JP2004294534A - Electrophotographic nonmagnetic toner and developing method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic nonmagnetic toner which ensures high transfer efficiency and no inadequacy of image density even in the case of low toner consumption (small toner layer thickness, small toner coating weight), is free of the problem of fusion bonding even in continuous printing on many sheets, has good developing performance and high endurance, and ensures low consumption. <P>SOLUTION: The electrophotographic nonmagnetic toner contains at least a binder resin and a colorant, and when a coating weight X (mg/cm<SP>2</SP>) of the toner on a transfer medium is in the range of 0.4-0.8, image density Y represented by the expression (1); Y=αX<SP>2</SP>+βX+0.08 is 0.9≤Y≤1.9, wherein α is -0.4 to -1.8 and βis 2.4 to 3.2. A nonmagnetic one-component developing method using the toner is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４２】
【表２】

【００４３】
【表３】

【００４４】
＜評価結果＞
表２および表３から明らかなように、実施例１〜６の本発明のトナーでは、初期から６０００枚後の画像濃度は１．１０〜１．９０であり、カブリは０．７０以下で実用上問題ない範囲で複写でき、且つ、トナー消費量は１１５ｇ以下／６０００枚であり、平均転写効率７５％以上、画像は鮮やかで実用上問題ないことが確認された。これに対し比較例１のトナーは、βが小さく、画像濃度が小さかった。
一方、比較例２のトナーは、αが小さく、βが大きく、トナー消費量が多く、転写効率が小さく、カブリもやや多かった。比較例３のトナーは、αが大きく、画像濃度が過剰で画像の鮮やかさが劣っていた。比較例４のトナーは、αが大きく、βが小さく、トナー消費量が多く、転写効率が小さく、画像濃度がやや小さかった。
【００４５】
【発明の効果】
以上説明したように、本発明は、低トナー消費量（低トナー層厚、低トナー付着量）であっても、高転写効率であり、画像濃度の不足が起こらず、融着等の問題が多数枚連続プリント時においても発生せず、現像性が良好であり、高耐久、低消費量の電子写真用非磁性トナー及びそれを用いた現像方法を提供することことができるという画期的効果を奏する。
【図面の簡単な説明】
【図１】本発明の現像方法で用いられる装置の一例の概略説明図。
【図２】本発明の実施例１の式（１）関係を示すグラフ
【図３】本発明の実施例２の式（１）関係を示すグラフ
【図４】比較例２の式（１）関係を示すグラフ
【図５】比較例３の式（１）関係を示すグラフ
【符号の説明】
１ 感光体ドラム
２ ホッパー
３ 非磁性一成分現像剤
４ 層規制部材
５ 現像ローラー
６ 攪拌機
７ 電源[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-magnetic toner for electrophotography applied to an image forming apparatus such as a printer or a facsimile using electrophotography and a developing method using the same. In particular, it relates to a full-color toner and a developing method using the same. The invention also relates to a non-magnetic one-component jumping development method.
[0002]
[Prior art]
A dry developer applied to the development of an image forming apparatus using electrophotography is a two-component developer in which a toner and a carrier made of ferrite powder, iron powder, glass beads, etc. are mixed, and a magnetic powder is used for the toner itself. And a non-magnetic one-component developer. The toner used in these developers contains a binder resin and a colorant as main components. In addition, a wax for improving low-temperature fixability to a recording sheet and a releasing property of a fixing member, and a polar ( A charge control agent or the like for giving positive charge or negative charge) is added. The toner is manufactured into a powder through a process such as melt-kneading, pulverization, and classification after these materials are mixed in a predetermined formulation, and finally, for control of fluidity, chargeability, cleaning property, storage property, and the like. Is subjected to a surface treatment with an external additive such as silica, titanium oxide, alumina and various kinds of resin fine particles, and finally used as a developer.
[0003]
2. Description of the Related Art In recent years, in the field of application of electrophotographic technology, there has been an increasing demand for reducing the size of machines, as well as improving and upgrading image quality, and for reducing waste in order to protect the natural environment. As for the reduction of waste, there is a demand for a reduction in toner consumption, that is, a reduction in the amount of toner attached to a transfer medium and an improvement in transfer efficiency.
The non-magnetic one-component developing method is suitable for reducing the size of the machine and reducing waste.
[0004]
On the other hand, full color copying machines and printers have appeared on the market in response to demands for higher image quality, and it has been expected that the penetration rate will increase dramatically. However, the current situation is far lower than expected. A full-color machine uses four colors of toner, and a tandem system requires four photoreceptor units, which inevitably requires higher running costs than a monochrome machine, and the price of color toner is high, which greatly hinders its spread. It has become. Therefore, in the color toner, it is important to reduce the amount of the toner adhered to the transfer medium and to reduce the running cost by improving the transfer efficiency, as well as lowering the toner itself.
[0005]
Considering the above situation, when trying to achieve the maintenance of full-color image quality, downsizing of machines, reduction of consumables costs, reduction of machine costs, etc., a non-magnetic one-component jumping development method with a 4-pass system is This is considered to be one suitable method. However, in jumping development, the flying property of toner has a great effect on image quality because of non-contact development. Poor flight performance results in insufficient ID and lower image quality.
In particular, non-magnetic one-component developing devices have high stress on toner, and the toner may be finely powdered or may be fused to a developing roll or a layer thickness regulating member. There are many cases where is deteriorated.
[0006]
[Patent Document 1]
JP-A-11-84719
[Patent Document 2]
JP 2001-22118A
[Patent Document 3]
JP-A-60-87345
[Patent Document 4]
JP-A-8-305076
[Patent Document 5]
JP-A-63-13055
[0007]
[Problems to be solved by the invention]
In the non-magnetic one-component developing method, in order to reduce the amount of toner consumption, in an attempt to reduce the amount of toner attached to the transfer medium, attempts have been made to reduce the thickness of the toner layer on the developing roller. A decrease in fusion resistance was inevitable. It has also been important to improve transfer efficiency.
[0008]
Therefore, the present invention has a high transfer efficiency even when the toner consumption is low (low toner layer thickness and low toner adhesion amount), does not cause a shortage of image density, and causes a problem such as fusion when printing many sheets continuously. An object of the present invention is to provide a non-magnetic toner for electrophotography which does not occur even in the above-mentioned conditions, has good developing property, and has high durability and low consumption.
[0009]
[Means for Solving the Problems]
The non-magnetic toner for electrophotography of the present invention contains at least a binder resin and a colorant, and has a toner adhesion amount X (mg / cm²) Is in the range of 0.4 to 0.8, the image density Y is 0.9 ≦ Y ≦ 1.9, α in the following formula (1) is −0.4 to −1.8, and β is This is a non-magnetic toner for electrophotography, which satisfies 2.4 to 3.2 (claim 1).
[Equation 3] Y = αX²+ ΒX + 0.08 (1)
2. The non-magnetic toner according to claim 1, wherein the non-magnetic toner has a dielectric constant of 1.0 to 2.3 and a true specific gravity of 0.90 to 1.15. It is a toner (claim 2).
The non-magnetic toner of the present invention comprises a hydrophobic silica having a volume average particle diameter of 30 to 70 nm, a silicone oil having a viscosity at 25 ° C. of 30 to 3000 CS, and a BET specific surface area of 30 to 100 m.²/ G, wherein at least one of the hydrophobic titanium oxides is used as an external additive, and the total amount of the external additive is 1.0 to 3.0% by weight based on the toner particles. (Embodiment 3). The non-magnetic toner for electrophotography according to any one of claims 1 to 3, wherein the non-magnetic toner of the present invention is used in a non-magnetic one-component jumping development method (claim 4).
The non-magnetic toner of the present invention is a non-magnetic toner for electrophotography according to any one of claims 1 to 4, wherein the non-magnetic toner is for full color use (claim 5).
The developing method of the present invention contains at least a binder resin and a colorant, and has a toner adhesion amount X (mg / cm²) Is in the range of 0.4 to 0.8, the image density Y is 0.9 ≦ Y ≦ 1.9, α in the following formula (1) is −0.4 to −1.8, and β is This is a non-magnetic one-component jumping developing method characterized by using a non-magnetic toner for electrophotography, which specially satisfies 2.4 to 3.2.
[Formula 4] Y = αX²+ ΒX + 0.08 (1)
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the non-magnetic toner for electrophotography and the developing method of the present invention will be described.
The toner of the present invention contains at least a binder resin and a colorant, and optionally contains a charge control agent, a release agent, a fixing property improving agent, and other additives. Further, it is preferable to attach a fluidity improver or the like to the surface of the toner particles.
[0011]
The non-magnetic toner of the present invention contains at least a binder resin and a colorant, and has a toner adhesion amount X (mg / cm²) Is in the range of 0.4 to 0.8, the image density Y is 0.9 ≦ Y ≦ 1.9, α in the following formula (1) is −0.4 to −1.8, and β is It is a non-magnetic toner for electrophotography, which satisfies 2.4 to 3.2.
[Formula 5] Y = αX²+ ΒX + 0.08 (1)
If Y is less than 0.9, the image density is insufficient, and if it exceeds 1.9, there are problems such as deterioration of image quality (color = vividness) and increase in consumption. If α exceeds -0.4, the image density becomes insufficient, and if it is less than -1.8, the change in density with respect to the amount of adhesion becomes too sensitive and the image stability deteriorates. If β is less than 2.4, the image density becomes insufficient, and if it exceeds 3.2, the change in density with respect to the amount of adhesion becomes too sensitive, resulting in poor image stability. Preferably, 0.9 ≦ Y ≦ 1.7 and α is −0.7 to −1.7.
The value of α and the value of β are determined by the type and amount of the pigment.
[0012]
The toner of the present invention preferably has a dielectric constant of 1.0 to 2.3, more preferably 1.0 to 2.0. The dielectric constant affects the transfer efficiency. When the dielectric constant is large and exceeds 2.3, the transfer efficiency tends to deteriorate.
The dielectric constant is determined by the dielectric constant of the binder resin, the type and amount of the additive, the melt-kneading conditions, and the like.
The true specific gravity of the toner of the present invention is preferably 0.90 to 1.15, more preferably 0.90 to 1.11, and still more preferably 0.90 to 1.08. The true specific gravity is related to the flying property, and the lower the true specific gravity, the better the flying property. If the true specific gravity exceeds 1.15, the flying property deteriorates, so that the image quality such as the denseness of the image deteriorates, the amount of adhered toner increases, and the toner consumption tends to increase.
The true specific gravity is determined by the true specific gravity of the binder resin, the type and amount of the additive, and the like.
[0013]
The toner of the present invention contains a colorant, and preferably contains 4.5 to 9.0% by weight in toner particles, and more preferably 4.5 to 7.0% by weight. If it is less than 4.5% by weight, the toner layer thickness on the developing roller is reduced, and the image density tends to decrease when the toner adhesion amount is low. If the content exceeds 9.0% by weight, the image quality (brightness) deteriorates and the change in image density in response to the change in the amount of toner adhered increases, and the image stability tends to deteriorate. In addition, contamination of the member due to the colorant may occur. There is.
[0014]
As the colorant, carbon black is used as a black pigment, and C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, C. 90, 112, 114, 122, 123, 163, 184, 202, 206, 207, 209; I. Pigment Violet 19; I. Buttlets 1, 2, 10, 13, 15, 23, 29, 35, and the like include C.I. I. Pigment Blue-2, 3, 15, 16, 17; I. Buttble-6; I. Acid Bull-45 and the like, as a yellow pigment, C.I. I. Pigment Yellow-1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 94, 97, 155, 180 Are used alone or as a mixture.
[0015]
The binder resin of the present invention may be selected so that the relationship between the amount of adhered toner and the image density satisfies the formula (1). can do. Examples of the binder resin include general polystyrene resins, polyacrylate resins, styrene-acrylate copolymer resins, styrene-methacrylate copolymer resins, polyvinyl chloride, and polyacetic acid as toner resins. Examples thereof include vinyl, polyvinylidene chloride, phenol resin, epoxy resin, polyester resin, hydrogenated rosin, cyclized rubber, polyolefin resin, and cycloolefin copolymer resin.
[0016]
Further, the binder resin is preferably selected so that the dielectric constant and the true specific gravity of the toner fall within the specified range. In order to set the toner adhesion amount, the dielectric constant, and the true specific gravity in a specific range, it is preferable to contain a polyolefin resin or a cycloolefin copolymer resin having a small dielectric constant or true specific gravity.
[0017]
Examples of the polyolefin resin include homopolymers and copolymers of olefin monomers, and specific examples thereof include polyethylene, polypropylene, polybutene, poly-3-methyl-1-butene, polypentene, and poly-5-methyl-1-hexene. , Polytetradecene, polypentadecene, polyheptadecene, polyoctadecene, polynonadecene, polyeicosene, and copolymers of monomer components of these polymers. Also, copolymers with acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, vinyl alcohol, vinyl acetate, maleic anhydride, styrene, vinyl chloride and the like can be mentioned.
[0018]
Cycloolefin copolymer resins are also preferred in terms of resin strength, transparency, and melting properties. The cycloolefin copolymer resin is, for example, an α-olefin (acyclic olefin in a broad sense) such as ethylene, propylene and butylene and an alicyclic compound having a double bond such as cyclohexene, norbornene and tetracyclododecene. (Cycloolefin). This cycloolefin copolymer resin is, for example, a polymer obtained by a polymerization method using a metallocene-based or Ziegler-based catalyst.
[0019]
Examples of the synthesis of the cycloolefin copolymer resin of the present invention are disclosed in JP-A-5-339327, JP-A-5-9223, JP-A-6-271628, and the like. Examples of using a cycloolefin copolymer resin in a toner are described in JP-A-9-101631, JP-A-2000-284528 and the like.
[0020]
In the present invention, it is preferable to contain a release agent. Examples of the wax as a release agent include polyolefin waxes such as polyethylene wax, polypropylene wax and modified polyethylene wax, synthetic waxes such as Fischer-Tropsch wax, petroleum waxes such as paraffin wax and micro wax, carnauba wax, candelilla wax. , Rice wax, hardened castor oil and the like. The amount of the wax added is preferably 1.0 to 8.0% by weight based on the whole toner particles. If the amount is less than 1.0% by weight, sufficient releasability cannot be obtained, and if the amount exceeds 8.0% by weight, filming or fusion is likely to occur.
[0021]
The charge control agent may be added as needed. Charge control agents added to impart polarity to toner are classified into those for positively charged toner and those for negatively charged toner. For positively charged toners, nigrosine dyes, quaternary ammonium salts, viridinium salts and azines, low molecular weight polymers having a cationic functional group and the like are used. For negatively charged toners, azo-based metal-containing complexes, salicylic acid-based metal complexes, boron-based metal complexes, low molecular weight polymers having an anionic functional group, and the like are used. The preferable addition amount is 0.1 to 5% by weight based on the whole toner particles. If it is less than 0.1% by weight, problems such as toner scattering due to poor charging tend to occur, and if it exceeds 5% by weight, image quality tends to deteriorate due to excessive charging. In the case of a full color toner, a colorless or light color toner is selected. The above charge control agents may be used alone or in combination.
[0022]
The toner particles constituting the present invention are produced by mixing the above-mentioned materials in a predetermined mixture, and then subjecting the mixture to a process such as melt-kneading, pulverization, and classification. Further, toner particles may be obtained by a polymerization method using the monomer of the binder resin and another material.
The volume average particle diameter of the toner of the present invention is preferably from 5.0 μm to 15.0 μm, more preferably from 7.0 to 10.0 μm. If it is less than 7.0 μm, image deterioration due to an increase in the amount of fine powder occurs, and if it exceeds 15.0 μm, image quality tends to deteriorate due to loss of denseness.
[0023]
In the toner of the present invention, it is preferable that the external additive adheres to the toner particles in a total amount of 1.0% by weight or more and 3.0% by weight or less. Regarding the type of the external additive, hydrophobic silica having a volume average particle diameter of 30 nm or more and 70 nm or less, silicone oil having a viscosity at 25 ° C. of 30 to 3000 CS, and a BET specific surface area of 30 m²/ G-100m²/ G of hydrophobic titanium oxide is preferably added. When the total amount of the external additives is less than 1.0% by weight, the external additives are easily fused to the photosensitive member and the charging member, and image defects are easily generated. If the content exceeds 3.0% by weight, an excessive amount of the external additive is separated from the toner and hinders the charging of the toner.
If the volume average particle diameter of the hydrophobic silica is less than 30 nm, the fusion resistance and image stability are likely to be impaired. If the volume average particle diameter exceeds 70 nm, the dispersibility of the silica itself in the toner matrix deteriorates, and the effect on the fusion resistance is reduced. It becomes a tendency. If the viscosity of the silicone oil is less than 30 CS, contamination in the machine due to an increase in volatile components tends to occur, and if it exceeds 3000 CS, the effect of improving the transfer efficiency is diminished. BET specific surface area of hydrophobic titanium oxide is 30m²/ G, the dispersibility in the toner matrix tends to deteriorate,²/ G tends to deteriorate the fusion resistance and the charge imparting property.
The hydrophobic silica fine particles may be used in combination with those having a smaller particle diameter. By adopting such an external additive formulation, more stable anti-fusing properties can be obtained.
[0024]
Toner such as alumina, talc, clay, calcium carbonate, magnesium carbonate, or various kinds of resin fine particles for controlling toner fluidity, chargeability, cleaning property, storage stability, etc. An additive may be attached.
In order to attach the fine particles to the toner particles, a method of mixing and stirring with a general stirrer such as a turbine type stirrer, a Henschel mixer, a super mixer, or the like may be used.
[0025]
Next, a non-magnetic one-component jumping developing method will be described as an example of the developing method of the present invention using the non-magnetic toner for electrophotography. FIG. 1 is a schematic configuration diagram of a developing device used in the non-magnetic one-component developing method of the present invention. In the figure, 1 is a photosensitive drum which is a cylindrical electrostatic latent image holding member, 2 is a hopper, 3 is a non-magnetic one-component developer, 4 is a layer regulating member, and 5 is a non-magnetic one-component developer. The developing roller 6 is a stirrer. In this developing device, an electrostatic latent image is formed on the photosensitive drum 1 by a known electrophotographic method. A non-magnetic one-component developer 3 is accommodated in the hopper 2, and the non-magnetic one-component developer 3 is carried on the sleeve of the developing roller 5 by the layer regulating member 4 so as to have a constant layer thickness. At the same time, electric charges are given by friction with the layer regulating member 4 and conveyed. A DC or AC bias voltage is applied to the developing roller. The non-magnetic one-component developer carried on the developing roller 5 is conveyed by the rotation of the developing roller 5, flies through a gap between the photosensitive drum 1 having an electrostatic latent image and a potential difference from the developing roller 5, and is exposed to light. The latent image is developed on the surface of the body drum 1 to visualize the electrostatic latent image.
As a member of the developing device constituting the present invention, a member usually used in a non-magnetic one-component developing method can be used. For example, metal, silicone rubber, urethane rubber, or the like can be used for the members of the developing roller and the charging blade.
[0026]
【Example】
Hereinafter, the present invention will be described based on examples and comparative examples. However, the present invention is not limited to these.
First, the following toners A to G were prepared.
[0027]
Example 1 <Production of Toner A>
-88.5 parts by weight of cycloolefin copolymer resin A
(Ticona, trade name: TOPAS COC, weight average molecular weight (Mw): 200,000, number average molecular weight (Mn): 5,000, Mw / Mn: 40)
・ 5.0 parts by weight of polypropylene wax
(Sanyo Kasei Kogyo Co., Ltd., product name: VISCOL 660P)
・ Azo zinc salt 2.0 parts by weight
(Orient Chemical Co., trade name: Bontron E-84)
・ 4.5 parts by weight of magenta pigment
(Manufactured by Clariant, trade name: Toner Magenta 6B, CI. Pigment Red 57-1)
The raw materials having the above mixing ratios are mixed with a super mixer, hot-melt kneaded with a biaxial extruder, pulverized with a jet mill, and then classified with a dry air classifier to obtain a toner having a volume average particle size of 9 μm. Particles were obtained.
Then, 0.3% by weight of a hydrophobic silica (trade name: RY-50, manufactured by Nippon Aerosil Co., Ltd.) having a volume average particle diameter of 40 nm with respect to the toner particles, and a medium diameter hydrophobic silica having a volume average particle diameter of 15 nm ( 1.0% by weight of Wacker Chemical Co., Ltd., trade name: H2000 / 4M) was added, and the mixture was mixed with a Henschel mixer at a peripheral speed of 40 m / sec for 4 minutes to obtain a toner A of the present invention.
[0028]
Example 2 <Production of Toner B>
Except that the cycloolefin copolymer resin was 85.0 parts by weight, the magenta pigment was 9.0 parts by weight, and the azo zinc complex salt was 1.0 part by weight, the toner B of the present invention was prepared in the same manner as in Example 1. Got.
[0029]
Example 3 <Production of Toner C>
A toner C of the present invention was obtained in the same manner as in Example 1 except that the magenta pigment was changed to Toner Magenta E02 (manufactured by Clariant, CI. Pigment Red 122).
[0030]
Example 4 <Production of Toner D>
A toner D of the present invention was obtained in the same manner as in Example 1 except that the magenta pigment was changed to permanent rubin F6B (manufactured by Clariant, CI. Pigment Red 184).
[0031]
Example 5 <Production of Toner E>
The binder resin is a linear low-density polyethylene resin (density 0.925 g / cm³The toner E of the present invention was obtained in the same manner as in Example 1 except that
[0032]
Example 6 (Production of Toner F)
Example 1 was repeated except that the binder resin was 53.0 parts by weight of the cycloolefin copolymer resin A used in Example 1 and 35.5 parts by weight of a polyester resin (trade name: FC-1142, manufactured by Mitsubishi Rayon Co., Ltd.). In the same manner as in the above, a toner F of the present invention was obtained.
[0033]
Comparative Example 1 <Production of Toner G>
Toner-G for comparison in the same manner as in Example 1 except that the cycloolefin copolymer resin was 88.0 parts by weight, the magenta pigment was 4.0 parts by weight, and the azo zinc complex salt was 3.0 parts by weight. Got.
[0034]
Comparative Example 2 <Preparation of Toner H>
A toner for comparison was prepared in the same manner as in Example 1, except that the cycloolefin copolymer resin A was 84.5 parts by weight, the magenta pigment was 9.5 parts by weight, and the azo zinc complex salt was 1.0 part by weight. H was obtained.
[0035]
Comparative Example 3 <Preparation of Toner I>
-83.5 parts by weight of cycloolefin copolymer resin B
(Ticona, trade name: TOPAS COC, weight average molecular weight (Mw): 15,000, number average molecular weight (Mn): 5,000, Mw / Mn: 3)
・ 5.0 parts by weight of polypropylene wax
(Sanyo Kasei Kogyo Co., Ltd., product name: VISCOL 660P)
・ Azo zinc salt 2.0 parts by weight
(Orient Chemical Co., trade name: Bontron E-84)
・ 9.5 parts by weight of magenta pigment
(Manufactured by Clariant, trade name: Toner Magenta 6B, CI. Pigment Red 57-1)
The raw materials having the above mixing ratios are mixed with a super mixer, hot-melt kneaded with a biaxial extruder, pulverized with a jet mill, and then classified with a dry air classifier to obtain a toner having a volume average particle size of 9 μm. Particles were obtained.
Then, 0.3% by weight of a hydrophobic silica (trade name: RY-50, manufactured by Nippon Aerosil Co., Ltd.) having a volume average particle diameter of 40 nm with respect to the toner particles, and a medium diameter hydrophobic silica having a volume average particle diameter of 15 nm ( 1.0% by weight of Wacker Chemical Co., Ltd., trade name: H2000 / 4M) was added, and the mixture was mixed with a Henschel mixer at a peripheral speed of 40 m / sec for 4 minutes to obtain a comparative toner I.
[0036]
Comparative Example 4 <Production of Toner J>
・ 90.0 parts by weight of polyester resin
(Mitsubishi Rayon Co., Ltd., trade name: FC-1142)
・ 5.0 parts by weight of polypropylene wax
(Sanyo Kasei Kogyo Co., Ltd., product name: VISCOL 660P)
・ Azo zinc salt 2.0 parts by weight
(Orient Chemical Co., trade name: Bontron E-84)
・ Magenta pigment 3.0 parts by weight
(Manufactured by Clariant, trade name: Toner Magenta 6B, CI. Pigment Red 57-1)
The raw materials having the above mixing ratios are mixed with a super mixer, hot-melt kneaded with a biaxial extruder, pulverized with a jet mill, and then classified with a dry air classifier to obtain a toner having a volume average particle size of 9 μm. Particles were obtained.
Then, 0.3% by weight of a hydrophobic silica (trade name: RY-50, manufactured by Nippon Aerosil Co., Ltd.) having a volume average particle diameter of 40 nm with respect to the toner particles, and a medium diameter hydrophobic silica having a volume average particle diameter of 15 nm ( 1.0% by weight of Wacker Chemical Co., Ltd., trade name: H2000 / 4M) was added, and mixed with a Henschel mixer at a peripheral speed of 40 m / sec for 4 minutes to obtain a comparative toner J.
[0037]
<Α, β of toner>
Α and β of the toner were determined by the following method, and the values are shown in Table 1.
Using each of the toners A to J, a fixed area (18 cm²) Was obtained. At this time, the toner adhesion amount on the transfer paper is adjusted to 0.4 to 0.8 mg / cm by adjusting the toner concentration of the developer, the surface potential of the photoreceptor, the development potential, the exposure amount, and the transfer conditions.²Was varied step by step. At this time, the amount of adhered toner was confirmed based on the weight before and after removing the unfixed toner from the transfer medium with an air gun. The adjusted unfixed image was fixed at the process speed of 125 mm / sec and the roller surface temperature of 180 ° C. by an external fixing device using a rubber roller on both the upper and lower sides. The image density of the fixed image was measured with a Macbeth reflection densitometer RD914. The test conditions were 25 ° C. and 55% RH.
The obtained image density and toner adhesion amount were graphed by Microsoft Excel, and a quadratic approximation curve and an equation were obtained from the graph to obtain α and β.
[0038]
<Dielectric constant of toner, true specific gravity>
The dielectric constant and the true specific gravity of the toner were determined by the following method, and the values are shown in Table 1.
1. How to measure dielectric constant
200 kg / cm of toner²Into a disk-shaped pellet having a diameter of 25 mm and a thickness of 4 to 4.5 mm, and set it on a SE-70 type solid electrode (manufactured by Ando Electric Co., Ltd.). Thereafter, the capacitance of the toner at 1 KHz was measured using a 2500A type capacitance bridge (manufactured by ANDEN-HAGERING), and the dielectric constant was calculated by the following equation.
Dielectric constant ε = C · d / ε₀
C: capacitance (pF)
d: thickness of pellet (mm)
ε₀: Dielectric constant in vacuum (8.86 × 10-12 pF / m)
S: Effective electrode area (mm²)
2. The true specific gravity of the toner was measured according to JIS K00615.2 Specific gravity bottle method.
[0039]
<Evaluation of toner>
The toners of the toners A to J of the embodiment and the comparative example are put into a developing machine of QMS2200 manufactured by Minolta QMS of a non-magnetic one-component jumping developing method, and an A4 document having an image ratio of 5% is transferred to A4 transfer paper. The image density (ID), fog (BG), toner consumption, transfer efficiency, and image vividness of each of the toners of Examples 1 to 6 and Comparative Examples 1 to 4 were determined at 25 ° C. and 55%. Evaluation was made under RH environmental conditions, and the results are shown in Tables 2 and 3.
[0040]
The evaluation method is as follows.
1. The image density (ID) of the solid image portion was measured with a Macbeth reflection densitometer RD-914. A practically acceptable level is 1.10 to 1.90.
2. Fog (BG) was measured by measuring the whiteness of the non-image area with a color meter ZE2000 manufactured by Nippon Denshoku Industries Co., Ltd., and indicated by the difference in whiteness before and after copying. The practically acceptable level is 0.70 or less.
3. The toner consumption was determined by the total consumption after copying 6,000 sheets from the toner reduction amount from the developing device every 1000 sheets. The target value is 115 g or less.
4. Average transfer efficiency: The transfer efficiency was determined from the difference between the amount of toner consumed and the amount of collected toner for every 1000 copies, and averaged up to 6000 copies. The target value is 75% or more.
Transfer efficiency (%) = (toner consumption−recovered toner amount) × 100 / toner consumption
5. The vividness of the image was visually observed.
：: Image color is vivid ×: Image color is dull
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
[Table 3]

[0044]
<Evaluation results>
As is clear from Tables 2 and 3, with the toners of Examples 1 to 6 of the present invention, the image density after 6000 sheets from the initial stage is 1.10 to 1.90, and the fog is 0.70 or less, and practical use is possible. It was confirmed that copying was possible within a range without any problem, the toner consumption was 115 g or less / 6000 sheets, the average transfer efficiency was 75% or more, the image was vivid, and there was no practical problem. On the other hand, the toner of Comparative Example 1 had a small β and a low image density.
On the other hand, in the toner of Comparative Example 2, α was small, β was large, toner consumption was large, transfer efficiency was small, and fog was slightly large. The toner of Comparative Example 3 had a large α, an excessive image density, and inferior image vividness. In the toner of Comparative Example 4, α was large, β was small, toner consumption was large, transfer efficiency was small, and image density was slightly small.
[0045]
【The invention's effect】
As described above, the present invention has high transfer efficiency, does not cause insufficient image density, and has problems such as fusion even if the toner consumption is low (low toner layer thickness and low toner adhesion amount). An epoch-making effect that a non-magnetic toner for electrophotography which does not occur even during continuous printing of a large number of sheets, has good developing properties, has high durability, and consumes low amount, and a developing method using the same can be provided. To play.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of an example of an apparatus used in a developing method of the present invention.
FIG. 2 is a graph showing a relation of the formula (1) in the first embodiment of the present invention.
FIG. 3 is a graph showing the relationship of the expression (1) in the second embodiment of the present invention.
FIG. 4 is a graph showing the relationship of the expression (1) in Comparative Example 2.
FIG. 5 is a graph showing the relationship of the formula (1) in Comparative Example 3.
[Explanation of symbols]
1 Photoconductor drum
2 Hopper
3 Non-magnetic one-component developer
Four-layer regulating member
5 Developing roller
6 stirrer
7 Power supply

Claims (6)

The image density Y is 0.9 ≦ Y ≦ 1.9 when at least a binder resin and a colorant are contained, and the toner adhesion amount X (mg / cm ² ) on the transfer medium is in the range of 0.4 to 0.8. Wherein the α in the following formula (1) satisfies -0.4 to -1.8 and β satisfies 2.4 to 3.2.

2. The non-magnetic toner for electrophotography according to claim 1, wherein the dielectric constant is 1.0 to 2.3 and the true specific gravity is 0.90 to 1.15. At least one of hydrophobic silica having a volume average particle diameter of 30 to 70 nm, silicone oil having a viscosity at 25 ° C. of 30 to 3000 CS, and hydrophobic titanium oxide having a BET specific surface area of 30 to 100 m ² / g is externally added. 3. The non-magnetic toner for electrophotography according to claim 1, wherein the toner is used as an agent, and the total amount of the external additives is 1.0 to 3.0% by weight based on the toner particles. . 4. The non-magnetic toner for electrophotography according to claim 1, wherein the toner is used in a non-magnetic one-component jumping development method. The non-magnetic toner for electrophotography according to any one of claims 1 to 4, wherein the toner is for full color use. The image density Y is 0.9 ≦ Y ≦ 1.9 when at least a binder resin and a colorant are contained, and the toner adhesion amount X (mg / cm ² ) on the transfer medium is in the range of 0.4 to 0.8. The non-magnetic toner for electrophotography is characterized in that α in the following formula (1) satisfies -0.4 to -1.8 and β satisfies 2.4 to 3.2. A non-magnetic one-component jumping developing method to be fine.

Images