JP2004109647A - Image-receiving sheet for electrophotography and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image-receiving sheet for electrophotography which enables formation of an image having excellent glossiness in particular and suppresses the planar deterioration due to humidity change. <P>SOLUTION: In the image-receiving sheet for electrophotography, the image-receiving layer comprising a lamination constitution of two layers or more is disposed on a substrate and, in the image-receiving layer, the hardness on the nearest layer to the substrate is higher than the hardness on the other layers. In addition, it is preferable that the melt viscosity of the resin included in the layer nearest to the substrate at the fixing temperature is larger than the melt viscosity of the resin included in the other layers at the fixing temperature and the fixing temperature gets into the range of 90∼120°C. <P>COPYRIGHT: (C)2004,JPO

Description

【０１０７】
本発明の受像層は、前記支持体上に、受像層に用いられるポリマーを含有する塗工液をワイヤーコーター等で塗布し、乾燥することによって設けられる。塗工液は、例えば、熱可塑性ポリマー、可塑剤等の添加剤を、アルコール及びケトン等の有機溶剤に溶解し、或いは均一に分散して調製される。ここで使用される有機溶剤としては、例えば、メタノール、イソプロピルアルコール及びメチルエチルケトン等が挙げられる。受像層に用いるポリマーが水溶性であれば、上記支持体上にポリマー水溶液を塗布することによって受像層を調製できる。また、水溶性でないポリマーについては、水分散液で支持体上に塗布することも可能である。
本発明で使用される前記ポリマーの成膜温度は、プリント前の保存に対しては、室温以上が好ましく、トナー粒子の定着に対しては１００℃以下が好ましい。
【０１０８】
本発明の受像層は、乾燥後の塗布質量が、例えば、１〜２０ｇ／ｍ^２、好ましくは、４〜１５ｇ／ｍ^２になるように塗布される。また、受像層の厚みは、例えば、１〜２０μｍ、好ましくは、４〜１５μｍの範囲にあることが適当である。前記受像層の厚みとしては、特に制限はないが、１〜３０μｍが好ましく、２〜２０μｍがより好ましい。
【０１０９】
〔受像層の諸物性〕
前記受像層は、白色度が高いのが好ましい。該白色度としては、ＪＩＳ　Ｐ　８１２３に規定される方法で測定して、８５％以上が好ましい。また、４４０ｎｍ〜６４０ｎｍの波長域で、分光反射率が８５％以上、かつ同波長域の最大分光反射率と最低分光反射率の差が５％以内が好ましい。更には、４００ｎｍ〜７００ｎｍの波長域で分光反射率が８５％以上、かつ同波長域の最大分光反射率と最低分光反射率の差が５％以内がより好ましい。
また、前記白色度としては、具体的には、ＣＩＥ　１９７６（Ｌ^＊ａ^＊ｂ^＊）色空間において、Ｌ^＊値が８０以上であるのが好ましく、８５以上であるのが好ましく、９０以上であるのがより好ましい。また、白色の色味はできるだけニュートラルであるのが好ましい。白色色味としては、Ｌ^＊ａ^＊ｂ^＊空間において、（ａ^＊）^２＋（ｂ^＊）^２の値が５０以下であるのが好ましく、１８以下であるのがより好ましく、５以下であるのが更に好ましい。
【０１１０】
前記受像層としては、光沢性が高いのが好ましい。光沢度としては、トナーが無い白色から最大濃度の黒色までの全領域において、４５度光沢度が６０以上であるのが好ましく、７５以上であるのがより好ましく、９０以上であるのが更に好ましい。
但し、光沢度は１１０以下であることが好ましい。１１０を超えると金属光沢のようになり画質として好ましくない。
尚、前記光沢度は、ＪＩＳ　Ｚ　８７４１に基づいて測定することができる。
【０１１１】
前記受像層は、平滑性が高いのが好ましい。該平滑度としては、トナーが無い白色から最大濃度の黒色までの全領域において、算術平均粗さ（Ｒａ）が３μｍ以下であるのが好ましく、１μｍ以下であるのがより好ましく、０．５μｍ以下であるのが更に好ましい。
尚、算術平均粗さは、ＪＩＳ　Ｂ　０６０１、Ｂ　０６５１、Ｂ　０６５２に基づいて測定することができる。
【０１１２】
前記受像層は、以下の項目の内の１項目の物性を有することが好ましく、更に好ましくは、複数の項目、最も好ましくは、全ての項目の物性を有することが適当である。
（１）受像層のＴｇ（ガラス転移温度）が３０℃以上、トナーのＴｇ＋２０℃以下である。
（２）受像層のＴ１／２（１／２法軟化点）が、６０〜２００℃、好ましくは、８０〜１７０℃。ここで、１／２法軟化点は、特定の装置を使用し、特定の条件の下で、所定の押出加重を加えながら、初期設定温度（例えば、５０℃）で余熱時間、例えば、３００秒後に、所定の等速昇温速度で昇温した時の各温度における流出開始時と終了時のピストンストロークの差の２分の１となる温度で評価される。
（３）受像層のＴｆｂ（流出開始温度）が、４０〜２００℃、好ましくは、受像層のＴｆｂが、トナーのＴｆｂ＋５０℃以下である。
（４）受像層の粘度が１×１０^５ＣＰになる温度が、４０℃以上、トナーのそれより低い。
（５）受像層の定着温度における貯蔵弾性率（Ｇ’）が、１×１０^２〜１×１０^５Ｐａ、損失弾性率（Ｇ”が、１×１０^２〜１×１０^５Ｐａである。
（６）受像層の定着温度における損失弾性率（Ｇ”）と、貯蔵弾性率（Ｇ’）との比である損失正接（Ｇ”／Ｇ’）が、０．０１〜１０である。
（７）受像層の定着温度における貯蔵弾性率（Ｇ’）が、トナーの定着温度における貯蔵弾性率（Ｇ”）に対して、−５０〜＋２５００である。
（８）溶融トナーの受像層上の傾斜角が、５０度以下、特に４０度以下である。
また、受像層としては、特許第２７８８３５８号明細書、特開平７−２４８６３７号公報、同８−３０５０６７号公報、同１０−２３９８８９号公報等に開示されている物性等を満足するものが好ましい。
【０１１３】
前記（１）の物性は、示差走査熱量測定装置（ＤＳＣ）により測定することができる。前記（２）〜（３）の物性は、例えば、島津製作所製フローテスターＣＦＴ−５００又は５００Ｄを用いて測定することができる。前記（５）〜（７）の物性は、回転型レオメーター（例えば、レオメトリック社製ダイナミックアナライザーＲＡＤＩＩ）を用いて測定することができる。前記（８）の物性は、協和界面科学（株）製の接触角測定装置を用い、特開平８−３３４９１６号公報に開示した方法で測定することができる。
【０１１４】
前記受像層としては、１×１０^６〜１×１０^１５Ω／ｃｍ^２の範囲（２５℃、６５％ＲＨの条件にて）の表面電気抵抗を有するのが好ましい。
前記表面抵抗が１×１０^６Ω／ｃｍ^２未満であると、受像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り易いことがある一方、表面電気抵抗が、１×１０^１５Ω／ｃｍ^２を超えると、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、電子写真用受像シート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することがある。
【０１１５】
尚、前記支持体に対し、受像層と反対側の面の表面電気抵抗としては、５×１０^８〜３．２×１０^１０Ω／ｃｍ^２が好ましく、１×１０^９〜１×１０^１０Ω／ｃｍ^２がより好ましい。
本発明において、前記表面電気抵抗の測定は、ＪＩＳ　Ｋ　６９１１に準拠し、サンプルを温度２０℃、湿度６５％の環境下に８時間以上調湿し、同じ環境下で、アドバンテスト（株）製Ｒ８３４０を使用し、印加電圧１００Ｖの条件で、通電して１分間経過した後に測定することで得られる。
【０１１６】
［その他の層］
前記その他の層としては、例えば、表面保護層、バック層、密着改良層、中間層、下塗り層、クッション層、帯電調節（防止）層、反射層、色味調製層、保存性改良層、接着防止層、アンチカール層、及び、平滑化層等が挙げられる。これらの層は、単層構成であってもよく、２以上の層より構成されていてもよい。
【０１１７】
−表面保護層−
前記表面保護層は、本発明の電子写真用受像シートにおける表面の保護、保存性の改良、取り扱い性の改良、筆記性の付与、機器通過性の改良、アンチオフセット性の付与等の目的で、前記受像層の表面に設けることができる。該表面保護層は、１層であってもよいし、２層以上の層からなっていてもよい。表面保護層には、バインダーとして各種の熱可塑性樹脂、熱硬化性樹脂等を用いることができ、前記受像層と同種の樹脂を用いるのが好ましい。但し、熱力学的特性や、静電特性等は、受像層と同じである必要はなく、各々最適化することができる。
【０１１８】
前記表面保護層には、受像層に使用可能な、前述の各種の添加剤を配合することができる。特に、前記表面保護層には、本発明で使用する離型剤と共に、他の添加剤、例えば、マット剤等を配合することができる。なお、前記マット剤としては、種々の公知のものが挙げられる。
本発明の電子写真用受像シートにおける最表面層（例えば、表面保護層が形成されている場合には、表面保護層等）としては、定着性の点で、トナーとの相溶性が良いのが好ましい。具体的には、溶融したトナーとの接触角が、例えば０〜４０度であることが好ましい。
【０１１９】
−バック層−
前記バック層は、本発明の電子写真用受像シートにおいて、裏面出力適性付与、裏面出力画質改良、カールバランス改良、機器通過性改良等の目的で、支持体に対して、受像層の反対側に設けられるのが好ましい。
前記バック層の色としては、特に制限はないが、本発明の電子写真用受像シートが、裏面にも画像を形成する両面出力型受像シートの場合、バック層も白色であることが好ましい。白色度及び分光反射率は、表面と同様に８５％以上が好ましい。
また、両面出力適性改良のため、バック層の構成が受像層側と同様であってもよい。バック層には、上記で説明した各種の添加剤を用いることができる。このような添加剤として、特にマット剤や、帯電調整剤等を配合することが適当である。バック層は、単層構成であってもよく、２層以上の積層構成であってもよい。
また、定着時のオフセット防止のため、定着ローラ等に離型性オイルを用いている場合、バック層は、オイル吸収性としてもよい。
【０１２０】
−密着改良層等−
前記密着改良層は、本発明の電子写真用受像シートにおいて、支持体及び受像層の密着性を改良する目的で、形成するのが好ましい。密着改良層には、前述の各種の添加剤を配合することができ、特に架橋剤を配合するのが好ましい。また、本発明の電子写真用受像シートには、トナーの受容性を改良するため、該密着改良層及び受像層の間に、更にクッション層等を設けるのが好ましい。
【０１２１】
−中間層−
前記中間層は、例えば、支持体及び密着改良層の間、密着改良層及びクッション層の間、クッション層及び受像層の間、受像層及び保存性改良層との間等に形成することができる。もちろん、支持体、受像層、及び、中間層からなる電子写真用受像シートの場合には、中間層は、例えば、支持体及び受像層の間に存在させることができる。
【０１２２】
なお、本発明の前記電子写真用受像シートの厚みとしては、特に制限はなく、目的に応じて適宜選定することができるが、例えば、５０〜３５０μｍが好ましく、１００〜２８０μｍがより好ましい。
【０１２３】
＜画像形成＞
本発明の前記電子写真用受像シートは、電子写真方式によって電子写真用トナーによる画像形成に好適に使用することができ、電子写真用カラートナーによるカラー画像形成に好適に使用することができる。特に、前記電子写真用受像シートの搬送部と、静電潜像形成部と、現像部と、定着ベルトとを少なくとも有する画像形成装置において用いられるのが好ましい。
【０１２４】
＜＜電子写真用カラートナー＞＞
前記画像形成に用いられる電子写真用カラートナーは、結着樹脂と着色剤とを少なくとも含有し、必要に応じて離型剤、その他の成分を含有する。
【０１２５】
−トナー　結着樹脂−
前記結着樹脂としては、スチレン、パラクロルスチレンなどのスチレン類；ビニルナフタレン、塩化ビニル、臭化ビニル、弗化ビニル、酢酸ビニル、プロピオン酸ビニル、ベンゾエ酸ビニル、酪酸ビニルなどのビニルエステル類；アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ−ブチル、アクリル酸イソブチル、アクリル酸ドデシル、アクリル酸ｎ−オクチル、アクリル酸２−クロルエチル、アクリル酸フェニル、α−クロルアクリル酸メチル、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチルなどのメチレン脂肪族カルボン酸エステル類；アクリロニトリル、メタクリルロニトリル、アクリルアミドなどのビニルニトリル類；ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテルなどのビニルエーテル類；Ｎ−ビニルピロール、Ｎ−ビニルカルバゾール、Ｎ−ビニルインドール、Ｎ−ビニルピロリドンなどのＮ−ビニル化合物類；メタクリル酸、アクリル酸、桂皮酸などのビニルカルボン酸類などビニル系モノマーの単独重合体やその共重合体、更には各種ポリエステル類を使用することができ、各種ワックス類を併用することも可能である。
これらの樹脂の中で、特に本発明の受像層に用いたものと同一系統の樹脂を用いるのが好ましい。
【０１２６】
−トナー　着色剤−
前記着色剤としては、通常トナーに用いられているものを制限なく使用することができ、例えば、カーボンブラック、クロムイエロー、ハンザイエロー、ベンジジンイエロー、スレンイエロー、キノリンイエロー、パーメネントオレンジＧＴＲ、ピラゾロンオレンジ、バルカンオレンジ、ウオッチヤングレッド、パーマネントレッド、ブリリアンカーミン３Ｂ、ブリリアンカーミン６Ｂ、デイポンオイルレッド、ピラゾロンレッド、リソールレッド、ローダミンＢレーキ、レーキレッドＣ、ローズベンガル、アニリンブルー、ウルトラマリンブルー、カルコオイルブルー、メチレンブルークロライド、フタロシアニンブルー、フタロシアニングリーン、マラカイトグリーンオクサレレートなどの種々の顔料が挙げられる。また、アクリジン系、キサンテン系、アゾ系、ベンゾキノン系、アジン系、アントラキノン系、チオインジコ系、ジオキサジン系、チアジン系、アゾメチン系、インジコ系、チオインジコ系、フタロシアニン系、アニリンブラック系、ポリメチン系、トリフェニルメタン系、ジフェニルメタン系、チアジン系、チアゾール系、キサンテン系などの各種染料などが挙げられる。これら着色剤は１種単独で使用してもよいし、複数種類を併せて使用してもよい。
着色剤の含有量は、２〜８質量％の範囲が好ましい。着色剤の含有量が２質量％以上であれば着色力が弱くなることもなく、一方、８質量％以下であれば、透明性が損なわれることもないので好ましい。
【０１２７】
−トナー　離型剤−
前記離型剤としては、原理的には、公知のワックス全てが使用可能であるが、比較的低分子量の高結晶性ポリエチレンワックス、フィッシャートロプシュワックス、アミドワックス、ウレタン化合物など窒素を含有する極性ワックスなどが特に有効である。ポリエチレンワックスについては分子量が１０００以下のものが特に有効であり、３００〜１０００の範囲がより好ましい。
【０１２８】
前記ウレタン結合を有する化合物は、低分子量であっても極性基による凝集力の強さにより、固体状態を保ち、融点も分子量のわりには高く設定できるので好適である。分子量の好ましい範囲は３００〜１０００である。原料は、ジイソシアン酸化合物類とモノアルコール類との組み合わせ、モノイソシアン酸とモノアルコールとの組み合わせ、ジアルコール類とモノイソシアン酸との組み合わせ、トリアルコール類とモノイソシアン酸との組み合わせ、トリイソシアン酸化合物類とモノアルコール類との組み合わせなど、種々の組み合わせを選択することができが、高分子量化させないために、多官能基と単官能基の化合物を組み合わせることが好ましく、また等価の官能基量となるようにすることが重要である。
【０１２９】
具体的な、原料化合物のうちモノイソシアン酸化合物としては、例えば、イソシアン酸ドデシル、イソシアン酸フェニル及びその誘導体、イソシアン酸ナフチル、イソシアン酸ヘキシル、イソシアン酸ベンジル、イソシアン酸ブチル、イソシアン酸アリルなどが挙げられる。
ジイソシアン酸化合物としては、ジイソシアン酸トリレン、ジイソシアン酸４、４’ジフェニルメタン、ジイソシアン酸トルエン、ジイソシアン酸１、３−フェニレン、ジイソシアン酸ヘキサメチレン、ジイソシアン酸４−メチル−ｍ−フェニレン、ジイソシアン酸イソホロンなどが挙げられる。
モノアルコールとしては、メタノール、エタノール、プロパノール、ブタノール、ペンタノール、ヘキサノール、ヘプタノールなど極く一般的なアルコール類を使用することが可能である。
原料化合物のうちジアルコール類としては、エチレングリコール、ジエチレングリコール、トリエチレングリコール、トリメチレングリコールなど多数のグリコール類；トリアルコール類としては、トリメチロールプロパン、トリエチロールプロパン、トリメタノールエタンなどが使用可能であるが、必ずしもこの範囲に限定されない。
【０１３０】
これらのウレタン化合物類は、通常の離型剤のように、混練時に樹脂や着色剤とともに混合して、混練粉砕型トナーとしても使用できる。また、乳化重合凝集溶融法トナーに用いる場合には、水中にイオン性界面活性剤や高分子酸や高分子塩基などの高分子電解質とともに分散し、融点以上に加熱してホモジナイザーや圧力吐出型分散機で強い剪断をかけて微粒子化し、１μｍ以下の離型剤粒子分散液を調製し、樹脂粒子分散液、着色剤分散液などとともに用いることができる。
【０１３１】
−トナー　その他の成分−
また、前記トナーには、内添剤、帯電制御剤、無機微粒子等のその他の成分を配合することができる。内添剤としては、フェライト、マグネタイト、還元鉄、コバルト、ニッケル、マンガン等の金属、合金、又はこれら金属を含む化合物などの磁性体を使用することができる。
【０１３２】
前記帯電制御剤としては、４級アンモニウム塩化合物、ニグロシン系化合物、アルミや、鉄、クロムなどの錯体からなる染料、トリフェニルメタン系顔料など通常使用される種々の帯電制御剤を使用することができる。なお、凝集、溶融時の安定性に影響するイオン強度の制御や、廃水汚染を減少する観点から水に溶解しにくい材料が好ましい。
【０１３３】
前記無機微粒子としては、シリカ、アルミナ、チタニア、炭酸カルシウム、炭酸マグネシウム、リン酸三カルシウムなど、通常、トナー表面の外添剤を全て使用で、それらをイオン性界面活性剤や高分子酸、高分子塩基で分散して使用することが好ましい。
【０１３４】
更に、乳化重合、シード重合、顔料分散、樹脂粒子分散、離型剤分散、凝集、更には、それらの安定化などに界面活性剤を用いることができる。例えば、硫酸エステル塩系、スルホン酸塩系、リン酸エステル系、せっけん系等のアニオン界面活性剤、アミン塩型、４級アンモニウム塩型等のカチオン系界面活性剤、また、ポリエチレングリコール系、アルキルフェノールエチレンオキサイド付加物系、多価アルコール系等の非イオン性界面活性剤を併用することも効果的である。その際の分散手段としては、回転せん断型ホモジナイザーやメデイアを有するボールミル、サンドミル、ダイノミルなどの一般的なものが使用可能である。
【０１３５】
なお、前記トナーには、必要に応じて更に外添剤を添加してもよい。前記外添剤としては、無機粉末及び有機粒子等が挙げられる。前記無機粒子としては、ＳｉＯ_２、ＴｉＯ_２、Ａｌ_２Ｏ_３、ＣｕＯ、ＺｎＯ、ＳｎＯ_２、Ｆｅ_２Ｏ_３、ＭｇＯ、ＢａＯ、ＣａＯ、Ｋ_２Ｏ、Ｎａ_２Ｏ、ＺｒＯ_２、ＣａＯ・ＳｉＯ_２、Ｋ_２Ｏ・（ＴｉＯ_２）_ｎ、Ａｌ_２Ｏ_３・２ＳｉＯ_２、ＣａＣＯ_３、ＭｇＣＯ_３、ＢａＳＯ_４、ＭｇＳＯ_４等を例示することができる。また、前記有機粒子としては、脂肪酸又はその誘導体や、これ等の金属塩等の粉末、フッ素系樹脂、ポリエチレン樹脂、アクリル樹脂等の樹脂粉末を用いることができる。これらの粉末の平均粒径は、例えば、０．０１〜５μｍ、好ましくは、０．１〜２μｍであることが適当である。
【０１３６】
前記トナーの製造方法は、特に制限されないが、（ｉ）樹脂粒子を分散させてなる分散液中で凝集粒子を形成し凝集粒子分散液を調製する工程、（ｉｉ）前記凝集粒子分散液中に、微粒子を分散させてなる微粒子分散液を添加混合して前記凝集粒子に前記微粒子を付着させて付着粒子を形成する工程、及び（ｉｉｉ）前記付着粒子を加熱し融合してトナー粒子を形成する工程、とを含むトナーの製造方法により製造することが好ましい。
【０１３７】
−トナー物性等−
前記トナーの体積平均粒子径は０．５μｍ以上１０μｍ以下が好ましい。
前記トナーの体積平均粒子径が小さすぎると、トナーのハンドリング（補給性、クリーニング性、流動性等）に悪影響が生じる場合があり、また、粒子生産性が低下する場合がある。一方、トナーの体積平均粒子径が大すぎると、粒状性、転写性に起因する画質、解像度に悪影響を与える場合がある。
また、前記トナーは、前記トナーの体積平均粒子径範囲を満たし、かつ体積平均粒度分布指数（ＧＳＤｖ）が１．３以下であることが好ましい。
前記体積平均粒度分布指数（ＧＳＤｖ）と数平均粒度分布指数（ＧＳＤｎ）との比（ＧＳＤｖ／ＧＳＤｎ）は少なくとも０．９５が好ましい。
また、本発明のトナーは、前記トナーの体積平均粒子径範囲を満たし、かつ下記式で表される形状係数の平均値が１．００〜１．５０が好ましい。
形状係数＝〔π×（２×Ｌ）^２〕／（４×Ｓ）
（但し、Ｌはトナー粒子の最大長、Ｓはトナー粒子の投影面積を示す。）
トナーが上記条件を満たす場合には、画質、特に、粒状性、解像度に効果があり、また、転写に伴う抜けやブラーが生じにくく、平均粒径が小さくなくてもハンドリング性に悪影響が出にくくなる。
【０１３８】
なお、トナー自体の１５０℃における貯蔵弾性率Ｇ’（角周波数１０ｒａｄ／ｓｅｃで測定）は、１０〜２００Ｐａであることが、定着工程での画質向上とオフセット性の防止の面から適当である。
【０１３９】
（画像形成方法）
本発明の画像形成方法においては、少なくとも、静電潜像を形成し、該静電潜像を現像した後、本発明の前記電子写真用受像シートに転写して画像を形成し定着させる。
【０１４０】
本発明の前記画像形成方法においては、前述のほか特に制限はなく、通常の電子写真法に従って画像を形成することができるが、例えば、第１の態様として、本発明の前記電子写真用受像シートに、トナー画像を形成した後、前記電子写真用受像シートにおける該画像形成面を、定着ベルト及びローラにより、加熱及び加圧し、冷却した後、前記定着ベルトから剥離する方法が挙げられる。
また、第２の態様として、本発明の前記電子写真用受像シートに、トナー画像を形成し、熱ローラにより定着した後、更に、前記電子写真用受像シートの該画像形成面を、定着ベルト及びローラにより、加熱及び加圧し、冷却した後、前記定着ベルトから剥離する方法が挙げられる。
なお、転写の方法としては、通常の電子写真方法で使用される方法、例えば、現像ローラ上に形成したトナー画像を直接受像材料に転写する直接転写方式、或いは中間転写ベルト等に一次転写した後、受像材料に転写する中間転写ベルト方式がある。環境安定性及び高画質化の面から、中間転写ベルト方式が好ましく使用される。
【０１４１】
前記画像形成方法においては、定着ベルトを有する電子写真装置を使用して、電子写真用受像シート上に転写されたトナーが該電子写真用受像シートに定着される。ベルト定着方式としては、例えば、特開平１１−３５２８１９号公報に記載のオイルレスタイプのベルト定着方法、特開平１１−２３１６７１号公報及び特開平５−３４１６６６号公報に記載の二次転写と定着を同時に達成する方法等が知られている。本発明でいう定着ベルトを有する電子写真装置は、例えば、電子写真用受像シートの搬送部と、静電潜像形成部と、現像部と、定着ベルトとを少なくとも有する、ベルト方式のトナー定着部を有する画像形成装置が好ましく、更に、トナーを溶融し加圧し得る加熱加圧部、加熱された受像紙を定着ベルトに付着させたままの状態で冷却できる冷却部、を有する画像形成装置がより好ましい。前記定着ベルトは、トナーの付着した受像紙を受像層と接する状態で搬送することができるのが好ましい。このような定着ベルトを有する電子写真装置に受像層を有する電子写真用受像シートを使用することにより、受像層に付着したトナーが、受像紙に広がることなく細密に定着されると共に、定着ベルトに密着した状態で溶融トナーが冷却・固化するので、受像層にトナーが完全に埋め込まれた状態で受像層に受容される。従って、画像段差がなく、光沢のある平滑なトナー画像を得ることができる。
【０１４２】
本発明の電子写真用受像シートは、特にオイルレス方式のベルト定着方式による画像形成方法に好適であり、これにより、オフセットが大幅に改善される。但し、それ以外の各種の画像形成法に対しても、同様に使用することができる。
例えば、本発明の電子写真用受像シートを使用することにより、フルカラー画像を、画質の改善及びひび割れの防止を図りながら、好適に形成することができる。カラー画像の形成は、フルカラー画像を形成し得る電子写真装置を用いて行うことができる。通常の電子写真装置は、受像紙搬送部と、潜像形成部と、潜像形成部に近接して配設されている現像部とがあり、機種によっては、装置本体の中央に潜像形成部と受像紙搬送部に近接してトナー像中間転写部を有している。
【０１４３】
更に、画質の向上を図るための方法として、静電転写又はバイアスローラ転写に代わって、或いは併用して、粘着転写又は熱支援型の転写方式が知られている。例えば、特開昭６３−１１３５７６号公報、特開平５−３４１６６６号公報にはその具体的な構造が記載されている。特に熱支援型転写方式の中間転写ベルトを用いる方法が好ましい。該中間ベルトとしては、例えば、電鋳ニッケルで形成された無端状ベルトが用いられる。また、電子写真用受像シートへのトナー転写後又は転写後半の中間ベルトには冷却装置を設けることが好ましい。該冷却装置により、トナー（トナー画像）は、それに使用されるバインダー樹脂の軟化温度又はトナーのガラス転移温度＋１０℃以下に冷却され、効率よく電子写真用受像シートに転写され、中間ベルトからの剥離が可能となる。
【０１４４】
定着は、最終画像の光沢や平滑性を左右する重要な工程である。定着方式は、加熱加圧ローラによる定着、ベルトを用いたベルト定着などが知られているが、上記光沢、平滑性等の画像品質の点からはベルト定着方式の方が好ましい。ベルト定着方式については、例えば、特開平１１−３５２８１９号公報に記載のオイルレスタイプのベルト定着方法、特開平１１−２３１６７１号公報、特開平５−３４１６６６号公報に記載の二次転写と定着を同時に達成する方法等が知られている。また、定着ベルトと定着ローラによる加圧及び加熱の前に、熱ローラによる一次定着を行ってもよい。
【０１４５】
前記定着ベルトの表面は、トナーの剥離性又はトナー成分のオフセットを防止するためにシリコーン系又はフッ素系或いはその併用系の表面処理が施されていてもよい。また、定着の後半にはベルトの冷却装置を備え、電子写真用受像シートの剥離を良好にすることが好ましい。冷却温度は、トナーバインダー樹脂及び／又は電子写真用受像シートの受像層のポリマーの軟化点以下、或いはガラス転移点＋１０℃以下にすることが好ましい。一方、定着初期には、電子写真用受像シートの受像層又はトナーが十分に軟化する温度まで昇温する必要がある。具体的には冷却温度は７０℃以下、３０℃以上が実用上好ましく、定着初期においては１８０℃以下、１００℃上が好ましい。
【０１４６】
以下、典型的な定着ベルトを有する画像形成装置の一例を示す図１に基づいて具体的に説明する。なお、本発明の態様は、図１に示される態様に限定されるものではない。
まず、画像形成装置（図示せず）でトナー（１２）が電子写真用受像シート（１）に転写される。トナー（１２）が付着した受像紙（１）は、搬送設備（図示せず）でＡ点に運ばれ、加熱ローラ（１４）と加圧ローラ（１５）の間を通過し、電子写真用受像シート（１）の受像層或いはトナー（１２）が十分に軟化する温度（定着温度）及び圧力で加熱及び加圧される。
【０１４７】
ここで、定着温度とは、Ａ点における加熱ローラ（１４）と加圧ローラ（１５）とニップ部の位置で測定した受像層表面の温度を意味する。該定着の温度としては、前記電子写真用受像シートにおける受像層の材質によっても異なるが、具体的には、９０〜１２０℃が好ましく、１００〜１１０℃がより好ましく、１０３〜１０７℃が更に好ましい。また、圧力は、加熱ローラ（１４）と加圧ローラ（１５）とニップ部で測定した受像層表面の圧力を意味し、具体的には、１〜１０ｋｇ／ｃｍ^２が好ましく、２〜７ｋｇ／ｃｍ^２がより好ましい。このように加熱及び加圧され、後に電子写真用受像シート（１）が、定着ベルト（１３）により冷却装置（１６）に運ばれる間に、受像層内に離散的に存在していた離型剤（図示せず）が十分に加熱されて溶融し、受像層表面に移動する。移動してきた離型剤は、受像層表面に離型剤の層（膜）を形成する。その後、電子写真用受像シート（１）は、定着ベルト（１３）により冷却装置（１６）に運ばれて、例えば、受像層のポリマー及び／又はトナーに使用されるバインダー樹脂の軟化点以下又はガラス転移点＋１０℃以下の温度、好ましくは２０〜８０℃より好ましくは室温（２５℃）に冷却される。これにより、受像層表面に形成された離型剤の層（膜）が冷却・固化し受像層内離型剤の変剤による離型剤層を形成する。
冷却された電子写真用受像シート（１）は、更に定着ベルト（１３）によりＢ点に運ばれ、定着ベルト（１３）は、テンションローラ（１７）上を移動する。従って、Ｂ点にて電子写真用受像シート（１）と定着ベルト（１３）が剥離する。なお、電子写真用受像シートが自身の剛性（腰の強さ）でベルトから剥離するようにテンションロールの径を小さく設定することが好ましい。
【０１４８】
ここで、前記画像形成装置に使用される定着ベルトとしては、例えば、ポリイミド、電鋳ニッケル及びアルミニウム等を基材として形成された無端状ベルトであることが適当である。
前記定着ベルトの表面には、シリコーンゴム、フッ素ゴム、シリコーン樹脂、フッ素樹脂からなる群より選択される少なくとも１種以上からなる薄膜が形成されることが好ましい。これらの中でも、定着ベルトの表面に均一な厚さのフルオロカーボンシロキサンゴム製の層を設ける態様、前記定着ベルトの表面に均一な厚さのシリコーンゴム製の層を有し、かつ該シリコーンゴム層の表面にフルオロカーボンシロキサンゴム製の層を設ける態様が好ましい。
【０１４９】
前記フルオロカーボンシロキサンゴムとしては、主鎖にパーフルオロアルキルエーテル基及び／又はパーフルオロアルキル基を有するものが好ましい。
このようなフルオロカーボンシロキサンゴムとしては、（Ａ）下記一般式（１）のフルオロカーボンシロキサンを主成分とし、脂肪族不飽和基を有するフルオロカーボンポリマー、（Ｂ）１分子中に２個以上の≡ＳｉＨ基を含有し、上記フルオロカーボンシロキサンゴム組成物中の脂肪族不飽和基量に対して上記≡ＳｉＨ基の含有量が１〜４倍モル量であるオルガノポリシロキサン及び／又はフルオロカーボンシロキサン、（Ｃ）充填剤、（Ｄ）有効量の触媒を含有するフルオロカーボンシロキサンゴム組成物の硬化物が好適に用いられる。
【０１５０】
前記（Ａ）成分のフルオロカーボンポリマーは、下記一般式（１）で示される繰り返し単位を有するフルオロカーボンシロキサンを主成分とし、脂肪族不飽和基を有するものである。
【０１５１】
【化１】

【０１５２】
ここで、上記式（１）において、Ｒ^１０は非置換又は置換の好ましくは炭素数１〜８の一価炭化水素基であり、好ましくは炭素数１〜８のアルキル基又は炭素数２〜３のアルケニル基であり、特にメチル基であることが好ましい。ａ，ｅはそれぞれ０又は１、ｂ，ｄはそれぞれ１〜４の整数、ｃは０〜８の整数である。また、ｘは１以上の整数、好ましくは１０〜３０である。
【０１５３】
このような（Ａ）成分としては、下記式（２）で示すものを挙げることができる。
【０１５４】
【化２】

【０１５５】
（Ｂ）成分において、≡ＳｉＨ基を有するオルガノポリシロキサンとしては、ケイ素原子に結合した水素原子を分子中に少なくとも２個有するオルガノハイドロジェンポリシロキサンを挙げることができる。
【０１５６】
また、本発明で用いるフルオロカーボンシロキサンゴム組成物においては、（Ａ）成分のフルオロカーボンポリマーが脂肪族不飽和基を有するものであるときには、硬化剤として上述したオルガノハイドロジェンポリシロキサンを使用することができる。即ち、この場合には、フルオロカーボンシロキサン中の脂肪族不飽和基と、オルガノハイドロジェンポリシロキサン中のケイ素原子に結合した水素原子との間で生ずる付加反応によって硬化物が形成されるものである。
【０１５７】
このようなオルガノハイドロジェンポリシロキサンとしては、付加硬化型のシリコーンゴム組成物に使用される種々のオルガノハイドロジェンポリシロキサンを使用することができる。
【０１５８】
上述したオルガノハイドロジェンポリシロキサンは、一般にその≡ＳｉＨ基の数が、（Ａ）成分のフルオロカーボンシロキサン中の脂肪族不飽和炭化水素基１個に対して、少なくとも１個、特に１〜５個となるような割合で配合することが好適である。
【０１５９】
また、≡ＳｉＨ基を有するフルオロカーボンとしては、上記式（１）の単位又は式（１）においてＲ^１０がジアルキルハイドロジェンシロキシ基であり、かつ末端がジアルキルハイドロジェンシロキシ基又はシリル基等の≡ＳｉＨ基であるものが好ましく、下記式（３）で示すものを挙げることができる。
【０１６０】
【化３】

【０１６１】
（Ｃ）成分の充填剤としては、一般的なシリコーンゴム組成物に使用されている種々の充填剤を用いることができる。例えば、煙霧質シリカ、沈降性シリカ、カーボン粉末、二酸化チタン、酸化アルミニウム、石英粉末、タルク、セリサイト及びベントナイト等の補強性充填剤、アスベスト、ガラス繊維、有機繊維等の繊維質充填剤などを例示することができる。
【０１６２】
（Ｄ）成分の触媒としては、付加反応用触媒として公知とされている塩化白金酸、アルコール変性塩化白金酸、塩化白金酸とオレフィンとの錯体、白金黒又はパラジウムをアルミナ、シリカ、カーボンなどの担体に担持したもの、ロジウムとオレフィンとの錯体、クロロトリス（トリフェニルフォスフィン）ロジウム（ウィルキンソン触媒）、ロジウム（ＩＩＩ）アセチルアセトネートなどのような周期律表第ＶＩＩＩ族元素又はその化合物が例示されるが、これらの錯体はアルコール系、エーテル系、炭化水素などの溶剤に溶解して用いることが好ましい。
【０１６３】
本発明で用いるフルオロカーボンシロキサンゴム組成物においては、耐溶剤性を向上させるという本発明の目的を損なわない範囲において、種々の配合剤を添加することができる。例えば、ジフェニルシランジオール、低重合度の分子鎖末端水酸基封鎖ジメチルポリシロキサン、ヘキサメチルジシラザン等の分散剤、酸化第一鉄、酸化第二鉄、酸化セリウム、オクチル酸鉄等の耐熱性向上剤、顔料等の着色剤等を必要に応じて配合することができる。
【０１６４】
前記定着用ベルトは、耐熱性樹脂製又は金属製のベルト本体の表面を上記フルオロカーボンシロキサンゴム組成物で被覆し、加熱硬化することによって得られるが、必要に応じて更に、ｍ−キシレンヘキサフロライド、ベンゾトリフロライド等の溶剤で希釈して塗工液とし、スプレーコート、ディップコート及びナイフコート等の一般的なコーティング法によって塗布することができる。また、加熱硬化の温度、時間は適宜選定することができ、通常温度１００〜５００℃、時間５秒〜５時間の範囲でベルト本体の種類及び製造方法などに応じて選択される。
【０１６５】
前記定着ベルトの表面に形成するフルオロカーボンシロキサンゴム層の厚さは特に限定されるものではないが、トナーの剥離性或いはトナー成分のオフセットを防止して画像の良好な定着性を得るために２０〜５００μｍ、特に４０〜２００μｍが好ましい。
【０１６６】
本発明の電子写真用受像シートに画像を形成する方法は、定着ベルトを使用した前記本発明の画像形成方法であれば、特に、図１に示した方法に制限されるものではない。
例えば、本発明の画像形成方法においては、カラー画像を好ましく形成することができる。カラー画像の形成は、フルカラー画像を形成し得る電子写真装置を用いて行うことができる。通常の電子写真装置は、受像シート搬送部と、潜像形成部と、潜像形成部に近接して配設されている現像部とがあり、機種によっては、装置本体の中央に潜像形成部と受像シート搬送部に近接してトナー像中間転写部を有している。
【０１６７】
更に、画質の向上を図るための方法として、静電転写或いはバイアスローラ転写に代わって、或いは併用して、粘着転写又は熱支援型の転写方式が知られている。例えば、特開昭６３−１１３５７６号公報及び特開平５−３４１６６６号公報にはその具体的な構造が記載されている。特に熱支援型転写方式の中間転写ベルトを用いた方法は、小粒径のトナーを使用する場合には好ましい。
【０１６８】
本発明の画像形成方法によれば、定着オイルのないオイルレス機を使用しても、受像シート及びトナーの剥離性、或いは受像シート及びトナー成分のオフセットを防止でき、安定した給紙を実現できると共に、これまでにない良好な光沢性を有し、写真感覚に富む、良好な画像を実現できる。
【０１６９】
本発明の画像形成方法においては、特に、光沢度が良好な画像を形成可能である点で、定着の際、電子写真用受像シートにおける受像層において、支持体に最も近い層に含まれる樹脂の溶融粘度が、他の層に含まれる樹脂の溶融粘度以上であるのが好ましい。具体的には、定着の際、受像層における積層された各層のうち、支持体に最も遠い層に含まれる樹脂の溶融粘度の３倍以上であるのが好ましく、１０倍以上であるのがより好ましい。また、電子写真用受像シートにおける受像層が３層以上の多層構成である場合には、定着の際、受像層において、支持体に最も近い層及び支持体に最も遠い層に含まれる樹脂の溶融粘度が、該支持体に最も近い層及び支持体に最も遠い層以外の層に含まれる樹脂の溶融粘度以上であるのが好ましい。
尚、前記溶融粘度は、公知の溶融粘度測定装置により、樹脂を溶融状態にした際の粘度乃至剪断弾性率を測定し求めることができる。
【０１７０】
前記電子写真用受像シートは、特にオイルレス方式のベルト定着方式による画像形成方法に好適であり、これにより、オフセットが大幅に改善される。但し、それ以外の各種の画像形成方法においても、同様に使用することができる。
例えば、前記電子写真用受像シートを使用することにより、フルカラー画像を、画質の改善及びひび割れの防止を図りながら、好適に形成することができる。カラー画像の形成は、フルカラー画像を形成し得る電子写真装置を用いて行うことができる。通常の電子写真装置は、受像紙搬送部と、潜像形成部と、潜像形成部に近接して配設されている現像部とがあり、機種によっては、装置本体の中央に潜像形成部と受像紙搬送部に近接してトナー像中間転写部を有している。
【０１７１】
更に、画質の向上を図るための方法として、静電転写又はバイアスローラ転写に代わって、或いは併用して、粘着転写又は熱支援型の転写方式が知られている。例えば、特開昭６３−１１３５７６号公報、特開平５−３４１６６６号公報にはその具体的な構造が記載されている。特に熱支援型転写方式の中間転写ベルトを用いる方法が好ましい。該中間ベルトとしては、例えば、電鋳ニッケルで形成された無端状ベルトが用いられる。また、電子写真用受像シートへのトナー転写後又は転写後半の中間ベルトには冷却装置を設けることが好ましい。該冷却装置により、トナー（トナー画像）は、それに使用されるバインダー樹脂の軟化温度又はトナーのガラス転移温度以下に冷却され、効率よく電子写真用受像シートに転写され、中間ベルトからの剥離が可能となる。
【０１７２】
定着は、最終画像の光沢や平滑性を左右する重要な工程である。定着方式は、加熱加圧ローラによる定着、ベルトを用いたベルト定着などが知られているが、上記光沢、平滑性等の画像品質の点からはベルト定着方式の方が好ましい。ベルト定着方式については、例えば、特開平１１−３５２８１９号公報に記載のオイルレスタイプのベルト定着方法、特開平１１−２３１６７１号公報、特開平５−３４１６６６号公報に記載の二次転写と定着を同時に達成する方法等が知られている。また、定着ベルトと定着ローラによる加圧及び加熱の前に、熱ローラによる一次定着を行ってもよい。
【０１７３】
また、定着の際、前記ベルトの表面の設定温度としては、電子写真用受像シートにおける受像層を前述の定着温度の数値範囲内に設定し得るのが好ましく、定着機の搬送速度（ｍｍ／ｓｅｃ）によっても異なるが、具体的には、１３０〜１６０℃程度が好ましく、１４０〜１５０℃程度がより好ましい。また定着機の搬送速度（ｍｍ／ｓｅｃ）としては、特に制限はなく、目的に応じて適宜選定されるが、５〜２００ｍｍ／ｓｅｃ程度が好ましく、２０〜６０ｍｍ／ｓｅｃ程度がより好ましい。
【０１７４】
以上により、本発明の前記電子写真用受像シートに前記電子写真用トナーによる画像、前記電子写真用カラートナーによるカラー画像が形成される。本発明の電子写真用受像シートは、銀塩写真プリント同様の画像、質感（光沢性、均一性、厚さ、腰、手触り感等）、取扱性（耐光性、暗所保存性、耐水性、耐接着性、耐傷性、耐カール性、廃棄時の破れ易さ等）などを有し、更に銀塩写真プリントよりも優れた特性、例えば両面出力、裏面筆記性などを有し、特に光沢度の極めて良好な画像が形成されると共に、湿度変化による面状悪化が抑制され、高品質な画像を形成することができる。このため、本発明の電子写真用受像シートは、各種分野において好適に使用することができるが、特にフォトペーパーとして好適に使用することができる。
【０１７５】
【実施例】
以下、本発明の実施例について説明するが、本発明はこれらの実施例に何ら限定されるものではない。なお、以下において、「％」及び「部」は、それぞれ「質量％」及び「質量部」を表す。
【０１７６】
（実施例１）
−支持体の調製−
広葉樹晒クラフトパルプ（ＬＢＫＰ）をディスクリファイナーで３００ｃｃ（カナダ標準ろ水度、Ｃ．Ｆ．Ｓ．）まで叩解し、繊維長０．５８ｍｍに調整した。このパルプ紙料に対して、パルプの質量に基づいて、以下の割合で添加剤を添加した。
・カチオン澱粉・・・・・・・・・・・・・・・１．２％
・アルキルケテンダイマー（ＡＫＤ）・・・・・・０．５％
・アニオンポリアクリルアミド・・・・・・・・０．３％
・エポキシ化脂肪族アミド（ＥＦＡ）・・・・・・０．２％
・ポリアミドポリアミンエピクロルヒドリン・・０．３％
なお、前記アルキルケテンダイマー（ＡＫＤ）におけるアルキル部分は、ベヘン酸を主体とする脂肪酸に由来しており、前記エポキシ化脂肪族アミド（ＥＦＡ）における脂肪酸部分は、ベヘン酸を主体とする脂肪酸に由来している。
【０１７７】
以上により得たパルプ紙料を、長網抄紙機により坪量１５０ｇ／ｍ^２である原紙を作製した。なお、長網抄紙機の乾燥ゾーンの中間でサイズプレス装置により、ポリビニルアルコール（ＰＶＡ）１．０ｇ／ｍ^２、ＣａＣｌ_２０．８ｇ／ｍ^２付着させた。そして、抄紙工程の最後においてソフトカレンダーを用いて密度を１．０１ｇ／ｃｍ^３に調整した。以上により得た基紙に対し、受像層を形成する側が金属ロール（表面温度：１４０℃）が接するようにしてこれを通した。以上により支持体を得た。該支持体における王研式平滑度は、２６５秒であり、ステヒキト・サイズ度は、１２７秒であった。
【０１７８】
−受像層用（上層）塗布液の調製−
下記受像層用（上層）塗布液の成分を混合し攪拌して受像層用塗布液を調製した。
【０１７９】
−−受像層（上層）用塗布液の成分−−
・カルナバワックス（中京油脂社製；セロゾール５２４）・・・１５．０ｇ
・ポリエステル樹脂水分散物（ユニチカ社製；固形分３０％、Ｔｇ＝４８℃、ＫＺＡ−７０４９）・・・１００．０ｇ
・増粘剤（明成化学社製；アルコックスＥ３０）・・・３．０ｇ
・アニオン界面活性剤（ＡＯＴ）・・・０．５ｇ
・イオン交換水・・・８０ｍｌ
調製した受像層（上層）用塗布液の粘度は７８ｍＰａ・ｓであり、表面張力は３２ｍＮ／ｍであった。
【０１８０】
−受像層（下層；支持体に最も近い層）用塗布液の調製−
下記受像層（下層）用塗布液の成分を混合し攪拌して受像層（下層）用塗布液を調製した。
【０１８１】
−−受像層（下層）用塗布液の成分−−
・スチレンアクリルワニス・・・・・・１００．０ｇ
（固形分２６．８％、Ｔｇ＝６２℃、ＢＨ−９９７Ｌ、星光化学社製）
・アニオン界面活性剤（ＡＯＴ）・・・１．５ｇ
・イオン交換水・・・・・・・・・・・２０ｍｌ
【０１８２】
得られた受像層（下層）用塗布液の粘度は２８ｍＰａ・ｓであり、表面張力は３４ｍＮ／ｍであった。
【０１８３】
−バック層用塗布液の調製−
下記バック層用塗布液の成分を混合し攪拌してバック層用塗布液を調製した。
【０１８４】
−−バック層用塗布液−−
・アクリル樹脂水分散物・・・１５０．０ｇ
（大日本インキ社製；ディックファインＫ−９６、固形分３０％）
・マット剤（積水化成品工業社製；テクポリマーＭＢＸ−８）・・・８．０ｇ
・離型剤（中京油脂社製；ハイドロンＤ３３７）・・・５．０ｇ
・アニオン界面活性剤（ＡＯＴ）・・・０．５ｇ
・イオン交換水・・・４０ｍｌ
【０１８５】
調製したバック層用塗布液の粘度は、６０ｍＰａ・ｓであり、表面張力は３４ｍＮ／ｍであった。
【０１８６】
−受像層の形成−
上記支持体の裏面に、調製したバック層用塗布液をバーコーターを用いて塗布した。次に、該支持体の表面に、調製した受像層（下層）用塗布液及び受像層（上層）用塗布液をバーコーターを用いて順次塗布し受像層を形成した。塗布量は、前記バック層については、乾燥質量で９．５ｇ／ｍ^２であり、受像層（下層；支持体に最も近い層）については、５．０ｇであり、受像層（上層）については、乾燥質量で１０．０ｇであった。
バック層及び受像層は、塗布後、オンラインで熱風により乾燥した。乾燥は、バック面及びトナー受像面ともに塗布後２分以内に乾燥するように、乾燥風量及び温度を調整した。乾燥点は、塗布表面温度が乾燥風の湿球温度と同じ温度となる点とした。
乾燥後、カレンダー処理を行った。カレンダー処理は、グロスカレンダーを用い、金属ローラを５０℃に温調した状態で、圧力１４７Ｎ／ｃｍ（１５Ｋｇｆ／ｃｍ）にて行った。
以上により電子写真用受像シートを製造した。
【０１８７】
−画像の形成−
製造した電子写真用受像シートに対し、以下のようにしてカラー画像形成を行った。
カラー画像形成装置として、電子写真プリンタ（富士ゼロックス（株）製；ＤｏｃｕＣｅｎｔｒｅ　Ｃｏｌｏｒ　４００ＣＰ）を用いた。なお、該電子写真プリンタは、定着部を、図１に示すような定着機に代えて使用した。この電子写真プリンタを用いて、２３℃、５５％ＲＨの条件下、白地から最大濃度（黒）まで、段階的に濃度を変化させた灰色の長方形画像及び青色の長方形画像を形成した。そして、これらの画像形成後に、図１に示す定着機を備えたベルト定着方式のカラー画像形成装置により、画像形成面を上向きにして定着を行った。
【０１８８】
前記カラー画像形成装置は、静電潜像担持体と、静電潜像形成手段と、現像手段と、転写手段と、定着手段とを備えている。前記静電潜像形成手段は帯電器と露光器とを有し、前記現像手段はシアントナー、イエロートナー、マゼンタトナー、及びブラックトナーの各トナー用現像器を有し、前記転写手段は中間転写ベルトを有し、前記定着手段は図１に示す定着機を有する。
【０１８９】
前記カラー画像形成装置においては、前記静電潜像形成手段により、長方形画像の静電潜像が形成される。前記現像手段により、シアン、イエロー、マゼンタ、ブラックの各色の電子写真用トナーを用いて前記長方形画像の静電潜像が現像されて、段階的に濃度を変化させた灰色の長方形画像及び青色の長方形画像が形成された。前記転写手段により、前記段階的に濃度を変化させた灰色の長方形画像及び青色の長方形画像が上記電子写真用受像シートに転写される。前記定着手段により、上記電子写真用受像シートに転写された、段階的に濃度を変化させた灰色の長方形画像及び青色の長方形画像が定着された。その結果、該電子写真用受像シート上に、段階的に濃度を変化させた灰色の長方形画像及び青色の長方形画像が形成された。
【０１９０】
この実施例において、定着ベルト１３の搬送速度は５２ｍｍ／秒であり、前記ニップ部のニップ圧（加熱ローラ１４と加圧ローラ１５とにより押圧された定着ベルト１３と加圧ローラ１５との間のニップ圧）は０．１５ＭＰａ（２ｋｇｆ／ｃｍ^２）であり、加熱ローラ１４の設定温度、即ち定着温度は１０５℃であり、加圧ローラ１５の設定温度は１４５℃であり、冷却装置１６で冷却され、電子写真受像紙１を剥離する時点での定着ベルト１３の温度は５０℃以下である。
定着ベルト基材として、ポリイミド製のベース層上に東レ・ダウコーニング・シリコーン社製　シリコーンゴム用プライマーであるＤＹ３９−１１５を塗布後、風乾３０分の後、シリコーンゴム前駆体であるＤＹ３５−７９６ＡＢ　１００質量部とｎ−ヘキサン　３０質量部により調整した塗布液を浸漬塗布により塗膜を形成し、１２０℃で１０分の一次加硫を行い、シリコーンゴム４０μｍを得た。
このシリコーンゴム層上に、信越化学工業社製　フルオロカーボンシロキサンゴム前駆体であるＳＩＦＥＬ６１０　１００質量部とフッ素系溶媒（ｍ−キシレンヘキサフロライド、パーフロロアルカン、パーフロロ（２−ブチルテトラヒドロフラン）の混合溶剤）　２０質量部により調整した塗布液を浸漬塗布により塗膜を形成した後、１２０℃で１０分の一次加硫、１８０℃で４時間の二次加硫を行い、フルオロカーボンシロキサンゴムが２０μｍの膜厚を有する定着ベルトを用いた。
【０１９１】
＜光沢度測定＞
電子写真用受像シートに形成した画像について、各灰色濃度部を光沢度測定装置（マイクロトリグロス、東洋精機製作所製）にて測定した。角度２０度で測定した際の最低光沢度値を表１及び図２に示す。また、以下のようにしてレリーフ角度を測定した。結果を表１に示す。また、レリーフ角度と、受像層（下層）用塗布液に用いた樹脂におけるガラス転移温度（℃）との関係を図３に示す。
【０１９２】
−レリーフ角度の測定方法−
画像上の黒部と白部との境界領域を、黒田精工（株）製ナノメトロ１１０Ｆを用い、ピッチ０．０１、カットオフ０．０５にて表面形状測定し、その形状より角度を求めた。
【０１９３】
＜湿度変化による面状変化観察＞
電子写真用受像シートについて、以下のようにして、湿度変化による面状変化観察を行い、下記評価基準により評価した。結果を表１に示す。
黒部と白部とを含む画像を、２３℃−８０％ＲＨ環境下で出力し、同環境下で１晩経時させた。プリントを同環境雰囲気にて密閉容器に入れ、それを容器毎２３℃−３０％ＲＨ環境下に移し、同環境下にて開封し、面状の変化を目視にて観察し、下記評価基準により評価した。
【０１９４】
−評価基準−
・○：湿度変化に伴う非光沢化（面表面における凹凸の増加）が僅かに観察されるだけで、面状変化は殆ど無い。
・△：湿度変化に伴う非光沢化（面表面における凹凸の増加）が若干観察され、面状変化が若干在る。
・×：湿度変化に伴う非光沢化（面表面における凹凸の増加）やひび割れが観察され、面状変化が著しい。
【０１９５】
（実施例２〜６及び比較例１〜３）
実施例１において、「受像層（下層）用塗布液の成分」におけるスチレンアクリルワニスを、表１に示す成分に代えたほかは、実施例１と同様にして電子写真用受像シートを作製し、同様にして評価した。結果を表１及び図２〜３に示す。
【０１９６】
【表１】

【０１９７】
但し、表１において、「＊１」は、ＳＢＲラテックス（ニッポールシリーズ、日本ゼオン社製）であり、「＊２」は、ＮＢＲラテックス（ソープフリー型、日本ゼオン社製）であり、「＊３」は、コアシェルスチレンアクリルラテックス（ソープフリー型、Ｔｇ（コア／シェル）＝７０／１０７℃（全体Ｔｇ＝１５℃）、質量比（コア／シェル）＝１／１）、「＊４」は、ポリエステルラテックス（数平均分子量＝６，５００、Ｍｗ／Ｍｎ＝２．４）、「＊５」は、スチレンアクリルラテックス（アクアブリッドシリーズ、ダイセル化学社製）、「＊６」は、コアシェルラテックス（コア／シェル＝ポリスチレン／変性ＳＢＲ、Ｔｇ（コア／シェル）＝１００／０℃（全体Ｔｇ＝約１００℃））である。
【０１９８】
実施例では、受像層（下層）に含まれる樹脂のガラス転移温度（Ｔｇ）が受像層（上層）に含まれる樹脂のガラス転移温度以上であり、また、受像層（下層）の硬度が受像層（上層）の硬度以上であって、画像における光沢度に優れ、かつ、湿度変化による面状変化が抑制されていたことが解った。
【０１９９】
（実施例７）
実施例１の「受像層の形成」において、調製した受像層（下層）用塗布液及び受像層（上層）用塗布液を、同時に支持体表面に塗布したほかは、実施例１と同様にして受像層を形成し、画像を形成し、各測定を行ったところ、実施例１と同様に優れた結果が得られた。
【０２００】
【発明の効果】
本発明によると、従来における諸問題を解決し、銀塩写真プリント同様の画像、質感（例えば、光沢性、均一性、厚さ、腰、手触り感等）、取扱性（例えば、耐光性、暗所保存性、耐水性、耐接着性、耐傷性、耐カール性、廃棄時の破れ易さ等）などを有し、更に、銀塩写真プリントよりも優れた特性（例えば、両面出力、裏面筆記性等）を有し、特に光沢度の極めて良好な画像が形成されると共に、湿度変化による面状悪化が抑制された電子写真用受像シートを提供することができる。
【図面の簡単な説明】
【図１】図１は、定着ベルト方式の電子写真装置の一例を示す概略図である。
【図２】図２は、受像層（下層）（支持体に最も近い層）用塗布液に含まれる樹脂のガラス転移温度（Ｔｇ）と最低光沢度との関係を示すグラフである。
【図３】図３は、レリーフ角度と、受像層（下層）用塗布液に用いた樹脂におけるガラス転移温度（℃）との関係を示すグラフである。
【符号の説明】
１　　電子写真用受像シート
１２　　トナー
１３　　定着ベルト
１４　　加熱ローラ
１５　　加圧ローラ
１６　　冷却装置
１７　　テンションローラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image-receiving sheet having an image, texture, handleability and the like similar to a silver salt photographic print, and an image forming method using the same.
[0002]
[Prior art]
Conventionally, image formation by electrophotography has been widely performed. Although plain paper has been used for image formation by the electrophotographic method, recently, with the spread and development of the formation technology of multicolor images and full color images by the electrophotographic method, high-quality multicolor or full color Development of electrophotographic image-receiving sheets capable of forming such images has been actively conducted. In general, this electrophotographic image-receiving sheet has the same image, texture (high gloss, uniformity, thickness, waist, texture, etc.) as the silver halide photographic print, and handleability (light resistance, dark storage stability, water resistance) , Adhesion resistance, scratch resistance, curl resistance, tearability at the time of disposal, etc.), and more excellent properties than silver halide photographic prints, such as double-sided output, backside writing, etc. It is required to be usable as paper.
[0003]
However, a high-quality electrophotographic image-receiving sheet satisfying the above-mentioned characteristics has not yet been provided, and in particular, in an electrophotographic image-receiving sheet, it is considered to make an image-receiving layer multi-layered in order to achieve various performances required. ing.
For example, Patent Document 1 proposes an electrophotographic copying sheet in which a resin layer having a fluidization temperature lower than that of a toner resin is provided on a support. The surface protection is imparted by having a high structure.
Patent Document 2 discloses a transfer sheet in which at least a transfer layer and an uppermost layer are laminated in this order on a support, and the glass transition temperature of the material constituting the uppermost layer is set to 27 ° C. or higher and 100 ° C. or lower. Therefore, blocking resistance is imparted.
However, an electrophotographic image-receiving sheet that has excellent glossiness of an image to be formed and can withstand changes in humidity has not yet been provided, and the present situation is that further improvement and development are desired.
[0004]
[Patent Document 1]
JP-A-4-212168
[Patent Document 2]
JP 2001-80294 A
[0005]
[Problems to be solved by the invention]
An object of the present invention is to solve the conventional problems and to solve the following problems. That is, the present invention has the same image, texture (for example, glossiness, uniformity, thickness, waist, touch feeling, etc.) and handleability (for example, light resistance, dark storage stability, water resistance, Adhesive properties, scratch resistance, curl resistance, tearability at the time of disposal, etc.), and further superior properties (for example, double-sided output, backside writing properties, etc.) In particular, an object of the present invention is to provide an electrophotographic image-receiving sheet in which an image having an extremely good glossiness is formed and the surface deterioration due to humidity change is suppressed, and an image forming method using the same.
[0006]
[Means for Solving the Problems]
Means for solving the problems are as follows. That is,
<1> An image receiving layer having a laminated structure of two or more layers on a support, wherein the hardness of the layer closest to the support in the image receiving layer is equal to or higher than the hardness of other layers. It is an electrophotographic image receiving sheet.
<2> The image receiving layer according to <1>, wherein a melt viscosity at a fixing temperature of a resin contained in a layer closest to the support is not less than a melt viscosity at a fixing temperature of a resin contained in another layer. It is an electrophotographic image receiving sheet.
<3> The electrophotographic image-receiving sheet according to <2>, wherein the fixing temperature is 90 to 120 ° C.
<4> From the above <1> to <3>, in the image receiving layer, the glass transition temperature (Tg) of the resin contained in the layer closest to the support is not less than the glass transition temperature (Tg) of the resin contained in the other layer. The electrophotographic image-receiving sheet according to any one of the above.
<5> From the above <1> to <4>, in the image receiving layer, the flow start temperature (Ts) of the resin contained in the layer closest to the support is not less than the flow start temperature (Ts) of the resin contained in the other layer. The electrophotographic image-receiving sheet according to any one of the above.
<6> On the support, the image receiving layer has a laminated structure of at least two layers. In the image receiving layer, the glass transition temperature (Tg) of the resin contained in the layer closest to the support is 80 ° C. or higher. An electrophotographic image-receiving sheet characterized by the above.
<7> Any of the above <1> to <6>, wherein in the image receiving layer, the layer closest to the support contains a resin having a glass transition temperature (Tg) of 80 ° C. or higher and a resin having a glass transition temperature (Tg) of 25 ° C. or lower. An electrophotographic image-receiving sheet according to claim 1.
<8> On the support, it has an image receiving layer composed of at least two layers, and in the image receiving layer, the layer closest to the support has a glass transition temperature (Tg) in the core portion of 80 ° C. or higher. An electrophotographic image-receiving sheet comprising a core / shell type resin having a glass transition temperature (Tg) at a shell portion of 25 ° C. or less and a core / shell content ratio (mass ratio) of 1 or more. .
<9> The image receiving layer has a multilayer structure of three or more layers, and in the image receiving layer, the hardness of the layer closest to the support and the layer farthest from the support is the highest in the layer closest to the support and the support. The electrophotographic image-receiving sheet according to any one of <1> to <8>, wherein the electrophotographic image-receiving sheet is not less than the hardness of a layer other than a distant layer.
<10> The image receiving layer has a multilayer structure of three or more layers, and the melt viscosity at the fixing temperature of the resin contained in the layer closest to the support and the layer farthest from the support in the image receiving layer is The electrophotographic image-receiving sheet according to any one of <1> to <9>, wherein the resin contained in a layer other than the closest layer and the layer farthest from the support has a melt viscosity equal to or higher than the melt viscosity at the fixing temperature.
<11> Any one of <1> to <10>, wherein the thermoplastic resin contained in at least the image receiving layer on the outermost surface is a self-dispersing water-based polyester resin emulsion that satisfies the following characteristics (1) to (4): The electrophotographic image-receiving sheet described in 1.
(1) Number average molecular weight (Mn) = 5000 to 10,000
(2) Molecular weight distribution (mass average molecular weight / number average molecular weight) ≦ 4
(3) Glass transition temperature (Tg) = 40-100 ° C.
(4) Volume average particle diameter = 20 to 200 nmφ
<12> The electrophotographic image-receiving sheet according to any one of <1> to <11>, wherein the at least one image-receiving layer contains a wax having a melting point of 70 ° C to 95 ° C.
<13> The electrophotographic image-receiving sheet according to any one of <1> to <10>, wherein the support is selected from a base paper, a synthetic paper, a synthetic resin sheet, a coated paper, and a laminated paper.
<14> Any one of <1> to <11>, which is used in an image forming apparatus having at least an electrophotographic image-receiving sheet conveying unit, an electrostatic latent image forming unit, a developing unit, and a fixing belt. An electrophotographic image receiving sheet.
<15> The electrophotographic image-receiving sheet according to <14>, wherein a fluorocarbonsiloxane rubber layer having a uniform thickness is provided on the surface of the fixing belt.
<16> The electrophotograph according to <14>, wherein the surface of the fixing belt has a silicone rubber layer having a uniform thickness, and the surface of the silicone rubber layer is provided with a fluorocarbonsiloxane rubber layer. This is an image receiving sheet.
<17> The electrophotographic image-receiving sheet according to <15> or <16>, wherein the fluorocarbon siloxane rubber has a perfluoroalkyl ether group and / or a perfluoroalkyl group in a main chain.
<18> At least after forming an electrostatic latent image and developing the electrostatic latent image, the image is transferred to the electrophotographic image-receiving sheet according to any one of <1> to <17> to form an image. An image forming method characterized by fixing.
<19> In the image forming method according to <18>, in the image-receiving layer, the melt viscosity of the resin contained in the layer closest to the support is equal to or higher than the melt viscosity of the resin contained in the other layer. is there.
<20> The image receiving layer has a multilayer structure of three or more layers, and at the time of fixing, the melt viscosity of the resin contained in the layer closest to the support and the layer farthest from the support in the image receiving layer The image forming method according to the above <18> or <19>, which is equal to or higher than the melt viscosity of the resin contained in a layer other than the closest layer and the layer farthest from the support.
[0007]
The electrophotographic image-receiving sheet of the present invention has, as a first aspect, an image-receiving layer having a laminated structure of two or more layers on a support, and in the image-receiving layer, the hardness in the layer closest to the support is It is more than the hardness in other layers. The electrophotographic image-receiving sheet of the present invention has, as a second aspect, an image-receiving layer having a laminated structure of at least two layers on the support, and in the image-receiving layer, the layer closest to the support. The glass transition temperature (Tg) of the resin contained is 80 ° C. or higher. The electrophotographic image-receiving sheet of the present invention has, as a third embodiment, an image-receiving layer having a laminated structure of at least two layers on a support, and the image-receiving layer has a layer closest to the support. A core / shell type in which the glass transition temperature (Tg) in the core portion is 80 ° C. or higher, the glass transition temperature (Tg) in the shell portion is 25 ° C. or lower, and the core / shell content ratio (mass ratio) is 1 or higher. Contains resin. As a result, the image, texture (for example, glossiness, uniformity, thickness, waist, feeling of touch, etc.) and handleability (for example, light resistance, storage stability in the dark, water resistance, adhesion resistance) , Scratch resistance, curl resistance, ease of tearing at the time of disposal, etc., and further superior properties (for example, double-sided output, backside writing properties, etc.), especially glossiness Thus, it is possible to provide an electrophotographic image-receiving sheet in which a very good image is formed and the surface deterioration due to humidity change is suppressed.
[0008]
In the image forming method of the present invention, at least an electrostatic latent image is formed, the electrostatic latent image is developed, and then transferred to the electrophotographic image receiving sheet of the present invention to form and fix the image. As a result, even if an oilless machine without fixing oil is used, stable paper feeding without offsetting to the fixing roll and fixing belt can be realized, and it has unprecedented good glossiness and has a photographic feel. A rich image can be realized.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
(Electrophotographic image-receiving sheet)
The electrophotographic image-receiving sheet of the present invention has an image-receiving layer on a support, and other layers appropriately selected as necessary, for example, a protective layer, an intermediate layer, an undercoat layer, a cushion layer, charge control (prevention). ) Layer, reflective layer, color preparation layer, storage stability improving layer, adhesion preventing layer, anti-curl layer, smoothing layer, and the like. Each of these layers may have a single layer structure or a laminated structure.
[0010]
[Support]
Examples of the support include base paper, synthetic paper, synthetic resin sheet, coated paper, and laminated paper. These supports may have a single layer structure or a laminated structure of two or more layers.
[0011]
-Base paper-
As raw materials for the base paper, those used for known base paper as those used for the support are not particularly limited, and can be selected from various materials. For example, natural pulp selected from conifers and hardwoods, synthetic pulp made of plastic materials such as polyethylene and polypropylene, or a mixture of natural pulp and synthetic pulp can be used.
[0012]
The pulp that can be used as the raw material of the base paper is hardwood bleached kraft pulp (LBKP) from the viewpoint of improving the surface smoothness, rigidity and dimensional stability (curlability) of the base paper at the same time in a well-balanced and sufficient level. Although desirable, softwood bleached kraft pulp (NBKP), hardwood sulfite pulp (LBSP) and the like can also be used.
As the pulp fiber, it is appropriate to mainly use hardwood pulp having a short fiber length.
A beater or refiner can be used for beating the pulp. In the pulp slurry obtained after beating the pulp (hereinafter sometimes referred to as “pulp paper material”), various additives such as a filler, a dry paper strength enhancer, a sizing agent, and a wet agent are used as necessary. A paper strength enhancer, a fixing agent, a pH adjuster, and other agents are added.
[0013]
Examples of the filler include calcium carbonate, clay, kaolin, white clay, talc, titanium oxide, diatomaceous earth, barium sulfate, aluminum hydroxide, and magnesium hydroxide.
Examples of the dry paper strength enhancer include cationized starch, cationized polyacrylamide, anionized polyacrylamide, amphoteric polyacrylamide, and carboxy-modified polyvinyl alcohol.
Examples of the sizing agent include fatty acid salts, rosin derivatives such as rosin and maleated rosin, paraffin wax and the like, and higher fatty acids such as alkyl ketene dimer, alkenyl succinic anhydride (ASA) and epoxidized fatty acid amide. Examples thereof include compounds.
[0014]
Examples of the wet paper strength enhancer include polyamine polyamide epichlorohydrin, melamine resin, urea resin, and epoxidized polyamide resin.
Examples of the fixing agent include polyvalent metal salts such as aluminum sulfate and aluminum chloride, and cationic polymers such as cationized starch.
Examples of the pH adjuster include caustic soda and sodium carbonate. Examples of other chemicals include antifoaming agents, dyes, slime control agents, fluorescent whitening agents, and the like.
Moreover, a softening agent etc. can also be added as needed. The softening agent is described in, for example, New Paper Processing Handbook (edited by Paper Medicine Time), pages 554 to 555 (issued in 1980).
[0015]
The treatment liquid used for the surface sizing treatment may contain, for example, a water-soluble polymer, a sizing agent, a water-resistant substance, a pigment, a pH adjusting agent, a dye, and a fluorescent brightening agent. Examples of the water-soluble polymer include cationized starch, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose sulfate, gelatin, casein, sodium polyacrylate, styrene-maleic anhydride copolymer sodium salt, Examples thereof include sodium polystyrene sulfonate.
[0016]
Examples of the water resistant substance include latex emulsions such as styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyethylene, vinylidene chloride copolymer, and polyamide polyamine epichlorohydrin.
Examples of the pigment include calcium carbonate, clay, kaolin, talc, barium sulfate, and titanium oxide.
Examples of base paper materials include synthetic pulp paper, mixed paper of natural pulp and synthetic pulp, and various types of combined paper, in addition to the above-described natural pulp paper.
[0017]
The base paper as described above is a ratio (Ea / Eb) of the longitudinal Young's modulus (Ea) and the transverse Young's modulus (Eb) in terms of improving the rigidity and dimensional stability (curlability) of the electrophotographic image receiving paper. ) Is preferably in the range of 1.5 to 2.0. In the range where the Ea / Eb value is less than 1.5 or more than 2.0, the rigidity and curl property of the electrophotographic image-receiving paper are liable to be deteriorated, and the running property during transportation is hindered. Absent.
[0018]
In the present invention, the Oken-type smoothness of the image receiving layer side surface of the base paper is 210 seconds or more, preferably 250 seconds or more. If the Oken type smoothness is less than 210 seconds, the image quality of the toner image becomes poor, which is not preferable. The upper limit is not particularly limited, but is practically about 600 seconds, preferably about 500 seconds.
Here, the Oken smoothness is determined by JAPAN TAPPI No. 5 Smoothness specified by the B method.
[0019]
In general, it is known that paper “strain” differs based on the difference in beating style, and after beating, the elasticity (rate) of the paper made after paper beating is an important measure of the level of paper “strain”. Can be used as an additional factor. In particular, the elastic modulus of paper is measured by measuring the speed of sound propagating through the paper, using the relationship between the dynamic elastic modulus and density, which indicates the physical properties of the viscoelastic material of the paper, and using an ultrasonic vibration element. Can be obtained from the following equation.
E = ρc²(1-n²)
[E: dynamic elastic modulus, ρ: density, c: speed of sound in paper, n: Poisson's ratio]
[0020]
In the case of normal paper, since n = about 0.2, even if it is calculated by the following formula, it can be calculated without much difference.
E = ρc²
That is, if the density and sound speed of paper can be measured, the elastic modulus can be easily obtained. In the above equation, when measuring the speed of sound, various known devices such as Sonic Tester SST-110 (manufactured by Nomura Corporation) can be used.
[0021]
The thickness of the base paper is usually 30 to 500 μm, preferably 50 to 300 μm, more preferably 100 to 250 μm. The basis weight of the base paper is preferably 50 to 250 g / m, for example.², More preferably 100 to 200 g / m²It is preferable that it exists in the range.
[0022]
Specific examples of the base paper include high-quality paper and, for example, “Photographic Engineering Basics—Silver Salt Photography” edited by the Japan Photography Society, published by Corona Co., Ltd. (Showa 54) (223) to (240). The papers described are suitable.
[0023]
In order to impart a desired centerline average roughness to the surface of the base paper, for example, as disclosed in JP-A-58-68037, a fiber length distribution (for example, a 24 mesh screen residue and , 42 mesh screen residue is preferably 20% by mass to 45% by mass, and 24 mesh screen residue is preferably 5% by mass or less. Further, the center line average roughness can be adjusted by applying heat and pressure to the surface with a machine calendar, a super calendar, or the like.
[0024]
-Synthetic paper-
The synthetic paper is paper mainly composed of polymer fibers other than cellulose, and examples of the polymer fibers include polyolefin fibers such as polyethylene and polypropylene.
[0025]
-Synthetic resin sheet (film)-
Examples of the synthetic resin sheet (film) include those obtained by forming a synthetic resin into a sheet shape, such as polypropylene, stretched polyethylene, stretched polypropylene, polyester film, stretched polyester, nylon film, stretched white film, Examples thereof include a white film containing a white pigment.
[0026]
-Coated paper-
The coated paper is a paper obtained by coating various sheets of resin, rubber latex, or polymer material on one side or both sides of a sheet such as a base paper, and the coating amount varies depending on the application. Examples of such coated paper include art paper, cast coated paper, Yankee paper, and the like.
[0027]
As the resin applied to the surface of the base paper or the like, it is appropriate to use a thermoplastic resin. Examples of such a thermoplastic resin include the following thermoplastic resins (a) to (h).
[0028]
(A) Polyolefin resins such as polyethylene resins and polypropylene resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, acrylic resins, and the like.
(B) A thermoplastic resin having an ester bond. For example, a dicarboxylic acid component (these dicarboxylic acid components may be substituted with a sulfonic acid group, a carboxyl group, etc.) and an alcohol component (these alcohol components may be substituted with a hydroxyl group, etc.) Polyester resin, polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polybutyl acrylate and other polyacrylic acid ester resins or polymethacrylic acid ester resins, polycarbonate resins, polyvinyl acetate resins, styrene acrylate resins, styrene -Methacrylic acid ester copolymer resin, vinyl toluene acrylate resin, etc. are mentioned.
Specific examples include those described in JP-A Nos. 59-101395, 63-7971, 63-7972, 63-7973, and 60-294862. it can.
Commercially available products include Byron 290, Byron 200, Byron 280, Byron 300, Byron 103, Byron GK-140, Byron GK-130 manufactured by Toyobo; Kao Tufton NE-382, Tufton U-5, ATR- 2009, ATR-2010; Unitika's Elitel UE3500, UE3210, XA-8153, KZA-7049, KZA-1449; Nippon Synthetic Chemical Polyester TP-220, R-188; And various thermoplastic resins.
[0029]
(C) Polyurethane resin etc. are mentioned.
(D) Polyamide resin, urea resin, etc. are mentioned.
(E) Polysulfone resin and the like.
(F) Polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin, and the like.
(G) Cellulose resins such as polyol resins, ethyl cellulose resins, and cellulose acetate resins, such as polyvinyl butyral.
(H) Polycaprolactone resin, styrene-maleic anhydride resin, polyacrylonitrile resin, polyether resin, epoxy resin, phenol resin and the like.
In addition, the said thermoplastic resin may be used individually by 1 type, and may use 2 or more types together.
[0030]
Further, the resin may contain a brightening agent, a conductive agent, a filler, a pigment such as titanium oxide, ultramarine blue, carbon black, or a dye, if necessary.
[0031]
-Laminated paper-
The laminated paper is a paper obtained by laminating various resins, rubber or polymer sheets or films on a sheet such as a base paper. Examples of the laminate material include polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, polyimide, triacetyl cellulose, and the like. These resins may be used alone or in combination of two or more.
[0032]
In general, the polyolefin is often formed using low density polyethylene, but in order to improve the heat resistance of the support, polypropylene, a blend of polypropylene and polyethylene, high density polyethylene, high density polyethylene and low density polyethylene, It is preferable to use a blend of In particular, it is most preferable to use a blend of high-density polyethylene and low-density polyethylene from the viewpoint of cost, suitability for lamination, and the like.
[0033]
The blend of the high density polyethylene and the low density polyethylene is used, for example, in a blend ratio (mass ratio) of 1/9 to 9/1. The blend ratio is preferably 2/8 to 8/2, and more preferably 3/7 to 7/3. When forming a thermoplastic resin layer on both surfaces of the support, the back surface of the support is preferably formed using, for example, high-density polyethylene or a blend of high-density polyethylene and low-density polyethylene. The molecular weight of polyethylene is not particularly limited, but the melt index is 1.0 to 40 g / 10 min for both high-density polyethylene and low-density polyethylene and has extrudability. preferable.
In addition, you may perform the process which gives white reflectivity to these sheets or films. Examples of such a treatment method include a method of blending a pigment such as titanium oxide in these sheets or films.
[0034]
The thickness of the support is preferably 25 μm to 300 μm, more preferably 50 μm to 260 μm, and still more preferably 75 μm to 220 μm. Various types of stiffness can be used according to the purpose of the support, and the support for a photographic image receiving sheet for electrophotography is close to a support for color silver salt photography. Those are preferred.
[0035]
[Image receiving layer]
-Configuration and mode of image receiving layer-
In the present invention, the image receiving layer has a laminated structure of two or more layers. In the image receiving layer, the hardness of the layer closest to the support is not less than the hardness of the other layers. In the present invention, since the image receiving layer has such an aspect, an image having an extremely good glossiness is efficiently formed by forming an image by an image forming method in which fixing is performed by belt fixing. . Moreover, the surface deterioration due to humidity change is also effectively suppressed.
[0036]
In the image receiving layer, the melt viscosity at the fixing temperature of the resin contained in the layer closest to the support among the laminated layers is equal to or higher than the melt viscosity at the fixing temperature of the resin contained in the other layers. Is preferred.
Here, in the present invention, the “fixing temperature” is a temperature at which the image-receiving layer reaches the implementation in the toner fixing step, such as the temperature of the heating member, the conveyance speed, each material, the heat capacity of the member, the thermal conductivity, etc. It means the temperature determined according to. The fixing temperature is preferably lower than the set temperature (roller surface temperature) of the heating roller, and is preferably about set temperature to set temperature −60 ° C.
Specifically, the fixing temperature is preferably 90 to 120 ° C, more preferably 100 to 110 ° C, and still more preferably 103 to 107 ° C.
In the image receiving layer, the melt viscosity at the fixing temperature of the resin contained in the layer closest to the support among the layers is specifically the fixing temperature of the resin contained in the layer farthest from the support. The melt viscosity is preferably 3 times or more, more preferably 10 times or more.
The melt viscosity can be determined by making a resin in a molten state at a fixing temperature and measuring the viscosity or shear modulus in that state using a known melt viscosity measuring apparatus.
[0037]
In the image receiving layer, the glass transition temperature (Tg) of the resin contained in the layer closest to the support among the laminated layers is equal to or higher than the glass transition temperature (Tg) of the resin contained in the other layer. More specifically, it is preferably 1 ° C. or more higher than the glass transition temperature (Tg) of the resin contained in the layer farthest from the support among the laminated layers in the image receiving layer, and is 15 ° C. or more higher. Is more preferable.
The glass transition temperature (Tg) can be measured by, for example, a differential scanning calorimeter (DSC).
[0038]
In the image receiving layer, the flow start temperature (Ts) of the resin contained in the layer closest to the support among the stacked layers is equal to or higher than the flow start temperature (Ts) of the resin contained in the other layers. More specifically, it is preferably 1 ° C. or more higher than the flow start temperature (Ts) of the resin contained in the layer farthest from the support among the laminated layers in the image receiving layer, and is 15 ° C. or more higher. Is more preferable.
The flow start temperature (Ts) can be measured using, for example, a flow tester CFT-500 manufactured by Shimadzu Corporation.
[0039]
Moreover, in the said image receiving layer, the glass transition temperature (Tg) of resin contained in the layer nearest to the said support body among each laminated | stacked layer is preferable 80 degreeC or more, and 85 degreeC or more is more preferable.
[0040]
Further, in the image receiving layer, the layer closest to the support among the laminated layers includes a resin having a glass transition temperature (Tg) of 80 ° C. or higher and a resin having a glass transition temperature (Tg) of 25 ° C. or lower. Preferably, a resin having a glass transition temperature (Tg) of 85 ° C. or higher and a resin having a glass transition temperature (Tg) of 20 ° C. or lower are more preferable.
Content ratio of the resin having a glass transition temperature (Tg) of 80 ° C. or more and a resin having a glass transition temperature (Tg) of 25 ° C. or less (glass transition temperature (Tg) of 80 ° C. or more / glass transition temperature (Tg) of 25 ° C. or less. Resin) (mass ratio) is preferably about 5/1 to 200/1, more preferably 10/1 to 100/1.
[0041]
Furthermore, in the image receiving layer, among the laminated layers, the layer closest to the support has a glass transition temperature (Tg) of 80 ° C. or more in the core portion and a glass transition temperature (Tg) of 25 ° C. in the shell portion. It is preferable that a core / shell type resin having a core / shell content ratio (mass ratio) of 1 or more is included. In the core / shell type resin, the glass transition temperature (Tg) in the core portion is more preferably 85 ° C. or higher, and further preferably 95 ° C. or higher. In the core / shell type resin, the crow transition temperature (Tg) in the shell portion is preferably 10 ° C. or less, and more preferably 0 ° C. or less.
[0042]
Further, the image receiving layer has a multilayer structure of three or more layers, and among the laminated layers in the image receiving layer, the hardness of the layer closest to the support and the layer farthest from the support is closest to the support The hardness is preferably equal to or higher than the hardness of the layer other than the layer and the layer farthest from the support. Thus, among the laminated layers in the image receiving layer, the layer closest to the support has the highest hardness, the layer farthest from the support has the second highest hardness, and the hardness in the other intermediate layers has these layers. Thus, an electrophotographic image-receiving sheet is provided that has particularly good gloss and suppresses surface deterioration due to changes in humidity.
[0043]
Similarly, the image receiving layer has a multilayer structure of three or more layers, and the melt viscosity at the fixing temperature of the resin contained in the layer closest to the support and the layer farthest from the support is the support layer. The resin contained in a layer other than the layer closest to the body and the layer farthest from the support preferably has a melt viscosity equal to or higher than the melt viscosity at the fixing temperature. The fixing temperature is particularly preferably a fixing temperature used for image formation, specifically, 90 to 120 ° C is preferable, 100 to 110 ° C is more preferable, and 103 to 107 ° C is still more preferable.
Furthermore, similarly, the image receiving layer has a multilayer structure of three or more layers, and the flow start temperature (Ts) of the resin contained in the layer closest to the support and the layer farthest from the support in the image receiving layer is It is preferable that the temperature be equal to or higher than the flow start temperature (Ts) of the resin contained in a layer other than the layer closest to the support and the layer farthest from the support.
[0044]
In the present invention, when the image receiving layer is in these modes, as described above, an image having an extremely good glossiness is efficiently formed by forming an image by an image forming method in which fixing is performed by belt fixing. It is formed. In addition, deterioration of the surface due to humidity change can be extremely effectively suppressed.
[0045]
-Material of image receiving layer-
As described above, the image receiving layer has a laminated structure of two or more layers, and receives at least one of color toner and black toner, and is a layer on which an image is formed.
The material for the image receiving layer is preferably selected appropriately from the materials for the image receiving layer described below so that each layer has the configuration / mode described in the section “Image receiving layer configuration / mode, etc.”.
The material of the image receiving layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, in the transfer process, an image is formed from a developing drum or an intermediate transfer member by (static) electricity, pressure, or the like. Examples include receptive substances that can accept toner and can be fixed by heat, pressure, or the like in the fixing step.
Examples of the receptive substance include a thermoplastic resin, a water-soluble resin, and a colorant.
[0046]
These may be used individually by 1 type and may use 2 or more types together. Among these, a thermoplastic resin is preferable, and among these thermoplastic resins, a resin similar to the binder resin contained in the toner particles used for image formation is particularly preferable in terms of toner fixing property.
[0047]
-Thermoplastic resin-
The thermoplastic resin is not particularly limited as long as it can be deformed under temperature conditions such as fixing and can accept the toner, and can be appropriately selected according to the purpose. And the same type of resins are preferred. In many of the toners, polyester resins, copolymer resins such as styrene and styrene-butyl acrylate are used. In this case, polyester resins, styrene, styrene are also used as the thermoplastic resins used in the electrophotographic image-receiving sheet. It is preferable to use a copolymer resin (styrene-acrylic resin) such as butyl acrylate, more preferably 20% by mass or more of a polyester resin, styrene, or a copolymer resin such as styrene-butyl acrylate, Styrene-butyl acrylate copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, styrene-butadiene copolymers, butadiene resins, and the like are also preferable.
[0048]
Specific examples of the thermoplastic resin include, for example, (a) a resin having an ester bond, (b) a polyurethane resin, (c) a polyamide resin, (d) a polysulfone resin, (e) a polyvinyl chloride resin, and the like. (F) Polyvinyl butyral, (g) Polycaprolactone resin, (h) Polyolefin resin, and the like.
[0049]
Examples of the resin having an ester bond (b) include terephthalic acid, isophthalic acid, maleic acid, fumaric acid, phthalic acid, adipic acid, sebacic acid, azelaic acid, abietic acid, succinic acid, trimellitic acid, and pyromellitic acid. Dicarboxylic acid components such as acids (these dicarboxylic acid components may be substituted with sulfonic acid groups, carboxyl groups, etc.) and diether derivatives of ethylene glycol, diethylene glycol, propylene glycol, bisphenol A, bisphenol A (for example, Bisphenol A ethylene oxide 2 adduct, bisphenol A propylene oxide 2 adduct, etc.), bisphenol S, 2-ethylcyclohexyldimethanol, neopentylglycol, cyclohexyldimethanol, glycerin, etc. Polyester resins obtained by condensation with components (hydroxyl groups may be substituted on these alcohol components), polyacrylic ester resins such as polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polybutyl acrylate, etc. Examples thereof include polymethacrylate resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, styrene-methacrylate copolymer resin, vinyl toluene acrylate resin, and the like. Specifically, JP-A-59-101395 63-7971, 63-7972, 63-7973, and 60-294862, and the like.
[0050]
Commercially available products of the polyester resin include Toyobo's Byron 290, Byron 200, Byron 280, Byron 300, Byron 103, Byron GK-140, Byron GK-130; Kao's Tufton NE-382, Tufton U-5, ATR-2009, ATR-2010; Elitel UE3500, UE3210, XA-8153 manufactured by Unitika; Polyester TP-220, R-188 manufactured by Nippon Synthetic Chemical Co., Ltd. and the like. Dianal SE-5437, SE-5102, SE-5377, SE-5649, SE-5466, SE-5482, HR-169, 124, HR-1127, HR-116, HR-113, HR- 148, HR-131, HR-470, HR-63 , HR-606, HR-607, LR-1065, 574, 143, 396, 637, 162, 469, 216, BR-50, BR-52, BR-60, BR-64, BR-73, BR-75 , BR-77, BR-79, BR-80, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR -102, BR-105, BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117; Sekisui Chemical Co., Ltd. ESREC P SE-0020, SE -0040, SE-0070, SE-0100, SE-1010, SE-1035; Sanyo Chemical Industries Himer ST95, ST120, Mitsui Chemicals' FM601, and the like.
[0051]
Examples of the (v) polyvinyl chloride resin further include polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin, and the like.
Examples of the (f) polyvinyl butyral include cellulose resins such as polyol resins, ethyl cellulose resins, and cellulose acetate resins. Commercial products include those manufactured by Denki Kagaku Kogyo Co., Ltd. and Sekisui Chemical Co., Ltd. Can be mentioned. The polyvinyl butyral has a polyvinyl butyral content of 70% by mass or more, an average polymerization degree of 500 or more is preferable, an average polymerization degree of 1000 or more is more preferable, and a commercially available product is Denka Butyral manufactured by Denki Kagaku Kogyo Co. 3000-1, 4000-2, 5000A, 6000C; manufactured by Sekisui Chemical Co., Ltd. S-REC BL-1, BL-2, BL-3, BL-S, BX-L, BM-1, BM-2, BM-5 , BM-S, BH-3, BX-1, BX-7, and the like.
Examples of the (g) polycaprolactone resin include styrene-maleic anhydride resin, polyacrylonitrile resin, polyether resin, epoxy resin, phenol resin, and the like.
Examples of the (h) polyolefin resin include polyethylene resins, polypropylene resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, acrylic resins, and the like.
[0052]
The said thermoplastic resin may be used individually by 1 type, may be 2 or more types, In addition to these, these mixtures, these copolymers, etc. can also be used.
[0053]
The thermoplastic resin is preferably one that can satisfy the above-mentioned image receiving layer physical properties in the state where the image receiving layer is formed, more preferably one that can satisfy the above-mentioned image receiving layer physical properties even with a resin alone, and has different image receiving layer physical properties. It is also preferable to use two or more resins in combination.
[0054]
As the thermoplastic resin, those having a larger molecular weight than the thermoplastic resin used in the toner are preferable. However, the molecular weight described above is not necessarily preferable depending on the relationship between the thermodynamic characteristics of the thermoplastic resin used in the toner and the resin used in the image receiving layer. For example, when the softening temperature of the resin used in the image receiving layer is higher than the thermoplastic resin used in the toner, the molecular weight is the same or the resin used in the image receiving layer is smaller. May be preferred.
[0055]
It is also preferable to use a mixture of resins having the same composition and different average molecular weights as the thermoplastic resin. Further, as the relationship with the molecular weight of the thermoplastic resin used in the toner, the relationship disclosed in JP-A-8-334915 is preferable.
The molecular weight distribution of the thermoplastic resin is preferably wider than the molecular weight distribution of the thermoplastic resin used in the toner.
Examples of the thermoplastic resin include Japanese Patent Publication No. 5-127413, No. 8-194394, No. 8-334915, No. 8-334916, No. 9-171265, No. 10-221877, and the like. Those satisfying the physical properties disclosed in 1) are preferred.
[0056]
-Water-soluble resin-
The water-soluble resin is not particularly limited as long as it is a water-soluble resin, and the composition, bond structure, molecular structure, molecular weight, molecular weight distribution, form and the like can be appropriately selected depending on the purpose. And those having a water-solubilizing group.
Examples of the water-solubilizing group of the polymer include a sulfonic acid group, a hydroxyl group, a carboxylic acid group, an amino group, an amide group, and an ether group.
[0057]
Examples of the water-soluble resin include Research Disclosure No. 17,643, page 26, 18,716, page 651, 307,105, pages 873-874, and JP-A No. 64-13,546 (71). ) To (75), specifically, for example, vinylpyrrolidone-vinyl acetate copolymer, styrene-vinylpyrrolidone copolymer, styrene-maleic anhydride copolymer, water-soluble Water-soluble polyester, water-soluble polyurethane, water-soluble nylon, water-soluble epoxy resin, and the like.
[0058]
As the water-soluble resin, when the binder resin of the toner is a polyester resin or the like, a water-dispersed polyester or the like can be suitably used as the resin for the image receiving layer.
[0059]
Other examples of the water-soluble resin include water-dispersed resins such as water-dispersed acrylic resins, water-dispersed polyester resins, water-dispersed polystyrene resins, and water-dispersed urethane resins; acrylic resin emulsions, polyvinyl acetate emulsions, SBR (styrene- Examples thereof include emulsions such as butadiene and rubber emulsions, resins and emulsions in which the thermoplastic resin is dispersed in water, or copolymers, mixtures, and cation-modified products thereof.
These may be used alone or in combination of two or more.
[0060]
Commercially available products of the water-dispersed resin include, for example, Toyobo Vylonal MD-1200, MD-1220, MD-1930; Kyoyo Chemical Plus Coat Z-446, Z-465, RZ-96; Dainippon Ink ES- 611, ES-670; Pesresin A-160P, A-210, A-620 made by Takamatsu Yushi; Hiros XE-18, XE-35, XE-48, XE-60, XE-62 made by Seiko Chemical Industry; Jurimer AT-210, AT-510, AT-515, AT-613, ET-410, ET-530, ET-533, FC-60, FC-80, etc. are mentioned.
[0061]
As the water-soluble resin, gelatin is preferably mentioned, and the gelatin is selected from so-called demineralized gelatin in which the content of lime-processed gelatin, acid-processed gelatin, calcium, etc. is reduced according to various purposes. Well, you may use these together.
[0062]
In the present invention, it is preferable to use a self-dispersing water-based polyester resin emulsion that satisfies the following characteristics (1) to (4) as the thermoplastic resin. Since this is a self-dispersion type that does not use a surfactant, it has low hygroscopicity even in a high humidity atmosphere, and there is little decrease in the softening point due to moisture, and it is possible to suppress occurrence of offset at the time of fixing and adhesion failure between sheets at the time of storage. Moreover, since it is water-based, it is excellent in environmental performance and workability. In addition, since a polyester resin with a high cohesive energy and a molecular structure is used, it has a sufficient hardness in the storage environment, but it becomes a low elasticity (low viscosity) molten state in the electrophotographic fixing process, and the toner receives an image. Sufficient image quality can be achieved by embedding in the layer.
(1) The number average molecular weight (Mn) is preferably 5,000 to 10,000, and more preferably 5,000 to 7,000.
(2) The molecular weight distribution (mass average molecular weight / number average molecular weight) is preferably ≦ 4, more preferably Mw / Mn ≦ 3.
(3) The glass transition temperature (Tg) is preferably 40 to 100 ° C, more preferably 50 to 80 ° C.
(4) The volume average particle diameter is preferably 20 to 200 nmφ, more preferably 40 to 150 mmφ.
[0063]
The film-forming temperature of the water-soluble resin is preferably room temperature or higher for storage before printing, and preferably 100 ° C. or lower for fixing toner particles.
[0064]
In the image receiving layer, when the layer closest to the support among the laminated layers includes the core / shell type resin, examples of the core / shell type resin include polystyrene (core) / modified styrene-butadiene ( Shell) resin, styrene-acrylic resin, polystyrene (core) / modified NBR resin, and the like.
[0065]
-Colorant-
Examples of the colorant include fluorescent whitening agents, white pigments, colored pigments, and dyes.
The fluorescent whitening agent is a compound that absorbs in the near ultraviolet region and emits fluorescence at 400 to 500 nm, and various known fluorescent whitening agents can be used without particular limitation. Examples of the optical brightener include K.I. Preferable examples include compounds described in “The Chemistry of Synthetic Dies” V, Chapter 8 edited by Veen Rataraman. Specific examples include stilbene compounds, coumarin compounds, biphenyl compounds, benzoxazoline compounds, naphthalimide compounds, pyrazoline compounds, carbostyryl compounds, and the like. Examples thereof include white fur fur PSN, PHR, HCS, PCS, B manufactured by Sumitomo Chemical; UVITEX-OB manufactured by Ciba-Geigy.
[0066]
As the white pigment, inorganic pigments described in the filler section (for example, titanium oxide, calcium carbonate, etc.) can be used. Examples of colored pigments include various pigments and azo pigments described in JP-A-63-44653 (for example, azo lake; carmine 6B, red 2B, insoluble azo; monoazo yellow, disazo yellow, pyrazolo orange, vulcan orange, condensation) Azo series; chromophthal yellow, chromophthal red), polycyclic pigments (for example, phthalocyanine series; copper phthalocyanine blue, copper phthalocyanine green, dioxazine series; dioxazine violet, isoindolinone series; isoindolinone yellow, slen series; Perylene, perinone, flavantron, thioindigo, lake pigment (eg, malachite green, rhodamine B, rhodamine G, Victoria blue B) or inorganic pigment (eg, oxide, titanium dioxide, bengara, sulfate; precipitated barium sulfate) Calcium precipitated carbonates, silicates; carbonates hydrous silicates, anhydrous silicates, metal powders; aluminum powder, bronze powder, zinc powder, carbon black, chrome yellow, Prussian blue and the like.
These may be used alone or in combination of two or more. Among these, titanium oxide is particularly preferable as the pigment.
[0067]
Although there is no restriction | limiting in particular as a shape of the said pigment, It is preferable that it is a hollow particle shape at the point which is excellent in the heat conductivity at the time of image fixing (low heat conductivity).
[0068]
Various known dyes can be used as the dye.
Examples of oil-soluble dyes include anthraquinone compounds and azo compounds.
Specific examples of water-insoluble dyes include C.I. I. Vat violet 1, C.I. I. Vat violet 2, C.I. I. Vat violet 9, C.I. I. Vat violet 13, C.I. I. Vat violet 21, C.I. I. Vat Blue 1, C.I. I. Vat Blue 3, C.I. I. Vat Blue 4, C.I. I. Vat Blue 6, C.I. I. Vat Blue 14, C.I. I. Vat Blue 20, C.I. I. Vat dyes such as Vat Blue 35, C.I. I. Dispers Violet 1, C.I. I. Disperse Violet 4, C.I. I. Disperse Violet 10, C.I. I. Disperse Blue 3, C.I. I. Disperse Blue 7, C.I. I. Disperse dyes such as Disperse Blue 58, C.I. I. Solvent Violet 13, C.I. I. Solvent Violet 14, C.I. I. Solvent Violet 21, C.I. I. Solvent Violet 27, C.I. I. Solvent Blue 11, C.I. I. Solvent Blue 12, C.I. I. Solvent Blue 25, C.I. I. Examples thereof include oil-soluble dyes such as Solvent Blue 55.
[0069]
Further, a colored coupler used in silver salt photography can also be preferably used.
[0070]
Content of the colorant in the image receiving layer (surface) (g / m²) As 0.1 to 8 g / m²Is preferably 0.5 to 5 g / m²Is more preferable.
The content of the colorant is 0.1 g / m²If it is less than 1, the light transmittance in the image-receiving layer becomes high, while the content of the colorant is 8 g / m.²Exceeding may cause poor handling such as cracking and adhesion resistance.
[0071]
-Other ingredients-
Examples of the other components include various additives added for the purpose of improving the thermodynamic properties of the image receiving layer, such as a mold release agent, a plasticizer, a filler, a crosslinking agent, a charge control agent, an emulsion, a dispersion, and the like. Is mentioned.
[0072]
--- Mold release agent--
The release agent of the present invention is blended in the image receiving layer in order to prevent the image receiving layer from being offset. The release agent used in the present invention is heated and melted at the fixing temperature, deposited on the surface of the image receiving layer, unevenly distributed on the surface of the image receiving layer, and further cooled and solidified to be released onto the surface of the image receiving layer. The type is not limited as long as the layer is formed.
Examples of the release agent exhibiting such effects include at least one release agent selected from the group consisting of silicone compounds, fluorine compounds, waxes, and matting agents. Preferably, at least one release agent selected from the group consisting of silicone oil, polyethylene wax, carnauba wax, and silicone particles and polyethylene wax particles is used.
[0073]
Specifically, as the release agent used in the present invention, for example, compounds described in “Summary of the properties and applications of revised wax” and the Silicone Handbook published by Nikkan Kogyo Shimbun can be used. JP-B-59-38581, JP-B-4-32380, Patent Nos. 2838498, 2949558, JP-A-50-117433, 52-52640, 57-148755, 61-62056. 61-62057, 61-118760, JP-A-2-42451, 3-41465, 4-212175, 4-214570, 4-263267, 5-34966, 5-119514, 6-59502, 6-161150, 6-175396, 6-219040, 6-230600, 6-295093, 7-36210, 7 -43940, 7-56387, 7-56390, 7-64335, 7-199682, 7-223362 7-287413, 8-184992, 8-227180, 8-248671, 8-248799, 8-248801, 8-278663, 9-152939, 9 -160278, 9-185181, 9-319139, 9-319143, 10-20549, 10-48889, 10-198069, 10-207116, 11-2917 No. 11-44969, No. 11-65156, No. 11-73049, No. 11-194542, and the silicone compounds, fluorine compounds, and waxes used in the toners are also preferably used. . A plurality of these compounds can be used in combination.
[0074]
Specifically, as the silicone compound, unmodified silicone oil as silicone oil (specifically, dimethylsiloxane oil, methyl hydrogen silicone oil, phenylmethyl silicone oil, commercially available KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.) KF-96L, KF-96H, KF-99, KF-50, KF-54, KF-56, KF-965, KF-968, KF-994, KF-995, HIVAC F-4, F-5; Toray Dow Corning Silicone SH200, SH203, SH490, SH510, SH550, SH710, SH704, SH705, SH7028A, SH7036, SM7060, SM7001, SM7706, SH7036, SH8710, SH1107, SH8627; Toshiba Silicone TSF400, TSF401, TSF404, TSF405, TSF431, TSF433, TSF434, TSF437, TSF450 series, TSF451 series, TSF456, TSF458 series, TSF483, TSF484, TSF4045, TSF4300, TSF4600, YF33 series, YF-3057, YF-3057 3802, YF-3804, YF-3807, YF-3897, XF-3905, XS69-A1753, TEX100, TEX101, TEX102, TEX103, TEX104, TSW831, etc., amino-modified silicone oil (KF manufactured by Shin-Etsu Chemical Co., Ltd. as a commercial product) -857, KF-858, KF-859, KF-861, KF-864, KF-880, Toray Dowco SF8417, SM8709 made by Ning Silicone, TSF4700, TSF4701, TSF4702, TSF4703, TSF4704, TSF4705, TSF4706, TEX150, TEX151, TEX154, etc. made by Toshiba Silicone, carboxy-modified silicone oil (Toray Dow Corning Silicone BY16- as a commercial product) 880, Toshiba Silicone TSF4770, XF42-A9248, etc.), Carbinol-modified silicone oil (Toshiba Silicone XF42-B0970 etc. as a commercial product), Vinyl-modified silicone oil (Toshiba Silicone XF40-A1987 etc. as a commercial product), epoxy modification Silicone oil (Toray Dow Corning Silicone SF8411, SF8413 as a commercial product; Toshiba Silico TSF3965, TSF4730, TSF4732, XF42-A4439, XF42-A4438, XF42-A5041, XC96-A4462, XC96-A4463, XC96-A4464, TEX170, etc., polyether-modified silicone oil (manufactured by Shin-Etsu Chemical) KF-351 (A), KF-352 (A), KF-353 (A), KF-354 (A), KF-355 (A), KF-615 (A), KF-618, KF-945 ( A); Toray Dow Corning Silicone SH3746, SH3771, SF8421, SF8419, SH8400, SF8410; Toshiba Silicone TSF4440, TSF4441, TSF4445, TSF4446, TSF4450, TSF4452, TSF4453, SF4460), silanol-modified silicone oil, methacryl-modified silicone oil, mercapto-modified silicone oil, alcohol-modified silicone oil (Toray Dow Corning Silicone SF8427, SF8428, Toshiba Silicone TSF4750, TSF4751, XF42-B0970, etc.) , Alkyl-modified silicone oil (SF8416 made by Toray Dow Corning Silicone, TSF410, TSF411, TSF4420, TSF4421, TSF4422, TSF4450, XF42-334, XF42-A3160, XF42-A3161, etc. made by Toshiba Silicone) Oil (commercially available FS1265 made by Toray Dow Corning Silicone, Toshiba Silicon Corporation FQF501, etc.), silicone rubber and silicone fine particles (Toray Dow Corning Silicone SH851U, SH745U, SH55UA, SE4705U, SH502UA & B, SRX539U, SE6770U-P, DY38-038, DY38-047, Trefill F-201, F-202, F-250, R-900, R-902A, E-500, E-600, E-601, E-506, BY29-119; Toshiba Silicone Tospearl 105, 120, 130, 145, 240, 3120), silicone-modified resins (specifically, olefin resins, polyester resins, vinyl resins, polyamide resins, cellulose resins, phenoxy resins, vinyl chloride-vinyl acetate resins, urethane resins, acrylic resins, styrene resins). Commercially available products such as Kuryl resin and compounds obtained by modifying these copolymer resins with silicone, Dainippon Dialomer SP203V, SP712, SP2105, SP3023; Nippon Oil & Fats Modiper FS700, FS710, FS720, FS730, FS770; Cymac US-270, US-350, US-352, US-380, US-413, US-450, Reseda GP-705, GS-30, GF-150, GF-300; SH997 manufactured by Toray Dow Corning Silicone SR2114, SH2104, SR2115, SR2202, DCI-2577, SR2317, SE4001U, SRX625B, SRX643, SRX439U, SRX488U, SH804, SH840, SR2107, SR2115; YR3370, TSR1122, TSR102, TSR108, TSR116, TSR117, TSR125A, TSR127B, TSR144, TSR180, TSR187, YR47, YR3187, YR3224, YR3232, YR3270, YR3340, TE2173, TE2 , Reactive silicone compounds (specifically, there are addition reaction type, peroxide curable type, ultraviolet curable type, and TSR1500, TSR1510, TSR1511, TSR1515, TSR1520, YR3286, YR3340, PSA6574, manufactured by Toshiba Silicones as commercially available products. TPR6500, TPR6501, TPR6600, TPR6702, TPR6604, T R6700, TPR6701, TPR6705, TPR6707, TPR6708, TPR6710, TPR6712, TPR6721, TPR6722, UV9300, UV9315, UV9425, UV9430, XS56-A2775, XS56-A2982, XS56-A3075, XS56-A3957, XS56S30X80 XS56-B1794, SL6100, SM3000, SM3030, SM3200, YSR3022, etc.).
[0075]
Examples of the fluorine compound include fluorine oil (Daikin Industries # 1, # 3, # 10, # 20, # 50, # 100, Unidyne TG-440, TG-452, TG-490, TG-560 as commercial products. TG-561, TG-590, TG-652, TG-670U, TG-991, TG-999, TG-3010, TG-3020, TG-3510; TF-100, MF-110, MF manufactured by Tochem Products -120, MF-130, MF-160, MF-160E; Asahi Glass Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145; FC-430, FC-431 made by Mitsui Fluorochemical, etc.), fluoro rubber (LS63U made by Toray Dow Corning Silicone as a commercial product) Fluorine-modified resin (Nippon Yushi Modiper F200, F220, F600, F2020, F3035; Dainippon Chemical Dialomer FF203, FF204; Asahi Glass Surflon S-381, S-383, S-393, SC- 101, SC-105, KH-40, SA-100; EF-351, EF-352, EF-801, EF-802, EF-601, TFE, TFEA, TFEMA, PDFOH manufactured by Tochem Products; THV manufactured by Sumitomo 3M -200P, etc.), fluorine sulfonic acid compounds (commercially available products EF-101, EF-102, EF-103, EF-104, EF-105, EF-112, EF-121, EF-122A, EF manufactured by Tochem Products) -122B, EF-122C, EF-123A, EF-123B, E -125M, EF-132, EF-135M, EF-305, FBSA, KFBS, LFBS, etc., fluorosulfonic acid, fluorinated acid compounds and salts (specifically, hydrofluoric acid, dilute hydrofluoric acid, borofluoric acid, borofluoride) Zinc, nickel borofluoride, tin borofluoride, lead borofluoride, copper borofluoride, silicic acid, potassium fluoride titanate, perfluorocaprylic acid, ammonium perfluorooctanoate, etc., inorganic fluoride (specifically fluoride) Aluminum, potassium silicofluoride, potassium fluoride zirconate, zinc fluoride tetrahydrate, calcium fluoride, lithium fluoride, barium fluoride, tin fluoride, potassium fluoride, acidic potassium fluoride, magnesium fluoride, fluoride Titanic acid, zirconic fluoride, ammonium hexafluorophosphate, potassium hexafluorophosphate Etc.).
[0076]
Examples of the wax include petroleum wax, paraffin wax (paraffin wax 155, 150, 140, 135, 130, 125, 120, 115, HNP-3, HNP-5, HNP-9, and HNP as commercially available products). -10, HNP-11, HNP-12, HNP-14G, SP-0160, SP-0145, SP-1040, SP-1035, SP-3040, SP-3035, NPS-8070, NPS-L-70, OX -1511, OX-2251, EMUSTAR-0384, EMUSTAR-0136; Chukyo Oil & Fats Cellosol 686, 428, 651-A, A, H-803, B-460, E-172, 866, K-133, Hydrin D- 337, E-139; 125 ° paraffin, 125 ° FD, manufactured by Mitsubishi Oil Corporation 30 ° paraffin, 135 ° paraffin, 135 ° H, 140 ° paraffin, 140 ° N, 145 ° paraffin, paraffin wax M, etc.); Microcrystalline wax (Nippon Seiki Hi-Mic-2095, Hi-Mic as commercially available products) -3090, Hi-Mic-1080, Hi-Mic-1070, Hi-Mic-2065, Hi-Mic-1045, Hi-Mic-2045, EMUSTAR-0001, EMUSTAR-042X; Chukyo Oil Serosol 967, M; 155 microwax, 180 microwax, etc. manufactured by Ishi Mitsubishi Petrochemical Co., Ltd.), Petrolatum (commercially available products manufactured by Nippon Seiki OX-1749, OX-0450, OX-0650B, OX-0153, OX-261BN, OX-0551, OX-0550 , OX-0750B JP-1500, JP-056R, such as JP-011P); Fischer-Tropsch wax (as a commercial product, manufactured by Nippon Seiro Co., Ltd. FT100, FT-0070, etc.), and the like. Acid amide compound or acid imide compound (specifically, stearamide, phthalic anhydride, etc., commercially available products such as Chukyo Yushi Cellosol 920, B-495, Hymicron G-270, G-110, Hydrin D-757) Etc.), amine-modified polypropylene as a modified wax (QN-7700 manufactured by Sanyo Kasei as a commercial product), acrylic acid-modified or fluorine-modified, olefin-modified wax, urethane type wax (NPS-6010, Nippon Seiki NPS-6010, HAD-5090 as commercial products) Etc.), alcohol type waxes (NPS-9210, NPS-9215, OX-1949, XO-020T, etc., manufactured by Nippon Seiki) and the like.
Hardened castor oil (such as Ito Oil's castor wax) as a hydrogenated wax, castor oil derivatives (dehydrated castor oil DCO, DCO Z-1, DCO Z-3, castor oil fatty acid CO-FA manufactured by Ito Oil as commercial products) , Ricinoleic acid, dehydrated castor oil fatty acid DCO-FA, dehydrated castor oil fatty acid epoxy ester D-4 ester, castor oil-based urethane acrylate CA-10, CA-20, CA-30, castor oil derivative MINERASOL S-74, S- 80, S-203, S-42X, S-321, Special castor oil-based condensed fatty acid MINERASOL RC-2, RC-17, RC-55, RC-335, Special castor oil-based condensed fatty acid ester MINERASOL LB-601, LB -603, LB-604, LB-702, LB-703, 11, L-164, etc.), stearic acid (12-hydroxystearic acid made by Ito Oil as a commercial product), lauric acid, myristic acid, palmitic acid, behenic acid, sebacic acid (Sebacin made by Ito Oil as a commercial product) Acid, etc.), undecylenic acid (commercially available from Ito Oil undecylenic acid, etc.), heptylic acid (commercially available from Ito Oil heptyl acid, etc.), maleic acid, highly maleated oil (commercially available from Imade Oil's HIMALIN DC-15, LN-10, 00-15, DF-20, SF-20, etc.), blown oil (commercially available products such as Celbonol # 10, # 30, # 60, R-40, S-7 manufactured by Ito Oil) ) And synthetic waxes such as cyclopentadiene oil (commercially available products such as CP oil and CP oil-S made by Ito Oil).
[0077]
The natural wax is preferably at least one of a plant wax and a mineral wax, and particularly preferably a plant wax. The natural wax is particularly preferably a water-dispersed wax from the viewpoint of compatibility when a water-based thermoplastic resin is used as the thermoplastic resin of the image receiving layer.
[0078]
Examples of the plant wax include carnauba wax (Nippon Seiki EMUSTAR-0413, Chukyo Yushi Cellosol 524, etc. as commercial products), castor oil (commercially available Ito Oil refined castor oil, etc.), rapeseed oil, large Examples include soybean oil, wax, cotton wax, rice wax, sugarcane wax, candelilla wax, Japan wax, jojoba oil, and animal waxes such as beeswax, lanolin, spermaceti, stew wax (whale oil), and wool wax. Among these, in particular, it has an excellent offset resistance, adhesion resistance, paper permeability, glossiness, is resistant to cracking, and can provide an electrophotographic image-receiving sheet capable of forming a high-quality image. Is particularly preferably a carnauba wax having a temperature of 70 to 95 ° C.
[0079]
Examples of the mineral wax include natural waxes such as montan wax, montan ester wax, ozokerite, and ceresin, and fatty acid esters (commercially available products such as Sansizer DOA, AN-800, DINA, DIDA, DOZ, manufactured by Shin Nippon Chemical Co., Ltd.) DOS, TOTM, TITM, E-PS, nE-PS, E-PO, E-4030, E-6000, E-2000H, E-9000H, TCP, C-1100, etc.) Polyethylene wax (commercially available) Chukyo Yushi Polylon A, 393, H-481; Sanyo Kasei Sun Wax E-310, E-330, E-250P, LEL-250, LEL-800, LEL-400P, etc.), polypropylene wax (commercially available products) Sanyo Chemical Co., Ltd. Biscol 330-P, 550-P, 60-P), and the like. Among these, in particular, it has an excellent offset resistance, adhesion resistance, paper permeability, glossiness, is resistant to cracking, and can provide an electrophotographic image-receiving sheet capable of forming a high-quality image. Is particularly preferably a montan wax having a temperature of 70 to 95 ° C.
[0080]
Content (g / m) of the natural wax in the image receiving layer (surface)²) As 0.1 to 4 g / m²Is preferably 0.2 to 2 g / m²Is preferred.
The content is 0.1 g / m²If it is less than 4 g / m, the offset resistance and adhesion resistance may be particularly insufficient.²If it exceeds 1, the amount of wax is too large, and the image quality of the formed image may be inferior.
[0081]
The melting point (° C.) of the natural wax is preferably 70 to 95 ° C., more preferably 75 to 90 ° C., particularly in terms of offset resistance and paper passing properties.
[0082]
Examples of the matting agent include various known ones. Solid particles used as a matting agent can be classified into inorganic particles and organic particles. Specific examples of the material for the inorganic matting agent include oxides (for example, silicon dioxide, titanium oxide, magnesium oxide, aluminum oxide), alkaline earth metal salts (for example, barium sulfate, calcium carbonate, magnesium sulfate), halogens Examples include silver halide (eg, silver chloride, silver bromide) and glass.
[0083]
Examples of the inorganic matting agent include West German Patent 2529321, British Patent 760775, 1260772, U.S. Patent 1201905, 2192241, 3030562, 3030649, 3257206, 3322555, and 3353958. No. 3,370,951, No. 3,411,907, No. 3,437,484, No. 3523022, No. 3,615,554, No. 3,635,714, No. 3769020, No. 40212245, and No. 4029504.
[0084]
The material of the organic matting agent includes starch, cellulose ester (for example, cellulose acetate propionate), cellulose ether (for example, ethyl cellulose) and synthetic resin. The synthetic resin is preferably water-insoluble or poorly water-soluble. Examples of water-insoluble or poorly water-soluble synthetic resins include poly (meth) acrylic acid esters (for example, polyalkyl (meth) acrylate, polyalkoxyalkyl (meth) acrylate, polyglycidyl (meth) acrylate), poly (meth) Includes acrylamide, polyvinyl ester (eg, polyvinyl acetate), polyacrylonitrile, polyolefin (eg, polyethylene), polystyrene, benzoguanamine resin, formaldehyde condensation polymer, epoxy resin, polyamide, polycarbonate, phenol resin, polyvinyl carbazole and polyvinylidene chloride .
You may use the copolymer which combined the monomer used for the above polymer.
[0085]
In the case of the copolymer, a small amount of hydrophilic repeating units may be contained. Examples of the monomer forming the hydrophilic repeating unit include acrylic acid, methacrylic acid, α, β-unsaturated dicarboxylic acid, hydroxyalkyl (meth) acrylate, sulfoalkyl (meth) acrylate and styrene sulfonic acid.
Examples of the organic matting agent include British Patent No. 1055713, U.S. Patent No. 1,939,213, No. 2221873, No. 2,268,662, No. 2322037, No. Nos. 3,262,782, 3,443,946, 3,516,832, 3,539,344, 3,591,379, 3,754,924, 3,767,448, JP-A-49-106821, JP-A-57-14835 What has been described.
Two or more kinds of solid particles may be used in combination. The average particle size of the solid particles is, for example, 1 to 100 μm, preferably 4 to 30 μm. The amount of solid particles used is 0.01 to 0.5 g / m.², Preferably 0.02 to 0.3 g / m²It is appropriate that
[0086]
As the release agent added to the image receiving layer of the present invention, these derivatives, oxides, purified products, and mixtures can also be used. Moreover, these may have a reactive substituent.
[0087]
The melting point (° C.) of the release agent is preferably 70 to 95 ° C., and more preferably 75 to 90 ° C., particularly in terms of offset resistance and paper passing properties.
The release agent is particularly preferably a water-dispersed release agent from the viewpoint of compatibility when an aqueous thermoplastic resin is used as the thermoplastic resin of the image receiving layer.
[0088]
As content in the said image receiving layer of the said mold release agent, 0.1-10 mass% is preferable, 0.3-8.0 mass% is more preferable, 0.5-5.0 mass% is still more preferable. .
[0089]
--Plasticizer--
As the plasticizer, known plasticizers for resins can be used without particular limitation. The plasticizer has a function of adjusting the flow or softening of the image receiving layer by heat and / or pressure when fixing the toner.
Examples of the plasticizer include “Chemical Handbook” (edited by the Chemical Society of Japan, Maruzen), “Plasticizer—its theory and application” (written by Koichi Murai, Koshobo), “Plasticizer Research”, “Plasticizer”. "Research under" (edited by Polymer Chemistry Association) and "Handbook: Rubber / Plastic Compounded Chemicals" (edited by Rubber Digest Co., Ltd.).
[0090]
Some of the plasticizers are described as high-boiling organic solvents and thermal solvents. For example, JP-A-59-83154, 59-178451, 59-178453, and 59-178454. 59-178455, 59-178457, 62-174754, 62-245253, 61-209444, 61-200538, 62-8145, 62-9348, 62-30247, 62-136646, 62-174754, 62-245253, 61-209444, 61-200538, 62-8145, 62-9348, 62- No. 30247, 62-136646, JP-A-2-235694, and the like (for example, Tarates, phosphates, fatty acid esters, abietic acid esters, adipic acid esters, sebacic acid esters, azelaic acid esters, benzoic acid esters, butyric acid esters, epoxidized fatty acid esters, glycols Acid esters, propionic acid esters, trimellitic acid esters, citric acid esters, sulfonic acid esters, carboxylic acid esters, succinic acid esters, maleic acid esters, fumaric acid esters, phthalic acid esters, Stearic acid esters), amides (for example, fatty acid amides, sulfoamides, etc.), ethers, alcohols, lactones, polyethyleneoxy compounds, and the like.
The plasticizer can be used by mixing with a resin.
[0091]
A relatively low molecular weight polymer can be used as the plasticizer. In this case, the molecular weight of the plasticizer is preferably lower than the molecular weight of the binder resin to be plasticized, and the molecular weight is 15000 or less, preferably 5000 or less. In the case of a polymer plasticizer, the polymer is preferably the same type as the binder resin to be plasticized. For example, a low molecular weight polyester is preferable for plasticizing a polyester resin. Furthermore, oligomers can also be used as plasticizers. In addition to the compounds listed above, commercially available products include, for example, Adeka Sizer PN-170, PN-1430 manufactured by Asahi Denka Kogyo; P. HALL products PARAPLEX-G-25, G-30, G-40; Rika Hercules products Ester gum 8L-JA, Ester R-95, Pentaline 4851, FK115, 4820, 830, Louisol 28-JA, Picolastic A75, Pico Examples include Tex LC and Crystallex 3085.
[0092]
The plasticizer relieves stress and strain (physical strain such as elastic force and viscosity, strain due to material balance of molecules, binder main chain, pendant portion, etc.) generated when toner particles are embedded in the image receiving layer. Can be used arbitrarily.
The plasticizer may be in a micro-dispersed state in the image-receiving layer, in a micro-phase-separated state in a sea-island shape, or in a state sufficiently mixed and dissolved with other components such as a binder.
As content in the said image receiving layer of the said plasticizer, 0.001-90 mass% is preferable, 0.1-60 mass% is more preferable, 1-40 mass% is still more preferable.
The plasticizer adjusts smoothness (improves transportability due to reduced frictional force), improves fixing unit offset (detachment of toner and layers from the fixing unit), adjusts curl balance, and adjusts charging (toner electrostatic image It may be used for the purpose of forming).
[0093]
--Filler--
As said filler, an organic or inorganic filler is mentioned, A well-known thing can be used as a reinforcing agent for binder resin, a filler, and a reinforcing material. The filler should be selected with reference to “Handbook: Rubber / Plastic Compounding Chemicals” (edited by Rubber Digest Co., Ltd.), “New Edition: Plastic Compounding Agents Fundamentals and Applications” (Taisei), “Filler Handbook” (Taisei) Can do.
Moreover, various inorganic fillers (or pigments) can be used as the filler. Examples of the inorganic pigment include silica, alumina, titanium dioxide, zinc oxide, zirconium oxide, mica-like iron oxide, white lead, lead oxide, cobalt oxide, strontium chromate, molybdenum pigment, smectite, magnesium oxide, calcium oxide, carbonic acid Examples include calcium and mullite. As the filler, silica and alumina are particularly preferable. These fillers may be used alone or in combination of two or more. The filler preferably has a small particle size. When the particle size is large, the surface of the image receiving layer is easily roughened.
[0094]
The silica includes spherical silica and amorphous silica. The silica can be synthesized by a dry method, a wet method, or an airgel method. The surface of the hydrophobic silica particles may be surface-treated with a trimethylsilyl group or silicone. As silica, colloidal silica is preferable. As an average particle diameter of a silica, 4-120 nm is preferable and 4-90 nm is more preferable.
The silica is preferably porous. The average pore diameter of the porous silica is preferably 50 to 500 nm. Moreover, the average pore volume per mass of the porous silica is preferably, for example, 0.5 to 3 ml / g.
[0095]
The alumina includes anhydrous alumina and alumina hydrate. As the crystal form of anhydrous alumina, α, β, γ, δ, ζ, η, θ, κ, ρ, or χ can be used. Alumina hydrate is preferred over anhydrous alumina. As the alumina hydrate, a monohydrate or a trihydrate can be used. Monohydrates include pseudoboehmite, boehmite and diaspore. Trihydrates include dibsite and bayerite. As an average particle diameter of an alumina, 4-300 nm is preferable and 4-200 nm is more preferable. Alumina is preferably porous. The average pore diameter of the porous alumina is preferably 50 to 500 nm. The average pore volume per mass of the porous alumina is preferably about 0.3 to 3 ml / g.
[0096]
The alumina hydrate can be synthesized by a sol-gel method in which ammonia is added to an aluminum salt solution to precipitate or a method in which an alkali aluminate is hydrolyzed. Anhydrous alumina can be obtained by dehydrating alumina hydrate by heating.
It is preferable that the said filler is 5-2000 mass% based on the dry mass of the binder of the layer to add.
[0097]
-Crosslinking agent-
The crosslinking agent can be blended in order to adjust the storage stability of the image receiving layer, thermoplasticity, and the like. As such a crosslinking agent, an epoxy group as a reactive group, an isocyanate group, an aldehyde group, an active halogen group, an active methylene group, an acetylene group, or a compound having two or more known reactive groups in the molecule is used.
[0098]
As the crosslinking agent, a compound having two or more groups capable of forming a bond by a hydrogen bond, an ionic bond, a coordinate bond, or the like can be used.
As the crosslinking agent, known compounds can be used as coupling agents for resins, curing agents, polymerization agents, polymerization accelerators, coagulants, film-forming agents, film-forming aids, and the like. Examples of coupling agents include, for example, chlorosilanes, vinyl silanes, epoxy silanes, aminosilanes, alkoxyaluminum chelates, titanate coupling agents, etc. In addition, “Handbook: Rubber and plastic compounding chemicals” (rubber digest) The publicly known thing mentioned by the company edition) etc. can be used.
[0099]
-Charge control agent-
The image receiving layer of the present invention preferably contains a charge adjusting agent in order to adjust toner transfer, adhesion, and the like, and to prevent charge adhesion of the image receiving layer. Conventionally known various charge control agents can be used as the charge control agent. Examples of such a charge control agent include cationic surfactants, surfactants such as anionic surfactants, amphoteric surfactants, and nonionic surfactants, as well as polymer electrolytes and conductive metal oxides. Things can be used. For example, quaternary ammonium salts, polyamine derivatives, cation-modified polymethyl methacrylate, cationic antistatic agents such as cation-modified polystyrene, anionic antistatic agents such as alkyl phosphates and anionic polymers, fatty acid esters, polyethylene oxide, etc. Nonionic antistatic agents may be mentioned, but are not limited thereto.
[0100]
In the case where the toner has a negative charge, for example, a cation or a nonion is preferable as the charge adjusting agent blended in the image receiving layer.
Examples of the conductive metal oxide include ZnO and TiO.₂, SnO₂, Al₂O₃, In₂O₃, SiO₂, MgO, BaO, MoO₃Etc. These conductive metal oxides may be used alone or in combination with these composite oxides. In addition, the metal oxide may further contain a different element, for example, Al, In, etc. with respect to ZnO, such as TiO.₂Nb, Ta, etc., SnO₂Can contain (doping) Sb, Nb, a halogen element, or the like.
[0101]
-Other additives-
The material that can be used in the image-receiving layer of the present invention can contain various additives for improving the stability of the output image and improving the stability of the image-receiving layer itself. Additives for this purpose include various known antioxidants, anti-aging agents, degradation inhibitors, ozone degradation inhibitors, ultraviolet absorbers, metal complexes, light stabilizers, antiseptics, fungicides, etc. Can be mentioned.
[0102]
Examples of the antioxidant include a chroman compound, a coumaran compound, a phenol compound (eg, hindered phenol), a hydroquinone derivative, a hindered amine derivative, and a spiroindane compound. The antioxidant is described in JP-A No. 61-159644.
[0103]
Examples of the anti-aging agent include those described in "Handbook: Rubber / Plastic Compounding Chemicals Revised 2nd Edition" (1993, Rubber Digest Co.) p76-121.
[0104]
Examples of the ultraviolet absorber include benzotriazole compounds (described in U.S. Pat. No. 3,533,794), 4-thiazolidone compounds (described in U.S. Pat. No. 3,352,681), benzophenone compounds (described in JP-A-46-2784), and Examples thereof include ultraviolet absorbing polymers (described in JP-A-62-260152).
[0105]
Examples of the metal complex include U.S. Pat. Nos. 4,241,155, 4,425,018 and 4,254,195, JP-A-61-88256, JP-A-62-174741, JP-A-63-199248, JP-A-1-75568. Nos. 1 and 74272 are appropriate.
In addition, ultraviolet absorbers and light stabilizers described in “Handbook: Rubber / Plastic Compounding Chemicals Revised 2nd Edition” (1993, Rubber Digest Co.) p122-137 are also preferably used.
[0106]
As described above, known photographic additives can be added to the material that can be used in the image-receiving layer of the present invention. Examples of the photographic additive include Research Disclosure Magazine (hereinafter abbreviated as RD) No. 17643 (December 1978), No. 18716 (November 1979) and 307105 (November 1989), and the corresponding parts are summarized below.

[0107]
The image receiving layer of the present invention is provided by applying a coating solution containing a polymer used for the image receiving layer on the support with a wire coater or the like and drying. The coating liquid is prepared, for example, by dissolving an additive such as a thermoplastic polymer or a plasticizer in an organic solvent such as alcohol or ketone, or by uniformly dispersing the additive. Examples of the organic solvent used here include methanol, isopropyl alcohol, and methyl ethyl ketone. If the polymer used for the image receiving layer is water-soluble, the image receiving layer can be prepared by coating an aqueous polymer solution on the support. Moreover, about the polymer which is not water-soluble, it is also possible to apply | coat on a support body with an aqueous dispersion.
The film forming temperature of the polymer used in the present invention is preferably room temperature or higher for storage before printing, and preferably 100 ° C. or lower for fixing toner particles.
[0108]
The image receiving layer of the present invention has a coating mass after drying of, for example, 1 to 20 g / m.², Preferably 4-15 g / m²It is applied to become. The thickness of the image receiving layer is, for example, 1 to 20 μm, preferably 4 to 15 μm. Although there is no restriction | limiting in particular as thickness of the said image receiving layer, 1-30 micrometers is preferable and 2-20 micrometers is more preferable.
[0109]
[Physical properties of the image receiving layer]
The image receiving layer preferably has high whiteness. The whiteness is preferably 85% or more as measured by the method defined in JIS P 8123. Further, it is preferable that the spectral reflectance is 85% or more in the wavelength region of 440 nm to 640 nm and the difference between the maximum spectral reflectance and the minimum spectral reflectance in the same wavelength region is within 5%. Furthermore, it is more preferable that the spectral reflectance is 85% or more in the wavelength region of 400 nm to 700 nm, and the difference between the maximum spectral reflectance and the minimum spectral reflectance in the same wavelength region is within 5%.
Further, as the whiteness, specifically, CIE 1976 (L^*a^*b^*) In color space, L^*The value is preferably 80 or more, preferably 85 or more, and more preferably 90 or more. The white color is preferably as neutral as possible. The white color is L^*a^*b^*In space, (a^*)²+ (B^*)²Is preferably 50 or less, more preferably 18 or less, and even more preferably 5 or less.
[0110]
The image receiving layer preferably has high gloss. The glossiness is preferably 60 or more, more preferably 75 or more, and even more preferably 90 or more in the entire region from white without toner to black having the maximum density. .
However, the glossiness is preferably 110 or less. If it exceeds 110, it becomes like metallic luster, which is not preferable as image quality.
The glossiness can be measured based on JIS Z 8741.
[0111]
The image receiving layer preferably has high smoothness. As the smoothness, the arithmetic average roughness (Ra) is preferably 3 μm or less, more preferably 1 μm or less, and more preferably 0.5 μm or less in the entire region from white without toner to black having the maximum density. More preferably.
The arithmetic average roughness can be measured based on JIS B 0601, B 0651, B 0652.
[0112]
The image-receiving layer preferably has one of the following physical properties, more preferably a plurality of items, and most preferably all physical properties.
(1) The Tg (glass transition temperature) of the image receiving layer is 30 ° C. or higher and the toner Tg + 20 ° C. or lower.
(2) T1 / 2 (1/2 method softening point) of the image receiving layer is 60 to 200 ° C, preferably 80 to 170 ° C. Here, the 1/2 method softening point is a preheating time at an initial set temperature (for example, 50 ° C.), for example, 300 seconds, using a specific apparatus and applying a predetermined extrusion load under a specific condition. Later, evaluation is made at a temperature that is one-half of the difference between the piston stroke at the start and end of outflow at each temperature when the temperature is increased at a predetermined constant temperature increase rate.
(3) Tfb (outflow start temperature) of the image receiving layer is 40 to 200 ° C., preferably, Tfb of the image receiving layer is Tfb + 50 ° C. or less of the toner.
(4) The viscosity of the image receiving layer is 1 × 10⁵The temperature at which CP becomes 40 ° C. or higher is lower than that of toner.
(5) The storage elastic modulus (G ′) at the fixing temperature of the image receiving layer is 1 × 10²~ 1x10⁵Pa, loss modulus (G ″ is 1 × 10²~ 1x10⁵Pa.
(6) The loss tangent (G ″ / G ′), which is the ratio of the loss elastic modulus (G ″) at the fixing temperature of the image receiving layer and the storage elastic modulus (G ′), is 0.01 to 10.
(7) The storage elastic modulus (G ′) at the fixing temperature of the image receiving layer is −50 to +2500 with respect to the storage elastic modulus (G ″) at the fixing temperature of the toner.
(8) The inclination angle of the molten toner on the image receiving layer is 50 degrees or less, particularly 40 degrees or less.
The image receiving layer preferably satisfies the physical properties disclosed in Japanese Patent No. 2788358, JP-A-7-248637, JP-A-8-305067, JP-A-10-239889, and the like.
[0113]
The physical property (1) can be measured by a differential scanning calorimeter (DSC). The physical properties (2) to (3) can be measured using, for example, a flow tester CFT-500 or 500D manufactured by Shimadzu Corporation. The physical properties (5) to (7) can be measured using a rotational rheometer (for example, a dynamic analyzer RADII manufactured by Rheometric). The physical property (8) can be measured by a method disclosed in JP-A-8-334916 using a contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd.
[0114]
The image receiving layer is 1 × 10⁶~ 1x10¹⁵Ω / cm²It is preferable to have a surface electrical resistance in the range of (under conditions of 25 ° C. and 65% RH).
The surface resistance is 1 × 10⁶Ω / cm²If the ratio is less than 1, the amount of toner when the toner is transferred to the image receiving layer is not sufficient, and the density of the resulting toner image tends to be low, while the surface electrical resistance is 1 × 10.¹⁵Ω / cm²Exceeding the amount of charge will generate more charge than necessary during transfer, the toner will not be transferred sufficiently, the image density will be low, and electrostatic charge will easily adhere to the electrophotographic image receiving sheet, and during copying, Misfeed, double feed, discharge mark, toner transfer missing, etc. may occur.
[0115]
The surface electric resistance of the surface opposite to the image receiving layer with respect to the support is 5 × 10.⁸~ 3.2 × 10¹⁰Ω / cm²1 × 10 is preferred⁹~ 1x10¹⁰Ω / cm²Is more preferable.
In the present invention, the surface electrical resistance is measured in accordance with JIS K 6911, the sample is conditioned for 8 hours or more in an environment of a temperature of 20 ° C. and a humidity of 65%, and under the same environment, R8340 manufactured by Advantest Corporation. Is used, and measurement is performed after 1 minute has passed after energization under the condition of an applied voltage of 100V.
[0116]
[Other layers]
Examples of the other layers include a surface protective layer, a back layer, an adhesion improving layer, an intermediate layer, an undercoat layer, a cushion layer, a charge control (preventing) layer, a reflective layer, a color adjusting layer, a storage stability improving layer, and an adhesive. Examples include a prevention layer, an anti-curl layer, and a smoothing layer. These layers may be composed of a single layer or may be composed of two or more layers.
[0117]
-Surface protective layer-
The surface protective layer is for the purpose of protecting the surface of the electrophotographic image-receiving sheet of the present invention, improving storage stability, improving handleability, imparting writability, improving instrument passability, imparting anti-offset properties, etc. It can be provided on the surface of the image receiving layer. The surface protective layer may be a single layer or may be composed of two or more layers. In the surface protective layer, various thermoplastic resins, thermosetting resins, and the like can be used as a binder, and it is preferable to use the same type of resin as the image receiving layer. However, thermodynamic characteristics, electrostatic characteristics, and the like do not have to be the same as those of the image receiving layer, and can be optimized.
[0118]
The surface protective layer may contain the various additives described above that can be used for the image receiving layer. In particular, the surface protective layer may be blended with other additives such as a matting agent in addition to the release agent used in the present invention. In addition, as said mat agent, various well-known things are mentioned.
The outermost surface layer in the electrophotographic image-receiving sheet of the present invention (for example, the surface protective layer when a surface protective layer is formed) has good compatibility with the toner in terms of fixing properties. preferable. Specifically, the contact angle with the melted toner is preferably, for example, 0 to 40 degrees.
[0119]
-Back layer-
In the electrophotographic image-receiving sheet of the present invention, the back layer is on the opposite side of the image-receiving layer with respect to the support for the purpose of imparting backside output suitability, improving backside output image quality, improving curl balance, and improving device passability. Preferably it is provided.
Although there is no restriction | limiting in particular as a color of the said back layer, When the image receiving sheet for electrophotography of this invention is a double-sided output type image receiving sheet which forms an image also in a back surface, it is preferable that a back layer is also white. The whiteness and the spectral reflectance are preferably 85% or more like the surface.
Further, the back layer configuration may be the same as that on the image receiving layer side in order to improve the duplex output suitability. Various additives described above can be used for the back layer. As such an additive, it is particularly suitable to blend a matting agent, a charge adjusting agent and the like. The back layer may have a single layer configuration or a stacked configuration of two or more layers.
Further, in order to prevent offset at the time of fixing, when a releasable oil is used for the fixing roller or the like, the back layer may be oil absorbing.
[0120]
-Adhesion improvement layer, etc.-
The adhesion improving layer is preferably formed for the purpose of improving the adhesion between the support and the image receiving layer in the electrophotographic image receiving sheet of the present invention. The above-mentioned various additives can be blended in the adhesion improving layer, and it is particularly preferable to blend a crosslinking agent. The electrophotographic image receiving sheet of the present invention preferably further comprises a cushion layer or the like between the adhesion improving layer and the image receiving layer in order to improve toner acceptability.
[0121]
-Intermediate layer-
The intermediate layer can be formed, for example, between the support and the adhesion improving layer, between the adhesion improving layer and the cushion layer, between the cushion layer and the image receiving layer, and between the image receiving layer and the storage stability improving layer. . Of course, in the case of an electrophotographic image-receiving sheet comprising a support, an image-receiving layer, and an intermediate layer, the intermediate layer can be present, for example, between the support and the image-receiving layer.
[0122]
The thickness of the electrophotographic image-receiving sheet of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 50 to 350 μm is preferable, and 100 to 280 μm is more preferable.
[0123]
<Image formation>
The electrophotographic image-receiving sheet of the present invention can be suitably used for image formation with an electrophotographic toner by an electrophotographic method, and can be suitably used for color image formation with an electrophotographic color toner. In particular, it is preferably used in an image forming apparatus having at least an electrophotographic image receiving sheet conveying section, an electrostatic latent image forming section, a developing section, and a fixing belt.
[0124]
<< Color toner for electrophotography >>
The electrophotographic color toner used for the image formation contains at least a binder resin and a colorant, and if necessary, a release agent and other components.
[0125]
-Toner binder resin-
Examples of the binder resin include styrenes such as styrene and parachlorostyrene; vinyl esters such as vinyl naphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, methacryl Methylene aliphatic carboxylic acid esters such as ethyl acetate and butyl methacrylate; Vinyl nitriles such as acrylonitrile, methacrylonitrile, and acrylamide; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether Tells; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; single weight of vinyl monomers such as vinyl carboxylic acids such as methacrylic acid, acrylic acid and cinnamic acid Copolymers, copolymers thereof, and various polyesters can be used, and various waxes can be used in combination.
Among these resins, it is particularly preferable to use a resin of the same system as that used for the image receiving layer of the present invention.
[0126]
-Toner colorant-
As the colorant, those usually used in toners can be used without limitation. For example, carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, permanent orange GTR, pyrazolone. Orange, Vulcan Orange, Watch Young Red, Permanent Red, Brilliantamine 3B, Brilliantamine 6B, Daypon Oil Red, Pyrazolone Red, Risor Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Examples include various pigments such as oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, and malachite green oxalelate. Acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, thioindico, phthalocyanine, aniline black, polymethine, triphenyl Examples include various dyes such as methane, diphenylmethane, thiazine, thiazole, and xanthene. These colorants may be used alone or in combination of two or more.
The content of the colorant is preferably in the range of 2 to 8% by mass. If the content of the colorant is 2% by mass or more, the coloring power is not weakened. On the other hand, if it is 8% by mass or less, the transparency is not impaired, which is preferable.
[0127]
-Toner release agent-
As the mold release agent, all known waxes can be used in principle, but polar waxes containing nitrogen such as relatively low molecular weight high crystalline polyethylene wax, Fischer-Tropsch wax, amide wax, urethane compound, etc. Etc. are particularly effective. The polyethylene wax having a molecular weight of 1000 or less is particularly effective, and a range of 300 to 1000 is more preferable.
[0128]
The compound having a urethane bond is suitable because even if it has a low molecular weight, the solid state can be maintained and the melting point can be set high for the molecular weight due to the strength of cohesive force due to the polar group. The preferred range of molecular weight is 300-1000. The raw materials are a combination of diisocyanate compounds and monoalcohols, a combination of monoisocyanic acid and monoalcohol, a combination of dialcohols and monoisocyanic acid, a combination of trialcohols and monoisocyanic acid, triisocyanic acid Various combinations such as combinations of compounds and monoalcohols can be selected, but in order not to increase the molecular weight, it is preferable to combine a compound of a polyfunctional group and a monofunctional group, and an equivalent functional group amount. It is important to ensure that
[0129]
Specific examples of the monoisocyanate compound among the raw material compounds include dodecyl isocyanate, phenyl isocyanate and derivatives thereof, naphthyl isocyanate, hexyl isocyanate, benzyl isocyanate, butyl isocyanate, and allyl isocyanate. It is done.
Examples of the diisocyanate compound include tolylene diisocyanate, 4,4′diphenylmethane diisocyanate, toluene diisocyanate, 1,3-phenylene diisocyanate, hexamethylene diisocyanate, 4-methyl-m-phenylene diisocyanate, and isophorone diisocyanate. Can be mentioned.
As the monoalcohol, it is possible to use very common alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, and heptanol.
Among the raw material compounds, as the dialcohols, a number of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol; as the trialcohols, trimethylolpropane, triethylolpropane, trimethanolethane, etc. can be used. However, it is not necessarily limited to this range.
[0130]
These urethane compounds can be mixed with a resin and a colorant at the time of kneading and used as a kneaded and pulverized toner as in a normal release agent. In addition, when used in emulsion polymerization aggregation melting toner, it is dispersed in water together with an ionic surfactant, a polymer electrolyte such as a polymer acid or a polymer base, and heated to a melting point or higher to produce a homogenizer or pressure discharge type dispersion. A fine shearing agent is used to form fine particles, and a release agent particle dispersion of 1 μm or less can be prepared and used together with a resin particle dispersion, a colorant dispersion, and the like.
[0131]
-Toner and other components-
The toner may contain other components such as an internal additive, a charge control agent, and inorganic fine particles. As the internal additive, a magnetic material such as a metal such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese, an alloy, or a compound containing these metals can be used.
[0132]
As the charge control agent, various commonly used charge control agents such as quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments may be used. it can. A material that is difficult to dissolve in water is preferable from the viewpoint of controlling the ionic strength that affects the stability during aggregation and melting and reducing wastewater contamination.
[0133]
Examples of the inorganic fine particles include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, and the like. Usually, all external additives on the toner surface are used. It is preferable to use by dispersing with a molecular base.
[0134]
Furthermore, a surfactant can be used for emulsion polymerization, seed polymerization, pigment dispersion, resin particle dispersion, release agent dispersion, aggregation, and stabilization thereof. For example, anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap, cationic surfactants such as amine salt type and quaternary ammonium salt type, polyethylene glycol type, alkylphenol It is also effective to use a nonionic surfactant such as an ethylene oxide adduct system or a polyhydric alcohol system in combination. As a dispersing means at that time, a general means such as a rotary shear type homogenizer, a ball mill having a media, a sand mill, a dyno mill or the like can be used.
[0135]
An external additive may be further added to the toner as necessary. Examples of the external additive include inorganic powder and organic particles. Examples of the inorganic particles include SiO.₂TiO₂, Al₂O₃, CuO, ZnO, SnO₂, Fe₂O₃, MgO, BaO, CaO, K₂O, Na₂O, ZrO₂, CaO / SiO₂, K₂O. (TiO₂)_n, Al₂O₃・ 2SiO₂, CaCO₃, MgCO₃, BaSO₄, MgSO₄Etc. can be illustrated. Moreover, as said organic particle, resin powder, such as fatty acid or its derivative (s), powders, such as these metal salts, a fluorine resin, a polyethylene resin, an acrylic resin, can be used. The average particle diameter of these powders is, for example, 0.01-5 μm, preferably 0.1-2 μm.
[0136]
The method for producing the toner is not particularly limited, and (i) a step of forming aggregated particles in a dispersion obtained by dispersing resin particles to prepare an aggregated particle dispersion, (ii) in the aggregated particle dispersion. A step of adding and mixing a fine particle dispersion in which fine particles are dispersed to adhere the fine particles to the aggregated particles to form adhered particles; and (iii) heating and fusing the adhered particles to form toner particles. It is preferable that the toner is manufactured by a toner manufacturing method including the steps.
[0137]
-Toner physical properties-
The volume average particle diameter of the toner is preferably 0.5 μm or more and 10 μm or less.
If the volume average particle size of the toner is too small, there may be an adverse effect on toner handling (replenishability, cleaning properties, fluidity, etc.), and particle productivity may be reduced. On the other hand, if the volume average particle size of the toner is too large, the image quality and resolution due to graininess and transferability may be adversely affected.
The toner preferably satisfies the toner volume average particle size range and has a volume average particle size distribution index (GSDv) of 1.3 or less.
The ratio (GSDv / GSDn) of the volume average particle size distribution index (GSDv) to the number average particle size distribution index (GSDn) is preferably at least 0.95.
Further, the toner of the present invention preferably satisfies the volume average particle diameter range of the toner and has an average value of a shape factor represented by the following formula of 1.00 to 1.50.
Shape factor = [π × (2 × L)²] / (4 × S)
(However, L represents the maximum length of toner particles, and S represents the projected area of toner particles.)
When the toner satisfies the above conditions, it is effective for image quality, particularly graininess, and resolution, and it is difficult for transfer and omission to occur, and handling properties are not adversely affected even if the average particle size is not small. Become.
[0138]
The storage elastic modulus G ′ (measured at an angular frequency of 10 rad / sec) at 150 ° C. of the toner itself is suitably 10 to 200 Pa from the viewpoint of improving the image quality and preventing the offset property in the fixing process.
[0139]
(Image forming method)
In the image forming method of the present invention, at least an electrostatic latent image is formed and developed, and then transferred to the electrophotographic image receiving sheet of the present invention to form and fix the image.
[0140]
In the image forming method of the present invention, there is no particular limitation in addition to the above, and an image can be formed according to a normal electrophotographic method. For example, as the first aspect, the electrophotographic image-receiving sheet of the present invention is used. In addition, after forming a toner image, the image forming surface of the electrophotographic image receiving sheet is heated and pressurized with a fixing belt and a roller, cooled, and then peeled off from the fixing belt.
Further, as a second aspect, after a toner image is formed on the electrophotographic image receiving sheet of the present invention and fixed by a heat roller, the image forming surface of the electrophotographic image receiving sheet is further provided with a fixing belt and Examples of the method include heating and pressurizing with a roller, cooling, and then peeling from the fixing belt.
As a transfer method, a method used in a normal electrophotographic method, for example, a direct transfer method in which a toner image formed on a developing roller is directly transferred to an image receiving material, or after primary transfer to an intermediate transfer belt or the like. There is an intermediate transfer belt system for transferring to an image receiving material. From the viewpoint of environmental stability and high image quality, an intermediate transfer belt method is preferably used.
[0141]
In the image forming method, the toner transferred onto the electrophotographic image receiving sheet is fixed to the electrophotographic image receiving sheet using an electrophotographic apparatus having a fixing belt. As the belt fixing method, for example, an oilless type belt fixing method described in JP-A-11-352819, secondary transfer and fixing described in JP-A-11-231671 and JP-A-5-341666 are used. Methods to achieve at the same time are known. The electrophotographic apparatus having a fixing belt according to the present invention includes, for example, a belt-type toner fixing unit including at least an electrophotographic image receiving sheet conveying unit, an electrostatic latent image forming unit, a developing unit, and a fixing belt. The image forming apparatus further includes a heating and pressurizing unit that can melt and press the toner, and a cooling unit that can cool the heated image-receiving paper while being attached to the fixing belt. preferable. It is preferable that the fixing belt can convey the image receiving paper to which the toner is attached in a state of being in contact with the image receiving layer. By using an electrophotographic image receiving sheet having an image receiving layer in an electrophotographic apparatus having such a fixing belt, the toner attached to the image receiving layer is finely fixed without spreading on the image receiving paper, Since the molten toner is cooled and solidified in the close contact state, the toner is completely received in the image receiving layer and is received by the image receiving layer. Therefore, it is possible to obtain a glossy and smooth toner image with no image level difference.
[0142]
The electrophotographic image-receiving sheet of the present invention is particularly suitable for an image forming method using an oil-less belt fixing method, whereby the offset is greatly improved. However, it can be similarly used for various other image forming methods.
For example, by using the electrophotographic image receiving sheet of the present invention, a full color image can be suitably formed while improving the image quality and preventing cracks. The color image can be formed using an electrophotographic apparatus capable of forming a full color image. A typical electrophotographic apparatus has an image receiving paper transport section, a latent image forming section, and a developing section disposed in the vicinity of the latent image forming section. Depending on the model, a latent image is formed at the center of the apparatus main body. A toner image intermediate transfer portion adjacent to the image receiving portion and the image receiving paper transport portion.
[0143]
Further, as a method for improving the image quality, an adhesive transfer or heat-assisted transfer system is known instead of or in combination with electrostatic transfer or bias roller transfer. For example, Japanese Patent Laid-Open Nos. 63-113576 and 5-341666 describe specific structures thereof. In particular, a method using an intermediate transfer belt of a heat assisted transfer system is preferable. For example, an endless belt made of electroformed nickel is used as the intermediate belt. Further, it is preferable to provide a cooling device for the intermediate belt after toner transfer to the electrophotographic image receiving sheet or in the latter half of the transfer. The cooling device cools the toner (toner image) to the softening temperature of the binder resin used in it or the glass transition temperature of the toner + 10 ° C. or lower, efficiently transfers it to the electrophotographic image-receiving sheet, and peels it from the intermediate belt. Is possible.
[0144]
Fixing is an important process that affects the gloss and smoothness of the final image. As the fixing method, fixing by a heat and pressure roller, belt fixing using a belt, and the like are known, but the belt fixing method is preferable from the viewpoint of the image quality such as gloss and smoothness. Regarding the belt fixing method, for example, an oilless type belt fixing method described in JP-A-11-352819, secondary transfer and fixing described in JP-A-11-231671, and JP-A-5-341666 are performed. Methods to achieve at the same time are known. Further, primary pressing with a heat roller may be performed before pressing and heating with the fixing belt and the fixing roller.
[0145]
The surface of the fixing belt may be subjected to a surface treatment of silicone, fluorine, or a combination thereof in order to prevent toner releasability or toner component offset. Further, it is preferable to provide a belt cooling device in the latter half of the fixing so that the electrophotographic image-receiving sheet is peeled off satisfactorily. The cooling temperature is preferably not higher than the softening point of the toner binder resin and / or the polymer of the image receiving layer of the electrophotographic image receiving sheet, or not higher than the glass transition point + 10 ° C. On the other hand, at the initial stage of fixing, it is necessary to raise the temperature to a temperature at which the image receiving layer or toner of the electrophotographic image receiving sheet is sufficiently softened. Specifically, the cooling temperature is preferably 70 ° C. or lower and 30 ° C. or higher for practical use, and is preferably 180 ° C. or lower and 100 ° C. or higher in the initial fixing stage.
[0146]
Hereinafter, a specific description will be given based on FIG. 1 showing an example of an image forming apparatus having a typical fixing belt. The embodiment of the present invention is not limited to the embodiment shown in FIG.
First, the toner (12) is transferred to the electrophotographic image receiving sheet (1) by an image forming apparatus (not shown). The image receiving paper (1) to which the toner (12) is attached is conveyed to point A by a conveying facility (not shown), passes between the heating roller (14) and the pressure roller (15), and is received by an electrophotographic image receiving device. The image receiving layer or toner (12) of the sheet (1) is heated and pressed at a temperature (fixing temperature) and pressure at which it is sufficiently softened.
[0147]
Here, the fixing temperature means the temperature of the surface of the image receiving layer measured at the positions of the heating roller (14), the pressure roller (15) and the nip portion at the point A. The fixing temperature varies depending on the material of the image-receiving layer in the electrophotographic image-receiving sheet. Specifically, it is preferably 90 to 120 ° C, more preferably 100 to 110 ° C, and still more preferably 103 to 107 ° C. . The pressure means the pressure on the surface of the image receiving layer measured at the heating roller (14), the pressure roller (15) and the nip, and specifically, 1 to 10 kg / cm.²2-7 kg / cm²Is more preferable. While being heated and pressurized in this manner, the release sheet that was discretely present in the image receiving layer while the electrophotographic image receiving sheet (1) was later conveyed to the cooling device (16) by the fixing belt (13). The agent (not shown) is sufficiently heated to melt and move to the surface of the image receiving layer. The released release agent forms a release agent layer (film) on the surface of the image receiving layer. Thereafter, the electrophotographic image-receiving sheet (1) is conveyed to the cooling device (16) by the fixing belt (13), for example, below the softening point of the binder resin used for the polymer and / or toner of the image-receiving layer or glass It is cooled to a temperature not higher than the transition point + 10 ° C, preferably 20 to 80 ° C, more preferably room temperature (25 ° C). As a result, the release agent layer (film) formed on the surface of the image receiving layer is cooled and solidified to form a release agent layer formed by the change of the release agent in the image receiving layer.
The cooled electrophotographic image-receiving sheet (1) is further conveyed to point B by the fixing belt (13), and the fixing belt (13) moves on the tension roller (17). Accordingly, the electrophotographic image receiving sheet (1) and the fixing belt (13) are peeled off at the point B. In addition, it is preferable to set the diameter of the tension roll to be small so that the electrophotographic image-receiving sheet is peeled off from the belt by its own rigidity (waist strength).
[0148]
Here, it is appropriate that the fixing belt used in the image forming apparatus is an endless belt formed using, for example, polyimide, electroformed nickel, aluminum, or the like as a base material.
It is preferable that a thin film made of at least one selected from the group consisting of silicone rubber, fluororubber, silicone resin, and fluororesin is formed on the surface of the fixing belt. Among these, a mode in which a fluorocarbon siloxane rubber layer having a uniform thickness is provided on the surface of the fixing belt, a silicone rubber layer having a uniform thickness on the surface of the fixing belt, and the silicone rubber layer An embodiment in which a fluorocarbonsiloxane rubber layer is provided on the surface is preferred.
[0149]
The fluorocarbon siloxane rubber preferably has a perfluoroalkyl ether group and / or a perfluoroalkyl group in the main chain.
Such a fluorocarbon siloxane rubber includes (A) a fluorocarbon siloxane having the following general formula (1) as a main component and an aliphatic unsaturated group, and (B) two or more ≡SiH groups in one molecule. Organopolysiloxane and / or fluorocarbon siloxane, wherein the content of the ≡SiH group is 1 to 4 times the molar amount of the aliphatic unsaturated group in the fluorocarbon siloxane rubber composition, (C) filling A cured product of a fluorocarbon siloxane rubber composition containing an agent and (D) an effective amount of a catalyst is preferably used.
[0150]
The (A) component fluorocarbon polymer is mainly composed of a fluorocarbon siloxane having a repeating unit represented by the following general formula (1) and has an aliphatic unsaturated group.
[0151]
[Chemical 1]

[0152]
Here, in the above formula (1), R¹⁰Is an unsubstituted or substituted monovalent hydrocarbon group having preferably 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 3 carbon atoms, particularly a methyl group. Is preferred. a and e are each 0 or 1, b and d are each an integer of 1 to 4, and c is an integer of 0 to 8. Moreover, x is an integer greater than or equal to 1, Preferably it is 10-30.
[0153]
Examples of the component (A) include those represented by the following formula (2).
[0154]
[Chemical 2]

[0155]
In the component (B), examples of the organopolysiloxane having ≡SiH groups include organohydrogenpolysiloxanes having at least two hydrogen atoms bonded to silicon atoms in the molecule.
[0156]
In the fluorocarbon siloxane rubber composition used in the present invention, when the fluorocarbon polymer as the component (A) has an aliphatic unsaturated group, the above-described organohydrogenpolysiloxane can be used as a curing agent. . That is, in this case, a cured product is formed by an addition reaction that occurs between an aliphatic unsaturated group in the fluorocarbon siloxane and a hydrogen atom bonded to a silicon atom in the organohydrogenpolysiloxane.
[0157]
As such organohydrogenpolysiloxane, various organohydrogenpolysiloxanes used in addition-curable silicone rubber compositions can be used.
[0158]
The above-mentioned organohydrogenpolysiloxane generally has at least one ≡SiH group, particularly 1 to 5 with respect to one aliphatic unsaturated hydrocarbon group in the fluorocarbon siloxane of component (A). It is suitable to mix | blend in such a ratio.
[0159]
Further, the fluorocarbon having an ≡SiH group may be a unit of the above formula (1) or R in the formula (1).¹⁰Is preferably a dialkylhydrogensiloxy group and the terminal is a ≡SiH group such as a dialkylhydrogensiloxy group or a silyl group, and examples thereof include those represented by the following formula (3).
[0160]
[Chemical 3]

[0161]
As the filler of component (C), various fillers used in general silicone rubber compositions can be used. For example, fumed silica, precipitated silica, carbon powder, titanium dioxide, aluminum oxide, quartz powder, reinforcing fillers such as talc, sericite and bentonite, fibrous fillers such as asbestos, glass fiber, organic fiber, etc. It can be illustrated.
[0162]
As the catalyst of component (D), chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid and olefin, platinum black or palladium, which are known as addition reaction catalysts, platinum, alumina, silica, carbon, etc. Examples include those supported on a carrier, complex of rhodium and olefin, group VIII element of periodic table such as chlorotris (triphenylphosphine) rhodium (Wilkinson catalyst), rhodium (III) acetylacetonate, etc. However, these complexes are preferably used by dissolving in a solvent such as alcohol, ether, or hydrocarbon.
[0163]
In the fluorocarbon siloxane rubber composition used in the present invention, various compounding agents can be added as long as the object of the present invention to improve solvent resistance is not impaired. For example, diphenylsilane diol, low-polymerization degree molecular chain terminal hydroxyl-blocked dimethylpolysiloxane, dispersant such as hexamethyldisilazane, heat resistance improver such as ferrous oxide, ferric oxide, cerium oxide, iron octylate Further, colorants such as pigments can be blended as necessary.
[0164]
The fixing belt is obtained by coating the surface of a heat-resistant resin or metal belt main body with the fluorocarbon siloxane rubber composition, followed by heat-curing. If necessary, m-xylene hexafluoride is further obtained. It can be diluted with a solvent such as benzotrifluoride to form a coating solution, which can be applied by a general coating method such as spray coating, dip coating, or knife coating. The temperature and time for heat curing can be selected as appropriate, and are selected according to the type of belt body and the manufacturing method, etc., in the range of normal temperature of 100 to 500 ° C. and time of 5 seconds to 5 hours.
[0165]
The thickness of the fluorocarbon siloxane rubber layer formed on the surface of the fixing belt is not particularly limited. However, in order to obtain good image fixing properties by preventing toner releasability or toner component offset. 500 μm, particularly 40 to 200 μm is preferable.
[0166]
The method for forming an image on the electrophotographic image-receiving sheet of the present invention is not particularly limited to the method shown in FIG. 1 as long as it is the image forming method of the present invention using a fixing belt.
For example, in the image forming method of the present invention, a color image can be preferably formed. The color image can be formed using an electrophotographic apparatus capable of forming a full color image. A typical electrophotographic apparatus has an image receiving sheet conveying section, a latent image forming section, and a developing section arranged close to the latent image forming section. Depending on the model, a latent image is formed at the center of the apparatus main body. A toner image intermediate transfer portion in proximity to the image receiving portion and the image receiving sheet conveying portion.
[0167]
Furthermore, as a method for improving the image quality, an adhesive transfer or heat-assisted transfer system is known instead of or in combination with electrostatic transfer or bias roller transfer. For example, Japanese Patent Laid-Open Nos. 63-113576 and 5-341666 describe specific structures thereof. In particular, a method using a heat-assisted transfer type intermediate transfer belt is preferable when a toner having a small particle diameter is used.
[0168]
According to the image forming method of the present invention, even when an oilless machine having no fixing oil is used, it is possible to prevent the image receiving sheet and the toner from being peeled off or the image receiving sheet and the toner component from being offset, thereby realizing stable paper feeding. At the same time, it is possible to realize a good image having unprecedented good glossiness and rich in photographic feeling.
[0169]
In the image forming method of the present invention, the resin contained in the layer closest to the support in the image-receiving layer of the electrophotographic image-receiving sheet at the time of fixing, particularly in that an image having a good glossiness can be formed. The melt viscosity is preferably equal to or higher than the melt viscosity of the resin contained in the other layer. Specifically, at the time of fixing, it is preferably at least 3 times the melt viscosity of the resin contained in the layer farthest from the support among the laminated layers in the image receiving layer, more preferably at least 10 times. preferable. In addition, when the image receiving layer in the electrophotographic image receiving sheet has a multilayer structure of three or more layers, during fixing, the resin contained in the layer closest to the support and the layer farthest from the support in the image receiving layer is melted. The viscosity is preferably equal to or higher than the melt viscosity of the resin contained in a layer other than the layer closest to the support and the layer farthest from the support.
The melt viscosity can be obtained by measuring the viscosity or shear modulus when the resin is in a molten state using a known melt viscosity measuring device.
[0170]
The electrophotographic image-receiving sheet is particularly suitable for an image forming method using an oilless belt fixing method, whereby the offset is greatly improved. However, it can be similarly used in various other image forming methods.
For example, by using the electrophotographic image receiving sheet, a full color image can be suitably formed while improving the image quality and preventing cracks. The color image can be formed using an electrophotographic apparatus capable of forming a full color image. A typical electrophotographic apparatus has an image receiving paper transport section, a latent image forming section, and a developing section disposed in the vicinity of the latent image forming section. Depending on the model, a latent image is formed at the center of the apparatus main body. A toner image intermediate transfer portion adjacent to the image receiving portion and the image receiving paper transport portion.
[0171]
Further, as a method for improving the image quality, an adhesive transfer or heat-assisted transfer system is known instead of or in combination with electrostatic transfer or bias roller transfer. For example, Japanese Patent Laid-Open Nos. 63-113576 and 5-341666 describe specific structures thereof. In particular, a method using an intermediate transfer belt of a heat assisted transfer system is preferable. For example, an endless belt made of electroformed nickel is used as the intermediate belt. Further, it is preferable to provide a cooling device for the intermediate belt after toner transfer to the electrophotographic image receiving sheet or in the latter half of the transfer. With this cooling device, the toner (toner image) is cooled below the softening temperature of the binder resin used in it or the glass transition temperature of the toner, and is efficiently transferred to the electrophotographic image-receiving sheet and can be peeled off from the intermediate belt. It becomes.
[0172]
Fixing is an important process that affects the gloss and smoothness of the final image. As the fixing method, fixing by a heat and pressure roller, belt fixing using a belt, and the like are known, but the belt fixing method is preferable from the viewpoint of the image quality such as gloss and smoothness. Regarding the belt fixing method, for example, an oilless type belt fixing method described in JP-A-11-352819, secondary transfer and fixing described in JP-A-11-231671, and JP-A-5-341666 are performed. Methods to achieve at the same time are known. Further, primary pressing with a heat roller may be performed before pressing and heating with the fixing belt and the fixing roller.
[0173]
Further, at the time of fixing, as the set temperature of the surface of the belt, it is preferable that the image receiving layer in the electrophotographic image receiving sheet can be set within the above-mentioned numerical range of the fixing temperature. ), It is preferably about 130 to 160 ° C, more preferably about 140 to 150 ° C. Further, the conveyance speed (mm / sec) of the fixing machine is not particularly limited and is appropriately selected depending on the purpose, but is preferably about 5 to 200 mm / sec, and more preferably about 20 to 60 mm / sec.
[0174]
As described above, an image using the electrophotographic toner and a color image using the electrophotographic color toner are formed on the electrophotographic image receiving sheet of the present invention. The image-receiving sheet for electrophotography of the present invention has the same image, texture (glossiness, uniformity, thickness, waist, touch, etc.) as silver halide photographic prints, handling properties (light resistance, dark storage stability, water resistance, Adhesion resistance, scratch resistance, curl resistance, tearability at the time of disposal, etc.), and more excellent properties than silver halide photographic prints, such as double-sided output and backside writing, especially glossiness In addition, an extremely good image is formed, and surface deterioration due to humidity change is suppressed, so that a high-quality image can be formed. Therefore, the electrophotographic image-receiving sheet of the present invention can be suitably used in various fields, but can be particularly suitably used as photo paper.
[0175]
【Example】
Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “%” and “part” represent “% by mass” and “part by mass”, respectively.
[0176]
Example 1
-Preparation of support-
Hardwood bleached kraft pulp (LBKP) was beaten with a disc refiner to 300 cc (Canadian standard freeness, CFS) and adjusted to a fiber length of 0.58 mm. Additives were added to the pulp stock at the following ratio based on the mass of the pulp.
・ Cation starch …… 1.2%
・ Alkyl ketene dimer (AKD) ・ ・ ・ ・ ・ ・ 0.5%
・ Anionic polyacrylamide: 0.3%
・ Epoxidized aliphatic amide (EFA) 0.2%
・ Polyamide polyamine epichlorohydrin ・ 0.3%
The alkyl part in the alkyl ketene dimer (AKD) is derived from a fatty acid mainly composed of behenic acid, and the fatty acid part in the epoxidized aliphatic amide (EFA) is derived from a fatty acid mainly composed of behenic acid. doing.
[0177]
The pulp paper stock obtained as described above was measured at a basis weight of 150 g / m using a long paper machine.²Was made. Polyvinyl alcohol (PVA) 1.0 g / m by a size press machine in the middle of the drying zone of the long paper machine.², CaCl₂0.8g / m²Attached. And at the end of the paper making process, the density is 1.01 g / cm using a soft calendar.³Adjusted. The base paper obtained above was passed through such that the side on which the image receiving layer was formed was in contact with a metal roll (surface temperature: 140 ° C.). Thus, a support was obtained. The Oken type smoothness of the support was 265 seconds, and the stequito size was 127 seconds.
[0178]
-Preparation of coating solution for image receiving layer (upper layer)-
The components of the following image-receiving layer (upper layer) coating solution were mixed and stirred to prepare an image-receiving layer coating solution.
[0179]
--- Components of image-receiving layer (upper layer) coating solution-
Carnauba wax (manufactured by Chukyo Yushi Co., Ltd .; Cerozol 524) ... 15.0 g
-Polyester resin aqueous dispersion (manufactured by Unitika; solid content 30%, Tg = 48 ° C., KZA-7049) 100.0 g
・ Thickener (manufactured by Meisei Chemical Co., Ltd .; Alcox E30) ... 3.0 g
・ Anionic surfactant (AOT): 0.5g
・ Ion exchange water: 80ml
The viscosity of the prepared coating solution for the image receiving layer (upper layer) was 78 mPa · s, and the surface tension was 32 mN / m.
[0180]
-Preparation of coating solution for image-receiving layer (lower layer; layer closest to support)-
The components of the following image-receiving layer (lower layer) coating solution were mixed and stirred to prepare an image-receiving layer (lower layer) coating solution.
[0181]
--- Components of image-receiving layer (lower layer) coating solution--
・ Styrene acrylic varnish ・ ・ ・ ・ ・ ・ 100.0g
(Solid content 26.8%, Tg = 62 ° C., BH-997L, manufactured by Seiko Chemical Co., Ltd.)
・ Anionic surfactant (AOT) ... 1.5g
・ Ion-exchanged water ... 20ml
[0182]
The viscosity of the obtained image-receiving layer (lower layer) coating solution was 28 mPa · s, and the surface tension was 34 mN / m.
[0183]
-Preparation of coating solution for back layer-
The components of the following back layer coating solution were mixed and stirred to prepare a back layer coating solution.
[0184]
--- Back layer coating liquid-
・ Acrylic resin water dispersion: 150.0 g
(Dainippon Ink, Dick Fine K-96, solid content 30%)
・ Matting agent (manufactured by Sekisui Plastics Co., Ltd .; Techpolymer MBX-8) ... 8.0 g
・ Release agent (manufactured by Chukyo Yushi Co., Ltd .; Hydron D337) ... 5.0g
・ Anionic surfactant (AOT): 0.5g
・ Ion exchange water: 40 ml
[0185]
The viscosity of the prepared coating solution for the back layer was 60 mPa · s, and the surface tension was 34 mN / m.
[0186]
-Formation of image receiving layer-
The prepared back layer coating solution was applied to the back surface of the support using a bar coater. Next, the image receiving layer (lower layer) coating solution and the image receiving layer (upper layer) coating solution thus prepared were sequentially coated on the surface of the support using a bar coater to form an image receiving layer. The coating amount is 9.5 g / m in dry mass for the back layer.²It was 5.0 g for the image receiving layer (lower layer; layer closest to the support) and 10.0 g in terms of dry mass for the image receiving layer (upper layer).
The back layer and the image receiving layer were dried with hot air online after coating. For drying, the amount of drying air and the temperature were adjusted so that both the back surface and the toner image-receiving surface were dried within 2 minutes after coating. The drying point was the point at which the coating surface temperature was the same as the wet bulb temperature of the drying air.
After drying, a calendar process was performed. The calendar process was performed at a pressure of 147 N / cm (15 Kgf / cm) using a gloss calendar with the temperature of the metal roller adjusted to 50 ° C.
Thus, an electrophotographic image-receiving sheet was produced.
[0187]
-Image formation-
A color image was formed on the produced electrophotographic image-receiving sheet as follows.
An electrophotographic printer (manufactured by Fuji Xerox Co., Ltd .; DocuCenter Color 400CP) was used as the color image forming apparatus. In this electrophotographic printer, the fixing unit was used in place of the fixing device as shown in FIG. Using this electrophotographic printer, a gray rectangular image and a blue rectangular image were formed in which the density was changed stepwise from a white background to the maximum density (black) under the conditions of 23 ° C. and 55% RH. Then, after these image formations, fixing was performed with the image forming surface facing upward by a belt-fixing type color image forming apparatus including the fixing device shown in FIG.
[0188]
The color image forming apparatus includes an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit. The electrostatic latent image forming unit includes a charger and an exposure unit, the developing unit includes a developing unit for each toner of cyan toner, yellow toner, magenta toner, and black toner, and the transfer unit is an intermediate transfer unit. The fixing unit has a fixing device shown in FIG.
[0189]
In the color image forming apparatus, an electrostatic latent image of a rectangular image is formed by the electrostatic latent image forming unit. The developing unit develops the electrostatic latent image of the rectangular image using cyan, yellow, magenta, and black electrophotographic toners, and the gray rectangular image and the blue color of which the density is changed stepwise. A rectangular image was formed. The transfer means transfers the gray rectangular image and the blue rectangular image whose density has been changed stepwise to the electrophotographic image receiving sheet. The fixing unit fixed the gray rectangular image and the blue rectangular image, which were transferred to the electrophotographic image receiving sheet and the density was changed stepwise. As a result, a gray rectangular image and a blue rectangular image in which the density was changed stepwise were formed on the electrophotographic image receiving sheet.
[0190]
In this embodiment, the conveyance speed of the fixing belt 13 is 52 mm / second, and the nip pressure of the nip portion (between the fixing belt 13 and the pressure roller 15 pressed by the heating roller 14 and the pressure roller 15). The nip pressure is 0.15 MPa (2 kgf / cm²The set temperature of the heating roller 14, that is, the fixing temperature is 105 ° C., and the set temperature of the pressure roller 15 is 145 ° C. When the electrophotographic image receiving paper 1 is peeled off after being cooled by the cooling device 16. The temperature of the fixing belt 13 is 50 ° C. or less.
As a fixing belt base material, DY39-115, a primer for silicone rubber, is applied to a base layer made of polyimide by Toray Dow Corning Silicone Co., then air-dried for 30 minutes, and then DY35-796AB, a silicone rubber precursor, 100. A coating film was formed by dip coating a coating solution prepared with 30 parts by mass of n parts and n-hexane, and primary vulcanization was performed at 120 ° C. for 10 minutes to obtain 40 μm of silicone rubber.
On this silicone rubber layer, 100 parts by mass of SIFEL610, a fluorocarbon siloxane rubber precursor manufactured by Shin-Etsu Chemical Co., Ltd., and a fluorine-based solvent (a mixed solvent of m-xylene hexafluoride, perfluoroalkane, and perfluoro (2-butyltetrahydrofuran)) After forming a coating film by dip coating the coating solution adjusted by 20 parts by mass, primary vulcanization at 120 ° C. for 10 minutes and secondary vulcanization at 180 ° C. for 4 hours are performed, and the fluorocarbon siloxane rubber has a film thickness of 20 μm. A fixing belt having
[0191]
<Glossiness measurement>
About the image formed in the image receiving sheet for electrophotography, each gray density part was measured with the glossiness measuring apparatus (Micro Trigloss, Toyo Seiki Seisakusho make). Table 1 and FIG. 2 show the minimum gloss values when measured at an angle of 20 degrees. Moreover, the relief angle was measured as follows. The results are shown in Table 1. FIG. 3 shows the relationship between the relief angle and the glass transition temperature (° C.) of the resin used for the image-receiving layer (lower layer) coating solution.
[0192]
-Relief angle measurement method-
The surface area of the boundary area between the black part and the white part on the image was measured with a nano metro 110F manufactured by Kuroda Seiko Co., Ltd. at a pitch of 0.01 and a cutoff of 0.05, and an angle was determined from the shape.
[0193]
<Observation of surface change due to humidity change>
The electrophotographic image-receiving sheet was observed for surface changes due to changes in humidity as follows, and evaluated according to the following evaluation criteria. The results are shown in Table 1.
An image including a black portion and a white portion was output in a 23 ° C.-80% RH environment and allowed to stand overnight in the same environment. Put the print in a sealed container in the same environmental atmosphere, transfer it to each container in a 23 ° C-30% RH environment, open it in the same environment, observe the change in surface condition visually, and observe the following evaluation criteria. evaluated.
[0194]
-Evaluation criteria-
○: Non-gloss due to humidity change (increase in irregularities on the surface of the surface) is observed only slightly, and there is almost no change in surface shape.
Δ: Non-glossiness (increase in unevenness on the surface of the surface) accompanying the change in humidity is slightly observed, and there is a slight change in surface condition.
-X: Non-glossiness (increase in unevenness on the surface of the surface) and cracks due to humidity change are observed, and the surface change is remarkable.
[0195]
(Examples 2-6 and Comparative Examples 1-3)
In Example 1, an electrophotographic image-receiving sheet was prepared in the same manner as in Example 1, except that the styrene acrylic varnish in “Coating solution for image-receiving layer (lower layer)” was replaced with the components shown in Table 1. Evaluation was performed in the same manner. The results are shown in Table 1 and FIGS.
[0196]
[Table 1]

[0197]
However, in Table 1, “* 1” is SBR latex (Nippol series, manufactured by Nippon Zeon), “* 2” is NBR latex (soap-free type, manufactured by Nippon Zeon), “* 3 ”is core-shell styrene acrylic latex (soap-free type, Tg (core / shell) = 70/107 ° C. (overall Tg = 15 ° C.), mass ratio (core / shell) = 1/1),“ * 4 ”is , Polyester latex (number average molecular weight = 6,500, Mw / Mn = 2.4), “* 5” is styrene acrylic latex (Aquabrid series, manufactured by Daicel Chemical Industries), “* 6” is core-shell latex ( Core / shell = polystyrene / modified SBR, Tg (core / shell) = 100/0 ° C. (overall Tg = about 100 ° C.)).
[0198]
In the examples, the glass transition temperature (Tg) of the resin contained in the image receiving layer (lower layer) is equal to or higher than the glass transition temperature of the resin contained in the image receiving layer (upper layer), and the hardness of the image receiving layer (lower layer) is the image receiving layer. It was found that the hardness was not less than the hardness of the (upper layer), the glossiness in the image was excellent, and the surface change due to humidity change was suppressed.
[0199]
(Example 7)
In “Formation of image-receiving layer” in Example 1, the prepared coating solution for the image-receiving layer (lower layer) and the coating solution for the image-receiving layer (upper layer) were coated on the support surface at the same time as in Example 1 When an image receiving layer was formed, an image was formed, and each measurement was performed, excellent results were obtained as in Example 1.
[0200]
【The invention's effect】
According to the present invention, various problems in the prior art are solved, and the image, texture (for example, glossiness, uniformity, thickness, waist, touch feeling, etc.) and handling properties (for example, light resistance, darkness, etc.) are the same as silver halide photographic prints. Storage properties, water resistance, adhesion resistance, scratch resistance, curl resistance, easy tear when discarded, etc., and more excellent properties than silver halide photographic prints (for example, double-sided output, backside writing) Etc.), an image having an extremely good glossiness can be formed, and an image receiving sheet for electrophotography can be provided in which deterioration of the surface condition due to changes in humidity is suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of a fixing belt type electrophotographic apparatus.
FIG. 2 is a graph showing the relationship between the glass transition temperature (Tg) of the resin contained in the coating solution for the image receiving layer (lower layer) (the layer closest to the support) and the minimum glossiness.
FIG. 3 is a graph showing the relationship between the relief angle and the glass transition temperature (° C.) of the resin used in the image-receiving layer (lower layer) coating solution.
[Explanation of symbols]
1 Image receiving sheet for electrophotography
12 Toner
13 Fixing belt
14 Heating roller
15 Pressure roller
16 Cooling device
17 Tension roller

Claims (20)

For electrophotography, comprising an image receiving layer having a laminate structure of two or more layers on a support, wherein the hardness of the layer closest to the support in the image receiving layer is equal to or higher than the hardness of other layers Image receiving sheet. 2. The image receiving image for electrophotography according to claim 1, wherein in the image receiving layer, the melt viscosity at the fixing temperature of the resin contained in the layer closest to the support is equal to or higher than the melt viscosity at the fixing temperature of the resin contained in the other layer. Sheet. The electrophotographic image-receiving sheet according to claim 2, wherein the fixing temperature is any one of 90 to 120 ° C. The glass transition temperature (Tg) of the resin contained in the layer closest to the support in the image receiving layer is equal to or higher than the glass transition temperature (Tg) of the resin contained in the other layer. Electrophotographic image-receiving sheet. 5. The flow start temperature (Ts) of the resin contained in the layer closest to the support in the image receiving layer is equal to or higher than the flow start temperature (Ts) of the resin contained in the other layer. Electrophotographic image-receiving sheet. It has an image receiving layer composed of at least two layers on the support, and the glass transition temperature (Tg) of the resin contained in the layer closest to the support in the image receiving layer is 80 ° C. or higher. A characteristic electrophotographic image-receiving sheet. 7. The electrophotographic image according to claim 1, wherein in the image receiving layer, the layer closest to the support contains a resin having a glass transition temperature (Tg) of 80 ° C. or higher and a resin having a glass transition temperature (Tg) of 25 ° C. or lower. Image receiving sheet. An image-receiving layer having a laminate structure of at least two layers on the support, and the layer closest to the support in the image-receiving layer has a glass transition temperature (Tg) in the core portion of 80 ° C. or more and in the shell portion An electrophotographic image-receiving sheet comprising a core / shell resin having a glass transition temperature (Tg) of 25 ° C. or lower and a core / shell content ratio (mass ratio) of 1 or more. The image receiving layer has a multilayer structure of three or more layers, and the hardness of the image receiving layer in the layer closest to the support and the layer farthest from the support is other than the layer closest to the support and the layer farthest from the support The electrophotographic image-receiving sheet according to any one of claims 1 to 8, which has a hardness equal to or higher than the hardness of the layer. The image receiving layer has a multilayer structure of three or more layers, and in the image receiving layer, the layer having the closest melt viscosity at the fixing temperature of the resin contained in the layer closest to the support and the layer farthest from the support. The electrophotographic image-receiving sheet according to any one of claims 1 to 9, wherein the resin contained in a layer other than the layer farthest from the support is equal to or higher than the melt viscosity at the fixing temperature. The electrophotographic resin according to any one of claims 1 to 10, wherein the thermoplastic resin contained in at least the image receiving layer on the outermost surface is a self-dispersing water-based polyester resin emulsion satisfying the following characteristics (1) to (4): Image receiving sheet.
(1) Number average molecular weight (Mn) = 5000 to 10,000
(2) Molecular weight distribution (mass average molecular weight / number average molecular weight) ≦ 4
(3) Glass transition temperature (Tg) = 40-100 ° C.
(4) Volume average particle diameter = 20 to 200 nmφ The electrophotographic image-receiving sheet according to any one of claims 1 to 11, wherein at least one image-receiving layer contains a wax having a melting point of 70C to 95C. The electrophotographic image-receiving sheet according to any one of claims 1 to 10, wherein the support is selected from a base paper, a synthetic paper, a synthetic resin sheet, a coated paper, and a laminated paper. 12. The electrophotographic image receiving sheet according to claim 1, wherein the electrophotographic image receiving sheet is used in an image forming apparatus having at least an electrophotographic image receiving sheet conveying section, an electrostatic latent image forming section, a developing section, and a fixing belt. . The electrophotographic image-receiving sheet according to claim 14, wherein a fluorocarbonsiloxane rubber layer having a uniform thickness is provided on the surface of the fixing belt. The electrophotographic image-receiving sheet according to claim 14, wherein the surface of the fixing belt has a silicone rubber layer having a uniform thickness, and the silicone rubber layer is provided with a fluorocarbonsiloxane rubber layer. The electrophotographic image-receiving sheet according to claim 15 or 16, wherein the fluorocarbon siloxane rubber has a perfluoroalkyl ether group and / or a perfluoroalkyl group in a main chain. At least forming an electrostatic latent image, developing the electrostatic latent image, and then transferring the image to an electrophotographic image receiving sheet according to any one of claims 1 to 17 to form and fix the image. Image forming method. The image forming method according to claim 18, wherein, in fixing, the melt viscosity of the resin contained in the layer closest to the support in the image receiving layer is equal to or higher than the melt viscosity of the resin contained in the other layer. The image receiving layer has a multilayer structure of three or more layers, and the layer having the melt viscosity of the resin contained in the layer closest to the support and the layer farthest from the support in the image receiving layer is the closest to the support during fixing. The image forming method according to claim 18 or 19, which is not less than the melt viscosity of a resin contained in a layer other than the layer farthest from the support.

Images