JP4414121B2 - Toner for electrophotography - Google Patents

Description

【００１１】
（式中、Ｒは炭素数２〜３のアルキレン基、ｘ及びｙは正の数を示し、ｘとｙの和は１〜１６、好ましくは１．５〜５．０である）
で表されるビスフェノールＡのアルキレンオキサイド付加物が含有されているのが好ましい。
【００１２】
式（Ｉ）で表されるビスフェノールＡのアルキレンオキサイド付加物としては、ポリオキシプロピレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシエチレン（２．０）−２，２−ビス（４−ヒドロキシフェニル）プロパン等のビスフェノールＡのアルキレン（炭素数２〜３）オキサイド（平均付加モル数１〜１６）付加物等が挙げられる。
【００１３】
式（Ｉ）で表されるビスフェノールＡのアルキレンオキサイド付加物のアルコール成分中の含有量は、低温定着性と耐久性を両立させる観点から、５モル％以上、好ましくは５０モル％以上、より好ましくは１００モル％である。
【００１４】
また、ビスフェノールＡのアルキレンオキサイド付加物以外のアルコール成分としては、エチレングリコール、プロピレングリコール、グリセリン、ペンタエリスリトール、トリメチログリコールプロパン、水素添加ビスフェノールＡ、ソルビトール、又はそれらのアルキレン（炭素数２〜４）オキサイド（平均付加モル数１〜１６）付加物等が挙げられ、これは単独でまたは２種以上を混合して用いることができる。
【００１５】
ポリエステルは、例えば、アルコール成分とカルボン酸成分とを不活性ガス雰囲気中にて、要すればエステル化触媒を用いて、１８０〜２５０℃の温度で縮重合することにより製造することができる。
【００１６】
ポリエステルの軟化点は、８０〜１６５℃が好ましく、ガラス転移点は５０〜８５℃が好ましい。また、ポリエステルの酸価は、０．５〜６０ｍｇＫＯＨ／ｇが好ましく、水酸基価は、１〜６０ｍｇＫＯＨ／ｇが好ましい。
【００１７】
結着樹脂中のポリエステルの含有量は、５０〜１００重量％が好ましく、８０〜１００重量％がより好ましく、１００重量％が特に好ましい。さらに、結着樹脂中には、スチレン−アクリル樹脂、ハイブリッド樹脂、エポキシ樹脂、ポリカーボネート、ポリウレタン等のポリエステル以外の樹脂が適宜含有されていてもよい。
【００１８】
蛍光剤としては、紫外及び可視部の励起光線により蛍光を発する顔料、染料を特に限定することなく例示することができ、さらに光線による刺激を除いたあとも蛍光を発する蓄光蛍光体であってもよい。
【００１９】
蛍光剤の具体例としては、無機蛍光顔料、例えば、タングステン酸カルシウム、ヒ酸マグネシウムカルシウム、ケイ酸バリウム、リン酸カルシウム及びリン酸カルシウム亜鉛等のアルカリ土類金属の硫化物、ケイ酸塩、リン酸塩、タングステン酸塩；有機蛍光顔料；有機蛍光染料、例えば、４，４’−ビス（４−フェニル−１，２，３−トリアゾール−２−イル）スチルベン−２’，２’−ジスルホン酸ナトリウム、３−フェニル−７−（４−メチル−５−フェニル−１，２，３−トリアゾール−２−イル）クマリン、３−フェニル−７−（２Ｈ−ナフト〔１，２−ｄ〕−トリアゾール−２−イル）クマリン、１−（４−アシドスルホニルフェニル）−３−（４−クロロフェニル）−２−ピラゾリン等のクマリン誘導体、ナフタールイミド誘導体、スチルベン誘導体、ベンゾチアゾール誘導体、ベンゾイミダゾール誘導体、ベンゾオキサゾール誘導体、ベンジジン誘導体等が挙げられ、これらの中ではクマリン誘導体及びナフタールイミド誘導体が好ましく、クマリン誘導体がより好ましい。
【００２０】
蛍光剤自体は、やや色を有していてもよいが、電子複写物の模様、色彩等の外観に悪影響を与えないように、少なくとも、トナーにした場合に可視光下では無色ないし白色であることが好ましい。このような観点から、蛍光剤の波長ピークは、４２０ｎｍ以下が好ましく、４〜４００ｎｍがより好ましい。
【００２１】
蛍光剤の含有量は、結着樹脂１００重量部に対して、０．１〜１０重量部が好ましく、０．５〜５重量部がより好ましい。
【００２２】
本発明のトナーには、結着樹脂及び蛍光剤に加えて、着色剤、荷電制御剤、離型剤、流動性向上剤、導電性調整剤、体質顔料、繊維状物質等の補強充填剤、酸化防止剤、老化防止剤、クリーニング性向上剤等の添加剤が適宜含有されていてもよい。
【００２３】
本発明のトナーの製造方法は、混練粉砕法、重合法等の従来より公知のいずれの方法であってもよいが、例えば、混練粉砕法による粉砕トナーの場合、結着樹脂、蛍光剤等をボールミル等の混合機で均一に混合した後、密閉式ニーダー又は１軸もしくは２軸の押出機等で溶融混練し、冷却、粉砕、分級して製造することができる。トナーの体積平均粒子径は、３〜１５μｍが好ましい。さらに、トナーの表面には、疎水性シリカ等の流動性向上剤等が外添剤として添加されていてもよい。
【００２４】
本発明の電子写真用トナーは、磁性体微粉末を含有するときは単独で現像剤として、また磁性体微粉末を含有しないときは非磁性一成分系現像剤として、もしくはキャリアと混合して二成分系現像剤として使用され得る。
【００２５】
【実施例】
〔軟化点〕
高化式フローテスター「ＣＦＴ−５００Ｄ」（島津製作所製）を用い、樹脂の半分が流出する温度を軟化点とする（試料：１ｇ、昇温速度：６℃／分、荷重：１．９６ＭＰａ、ノズル：１ｍｍφ×１ｍｍ）。
【００２６】
〔酸価〕
ＪＩＳ Ｋ００７０の方法により測定する。
【００２７】
〔ガラス転移点〕
示差走査熱量計「ＤＳＣ２１０」（セイコー電子工業（株）製）を用いて昇温速度１０℃／分で測定する。
【００２８】
樹脂製造例
表１に示す原料を窒素雰囲気下、２３０℃で攪拌しつつ、ＡＳＴＭ Ｄ３６−８６により測定した軟化点がそれぞれ所定の温度に達するまで反応させて、ポリエステル１〜４を得た。
また、「ハイマーＳＢＭ−７３Ｆ」（三洋化成（株）製）をスチレン−アクリル樹脂１として、表１に合わせて示す。
【００２９】
【表１】

【００３０】
実施例１〜３、比較例１、２
表２に示す結着樹脂１００重量部、蛍光剤１．０重量部及び荷電制御剤「ボントロン Ｅ−８４」（オリエント化学工業社製）１．０重量部をヘンシェルミキサーにて混合し、２軸押出機で溶融混練して、冷却後、粉砕、分級工程を行い、体積平均粒子径が９μｍの粉体を得た。
【００３１】
得られた粉体１００重量部と疎水性シリカ「Ｒ−９７２」（日本アエロジル社製）０．３重量部をヘンシェルミキサーで攪拌混合してトナーを得た。
【００３２】
【表２】

【００３３】
試験例
「ＣＯＬＯＲ ＰＡＧＥＰＲＥＳＴＯ Ｎ４」（カシオ電子工業社製）にトナーを実装し、５ｃｍ四方のベタ画像を印刷した。得られたベタ画像を日の当たる窓際に張りつけ、３ヵ月間自然光に暴露した。１ヵ月後、２ヵ月後、３ヵ月後に、ブラックライトを画像に照射し、発光の程度を目視にて判断した。以下の評価基準に従って、耐光性を評価した結果を表３に示す。
【００３４】
〔評価基準〕
◎：変化なし
○：やや発光低下があるも問題なし
△：発光低下が認められる
×：ほとんど発光が認められない
【００３５】
【表３】

【００３６】
以上の結果より、実施例のトナーと比較して、芳香族系カルボン酸化合物を使用せずに得られたポリエステルを含有した比較例１のトナー及び結着樹脂としてポリエステルを含有していない比較例２のトナーは、時間とともに、発光の低下が著しいことが分かる。
【００３７】
【発明の効果】
本発明により、紫外線照射下で発光し、かつ耐光性に優れた電子写真用トナーを提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.
[0002]
[Prior art]
In recent years, with the development of copying technology, many toners containing a fluorescent agent have been reported for the purpose of preventing unauthorized copying and protecting confidential documents (Japanese Patent Laid-Open Nos. 58-14842 and 57-66441). No. 1, JP-A-1-126659, JP-A-1-201677, etc.). However, a toner containing a fluorescent agent has a drawback that it has a low light resistance and does not develop color when exposed to sunlight for a long time.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide an electrophotographic toner that emits light under ultraviolet irradiation and is excellent in light resistance.
[0004]
[Means for Solving the Problems]
The present invention relates to a toner for electrophotography comprising a binder resin and a fluorescent agent, wherein the binder resin comprises an alcohol component and a divalent or higher valent aromatic carboxylic acid compound. The present invention relates to an electrophotographic toner comprising a polyester obtained by condensation polymerization.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The toner of the present invention is characterized in that it contains a polyester using a specific carboxylic acid component as a binder resin. That is, the light resistance of the toner is remarkably improved by using the fluorescent agent in combination with a polyester obtained by using a divalent or higher aromatic carboxylic acid compound as the carboxylic acid component.
[0006]
Examples of the divalent or higher aromatic carboxylic acid compounds include phthalic acid carboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid, trimellitic acid, pyromellitic acid, alkyl (1 to 3 carbon atoms) esters thereof, and anhydrides thereof. The thing etc. are mentioned, This can be used individually or in mixture of 2 or more types. Of these, phthalic acid-based carboxylic acid compounds are preferred, terephthalic acid compounds are more preferred, and terephthalic acid is particularly preferred.
[0007]
The content of the aromatic carboxylic acid compound is preferably 10 mol% or more, more preferably 30 to 100 mol%, particularly preferably 50 to 100 mol%, and most preferably 90 to 100 mol% in the carboxylic acid component.
[0008]
Examples of carboxylic acid components other than aromatic carboxylic acid compounds include dicarboxylic acids such as fumaric acid and maleic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octyl succinic acid, or alkenyl groups having 2 to 20 carbon atoms. Examples thereof include substituted succinic acid, anhydrides of these acids, and alkyl (C1 to C3) esters of these acids, and these can be used alone or in admixture of two or more.
[0009]
The alcohol component of the polyester includes the formula (I):
[0010]
[Chemical 1]

[0011]
(Wherein R is an alkylene group having 2 to 3 carbon atoms, x and y are positive numbers, and the sum of x and y is 1 to 16, preferably 1.5 to 5.0)
It is preferable that the alkylene oxide addition product of bisphenol A represented by these is contained.
[0012]
Examples of the alkylene oxide adduct of bisphenol A represented by the formula (I) include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2. And alkylene (carbon number 2 to 3) oxide (average number of moles 1 to 16) adduct of bisphenol A such as 2-bis (4-hydroxyphenyl) propane.
[0013]
The content of the alkylene oxide adduct of bisphenol A represented by formula (I) in the alcohol component is 5 mol% or more, preferably 50 mol% or more, more preferably from the viewpoint of achieving both low-temperature fixability and durability. Is 100 mol%.
[0014]
Examples of the alcohol component other than the alkylene oxide adduct of bisphenol A include ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethyloglycol propane, hydrogenated bisphenol A, sorbitol, or alkylene thereof (2 to 4 carbon atoms). An oxide (average addition mole number 1-16) adduct etc. are mentioned, This can be used individually or in mixture of 2 or more types.
[0015]
The polyester can be produced, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst.
[0016]
The softening point of the polyester is preferably 80 to 165 ° C, and the glass transition point is preferably 50 to 85 ° C. The acid value of the polyester is preferably 0.5 to 60 mgKOH / g, and the hydroxyl value is preferably 1 to 60 mgKOH / g.
[0017]
The content of the polyester in the binder resin is preferably 50 to 100% by weight, more preferably 80 to 100% by weight, and particularly preferably 100% by weight. Further, the binder resin may appropriately contain a resin other than polyester such as styrene-acrylic resin, hybrid resin, epoxy resin, polycarbonate, polyurethane and the like.
[0018]
Examples of the fluorescent agent include pigments and dyes that emit fluorescence by excitation light in the ultraviolet and visible regions, without any particular limitation, and even phosphorescent phosphors that emit fluorescence even after removal of light stimulus. Good.
[0019]
Specific examples of fluorescent agents include inorganic fluorescent pigments such as sulfides of alkaline earth metals such as calcium tungstate, magnesium calcium arsenate, barium silicate, calcium phosphate and calcium zinc phosphate, silicates, phosphates, tungsten Organic fluorescent pigments; organic fluorescent dyes such as sodium 4,4′-bis (4-phenyl-1,2,3-triazol-2-yl) stilbene-2 ′, 2′-disulfonate, 3- Phenyl-7- (4-methyl-5-phenyl-1,2,3-triazol-2-yl) coumarin, 3-phenyl-7- (2H-naphtho [1,2-d] -triazol-2-yl ) Coumarin, 1- (4-Acidsulfonylphenyl) -3- (4-chlorophenyl) -2-pyrazoline and other coumarin derivatives, naphthalimide derivatives Stilbene derivatives, benzothiazole derivatives, benzimidazole derivatives benzoxazole derivatives, benzidine derivatives and the like, coumarin derivatives and naphthalimide derivatives preferably Among them, a coumarin derivative is more preferred.
[0020]
The fluorescent agent itself may have a slight color, but is at least colorless or white under visible light when used as a toner so as not to adversely affect the appearance of the electronic copy, such as the pattern and color. It is preferable. From such a viewpoint, the wavelength peak of the fluorescent agent is preferably 420 nm or less, and more preferably 4 to 400 nm.
[0021]
The content of the fluorescent agent is preferably 0.1 to 10 parts by weight and more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the binder resin.
[0022]
In the toner of the present invention, in addition to the binder resin and the fluorescent agent, a colorant, a charge control agent, a release agent, a fluidity improver, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, Additives such as an antioxidant, an anti-aging agent, and a cleaning property improver may be appropriately contained.
[0023]
The method for producing the toner of the present invention may be any conventionally known method such as a kneading and pulverizing method or a polymerization method. For example, in the case of a pulverized toner by the kneading and pulverizing method, a binder resin, a fluorescent agent, etc. After uniformly mixing with a mixer such as a ball mill, it can be manufactured by melt-kneading with a closed kneader or a single or twin screw extruder, cooling, pulverizing and classifying. The volume average particle diameter of the toner is preferably 3 to 15 μm. Furthermore, a fluidity improver such as hydrophobic silica may be added to the surface of the toner as an external additive.
[0024]
The electrophotographic toner of the present invention can be used alone as a developer when containing magnetic fine powder, or as a non-magnetic one-component developer when not containing magnetic fine powder, or mixed with a carrier. It can be used as a component developer.
[0025]
【Example】
[Softening point]
Using Koka-type flow tester “CFT-500D” (manufactured by Shimadzu Corporation), the temperature at which half of the resin flows out is defined as the softening point (sample: 1 g, heating rate: 6 ° C./min, load: 1.96 MPa, Nozzle: 1 mmφ × 1 mm).
[0026]
[Acid value]
It is measured by the method of JIS K0070.
[0027]
[Glass transition point]
A differential scanning calorimeter “DSC210” (manufactured by Seiko Denshi Kogyo Co., Ltd.) is used to measure at a heating rate of 10 ° C./min.
[0028]
Resin Production Examples While stirring the raw materials shown in Table 1 at 230 ° C. in a nitrogen atmosphere, the softening points measured by ASTM D36-86 were each reacted until reaching a predetermined temperature to obtain polyesters 1 to 4.
Further, “Hymer SBM-73F” (manufactured by Sanyo Chemical Co., Ltd.) is shown as styrene-acrylic resin 1 in accordance with Table 1.
[0029]
[Table 1]

[0030]
Examples 1 to 3, Comparative Examples 1 and 2
100 parts by weight of binder resin shown in Table 2, 1.0 part by weight of fluorescent agent, and 1.0 part by weight of charge control agent “Bontron E-84” (manufactured by Orient Chemical Co., Ltd.) were mixed in a Henschel mixer, and biaxial After melt-kneading with an extruder and cooling, pulverization and classification steps were performed to obtain a powder having a volume average particle size of 9 μm.
[0031]
100 parts by weight of the obtained powder and 0.3 parts by weight of hydrophobic silica “R-972” (manufactured by Nippon Aerosil Co., Ltd.) were stirred and mixed with a Henschel mixer to obtain a toner.
[0032]
[Table 2]

[0033]
A toner was mounted on a test example “COLOR PAGERESTO N4” (manufactured by Casio Electronics Co., Ltd.), and a solid image of 5 cm square was printed. The obtained solid image was attached to a window in the sun and exposed to natural light for 3 months. After 1 month, 2 months, and 3 months, the image was irradiated with black light, and the degree of light emission was judged visually. The results of evaluating light resistance according to the following evaluation criteria are shown in Table 3.
[0034]
〔Evaluation criteria〕
◎: No change ○: Slight decrease in light emission but no problem △: Reduction in light emission is recognized ×: Almost no light emission is recognized [0035]
[Table 3]

[0036]
From the above results, the toner of Comparative Example 1 containing a polyester obtained without using an aromatic carboxylic acid compound and the Comparative Example not containing a polyester as a binder resin as compared with the toners of Examples. It can be seen that the toner No. 2 has a remarkable decrease in light emission with time.
[0037]
【The invention's effect】
According to the present invention, an electrophotographic toner that emits light under ultraviolet irradiation and has excellent light resistance can be provided.

Claims (5)

An electrophotographic toner that contains a binder resin and a fluorescent agent, does not contain a colorant, and is colorless or white under visible light , wherein the binder resin comprises an alcohol component and a divalent or higher aromatic carboxyl a carboxylic acid component comprising an acid compound Ri name contains a polyester obtained by polycondensing, the fluorescent agent electrophotographic toner Ru coumarin derivative or naphthalimide derivatives der.   2. The electrophotographic toner according to claim 1, wherein the fluorescent agent is contained in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The toner for electrophotography according to claim 1 or 2, wherein the aromatic carboxylic acid compound is a phthalic acid carboxylic acid compound. Claim 1-3 electrophotographic toner according to any one content is carboxylic acid component 10 mol% or more aromatic carboxylic acid compound. The alcohol component is of formula (I):

(Wherein R is an alkylene group having 2 to 3 carbon atoms, x and y are positive numbers, and the sum of x and y is 1 to 16), an alkylene oxide adduct of bisphenol A represented by 50 The toner for electrophotography according to any one of claims 1 to 4, wherein the toner is contained in a mol% or more.