the photosensitive drum 14 is transferred to the conveyed recording material by the transfer electrode 18. The toner remains on the photosensitive drum 14 after transferring the toner image, and the residual toner is cleaned by the cleaning unit 13 and used in the next process. When a multicolor image is formed, toner images of other colors are formed by development according to a similar process, and transferred to a recording material on the transfer drum 15 one by one. Finally, a desired toner image is formed on the recording material adsorbed on the transfer drum 15. The recording material carrying the desired toner image is peeled off by the peeling electrode 19 (the peeling electrode 19 is in an inactive state until this stage) and conveyed to the fixing unit to obtain a final fixed multicolor toner image. It is done. On the other hand, the transfer drum 15 removes the remaining charges by the removal electrode 20 and is used for the next process. The movement of the recording material in FIGS. 2 and 3 is indicated by a large arrow.
[0054]
Next, the batch transfer method will be described with reference to FIG.
[0055]
Since each part of the apparatus is the same as the example of FIG. Reference numeral 10 denotes a transport unit that transfers the toner image while transporting the transported recording material. Electric charges are uniformly formed on the photosensitive drum 14 by charging electrodes, and then an electrostatic latent image is formed by latent image forming means (means not shown). This electrostatic latent image is developed by a developing unit that holds toner of one color (for example, black toner) in the developing unit 12, and a toner image of one color is formed on the photosensitive drum. In this example, the toner image is not transferred, and a charge is uniformly formed again on the photosensitive drum having the toner image as it is, and an electrostatic latent image is further formed. The toner image is developed by a developing device having toner of a color different from the above, and toner images of other colors are superimposed on the previous toner image. During this time, the cleaning unit 13, the transfer electrode 18, and the transport unit 10 are retracted from the photoconductive drum 14 so that the toner image on the photoconductive drum 14 is not disturbed.
[0056]
After the desired image formation is completed and a multicolor toner image is formed, the toner image on the photosensitive drum is conveyed by the conveyance unit 16 and then transferred to the recording material conveyed by the conveyance unit 10 to the transfer electrode. 18 is transferred. The recording material carrying the transferred toner image is conveyed to a fixing unit and fixed, and a final multicolor toner image is formed on the recording material. Since the untransferred toner remains on the photosensitive drum 14 after the toner image is transferred, it is cleaned by the cleaning unit 13 and used in the next process.
[0057]
The toner image formed on the photosensitive drum by the various methods described above is transferred to a recording material such as paper by a transfer process. The transfer method is not particularly limited, and various methods such as a so-called corona transfer method and a roller transfer method can be employed.
[0058]
For the fixing process used in the present invention, a roller fixing system will be described with reference to FIG. 4 as an example.
[0059]
The fixing device in FIG. 4 includes a heating source 24 (heating) inside a metal cylinder 23 made of iron, aluminum, or the like whose surface 22 is coated with, for example, tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymers. And a lower roller 25 (pressure member) made of silicone rubber or the like. Specifically, a linear heater is used as the heating source 24, and the surface temperature of the upper roller 21 is heated to about 110 to 220 ° C. The recording material 26 carrying the toner image 27 of the present invention is passed between the upper roller 21 and the lower roller 25 that are in pressure contact, and the toner image 27 is heat-melted and fixed on the recording material.
[0060]
In the heat roller fixing method, a part of the melted toner is fused to the upper roller 21, and after one rotation, an offset phenomenon occurs in which the toner fused to the upper roller 21 is fixed to another part of the recording material. In the case of dripping, the toner fused to the upper roller 21 does not leave the recording material and winds around the upper roller 21 together with the recording material, so that a so-called wrapping phenomenon occurs and the surface of the recording material becomes dirty. However, when the toner of the present invention is used, the drawbacks can be remarkably improved.
[0061]
In the fixing unit, pressure is applied between the upper roller 21 and the lower roller 25 to deform the lower roller 25 to form a so-called nip. The nip width is preferably 1 to 10 mm, more preferably 1.5 to 7 mm. The fixing linear velocity is preferably 40 to 400 mm / sec. When the nip width is narrow, heat cannot be uniformly applied to the toner, and uneven fixing tends to occur. On the other hand, when the nip width is wide, the melting of the toner is promoted and an offset phenomenon is likely to occur.
[0062]
In the roller fixing method used in the present invention, a silicone oil coating film may be formed on the surface 22 of the upper roller 21. As an example, the formation method of the silicone oil coating film on the surface 22 of the upper roller 21 is performed as follows.
[0063]
That is, the impregnation roller 28 is pressed against the surface 22 of the upper roller 21 in the longitudinal direction and is rotated in the direction of the arrow. The impregnation roller 28 is impregnated with silicone oil in advance, and at the time of fixing, silicone oil is supplied from the impregnation roller 28 to the surface of the upper roller 21 little by little as the upper roller 21 rotates. As a result, a silicone oil coating film is formed on the surface 22 of the upper roller 21.
[0064]
As for the fixing method, in addition to the roller fixing described above, those using a web as a fixing member are preferably used in the present invention.
[0065]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.
[0066]
Colored particle production example 1
[Production of colorant dispersion]
Carbon black (Regal 330R: manufactured by Cabot Corporation) treated with an aluminum coupling agent (Plenact Al-M: Ajinomoto Co.) was added to 10.67 g of a solution prepared by dissolving 4.92 g of sodium dodecyl sulfate in 120 ml of pure water. Then, an aqueous dispersion of carbon black was prepared by applying ultrasonic waves while stirring.
[0067]
[Production of colored polymer particles]
A 2 l separable flask equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction tube was mixed with 43 g of the low molecular weight polypropylene emulsified dispersion in the carbon black dispersion, and further 98.1 g of styrene monomer, n- After adding 18.4 g of butyl acrylate monomer, 6.1 g of methacrylic acid monomer, 3.3 g of t-dodecyl mercaptan and 850 ml of degassed pure water, the temperature was raised to 70 ° C. while stirring under a nitrogen stream. Then, 200 ml of pure water in which 4.1 g of potassium persulfate was dissolved was added and reacted at 70 ° C. for 6 hours. The resulting carbon black-containing colored particle dispersion is referred to as “Dispersion 1”. In addition, the primary particle diameter (light scattering electrophoresis particle size measuring device ELS-800: manufactured by Otsuka Electronics Co., Ltd.) and molecular weight distribution (styrene conversion molecular weight) of this product were measured.
[0068]
[Production of colored particles]
Add 5N NaOH aqueous solution to 250ml of the above "Dispersion 1", adjust the pH to 9, pour into a 500ml separable flask equipped with a stirrer, condenser, and temperature sensor, and stir at 250rpm at room temperature. . To this, an aqueous solution in which 15.4 g of potassium chloride is dissolved in 65 ml of distilled water is added, and further 2 g of polyoxyethylene octylphenyl ether (the average degree of polymerization of ethylene oxide is 10) is added to 40 ml of isopropyl alcohol and 20 ml of distilled water. Dissolved aqueous solution was added.
[0069]
Then, it heated up to 85 degreeC and made it react for 6 hours. After completion of the reaction, the reaction solution is filtered, suspended and dispersed in distilled water, and the pH is adjusted to 13 using 5N NaOH aqueous solution. Thereafter, washing by filtration was repeated and dried to obtain colored particles.
[0070]
The colored particles were classified using a pressure loss type classifier 132MP (manufactured by Yaskawa Corp.) to obtain the colored particles of the present invention. This is referred to as “colored particles 1”.
[0071]
In addition, the average particle diameter (Laser diffraction type particle size distribution measuring device SALD-1100: manufactured by Shimadzu Corporation) and the BET surface area (BET surface area measuring device Flowsorb II 2300: manufactured by Shimadzu Corporation) were measured. .
[0072]
Colored particle production example 2
In Colored Particle Production Example 1, C.I. I. The colored particles of the present invention were obtained in the same manner except that CI Pigment Blue 15: 3 was used. The dispersion obtained here is referred to as “dispersion 2”, and the colored particles are referred to as “colored particles 2”.
[0073]
Colored particle production example 3
In Colored Particle Production Example 1, C.I. I. The colored particles of the present invention were obtained in the same manner except that CI Pigment Red 122 was used. The dispersion obtained here is referred to as “dispersion 3”, and the colored particles are referred to as “colored particles 3”.
[0074]
Colored particle production example 4
In Colored Particle Production Example 1, C.I. I. The colored particles of the present invention were obtained in the same manner except that CI Pigment Yellow 17 was used. The dispersion obtained here is referred to as “dispersion 4”, and the colored particles are referred to as “colored particles 4”.
[0075]
Colored particle production example 5
The colored particles of the present invention were obtained in the same manner as in Colored Particle Production Example 1, except that “Dispersion 1” was used and a pressure loss classifier DS-2 (manufactured by Nippon Pneumatic Industry Co., Ltd.) was used in combination. This is designated as “colored particles 5”.
[0076]
Colored particle production example 6
In Colored Particle Production Example 1, “Dispersion 1” was used, 17 g of potassium chloride was added, and a pressure drop classifier DS-2 (manufactured by Nippon Pneumatic Industry Co., Ltd.) was used. Colored particles were obtained. This is designated as “colored particles 6”.
[0077]
Colored particle production example 7
Colored particles of the present invention were obtained in the same manner as in Colored Particle Production Example 2 except that “Dispersion 2” was used and 13.8 g of potassium chloride was added. This is designated as “colored particles 7”.
[0078]
Example of colored particle production8
The colored particles of the present invention were obtained in the same manner as in Colored Particle Production Example 3 except that “Dispersion 3” was used, the amount of isopropyl alcohol added was 54 ml, and potassium chloride was 14.5 g. This is designated as “colored particles 8”.
[0079]
Colored particle production example 9
In the same manner as in Colored Particle Production Example 4, except that “Dispersion 4” was used and 2.5 g of polyoxyethylene octylphenyl ether was used, colored particles of the present invention were obtained. This is designated as “colored particles 9”.
[0080]
Comparative colored particle production example 1
Using 100 parts of a styrene-n-butyl acrylate copolymer (copolymer ratio = 85: 15, weight average molecular weight = 63000), adding 10 parts of carbon black and 5 parts of low molecular weight polypropylene (number average molecular weight = 3200). Kneading and pulverization classification were performed to obtain colored particles for comparison. This is designated as “Comparison Colored Particle 1”.
[0081]
Colored particle production example 2 for comparison
In Comparative Colored Particle Production Example 1, C.I. I. Comparative colored particles were obtained in the same manner except that CI Pigment Blue 15: 3 was used. This is designated as “Comparison Colored Particle 2”.
[0082]
Comparative Colored Particle Production Example 3
In Comparative Colored Particle Production Example 1, C.I. I. Comparative colored particles were obtained in the same manner except that CI Pigment Red 122 was used. This is designated as “Comparison Colored Particle 3”.
[0083]
Comparative Colored Particle Production Example 4
In Comparative Colored Particle Production Example 1, C.I. I. Comparative colored particles were obtained in the same manner except that CI Pigment Yellow 17 was used. This is designated as “comparative colored particles 4”.
[0084]
Example of toner production
1% by weight of hydrophobic silica (primary average particle diameter = 12 nm) is added to the “colored particles 1” to “colored particles 9” and “comparative colored particles 1” to “comparative colored particles 4”, A toner was obtained. These are “toner 1” to “toner 9” and “comparative toner 1” to “comparative toner 4”.
[0085]
“Dispersion 1” to “Dispersion 4”, “Colored particles 1” to “Colored particles 9”, “Colored particles 1 for comparison” to “Colored particles 4 for comparison”, “Toner 1” to “Toner 9” Tables 1 and 2 below show various physical properties of “Comparative Toner 1” to “Comparative Toner 4”. As a result of the measurement, there was almost no difference between the physical properties of the toner and the colored particles, so the display shows the physical properties of the toner.
[0086]
[Table 1]

[0087]
[Table 2]

[0088]
Evaluation
The above toner was mixed with a ferrite carrier having a volume average particle diameter of 50 μm coated with styrene-acrylic resin, and a developer having a toner concentration of 7% by weight was prepared for use.
[0089]
Note that the developers corresponding to the above “toner 1” to “toner 9” and “comparative toner 1” to “comparative toner 4” are “developer 1” to “developer 9” and “comparative developer 1”. To “Comparative Developer 4”.
[0090]
(Contact development method)
Evaluation was performed using a Konica U-BIX 3135 copier manufactured by Konica. The developer layer thickness is 1.5 mm, and the gap (Dsd) between the photosensitive member and the developer carrying member (developing sleeve) is 0.5 mm.
[0091]
The evaluation condition is that after 10,000 sheets are continuously printed in a low-temperature and low-humidity (10 ° C, 10% RH) environment, the printing is performed up to 60,000 sheets by repeating the printing after leaving for 24 hours. Concentration was measured. The results are shown in Table 3 below.
[0092]
The fog density is a relative density where the paper density is 0, and is measured with a Macbeth densitometer (RD-918). For evaluation, “Developer 1”, “Developer 4”, “Developer 5” and “Comparative Developer 1” were used.
[0093]
[Table 3]

[0094]
“Developer 1”, “Developer 4” and “Developer 5” in the present invention show almost no increase in fog even when printing up to 60,000 sheets, whereas “Comparative developer 1” has an initial value. Is good, but it increases gradually.
[0095]
(Non-contact development method)
In the evaluation, a color copying machine Konica 9028 manufactured by Konica, which is a non-contact development type and batch transfer type, was used after being modified. The conditions are as shown below. As the photoconductor, a laminated organic photoconductor was used.
[0096]
Photoconductor surface potential = -550V
DC bias = -250V
AC bias = Vp-p: -50 to -450V
Alternating electric field frequency = 1800Hz
Dsd = 300 μm
Press restriction force = 10 gf / mm
Pressure regulating bar = SUS416 (made of magnetic stainless steel) / diameter 3mm
Developer layer thickness = 150 μm
Development sleeve = 20 mm
Note that the developer is a combination of “Developer 1” to “Developer 4”, “Developer 6” to “Developer 9”, and “Comparative developer 1” to “Comparative developer 4”. Used as an agent.
[0097]
The evaluation method was a full color image with a pixel rate of 75%, and printing was performed in a high temperature and high humidity environment (33 ° C., 80% RH). Printing was performed continuously for 1000 sheets, and then up to 10,000 sheets in a system where the printing was continued for 24 hours, and the number of occurrences of transfer unevenness was recorded.
[0098]
The evaluation results are shown in the following table.
[0099]
[Table 4]

[0100]
The “Developer 1” to “Developer 4” and “Developer 6” to “Developer 9” in the present invention have no problem, whereas “Comparative developer 1 outside the present invention”. It can be seen that the combination of “Comparative Developer 4” does not have sufficient characteristics.
[0101]
In addition, when the same evaluation as described above was performed on the sequential transfer type apparatus having the basic configuration shown in FIG. 2, the same result was obtained.
[0102]
【The invention's effect】
According to the present invention, it is possible to provide an electrostatic latent image developing toner having a stable charging performance with less generation of weakly charged toner even when the particle size is reduced, and generation of excessively charged toner. .
[0103]
Further, according to the present invention, it is possible to provide an electrostatic latent image developing toner that suppresses the adhesion of a small particle size toner to the carrier surface and has a stable charging performance.
[0104]
Furthermore, according to the present invention, it is possible to provide an electrostatic latent image developer capable of suppressing a decrease in resolution due to a large particle size toner and obtaining a stable resolution.
[0105]
Furthermore, according to the present invention, it is possible to provide an electrostatic latent image developing toner which has excellent durability and does not cause fogging or transfer failure even when used for a long period of time.
[0106]
Furthermore, another effect of the present invention can provide an image forming method in which the above toner can be preferably used.
[Brief description of the drawings]
FIG. 1 is a schematic view of a developing unit showing an example of a non-contact developing method used in the present invention.
FIG. 2 is a cross-sectional view of a photoreceptor, a developing device, and a transfer drum showing an example of a sequential transfer method used in the present invention.
FIG. 3 is a cross-sectional view of a photoconductor and a developing device showing an example of a batch transfer method used in the present invention.
FIG. 4 is a diagram showing a schematic configuration example of a roller fixing method used in the present invention.
[Explanation of symbols]
1 Photoconductor
2 Developer carrier
12 Development unit
14 Photosensitive drum
18 Transfer electrode
21 Upper roller (heating member) of fixing unit
25 Lower roller (pressure member) of the fixing unit

Claims (4)

In the toner for developing an electrostatic charge image in which polymer particles are associated , the toner has a volume average particle size calculated using a laser diffraction particle size distribution measuring device of 3 to 7 μm, and 50% by volume. The ratio (D ₅₀ / D ₂₀ ) between the particle size D ₅₀ and the 20% by volume particle size D ₂₀ is 1.8 or less, and the 80% by volume particle size D ₈₀ and the 50% by volume particle size D ₅₀ A toner for developing electrostatic images, wherein the ratio (D ₈₀ / D ₅₀ ) is 1.8 or less. In an electrostatic charge image developer comprising an electrostatic charge image developing toner and a carrier in which polymer particles are associated, the volume average particle size calculated using a laser diffraction particle size distribution measuring device of the toner is 3 to 3. 7 μm, and the ratio (D ₅₀ / D ₂₀ ) of 50 volume% particle diameter D ₅₀ to 20 volume% particle diameter D ₂₀ is 1.8 or less, and 80 volume% particle diameter D ₈₀ An electrostatic charge image developer, wherein a ratio (D ₈₀ / D ₅₀ ) with a particle size D ₅₀ of 50 volume% is 1.8 or less. In an image forming method in which at least a latent image formed on an electrostatic latent image bearing member is developed with a toner for developing an electrostatic image in which polymer particles are associated , and visualized, the laser diffraction particle size of the toner The volume average particle diameter calculated using a distribution measuring device is 3 to 7 μm, and the ratio (D ₅₀ / D ₂₀ ) of 50 volume% particle diameter D ₅₀ and 20 volume% particle diameter D ₂₀ is An image forming method, wherein the ratio (D ₈₀ / D ₅₀ ) of the particle size D _{80 of 80} % by volume to the particle size D _{50 of 50} % by volume is 1.8 or less. A recording material carrying a toner image is passed between a moving fixing member and a pressure member moving in pressure contact with the fixing member, and the toner image is recorded via the fixing member by a heating member fixedly arranged. In the image forming method to be fixed on the toner, the toner is a toner in which polymer particles are associated, the volume average particle size calculated using a laser diffraction particle size distribution measuring device is 3 to 7 μm, and 50 volumes. % particle size D ₅₀ and the ratio of the 20 vol% particle size D ₂₀ (D ₅₀ / D ₂₀₎ is 1.8 or less, 80% by volume of the particle diameter D ₈₀ of 50 volume% particle size D ₅₀ (D ₈₀ / D ₅₀ ) is 1.8 or less.

Images