JP3748493B2 - Electrophotographic transfer paper - Google Patents

Description

【００２０】
で表わされるテレフタル酸単位を含む芳香族二塩基酸成分の繰返し単位、並びに、下記（ｂ）：
【００２１】
【化２】

【００２２】
で表わされるエチレングリコール単位、下記（ｃ）：
【００２３】
【化３】

【００２４】
で表わされるトリエチレングリコール単位、及び下記（ｄ）：
【００２５】
【化４】

【００２６】
（但し、ｎは、１〜５を表わす。）で表わされるビスフェノールＡのエチレンオキサイド付加物単位を含む二価アルコール成分の繰り返し単位、を有していることが好ましい。
このような芳香族ポリエステル樹脂としては、例えば、下記式で表される「ＳＴＡＦＩＸ Ｆ−ＬＣ」（富士写真フイルム（株）製）が好ましく挙げられる。
【００２７】
【化５】

【００２８】
また、前記芳香族ポリエステル樹脂は、下記（ｅ）：
【００２９】
【化６】

【００３０】
で表わされるテレフタル酸単位を含む芳香族二塩基酸成分の繰返し単位、並びに、下記（ｆ）：
【００３１】
【化７】

【００３２】
で表わされるテトラメチレングリコール単位、及び下記（ｇ）：
【００３３】
【化８】

【００３４】
で表わされるポリテトラメチレングリコール単位を含む二価アルコール成分の繰り返し単位、を有していることが好ましい。
このような芳香族ポリエステル樹脂としては、例えば、「ハイトレル」（東レ−Ｄｕｐｏｎｔ製）、「グリラックス」（大日本インキ化学工業製）、「ペルプレン」（東洋紡製）等が好ましく挙げられる。
【００３５】
上記の芳香族ポリエステル樹脂は、通常のポリエチレンテレフタレートあるいはポリエチレン−２，６−ナフタレートの合成と同様に、二塩基酸と二価アルコールをエステル化反応もしくはエステル交換反応させることによりオリゴマーを得、次いで真空下で重縮合反応を行って合成することができる。また、特公昭５３−３７９２０号公報に記載のようにポリエステルの解重合法によっても得ることができる。また、二塩基酸としては、ジメチルテレフタレート、ジメチルイソフタレート、ジメチル−２，６−ナフタレンカルボキシレート等のジカルボン酸のアルキルエステルを少なくとも一方に用いてエステル交換反応を行なった後、重縮合反応を行なっても、ジカルボン酸を用いて直接エステル化、次いで重縮合反応を行なってもよい。
【００３６】
例えば、二塩基酸と二価アルコールを、大気圧下１８０〜２８０℃で１２０〜２４０分反応させ、水又はアルコールの留出を終了させて、エステル交換反応を完結させる。次いで、反応系内の圧力を１ｍｍＨｇ以下の高真空にすると共に、２４０〜２９０℃に昇温し、この温度にて６０〜１８０分間加熱して芳香族ポリエステル樹脂を得る。
【００３７】
前記芳香族ポリエステル樹脂の数平均分子量は、１５００〜５０００の範囲が好ましい。また前記芳香族ポリエステル樹脂の重量平均分子量は、２５００〜１５０００の範囲が好ましい。前記芳香族ポリエステル樹脂の（重量平均分子量／数平均分子量）は、１．２〜３．０の範囲にあることが好ましい。
【００３８】
（無機顔料）
本発明においては、白色度を向上させ、画像を鮮明にする目的から、前記被転写層に無機顔料を添加することが好ましい。
前記無機顔料としては、例えば、酸化チタン、硫酸バリウム、酸化亜鉛、タルク、炭酸カルシウム、酸化アルミニウム、酸化ケイ素等の粉末、これらの固溶体等を用いることができ、また、群青等の青色系又はバイオレット系の顔料を用いることもできる。無機顔料の粒子径は、０．０４〜１μｍ程度である。粒子径が０．０４μｍよりも小さいと、無機顔料を樹脂に均一に分散させるのが困難であり好ましくない。また、粒子径が１μｍよりも大きいと、組成物の被覆膜表面が粗くなりすぎて画質の低下をきたすので好ましくない。
また、無機顔料の添加量は、前記樹脂組成物に対して、１〜３０重量％が好ましく、３〜１０重量％がより好ましい。添加量が１重量％より少ないと、白色度を向上させる効果が不良となる場合があり、一方、添加量が３０重量％より多いと、ラミネート膜の安定性が不良となる場合がある。
これらの無機顔料の中で、酸化チタン及び硫酸バリウムが白色度の点から好ましく、好ましい平均粒径は０．１〜０．８μｍである。用いられる無機顔料の具体的商品名としては、チタン工業製のＫＡ−１０、ＫＡ−２０等が挙げられる。
【００３９】
（その他の成分）
前記被転写層には、本発明の効果を損なわない限り、層の特性を制御する目的で、その他の成分を添加することができる。
前記被転写層を構成する樹脂組成物には、前記ポリエチレンテレフタレートと前記芳香族ポリエステル樹脂以外に、被転写層全成分の２０重量％以下の範囲で他のポリマーを含んでもよい。併用されるポリマーとしては、一般にガラス転移温度６０℃以上（好ましくは、６０〜１２０℃）のものが使用される。例えば、上記以外のポリエステル樹脂、ポリエーテル樹脂、アクリル樹脂、エポキシ樹脂、ウレタン樹脂、アミノ樹脂、フェノール樹脂等が挙げられる。
【００４０】
前記被転写層には、その他の成分として、フィラー、マット剤、蛍光増白剤、離型剤、褪色防止剤等を含有させることができる。
前記フィラーは、摩擦係数を調整する目的で添加することができる。フィラーとしては、シリカ、アルミナ、炭酸カルシウム等が挙げられる。
これらの顔料やフィラーを、被転写層を形成する樹脂組成物中に添加する方法としては、特に制限はなく、例えば、樹脂を溶融押出しする際に直接に押出し機中に添加する方法、予めマスターペレットを作成してそれを添加する方法等、公知の好適な方法を適用することができる。
【００４１】
前記マット剤の添加は、滑り性を向上させることができるので、耐摩耗性及び耐傷性においても良好な効果を与える。前記マット剤に使用される材料としては、フッ素系樹脂、低分子量ポリオレフィン系有機ポリマー（例えば、ポリエチレン系マット剤、パラフィン系又はマイクロクリスタリン系のワックスエマルジョン）、略球状のマット剤に使用される材料としては、ビーズ状プラスチックパウダー（材料例、架橋型ＰＭＭＡ、ポリカーボネート、ポリエチレンテレフタレート、ポリエチレン又はポリスチレン）、及び無機微粒子（例えば、ＳｉＯ₂ 、Ａｌ₂ Ｏ₃ 、タルク又はカオリン）が挙げられる。前記マット剤の含有量は、樹脂組成物に対して０．１〜１０重量％が好ましい。
【００４２】
前記蛍光増白剤の例としては、Ｋ．Ｖｅｅｎｋａｔａｒａｍａｎ編「ザ ケミストリー オブ シンセチック ダイズ（Ｔｈｅ Ｃｈｅｍｉｓｔｒｙ ｏｆｓｙｎｔｈｅｔｉｃ ｄｙｅｓ）」第Ｖ巻、第８章、特開昭６１−１４３７５２号公報等に記載されている化合物が挙げられる。
具体的には、スチルベン系化合物、クマリン系化合物、ビフェニル系化合物、ベンゾオキサゾリル系化合物、ナフタルイミド系化合物、ピラゾリン系化合物、カルボスチリル系化合物、２，５−ジベンゾオキサゾールチオフェン系化合物等が挙げられる。蛍光増白剤は褪色防止剤と組み合わせて用いることができる。
【００４３】
前記離型剤としては、ポリエチレンワックス、アミドワックス、シリコン系樹脂の微粉末、フッ素系樹脂の微粉末等の固形あるいはワックス状物質：フッ素系、リン酸エステル系等の界面活性剤：パラフィン系、シリコーン系、フッ素系のオイル類等、従来公知の離型剤がいずれも使用できる。
【００４４】
前記褪色防止剤としては、例えば、酸化防止剤、紫外線吸収剤、又はある種の金属錯体を用いることができる。
酸化防止剤としては、例えば、クマロン系化合物、クマラン系化合物、フェノール系化合物（例えば、ヒンダードフェノール類）、ハイドロキノン誘導体、ヒンダードアミン誘導体、スピロインダン系化合物が挙げられる。また、特開昭６１−１５９６４４号公報に記載の化合物も有効である。
【００４５】
紫外線吸収剤としては、例えば、ベンゾトリアゾール系化合物（米国特許第３５３３７９４号公報等に記載）、４−チアゾリドン系化合物（米国特許第３３５２６８１号公報等に記載）ベンゾフェノン系化合物（特開昭５６−２７８４号公報等に記載）、その他、特開昭５４−４８５３５号、同６２−１３６６４１号、同６１−８８２５６号等の公報に記載の化合物がある。また、特開昭６２−２６０１５２号公報に記載の紫外線吸収性ポリマーも有効である。
【００４６】
金属錯体としては、米国特許第４２４１１５５号、同４２４５０１８号（第３〜３６欄）、同第４２５４１９５号（第３〜８欄）、特開昭６２−１７４７４１号、同６１−８８２５６号（第２７〜２９頁）、特開平１−７５５６８号、特開昭６３−１９９２４８号等の公報に記載されている化合物がある。
【００４７】
有用な褪色防止剤の例は、具体的には、特開昭６２−２１５２７２号公報（第１２５〜１３７頁）に記載されている。
被転写層に含有させる褪色防止剤としては、無機物の微粉末が好ましい。具体的には酸化チタン、酸化亜鉛等の微粉末であり、好ましい粒径は、６００ｎｍ程度である。これらの微粉末の含有量は、被転写層形成成分の全量の０．１〜５０重量％であることが好ましく、０．１〜２０重量％がより好ましい。
上記の褪色防止剤として使用される酸化防止剤、紫外線吸収剤、金属錯体は、それぞれを一種単独で用いてもよく、二種以上併用してもよい。これら異なる褪色防止を組み合わせて使用してもよい。
【００４８】
前記被転写層には、塗布助剤として、又は、剥離性改良、滑り性改良、帯電防止等の目的で種々の界面活性剤を使用することができる。
界面活性剤としては、非イオン性界面活性剤、アニオン性界面活性剤、両性界面活性剤、カチオン性界面活性剤のいずれも用いることができる。これらの具体例は、特開昭６２−１７３４６３号、同６２−１８３４５７号等の公報に記載されている。
【００４９】
（溶融押出し法等）
本発明の電子写真用被転写紙における被転写層は、溶融押出し法により形成される。溶融押出し法においては、加熱された押出し機から広幅のスリットダイ（いわゆるＴ−ダイ）を経て押し出された溶融樹脂膜を、支持体に接触させローラーで連続的に圧接するラミネート方法や、同じく溶融樹脂を冷却ロール上に押出し、巻き取ってフイルム化する一般的な方法等が挙げられる。溶融押出し法によれば、支持体上に、前記樹脂組成物からなる均一な膜を容易に形成することができる。
溶融押出し法による被転写層の形成に使用する押出し機は、一軸のものでも、二軸のものでもよいが、前記ポリエチレンテレフタレートと前記芳香族ポリエステル樹脂とを均一に混合しうる能力を有するものであることが重要である。
【００５０】
前記被転写層は、支持体の一方の表面あるいは両方の表面に形成することができる。
前記被転写層の層厚は、２０〜４５μｍの範囲が好ましく、２３〜３５μｍの範囲がより好ましい。層厚が２０μｍより薄いと、支持体への密着悪化やトナーの埋め込みが悪くなることがある。一方、層厚が４５μｍより厚いと、剛度が高くなりすぎ、例えば、プリンターを通過させるときにジャミングが起こることがある。
【００５１】
前記被転写層は、１×１０⁹ 〜１×１０¹³Ωの範囲（２５℃、６５％ＲＨの条件にて）の表面電気抵抗を有することが好ましい。１×１０⁹ Ω未満の場合は、電子写真用被転写紙の被転写層にトナーが転写される際のトナー量が充分でなく得られるトナー画像の濃度が低くなることがある。一方、１×１０¹³Ωを超える場合は、転写時に必要以上の電荷が発生しトナーが充分に転写されず、画像の濃度が低くなり、電子写真用被転写紙の取り扱い中に静電気を帯びて塵埃が付着し易く、また複写時にミスフィード、重送、放電マーク、トナー転写ヌケ等が発生し易くなる。
【００５２】
被転写層を前記表面電気抵抗に調整する等の目的で、前記被転写層に界面活性剤を含有させてもよい。界面活性剤としては、例えば、アルキルベンゼンイミダゾールスルホン酸塩、ナフタリンスルホン酸塩、カルボン酸スルホンエステル、リン酸エステル、ヘテロ環アミン類、アンモニウム塩類、ホスホニウム塩類及びベタイン系両性塩類、あるいはＺｎＯ、ＳｎＯ₂ 、Ａｌ₂ Ｏ₃ 、Ｉｎ₂ Ｏ₃ 、ＭｇＯ、ＢａＯ、ＭｏＯ₃ 等の金属酸化物が挙げられる。
【００５３】
［支持体］
本発明において、被転写層を支持体表面に形成する場合、支持体の基材としては、転写温度に耐えることができ、平滑性、白色度、滑り性、摩擦性、帯電防止性、転写後のへこみ等の点で要求を満足できるものならばどのようなものでも使用できる。例えば、上質紙、アート紙、コート紙、キャストコート紙、壁紙、裏打ち用紙、合成樹脂又はエマルジョン含浸紙、合成ゴムラテックス含浸紙、合成樹脂内添紙、板紙、セルロース繊維紙、ポリオレフィンコート紙（特に、ポリエチレンで両側を被覆した紙）等の紙支持体、また上記の任意の基材によって構成された層を組み合わせた積層体も使用できる。
【００５４】
本発明における支持体に使用される原紙は、写真印画紙に一般的に用いられる材料から選ばれる。即ち、針葉樹や広葉樹から選ばれる天然パルプや合成パルプを主原料に、必要に応じ、クレー、タルク、炭酸カルシウム、尿素樹脂微粒子等の填料、ロジン、アルキルケテンダイマー、高級脂肪酸、エポキシ化脂肪酸アミド、パラフィンワックス、アルケニルコハク酸等のサイズ剤、澱粉、ポリアミドポリアミンエピクロルヒドリン、ポリアクリルアミド等の紙力増強剤、硫酸バンド、カチオン性ポリマー等の定着剤等を添加したものが用いられる。
【００５５】
原紙の厚みは、５０〜２００μｍが好ましく、８０〜１７０μｍがより好ましい。厚みがこの範囲外になると、電子写真方式複写機やプリンターの中でジャミングしたり、手に持った感触に難が生じることがある。
原紙は平滑性及び平面性を付与する目的で、マシンカレンダー、スーパーカレンダー等の装置を用いて熱及び圧力を加えて表面処理することが好ましい。
原紙に被転写層を形成するに際しては、原紙表面に予め、グロー放電処理、コロナ放電処理、火炎処理、アンカーコート等の前処理をすることが被転写層と原紙との密着性を向上する観点から好ましい。
【００５６】
［その他の層］
本発明の電子写真用被転写紙に前記支持体を用いる場合には、支持体と被転写層との間に中間層を有していてもよい。
中間層により、クッション層、多孔層、被転写紙の剛度調節層等としての機能や、場合によっては接着層としての機能をもたせることができる。
また、支持体の被転写層が形成された面と反対側の面に、被転写紙の走行性を高めるためにバックコート層を設けてもよい。
【００５７】
本発明においては、前述した界面活性剤により所望の表面電気抵抗が得られない場合には、支持体と被転写層との間に導電性下塗層を設けてもよい。
前記導電性下塗層は導電性金属酸化物粒子が結合剤中に分散された層である。導電性金属酸化物粒子の材料としては、ＺｎＯ、ＴｉＯ、ＳｎＯ₂ 、Ａｌ₂ Ｏ₃ 、Ｉｎ₂ Ｏ₃ 、ＳｉＯ₂ 、ＭｇＯ、ＢａＯ及びＭｏＯ₃ が挙げられる。これらは、単独で使用してもよく、これらの複合酸化物を使用してもよい。また、金属酸化物は、異種元素を更に含有するものが好ましく、例えば、ＺｎＯに対してＡｌ、Ｉｎ等、ＴｉＯに対してＮｂ、Ｔａ等、ＳｎＯ₂ に対しては、Ｓｂ、Ｎｂ、ハロゲン元素等を含有（ドーピング）させたものが好ましい。これらの中で、ＳｂをドーピングしたＳｎＯ₂ が特に好ましい。また、導電性金属酸化物粒子の粒径は、０．２μｍ以下が好ましい。
【００５８】
前記導電性下塗層の結合剤の材料としては、ポリビニルアルコール、ポリアクリル酸、ポリアクリルアミド、ポリヒドロキシエチルアクリレート、ポリビニルピロリドン、水溶性ポリエステル、水溶性ポリウレタン、水溶性ナイロン、水溶性エポキシ樹脂、ゼラチン、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、カルボキシメチルセルロース及びこれらの誘導体等の水溶性ポリマー；水分散アクリル樹脂、水分散ポリエステル等の水分散型樹脂；アクリル樹脂エマルジョン、ポリ酢酸ビニルエマルジョン、ＳＢＲ（スチレン・ブタジエン・ゴム）エマルジョン等のエマルジョン；アクリル樹脂、ポリエステル樹脂等の有機溶剤可溶型樹脂が挙げられる。これらの内、水溶性ポリマー、水分散型樹脂及びエマルジョンが好ましい。これらのポリマーに、更に界面活性剤を添加してもよく、また架橋剤等を添加してもよい。
【００５９】
【実施例】
以下に、実施例を示し本発明を具体的に説明するが、本発明は以下の実施例のみに限定されるものではない。文中で特に断りのない限り、「部」は「重量部」を意味する。
【００６０】
（実施例１）
ポリエチレンテレフタレート７０部と、「ＳＴＡＦＩＸ Ｆ−ＬＣ」（富士写真フイルム（株）製）３０部とからなる樹脂組成物を、溶融押出し機により２９０℃に溶融し、Ｔダイスから吐出させ、火炎処理した厚さ１６０μｍの原紙に対して、ニップロールと冷却ロールとの間でニップしラミネートすることにより、図１に示すように、原紙１１の両面に被転写層１２ａ、１２ｂを形成した電子写真用被転写紙１０を作製した。
【００６１】
上記の被転写紙を作製する際、及び、作製した被転写紙について、以下の評価を行った。評価結果を表１に示す。
＜ラミネート適性の評価＞
一般的に知られるＰＥＴ溶融押出し温度である２９０℃で、Ｔダイスから押し出した時の溶融樹脂膜の安定性を、以下の基準により評価した。
○・・・安定している
△・・・膜耳部等に乱れがある
×・・・ラミネートができない
【００６２】
＜トナーの盛り上がり評価＞
はがきサイズの被転写紙の中央に、富士ゼロックス社製カラーレーザープリンター３３１０で黒色を出力プリントし、２×２ｃｍ角の面積で黒色印画したときに、黒色印画された部分と印画されていない部分の厚みの差（Δｈ）を測定し、以下の基準により評価した。
◎・・・Δｈが１μｍ未満
○・・・１μｍ以上〜２μｍ未満
△・・・２μｍ以上〜５μｍ未満
×・・・５μｍ以上
【００６３】
＜画像のザラつき評価＞
同様に黒色印画したときの斑点状の色ヌケ、色の濃淡、鮮鋭さを、以下の基準により目視にて評価した。
○・・・色ヌケ、濃淡差なし、かつ鮮鋭
△・・・色ヌケ、濃淡、鮮鋭性のいずれかが若干劣る
×・・・色ヌケ、濃淡、鮮鋭性のうち２つ以上が劣る
【００６４】
（実施例２）
実施例１における樹脂組成物を、ＰＥＴ６０部と「ＳＴＡＦＩＸ Ｆ−ＬＣ」３５部とからなる樹脂組成物９５部に酸化チタン粒子（ＫＡ−２０、チタン工業製）５部を添加した組成物に代え、原紙を厚さ１３０μｍの原紙に代え、図２に示すように、原紙２１の上面に被転写層２２を形成し、下面にＰＥＴ１００部からなる樹脂組成物を含むバックコート層２３を形成した以外は、実施例１と同様にして電子写真用被転写紙２０を作製し、実施例１と同様の評価を行った。評価結果を表１に示す。
【００６５】
（実施例３）
実施例１における樹脂組成物を、ＰＥＴ８５部と「ハイトレル４０５７」（東レ−Ｄｕｐｏｎｔ製）１５部とからなる樹脂組成物に代え、原紙を厚さ１３０μｍの原紙に代えた以外は、実施例１と同様にして電子写真用被転写紙を作製し、実施例１と同様の評価を行った。評価結果を表１に示す。
【００６６】
（実施例４）
実施例１における樹脂組成物を、ＰＥＴ９０部と「グリラックスＥ１２０」（大日本インキ化学工業製）１０部とからなる樹脂組成物に代え、原紙を厚さ１２５μｍの原紙に代え、図２に示すように、原紙２１の上面に被転写層２２を形成し、下面にＰＥＴ１００部からなる樹脂組成物を含むバックコート層２３を形成した以外は、実施例１と同様にして電子写真用被転写紙２０を作製し、実施例１と同様の評価を行った。評価結果を表１に示す。
【００６７】
（比較例１）
実施例１における樹脂組成物を、ＰＥＴ１００部からなる樹脂組成物に代えた以外は、実施例１と同様にして電子写真用被転写紙を作製し、実施例１と同様の評価を行った。評価結果を表１に示す。
【００６８】
（比較例２）
実施例１における樹脂組成物を、ＰＥＴ４０部と「ＳＴＡＦＩＸ Ｆ−ＬＣ」６０部とからなる樹脂組成物に代え、原紙を厚さ１３０μｍの原紙に代え、図２に示すように、原紙２１の上面に被転写層２２を形成し、下面にＰＥＴ１００部からなる樹脂組成物を含むバックコート層２３を形成した以外は、実施例１と同様にして電子写真用被転写紙２０を作製し、実施例１と同様の評価を行った。評価結果を表１に示す。
【００６９】
（比較例３）
実施例１における樹脂組成物を、ＰＥＴ６０部と脂肪族ポリエステル（ポリサイザーＷ３６０、大日本インキ化学工業製）４０部とからなる樹脂組成物に代え、原紙を厚さ１３０μｍの原紙に代え、図２に示すように、原紙２１の上面に被転写層２２を形成しようとしたが、樹脂の熱適性が悪いため、均一な被転写層を形成することができなかった。
【００７０】
（比較例４）
実施例１における樹脂組成物を、ＰＥＴ８５部とポリプロピレン１５部とからなる樹脂組成物に代え、原紙を厚さ１２５μｍの原紙に代え、図２に示すように、原紙２１の上面に被転写層２２を形成し、下面にＰＥＴ１００部からなる樹脂組成物を含むバックコート層２３を形成した以外は、実施例１と同様にして電子写真用被転写紙２０を作製し、実施例１と同様の評価を行った。評価結果を表１に示す。
【００７１】
【表１】

【００７２】
表１の結果から、本発明の電子写真用被転写紙である実施例１〜４は、ラミネート適性、トナーの盛り上がり、画像のザラつきのいずれについても、優れていることがわかる。一方、ＰＥＴ以外の芳香族ポリエステル樹脂を含んでいない被転写層を有する比較例１では、トナーの盛り上がりが生じている。これに対し、ＰＥＴ以外の芳香族ポリエステル樹脂を多量に含んだ被転写層を有する比較例２では、画像のザラつきが生じている。また、脂肪族ポリエステル樹脂を含んだ被転写層を有する比較例３では、熱適性が悪いため、ラミネートができなかった。また、ポリプロピレンを含んだ被転写層を有する比較例４では、トナーの盛り上がりが生じ、画像形成が不良であった。
【００７３】
【発明の効果】
本発明によると、印画時のトナー像の凹凸が十分に小さく、鮮明な画像が得られる電子写真用被転写紙を提供することができる。
【００７４】
【図面の簡単な説明】
【図１】本発明の電子写真用被転写紙の基本構成の一例を示す断面の模式図である。
【図２】本発明の電子写真用被転写紙の基本構成の他の一例を示す断面の模式図である。
【００７５】
【符号の説明】
１０、２０ 電子写真用被転写紙
１１、２１ 原紙
１２ａ、１２ｂ、２２ 被転写層
２３ バックコート層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transfer paper for electrophotography in which a color toner image has small unevenness during printing and a clear image can be obtained.
[0002]
[Prior art]
In electrophotography, toner is electrostatically deposited on a transfer paper, and is heated and pressed with a heat roll or the like to fix it, thereby forming an image. At this time, a slight convex portion is formed on the transfer paper due to the melted toner. In the case of a color image, toners of three colors of yellow, magenta, and cyan are laminated particularly in the black portion, and the toner swells conspicuously, which causes a decrease in image sharpness and surface gloss.
[0003]
For the purpose of alleviating the influence of the unevenness of the toner at the time of printing, for example, JP-A-59-184361 discloses spraying and applying lacquer or the like on the image surface to form a glossy film on the surface. Japanese Patent Application Laid-Open No. 5-88400 discloses that a transparent resin layer having an apparent melt viscosity lower than that of the toner binder resin is provided on the upper portion at the toner fixing temperature, and the toner is sunk in the transparent resin layer. Each technique is disclosed. However, in the former method, since the lacquer containing the solvent is sprayed, there is a risk that the sharpness of the image may be reduced or color unevenness may occur due to the influence of the solvent. In the latter case, the surface layer having a low melting temperature is peeled off. This is likely to cause image destruction. In order to solve these problems, various attempts have been made. However, an electrophotographic transfer paper that provides a clear image with a small unevenness of the toner image at the time of printing has not yet been obtained. Currently.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrophotographic transfer paper that can solve the above-described conventional problems, sufficiently reduce the unevenness of a toner image during printing, and obtain a clear image.
[0005]
[Means for Solving the Problems]
As a result of intensive studies on the electrophotographic transfer paper, the present inventors have found that the electrophotographic transfer paper having a transfer layer containing a specific aromatic polyester resin on the support is a color toner image at the time of printing. The present inventors have found that unevenness, that is, toner swell can be improved, and have reached the present invention. That is, the present invention
<1> An electrophotographic transfer paper having a transfer layer on at least one surface of a support, the transfer layer comprising 95 to 55 parts by weight of polyethylene terephthalate and an aromatic polyester other than the polyethylene terephthalate An electrophotographic transfer paper formed by melt-extruding a resin composition containing 5 to 45 parts by weight of a resin onto the support.
<2> The electrophotographic transfer paper according to <1>, wherein the aromatic polyester resin has a terephthalic acid unit, an ethylene glycol unit, a triethylene glycol unit, and an ethylene oxide adduct unit of bisphenol A.
<3> The electrophotographic transfer paper according to <1>, wherein the aromatic polyester resin has a terephthalic acid unit, a tetramethylene glycol unit, and a polytetramethylene glycol unit.
<4> The electrophotographic transfer paper according to any one of <1> to <3>, wherein the transfer layer further contains an inorganic pigment.
In the present invention, by adding a specific aromatic polyester resin as a soft component to the polyethylene terephthalate constituting the transfer layer, the film quality of the transfer layer is softened and the toner is more likely to sink, Smoothing can be achieved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The electrophotographic transfer paper of the present invention comprises a transfer layer having a specific configuration on a support, but other layers may be formed as necessary.
[0007]
[Transfer layer]
The transfer layer contains a resin composition containing polyethylene terephthalate and other aromatic polyester resin, but an embodiment containing an inorganic pigment is preferable, and if necessary, further contains other components. It becomes.
[0008]
(polyethylene terephthalate)
Polyethylene terephthalate (hereinafter sometimes referred to as “PET”) is a main component constituting the transfer layer, and the mixing ratio with respect to the aromatic polyester resin other than the PET is 95 to 55 parts by weight of the PET component. Yes, preferably 90-60 parts by weight, more preferably 85-60 parts by weight. If the added amount of the PET component is more than 95 parts by weight, the effect of reducing the unevenness of the toner image may be insufficient. On the other hand, when the addition amount of the PET component is less than 55 parts by weight, the stability of the laminate film is deteriorated and the suitability for lamination may be deteriorated due to a phenomenon such as neck-in.
The PET preferably has an IV value (intrinsic viscosity) of 0.5 to 0.8 with respect to the melt laminate.
The PET used in the present invention can be synthesized by a conventionally known method.
[0009]
(Aromatic polyester resin)
As described above, in the present invention, from the viewpoint of softening the film quality of the transferred layer, facilitating the penetration of the toner at the time of printing, and absorbing the swelled portion of the toner, it is a soft component for the PET constituting the transferred layer. As an aromatic polyester resin other than PET. Since the aromatic polyester resin is excellent in heat resistance, the suitability for laminating is hardly deteriorated as in the case where an aliphatic polyester resin having poor heat resistance is mixed with PET and melt-extruded. Although a small amount of polyolefin resin may be added as a soft component, it is in a phase-separated state with PET, that is, a “sea-island structure”, and the effect of uniformly softening the very surface of the transferred layer is small. There is no solution to the excitement.
[0010]
The mixing ratio of the aromatic polyester resin to PET is 5 to 45 parts by weight of the aromatic polyester resin, preferably 10 to 40 parts by weight, and more preferably 15 to 40 parts by weight. If the amount of the aromatic polyester resin added is less than 5 parts by weight, the effect of reducing the unevenness of the toner image may be insufficient. On the other hand, if the amount of the aromatic polyester resin added is more than 45 parts by weight, the stability of the laminate film may be deteriorated or the toner image may be poorly fixed.
[0011]
The aromatic polyester resin preferably has a terephthalic acid unit, an ethylene glycol unit, a triethylene glycol unit, and an ethylene oxide adduct unit of bisphenol A. Specifically, the aromatic polyester resin is a dihydric alcohol containing a repeating unit of an aromatic dibasic acid component containing a terephthalic acid unit, and an ethylene oxide adduct unit of ethylene glycol unit, triethylene glycol unit, and bisphenol A. It preferably has a repeating unit of components.
[0012]
The aromatic polyester resin preferably has a terephthalic acid unit, a tetramethylene glycol unit, and a polytetramethylene glycol unit. Specifically, the aromatic polyester resin has a repeating unit of an aromatic dibasic acid component containing a terephthalic acid unit, and a repeating unit of a dihydric alcohol component containing a tetramethylene glycol unit and a polytetramethylene glycol unit. It is preferable.
[0013]
As the repeating unit of the aromatic dibasic acid component, a terephthalic acid unit is particularly preferably used. In addition, an isophthalic acid unit, a 2,6-naphthalenedicarboxylic acid unit, a sulfobenzenedicarboxylic acid unit, and the like are preferably used. . These may be used alone or in combination of two or more.
[0014]
The total of the repeating units of the aromatic dibasic acid component occupies at least 80 mol%, preferably 90 mol% or more, and most preferably 100 mol% of the total repeating units of all dibasic acid components. As other dibasic acid components, aromatic dicarboxylic acids such as phthalic acid and 2,7-naphthalenedicarboxylic acid; adipic acid, malonic acid, succinic acid, azelaic acid, sebacic acid, etc. Aliphatic dicarboxylic acids; cycloaliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be used. A polybasic acid component such as trimellitic acid may also be used.
[0015]
Further, as the repeating unit of the dihydric alcohol component, ethylene glycol unit, triethylene glycol unit, tetramethylene glycol unit, polytetramethylene glycol unit, ethylene oxide adduct unit of bisphenol A are particularly preferably used. Also, diethylene glycol units, tetraethylene glycol units and the like are preferably used. These may be used alone or in combination of two or more.
Among these, when a bisphenol A unit or a derivative unit thereof is added, the crystallinity of the aromatic polyester resin can be suppressed, and the embedding of the toner in the transfer layer can be improved.
[0016]
The total of the repeating units of the dihydric alcohol component occupies at least 70 mol% or more of the total of the repeating units of all the polyhydric alcohol components, preferably 80 mol% or more, and preferably 90 mol% or more. More preferred is 100 mol%.
As a polyhydric alcohol component other than the above, 1,4-butanediol, 1,6-hexanediol, 1,3-propanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, as long as the characteristics are not impaired. 1,2-propylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, diethylene glycol, polyethylene glycol and the like can be used.
[0017]
In particular, the aromatic polyester resin preferably contains 1 to 55 mol% of an ethylene oxide adduct unit of bisphenol A as a dihydric alcohol component.
[0018]
Since the aromatic polyester resin softens moderately at the toner fixing temperature, the toner is embedded in the transferred layer, and generally the inclination angle at the fixing temperature between the surface of the transferred layer and the toner is reduced, so that the unevenness is reduced. Almost no fixed image can be obtained. Hereinafter, the aromatic polyester resin preferably used in the present invention will be described in detail.
The aromatic polyester resin includes the following (a):
[0019]
[Chemical 1]

[0020]
A repeating unit of an aromatic dibasic acid component containing a terephthalic acid unit represented by: and (b) below:
[0021]
[Chemical 2]

[0022]
An ethylene glycol unit represented by the following (c):
[0023]
[Chemical 3]

[0024]
And a triethylene glycol unit represented by the following (d):
[0025]
[Formula 4]

[0026]
(However, n represents 1-5.) It is preferable to have the repeating unit of the bihydric alcohol component containing the ethylene oxide adduct unit of bisphenol A represented by these.
As such an aromatic polyester resin, for example, “STAFIX F-LC” (produced by Fuji Photo Film Co., Ltd.) represented by the following formula is preferably exemplified.
[0027]
[Chemical formula 5]

[0028]
The aromatic polyester resin is the following (e):
[0029]
[Chemical 6]

[0030]
A repeating unit of an aromatic dibasic acid component containing a terephthalic acid unit represented by the formula (f):
[0031]
[Chemical 7]

[0032]
A tetramethylene glycol unit represented by: and the following (g):
[0033]
[Chemical 8]

[0034]
It is preferable to have the repeating unit of the dihydric alcohol component containing the polytetramethylene glycol unit represented by these.
Preferred examples of such an aromatic polyester resin include “Hytrel” (manufactured by Toray-Dupont), “Grease” (manufactured by Dainippon Ink & Chemicals), “Perprene” (manufactured by Toyobo), and the like.
[0035]
The above aromatic polyester resin is obtained by esterifying or transesterifying a dibasic acid and a dihydric alcohol in the same manner as in the synthesis of ordinary polyethylene terephthalate or polyethylene-2,6-naphthalate, and then vacuum. It can be synthesized by performing a polycondensation reaction below. It can also be obtained by a polyester depolymerization method as described in JP-B-53-37920. In addition, as the dibasic acid, an ester exchange reaction is performed using at least one of alkyl esters of dicarboxylic acid such as dimethyl terephthalate, dimethyl isophthalate, dimethyl-2,6-naphthalene carboxylate, and then a polycondensation reaction is performed. Alternatively, direct esterification using a dicarboxylic acid, followed by a polycondensation reaction may be performed.
[0036]
For example, a dibasic acid and a dihydric alcohol are reacted at 180 to 280 ° C. under atmospheric pressure for 120 to 240 minutes, and the distillation of water or alcohol is terminated to complete the transesterification reaction. Next, the pressure in the reaction system is set to a high vacuum of 1 mmHg or less, and the temperature is raised to 240 to 290 ° C. and heated at this temperature for 60 to 180 minutes to obtain an aromatic polyester resin.
[0037]
The number average molecular weight of the aromatic polyester resin is preferably in the range of 1500 to 5000. The weight average molecular weight of the aromatic polyester resin is preferably in the range of 2500 to 15000. The aromatic polyester resin preferably has a weight average molecular weight / number average molecular weight in the range of 1.2 to 3.0.
[0038]
(Inorganic pigment)
In the present invention, it is preferable to add an inorganic pigment to the transfer layer for the purpose of improving the whiteness and sharpening the image.
Examples of the inorganic pigment include titanium oxide, barium sulfate, zinc oxide, talc, calcium carbonate, aluminum oxide, and silicon oxide powders, solid solutions thereof, and blue or violet such as ultramarine. System pigments can also be used. The particle diameter of the inorganic pigment is about 0.04 to 1 μm. When the particle diameter is smaller than 0.04 μm, it is difficult to uniformly disperse the inorganic pigment in the resin, which is not preferable. On the other hand, if the particle diameter is larger than 1 μm, the surface of the coating film of the composition becomes too rough and the image quality is deteriorated.
Moreover, 1-30 weight% is preferable with respect to the said resin composition, and, as for the addition amount of an inorganic pigment, 3-10 weight% is more preferable. If the addition amount is less than 1% by weight, the effect of improving the whiteness may be poor. On the other hand, if the addition amount is more than 30% by weight, the stability of the laminate film may be poor.
Among these inorganic pigments, titanium oxide and barium sulfate are preferable from the viewpoint of whiteness, and a preferable average particle diameter is 0.1 to 0.8 μm. Specific trade names of the inorganic pigments used include KA-10 and KA-20 manufactured by Titanium Industry.
[0039]
(Other ingredients)
As long as the effects of the present invention are not impaired, other components can be added to the transferred layer for the purpose of controlling the characteristics of the layer.
In addition to the polyethylene terephthalate and the aromatic polyester resin, the resin composition constituting the transferred layer may contain other polymer in the range of 20% by weight or less of the total components of the transferred layer. As the polymer used in combination, one having a glass transition temperature of 60 ° C. or higher (preferably 60 to 120 ° C.) is generally used. For example, polyester resins other than the above, polyether resins, acrylic resins, epoxy resins, urethane resins, amino resins, phenol resins and the like can be mentioned.
[0040]
The transfer layer can contain a filler, a matting agent, a fluorescent brightening agent, a release agent, an anti-fading agent, and the like as other components.
The filler can be added for the purpose of adjusting the friction coefficient. Examples of the filler include silica, alumina, calcium carbonate and the like.
The method for adding these pigments and fillers to the resin composition for forming the transfer layer is not particularly limited. For example, a method of adding the pigment or filler directly into the extruder when the resin is melt-extruded, a master in advance. A known suitable method such as a method of preparing a pellet and adding it can be applied.
[0041]
Since the addition of the matting agent can improve the slipperiness, it has a good effect on the wear resistance and scratch resistance. Materials used for the matting agent include fluorine resins, low molecular weight polyolefin organic polymers (for example, polyethylene matting agents, paraffinic or microcrystalline wax emulsions), and materials used for substantially spherical matting agents. Bead-like plastic powders (material examples, cross-linked PMMA, polycarbonate, polyethylene terephthalate, polyethylene or polystyrene), and inorganic fine particles (for example, SiO ₂ , Al ₂ O _Three , Talc or kaolin). The content of the matting agent is preferably 0.1 to 10% by weight with respect to the resin composition.
[0042]
Examples of the optical brightener include K.I. Examples thereof include compounds described in “The Chemistry of Synthetic Dies”, Volume V, Chapter 8, JP-A-61-143752, etc., edited by Veenkataraman.
Specific examples include stilbene compounds, coumarin compounds, biphenyl compounds, benzoxazolyl compounds, naphthalimide compounds, pyrazoline compounds, carbostyryl compounds, 2,5-dibenzoxazole thiophene compounds, and the like. It is done. The optical brightener can be used in combination with an anti-fading agent.
[0043]
Examples of the mold release agent include solid wax such as polyethylene wax, amide wax, fine powder of silicon resin, fine powder of fluorine resin: surfactants such as fluorine and phosphate esters: paraffin, Conventionally known release agents such as silicone-based and fluorine-based oils can be used.
[0044]
As the anti-fading agent, for example, an antioxidant, an ultraviolet absorber, or a certain metal complex can be used.
Examples of the antioxidant include a coumarone compound, a coumaran compound, a phenol compound (for example, a hindered phenol), a hydroquinone derivative, a hindered amine derivative, and a spiroindane compound. In addition, compounds described in JP-A No. 61-159644 are also effective.
[0045]
Examples of ultraviolet absorbers include benzotriazole compounds (described in US Pat. No. 3,533,794), 4-thiazolidone compounds (described in US Pat. No. 3,352,681, etc.), benzophenone compounds (Japanese Patent Laid-Open No. 56-2784). And other compounds described in JP-A-54-48535, JP-A-62-136641, JP-A-61-88256, and the like. Further, an ultraviolet absorbing polymer described in JP-A-62-260152 is also effective.
[0046]
As the metal complexes, U.S. Pat. Nos. 4,241,155, 4,245,018 (columns 3-36), 4,254,195 (columns 3-8), JP-A-62-174741, 61-88256 (27th). -29 pages), JP-A-1-75568, JP-A-63-199248, and the like.
[0047]
Specific examples of useful antifading agents are described in JP-A-62-215272 (pages 125 to 137).
The anti-fading agent contained in the transfer layer is preferably an inorganic fine powder. Specifically, it is a fine powder such as titanium oxide or zinc oxide, and the preferred particle size is about 600 nm. The content of these fine powders is preferably from 0.1 to 50% by weight, more preferably from 0.1 to 20% by weight, based on the total amount of the transferred layer forming component.
Each of the antioxidant, ultraviolet absorber, and metal complex used as the anti-fading agent may be used alone or in combination of two or more. You may use combining these different anti-fading prevention.
[0048]
Various surfactants can be used for the layer to be transferred as a coating aid or for the purpose of improving peelability, improving slipperiness, preventing static charge and the like.
As the surfactant, any of a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, and a cationic surfactant can be used. Specific examples of these are described in JP-A Nos. 62-173463 and 62-183457.
[0049]
(Melt extrusion method, etc.)
The transfer layer in the electrophotographic transfer paper of the present invention is formed by a melt extrusion method. In the melt extrusion method, a molten resin film extruded through a wide slit die (so-called T-die) from a heated extruder is brought into contact with a support and continuously pressed with a roller, or similarly melted. The general method etc. which extrude resin on a cooling roll, wind up, and make into a film are mentioned. According to the melt extrusion method, a uniform film made of the resin composition can be easily formed on a support.
The extruder used for forming the transfer layer by the melt extrusion method may be uniaxial or biaxial, and has an ability to uniformly mix the polyethylene terephthalate and the aromatic polyester resin. It is important to be.
[0050]
The transfer layer can be formed on one surface or both surfaces of the support.
The layer thickness of the transferred layer is preferably in the range of 20 to 45 μm, more preferably in the range of 23 to 35 μm. When the layer thickness is less than 20 μm, adhesion to the support may be deteriorated and toner embedding may be deteriorated. On the other hand, if the layer thickness is thicker than 45 μm, the rigidity becomes too high, and for example, jamming may occur when passing through a printer.
[0051]
The transferred layer is 1 × 10 ⁹ ~ 1x10 ¹³ It is preferable to have a surface electrical resistance in the range of Ω (under conditions of 25 ° C. and 65% RH). 1 × 10 ⁹ If it is less than Ω, the toner amount when the toner is transferred to the transfer layer of the electrophotographic transfer paper is not sufficient, and the density of the resulting toner image may be low. Meanwhile, 1 × 10 ¹³ If it exceeds Ω, more than necessary charge is generated at the time of transfer, the toner is not sufficiently transferred, the density of the image becomes low, and dust is easily attached due to static electricity during handling of the electrophotographic transfer paper, Misfeeds, double feeds, discharge marks, toner transfer leakage, etc. are likely to occur during copying.
[0052]
For the purpose of adjusting the transfer layer to the surface electric resistance, a surfactant may be contained in the transfer layer. Examples of the surfactant include alkylbenzene imidazole sulfonate, naphthalene sulfonate, carboxylic acid sulfone ester, phosphate ester, heterocyclic amines, ammonium salts, phosphonium salts and betaine amphoteric salts, or ZnO, SnO. ₂ , Al ₂ O _Three , In ₂ O _Three , MgO, BaO, MoO _Three And metal oxides such as
[0053]
[Support]
In the present invention, when the layer to be transferred is formed on the surface of the support, the substrate of the support can withstand the transfer temperature, smoothness, whiteness, slipperiness, friction, antistatic properties, after transfer Any material can be used as long as it satisfies the requirements in terms of dents. For example, fine paper, art paper, coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, polyolefin coated paper (especially A paper support such as paper coated on both sides with polyethylene) or a laminate obtained by combining layers composed of any of the above-mentioned substrates can also be used.
[0054]
The base paper used for the support in the present invention is selected from materials generally used for photographic printing paper. That is, natural pulp and synthetic pulp selected from conifers and hardwoods as the main raw material, clay, talc, calcium carbonate, urea resin fine particle filler, rosin, alkyl ketene dimer, higher fatty acid, epoxidized fatty acid amide, if necessary A sizing agent such as paraffin wax and alkenyl succinic acid, a paper strength enhancer such as starch, polyamide polyamine epichlorohydrin and polyacrylamide, a fixing agent such as a sulfuric acid band and a cationic polymer, and the like are used.
[0055]
The thickness of the base paper is preferably 50 to 200 μm, more preferably 80 to 170 μm. If the thickness is out of this range, jamming may occur in an electrophotographic copying machine or printer, or the touch feeling may be difficult.
For the purpose of imparting smoothness and flatness, the base paper is preferably surface-treated by applying heat and pressure using an apparatus such as a machine calendar or a super calendar.
When forming the transfer layer on the base paper, pretreatment such as glow discharge treatment, corona discharge treatment, flame treatment, anchor coating, etc. on the surface of the base paper in advance improves the adhesion between the transfer layer and the base paper. To preferred.
[0056]
[Other layers]
When the support is used for the electrophotographic transfer paper of the present invention, an intermediate layer may be provided between the support and the transfer layer.
The intermediate layer can provide a function as a cushion layer, a porous layer, a stiffness adjusting layer of the transfer paper, or a function as an adhesive layer in some cases.
In addition, a backcoat layer may be provided on the surface of the support opposite to the surface on which the transfer layer is formed in order to improve the runnability of the transfer paper.
[0057]
In the present invention, when a desired surface electric resistance cannot be obtained by the above-described surfactant, a conductive undercoat layer may be provided between the support and the transferred layer.
The conductive undercoat layer is a layer in which conductive metal oxide particles are dispersed in a binder. As a material of the conductive metal oxide particles, ZnO, TiO, SnO ₂ , Al ₂ O _Three , In ₂ O _Three , SiO ₂ , MgO, BaO and MoO _Three Is mentioned. These may be used alone or in combination. The metal oxide preferably further contains a different element, for example, Al, In, etc. with respect to ZnO, Nb, Ta, etc. with respect to TiO, SnO, etc. ₂ Is preferable to contain (doping) Sb, Nb, a halogen element or the like. Among these, SnO doped SnO ₂ Is particularly preferred. The particle size of the conductive metal oxide particles is preferably 0.2 μm or less.
[0058]
As the binder material for the conductive undercoat layer, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyhydroxyethyl acrylate, polyvinyl pyrrolidone, water-soluble polyester, water-soluble polyurethane, water-soluble nylon, water-soluble epoxy resin, gelatin Water-soluble polymers such as hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and derivatives thereof; water-dispersed resins such as water-dispersed acrylic resins and water-dispersed polyesters; acrylic resin emulsions, polyvinyl acetate emulsions, SBR (styrene-butadiene- Rubber) Emulsions such as emulsions; organic solvent soluble resins such as acrylic resins and polyester resins. Of these, water-soluble polymers, water-dispersed resins and emulsions are preferred. A surfactant may be further added to these polymers, and a crosslinking agent or the like may be added.
[0059]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited only to the following examples. Unless otherwise specified in the text, “part” means “part by weight”.
[0060]
Example 1
A resin composition comprising 70 parts of polyethylene terephthalate and 30 parts of “STAFIX F-LC” (manufactured by Fuji Photo Film Co., Ltd.) was melted at 290 ° C. by a melt extruder, discharged from a T-die, and flame-treated. A base sheet having a thickness of 160 μm is nipped between a nip roll and a cooling roll and laminated to form a transfer layer for electrophotography 12a and 12b formed on both sides of the base paper 11 as shown in FIG. Paper 10 was produced.
[0061]
The following evaluation was performed when producing the above-mentioned transfer paper and for the produced transfer paper. The evaluation results are shown in Table 1.
<Evaluation of laminate suitability>
The stability of the molten resin film when extruded from a T-die at a commonly known PET melt extrusion temperature of 290 ° C. was evaluated according to the following criteria.
○ ・ ・ ・ Stable
Δ: Disturbance in membrane ear
× ・ ・ ・ Cannot be laminated
[0062]
<Evaluation of toner swell>
In the center of a postcard-sized transfer paper, when black is printed out with a color laser printer 3310 manufactured by Fuji Xerox Co., Ltd., and printed black with an area of 2 x 2 cm square, the black printed part and the non-printed part The thickness difference (Δh) was measured and evaluated according to the following criteria.
◎ ・ ・ ・ Δh is less than 1μm
○ ・ ・ ・ 1μm to less than 2μm
Δ: 2 μm or more and less than 5 μm
× ・ ・ ・ 5μm or more
[0063]
<Rough image evaluation>
Similarly, spot-like color leakage, color shading, and sharpness when printed black were visually evaluated according to the following criteria.
○ ... Colored, no contrast, and sharp
Δ: Slightly inferior in color, darkness, or sharpness
X: Two or more of color leakage, shading and sharpness are inferior
[0064]
(Example 2)
The resin composition in Example 1 was replaced with a composition in which 5 parts of titanium oxide particles (KA-20, manufactured by Titanium Industry) were added to 95 parts of a resin composition composed of 60 parts of PET and 35 parts of “STAFIX F-LC”. 2 except that the base paper is replaced with a base paper having a thickness of 130 μm, and a transfer layer 22 is formed on the upper surface of the base paper 21 and a backcoat layer 23 containing a resin composition consisting of 100 parts of PET is formed on the lower surface as shown in FIG. Produced the electrophotographic transfer paper 20 in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0065]
Example 3
Example 1 except that the resin composition in Example 1 was replaced with a resin composition consisting of 85 parts of PET and 15 parts of “Hytrel 4057” (manufactured by Toray-Dupont), and the base paper was replaced with a base paper having a thickness of 130 μm. Similarly, electrophotographic transfer paper was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0066]
(Example 4)
The resin composition in Example 1 is replaced with a resin composition consisting of 90 parts of PET and 10 parts of “Glare E120” (Dainippon Ink Chemical Co., Ltd.), and the base paper is replaced with a 125 μm-thick base paper, as shown in FIG. Thus, a transfer paper for electrophotography was formed in the same manner as in Example 1 except that the transfer layer 22 was formed on the upper surface of the base paper 21 and the back coat layer 23 containing a resin composition consisting of 100 parts of PET was formed on the lower surface. 20 was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0067]
(Comparative Example 1)
An electrophotographic transfer paper was prepared in the same manner as in Example 1 except that the resin composition in Example 1 was replaced with a resin composition consisting of 100 parts of PET, and the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
[0068]
(Comparative Example 2)
The resin composition in Example 1 is replaced with a resin composition composed of 40 parts of PET and 60 parts of “STAFIX F-LC”, and the base paper is replaced with a base paper having a thickness of 130 μm, and as shown in FIG. An electrophotographic transfer paper 20 was prepared in the same manner as in Example 1 except that the transfer layer 22 was formed on the lower surface and the back coat layer 23 containing a resin composition consisting of 100 parts of PET was formed on the lower surface. Evaluation similar to 1 was performed. The evaluation results are shown in Table 1.
[0069]
(Comparative Example 3)
The resin composition in Example 1 was replaced with a resin composition comprising 60 parts of PET and 40 parts of aliphatic polyester (Polysizer W360, manufactured by Dainippon Ink and Chemicals), and the base paper was replaced with a base paper having a thickness of 130 μm, and FIG. As shown, an attempt was made to form the transferred layer 22 on the upper surface of the base paper 21, but a uniform transferred layer could not be formed due to the poor thermal suitability of the resin.
[0070]
(Comparative Example 4)
The resin composition in Example 1 is replaced with a resin composition comprising 85 parts of PET and 15 parts of polypropylene, the base paper is replaced with a base paper having a thickness of 125 μm, and the transfer layer 22 is formed on the upper surface of the base paper 21 as shown in FIG. The electrophotographic transfer paper 20 was prepared in the same manner as in Example 1 except that the back coat layer 23 containing a resin composition consisting of 100 parts of PET was formed on the lower surface, and the same evaluation as in Example 1 was made. Went. The evaluation results are shown in Table 1.
[0071]
[Table 1]

[0072]
From the results in Table 1, it can be seen that Examples 1 to 4, which are electrophotographic transfer papers of the present invention, are excellent in all of laminating suitability, toner swell and image roughness. On the other hand, in Comparative Example 1 having a transfer layer that does not contain an aromatic polyester resin other than PET, toner swells. On the other hand, in Comparative Example 2 having a transferred layer containing a large amount of an aromatic polyester resin other than PET, image roughness occurs. In Comparative Example 3 having a transfer layer containing an aliphatic polyester resin, lamination was not possible due to poor thermal suitability. In Comparative Example 4 having a transfer layer containing polypropylene, toner swelled and image formation was poor.
[0073]
【The invention's effect】
According to the present invention, it is possible to provide a transfer sheet for electrophotography in which unevenness of a toner image during printing is sufficiently small and a clear image can be obtained.
[0074]
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of the basic configuration of an electrophotographic transfer paper of the present invention.
FIG. 2 is a schematic cross-sectional view showing another example of the basic configuration of the electrophotographic transfer paper of the present invention.
[0075]
[Explanation of symbols]
10, 20 Electrophotographic transfer paper
11, 21 Base paper
12a, 12b, 22 Transfer target layer
23 Backcoat layer

Claims (4)

An electrophotographic transfer paper having a transfer layer on at least one surface of a support, wherein the transfer layer comprises 95 to 55 parts by weight of polyethylene terephthalate and an aromatic polyester resin other than polyethylene terephthalate. An electrophotographic transfer paper, which is formed by melt-extruding a resin composition containing ˜45 parts by weight on a support. 2. The electrophotographic transfer paper according to claim 1, wherein the aromatic polyester resin has a terephthalic acid unit, an ethylene glycol unit, a triethylene glycol unit, and an ethylene oxide adduct unit of bisphenol A. The electrophotographic transfer paper according to claim 1, wherein the aromatic polyester resin has a terephthalic acid unit, a tetramethylene glycol unit, and a polytetramethylene glycol unit. The electrophotographic transfer paper according to claim 1, wherein the transfer layer further contains an inorganic pigment.

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