JP3905029B2 - Aqueous dispersion of core / shell type latex particles for use in electrophotographic toner image-receiving layer, electrophotographic image-receiving sheet using the aqueous dispersion, method for producing the same, and image forming method - Google Patents

Description

【０１１４】
本発明のトナー受像層は、前記支持体上に、電子写真用トナー受像層に使用されるコア／シェル型ラテックス粒子の水分散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。
【０１１５】
本発明のトナー受像層は、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。
前記トナー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。
【０１１６】
〔トナー受像層の諸物性〕
前記トナー受像層は、白色度が高いのが好ましい。該白色度としては、ＪＩＳＰ 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。
【０１１７】
前記トナー受像層としては、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。
【０１１８】
前記トナー受像層は、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。
【０１１９】
前記トナー受像層は、以下の項目の内における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）トナー受像層のＴｇ（ガラス転移温度）が３０℃以上、トナーのＴｇ＋２０℃以下である。
（２）トナー受像層の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）トナー受像層のＴｆｂ（流出開始温度）が、４０〜２００℃、好ましくは、トナー受像層のＴｆｂが、トナーのＴｆｂ＋５０℃以下である。
（４）トナー受像層の粘度が１×１０^５ＣＰになる温度が、４０℃以上、トナーのそれより低い。
（５）トナー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、１×１０²〜１×１０^５Ｐａである。
（６）トナー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）トナー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）溶融トナーのトナー受像層上の傾斜角が、５０度以下、特に４０度以下である。
また、トナー受像層としては、特許第２７８８３５８号明細書、特開平７−２４８６３７号、同８−３０５０６７号、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。
【０１２０】
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。
【０１２１】
前記トナー受像層としては、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、トナー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。
【０１２２】
尚、前記支持体に対し、トナー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。
【０１２３】
［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。
【０１２４】
−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、前記トナー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、前記トナー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、トナー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。
【０１２５】
前記表面保護層には、トナー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。
【０１２６】
−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、トナー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、バック層の構成がトナー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。
【０１２７】
−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、支持体及びトナー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、該密着改良層及びトナー受像層の間に、更にクッション層等を設けるのが好ましい。
【０１２８】
−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、クッション層及びトナー受像層の間、トナー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、トナー受像層、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、支持体及びトナー受像層の間に存在させることができる。
【０１２９】
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。
【０１３０】
＜トナー＞
本発明の電子写真用受像シートの画像形成方法は、印刷又は複写の際に、トナー受像層にトナーを受容させる。
前記トナーは、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。
【０１３１】
−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、特に本発明のトナー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。
【０１３２】
−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。
【０１３３】
−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。
【０１３４】
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。
【０１３５】
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。
【０１３６】
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、前記の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。
【０１３７】
−トナー その他の成分−
また、本発明のトナーには、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。
【０１３８】
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。
【０１３９】
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。
【０１４０】
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。
【０１４１】
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、これらの金属塩等の粉末、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。
【０１４２】
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得られるものが好ましい。
【０１４３】
−トナー物性等−
本発明の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きすぎると、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、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×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。
【０１４４】
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。
【０１４５】
＜画像形成方法＞
本発明の画像形成方法は、第１の態様として、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の該画像形成面を、定着ベルト及び定着ローラにより、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。
また、本発明の画像形成方法は、第２の態様として、前記電子写真用受像シートに、トナー画像を形成した後、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、定着ベルト及び定着ローラにより、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。
【０１４６】
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電子写真用受像シート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、電子写真用受像シート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は使用される。
【０１４７】
本発明の電子写真用受像シートは、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、少なくとも、トナーを溶融し、加圧し得る加熱加圧部と、トナーの付着した電子写真用受像シートをトナー受像層と接する状態で搬送することができる定着ベルトと、任意に、加熱した電子写真用受像シート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とを有するベルト方式のトナー定着部を有する電子写真装置が挙げられる。このような定着ベルトを有する電子写真装置にトナー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、トナー受像層に付着したトナーが、電子写真用受像シート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、トナー受像層にトナーが完全に埋め込まれた状態でトナー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。
【０１４８】
本発明で形成される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。
【０１４９】
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る方法が好ましい。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。
【０１５０】
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。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。
【０１５１】
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トナー受像層における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トナー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℃以上が好ましい。
【０１５２】
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)が付着した受像シート(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)のトナー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。
【０１５３】
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トナー受像層表面の温度を意味し、例えば、８０〜１９０℃、より好ましくは、１００〜１７０℃である。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トナー受像層表面の圧力を意味し、例えば、１〜１０ｋｇ／ｃｍ²、より好ましくは、２〜７ｋｇ／ｃｍ²である。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、トナー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、トナー受像層表面に移動する。移動してきた離型剤は、トナー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、トナー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、トナー受像層表面に形成された離型剤の層(膜)が冷却・固化し、トナー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。
【０１５４】
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。
【０１５５】
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。
【０１５６】
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。
【０１５７】
【化１】

【０１５８】
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。
【０１５９】
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。
【０１６０】
【化２】

【０１６１】
前記（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。
【０１６２】
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。
【０１６３】
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。
【０１６４】
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。
【０１６５】
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。
【０１６６】
【化３】

【０１６７】
前記（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。
【０１６８】
前記（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。
【０１６９】
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。
【０１７０】
前記本発明の定着用ベルトは、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℃、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。
【０１７１】
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。
【０１７２】
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電子写真方法であれば、上記、特に図１に示した方法に制限されるものではない。通常の電子写真法であれば、いずれも適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には、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。
【０１７３】
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。
【０１７４】
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、電子写真用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。
【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、以下の実施例及び比較例において、「％」及び「部」は、それぞれ「質量％」及び「質量部」を表す。
【０１７６】
（実施例１）
−コア／シェル型ラテックス粒子の水分散液の調製−
シード法により、コア／シェル型ラテックス粒子の水分散液を調製した。シードポリマーとして、アクリル酸２−エチルヘキシル（ＥＨＡ）と、メタクリル酸メチル（ＭＭＡ）とを、質量比で、９５対５の割合で共重合体して得られた共重合体（数平均分子量（Ｍｎ）＝１１０００）（平均粒径０．０６μｍ）を含有するエマルジョンに、メタクリル酸メチル（ＭＭＡ）、アクリル酸ブチル（ＢＡ）及びメタクリル酸（ＭＡＡ）を、質量比で、６７対２３対１０の割合で添加し、重合開始剤として、過硫酸アンモニウムを配合して、６０℃で、重合を開始させ、Ｍｎ＝６７００で、平均粒径０．０８μｍのコア／シェル型ラテックス粒子の水分散液（固形分含量３０％）を得た。
【０１７７】
（実施例２〜５及び比較例１〜１１）
実施例１と同様にして、実施例２〜５及び比較例１〜１１のコア／シェル型ラテックス粒子の水分散液（固形分含量３０％）を得た。得られたコア／シェル型ラテックス粒子の特性を、以下の表１，２に示した。併せて、得られた水分散液の粘度及び表面張力の値も記載した。
【０１７８】
（比較例１２）
この比較例１２は、乳化剤を使用してコア／シェル型ラテックス粒子の水分散液を調製した例を示す。
第一段階として、アクリル酸２−エチルヘキシル（ＥＨＡ）９％、メタクリル酸メチル（ＭＭＡ）５％、陰イオン界面活性剤としてドデシルベンゼンスルホン酸ナトリウム２％、及び開始剤として過硫酸アンモニウムを配合して重合を開始させ、第二段階として、メタクリル酸メチル（ＭＭＡ）６７％及びアクリル酸ブチル（ＢＡ）２３％を添加し、更に重合を進め、コアのＭｎ（ｃ）が１１０００で、シェルのＭｎ（ｓ）が６７００のコア／シェル型ラテックスの水分散液（固形分含量３０％）を得た。
得られたコア／シェル型ラテックス粒子の特性を、以下の表１，２に示した。併せて、得られた水分散液の粘度及び表面張力の値も記載した。
【０１７９】
−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。
添加剤の種類 量（％）
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
エポキシ化脂肪酸アミド（ＥＦＡ） ０．２
ポリアミドポリアミンエピクロルヒドリン ０．３
注）ＡＫＤは、アルキルケテンダイマー（アルキル部分は、ベヘン酸を主体とする脂肪酸に由来する）を意味し、ＥＦＡは、エポキシ化脂肪酸アミド（脂肪酸部分は、ベヘン酸を主体とする脂肪酸に由来する）を意味する。
【０１８０】
得られたパルプ紙料を、長網抄紙機により坪量１５０ｇ／ｍ^２の原紙を作製した。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、ＰＶＡ １．０ｇ／ｍ^２、ＣａＣｌ_２ ０．８ｇ／ｍ^２を付着した。
抄紙工程の最後で、ソフトカレンダーを用いて、密度を１．０１ｇ／ｃｍ^３に調整した。得られた基紙において、トナー受像層が設けられる側において、金属ロールが接するように通紙し、金属ロールの表面温度は１４０℃であった。
【０１８１】
−トナー受像層用の調製−
実施例１〜５及び比較例１〜１２のコア／シェル型ラテックス粒子の水分散液を、上記基紙支持体の表面（トナー受像層を形成する側）に、バーコーターにより塗工した。塗布量は、乾燥質量１２gであった。
【０１８２】
−バック層用塗布液の調製−
下記の成分を混合し、攪拌して、バック層用の塗布液を調製した。
アクリル樹脂水分散物
(固形分３０％、ハイロスXBH-997L、星光化学製) １００．０ｇ
マット剤
（テクポマーMBX-12、積水化成品工業製) ５．０ｇ
離型剤(ハイドリンD337、中京油脂製) １０．０ｇ
増粘剤(CMC) ２．０ｇ
アニオン界面活性剤(AOT) ０．５ｇ
イオン交換水 ８０ｍｌ
【０１８３】
バック層用の塗布液の粘度は、３５ｍＰａ・ｓであり、表面張力は、３３ｍＮ／ｍであった。
【０１８４】
−バック層の塗工−
支持体の裏面には、上記バック層用の塗布液を、上記トナー受像層用の場合と同様に、バーコーターで塗布した。塗布量は、乾燥質量で９ｇ／ｍ^２であった。トナー受像層及びバック層は、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４０℃に保温した状態で、圧力１４７ｋＮ／ｍ（１５ｋｇｆ／ｃｍ）にて行った。
【０１８５】
＜電子写真用受像シートの物性の評価＞
前記各実施例及び比較例に従って製造された電子写真用受像シートに、図１に示す定着ベルト方式の電子写真装置を用いて画像を形成し、耐接着性、ひび割れ性、光沢度及びオフセット性を測定した。結果を表３に示す。
【０１８６】
プリント用画像として、白ベタ、グレー（画像のＲ＝Ｇ＝Ｂ＝５０％）、黒(１００％)、及び女性のポートレイト画像を使用した。電子写真装置としては、下記定着ベルトを有する装置を用いたことを除いて、富士ゼロックス製カラーレーザープリンター（Ｃ−２２２０）を用いた。
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。
【０１８７】
この定着ベルト系においては、定着ベルト（１３）の搬送速度は、３０ｍｍ／秒であり、加熱ローラ（１４）と加圧ローラ（１５）との間のニップ圧力は、０．２ＭＰａ（２ｋｇｆ／ｃｍ^２）であり、加熱ローラ（１４）の設定温度は、１５５℃であり、これが定着温度に相当する。なお、加圧ローラ（１５）の設定温度は、１３０℃であった。電子写真用受像シートは、定着ベルト（１３）から剥離する時点で６０℃以下に冷却されていた。
この装置を使用して、電子写真用受像シートに上記ポートレイト画像及び白ベタ、グレー、黒の５ｃｍ角のパターンを転写した。
【０１８８】
＜＜耐接着性＞＞
得られた電子写真用受像シートを、４０℃、８０％ＲＨに２４時間調整した後、トナー受像面を対向させて重ね合わせ、３．５ｃｍ□（Ａｃｍ□は、タテ×ヨコそれぞれＡｃｍを意味する。）×５００ｇの加重を加え、同一環境下で７日間放置した後、電子写真用受像シートを引き離す際の状態を観察し、以下の評価基準に従って評価した。
〔評価基準〕
１：剥離音及び接着跡ともになし。
２：軽微な剥離音又は接着跡がある。
３：接着跡が１／４未満。
４：接着跡が１／４以上〜１／２未満。
５：接着跡が１／２以上。
【０１８９】
＜＜ひび割れ性＞＞
富士ゼロックス（株）製のカラーレーザープリンターＣ−２２２０を使用し（但し、定着部を前述のベルト定着方式に変更した）、黒色の最大濃度で均一１０ｃｍ□の画像を絵出しする。１０℃、１５％ＲＨ環境下で１日間放置する。１、２、３、４及び５ｃｍ径の丸棒を用意し、画像面が、外側になるように大径の棒から順次小径の棒に巻き付け、ひび割れの発生状態を観察し、ひび割れの発生する径を記録する。
【０１９０】
＜＜光沢度（％）＞＞
富士ゼロックス（株）製のカラーレーザープリンターＣ−２２２０を使用し（但し、定着部を前述のベルト定着方式に変更した）、黒／白条件下で、濃度を６段階（０、２０、４０、６０、８０及び１００％）に１０ｃｍ□の画像を絵出しする。この６段階部分を、ＪＩＳ Ｚ ８７４１、デジタル変角光沢度計（スガ試験機製、ＵＧＶ−５Ｄ）、４５度測定で測定し、その最小値を記録する。
【０１９１】
＜＜オフセット性＞＞
富士ゼロックス（株）製のカラーレーザープリンターＣ−２２２０（オイルレス定着方式）を使用し、３０℃、８０％ＲＨ環境下で定着部を正常に通過し、かつ画像面に生じる貝殻状のムラの状態を、以下の評価基準に従って評価する。
〔評価基準〕
○：無い
△：やや発生
×：多く発生
【０１９２】
【表１】

注１）×１０^３
注２）コア／シェル型ラテックス粒子におけるシェル又はコアの比率（質量）
【０１９３】
【表２】

【０１９４】
【表３】

【０１９５】
なお、市販のカラーレーザープリンター、具体的には、富士ゼロックス製フルカラーレーザープリンター（ＤＣＣ−４００ＣＰ／３２０ＣＰ、ＤＣＣ−５００ＣＰ）にてプリントしたところ、いずれのサンプルも通紙でき、表３と同様の結果が得られた。
【０１９６】
【発明の効果】
以上説明したように、本発明によれば、支持体に塗工される水分散液中のコア／シェル型ラテックス粒子が、乳化剤を使用しないで合成され、かつ、（１）コアの数平均分子量〔Ｍｎ（ｃ）〕と、シェルの数平均分子量〔Ｍｎ（ｓ）〕とが、Ｍｎ（ｃ）＞Ｍｎ（ｓ）を満たし、（２）前記コアの数平均分子量〔Ｍｎ（ｃ）〕が、３００００〜５０００００であり、（３）前記シェルの数平均分子量〔Ｍｎ（ｓ）〕が、４０００〜３００００であり、（４）前記コア対前記シェルの質量比が、１０：９０〜９０：１０であり、そして（５）前記ラテックス粒子の平均径が、０．２μｍ以下であると、得られる水分散液を、簡易に塗工することにより、耐オフセット性と、ひび割れ防止性とを同時に改善された電子写真用受像シートを製造するできることが分かる。
【図面の簡単な説明】
【図１】図１は、本発明の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。
【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 1. Field of the Invention The present invention relates to an aqueous dispersion of core / shell type latex particles used for an electrophotographic toner image-receiving layer, and in particular, an electrophotographic image-receiving sheet having improved image quality or offset resistance and crack prevention properties at the same time. In particular, the present invention relates to an aqueous dispersion of core / shell type latex particles used for producing an image, an electrophotographic image-receiving sheet using the aqueous dispersion, a production method thereof, and an image forming method.
[0002]
[Prior art]
The electrophotographic method is widely used as an output device of a copying machine or a personal computer because it is dry processing, has an excellent printing speed, and can output onto general-purpose paper such as plain paper or high-quality paper.
In the electrophotographic image receiving sheet, the toner image receiving layer is formed by various methods. For example, a method of laminating a thermoplastic resin on a support such as a base paper by melt extrusion, a method of applying a resin solution to the support, and the like have been proposed.
Among these techniques, the method of applying a water-based polymer resin solution has been widely studied in recent years because it has a low burden on the global environment and the material itself is inexpensive.
[0003]
However, since the aqueous polymer resin solution is usually subjected to emulsion polymerization using an emulsifier (surfactant), the emulsifier remains particularly on the surface of the obtained emulsion polymerization resin. For this reason, the toner image-receiving layer prepared from the obtained emulsion polymerization resin composition is greatly affected by the environmental humidity due to the presence of the emulsifier, and the toner image-receiving layer has adhesiveness under a high temperature and high humidity environment. Therefore, when the electrophotographic image-receiving sheet is laminated and stored, the toner image-receiving layer of the electrophotographic image-receiving sheet located below adheres to the support of the electrophotographic image-receiving sheet located thereon. In the case where block king is caused or the fixing process is performed in an oil-less manner, an offset phenomenon occurs or becomes a problem. On the other hand, in a low-temperature and low-humidity environment, the toner image-receiving layer dries and cracks, and when image fixing processing is performed thereafter, there is a problem that the image quality deteriorates based on the undulations of the cracks.
[0004]
By the way, Patent Document 1 discloses an aqueous toner receptive core / shell latex composition.
However, the core / shell latex particles used in Patent Document 1 can prevent block king and cracking to some extent by using the core / shell structure. Since the core / shell type latex particles are prepared using an emulsifier, the resulting toner image-receiving layer will still be affected by environmental humidity. Further, in the technology of Patent Document 1, since the particle size of the core / shell type latex particles, the molecular weight of the resin constituting the core or the shell, etc. are not studied, in this technology, crack prevention property, full color image quality, In particular, it is difficult to achieve offset prevention in oilless system fixing to a satisfactory level at the same time.
[0005]
[Patent Document 1]
Japanese National Patent Publication No. 10-509253
[0006]
[Problems to be solved by the invention]
An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the first object of the present invention is to provide an electrophotographic image-receiving sheet capable of simultaneously achieving both offset prevention and crack prevention in an electrophotographic image forming method or apparatus for forming a full color image by an oilless fixing method. It is an object of the present invention to provide an aqueous dispersion of core / shell type latex particles that are used to produce the above.
The second object of the present invention is to provide a method of forming an electrophotographic image receiving sheet using such an aqueous dispersion of core / shell type latex particles, and an electrophotographic image receiving sheet obtained thereby. It is to provide.
The third object of the present invention is to realize stable paper feeding without offsetting to the fixing roller and the fixing belt even when an oilless machine without fixing oil is used. It is an object of the present invention to provide an image forming method capable of forming a good image having gloss and rich in photographic feeling.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be achieved by using an aqueous dispersion of core / shell type latex particles having the following configuration. Is. The present invention has been made based on such novel findings.
[0008]
  That is, means for solving the above-described problems are as follows.
<1> An aqueous dispersion of core / shell type latex particles used for an electrophotographic toner image-receiving layer,
The core / shell type latex particles are synthesized without using an emulsifier,
The core / shell type latex particles satisfy the following characteristics (1) to (5): an aqueous dispersion of core / shell type latex particles used for an electrophotographic toner image-receiving layer.
(1) The number average molecular weight [Mn (c)] of the core and the number average molecular weight [(Mn (s)] of the shell have the following relationship:
Mn (c)> Mn (s)
(2) The number average molecular weight [Mn (c)] of the core is 30,000 to 500,000.
(3) The number average molecular weight [Mn (s)] of the shell is 4000-30000.
(4) The mass ratio of the core to the shell is 10:90 to 90:10
(5) The average diameter of the latex particles is 0.2 μm or less.
<2> The aqueous dispersion according to <1>, wherein the glass transition temperature [Tg (s)] of the shell is 30 to 100 ° C.
<3> When the glass transition temperature [Tg (c)] of the core is calculated by the following Dimarzio equation, the glass transition temperature [Tg (t)] of the latex particles composed of the core / shell is 10 ° C. or less. The aqueous dispersion according to <1> or <2>, wherein the aqueous dispersion is Tg.
1 / Tg (t) = w (c) / Tg (c) + w (s) / Tg (s)
(Where Tg (t) is the Tg at the absolute temperature of the latex particles, Tg (c) is the Tg at the absolute temperature of the core, and Tg (s) isAbsolute temperatureTg, w (c) is the mass ratio of the core in the latex particles, and w (s) is the mass ratio of the shell in the latex particles. )
<4> An electrophotographic image-receiving sheet comprising a support and a toner image-receiving layer provided on at least one surface of the support, wherein the toner image-receiving layer is any one of <1> to <3> An electrophotographic image-receiving sheet, which is formed from the aqueous dispersion of the core / shell type latex particles described above.
<5> The electrophotographic image-receiving sheet according to <4>, wherein the toner image-receiving layer contains a natural wax, and the natural wax is at least one of a plant wax and a mineral wax.
<6> The electrophotographic image-receiving sheet according to <5>, wherein the plant-based wax is carnauba wax having a melting point of 70 to 95 ° C.
<7> The electrophotographic image-receiving sheet according to <5>, wherein the mineral wax is a montan wax having a melting point of 70 to 95 ° C.
<8> The electrophotographic image-receiving sheet according to any one of <4> to <7>, wherein the support is selected from a base paper, a synthetic paper, a synthetic resin sheet, a coated paper, and a laminated paper.
<9>A method for producing the electrophotographic image-receiving sheet according to any one of <4> to <8>, wherein the aqueous dispersion according to any one of <1> to <3> is provided on the support. The electrophotographic image-receiving sheet is produced by applying the above.
<10>The method for producing an electrophotographic image-receiving sheet according to <9>, wherein the viscosity of the aqueous dispersion is 10 mPa · s or more.
<11>The method for producing an electrophotographic image-receiving sheet according to <9> or <10>, wherein the aqueous dispersion has a surface tension of 50 mN / m or less.
<12>The method for producing an electrophotographic image-receiving sheet according to any one of <9> to <11>, wherein the aqueous dispersion is applied and then calendered.
<13>The image forming method for forming an image on the electrophotographic image-receiving sheet according to any one of <4> to <8>, wherein the toner received in the toner image-receiving layer contains at least a binder resin and a colorant. And the toner has a volume average particle diameter of 0.5 μm or more and 10 μm or less. An image forming method having a volume average particle size distribution index (GSDv) of 1.3 or less.
<14>The image forming method according to <13>, wherein in the toner, a ratio (GSDv / GSDn) of a volume average particle size distribution index (GSDv) to a number average particle size distribution index (GSDn) is at least 0.95.
<15>The toner received in the toner image-receiving layer contains at least a binder resin and a colorant, the volume average particle diameter of the toner is 0.5 μm or more and 10 μm or less, and the average value of the shape factor represented by the following formula is The image forming method according to <13> or <14>, wherein the image forming method is 1.00 to 1.50.
Shape factor = (π × L ² ) / (4 × S)
(However, L represents the maximum length of toner particles, and S represents the projected area of toner particles.)
<16>The toner to be received in the toner image-receiving layer is at least (i) 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 the adhered particles; and (iii) a step of heating and fusing the attached particles to form toner particles. The image forming method according to any one of <13> to <15>, which is obtained by a method for producing a toner including.
<17> From the above <4><8>An oilless method for forming an image using the electrophotographic image-receiving sheet according to any one of the above, wherein after the toner image is formed on the electrophotographic image-receiving sheet, the electrophotographic image-receiving sheet In the image forming method, the image forming surface is heated and pressed by a fixing belt and a fixing roller, cooled, and then peeled off from the fixing belt.
<18> From <4> above<8>A method of forming an image by an oil-less method using the electrophotographic image-receiving sheet according to any one of the above, wherein after forming a toner image on the electrophotographic image-receiving sheet and fixing with a heat roller, In the image forming method, the image forming surface of the electrophotographic image receiving sheet is heated and pressed by a fixing belt and a fixing roller, cooled, and then peeled off from the fixing belt.
<19> The above <17> or <18, wherein the formed toner image is cooled to a state below the softening point of a binder resin used for the toner or a glass transition point + 10 ° C. or less and then peeled off from the belt-shaped fixing member. >.
<20> The image forming method according to any one of <17> to <19>, wherein a fluorocarbon siloxane rubber layer having a uniform thickness is provided on a surface of the fixing belt.
<21> The above <17> to <19>, 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. The image forming method according to any one of the above.
<22> The image forming method according to <20> or <21>, wherein the fluorocarbon siloxane rubber has a perfluoroalkyl ether group and / or a perfluoroalkyl group in a main chain.
[0009]
The electrophotographic image-receiving sheet of the present invention is synthesized without using the above-mentioned emulsifier, and by applying an aqueous dispersion of core / shell type latex particles having predetermined characteristics on the support, it is capable of preventing offset and preventing cracks. The image can be achieved at the same time, has an unprecedented glossiness, and has a good photographic feel.
[0010]
The image forming method of the present invention uses the electrophotographic image receiving sheet of the present invention, forms a toner image on the electrophotographic image receiving sheet, and then fixes the image forming surface of the electrophotographic image receiving sheet. After being heated and pressed by a belt and a fixing roller, cooled, and then peeled off from the fixing belt. As a result, even if an oilless machine without fixing oil is used, offset of the image receiving sheet and toner component can be prevented by improving the peelability of the image receiving sheet and toner, and stable paper feeding can be realized. It is possible to realize a good image having an unprecedented good glossiness and rich in photographic feeling.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
<Aqueous dispersion of core / shell type latex particles>
The aqueous dispersion of the core / shell type latex particles of the present invention is synthesized without using an emulsifier, and the core / shell type latex particles contained in the aqueous dispersion have the following characteristics (1) to (5). To meet.
(1) The number average molecular weight [Mn (c)] of the core and the number average molecular weight [(Mn (s)] of the shell have the following relationship.
Mn (c)> Mn (s)
(2) The core has a number average molecular weight [Mn (c)] of 30,000 to 500,000.
(3) The number average molecular weight [Mn (s)] of the shell is 4000-30000.
(4) The mass ratio of the core to the shell is 10:90 to 90:10. (5) The average diameter of the latex particles is 0.2 μm or less.
[0012]
As a method for producing the core / shell type latex particles contained in the aqueous dispersion of the present invention, various production methods can be used. The core / shell type latex particles obtained by an emulsion polymerization method that does not use such an emulsifier (surfactant) are generally called “soap-free latex” (for example, “synthesis and design of acrylic resin”). New application development "(Chubu Management Development Center Publishing Department, issued July 1, 1985), pages 279-281).
Examples of a method for producing such soap-free latex include a seed method, a reactive emulsifier method, and an oligomer method.
The seed method is a method in which a water-soluble or water-dispersible polymer is prepared in advance, a monomer is added as a seed polymer, and polymerization is performed.
In the seed method, usually, a seed polymer forms a core part, and a polymerized polymer forms a shell part according to polymerization of a monomer to form a core / shell structure.
[0013]
The reactive emulsifier method is a method in which a compound (reactive emulsifier) having an ethylenically unsaturated bond and an anionic or nonionic hydrophilic group in the molecule is used in the same manner as a conventional emulsifier. However, the reactive emulsifier used is taken into the polymer to be produced and does not remain as an emulsifier.
As the reactive emulsifier, various reactive emulsifiers are known, and acrylic acid derivatives (JP 55-11252, JP 56-28208, etc.) and itaconic acid derivatives (JP 51-51). No. -30284), maleic acid derivatives (Japanese Patent Laid-Open No. 51-30284, Japanese Patent Publication No. 56-29657, etc.), fumaric acid derivatives (Japanese Patent Laid-Open No. 51-30285, Japanese Patent Laid-Open No. 51-30284). Publication etc.).
[0014]
Hereinafter, the method for producing the core / shell type latex resin composition of the present invention will be briefly described by taking the seed method as an example.
As a seed polymer suitable for producing the core / shell type latex resin composition of the present invention, a seed polymer prepared by any of an emulsion polymerization method, a suspension polymerization method and a dispersion polymerization method may be used. it can. Among these, it is appropriate to use a seed polymer prepared by an emulsion polymerization method. Even if an emulsifier is used in the emulsion polymerization method, the amount of the emulsifier can be greatly reduced by the separation and purification process. Further, even if the seed polymer contains an emulsifier, the seed polymer is taken into the core / shell structure and does not exist on the surface of the core / shell structure, so that it is hardly affected by humidity. On the other hand, for the seed polymer prepared by the suspension polymerization method or the dispersion polymerization method, a complicated process for removing the dispersant, the solvent and the like is required.
As the seed polymer, specifically, a water-soluble polymer is suitable, for example, polyacrylate, copolymers thereof, gelatin, tragacanth gum, starch, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, Polyvinyl pyrrolidone and the like can be used.
[0015]
In the seed method, as the monomer to be added in the presence of the seed polymer, various ethylenically unsaturated monomers can be used as long as they can be radically polymerized. In this case, the monomer may be the same as or different from the monomer used to produce the seed polymer. Examples of such monomers include (meth) acrylic acid ester monomers, monovinyl aromatic monomers, (meth) vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers, and halogenated olefin monomers. Preferred examples include monomers and polyvinyl monomers.
[0016]
Examples of the (meth) acrylic monomer include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylate-2-ethylhexyl, (meth) Cyclohexyl acrylate, phenyl (meth) acrylate, methyl (meth) acrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like Preferable examples include a mixture.
Examples of the vinyl aromatic monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p. -Butylstyrene, pt-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-decylstyrene, p-dodecylstyrene, 2,4-dimethylstyrene, 3,4-dichlorostyrene And the like, or a styrene monomer or a derivative thereof, or a mixture thereof.
[0017]
Examples of the vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, and vinyl phenyl ether.
Examples of the olefin monomer include ethylene, monoolefin monomers such as propylene, isobutylene, 1-butene, 1-pentene and 4-methyl-1-pentene, and diolefin monomers such as butadiene, isoprene and chloroprene. It is done.
Furthermore, a crosslinkable monomer may be added to improve the properties of the seed polymer. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.
[0018]
In the seed method, a radical polymerization initiator can be used. The polymerization initiator can be appropriately used as long as it is water-soluble. Examples of such a polymerization initiator include persulfates (potassium persulfate, ammonium persulfate, etc.) and azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis). (2-amidinopropane) salts), peroxide compounds, and the like are preferable.
[0019]
Furthermore, the said polymerization initiator is good also as a redox-type initiator combined with a reducing agent as needed. By using a redox initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be further shortened.
Any temperature may be selected as long as the polymerization temperature is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but for example, a range of 50 to 80 ° C. is usually used. However, it is also possible to perform polymerization at room temperature or lower by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).
[0020]
The core / shell type latex particles obtained as described above have the characteristic properties described above.
In the core / shell type latex particles of the present invention, the number average molecular weight [(Mn (c)) of the core and the number average molecular weight [Mn (s)] of the shell have the following relationship.
Mn (c)> Mn (s)
[0021]
Preferably, Mn (c) is 5000 larger than Mn (s), more preferably 10,000. By providing such a molecular weight difference, the characteristics of the core / shell type latex particles can be utilized, and both blocking prevention (non-adhesiveness) and crack prevention can be achieved.
When Mn (c) is set to be larger than Mn (s), it is possible to make use of the characteristics of the core / shell structure and achieve both offset prevention and crack prevention under the high temperature and high humidity conditions of the obtained toner image receiving layer. it can.
In the core / shell type latex particles of the present invention, the core has a number average molecular weight [(Mn (c)) of 30,000 to 500,000, preferably 40000 to 400,000. If the core Mn (c) is less than 30000, cracking prevention properties deteriorate, while if it exceeds 500000, the storage elastic modulus (G ′) at 130 ° C. increases and the image quality deteriorates. .
On the other hand, the number average molecular weight [Mn (s)] of the shell is suitably 4000-30000, preferably 5000-20000. When the Mn (s) of the shell is less than 4000, the crack prevention property is lowered and the image quality such as the glossiness tends to be lowered. On the other hand, when it exceeds 30000, the image quality is lowered, which is not preferable.
[0022]
In the core / shell type latex particles, the mass ratio of the core to the shell is suitably 10:90 to 90:10, preferably 20:80 to 80:20. When the mass ratio of the core to the shell is out of this range, it is difficult to fully exhibit the characteristics of the core / shell structure, and the characteristics are similar to those of a simple continuous film.
The core / shell type latex particles have an average particle size of 0.2 μm or less, preferably 0.1 μm or less. The lower limit of the average particle diameter is preferably about 0.04 μm, for example.
When the average particle diameter exceeds 0.2 μm, the characteristics of the core / shell structure cannot be utilized.
[0023]
  In the core / shell type latex particles, the Tg (s) of the shell is preferably 30 to 100 ° C., more preferably 40 to 80 ° C. When the Tg (s) of the shell is less than 30 ° C., the adhesion resistance tends to be lowered. On the other hand, when the Tg exceeds 100 ° C., the image quality is liable to deteriorate.
  The Tg (c) of the core is preferably Tg at which the Tg (t) of the latex particles composed of the core / shell is 10 ° C. or less when calculated by the following Dimarzio equation.
1 / Tg (t) = w (c) / Tg (c) + w (s) / Tg (s)
(Where Tg (t) is Tg in terms of absolute temperature of latex particles, Tg (c) is Tg in terms of absolute temperature of core, and Tg (s) isAbsolute temperature displayTg, w (c) is the mass ratio of the core in the latex particles, and w (s) is the mass ratio of the shell in the latex particles. In general, this equation is used for calculating the Tg of the copolymer, but it can also be applied to a core-shell latex having a particle size of 0.5 μm or less. )
  When the Tg (c) of the core is Tg (t) of the latex particles exceeding 10 ° C. in the above-mentioned Dimargio formula, the crack preventing property tends to be lowered, which is not preferable.
[0024]
The storage elastic modulus at 130 ° C. of the core / shell type latex particles is preferably 5 × 10²~ 5x10⁴Pa, particularly preferably 7 × 10²~ 1x10⁴It is appropriate to use Pa. This storage modulus is 5 × 10²If it is less than Pa, the anti-offset property to the fixing roll is lowered, which is not preferable. On the other hand, the storage elastic modulus is 5 × 10⁴If it exceeds Pa, the image quality is likely to deteriorate, which is not preferable. The core / shell type latex particles of the present invention are used in the form of an aqueous dispersion. Therefore, environmental problems encountered when using organic solvents and problems in the working environment are reduced.
The core / shell type latex particles are suitably used in the range of, for example, 10 to 60% by mass, preferably 20 to 50% by mass, based on the mass of the aqueous dispersion.
In the aqueous dispersion of the present invention, if necessary, for example, a matting agent, a pigment, a plasticizer, a release agent, a lubricant, a thickener, an antistatic agent, a fluorescent whitening agent, a color adjusting dye, etc. These various additives can be arbitrarily blended.
[0025]
<Electrophotographic image-receiving sheet>
The electrophotographic image-receiving sheet has a support and a toner image-receiving layer provided on at least one surface of the support, and other layers appropriately selected as necessary, for example, a surface protective layer, an intermediate layer, an undercoat A layer, a cushion layer, a charge control (prevention) layer, a reflection layer, a tint preparation layer, a storage stability improving layer, an adhesion prevention layer, an anti-curl layer, and a smoothing layer. Each of these layers may have a single layer structure or a laminated structure.
[0026]
[Support]
As the support used for the electrophotographic image-receiving sheet of the present invention, various supports can be used as long as they can be used for the electrophotographic image-receiving sheet.
Such a support may be selected from various materials as long as it can withstand the fixing temperature and satisfies requirements in terms of smoothness, whiteness, slipperiness, friction, antistatic properties, and the like. Can do.
The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof 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.
[0027]
-Base paper-
As raw materials for the base paper (including synthetic paper), those used for known base paper as those used for the support can be selected from various materials without particular limitation. 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.
[0028]
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.
[0029]
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 further higher fatty acids such as alkyl ketene dimer, alkenyl succinic anhydride (ASA) and epoxidized fatty acid amide. Examples thereof include compounds.
[0030]
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).
[0031]
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.
[0032]
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.
[0033]
The base paper as described above is a ratio (Ea / Eb) of the longitudinal Young's modulus (Ea) and the lateral Young's modulus (Eb) in terms of improving the rigidity and dimensional stability (curlability) of the electrophotographic image-receiving sheet. ) 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 sheet are liable to be deteriorated, and the running property during conveyance is hindered. Absent.
[0034]
In the present invention, the Wangken smoothness of the surface of the base paper on the toner image-receiving layer side 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.
In the present invention, the object of the present invention is achieved by employing 210 seconds or more, which is a much larger Oken-type smoothness than the conventionally adopted Oken-type smoothness.
Here, the Oken-type smoothness is measured according to JAPAN TAPPI No. 5 Smoothness defined by the B method.
[0035]
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 from paper is an important factor that represents the degree 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]
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
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.
[0040]
-Synthetic resin sheet-
Examples of the synthetic resin sheet (film) include those obtained by molding a synthetic resin into a sheet shape. For example, a polyolefin resin such as a polypropylene resin or a polyester resin such as a polyethylene terephthalate resin is extruded into a sheet shape. Obtained by.
[0041]
-Coated paper-
The coated paper is a paper or sheet obtained by coating various types 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.
The thickness of the thermoplastic resin layer is preferably 5 to 100 μm, and more preferably 15 to 50 μm. The thermoplastic resin layer provided on the front surface and the thermoplastic resin layer provided on the back surface may be the same or different in terms of components, physical properties, thickness, and configuration.
[0042]
It is appropriate to use a thermoplastic resin as the resin applied to the surface of the base paper or the like. Examples of such a thermoplastic resin include the following thermoplastic resins (a) to (h).
[0043]
(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, 63-7773, 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.
[0044]
(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 resin, ethyl cellulose resin, cellulose acetate resin, etc., 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.
[0045]
-Laminated paper-
The laminated paper is obtained by laminating various resins, rubber or polymer sheets or films on a sheet such as a base paper. Examples of the material to be laminated 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.
[0046]
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.
[0047]
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.
[0048]
The resin to be coated or laminated is not limited to a thermoplastic resin, for example, a monomer, a resin obtained by reacting a thermoplastic resin with heat, light, a hardening agent, a crosslinking agent, or the like. A thermosetting resin may be used.
[0049]
Further, at least one of the resin layers to be coated or laminated may be a monomer containing a photopolymerization initiator or a resin composition cured by ultraviolet irradiation.
Examples of the resin composition used in this case include those containing an electron beam curable organic compound as a main component. There is no restriction | limiting in particular in the kind of this electron beam curable organic compound. These may be monomers or oligomers. These may be used alone or in combination of two or more.
[0050]
The electron beam curable unsaturated compound can be selected from the following compounds, for example.
(1) Aliphatic, alicyclic or aromatic aliphatic 1- to 6-valent alcohols and polyalkylene glycol acrylate compounds
(2) Aliphatic, alicyclic, or aromatic aliphatic acrylate compounds obtained by adding alkylene oxide to 1-6 valent alcohols
(3) Polyacryloyl alkyl phosphate esters
(4) Reaction product of carboxylic acid, polyol and acrylic acid
(5) Reaction product of isocyanate, polyol and acrylic acid
(6) Reaction product of epoxy compound and acrylic acid
(7) Reaction product of epoxy compound, polyol and acrylic acid
[0051]
As these compounds, specifically, as an electron beam curable unsaturated organic compound, polyoxyethylene epichlorohydrin modified bisphenol A diacrylate, dicyclohexyl acrylate, epichlorohydrin modified polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, Hydroxybivalate ester neopentyl glycol diacrylate, nonylphenoxy polyethylene glycol acrylate, ethylene oxide modified phenoxylated phosphoric acid acrylate, ethylene oxide modified phthalic acid acrylate, polybutadiene acrylate, caprolactan modified tetrahydrofurfuryl acrylate, tris (acryloxyethyl) isocyan Nurate, trimethylolpropane triacrylate, pentae Thritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, polyethylene glycol diacrylate, 1,4-butadienediol diacrylate, neopentyl glycol diacrylate, and neopentyl glycol modified trimethylolpropane di An acrylate etc. can be mentioned.
In the present invention, these organic compounds can be used alone or in combination of two or more thereof.
[0052]
The resin layer to be coated or laminated is not particularly limited in the type of ultraviolet curable organic compound that is cured by ultraviolet irradiation. This ultraviolet curable resin composition is prepared by adding an appropriate amount of a photopolymerization initiator to the above-mentioned electron beam curable resin. In the present invention, the resin composition to be subjected to electron beam curing may contain a photopolymerization initiator or may not contain it, and is preferably used within a range in which no odor is generated.
[0053]
Examples of the photopolymerization initiator include known photopolymerization initiators such as ethyl anthraquinone, methyl benzoyl formate, 1-hydroxycyclohexyl phenyl ketone, antophenone, diethoxyacetophenone, and acetophenones such as trichloroacetophenone, o-benzoylmethylbenzoate, benzophenone, Michler ketone, benzyl, benzoin, benzoin alkyl ether, benzyldimethyl ketal, tetramethylthiuram monosulfide, xanthone, thioxanthones, benzophenones, and azo compounds. These photoinitiators may be used individually by 1 type, and may use 2 or more types together.
[0054]
The addition amount of the photopolymerization initiator is usually preferably about 0.1 to 10% by mass with respect to the mass of the ultraviolet curable resin. For example, it is preferable to use a known photopolymerization accelerator such as N-methyldiethanolamine or bisdiethylaminobenzophenone together with the photopolymerization initiator in order to improve the curing rate. The addition amount of the photopolymerization accelerator is not particularly limited as long as the effect is exhibited, but generally it is preferably 0.5 to 2 times the mass of the photopolymerization initiator.
[0055]
The electron beam accelerator used for the electron beam irradiation is not particularly limited, and for example, an electron beam irradiation apparatus such as a van de graff scanning method, a double scanning method, or a curtain beam method can be used.
[0056]
The ultraviolet irradiation apparatus used for the ultraviolet irradiation is not particularly limited, and for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, or the like can be used.
[0057]
As the support, a laminate may be formed by arbitrarily combining the various supports described above.
As a method for applying a resin or the like to the base paper or the like, for example, a method of applying, impregnating, or spraying a resin solution or a suspension or the like to the base paper can be preferably exemplified.
Corona discharge treatment, flame treatment, glow discharge treatment, or plasma on the both sides or one side of the base paper before coating or laminating for the purpose of improving the adhesion to the resin coated on the base paper etc. It is preferable to perform an activation process such as a process.
[0058]
For the purpose of improving the adhesion to the base paper, synthetic paper, synthetic resin sheet, or a layer on the sheet, such as a toner image receiving layer after providing a coat layer or a laminate layer, such as corona discharge treatment A surface treatment may be applied, or an undercoat layer may be applied to the surface.
The surface of the thermoplastic resin layer or the like used for the coated paper may have a glossy surface, or a fine surface, a matte surface, or a silky surface described in JP-A-55-26507, if necessary. Alternatively, the surface of the thermoplastic resin layer or the like on the side opposite to the side on which the conductive layer provided (if necessary) is formed may be matted with a matte surface. Further, these surfaces after being molded can be subjected to an activation treatment such as corona discharge treatment or flame treatment. After the activation treatment, a subbing treatment as described in JP-A-61-84443. Can also be done.
These may be used singly, or may be used in combination in any combination, such as after being subjected to an activation treatment or after being subjected to an activation treatment, or undercoating after a surface treatment such as an activation treatment. it can.
[0059]
In addition, various appropriately selected additives can be added to the thermoplastic resin layer and the like within a range that does not impair the object of the present invention.
[0060]
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 stiffnesses can be used according to the purpose, and the support for a photographic image receiving sheet for electrophotography is close to a support for color silver halide photography. Those are preferred.
[0061]
From the viewpoint of fixing performance, the support preferably has a thermal conductivity of, for example, 0.50 kcal / m · h · ° C. or higher at 20 ° C. and a relative humidity of 65%. Here, the thermal conductivity can be measured by a method described in JP-A-53-66279 using a transfer paper conditioned according to JIS P8111. The density of the support is 0.7 g / cm from the above viewpoint.³The above is preferable.
[0062]
Various additives appropriately selected can be blended in the support within a range that does not impair the object of the present invention. As such an additive, for example, a brightening agent, a conductive agent, a filler, a pigment such as titanium oxide, ultramarine, and carbon black, a dye, and the like can be contained as necessary.
[0063]
In the support, the front and back surfaces, and combinations thereof may be blended or coated with a hydrophilic binder, a semiconductive metal oxide such as alumina sol or tin oxide, carbon black, or other antistatic agents. Good. Specifically, a support described in JP-A-63-220246 can be used. The support preferably can withstand the fixing temperature, and can satisfy the requirements in terms of whiteness, slipperiness, friction, antistatic properties, dents after fixing, and the like.
[0064]
[Toner image receiving layer]
In the present invention, a toner image receiving layer is provided on at least one surface of the support. The toner image-receiving layer can be formed by applying an aqueous dispersion of core / shell latex particles.
The pigment content may be less than 40% by mass, preferably less than 30% by mass, particularly preferably less than 20% by mass, based on the mass of the core / shell latex particles constituting the toner image-receiving layer. it can. When the ratio of the pigment is large, blisters are easily generated, and there is a problem that the obtained toner image is rough.
In the present invention, an electrophotographic image-receiving sheet can be produced relatively easily by performing the toner image-receiving layer using an aqueous dispersion as described above. It is possible to allow the core / shell type latex particles to penetrate in the thickness direction.
[0065]
By applying the aqueous dispersion, a toner image-receiving layer is formed on the surface of the support, and at the same time, the core / shell type latex particles can be soaked in the thickness direction of the base paper. If the core / shell type latex particles permeate into the base paper at such a predetermined depth, the followability to heat between the base paper and the toner image receiving layer is improved, and cracking of the toner image receiving layer is prevented. And the anti-curling property of the electrophotographic image-receiving sheet is improved. Furthermore, if the penetration is large, the hygroscopicity of the base paper itself is lowered, and accordingly, the elongation due to the moisture absorption of the base paper is also reduced, and the curling property is further improved. In particular, when the back layer or the toner image receiving layer and the penetrating portion are provided on the back surface of the base paper using the core / shell type latex particles used for the toner image receiving layer provided on the surface of the base paper, the curling prevention is performed. The characteristics are greatly improved.
[0066]
The toner image-receiving layer used in the present invention receives the toner that forms an image from the developing drum or the intermediate transfer member by (static) electricity, pressure, etc. in the transfer process, and heat, pressure, etc. in the fixing process. And have the function of fixing.
The thickness of the toner image-receiving layer is suitably ½ or more, preferably 1 to 3 times the particle diameter of the toner used. The toner image receiving layer preferably has a thickness disclosed in JP-A-5-216322 and JP-A-7-301939. Specifically, the thickness is, for example, 3 to 50 μm, preferably 5 to 15 μm.
[0067]
The core / shell type latex particles used in the toner image-receiving layer of the present invention are preferably those that can satisfy the above-mentioned physical properties of the toner image-receiving layer in a state where the toner image-receiving layer is formed. More preferably, the resin alone may satisfy the preferable physical properties of the toner image receiving layer. Two or more resins having different physical properties can be used in combination.
As the core / shell type latex particles used in the toner image-receiving layer, those having a larger molecular weight than the thermoplastic resin used in the toner are preferably used. However, the molecular weight described above is not necessarily preferable depending on the relationship between the thermodynamic characteristics of the toner resin and the core / shell type latex particles used in the toner image-receiving layer. For example, when the softening temperature of the core / shell type latex particles used in the toner image receiving layer is higher than that of the toner resin, it is preferable that the molecular weight is the same or the core / shell type latex particles of the toner image receiving layer are smaller. There is.
[0068]
In addition to the core / shell type latex particles, various additives can be oriented in the toner image receiving layer used in the present invention for the purpose of improving the thermodynamic properties of the toner image receiving layer. Examples of such an additive include other additives such as a plasticizer, a slipping agent or a release agent, a matting agent, a coloring agent, a filler, a crosslinking agent, a charge control agent, an emulsion, and a dispersion.
[0069]
-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 toner 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-Theory and Application-" (edited by Koichi Murai, Koshobo), "Research on plasticizer" "Study under" (edited by Polymer Chemistry Association) and "Handbook Rubber and Plastic Compounded Chemicals" (edited by Rubber Digest Co., Ltd.).
[0070]
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.
[0071]
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 and 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, pentalin 4851, FK115, 4820, 830, Louisol 28-JA, picolastic A75, pico Examples include Tex LC and Crystallex 3085.
[0072]
The plasticizer relieves stress and strain (physical strain such as elastic force and viscosity, strain due to mass balance of molecules, binder main chain, pendant, etc.) generated when toner particles are embedded in the toner image receiving layer. Can be used arbitrarily to The plasticizer may be in a micro-dispersed state in the toner image-receiving layer, may be in a phase-separated microscopically in a sea-island shape, or may be in a sufficiently mixed and dissolved state with other components such as a binder.
The content of the plasticizer in the toner image-receiving layer is preferably 0.001 to 90% by mass, more preferably 0.1 to 60% by mass, and still more preferably 1 to 40% by mass.
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).
[0073]
-Slip agent and mold release agent-
The slipping agent or release agent that can be optionally used in the present invention is added for the purpose of preventing the electrophotographic image-receiving sheet of the present invention from adhering to the fixing heating member during fixing.
Examples of the slipping agent or the release agent include higher alkyl sodium sulfate, higher fatty acid higher alcohol ester, carbowax, higher alkyl phosphate ester, silicone compound, modified silicone, and curable silicone.
Polyolefin wax, fluorine oil, fluorine wax, carnauba wax, microcrystalline wax, and silane compound are also preferably used.
[0074]
Examples of the slipping agent or the release agent include US Pat. No. 2,882,157, US Pat. No. 3,212,060, US Pat. No. 3,850,640, French Patent No. 2180465, British Patents No. 955061, US Pat. No. 1,143,118, US Pat. No. 1,263,722, US Pat. No. 1,320,757, No. 2,588,765, No. 2,738,891, No. 3,308,178, No. 3,302,522, No. 30,803,030, No.3020887, No. 3,212,178, No. 3,222,597, No. 3,489,567, No. 3,516,883, No. 3,658,573 3679411, 3870521, JP-A-49-5017, 51-141623, 54-159221, 56-81841, and Research Disclosure Jar has been described in (Research Disclosure) No. 13969.
[0075]
The amount of the slip agent or the release agent used is 5 to 500 mg / m.², Preferably 10 to 200 mg / m²It is appropriate that A preferable amount of the slip agent or the release agent in the case of so-called oil-less fixing that does not use the oil for the purpose of preventing the offset to the fixing member in the fixing unit is, for example, 30 to 3000 mg / m.², Preferably 100-1500 mg / m²It is.
Since the wax-based slip agent or the release agent is difficult to dissolve in an organic solvent, it is preferable to prepare an aqueous dispersion, prepare a dispersion with a thermoplastic resin solution, and apply it. In this case, the wax-based slip agent or release agent is present in the form of fine particles in the thermoplastic resin. In this case, the amount of slip agent used is 5 to 10,000 mg / m.², Preferably 50 to 5000 mg / m²It is.
Examples of the slipping agent or release agent include silicone compounds, fluorine compounds, and waxes.
[0076]
As the slipping agent or mold release agent, compounds described in “Summary of properties and applications of revised wax” by Kosho Shobo or the Silicone Handbook published by Nikkan Kogyo Shimbun, Inc. can be generally used. JP-B-59-38581, JP-B-4-32380, JP-B-2838498, JP-B-2 29558, JP-A Nos. 50-117433, 52-52640, 57-148755, and 61-62056. No. 61-62057, No. 61-118760, JP-A-2-42451, No. 3-41465, No. 4-212175, No. 4-214570, No. 4-263267, No. 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, silicone compounds, fluorine compounds, waxes, etc. used in the toners are preferably used. Is done. Further, a plurality of these compounds can be used in combination.
[0077]
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, F-3800 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 Dowconi SF8417, SM8709 made by Ning Silicone, TSF4700, TSF4701, TSF4702, TSF4702, 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 modified 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 (KF made by Shin-Etsu Chemical) -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 oils (Toray Dow Corning Silicone SF8416, Toshiba Silicone TSF410, TSF411, TSF4420, TSF4421, TSF4422, TSF4450, XF42-334, XF42-A3160, XF42-A3161, etc.), fluorine-modified silicone Oil (commercially available FS1265 made by Toray Dow Corning Silicone, Toshiba Silicone 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) Dairy Seika's Dialomer SP203V, SP712, SP2105, SP3023; Nippon Oil & Fats Modiper FS700, FS710, FS720, FS730, FS770; Toa Gosei Chemical Co., Ltd. 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, TE2175, 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, TP 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, and the like.
[0078]
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 resins (Nippon Yushi Modiper F200, F220, F600, F2020, F3035; Dainichi Seika's 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.).
[0079]
Examples of the wax include petroleum wax, synthetic hydrocarbon, modified wax, hydrogenated wax, and natural wax.
[0080]
As the petroleum wax, paraffin wax (Nippon Seiki paraffin wax 155, 150, 140, 135, 130, 125, 120, 115, HNP-3, HNP-5, HNP-9, HNP-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-2151, 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, 130 ° paraffin made by Nisseki Mitsubishi Oil 135 ° paraffin, 135 ° H, 140 ° paraffin, 140 ° N, 145 ° paraffin, paraffin wax M, etc., microcrystalline wax (Nippon Seiki Hi-Mic-2095, Hi-Mic-3090, Hi as commercial products) -Mic-1080, Hi-Mic-1070, Hi-Mic-2065, Hi-Mic-1045, Hi-Mic-2045, EMUSTAR-0001, EMUSTAR-042X, Chukyo Yushi Cellosol 967, M, manufactured by Mitsubishi Oil Corporation 155 microwax, 180 microwax, etc.), Petrolatum (commercially available products from 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) and the like.
[0081]
Examples of the synthetic hydrocarbon include polyethylene wax (as commercially available products Polylon A, 393, H-481, manufactured by Chukyo Yushi Co., Ltd., Sanyo Kasei Sun Wax E-310, E-330, E-250P, LEL-250, LEL-800, LEL-400P, etc.), polypropylene wax (Sanyo Kasei Biscol 330-P, 550-P, 660-P), Fischer-Tropsch wax (Nippon Seiki FT100, FT-0070, etc.) Amide compounds or acid imide compounds (specifically, stearamide, phthalic anhydride imide, etc., commercially available products such as Chukyo Yushi Cellosol 920, B-495, Hymicron G-270, G-110, Hydrin D-757, etc. ) And the like.
[0082]
Examples of the modified wax include amine-modified polypropylene (QN-7700 manufactured by Sanyo Chemical Co., Ltd. as a commercial product), acrylic acid-modified, fluorine-modified, olefin-modified wax, and urethane-type wax (NPS-6010 and HAD-5090 manufactured by Nippon Seiki as commercial products). Etc.), alcohol type waxes (NPS-9210, NPS-9215, OX-1949, XO-020T, etc., manufactured by Nippon Seiki) and the like.
[0083]
Examples of the hydrogenated wax include hydrogenated castor oil (such as a castor wax manufactured by Ito Oil Co., Ltd.), castor oil derivatives (dehydrated castor oil DCO, DCO Z-1, DCO Z-3, castor oil fatty acid manufactured by Ito Oil Co., Ltd. as commercial products). CO-FA, 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 MINERASOLRC-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-70 , # 11, L-164, etc.), stearic acid (such as 12-hydroxystearic acid made by Ito Oil as a commercial product), lauric acid, myristic acid, palmitic acid, behenic acid, sebacic acid (made by Ito Oil as commercial products) Sebacic acid, etc.), undecylenic acid (such as undecylenic acid made by Ito Oil as a commercial product), heptylic acid (such as heptyl acid from Ito Oil as a commercial product), maleic acid, highly maleated oil (made by Ito Oil as a commercial product) HIMALIN DC-15, LN-10, 00-15, DF-20, SF-20, etc.), blown oil (commercially available from Celonol # 10, # 30, # 60, R-40, S-40 manufactured by Ito Oil) 7), and synthetic waxes such as cyclopentadiened oil (CP oil, CP oil-S, etc. made by Ito Oil as commercial products). That.
[0084]
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 toner image-receiving layer.
[0085]
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.
[0086]
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, 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.
[0087]
Content (g / m) of the natural wax in the toner 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.
[0088]
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.
[0089]
As a slipping agent or a release agent optionally added to the toner 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.
The slip agent or the release agent used in the present invention is, for example, 0.1 to 10% by mass, preferably 0.3 to 8.0% by mass, particularly preferably, based on the mass of the toner image-receiving layer. It is suitable to set it as 0.5-5.0 mass%.
The amount of the slip agent or release agent used is 5 to 500 mg / m.²It is preferable that More preferably 10 to 200 mg / m²It is. In the case of so-called oil-less fixing that does not use oil for the purpose of preventing offset to the fixing member in the fixing unit, the amount of slip agent is, for example, 30 to 3000 mg / m.², Preferably 100-1500 mg / m²It is appropriate that
[0090]
-Matting agent-
The matting agent is used, for example, for preventing adhesion between image receiving sheets and preventing paper jam in an electrophotographic apparatus. 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.
[0091]
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.
[0092]
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.
[0093]
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. 2376005, No. 233911, No. 2701245, No. 2992101, No. 3079257, 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 diameter 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
[0094]
-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 the compounds described in “The Chemistry of Synthetic Dies” edited by Veen Rataraman, Vol. 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.
[0095]
As the white pigment, an inorganic pigment (for example, titanium oxide, calcium carbonate, etc.) described in the section of filler described later can be used. Examples of the colored pigment 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.
[0096]
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).
[0097]
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.
[0098]
Further, a colored coupler used in silver salt photography can also be preferably used.
[0099]
Content of the colorant in the toner 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 toner image-receiving layer is increased, while the colorant content is 8 g / m.²Exceeding may cause poor handling such as cracking and adhesion resistance.
[0100]
-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 Agent Basics and Applications" (Taiseisha), "Filler Handbook" (Taiseisha) 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, lead white, 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. If the particle size is large, the surface of the toner image-receiving layer tends to be roughened.
[0101]
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. The average particle diameter of silica is preferably 200 to 5000 nm.
The silica is preferably porous. The average pore diameter of the porous silica is preferably 4 to 120 nm, and more preferably 4 to 90 nm. Moreover, the average pore volume per mass of the porous silica is preferably, for example, 0.5 to 3 ml / g.
[0102]
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.
[0103]
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.
[0104]
-Crosslinking agent-
The cross-linking agent can be blended in order to adjust the storage stability, thermoplasticity, etc. of the toner image-receiving layer. 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.
[0105]
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., and "Handbook Rubber / Plastic Compounding Chemicals" (Rubber Digest) The publicly known thing mentioned by the company edition) etc. can be used.
[0106]
-Charge control agent-
The toner image-receiving layer of the present invention preferably contains a charge adjusting agent in order to adjust toner transfer, adhesion, etc., and to prevent charge adhesion of the toner 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.
[0107]
When the toner has a negative charge, for example, a cation or nonion is preferable as the charge adjusting agent to be blended in the toner 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.
[0108]
-Other additives-
The material that can be used in the toner 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 toner image-receiving layer itself. Additives for this purpose include various known antioxidants, anti-aging agents, anti-aging agents, anti-ozone deterioration agents, ultraviolet absorbers, metal complexes, light stabilizers, antiseptics, fungicides, etc. Can be mentioned.
[0109]
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.
[0110]
Examples of the antiaging agent include those described in “Handbook Rubber / Plastic Compounding Chemicals Revised 2nd Edition” (1993, Rubber Digest Co.) p76-121.
[0111]
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).
[0112]
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.
Further, ultraviolet absorbers and light stabilizers described in "Handbook Rubber / Plastic Compounding Chemicals Revised 2nd Edition" (1993, Rubber Digest Co., Ltd.) p122 to 137 are also preferably used.
[0113]
As described above, known photographic additives can be added to the material that can be used in the toner image-receiving layer of the present invention. As photographic additives, for example, Research Disclosure Magazine (hereinafter abbreviated as RD) No. 17643 (December 1978), No. 1 18716 (November 1979) and 307105 (November 1989), and the corresponding parts are summarized below.

[0114]
The toner image-receiving layer of the present invention is provided by applying an aqueous dispersion of core / shell type latex particles used for an electrophotographic toner image-receiving layer on the support with a wire coater or the like and drying.
[0115]
The toner image-receiving layer of the present invention has a coating weight after drying of, for example, 1 to 20 g / m.², Preferably 4-15 g / m²It is applied to become.
The thickness of the toner image receiving layer is not particularly limited, but is preferably 1 to 30 μm, and more preferably 2 to 20 μm.
[0116]
[Physical properties of toner image-receiving layer]
The toner image receiving layer preferably has high whiteness. The whiteness is preferably 85% or more as measured by the method defined in JISP 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 range of 400 nm to 700 nm, and the difference between the maximum spectral reflectance and the minimum spectral reflectance in the same wavelength range 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.
[0117]
The toner 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.
In addition, the said glossiness can be measured based on JISZ8741.
[0118]
The toner 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.
[0119]
The toner 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 toner image-receiving layer has a Tg (glass transition temperature) of 30 ° C. or higher and a toner Tg + 20 ° C. or lower.
(2) T1 / 2 (1/2 method softening point) of the toner 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 while applying a predetermined extrusion load under a specific condition using a specific apparatus. 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 toner image-receiving layer is 40 to 200 ° C., preferably, Tfb of the toner image-receiving layer is Tfb + 50 ° C. or less of the toner.
(4) The viscosity of the toner 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 toner image-receiving layer is 1 × 10²~ 1x10⁵Pa, loss elastic modulus (G ″) is 1 × 10²~ 1x10⁵Pa.
(6) The loss tangent (G ″ / G ′), which is the ratio between the loss elastic modulus (G ″) at the fixing temperature of the toner 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 toner 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 toner image-receiving layer is 50 degrees or less, particularly 40 degrees or less.
The toner image-receiving layer preferably satisfies the physical properties disclosed in Japanese Patent No. 2788358, Japanese Patent Application Laid-Open Nos. 7-248637, 8-305067, and 10-239889.
[0120]
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.
[0121]
As the toner image-receiving layer, 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 toner image-receiving layer is not sufficient, and the density of the obtained 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.
[0122]
The surface electrical resistance of the surface opposite to the toner 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.
[0123]
[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 tint 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.
[0124]
-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 toner 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 toner image receiving layer. However, thermodynamic characteristics, electrostatic characteristics, and the like do not need to be the same as those of the toner image-receiving layer, and can be optimized.
[0125]
The surface protective layer may contain the various additives described above that can be used for the toner 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.
[0126]
-Back layer-
In the electrophotographic image-receiving sheet of the present invention, the back layer is on the opposite side of the toner image-receiving layer from the support for the purpose of imparting backside output suitability, improving backside output image quality, improving curl balance, improving device passability, etc. Is preferably 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 may have the same structure as that of the toner image receiving layer for improving 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.
[0127]
-Adhesion improvement layer, etc.-
The adhesion improving layer is preferably formed for the purpose of improving the adhesion between the support and the toner 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 toner image-receiving layer in order to improve toner acceptability.
[0128]
-Intermediate layer-
The intermediate layer is 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 toner image receiving layer, and between the toner image receiving layer and the storage stability improving layer. Can do. Of course, in the case of an electrophotographic image-receiving sheet comprising a support, a toner image-receiving layer, and an intermediate layer, the intermediate layer can be present, for example, between the support and the toner image-receiving layer.
[0129]
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.
[0130]
<Toner>
  Electrophotographic image-receiving sheet of the present inventionImage forming methodCauses the toner image-receiving layer to receive toner during printing or copying.
  The toner contains at least a binder resin and a colorant, and if necessary, a release agent and other components.
[0131]
-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 preferable to use resins of the same system as those used for the toner image receiving layer of the present invention.
[0132]
-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.
[0133]
-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.
[0134]
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
[0135]
Specific examples of the raw material compound include monoisocyanate compounds such as dodecyl isocyanate, phenyl isocyanate and derivatives thereof, naphthyl isocyanate, hexyl isocyanate, benzyl isocyanate, butyl isocyanate, and allyl isocyanate. It is done.
Examples of diisocyanate compounds 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.
[0136]
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. Also, when used in the emulsion polymerization aggregation melting toner described above, it is dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid or a polymer base, and heated to a melting point or higher to produce a homogenizer or pressure discharge. A fine dispersion is obtained by applying strong shearing with a mold disperser to prepare a release agent particle dispersion of 1 μm or less, which can be used together with a resin particle dispersion, a colorant dispersion and the like.
[0137]
-Toner and other components-
Further, the toner of the present invention 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.
[0138]
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.
[0139]
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.
[0140]
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.
[0141]
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, fatty acid or its derivative (s), powders, such as these metal salts, resin powders, such as 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.
[0142]
The method for producing the toner is not particularly limited, and (i) a step of forming an aggregated particle 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 the adhered particles; and (iii) heating and fusing the adhered particles to form toner particles. A toner obtained by a method for producing a toner including the steps is preferable.
[0143]
-Toner physical properties-
The volume average particle diameter of the toner of the present invention is preferably from 0.5 μm to 10 μm. If the volume average particle diameter 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 diameter of the toner is too large, the image quality and resolution due to graininess and transferability may be adversely affected.
Further, the toner of the present invention preferably satisfies the volume average particle size range of the toner 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.
In addition, 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 × L²) / (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. Also, it is difficult to cause omission and blur due to transfer, and handling properties are hardly adversely affected even if the average particle size is not small. Become.
[0144]
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.
[0145]
<Image forming method>
In the image forming method of the present invention, as a first aspect, after a toner image is formed on the electrophotographic image receiving sheet, the image forming surface of the electrophotographic image receiving sheet is heated by a fixing belt and a fixing roller. And after pressurizing and cooling, it peels from the fixing belt.
In the image forming method of the present invention, as a second aspect, after the toner image is formed on the electrophotographic image receiving sheet and fixed by a heat roller, the image forming of the electrophotographic image receiving sheet is further performed. The surface is heated and pressed by a fixing belt and a fixing roller, cooled, and then peeled off from the fixing belt.
[0146]
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 transferred to an electrophotographic image receiving sheet, or a primary transfer to an intermediate transfer belt or the like. Then, there is an intermediate transfer belt system for transferring to an electrophotographic image receiving sheet. From the viewpoint of environmental stability and high image quality, an intermediate transfer belt system is preferably used.
[0147]
In the electrophotographic image receiving sheet of the present invention, the toner transferred onto the electrophotographic image receiving sheet is fixed on 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, for example, conveys at least a heating and pressurizing unit capable of melting and pressurizing toner and an electrophotographic image receiving sheet on which the toner is adhered in contact with the toner image receiving layer. An electrophotographic apparatus having a belt-type toner fixing unit having a fixing belt that can be cooled and optionally a cooling unit that can cool a heated electrophotographic image-receiving sheet attached to the fixing belt. By using an electrophotographic image-receiving sheet having a toner image-receiving layer in an electrophotographic apparatus having such a fixing belt, the toner adhering to the toner image-receiving layer is finely fixed without spreading on the electrophotographic image-receiving sheet. At the same time, since the molten toner is cooled and solidified in close contact with the fixing belt, the toner is completely received in the toner image receiving layer and is received by the toner image receiving layer. Therefore, it is possible to obtain a glossy and smooth toner image with no image level difference.
[0148]
The electrophotographic image-receiving sheet formed according to 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.
[0149]
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. 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.
[0150]
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.
[0151]
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 polymer in the toner binder resin and / or the toner 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 toner 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.
[0152]
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 sheet (1) to which the toner (12) is attached is conveyed to a point A by a conveying facility (not shown), passes between the heating roller (14) and the pressure roller (15), and receives an image for electrophotography. The toner image-receiving layer or the toner (12) of the sheet (1) is heated and pressed at a temperature (fixing temperature) and pressure at which it is sufficiently softened.
[0153]
Here, the fixing temperature means the temperature of the surface of the toner image-receiving layer measured at the position of the heating roller (14), the pressure roller (15) and the nip portion at point A, and is preferably 80 to 190 ° C., for example. Is 100-170 ° C. The pressure means the pressure on the surface of the toner image-receiving layer measured at the heating roller (14), the pressure roller (15), and the nip, and is, for example, 1 to 10 kg / cm.²More preferably, 2-7 kg / cm²It is. While being heated and pressurized in this way, the electrophotographic image-receiving sheet (1) was later separated from the toner image-receiving layer while being conveyed to the cooling device (16) by the fixing belt (13). The mold (not shown) is sufficiently heated and melted, and moves to the surface of the toner image receiving layer. The released release agent forms a release agent layer (film) on the surface of the toner image-receiving layer. Thereafter, the electrophotographic image-receiving sheet (1) is conveyed to the cooling device (16) by the fixing belt (13) and is, for example, below the softening point of the polymer of the toner image-receiving layer and / or the binder resin used for the toner. It is cooled to a glass transition point + 10 ° C or lower, 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 toner image receiving layer is cooled and solidified, and a release agent layer is formed by the change of the release agent in the toner 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).
[0154]
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.
[0155]
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.
[0156]
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.
[0157]
[Chemical 1]

[0158]
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.
[0159]
Examples of the component (A) include those represented by the following formula (2).
[0160]
[Chemical formula 2]

[0161]
In the component (B), examples of the organopolysiloxane having an ≡SiH group include organohydrogenpolysiloxanes having at least two hydrogen atoms bonded to silicon atoms in the molecule.
[0162]
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.
[0163]
As such organohydrogenpolysiloxane, various organohydrogenpolysiloxanes used in addition-curable silicone rubber compositions can be used.
[0164]
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.
[0165]
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).
[0166]
[Chemical Formula 3]

[0167]
As the filler of the 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.
[0168]
As the catalyst of the 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, alumina, silica, carbon, etc. Examples are those supported on the above-mentioned carriers, 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 being dissolved in a solvent such as an alcohol, ether, or hydrocarbon.
[0169]
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.
[0170]
The fixing belt of the present invention is obtained by coating the surface of a heat resistant resin or metal belt body with the fluorocarbon siloxane rubber composition, followed by heat curing. It can be diluted with a solvent such as hexafluoride or benzotrifluoride to form a coating solution, which can be applied by a general coating method such as spray coating, dip coating or knife coating. Moreover, the temperature and time of heat curing can be selected suitably, and are selected according to the kind of belt main body, a manufacturing method, etc. in the range of normal temperature 100-500 degreeC and 5 second-5 hours.
[0171]
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.
[0172]
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 an electrophotographic method using a fixing belt. Any ordinary electrophotographic method can be applied.
For example, a color image can be preferably formed on the electrophotographic image-receiving sheet of the present invention. 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.
[0173]
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.
[0174]
According to the image forming method of the present invention, even when an oil-less machine without fixing oil is used, the releasability of the electrophotographic image receiving sheet and toner, or the offset of the image receiving sheet and toner component can be prevented, and stable paper feeding is possible. In addition, it is possible to realize a good image having an unprecedented glossiness and rich in photographic feeling.
[0175]
【Example】
Examples of the present invention will be described below, but the present invention is not limited to these examples.
In the following examples and comparative examples, “%” and “part” represent “% by mass” and “part by mass”, respectively.
[0176]
Example 1
-Preparation of aqueous dispersion of core / shell type latex particles-
An aqueous dispersion of core / shell type latex particles was prepared by a seed method. As a seed polymer, a copolymer (number average molecular weight (Mn) of 2-ethylhexyl acrylate (EHA) and methyl methacrylate (MMA) was copolymerized at a mass ratio of 95: 5. ) = 11000) (average particle size 0.06 μm) to a methyl ratio (MMA), butyl acrylate (BA) and methacrylic acid (MAA) in a mass ratio of 67:23:10 Into the mixture, ammonium persulfate was added as a polymerization initiator, polymerization was started at 60 ° C., and an aqueous dispersion (solid content) of core / shell latex particles having an average particle size of 0.08 μm at Mn = 6700. Content 30%).
[0177]
(Examples 2-5 and Comparative Examples 1-11)
In the same manner as in Example 1, aqueous dispersions (solid content 30%) of core / shell type latex particles of Examples 2 to 5 and Comparative Examples 1 to 11 were obtained. The properties of the obtained core / shell type latex particles are shown in Tables 1 and 2 below. In addition, the viscosity and surface tension values of the obtained aqueous dispersion were also described.
[0178]
(Comparative Example 12)
This Comparative Example 12 shows an example in which an aqueous dispersion of core / shell type latex particles was prepared using an emulsifier.
As the first step, 2-ethylhexyl acrylate (EHA) 9%, methyl methacrylate (MMA) 5%, sodium dodecylbenzenesulfonate 2% as an anionic surfactant, and ammonium persulfate as an initiator are polymerized. As a second step, 67% of methyl methacrylate (MMA) and 23% of butyl acrylate (BA) are added, and the polymerization is further advanced. The core Mn (c) is 11000, the shell Mn (s ) 6700 core / shell latex aqueous dispersion (solid content 30%).
The properties of the obtained core / shell type latex particles are shown in Tables 1 and 2 below. In addition, the viscosity and surface tension values of the obtained aqueous dispersion were also described.
[0179]
-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.
Type of additive Amount (%)
Cationic starch 1.2
Alkyl ketene dimer (AKD) 0.5
Anionic polyacrylamide 0.3
Epoxidized fatty acid amide (EFA) 0.2
Polyamide polyamine epichlorohydrin 0.3
Note) AKD means an alkyl ketene dimer (the alkyl part is derived from a fatty acid mainly composed of behenic acid), and EFA is an epoxidized fatty acid amide (the fatty acid part is derived from a fatty acid mainly composed of behenic acid). ).
[0180]
The obtained pulp paper stock was basis weight 150 g / m by a long net paper machine.²A base paper was prepared. In addition, PVA 1.0 g / m by a size press machine in the middle of the drying zone of the long paper machine.², CaCl₂  0.8g / m²Attached.
At the end of the papermaking process, using a soft calendar, the density is 1.01 g / cm³Adjusted. In the obtained base paper, the metal roll was passed through on the side where the toner image-receiving layer was provided, and the surface temperature of the metal roll was 140 ° C.
[0181]
-Preparation for toner image-receiving layer-
The aqueous dispersions of the core / shell type latex particles of Examples 1 to 5 and Comparative Examples 1 to 12 were applied to the surface of the base paper support (the side on which the toner image receiving layer was formed) using a bar coater. The coating amount was 12 g of dry mass.
[0182]
-Preparation of coating solution for back layer-
The following components were mixed and stirred to prepare a coating solution for the back layer.
Acrylic resin water dispersion
(Solid content 30%, high loss XBH-997L, manufactured by Seiko Chemical) 100.0 g
Matting agent
(Tecpomer MBX-12, manufactured by Sekisui Plastics) 5.0 g
Release agent (Hydrin D337, manufactured by Chukyo Yushi) 10.0 g
Thickener (CMC) 2.0g
Anionic surfactant (AOT) 0.5g
Ion exchange water 80ml
[0183]
The viscosity of the coating solution for the back layer was 35 mPa · s, and the surface tension was 33 mN / m.
[0184]
-Coating of back layer-
On the back surface of the support, the coating liquid for the back layer was applied with a bar coater in the same manner as for the toner image receiving layer. The coating amount is 9 g / m in dry mass.²Met. The toner image-receiving layer and the back layer were dried online with hot air after coating. In 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 kN / m (15 kgf / cm) using a gloss calendar with the metal roller kept at 40 ° C.
[0185]
<Evaluation of physical properties of electrophotographic image-receiving sheet>
An image is formed on the electrophotographic image-receiving sheet produced according to each of the above examples and comparative examples by using the fixing belt type electrophotographic apparatus shown in FIG. 1, and has an adhesion resistance, a crack resistance, a glossiness and an offset property. It was measured. The results are shown in Table 3.
[0186]
As images for printing, white solid, gray (R = G = B = 50% of the image), black (100%), and female portrait images were used. As an electrophotographic apparatus, a color laser printer (C-2220) manufactured by Fuji Xerox was used except that an apparatus having the following fixing belt was used.
As a fixing belt base material, DY39-115 which is a primer for silicone rubber made by Toray Dow Corning Silicone Co., Ltd. is applied on a base layer made of polyimide, air-dried for 30 minutes, and then DY35-796AB 100 which is a silicone rubber precursor. A coating film was formed by dip coating a coating solution adjusted 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
[0187]
In this fixing belt system, the conveyance speed of the fixing belt (13) is 30 mm / second, and the nip pressure between the heating roller (14) and the pressure roller (15) is 0.2 MPa (2 kgf / cm).²The set temperature of the heating roller (14) is 155 ° C., which corresponds to the fixing temperature. The set temperature of the pressure roller (15) was 130 ° C. The electrophotographic image-receiving sheet was cooled to 60 ° C. or lower when it was peeled from the fixing belt (13).
Using this apparatus, the portrait image and a white solid, gray, and black 5 cm square pattern were transferred to an electrophotographic image receiving sheet.
[0188]
<< Adhesion resistance >>
The obtained electrophotographic image-receiving sheet was adjusted to 40 ° C. and 80% RH for 24 hours, and then the toner image-receiving surfaces were opposed to each other so as to face each other, and 3.5 cm □ (Acm □ means Acm each of length × width) .) After applying a weight of × 500 g and leaving it in the same environment for 7 days, the state when the electrophotographic image-receiving sheet was pulled off was observed and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
1: No peeling sound and adhesion mark.
2: There is a slight peeling sound or adhesion mark.
3: The adhesion mark is less than 1/4.
4: Adhesion trace is 1/4 or more and less than 1/2.
5: Adhesion trace is 1/2 or more.
[0189]
<< crackability >>
A color laser printer C-2220 manufactured by Fuji Xerox Co., Ltd. is used (however, the fixing unit is changed to the above-described belt fixing method), and a uniform 10 cm square image is printed with the maximum density of black. Leave at 10 ° C. and 15% RH for 1 day. Prepare round bars with diameters of 1, 2, 3, 4 and 5 cm, wrap them around the small diameter bar in order from the large diameter bar so that the image surface is on the outside, observe the occurrence of cracks, and generate cracks Record the diameter.
[0190]
<< Glossiness (%) >>
Using a color laser printer C-2220 manufactured by Fuji Xerox Co., Ltd. (however, the fixing unit was changed to the belt fixing method described above), and the density was changed in six levels (0, 20, 40, 60cm, 80% and 100%). The six-stage part is measured by JIS Z 8741, a digital variable angle glossiness meter (manufactured by Suga Test Instruments Co., Ltd., UGV-5D), 45 degree measurement, and the minimum value is recorded.
[0191]
<< Offset property >>
Using a color laser printer C-2220 (oilless fixing method) manufactured by Fuji Xerox Co., Ltd., passing normally through the fixing part in an environment of 30 ° C. and 80% RH, The state is evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
○: None
Δ: Slightly generated
×: Many occurrences
[0192]
[Table 1]

Note 1) x10³
Note 2) Shell or core ratio (mass) in core / shell type latex particles
[0193]
[Table 2]

[0194]
[Table 3]

[0195]
In addition, when printing was performed with a commercially available color laser printer, specifically, a full color laser printer (DCC-400CP / 320CP, DCC-500CP) manufactured by Fuji Xerox, all the samples could be passed, and the same results as in Table 3 were obtained. was gotten.
[0196]
【The invention's effect】
As described above, according to the present invention, the core / shell latex particles in the aqueous dispersion applied to the support are synthesized without using an emulsifier, and (1) the number average molecular weight of the core [Mn (c)] and the number average molecular weight [Mn (s)] of the shell satisfy Mn (c)> Mn (s), and (2) the number average molecular weight [Mn (c)] of the core is (3) The number average molecular weight [Mn (s)] of the shell is 4000 to 30000, and (4) the mass ratio of the core to the shell is 10:90 to 90:10. (5) When the average particle size of the latex particles is 0.2 μm or less, the resulting aqueous dispersion is simply applied to simultaneously improve offset resistance and crack prevention. Manufactured electrophotographic image-receiving sheet It rukoto be seen.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an example of a fixing belt type electrophotographic apparatus of the present invention.
[Explanation of symbols]
1 Electrophotographic image-receiving sheet
12 Toner
13 Fixing belt
14 Heating roller
15 Pressure roller
16 Cooling device
17 Tension roller

Claims (22)

An aqueous dispersion of core / shell type latex particles used for an electrophotographic toner image-receiving layer,
The core / shell type latex particles are synthesized without using an emulsifier,
An aqueous dispersion of core / shell type latex particles used for an electrophotographic toner image-receiving layer, wherein the core / shell type latex particles satisfy the following characteristics (1) to (5).
(1) The number average molecular weight [Mn (c)] of the core and the number average molecular weight [(Mn (s)] of the shell have the following relationship: Mn (c)> Mn (s)
(2) The number average molecular weight [Mn (c)] of the core is 30000-500000 (3) The number average molecular weight [Mn (s)] of the shell is 4000-30000 (4) The mass ratio of the core to the shell is 10:90 to 90:10. (5) The average diameter of the latex particles is 0.2 μm or less.   2. The aqueous dispersion according to claim 1, wherein the shell has a glass transition temperature [Tg (s)] of 30 to 100 ° C. 3. When the glass transition temperature [Tg (c)] of the core is calculated by the following Dimarzio equation, the glass transition temperature [Tg (t)] of the latex particles composed of the core / shell is 10 ° C. or less. The aqueous dispersion according to claim 1 or 2.
1 / Tg (t) = w (c) / Tg (c) + w (s) / Tg (s)
(Where Tg (t) is the Tg at the absolute temperature of the latex particles, Tg (c) is the Tg at the absolute temperature of the core, and Tg (s) is the Tg at the absolute temperature of the shell. W (c) is the mass ratio of the core in the latex particles, and w (s) is the mass ratio of the shells in the latex particles.)   4. An electrophotographic image-receiving sheet having a support and a toner image-receiving layer provided on at least one surface of the support, wherein the toner image-receiving layer is a core / shell type according to claim 1. An electrophotographic image-receiving sheet, which is formed from an aqueous dispersion of latex particles.   The electrophotographic image-receiving sheet according to claim 4, wherein the toner image-receiving layer contains a natural wax, and the natural wax is at least one of a plant wax and a mineral wax.   The electrophotographic image-receiving sheet according to claim 5, wherein the plant wax is carnauba wax having a melting point of 70 to 95 ° C.   The electrophotographic image-receiving sheet according to claim 5, wherein the mineral wax is a montan wax having a melting point of 70 to 95 ° C.   The electrophotographic image-receiving sheet according to any one of claims 4 to 7, wherein the support is selected from a base paper, a synthetic paper, a synthetic resin sheet, a coated paper, and a laminated paper. A method for producing an electrophotographic image-receiving sheet according to any one of claims 4 to 8, wherein the aqueous dispersion according to any one of claims 1 to 3 is applied onto the support. A method for producing an electrophotographic image-receiving sheet. The method for producing an electrophotographic image-receiving sheet according to claim 9, wherein the viscosity of the aqueous dispersion is 10 mPa · s or more. The method for producing an electrophotographic image-receiving sheet according to claim 9 or 10, wherein a surface tension of the aqueous dispersion is 50 mN / m or less. The manufacturing method of the image receiving sheet for electrophotography in any one of Claim 9 to 11 which carries out a calendar process after coating the said aqueous dispersion. The image forming method for forming an image on the electrophotographic image-receiving sheet according to any one of claims 4 to 8, wherein the toner received in the toner image-receiving layer contains at least a binder resin and a colorant, An image forming method wherein the toner has a volume average particle size of 0.5 μm or more and 10 μm or less and a volume average particle size distribution index (GSDv) of 1.3 or less. 14. The image forming method according to claim 13, wherein the toner has a ratio (GSDv / GSDn) of a volume average particle size distribution index (GSDv) to a number average particle size distribution index (GSDn) of at least 0.95. The toner received in the toner image-receiving layer contains at least a binder resin and a colorant, the volume average particle diameter of the toner is 0.5 μm or more and 10 μm or less, and the average value of the shape factor represented by the following formula is The image forming method according to claim 13 or 14, which is 1.00 to 1.50.
Shape factor = (π × L ² ) / (4 × S)
(However, L represents the maximum length of toner particles, and S represents the projected area of toner particles.) The toner to be received in the toner image-receiving layer is at least (i) 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 the adhered particles; and (iii) a step of heating and fusing the attached particles to form toner particles. The image forming method according to claim 13, wherein the image forming method is obtained by a toner manufacturing method including: A picture A method of forming a oilless method using a electrophotographic image-receiving sheet according to any one of claims 4 to 8, wherein the electrophotographic image-receiving sheet, after forming a toner image, said electrophotographic An image forming method, wherein the image forming surface of the image receiving sheet is heated and pressed by a fixing belt and a fixing roller, cooled, and then peeled off from the fixing belt. An oil-less method for forming an image using the electrophotographic image-receiving sheet according to any one of claims 4 to 8 , wherein a toner image is formed on the electrophotographic image-receiving sheet and then heated by a heat roller. After fixing, the image forming surface of the electrophotographic image-receiving sheet is further heated and pressed by a fixing belt and a fixing roller, cooled, and then peeled off from the fixing belt.   The image formation according to claim 17 or 18, wherein the formed toner image is peeled off from the belt-like fixing member after being cooled to a state below the softening point of a binder resin used for the toner or a glass transition point + 10 ° C or less. Method.   The image forming method according to claim 17, wherein a layer made of a fluorocarbon siloxane rubber having a uniform thickness is provided on the surface of the fixing belt.   20. The image according to claim 17, further comprising a silicone rubber layer having a uniform thickness on the surface of the fixing belt, and a fluorocarbon siloxane rubber layer provided on the surface of the silicone rubber layer. Forming method.   The image forming method according to claim 20 or 21, wherein the fluorocarbon siloxane rubber has a perfluoroalkyl ether group and / or a perfluoroalkyl group in a main chain.

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