JP3877212B2 - Full-color image forming device - Google Patents

Description

【化４】

次に、Ｃｐ_１とＣｐ_２が異なる場合について示す。
【化５】

【化６】

【化７】

【化８】

また、２７．２゜に最大回折ピークを有するチタニルフタロシアニンの中でも、更に９．４゜、９．６゜、２４．０゜に主要なピークを有し、かつ最も低角側の回折ピークとして７．３゜にピークを有し、７．３゜のピークと９．４゜のピークの間にピークを有さず、更に２６．３゜にピークを有さないチタニルフタロシアニン結晶は、特に高感度を示し、また感光体繰り返し使用における帯電性の低下も小さく、本発明の感光体の電荷発生物質として良好に使用できる。
【００６６】
電荷発生層３５は、必要に応じて結着樹脂とともに適当な溶剤中にボールミル、アトライター、サンドミル、超音波などを用いて分散し、これを導電性支持体上に塗布し、乾燥することにより形成される。
必要に応じて電荷発生層３５に用いられる結着樹脂としては、ポリアミド、ポリウレタン、エポキシ樹脂、ポリケトン、ポリカーボネート、シリコン樹脂、アクリル樹脂、ポリビニルブチラール、ポリビニルホルマール、ポリビニルケトン、ポリスチレン、ポリスルホン、ポリ−Ｎ−ビニルカルバゾール、ポリアクリルアミド、ポリビニルベンザール、ポリエステル、フェノキシ樹脂、塩化ビニル−酢酸ビニル共重合体、ポリ酢酸ビニル、ポリフェニレンオキシド、ポリアミド、ポリビニルピリジン、セルロース系樹脂、カゼイン、ポリビニルアルコール、ポリビニルピロリドン等が挙げられる。結着樹脂の量は、電荷発生物質１００重量部に対し０〜５００重量部、好ましくは１０〜３００重量部が適当である。
【００６７】
ここで用いられる溶剤としては、イソプロパノール、アセトン、メチルエチルケトン、シクロヘキサノン、テトラヒドロフラン、ジオキサン、エチルセルソルブ、酢酸エチル、酢酸メチル、ジクロロメタン、ジクロロエタン、モノクロロベンゼン、シクロヘキサン、トルエン、キシレン、リグロイン等が挙げられるが、特にケトン系溶媒、エステル系溶媒、エーテル系溶媒が良好に使用される。塗布液の塗工法としては、浸漬塗工法、スプレーコート、ビートコート、ノズルコート、スピナーコート、リングコート等の方法を用いることができる。
【００６８】
電荷発生層３５の膜厚は、０．０１〜５μｍ程度が適当であり、好ましくは０．１〜２μｍである。
電荷輸送層３７は、電荷輸送物質および結着樹脂を適当な溶剤に溶解ないし分散し、これを電荷発生層上に塗布、乾燥することにより形成できる。また、必要により可塑剤、レベリング剤、酸化防止剤等を添加することもできる。
【００６９】
電荷輸送物質には、正孔輸送物質と電子輸送物質とがある。電子輸送物質としては、例えばクロルアニル、ブロムアニル、テトラシアノエチレン、テトラシアノキノジメタン、２，４，７−トリニトロ−９−フルオレノン、２，４，５，７−テトラニトロ−９−フルオレノン、２，４，５，７−テトラニトロキサントン、２，４，８−トリニトロチオキサントン、２，６，８−トリニトロ−４Ｈ−インデノ〔１，２−ｂ〕チオフェン−４−オン、１，３，７−トリニトロジベンゾチオフェン−５，５−ジオキサイド、ベンゾキノン誘導体等の電子受容性物質が挙げられる。
【００７０】
正孔輸送物質としては、ポリ−Ｎ−ビニルカルバゾールおよびその誘導体、ポリ−γ−カルバゾリルエチルグルタメートおよびその誘導体、ピレン−ホルムアルデヒド縮合物およびその誘導体、ポリビニルピレン、ポリビニルフェナントレン、ポリシラン、オキサゾール誘導体、オキサジアゾール誘導体、イミダゾール誘導体、モノアリールアミン誘導体、ジアリールアミン誘導体、トリアリールアミン誘導体、スチルベン誘導体、α−フェニルスチルベン誘導体、ベンジジン誘導体、ジアリールメタン誘導体、トリアリールメタン誘導体、９−スチリルアントラセン誘導体、ピラゾリン誘導体、ジビニルベンゼン誘導体、ヒドラゾン誘導体、インデン誘導体、ブタジェン誘導体、ピレン誘導体等、ビススチルベン誘導体、エナミン誘導体等その他公知の材料が挙げられる。これらの電荷輸送物質は単独、または２種以上混合して用いられる。
【００７１】
結着樹脂としては、ポリスチレン、スチレン−アクリロニトリル共重合体、スチレン−ブタジエン共重合体、スチレン−無水マレイン酸共重合体、ポリエステル、ポリ塩化ビニル、塩化ビニル−酢酸ビニル共重合体、ポリ酢酸ビニル、ポリ塩化ビニリデン、ポリアレート、フェノキシ樹脂、ポリカーボネート、酢酸セルロース樹脂、エチルセルロース樹脂、ポリビニルブチラール、ポリビニルホルマール、ポリビニルトルエン、ポリ−Ｎ−ビニルカルバゾール、アクリル樹脂、シリコーン樹脂、エポキシ樹脂、メラミン樹脂、ウレタン樹脂、フェノール樹脂、アルキッド樹脂等の熱可塑性または熱硬化性樹脂が挙げられる。更に、後述する高分子電荷輸送物質も電荷輸送層の結着樹脂として好適に用いられる。高分子電荷輸送物質からなる電荷輸送層を用いた場合には、後述の表面保護層を積層する際に、高分子からなる故、電荷輸送物質の上層への溶け出しが少なく良好な結果を得る場合が多い。
【００７２】
電荷輸送物質の量は結着樹脂１００重量部に対し、２０〜３００重量部、好ましくは４０〜１５０重量部が適当である。また、電荷輸送層の膜厚は５〜１００μｍ程度とすることが好ましい。ここで用いられる溶剤としては、テトラヒドロフラン、ジオキサン、トルエン、ジクロロメタン、モノクロロベンゼン、ジクロロエタン、シクロヘキサノン、メチルエチルケトン、アセトンなどが用いられる。
【００７３】
本発明の感光体において電荷輸送層３７中に可塑剤やレベリング剤を添加してもよい。可塑剤としては、ジブチルフタレート、ジオクチルフタレートなど一般の樹脂の可塑剤として使用されているものがそのまま使用でき、その使用量は、結着樹脂に対して０〜３０重量％程度が適当である。レベリング剤としては、ジメチルシリコーンオイル、メチルフェニルシリコーンオイルなどのシリコーンオイル類や、側鎖にパーフルオロアルキル基を有するポリマーあるいは、オリゴマーが使用され、その使用量は結着樹脂に対して、０〜１重量％が適当である。
【００７４】
次に感光層が単層構成の場合について述べる。上述した電荷発生物質を結着樹脂中に分散した感光層が使用できる。単層感光層は、電荷発生物質および結着樹脂を適当な溶剤に溶解ないし分散し、これを塗布、乾燥することによって形成できる。更に、この感光層には上述した電荷輸送物質を添加した機能分離タイプとしても良く、良好に使用できる。また必要により、可塑剤やレベリング剤、酸化防止剤等を添加することもできる。
【００７５】
結着樹脂としては、先に電荷輸送層３７で挙げた結着樹脂をそのまま用いるほかに、電荷発生層３５で挙げた結着樹脂を混合して用いてもよい。もちろん、後述の高分子電荷輸送物質も結着樹脂および電荷輸送物質として、良好に使用できる。結着樹脂１００重量部に対する電荷発生物質の量は５〜４０重量部が好ましく、電荷輸送物質の量は０〜１９０重量部が好ましくさらに好ましくは５０〜１５０重量部である。単層感光層は、電荷発生物質、結着樹脂を必要ならば電荷輸送物質とともにテトラヒドロフラン、ジオキサン、ジクロロエタン、シクロヘキサン等の溶媒を用いて分散機等で分散した塗工液を、浸漬塗工法やスプレーコート、ビードコートなどで塗工して形成できる。単層感光層の膜厚は、５〜１００μｍ程度が適当である。
【００７６】
本発明の感光体においては、導電性支持体３１と感光層（電荷発生層）との間に下引き層を設けることができる。下引き層は一般には樹脂を主成分とするが、これらの樹脂はその上に感光層を溶剤で塗布することを考えると、一般の有機溶剤に対して耐溶剤性の高い樹脂であることが望ましい。このような樹脂としては、ポリビニルアルコール、カゼイン、ポリアクリル酸ナトリウム等の水溶性樹脂、共重合ナイロン、メトキシメチル化ナイロン等のアルコール可溶性樹脂、ポリウレタン、メラミン樹脂、フェノール樹脂、アルキッド−メラミン樹脂、エポキシ樹脂等、三次元網目構造を形成する硬化型樹脂等が挙げられる。また、下引き層にはモアレ防止、残留電位の低減等のために酸化チタン、シリカ、アルミナ、酸化ジルコニウム、酸化スズ、酸化インジウム等で例示できる金属酸化物の微粉末顔料を加えてもよい。
【００７７】
これらの下引き層は前述の感光層の如く適当な溶媒、塗工法を用いて形成することができる。更に本発明の下引き層として、シランカップリング剤、チタンカップリング剤、クロムカップリング剤等を使用することもできる。この他、本発明の下引き層には、Ａｌ₂Ｏ₃を陽極酸化にて設けたものや、ポリパラキシリレン（パリレン）等の有機物やＳｉＯ₂、ＳｎＯ₂、ＴｉＯ₂、ＩＴＯ、ＣｅＯ₂等の無機物を真空薄膜作成法にて設けたものも良好に使用できる。このほかにも公知のものを用いることができる。下引き層の膜厚は０〜５μｍが適当である。
また、本発明においては、耐環境性の改善のため、とりわけ、感度低下、残留電位の上昇を防止する目的で、各層に酸化防止剤、可塑剤、滑剤、紫外線吸収剤、低分子電荷輸送物質およびレベリング剤を添加することができる。これらの化合物の代表的な材料を以下に記す。
【００７８】
各層に添加できる酸化防止剤として、例えば下記のものが挙げられるがこれらに限定されるものではない。
（ａ）フェノール系化合物
２，６−ジ−ｔ−ブチル−ｐ−クレゾール、ブチル化ヒドロキシアニソール、２，６−ジ−ｔ−ブチル−４−エチルフェノール、ｎ−オクタデシル−３−（４−ヒドロキシ−３，５−ジ−ｔ−ブチルフェノール）、２，２−メチレン−ビス−（４−メチル−６−ｔ−ブチルフェノール）、２，２−メチレン−ビス−（４−エチル−６−ｔ−ブチルフェノール）、４，４−チオビス−（３−メチル−６−ｔ−ブチルフェノール）、４，４−ブチリデンビス−（３−メチル−６−ｔ−ブチルフェノール）、１，１，３−トリス−（２−メチル−４−ヒドロキシ−５−ｔ−ブチルフェニル）ブタン、１，３，５−トリメチル−２，４，６−トリス（３，５−ジ−ｔ−ブチル−４−ヒドロキシベンジル）ベンゼン、テトラキス−［メチレン−３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオネート］メタン、ビス［３，３−ビス（４−ヒドロキシ−３−ｔ−ブチルフェニル）ブチリックアッシド］グリコールエステル、トコフェロール類など。
（ｂ）パラフェニレンジアミン類
Ｎ−フェニル−Ｎ−イソプロピル−ｐ−フェニレンジアミン、Ｎ，Ｎ−ジ−ｓｅｃ−ブチル−ｐ−フェニレンジアミン、Ｎ−フェニル−Ｎ−ｓｅｃ−ブチル−ｐ−フェニレンジアミン、Ｎ，Ｎ−ジ−イソプロピル−ｐ−フェニレンジアミン、Ｎ，Ｎ−ジメチル−Ｎ，Ｎ−ジ−ｔ−ブチル−ｐ−フェニレンジアミン
など。
（ｃ）ハイドロキノン類
２，５−ジ−ｔ−オクチルハイドロキノン、２，６−ジドデシルハイドロキノン、２−ドデシルハイドロキノン、２−ドデシル−５−クロロハイドロキノン、２−ｔ−オクチル−５−メチルハイドロキノン、２−（２−オクタデセニル）−５−メチルハイドロキノンなど。
（ｄ）有機硫黄化合物類
ジラウリル−３，３−チオジプロピオネ−ト、ジステアリル−３，３−チオジプロピオネ−ト、ジテトラデシル−３，３−チオジプロピオネートなど。
（ｅ）有機燐化合物類
トリフェニルホスフィン、トリ（ノニルフェニル）ホスフィン、トリ（ジノニルフェニル）ホスフィン、トリクレジルホスフィン、トリ（２，４−ジブチルフェノキシ）ホスフィンなど。
【００７９】
各層に添加できる可塑剤として、例えば下記のものが挙げられるがこれらに限定されるものではない。
（ａ）リン酸エステル系可塑剤
リン酸トリフェニル、リン酸トリクレジル、リン酸トリオクチル、リン酸オクチルジフェニル、リン酸トリクロルエチル、リン酸クレジルジフェニル、リン酸トリブチル、リン酸トリ−２−エチルヘキシル、リン酸トリフェニルなど。
（ｂ）フタル酸エステル系可塑剤
フタル酸ジメチル、フタル酸ジエチル、フタル酸ジイソブチル、フタル酸ジブチル、フタル酸ジヘプチル、フタル酸ジ−２−エチルヘキシル、フタル酸ジイソオクチル、フタル酸ジ−ｎ−オクチル、フタル酸ジノニル、フタル酸ジイソノニル、フタル酸ジイソデシル、フタル酸ジウンデシル、フタル酸ジトリデシル、フタル酸ジシクロヘキシル、フタル酸ブチルベンジル、フタル酸ブチルラウリル、フタル酸メチルオレイル、フタル酸オクチルデシル、フマル酸ジブチル、フマル酸ジオクチルなど。
（ｃ）芳香族カルボン酸エステル系可塑剤
トリメリット酸トリオクチル、トリメリット酸トリ−ｎ−オクチル、オキシ安息香酸オクチルなど。
（ｄ）脂肪族二塩基酸エステル系可塑剤
アジピン酸ジブチル、アジピン酸ジ−ｎ−ヘキシル、アジピン酸ジ−２−エチルヘキシル、アジピン酸ジ−ｎ−オクチル、アジピン酸−ｎ−オクチル−ｎ−デシル、アジピン酸ジイソデシル、アジピン酸ジカプリル、アゼライン酸ジ−２−エチルヘキシル、セバシン酸ジメチル、セバシン酸ジエチル、セバシン酸ジブチル、セバシン酸ジ−ｎ−オクチル、セバシン酸ジ−２−エチルヘキシル、セバシン酸ジ−２−エトキシエチル、コハク酸ジオクチル、コハク酸ジイソデシル、テトラヒドロフタル酸ジオクチル、テトラヒドロフタル酸ジ−ｎ−オクチルなど。（ｅ）脂肪酸エステル誘導体
オレイン酸ブチル、グリセリンモノオレイン酸エステル、アセチルリシノール酸メチル、ペンタエリスリトールエステル、ジペンタエリスリトールヘキサエステル、トリアセチン、トリブチリンなど。
（ｆ）オキシ酸エステル系可塑剤
アセチルリシノール酸メチル、アセチルリシノール酸ブチル、ブチルフタリルブチルグリコレート、アセチルクエン酸トリブチルなど。
【００８０】
（ｇ）エポキシ可塑剤
エポキシ化大豆油、エポキシ化アマニ油、エポキシステアリン酸ブチル、エポキシステアリン酸デシル、エポキシステアリン酸オクチル、エポキシステアリン酸ベンジル、エポキシヘキサヒドロフタル酸ジオクチル、エポキシヘキサヒドロフタル酸ジデシルなど。
（ｈ）二価アルコールエステル系可塑剤
ジエチレングリコールジベンゾエート、トリエチレングリコールジ−２−エチルブチラートなど。
（ｉ）含塩素可塑剤
塩素化パラフィン、塩素化ジフェニル、塩素化脂肪酸メチル、メトキシ塩素化脂肪酸メチルなど。
（ｊ）ポリエステル系可塑剤
ポリプロピレンアジペート、ポリプロピレンセバケート、ポリエステル、アセチル化ポリエステルなど。
（ｋ）スルホン酸誘導体
ｐ−トルエンスルホンアミド、ｏ−トルエンスルホンアミド、ｐ−トルエンスルホンエチルアミド、ｏ−トルエンスルホンエチルアミド、トルエンスルホン−Ｎ−エチルアミド、ｐ−トルエンスルホン−Ｎ−シクロヘキシルアミドなど。
（ｌ）クエン酸誘導体
クエン酸トリエチル、アセチルクエン酸トリエチル、クエン酸トリブチル、アセチルクエン酸トリブチル、アセチルクエン酸トリ−２−エチルヘキシル、アセチルクエン酸−ｎ−オクチルデシルなど。
（ｍ）その他
ターフェニル、部分水添ターフェニル、ショウノウ、２−ニトロジフェニル、ジノニルナフタリン、アビエチン酸メチルなど。
【００８１】
各層に添加できる滑剤としては、例えば下記のものが挙げられるがこれらに限定されるものではない。
（ａ）炭化水素系化合物
流動パラフィン、パラフィンワックス、マイクロワックス、低重合ポリエチレンなど。
（ｂ）脂肪酸系化合物
ラウリン酸、ミリスチン酸、パルミチン酸、ステアリン酸、アラキジン酸、ベヘン酸など。
（ｃ）脂肪酸アミド系化合物
ステアリルアミド、パルミチルアミド、オレインアミド、メチレンビスステアロアミド、エチレンビスステアロアミドなど。
（ｄ）エステル系化合物
脂肪酸の低級アルコールエステル、脂肪酸の多価アルコールエステル、脂肪酸ポリグリコールエステルなど。
（ｅ）アルコール系化合物
セチルアルコール、ステアリルアルコール、エチレングリコール、ポリエチレングリコール、ポリグリセロールなど。
（ｆ）金属石けん
ステアリン酸鉛、ステアリン酸カドミウム、ステアリン酸バリウム、ステアリン酸カルシウム、ステアリン酸亜鉛、ステアリン酸マグネシウムなど。
（ｇ）天然ワックス
カルナバロウ、カンデリラロウ、蜜ロウ、鯨ロウ、イボタロウ、モンタンロウなど。
（ｈ）その他
シリコーン化合物、フッ素化合物など。
【００８２】
各層に添加できる紫外線吸収剤として、例えば下記のものが挙げられるがこれらに限定されるものではない。
（ａ）ベンゾフェノン系
２−ヒドロキシベンゾフェノン、２，４−ジヒドロキシベンゾフェノン、２，２，４−トリヒドロキシベンゾフェノン、２，２，４，４−テトラヒドロキシベンゾフェノン、２，２−ジヒドロキシ４−メトキシベンゾフェノンなど。
（ｂ）サルシレート系
フェニルサルシレート、２，４ジ−ｔ−ブチルフェニル３，５−ジ−ｔ−ブチル４ヒドロキシベンゾエートなど。
（ｃ）ベンゾトリアゾール系
（２−ヒドロキシフェニル）ベンゾトリアゾール、（２−ヒドロキシ５−メチルフェニル）ベンゾトリアゾール、（２−ヒドロキシ５−メチルフェニル）ベンゾトリアゾール、（２−ヒドロキシ３−ターシャリブチル５−メチルフェニル）５−クロロベンゾトリアゾールなど。
（ｄ）シアノアクリレート系
エチル−２−シアノ−３，３−ジフェニルアクリレート、メチル２−カルボメトキシ３（パラメトキシ）アクリレートなど。
（ｅ）クエンチャー（金属錯塩系）
ニッケル（２，２チオビス（４−ｔ−オクチル）フェノレート）ノルマルブチルアミン、ニッケルジブチルジチオカルバメート、ニッケルジブチルジチオカルバメート、コバルトジシクロヘキシルジチオホスフェートなど。
（ｆ）ＨＡＬＳ（ヒンダードアミン）
ビス（２，２，６，６−テトラメチル−４−ピペリジル）セバケート、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）セバケート、１−［２−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕エチル］−４−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕−２，２，６，６−テトラメチルピリジン、８−ベンジル−７，７，９，９−テトラメチル−３−オクチル−１，３，８−トリアザスピロ〔４，５〕ウンデカン−２，４−ジオン、４−ベンゾイルオキシ−２，２，６，６−テトラメチルピペリジンなど。
【００８３】
更に、本発明で使用される感光体においては、感光層保護の目的で表面保護層３９が感光層の上に設けられる。この表面保護層（以降、保護層と略記される場合がある）としては、画像形成における感光体１００００回転あたりの摩耗量が０．１μｍ以下の耐摩耗性を有する保護層であることが必須である。
このような保護層３９に使用される材料としてはＡＢＳ樹脂、ＡＣＳ樹脂、オレフィン−ビニルモノマー共重合体、塩素化ポリエーテル、アリル樹脂、フェノール樹脂、ポリアセタール、ポリアミド、ポリアミドイミド、ポリアクリレート、ポリアリルスルホン、ポリブチレン、ポリブチレンテレフタレート、ポリカーボネート、ポリアリレート、ポリエーテルスルホン、ポリエチレン、ポリエチレンテレフタレート、ポリイミド、アクリル樹脂、ポリメチルペンテン、ポリプロピレン、ポリフェニレンオキシド、ポリスルホン、ポリスチレン、ＡＳ樹脂、ブタジエン−スチレン共重合体、ポリウレタン、ポリ塩化ビニル、ポリ塩化ビニリデン、エポキシ樹脂等の樹脂が挙げられる。中でも、ポリカーボネートもしくはポリアリレートが最も良好に使用できる。
また、上記バインダー樹脂の他に、熱硬化型樹脂や光硬化型樹脂を用いることも出来る。熱硬化型樹脂や光硬化型樹脂としては、高い耐摩耗性を発現し、電子写真特性に影響を及ぼさないものであれば、公知のいかなるものも使用できる。特に、分子中に３つ以上の官能基を有する多官能モノマーあるいはオリゴマーを用い、３次元硬化（架橋）させた硬化物からなる保護層は、耐摩耗性が極めて高く、有効に使用することが出来る。
【００８４】
保護層にはその他、耐摩耗性を向上する目的でポリテトラフルオロエチレンのような弗素樹脂、シリコーン樹脂、及びこれらの樹脂に酸化チタン、酸化錫、チタン酸カリウム、シリカ等の無機フィラー、また有機フィラーを分散したもの等を添加することができる。
また、感光体の保護層に用いられるフィラー材料のうち有機性フィラー材料としては、ポリテトラフルオロエチレンのようなフッ素樹脂粉末、シリコーン樹脂粉末、ａ−カーボン粉末等が挙げられ、無機性フィラー材料としては、銅、スズ、アルミニウム、インジウムなどの金属粉末、アルミナ、シリカ、酸化錫、酸化亜鉛、酸化チタン、酸化インジウム、酸化アンチモン、酸化ビスマス、アンチモンをドープした酸化錫、錫をドープした酸化インジウム等の金属酸化物、チタン酸カリウムなどの無機材料が挙げられる。特に、フィラーの硬度の点からは、この中でも無機材料を用いることが有利である。特に、シリカ、酸化チタン、アルミナが有効に使用できる。更に、この中でも六方細密構造を有するα型アルミナが最も有効に使用できる。
【００８５】
保護層中のフィラー濃度は使用するフィラー種により、また感光体を使用する画像形成プロセス条件によっても異なるが、保護層の最表層側において全固形分に対するフィラーの比で５重量％以上、好ましくは１０重量％以上、５０重量％以下、好ましくは３０重量％以下程度が良好である。
また、使用するフィラーの体積平均粒径は、０．１μｍ〜２μｍの範囲が良好に使用され、好ましくは０．３μｍ〜１μｍの範囲である。この場合、平均粒径が小さすぎると耐摩耗性が充分に発揮されず、大きすぎると塗膜の表面性が悪くなったり、塗膜そのものが形成できなかったりするからである。
【００８６】
尚、本発明におけるフィラーの平均粒径とは、特別な記載のない限り体積平均粒径であり、超遠心式自動粒度分布測定装置：ＣＡＰＡ−７００（堀場製作所製）により求めたものである。この際、累積分布の５０％に相当する粒子径（Ｍｅｄｉａｎ系）として算出されたものである。また、同時に測定される各々の粒子の標準偏差が１μｍ以下であることが重要である。これ以上の標準偏差の値である場合には、粒度分布が広すぎて、本発明の効果が顕著に得られなくなってしまう場合がある。
【００８７】
また、本発明で使用するフィラーのｐＨも解像度やフィラーの分散性に大きく影響する。その理由の一つとしては、フィラー、特に金属酸化物は製造時に塩酸等が残存することが考えられる。その残存量が多い場合には、画像ボケの発生は避けられず、またそれは残存量によってはフィラーの分散性にも影響を及ぼす場合がある。
【００８８】
もう一つの理由としては、フィラー、特に金属酸化物の表面における帯電性の違いによるものである。通常、液体中に分散している粒子はプラスあるいはマイナスに帯電しており、それを電気的に中性に保とうとして反対の電荷を持つイオンが集まり、そこで電気二重層が形成されることによって粒子の分散状態は安定化している。粒子から遠ざかるに従いその電位（ゼータ電位）は徐々に低くなり、粒子から充分に離れて電気的に中性である領域の電位はゼロとなる。従って、ゼータ電位の絶対値の増加によって粒子の反発力が高くなることによって安定性は高くなり、ゼロに近づくに従い凝集しやすく不安定になる。一方、系のｐＨ値によってゼータ電位は大きく変動し、ある ｐＨ値において電位はゼロとなり等電点を持つことになる。従って、系の等電点からできるだけ遠ざけて、ゼータ電位の絶対値を高めることによって分散系の安定化が図られることになる。
【００８９】
本発明の構成においては、フィラーとしては前述の等電点におけるｐＨが、少なくとも５以上を示すものが画像ボケ抑制の点から好ましく、より塩基性を示すフィラーであるほどその効果が高くなる傾向があることが確認された。等電点におけるｐＨが高い塩基性を示すフィラーは、系が酸性であったほうがゼータ電位はより高くなることにより、分散性及びその安定性は向上することになる。
ここで、本発明におけるフィラーのｐＨは、ゼータ電位から等電点におけるｐＨ値を記載した。この際、ゼータ電位の測定は、大塚電子（株）製レーザーゼータ電位計にて測定した。
【００９０】
更に、画像ボケが発生しにくいフィラーとしては、電気絶縁性が高いフィラー（比抵抗が１０^１０Ω・ｃｍ以上）が好ましく、フィラーのｐＨが５以上を示すものやフィラーの誘電率が５以上を示すものが特に有効に使用できる。また、ｐＨが５以上のフィラーあるいは誘電率が５以上のフィラーを単独で使用することはもちろん、ｐＨが５以下のフィラーとｐＨが５以上のフィラーとを２種類以上を混合したり、誘電率が５以下のフィラーと誘電率が５以上のフィラーとを２種類以上混合したりして用いることも可能である。また、これらのフィラーの中でも高い絶縁性を有し、熱安定性が高い上に、耐摩耗性が高い六方細密構造であるα型アルミナは、画像ボケの抑制や耐摩耗性の向上の点から特に有用である。
【００９１】
本発明において使用するフィラーの比抵抗は以下のように定義される。フィラーのような粉体は、充填率によりその比抵抗値が異なるので、一定の条件下で測定する必要がある。本発明においては、特開平５−９４０４９号公報、特開平５−１１３６８８号公報に示された測定装置と同様の構成の装置を用いて、フィラーの比抵抗値を測定し、この値を用いた。測定装置において、電極面積は４．０ｃｍ^２である。測定前に片側の電極に４ｋｇの荷重を１分間かけ、電極間距離が４ｍｍになるように試料量を調節する。測定の際は、上部電極の重量（１Ｋｇ）の荷重状態で測定を行ない、印加電圧は１００Ｖにて測定する。１０^６Ω・ｃｍ以上の領域は、ＨＩＧＨ ＲＥＳＩＳＴＡＮＣＥ ＭＥＴＥＲ（横河ヒューレットパッカード）、それ以下の領域についてはデジタルマルチメーター（フルーク）により測定した。これにより得られた比抵抗値を本発明でいうところの比抵抗値と定義するものである。
フィラーの誘電率は以下のように測定した。上述のような比抵抗の測定と同様なセルを用い、荷重をかけた後に、静電容量を測定し、これより誘電率を求めた。静電容量の測定は、誘電体損測定器（安藤電気）を使用した。
【００９２】
更に、これらのフィラーは少なくとも一種の表面処理剤で表面処理させることが可能であり、そうすることがフィラーの分散性の面から好ましい。フィラーの分散性の低下は残留電位の上昇だけでなく、塗膜の透明性の低下や塗膜欠陥の発生、さらには耐摩耗性の低下をも引き起こすため、高耐久化あるいは高画質化を妨げる大きな問題に発展する可能性がある。表面処理剤としては、従来用いられている表面処理剤すべてを使用することができるが、フィラーの絶縁性を維持できる表面処理剤が好ましい。例えば、チタネート系カップリング剤、アルミニウム系カップリング剤、ジルコアルミネート系カップリング剤、高級脂肪酸等、あるいはこれらとシランカップリング剤との混合処理や、Ａｌ_２Ｏ_３、ＴｉＯ_２、ＺｒＯ_２、シリコーン、ステアリン酸アルミニウム等、あるいはそれらの混合処理がフィラーの分散性及び画像ボケの点からより好ましい。シランカップリング剤による処理は、画像ボケの影響が強くなるが、上記の表面処理剤とシランカップリング剤との混合処理を施すことによりその影響を抑制できる場合がある。表面処理量については、用いるフィラーの平均一次粒径によって異なるが、３〜３０ｗｔ％が適しており、５〜２０ｗｔ％がより好ましい。表面処理量がこれよりも少ないとフィラーの分散効果が得られず、また多すぎると残留電位の著しい上昇を引き起こす。これらフィラ−材料は単独もしくは２種類以上混合して用いられる。フィラーの表面処理量に関しては、上述のようにフィラー量に対する使用する表面処理剤の重量比で定義される。
【００９３】
これらフィラー材料は、適当な分散機を用いることにより分散できる。また、保護層の透過率の点から使用するフィラーは１次粒子レベルまで分散され、凝集体が少ないほうが好ましい。
【００９４】
また、保護層３９には残留電位低減、応答性改良のため、電荷輸送物質を含有しても良い。電荷輸送物質は、電荷輸送層の説明のところに記載した材料を用いることができる。電荷輸送物質として、低分子電荷輸送物質を用いる場合には、保護層中における濃度傾斜を設けても構わない。耐摩耗性向上のため、表面側を低濃度にすることは有効な手段である。ここでいう濃度とは、保護層を構成する全材料の総重量に対する低分子電荷輸送物質の重量の比を表わし、濃度傾斜とは上記重量比において表面側において濃度が低くなるような傾斜を設けることを示す。
また、保護層には電荷輸送物質としての機能とバインダー樹脂の機能を持った高分子電荷輸送物質も良好に使用される。これら高分子電荷輸送物質から構成される保護層は耐摩耗性に優れるだけでなく、繰り返し使用における画像ボケの発生を低減化させる効果もあり、本発明において非常に有用である。高分子電荷輸送物質としては、公知の材料が使用できるが、特に、トリアリールアミン構造を主鎖および／または側鎖に含むポリカーボネートが良好に用いられる。中でも、（Ｉ）〜（Ｘ）式で表される高分子電荷輸送物質が良好に用いられ、これらを以下に例示し、具体例を示す。
【００９５】
（Ｉ）式
【化９】

式中、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基又はハロゲン原子、Ｒ_４は水素原子又は置換もしくは無置換のアルキル基、Ｒ_５、Ｒ_６は置換もしくは無置換のアリール基、ｏ、ｐ、ｑはそれぞれ独立して０〜４の整数、ｋ、ｊは組成を表し、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表し５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表される２価基を表す。尚、（Ｉ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【００９６】
【化１０】

Ｒ_１０１、Ｒ_１０２は各々独立して置換もしくは無置換のアルキル基、アリール基またはハロゲン原子を表す。ｌ、ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状もしくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中Ｚは脂肪族の２価基を表す。）または、
【化１１】

式中、ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ₁₀₃、Ｒ₁₀₄は置換または無置換のアルキル基又はアリール基を表わす。ここで、Ｒ₁₀₁とＲ₁₀₂、Ｒ₁₀₃とＲ₁₀₄は、それぞれ同一でも異なってもよい。
【００９７】
（II）式
【化１２】

式中、Ｒ_７, Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１, Ａｒ_２, Ａｒ_３は同一又は異なるアリレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（II）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【００９８】
（III）式
【化１３】

式中、Ｒ_９, Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４，Ａｒ_５，Ａｒ_６は同一又は異なるアリレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（III）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【００９９】
（IV）式
【化１４】

式中、Ｒ_１１, Ｒ_１２ は置換もしくは無置換のアリール基、Ａｒ_７, Ａｒ₈, Ａｒ₉は同一又は異なるアリレン基、ｐは１〜５の整数を表す。 Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（IV）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１００】
（Ｖ）式
【化１５】

式中、Ｒ_１３，Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０，Ａｒ_１１，Ａｒ_１２は同一又は異なるアリレン基、 Ｘ_１，Ｘ_２ は置換もしくは無置換のエチレン基、又は置換もしくは無置換のビニレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（Ｖ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１０１】
（VI）式
【化１６】

式中、Ｒ_１５，Ｒ_１６，Ｒ_１７，Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３， Ａｒ_１４，Ａｒ_１５，Ａｒ_１６は同一又は異なるアリレン基、 Ｙ_１，Ｙ_２，Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表し同一であっても異なってもよい。 Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（VI）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１０２】
（VII）式
【化１７】

式中、Ｒ_１９，Ｒ_２０ は水素原子、置換もしくは無置換のアリール基を表し，Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７，Ａｒ_１８，Ａｒ_１９ は同一又は異なるアリレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（I）式の場合と同じである。尚、（VII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１０３】
（VIII）式
【化１８】

式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０，Ａｒ_２１，Ａｒ_２２，Ａｒ_２３ は同一又は異なるアリレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（VIII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１０４】
（IX）式
【化１９】

式中、Ｒ_２２，Ｒ_２３，Ｒ_２４，Ｒ_２５ は置換もしくは無置換のアリール基、Ａｒ_２４，Ａｒ_２５，Ａｒ_２６，Ａｒ_２７， Ａｒ_２８は同一又は異なるアリレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（I）式の場合と同じである。尚、（IX）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１０５】
（Ｘ）式
【化２０】

式中、Ｒ_２６，Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９，Ａｒ_３０，Ａｒ_３１は同一又は異なるアリレン基を表す。 Ｘ，ｋ，ｊおよびｎは、（I）式の場合と同じである。尚、（Ｘ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。
【０１０６】
また、保護層に使用される高分子電荷輸送物質として、上述の高分子電荷輸送物質の他に、電荷輸送層の成膜時には電子供与性基を有するモノマーあるいはオリゴマーの状態で、成膜後に硬化反応あるいは架橋反応をさせることで、最終的に２次元あるいは３次元の架橋構造を有する重合体も含むものである。
これら電子供与性基を有する重合体から構成される保護層、あるいは架橋構造を有する重合体は耐摩耗性に優れたものである。通常、画像形成装置においては、帯電電位（未露光部電位）は一定であるため、繰り返し使用により感光体の表面層が摩耗すると、その分だけ感光体にかかる電界強度が高くなってしまう。この電界強度の上昇に伴い、地汚れの発生頻度が高くなるため、感光体の耐摩耗性が高いことは、地汚れに対して有利である。これら電子供与性基を有する重合体から構成される保護層は、自身が高分子化合物であるため成膜性に優れ、低分子分散型高分子からなる保護層に比べ、電荷輸送部位を高密度に構成することが可能で電荷輸送能に優れたものである。このため、高分子電荷輸送物質を用いた保護層を有する感光体には高速応答性が期待できる。
その他の電子供与性基を有する重合体としては、公知単量体の共重合体や、ブロック重合体、グラフト重合体、スターポリマーや、また、例えば特開平３−１０９４０６号公報、特開２０００−２０６７２３号公報、特開２００１−３４００１号公報等に開示されているような電子供与性基を有する架橋重合体などを用いることも可能である。この場合にも、先の移動度を満足できるような材料が有効に使用出来る。
【０１０７】
保護層の形成法としては通常の湿式塗工法が採用される。なお保護層の厚さは０．１〜１０μｍ程度が適当である。また、以上のほかに真空薄膜作成法にて形成したａ−Ｃ、ａ−ＳｉＣなど公知の材料を保護層として用いることができる。次に、本発明に用いられる現像剤（有色トナー、透明トナー、白色トナーおよびキャリア）について述べる。本発明で使用される現像剤は、トナーのみからなる１成分系現像剤、トナーとキャリアから構成される２成分系現像剤のいずれも良好に使用できる。
本発明の静電潜像現像用キャリアと共に現像剤を構成するトナーとしては、従来公知の方法で製造されたものを使用できる。バインダー樹脂、着色剤及び極性制御剤よりなる混合物を熱ロールミルで溶融混練した後、冷却固化せしめ、これを粉砕分級して得られる。具体的には、バインダー樹脂、着色剤、荷電制御剤、必要に応じて任意の添加物などから構成される。
【０１０８】
バインダー樹脂としては、例えば、ポリスチレン、ポリ−ｐ−スチレン、ポリビニルトルエン等のスチレン及びその置換体の単重合体、スチレン−ｐ−クロルスチレン共重合体、スチレン−プロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−アクリル酸メチル重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−メタクリル酸メチル共重合体、スチレン−メタクリル酸エチル共重合体、スチレン−メタクリル酸ブチル共重合体、スチレン−α−クロルメタクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体等のスチレン系共重合体、ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ塩化ビニル、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリエステル、ポリウレタン、ポリアミド、エポキシ樹脂、ポリビニルブチラール、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂、脂肪族炭化水素樹脂、芳香族系石油樹脂、塩素化パラフィン、パラフィンワックスなどが、単独あるいは混合して使用できる。
【０１０９】
また、トナーに用いられる極性制御剤として、以下のものが挙げられる。
トナーを負荷電性に制御する極性制御剤としては、例えば有機金属錯体、キレート化合物が有効であり、モノアゾ金属錯体、アセチルアセトン金属錯体、芳香族ハイドロキシカルボン酸系金属錯体、芳香族ダイカルボン酸系金属錯体があげられる。他には、芳香族ハイドロキシカルボン酸、芳香族モノ及びポリカルボン酸及びその金属塩、その無水物、そのエステル類、ビスフェノールの如きフェノール誘導体類がある。
【０１１０】
トナーを正荷電性に制御する極性制御剤としては、ニグロシン及び脂肪酸金属塩による変性物；トリブチルベンジルアンモニウム−１−ヒドロキシ−４−ナフトスルフォン酸塩、テトラブチルアンモニウムテトラフルオロボレートの如き四級アンモニウム塩、及びこれらの類似体であるホスホニウム塩の如きオニウム塩及びこれらのレーキ顔料、トリフェニルメタン染料及びこれらのレーキ顔料（レーキ化剤としては、燐タングステン酸、燐モリブデン酸、燐タングステンモリブデン酸、タンニン酸、ラウリン酸、没食子酸、フェリシアン化物、フェロシアン化物）が挙げられる。
【０１１１】
トナーに使用される極性制御剤の使用量は、バインダー樹脂の種類、必要に応じて使用される添加剤の有無、分散方法を含めたトナー製造方法によって決定されるもので、一義的に限定されるものではないが、好ましくはバインダー樹脂１００重量部に対して、０．１〜２０重量部の範囲で用いられる。０．１重量部未満では、トナーの帯電量が不足し実用的でない。また、２０重量部を越える場合には、トナーの帯電量が大きすぎ、キャリアとの静電的吸引力の増大のため、現像剤の流動性低下や、画像濃度の低下を招く。
【０１１２】
トナーに含有される黒色の着色剤としては、例えば、カーボンブラック、アニリンブラック、ファーネスブラック、ランプブラック等が使用できる。シアンの着色剤としては、例えば、フタロシアニンブルー、メチレンブルー、ビクトリアブルー、メチルバイオレット、アニリンブルー、ウルトラマリンブルー等が使用できる。マゼンタの着色剤としては、例えば、ローダミン６Ｇレーキ、ジメチルキナクリドン、ウォッチングレッド、ローズベンガル、ローダミンＢ、アリザリンレーキ等が使用できる。イエローの着色剤としては、例えば、クロムイエロー、ベンジジンイエロー、ハンザイエロー、ナフトールイエロー、モリブデンオレンジ、キノリンイエロー、タートラジン等が使用できる。
【０１１３】
透明トナーの場合には、上記の着色剤をトナー中に添加しないことで、透明トナーを構成することが出来る。また透明トナーには、後述の各種添加剤を用いることが出来るが、いずれも透明トナーの特性（透明性）を阻害しないように、トナーの状態で透明性を維持できる添加剤が使用される。
白色トナーの場合には、有色トナーで使用される着色剤の代わりに白色の着色剤が使用される。例えば、酸化チタン、酸化亜鉛、硫酸バリウム、アルミナ、炭酸カルシウムなどが挙げられる。
【０１１４】
本発明で用いるトナー粒子には、結着樹脂と着色剤の他に、必要に応じて、オフセット防止のための離型剤を添加することができる。離型剤としては、低分子量ポリプロピレン、低分子量ポリエチレン等のワックス類が挙げられる。
本発明に用いられるワックスは、エステル系もしくはオレフィン系が望ましい。これらワックスは、使用するバインダー樹脂に対し、一般的には非相溶性を示し、バインダー中に微分散されやすい。エステル系ワックスとは、エステル結合を有するものであり、例えば、カルナウバワックス、キャンデリラワックス、ライスワックス等の天然ワックス、及びモンタンワックス等が挙げられる。オレフィンワックスとしては、ポリエチレンワックス、ポリプロピレンワックス等の合成ワックスが挙げられる。
【０１１５】
バインダー樹脂の中で前記ワックスの平均分散径は、０．２〜５．０μｍが望ましい。０．２μｍより小さいとワックスの染みだし効果が得られず、本発明の効果が発現しにくい。また、０．２μｍ以下に分散するためには、溶融混練時にバインダー樹脂に過剰な分散エネルギーを加える必要があり、樹脂の分子が切断され、本来の機能を失う場合がある。また、５．０μｍより大きくなると、トナーの定着性、流動性、保存性、耐久性等を悪化させてしまう。
また、ワックスの添加量はバインダー樹脂に対して、１０重量％以下が適当である。これ以上になると、トナーの流動性、オフセット性が悪くなる。
更に、トナーに磁性材料を含有させ、磁性トナーとしても使用し得る。磁性トナー中に含まれる磁性材料としては、マグネタイト、ヘマタイト、フェライト等の酸化鉄、鉄、コバルト、ニッケルのような金属あるいはこれらの金属とアルミニウム、コバルト、銅、鉛、マグネシウム、スズ、亜鉛、アンチモン、ベリリウム、ビスマス、カドミウム、カルシウム、マンガン、セレン、チタン、タングステン、バナジウムのような金属の合金及びその混合物などが挙げられる。これらの強磁性体は平均粒径が０．０５〜２μｍ程度のものが望ましく、トナー中に含有させる量としては、樹脂成分１００重量部に対し約２０〜２００重量部、特に好ましくは、樹脂成分１００重量部に対し４０〜１５０重量部である。
【０１１６】
また、現像剤に添加する滑剤としては、ＰＴＦＥ、ＰＦＡ、ＰＶＤＦ等の各種フッ素含有樹脂、シリコーン樹脂、ポリオレフィン系樹脂、ステアリン酸亜鉛、ラウリル酸亜鉛、ミリスチン酸亜鉛、ステアリン酸カルシウム、ステアリン酸アルミニウム等の脂肪酸金属塩などが挙げられる。中でも、ステアリン酸亜鉛が最も好ましい。現像剤中への滑剤添加量は、現像剤中のトナーに対して０．００１〜０．２重量％の範囲が望ましい。
【０１１７】
また、現像剤に添加する流動化剤としては、例えば、コロイド状シリカ、疎水性シリカ、テフロン（登録商標）、フルオロポリマー、低分子量ポリオレフィン、脂肪酸金属塩（ステアリン酸亜鉛、ステアリン酸アルミニウム、ステアリン酸カルシウムなど）、金属酸化物（酸化チタン、酸化アルミニウム、酸化錫、酸化アンチモンなど）、導電性付与剤（カーボンブラック、酸化錫など）、磁性体、更にそれら添加物を表面処理したものなど、が挙げられる。その中でも、シリカ、チタニア、アルミナ、酸化セリウム、チタン酸ストロンチウム、炭酸カルシウム、炭酸マグウネシウム及びりん酸カルシウム等の無機微粒子、フッ素含有樹脂微粒子、シリカ含有樹脂微粒子及び窒素含有樹脂微粒子等の有機樹脂微粒子が好ましい。これら流動化剤は、１種または２種以上を合わせて用いてよく、含有量は一般にトナー１００部に対して、０．１〜１０重量部が適切である。また、目的に応じて外部添加剤表面に表面処理を施してもよい。表面処理剤としては、疎水化処理を行うためのシラン化合物、シランカップリング剤、シリコーンオイル等が挙げられる。
【０１１８】
さらに、２種以上の粒径の異なる外部添加剤を含有することが好ましく、平均粒径で２〜５倍程度の粒径差のある外部添加剤を含有することが好ましい。２種以上の粒径の異なる外部添加剤を含有しない場合は、経時での外部添加剤のトナー母体への埋没が急激に進み、トナー流動性の悪化が急激に進んでしまう。従って、トナーの流動性が低下することによる画像ムラが発生しやすく、またトナーへの付着力が強くなり難く、トナーからの脱離が容易に起こり、感材傷、画像ぬけの原因となる。２種以上の粒径の異なる外部添加剤を含有すれば、大粒径外部添加剤がスペーサーの役割を果たし、トナー流動性に効果がある小粒径外部添加剤のトナー母体への埋没が防止され、トナー流動性を維持できる。
【０１１９】
以上のように構成されるトナーは、有色トナー、透明トナー及び白色トナーにおいては、着色剤の有無及び使用される着色剤の色を除き、同様の構成であることが望ましい。特に、ワックス類を使用する場合、および流動化剤を使用する場合は、感光体の摩耗量に影響を及ぼすため、有色トナー、透明トナー及び白色トナーに含有される両者の量はほぼ同一であることが重要である。
ワックス類を使用する場合、感光体表面にワックス類が転移して、クリーニング部における感光体表面の摩耗量を低減する働きがある。このため、有色トナー、透明トナー及び白色トナー中に含有されるワックス類の添加量がほぼ同一の場合、繰り返し使用における感光体の摩耗量が小さい方向で均一化される。ワックス類を使用する場合の副作用としては、感光体表面へのトナーフィルミングや画像ボケが発生しうる。このため、感光体表面の組成にも依存するが、このような現象が起こらないようにプロセス条件を決定する必要がある。
【０１２０】
滑剤を使用する場合、感光体表面に滑剤が付着し、クリーニング部における残留トナーのクリーニング性を向上させると共に、感光体表面の摩耗量を低減する働きがある。このため、有色トナー、透明トナー及び白色トナー中に含有される滑剤の添加量がほぼ同一の場合、繰り返し使用における感光体の摩耗量が小さい方向で均一化される。滑剤を使用する場合の副作用としては、画像ボケが発生しうる。このため、感光体表面の組成にも依存するが、このような現象が起こらないようにプロセス条件を決定する必要がある。
流動化剤を使用する場合、感光体表面に流動化剤が付着し、転写残の流動化剤がクリーニング部に到達すると、感光体の摩耗を促進する働きがある。このため、有色トナー、透明トナー及び白色トナー中に含有される流動化剤の添加量がほぼ同一の場合、繰り返し使用における感光体の摩耗量が大きい方向で均一化される。流動化剤を使用する場合の副作用としては、感光体表面摩耗量が大きくなり、スジなどの異常画像の発生および感光体寿命の低下が発生しうる。このため、感光体表面の組成にも依存するが、このような現象が起こらないようにプロセス条件を決定する必要がある。
【０１２１】
本発明に使用しうるキャリアとしては、例えば鉄粉、フェライト粉、ニッケル粉の如き磁性を有する粉体及びその表面を樹脂等で処理したものなどがあげられる。本 発明に用いられるトナーの摩擦帯電性をより安定化させ、潜像を忠実に現像させるために本発明に用いられるキャリアは、樹脂及び／またはシリコーン化合物で被覆してあることが好ましい。これによって、トナーの荷電制御を目的として行うこともできる。
キャリアの被覆層を形成するための樹脂としては、例えばシリコーン系化合物、フッ素系樹脂等を好ましく用いることができる。キャリアの被覆層を形成するためのフッ素系樹脂としては、例えば、ポリフッ化ビニル、ポリフッ化ビニリデン、ポリトリフルオロエチレン、ポリトリフルオルクロルエチレンのようなパーフルオロポリマー、ポリテトラフルオロエチレン、ポリパーフルオルプロピレン、フッ化ビニリデンとアクリル単量体との共重合体、フッ化ビニリデンとトリフルオルクロルエチレンとの共重合体、テトラフルオロエチレンとヘキサフルオロプロピレンとの共重合体、フッ化ビニルとフッ化ビニリデンとの共重合体、フッ化ビニリデンとテトラフルオロエチレンとの共重合体、フッ化ビニリデンとヘキサフルオロプロピレンとの共重合体、テトラフルオロエチレンとフッ化ビニリデン及び非フッ素化単量体のターポリマーのようなフルオロターポリマー等が好ましく用いられる。キャリアの被覆層の形成においては、上記の如きフッ素系樹脂をそれぞれ単独で用いてもよいし、あるいはこれらをブレンドしたものを用いてもよい。また、これらにさらにその他の重合体をブレンドしたものを用いてもよい。
【０１２２】
また、キャリアの被覆層を形成するためのシリコーン系化合物としては、ポリシロキサン、例えばジメチルポリシロキサン、フェニルメチルポリシロキサン等が全て用いられ、また、アルキド変性シリコーン、エポキシ変性シリコーン、ポリエステル変性シリコーン、ウレタン変性シリコーン、アクリル変性シリコーン等の変性樹脂も使用可能である。また、変性形態として、ブロック共重合体、グラフト共重合体、くし形グラフトポリシロキサン等いずれも使用可能である。
実際の磁性粒子表面への塗布に際しては、上記樹脂を浸漬法あるいは流動床法等により磁性粒子に噴霧する方法等がとられる。
【０１２３】
本発明に使用されるキャリアの芯材の材質としては、例えば、表面酸化または未酸化の鉄、ニッケル、コバルト、マンガン、クロム、希土類等の金属及びそれらの合金または酸化物などが使用できるが、好ましくは金属酸化物、より好ましくはフェライト粒子が使用できる。また、その製造方法としては、特別な制約はない。本発明のキャリア並びにトナーの使用量としては、トナー粒子がキャリア粒子のキャリア表面に付着して、その表面積の３０〜９０％を占める程度に両粒子を混合するのが好ましい。
【０１２４】
【実施例】
以下、本発明を実施例を挙げて説明するが、本発明が実施例により制約を受けるものではない。なお、部はすべて重量部である。
＜チタニルフタロシアニンＡの合成＞
１,３−ジイミノイソインドリン２９２ｇとスルホラン２０００ｍｌを混合し、窒素気流下でチタニウムテトラブトキシド２０．４ｇを滴下する。滴下終了後、徐々に１８０℃まで昇温し、反応温度を１７０℃〜１８０℃の間に保ちながら５時間撹拌して反応を行なった。反応終了後、放冷した後析出物を濾過し、クロロホルムで粉体が青色になるまで洗浄し、つぎにメタノールで数回洗浄し、さらに８０℃の熱水で数回洗浄した後乾燥し、粗チタニルフタロシアニンを得た。粗チタニルフタロシアニンを２０倍量の濃硫酸に溶解し、１００倍量の氷水に撹拌しながら滴下し、析出した結晶をろ過、ついで洗浄液が中性になるまで水洗いを繰り返し、チタニルフタロシアニン顔料のウェットケーキを得た。得られたこのウェットケーキ２０ｇをテトラヒドロフラン２００ｇに投入し、４時間攪拌を行なった後、濾過を行ない、乾燥して、チタニルフタロシアニンＡ粉末を得た。
【０１２５】
＜チタニルフタロシアニンＢの合成＞
チタニルフタロシアニンＡの合成過程と同様に粗チタニルフタロシアニンを得、更に同様に濃硫酸によるアシッドペースト処理により、チタニルフタロシアニン顔料のウェットケーキを得た。得られたウェットケーキ２０ｇを２−ブタノン２００ｇに投入し、４時間の撹拌を行なった後、濾過を行ない、乾燥して、チタニルフタロシアニンＢ粉末を得た。
【０１２６】
＜チタニルフタロシアニンＣの合成＞
上述のように合成したチタニルフタロシアニンＢ粉末２０ｇを、テトラヒドロフラン２００ｇと共にボールミリング処理を２４時間行なった後、濾過を行ない、乾燥して、チタニルフタロシアニンＣ粉末を得た。
以上のように合成したチタニルフタロシアニンＡ、Ｂ、Ｃは、下記の測定条件により、Ｘ線回折スペクトルを測定した。
【０１２７】
（Ｘ線回折スペクトル測定条件）
Ｘ線管球：Ｃｕ
電圧：５０ｋＶ
電流：３０ｍＡ
走査速度：２°／分
走査範囲：３°〜４０°
時定数：２秒
【０１２８】
チタニルフタロシアニンＡ、Ｂ、ＣのＸ線回折スペクトルを図９〜１１に示す。
図９から、チタニルフタロシアニンＡのＸ線回折スペクトルは、Ｃｕ−Ｋα線（波長１．５４２Å）に対するブラッグ角２θが２７．２±０.２°に最大ピークを有し、更に９．４゜、９．６゜、２４．０゜に主要なピークを有し、かつ最も低角側の回折ピークとして７．３゜にピークを有し、７．３゜のピークと９．４゜のピークの間にピークを有さず、かつ２６．３゜にピークを有さないものであることが分かる。
【０１２９】
図１０から、チタニルフタロシアニンＢのＸ線回折スペクトルは、Ｃｕ−Ｋα線（波長１．５４２Å）に対するブラッグ角２θが２７．２±０.２°に最大ピークを有し、かつ最も低角側の回折ピークとして７．５゜にピークを有するものであることが分かる。
【０１３０】
図１１から、チタニルフタロシアニンＢのＸ線回折スペクトルは、Ｃｕ−Ｋα線（波長１．５４２Å）に対するブラッグ角２θが２６．３±０.２°に最大ピークを有するものであることが分かる。
このように、チタニルフタロシアニンＡ、Ｂ、Ｃは、それぞれ結晶型の異なるチタニルフタロシアニンであることが分かる。
【０１３１】
＜感光体１の作製＞
長さ３４０ｍｍ、直径３０ｍｍのアルミニウムシリンダー（ＪＩＳ３０１０）上に下記組成の下引き層塗工液、電荷発生層塗工液、電荷輸送層塗工液および保護層塗工液を、順次塗布・乾燥し、３．５μｍの中間層、０．２μｍの電荷発生層、２０μｍの電荷輸送層、５μｍの保護層からなる電子写真感光体を形成した。
◎下引き層塗工液
二酸化チタン粉末 ４００部
メラミン樹脂 ６５部
アルキッド樹脂 １２０部
２−ブタノン ４００部
【０１３２】
◎電荷発生層塗工液
下記構造のジスアゾ顔料 ８部
【化２１】

ポリビニルブチラール ５部
２−ブタノン ２００部
シクロヘキサノン ４００部
【０１３３】
◎電荷輸送層塗工液
下記構造のポリカーボネート １０部
【化２２】

（粘度平均分子量は約５万である。）
【０１３４】
下記構造式の電荷輸送物質 ７部
【化２３】

テトラヒドロフラン ８０部
【０１３５】
◎保護層塗工液
下記構造のポリカーボネート １０部
【化２４】

（粘度平均分子量は約５万である。）
下記構造式の電荷輸送物質 ７部
【０１３６】
【化２５】

α―アルミナ微粒子（比抵抗：２．５×１０^１２Ω・ｃｍ、
平均一次粒径：０．４μｍ） ６部
シクロヘキサノン １５０部
テトラヒドロフラン ５００部
【０１３７】
＜感光体２の作製＞
感光体１の作製において、保護層を設けず、電荷輸送層の膜厚を２５μｍに変更した以外は、感光体１の作製と同様に感光体を作製した。
【０１３８】
＜感光体３の作製＞
感光体１の作製において、保護層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
◎保護層塗工液
下記構造式の高分子電荷輸送物質 １５部
【０１３９】
【化２６】

（ＧＰＣで分子量を測定した結果、ｎはおよそ２３０であった。）
シクロヘキサノン １５０部
テトラヒドロフラン ５００部
【０１４０】
＜感光体４の作製＞
感光体１の作製において、保護層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
◎保護層塗工液
下記構造のポリカーボネート １３部
【化２７】

（粘度平均分子量は約５万である。）
下記構造式の電荷輸送物質 ８部
【０１４１】
【化２８】

α―アルミナ微粒子（比抵抗：２．５×１０^１２Ω・ｃｍ、
平均一次粒径：０．４μｍ） １部
シクロヘキサノン ２００部
テトラヒドロフラン ６００部
【０１４２】
＜感光体５の作製＞
感光体１の作製において、保護層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
【０１４３】
◎保護層塗工液
下記構造のポリカーボネート １０部
【化２９】

（粘度平均分子量は約５万である。）
【０１４４】
下記構造式の電荷輸送物質 ７部
【化３０】

シリカ微粉末（比抵抗：４×１０^１３Ω・ｃｍ、
平均一次粒径：０．３μｍ） ８部
シクロヘキサノン １５０部
テトラヒドロフラン ５００部
【０１４５】
＜感光体６の作製＞
感光体１の作製において、保護層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
【０１４６】
◎保護層塗工液
下記構造のポリカーボネート １０部
【化３１】

（粘度平均分子量は約５万である。）
【０１４７】
下記構造式の電荷輸送物質 ７部
【化３２】

酸化チタン微粒子（比抵抗：１．５×１０^１０Ω・ｃｍ、
平均一次粒径：０．５μｍ） ７部
シクロヘキサノン １５０部
テトラヒドロフラン ５００部
【０１４８】
＜感光体７の作製＞
感光体１の作製において、保護層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
【０１４９】
◎保護層塗工液
下記構造のポリカーボネート １０部
【化３３】

（粘度平均分子量は約５万である。）
下記構造式の電荷輸送物質 ７部
【０１５０】
【化３４】

酸化錫−酸化アンチモン粉末（比抵抗：１０^６Ω・ｃｍ、
平均１次粒径０．４μｍ） ６部
シクロヘキサノン １５０部
テトラヒドロフラン ５００部
【０１５１】
＜感光体８の作製＞
感光体１の作製において、保護層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
【０１５２】
◎保護層塗工液
下記構造式の高分子電荷輸送物質 １７部
【化３５】

（ＧＰＣで分子量を測定した結果、ｎはおよそ２５０であった。）
α―アルミナ微粒子（比抵抗：２．５×１０^１２Ω・ｃｍ、
平均一次粒径：０．４μｍ） ６部
シクロヘキサノン ３００部
テトラヒドロフラン ８００部
【０１５３】
＜感光体９の作製＞
感光体１の作製において、電荷発生層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
◎電荷発生層塗工液
下記構造のジスアゾ顔料 ８部
【化３６】

ポリビニルブチラール ５部
２−ブタノン ２００部
シクロヘキサノン ４００部
【０１５４】
＜感光体１０の作製＞
感光体１の作製において、電荷発生層塗工液を以下のものに変更した以外は、感光体１と同様に感光体を作製した。
◎電荷発生層塗工液
下記構造のジスアゾ顔料 ８部
【化３７】

ポリビニルブチラール ５部
２−ブタノン ２００部
シクロヘキサノン ４００部
【０１５５】
＜感光体１１の作製＞
直径３０ｍｍのアルミニウムシリンダー（ＪＩＳ３０１０）上に下記組成の下引き層塗工液、電荷発生層塗工液、電荷輸送層塗工液および保護層塗工液を、順次塗布・乾燥し、３．５μｍの中間層、０．２μｍの電荷発生層、２０μｍの電荷輸送層、５μｍの保護層からなる電子写真感光体を形成した。
◎下引き層塗工液
二酸化チタン粉末 ４００部
メラミン樹脂 ６５部
アルキッド樹脂 １２０部
２−ブタノン ４００部
【０１５６】
◎電荷発生層塗工液
先に合成したチタニルフタロシアニンＡ １５部
ポリビニルブチラール １０部
２−ブタノン ２８０部
【０１５７】
◎電荷輸送層塗工液
下記構造のポリカーボネート １０部
【化３８】

（粘度平均分子量は約５万である。）
【０１５８】
下記構造式の電荷輸送物質 ７部
【化３９】

テトラヒドロフラン ８０部
【０１５９】
◎保護層塗工液
下記構造のポリカーボネート １０部
【化４０】

（粘度平均分子量は約５万である。）
【０１６０】
下記構造式の電荷輸送物質 ７部
【化４１】

α―アルミナ微粒子（比抵抗：２．５×１０^１２Ω・ｃｍ、
平均一次粒径：０．４μｍ） ６部
シクロヘキサノン １５０部
テトラヒドロフラン ５００部
【０１６１】
＜感光体１２の作製＞
感光体１１の作製において、アルミニウムシリンダー（ＪＩＳ１０５０）を以下の陽極酸化皮膜処理を行い、次いで下引き層を設けずに、感光体１１と同様に電荷発生層、電荷輸送層、保護層を設け、感光体を作製した。
【０１６２】
◎陽極酸化皮膜処理
支持体表面の鏡面研磨仕上げを行い、脱脂洗浄、水洗浄を行った後、液温２０゜C、硫酸１５ｖｏｌ％の電解浴に浸し、電解電圧１５Ｖにて３０分間陽極酸化皮膜処理を行った。更に、水洗浄を行った後、７％の酢酸ニッケル水溶液（５０゜C）にて封孔処理を行った。その後純水による洗浄を経て、６μｍの陽極酸化皮膜が形成された支持体を得た。
【０１６３】
＜感光体１３の作製＞
感光体１１の作製において、電荷発生層塗工液を以下のものに変更した以外は、感光体１１と同様に感光体を作製した。
【０１６４】
◎電荷発生層塗工液
先に合成したチタニルフタロシアニンＢ １５部
ポリビニルブチラール １０部
２−ブタノン ２８０部
【０１６５】
＜感光体１４の作製＞
感光体１１の作製において、電荷発生層塗工液を以下のものに変更した以外は、感光体１１と同様に感光体を作製した。
【０１６６】
◎電荷発生層塗工液
先に合成したチタニルフタロシアニンＣ １５部
ポリビニルブチラール １０部
２−ブタノン ２８０部
【０１６７】
＜黒色トナー現像剤Ｋ−１の作製＞
（黒色トナー）
ポリエステル樹脂 ９５部
カルナウバワックス ５部
カーボンブラック １０部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。
【０１６８】
また、湿式法により作製したマグネタイト１００重量部に対してポリビニルアルコール２重量部、水６０重量部をボールミルに入れ１２時間混合してマグネタイトのスラリーを調整した。このスラリーをスプレードライヤーにて噴霧造粒し、球形粒子とした。この粒子を窒素雰囲気中で１０００℃の温度で３時間焼成後冷却し、核体粒子１を得た。
シリコーン樹脂溶液 １００部
トルエン １００部
γ−アミノプロピルトリメトキシシラン １５部
カーボンブラック ２０部
【０１６９】
上記混合物をホモミキサーで２０分間分散し、被覆層形成液１を調整した。この被覆層形成液１を、流動床型コーティング装置を用いて核体粒子１を１０００部の表面にコーティングして、シリコーン樹脂被覆キャリアＡ（磁性キャリアＡ）を得た。
上記磁性キャリアＡを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤（Ｋ−１）を作製した。
【０１７０】
＜イエロートナー現像剤Ｙ−１の作製＞
（イエロートナー）
ポリエステル樹脂 ９５部
カルナウバワックス ５部
Ｃ．Ｉ．ピグメントイエロー１８０ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。このトナー２．５部を、先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｙ−１）を作製した。
【０１７１】
＜マゼンタトナー現像剤Ｍ−１の作製＞
（マゼンタトナー）
ポリエステル樹脂 ９５部
カルナウバワックス ５部
Ｃ．Ｉ．ピグメントレッド５７：１ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。このトナー２．５部を、先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｍ−１）を作製した。
【０１７２】
＜シアントナー現像剤Ｃ−１の作製＞
（シアントナー）
ポリエステル樹脂 ９５部
カルナウバワックス ５部
Ｃ．Ｉ．ピグメントブルー１５：３ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。このトナー２．５部を、先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｃ−１）を作製した。
【０１７３】
＜透明トナー現像剤Ｔ−１の作製＞
（透明トナー）
ポリエステル樹脂 ９５部
カルナウバワックス ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。このトナー２．５部を、先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｔ−１）を作製した。
【０１７４】
＜白色トナー現像剤Ｗ−１の作製＞
（白色トナー）
ポリエステル樹脂 ９５部
カルナウバワックス ５部
酸化チタン ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。このトナー２．５部を、先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｗ−１）を作製した。
【０１７５】
＜黒色トナー現像剤Ｋ−２の作製＞
（黒色トナー）
ポリエステル樹脂 １００部
カーボンブラック １０部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．０μｍのトナーを得た。上記トナーに、酸化チタン微粒子１ｗｔ％、シリカ微粒子１ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｋ−２）を作製した。
【０１７６】
＜イエロートナー現像剤Ｙ−２の作製＞
（イエロートナー）
ポリエステル樹脂 １００部
Ｃ．Ｉ．ピグメントイエロー１８０ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．０μｍのトナーを得た。上記トナーに、酸化チタン微粒子１ｗｔ％、シリカ微粒子１ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｙ−２）を作製した。
【０１７７】
＜マゼンタトナー現像剤Ｍ−２の作製＞
（マゼンタトナー）
ポリエステル樹脂 １００部
Ｃ．Ｉ．ピグメントレッド５７：１ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．０μｍのトナーを得た。上記トナーに、酸化チタン微粒子１ｗｔ％、シリカ微粒子１ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｍ−２）を作製した。
【０１７８】
＜シアントナー現像剤Ｃ−２の作製＞
（シアントナー）
ポリエステル樹脂 １００部
Ｃ．Ｉ．ピグメントブルー１５：３ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．０μｍのトナーを得た。上記トナーに、酸化チタン微粒子１ｗｔ％、シリカ微粒子１ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｃ−２）を作製した。
【０１７９】
＜透明トナー現像剤Ｔ−２の作製＞
（透明トナー）
ポリエステル樹脂 １００部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．０μｍのトナーを得た。上記トナーに、酸化チタン微粒子１ｗｔ％、シリカ微粒子１ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｔ−２）を作製した。
【０１８０】
＜白色トナー現像剤Ｗ−２の作製＞
（白色トナー）
ポリエステル樹脂 １００部
酸化チタン ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．０μｍのトナーを得た。上記トナーに、酸化チタン微粒子１ｗｔ％、シリカ微粒子１ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｗ−２）を作製した。
【０１８１】
＜黒色トナー現像剤Ｋ−３の作製＞
（黒色トナー）
ポリエステル樹脂 １００部
カーボンブラック １０部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．５μｍのトナーを得た。上記トナーに、酸化チタン微粒子０．９ｗｔ％、シリカ微粒子０．９ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｋ−３）を作製した。
【０１８２】
＜イエロートナー現像剤Ｙ−３の作製＞
（イエロートナー）
ポリエステル樹脂 １００部
Ｃ．Ｉ．ピグメントイエロー１８０ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．５μｍのトナーを得た。上記トナーに、酸化チタン微粒子０．９ｗｔ％、シリカ微粒子０．９ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｙ−３）を作製した。
【０１８３】
＜マゼンタトナー現像剤Ｍ−３の作製＞
（マゼンタトナー）
ポリエステル樹脂 １００部
Ｃ．Ｉ．ピグメントレッド５７：１ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．５μｍのトナーを得た。上記トナーに、酸化チタン微粒子０．９ｗｔ％、シリカ微粒子０．９ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｍ−３）を作製した。
【０１８４】
＜シアントナー現像剤Ｃ−３の作製＞
（シアントナー）
ポリエステル樹脂 １００部
Ｃ．Ｉ．ピグメントブルー１５：３ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．５μｍのトナーを得た。上記トナーに、酸化チタン微粒子０．９ｗｔ％、シリカ微粒子０．９ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｃ−３）を作製した。
【０１８５】
＜透明トナー現像剤Ｔ−３の作製＞
（透明トナー）
ポリエステル樹脂 １００部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．５μｍのトナーを得た。上記トナーに、酸化チタン微粒子０．９ｗｔ％、シリカ微粒子０．９ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｔ−３）を作製した。
【０１８６】
＜白色トナー現像剤Ｗ−３の作製＞
（シアントナー）
ポリエステル樹脂 １００部
酸化チタン ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径７．５μｍのトナーを得た。上記トナーに、酸化チタン微粒子０．９ｗｔ％、シリカ微粒子０．９ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。このトナー２．５部を先の磁性キャリアＡ９７．５部と混合して２成分現像剤（Ｗ−３）を作製した。
【０１８７】
＜黒色トナー現像剤Ｋ−４の作製＞
（黒色トナー）
ポリエステル樹脂 １００部
カーボンブラック １０部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。
上記トナーに、シリカ微粒子１．５ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。上記磁性キャリアＡを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤（Ｋ−４）を作製した。
【０１８８】
＜イエロートナー現像剤Ｙ−４の作製＞
（イエロートナー）
ポリエステル樹脂 ９５部
Ｃ．Ｉ．ピグメントイエロー１８０ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。上記トナーに、シリカ微粒子１．５ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。上記磁性キャリアＡを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤（Ｙ−４）を作製した。
【０１８９】
＜マゼンタトナー現像剤Ｍ−４の作製＞
（マゼンタトナー）
ポリエステル樹脂 ９５部
Ｃ．Ｉ．ピグメントレッド５７：１ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。
上記トナーに、シリカ微粒子１．５ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。上記磁性キャリアＡを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤（Ｍ−４）を作製した。
【０１９０】
＜シアントナー現像剤Ｃ−４の作製＞
（シアントナー）
ポリエステル樹脂 ９５部
Ｃ．Ｉ．ピグメントブルー１５：３ ５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。
上記トナーに、シリカ微粒子１．５ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。上記磁性キャリアＡを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤（Ｃ−４）を作製した。
【０１９１】
＜透明トナー現像剤Ｔ−４の作製＞
（透明トナー）
ポリエステル樹脂 ９５部
サリチル酸誘導体亜鉛塩 ２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。
上記トナーに、シリカ微粒子１．５ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。上記磁性キャリアＡを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤（Ｔ−４）を作製した。
【０１９２】
＜白色トナー現像剤Ｗ−４の作製＞
（白色トナー）
ポリエステル樹脂 ９５部
酸化チタン ５部
４級アンモニウム系帯電制御剤（保土ヶ谷化学製、「ＴＰ−４１５」）
２部
上記組成の混合物を、溶融混練し、その後粉砕、分級し、平均粒径８．０μｍのトナーを得た。
また、湿式法により作製したマグネタイト１００重量部に対してポリビニルアルコール２重量部、水６０重量部をボールミルに入れ１２時間混合してマグネタイトのスラリーを調整した。このスラリーをスプレードライヤーにて噴霧造粒し、球形粒子とした。この粒子を窒素雰囲気中で１０００℃の温度で３時間焼成後冷却し、核体粒子を得た。
シリコーン樹脂溶液 １００部
トルエン １００部
カーボンブラック ２０部
上記混合物をホモミキサーで２０分間分散し、被覆層形成液２を調整した。この被覆層形成液２を、流動床型コーティング装置を用いて核体粒子１を１０００部の表面にコーティングして、シリコーン樹脂被覆キャリアＢ（磁性キャリアＢ）を得た。
上記トナーに、シリカ微粒子１．５ｗｔ％、ステアリン酸亜鉛０．２ｗｔ％（いずれもトナーに対して）を外添した。上記磁性キャリアＢを９７．５部に対し、トナー２．５部の割合で混合し、二成分現像剤 （Ｗ−４）を作製した。現像剤Ｗ−４は、正帯電用の現像剤である。
【０１９３】
＜実施例１＞
図７（ａ）に示すカートリッジに感光体１をセットし、３つの画像形成要素（Ｍ、Ｃ、Ｋ）を用意した。また、図７−ｂに示すカートリッジに感光体１をセットし、１つの画像形成要素（Ｙ）を用意した。これら画像形成要素カートリッジを図２に示す画像形成装置に搭載した。それぞれの画像形成要素の有色トナー用現像部に、Ｋ−１，Ｙ−１，Ｍ−１，Ｃ−１の現像剤を投入し、全ての透明トナー現像部にＴ−１の現像剤を投入した。更に画像形成要素（Ｙ）に搭載された白色トナー現像部に、Ｗ−１の現像剤を投入した（いずれもトナーが負帯電され、画像光書き込み部に反転現像される）。帯電部材としては、図６に示すような非接触帯電ローラ（画像形成領域におけるローラ表面と感光体表面の空隙は５０μｍ）を用い、感光体未露光部の表面電位が−６００ＶになるようにＡＣを重畳した帯電を行った（ＤＣバイアス：−６００Ｖ、ＡＣバイアス：２．０ｋＶ（ｐｅａｋ ｔｏ ｐｅａｋ）、周波数：１．２ｋＨｚ）。有色トナー画像形成用の露光光源（第１の書き込み光）として、６５５ｎｍのＬＤ（感光体表面でのビーム径５０μｍ）を用い、６００ｄｐｉの書き込み密度で書き込みを行った（ベタ部での照射エネルギーは４．０ｅｒｇ）。Ｍ，Ｃ、Ｋの画像形成要素においては、第２の露光光源として６７０ｎｍＬＥＤを用い、有色トナー現像を行った後、各々の感光体全面に光照射を行ない、透明トナーの現像を行った。Ｙの画像形成要素においては、第２の露光光源として６５５ｎｍＬＤを用い、有色トナー現像を行った後、Ｍ，Ｃ、Ｋの有色トナーの現像を行った部分にのみ書き込みを行い、透明トナーを現像し、更に第３の露光用光源として６７０ｎｍＬＥＤを用い、感光体全面に光照射を行い白色トナーを現像した。いずれの現像も非接触方式の現像を行った。転写用帯電部材としてはスコロトロンチャージャーを用い、転写電流が３５μＡになるように制御した。クリーニング部材としてはウレタンゴム製のブレードを用いた。
【０１９４】
以上の条件にて、図１２に示すＡ４原稿を、用紙の長手方向と感光体長手方向を揃えた向きにて、１０００００枚の画像出力を行った。５枚目および１０００００枚後の画像を評価した。また、１０００００枚出力後に、Ｙ，Ｍ，Ｃ，Ｋ、各々単独のハーフトーン画像を１枚ずつ、白ベタ画像を出力した。以上の画像評価は全てＡ４用紙（感光体長手方向と用紙長手方向を揃えて）に出力を行った。更に、カートリッジより感光体を取り出し、感光体長手方向の膜厚分布を測定した。以上の結果を表１に示す。
【０１９５】
＜実施例２＞
実施例１の実験において、有色トナー現像剤、透明トナー現像剤、および白色トナー現像剤としてとして、Ｋ−２，Ｙ−２，Ｍ−２，Ｃ−２、Ｔ−２及びＷ−２を用いた以外は、実施例１と同様に評価を行った。結果を表１に示す。
【０１９６】
＜実施例３＞
実施例１の実験において、有色トナー現像剤及び透明トナー現像剤および白色トナー現像剤としてとして、Ｋ−３，Ｙ−３，Ｍ−３，Ｃ−３、Ｔ−２及びＷ−２を用いた以外は、実施例１と同様に評価を行った。結果を表１に示す。
【０１９７】
＜比較例１＞
実施例１の実験において、第２の露光部材、透明トナー現像部材、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例１と同様に評価を行った。結果を表１に示す。
【０１９８】
＜比較例２＞
実施例２の実験において、第２の露光部材、透明トナー現像部材、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２と同様に評価を行った。結果を表１に示す。
【０１９９】
＜比較例３＞
実施例３の実験において、第２の露光部材、透明トナー現像部材、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２００】
＜比較例４＞
実施例１の実験において、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例１と同様に評価を行った。結果を表１に示す。
【０２０１】
＜比較例５＞
実施例２の実験において、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２と同様に評価を行った。結果を表１に示す。
【０２０２】
＜比較例６＞
実施例３の実験において、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０３】
＜比較例７＞
実施例３の実験において、全ての画像形成要素カートリッジに搭載した感光体を感光体２に変更した以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０４】
＜比較例８＞
実施例３の実験において、全ての画像形成要素カートリッジに搭載した感光体を感光体３に変更した以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０５】
＜比較例９＞
実施例３の実験において、全ての画像形成要素カートリッジに搭載した感光体を感光体４に変更した以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０６】
＜実施例４＞
実施例３の実験において、第３の露光部材を６５５ｎｍＬＤとし、白色トナー画像形成部（全ての有色トナー非画像形成部）にのみ書き込みを行った以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０７】
＜実施例５＞
実施例３の実験において、全ての画像形成要素に搭載された第２の露光部材を６５５ｎｍＬＤとして、透明トナー画像形成部にのみ書き込みを行った以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０８】
＜実施例６＞
実施例３の実験において、有色トナー現像剤、透明トナー現像剤及び白色トナー現像剤として、Ｋ−４，Ｙ−４，Ｍ−４，Ｃ−４、Ｔ−４及びＷ−４を用い、画像形成要素（Ｙ）から第３の露光部材を取り外し（図１および図７（ｃ）の構成）、白色トナーを正規現像にて現像を行った以外は、実施例３と同様に評価を行った。結果を表１に示す。
【０２０９】
＜実施例７＞
実施例５の実験において、Ａ４用紙の長手方向を感光体長手方向に対して直角に出力した。この際、第２の露光部材として６７０ｎｍＬＥＤを用い、有色トナー現像を行った後、各々の感光体全面に光照射を行った（用紙が当接しない部分には透明トナーが現像される。画像形成要素（Ｋ）においては、白色トナーは現像されない）。結果を表１に示す。
【０２１０】
＜実施例８＞
実施例７の実験において、第２の露光部材として６５５ｎｍＬＤとして、用紙幅の有色トナー非現像部のみに書き込みを行い、画像出力した以外は実施例６と同様に評価を行った（用紙の当接しない感光体表面には書き込みは行っていない。いずれの画像形成要素においても用紙が当接しない部分には、透明トナー及び白色トナーは現像されない）。結果を表１に示す。
【０２１１】
＜実施例９＞
実施例５の実験において、原稿サイズをＡ４からＢ５に変更し（画像は８７％に縮小し、図１２と同じ画像をＢ５に納めた）、用紙の長手方向を感光体の長手方向に揃えて出力を行った。この際、第２の露光部材として６７０ｎｍＬＥＤを用い、有色トナー現像を行った後、各々の感光体全面に光照射を行った（用紙が当接しない部分には透明トナーが現像される。画像形成要素（Ｋ）においては、白色トナーは現像されない）。結果を表１に示す。
【０２１２】
＜実施例１０＞
実施例８の実験において、第２の露光部材として６５５ｎｍＬＤとして、用紙幅の有色トナー非現像部のみに書き込みを行い、画像出力した以外は実施例８と同様に評価を行った（用紙の当接しない感光体表面には書き込みは行っていない。いずれの画像形成要素においても用紙が当接しない部分には、透明トナー及び白色トナーは現像されない）。結果を表１に示す。
【０２１３】
＜実施例１１＞
実施例５の実験において、全ての画像形成要素カートリッジに搭載した感光体を、感光体５に変更した以外は、実施例５と同様に評価を行った。結果を表１に示す。
【０２１４】
＜実施例１２＞
実施例５の実験において、全ての画像形成要素カートリッジに搭載した感光体を、感光体６に変更した以外は、実施例５と同様に評価を行った。結果を表１に示す。
【０２１５】
＜実施例１３＞
実施例５の実験において、全ての画像形成要素カートリッジに搭載した感光体を、感光体７に変更した以外は、実施例５と同様に評価を行った。結果を表１に示す。
【０２１６】
＜実施例１４＞
実施例５の実験において、全ての画像形成要素カートリッジに搭載した感光体を、感光体８に変更した以外は、実施例５と同様に評価を行った。結果を表１に示す。
【０２１７】
＜実施例１５＞
実施例５の実験において、全ての画像形成要素カートリッジに搭載した感光体を、感光体９に変更した以外は、実施例５と同様に評価を行った。結果を表１に示す。
【０２１８】
＜実施例１６＞
実施例５の実験において、全ての画像形成要素カートリッジに搭載した感光体を、感光体１０に変更した以外は、実施例５と同様に評価を行った。結果を表１に示す。
【０２１９】
＜実施例１７＞
実施例５の実験において、非接触帯電ローラのギャップを１５０μｍに変更した以外は、実施例５と同様に実験を行った。結果を表１に示す。
【０２２０】
＜実施例１８＞
実施例５の実験において、非接触帯電ローラのギャップを２５０μｍに変更した以外は、実施例５と同様に実験を行った。結果を表１に示す。
【０２２１】
＜実施例１９＞
実施例５の実験において、帯電ローラのギャップを０μｍ（接触状態にした）に変更した以外は、実施例５と同様に実験を行った。結果を表１に示す。
【０２２２】
＜比較例１０＞
実施例１９の実験において、帯電ローラの帯電条件を下記の通り変更した以外は、実施例１９と同様に実験を行った。結果を表１に示す。
帯電条件：
ＡＣバイアス：なし
ＤＣバイアス：−１５００Ｖ（感光体の未露光部表面電位が、−６００Ｖになるように調整）
【０２２３】
＜比較例１１＞
実施例５の実験において、帯電ローラをスコロトロンチャージャーに変更し、以下の帯電条件に変更した以外は、実施例５と同様に実験を行った。結果を表１に示す。
帯電条件：
印加電圧：−６．２ｋＶ
グリッド電位： −６００Ｖ
表１中の白ベタ画像は、地肌部の汚れ（地汚れ）を下記の基準に従って評価を行った。
【０２２４】
＜地汚れランク＞
５：地汚れほとんどなし、４：わずかにあり、
３：実使用限界レベル、２以下：実使用には耐えないレベル
表１中の膜厚とは、感光体１００００回転あたりの摩耗量を表す（代表例として、マゼンタステーションで使用した感光体の値を示す）。実施例で使用した感光体においては、感光体の長手方向１０ｍｍおきに測定し、算術平均を求めた。一方、比較例で使用した感光体は、部分的に摩耗を生じている領域があるため、部分的に摩耗している部分を除き、ほぼ均一に摩耗している部分（感光体中央部）の算術平均を求めた。
膜厚均一性とは、長手方向の膜厚プロフィールを示すものであり、ランニング試験によりどの様にプロフィールが変化したか均一摩耗部に対して比較して示したものである。４本の感光体で状況が異なる場合は、感光体ごとにその特徴を示す。
【０２２５】
【表１】

【０２２６】
【表２】

【０２２７】
＜実施例２０＞
図７−ａに示すカートリッジに感光体１１をセットし、３つの画像形成要素（Ｍ、Ｃ、Ｋ）を用意した。また、図７（ｂ）に示すカートリッジに感光体１をセットし、１つの画像形成要素（Ｙ）を用意した。これら画像形成要素カートリッジを図２に示す画像形成装置に搭載した。それぞれの画像形成要素の有色トナー用現像部に、Ｋ−１，Ｙ−１，Ｍ−１，Ｃ−１の現像剤を投入し、全ての透明トナー現像部にＴ−１の現像剤を投入した。更に画像形成要素（Ｙ）に搭載された白色トナー現像部に、Ｗ−１の現像剤を投入した（いずれもトナーが負帯電され、画像光書き込み部に反転現像される）。帯電部材としては、図６に示すような非接触帯電ローラ（画像形成領域におけるローラ表面と感光体表面の空隙は５０μｍ）を用い、感光体未露光部の表面電位が−６００ＶになるようにＡＣを重畳した帯電を行った（ＤＣバイアス：−６００Ｖ、ＡＣバイアス：２．０ｋＶ（ｐｅａｋ ｔｏ ｐｅａｋ）、周波数：１．２ｋＨｚ）。有色トナー画像形成用の露光光源（第１の書き込み光）として、７８０ｎｍのＬＤ（感光体表面でのビーム径５０μｍ）を用い、６００ｄｐｉの書き込み密度で書き込みを行った（ベタ部での照射エネルギーは４．０ｅｒｇ）。Ｍ，Ｃ、Ｋの画像形成要素においては、第２の露光光源として６７０ｎｍＬＥＤを用い、有色トナー現像を行った後、各々の感光体全面に光照射を行ない、透明トナーの現像を行った。Ｙの画像形成要素においては、第２の露光光源として７８０ｎｍＬＤを用い、有色トナー現像を行った後、Ｍ，Ｃ、Ｋの有色トナーの現像を行った部分にのみ書き込みを行い、透明トナーを現像し、更に第３の露光用光源として６７０ｎｍＬＥＤを用い、感光体全面に光照射を行い白色トナーを現像した。いずれの現像も非接触方式の現像を行った。転写用帯電部材としてはスコロトロンチャージャーを用い、転写電流が３５μＡになるように制御した。クリーニング部材としてはウレタンゴム製のブレードを用いた。
【０２２８】
以上の条件にて、図１２に示すＡ４原稿を、用紙の長手方向と感光体長手方向を揃えた向きにて、１０００００枚の画像出力を行った。５枚目および１０００００枚後の画像を評価した。また、１０００００枚出力後に、Ｙ，Ｍ，Ｃ，Ｋ、各々単独のハーフトーン画像を１枚ずつ、白ベタ画像を出力した。以上の画像評価は全てＡ４用紙（感光体長手方向と用紙長手方向を揃えて）に出力を行った。更に、カートリッジより感光体を取り出し、感光体長手方向の膜厚分布を測定した。以上の結果を表２に示す。
【０２２９】
＜実施例２１＞
実施例２０の実験において、有色トナー現像剤、透明トナー現像剤、および白色トナー現像剤としてとして、Ｋ−２，Ｙ−２，Ｍ−２，Ｃ−２、Ｔ−２及びＷ−２を用いた以外は、実施例２０と同様に評価を行った。結果を表２に示す。
【０２３０】
＜実施例２２＞
実施例２０の実験において、有色トナー現像剤及び透明トナー現像剤および白色トナー現像剤としてとして、Ｋ−３，Ｙ−３，Ｍ−３，Ｃ−３、Ｔ−２及びＷ−３を用いた以外は、実施例２０と同様に評価を行った。結果を表２に示す。
【０２３１】
＜比較例１２＞
実施例２０の実験において、第２の露光部材、透明トナー現像部材、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２０と同様に評価を行った。結果を表２に示す。
【０２３２】
＜比較例１３＞
実施例２１の実験において、第２の露光部材、透明トナー現像部材、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２１と同様に評価を行った。結果を表２に示す。
【０２３３】
＜比較例１４＞
実施例２２の実験において、第２の露光部材、透明トナー現像部材、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２２と同様に評価を行った。結果を表２に示す。
【０２３４】
＜比較例１５＞
実施例２０の実験において、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２０と同様に評価を行った。結果を表２に示す。
【０２３５】
＜比較例１６＞
実施例２１の実験において、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２１と同様に評価を行った。結果を表２に示す。
【０２３６】
＜比較例７＞
実施例２２の実験において、第３の露光部材、白色トナー現像部材を画像形成装置から取り外し、画像形成を行った以外は、実施例２２と同様に評価を行った。結果を表２に示す。
【０２３７】
＜実施例２３＞
実施例２２の実験において、全ての画像形成要素に搭載された第２の露光部材を７８０ｎｍＬＤとして、透明トナー画像形成部にのみ書き込みを行った以外は、実施例２２と同様に評価を行った。結果を表２に示す。
【０２３８】
＜実施例２４＞
実施例２２の実験において、有色トナー現像剤、透明トナー現像剤及び白色トナー現像剤として、Ｋ−４，Ｙ−４，Ｍ−４，Ｃ−４、Ｔ−４及びＷ−４を用い、画像形成要素（Ｋ）から第３の露光部材を取り外し（図１および図７−ｃの構成）、白色トナーを正規現像にて現像を行った以外は、実施例２２と同様に評価を行った。結果を表２に示す。
【０２３９】
＜実施例２５＞
実施例２３の実験において、全ての画像形成要素カートリッジに搭載した感光体を感光体１２に変更した以外は、実施例２３と同様に評価を行った。結果を表２に示す。
【０２４０】
＜実施例２６＞
実施例２３の実験において、全ての画像形成要素カートリッジに搭載した感光体を感光体１３に変更した以外は、実施例２３と同様に評価を行った。結果を表２に示す。
【０２４１】
＜実施例２７＞
実施例２３の実験において、全ての画像形成要素カートリッジに搭載した感光体を感光体１４に変更した以外は、実施例２３と同様に評価を行った。結果を表２に示す。
表２中の白ベタ画像は、地肌部の汚れ（地汚れ）を下記の基準に従って評価を行った。
【０２４２】
＜地汚れランク＞
５：地汚れほとんどなし、４：わずかにあり、
３：実使用限界レベル、２以下：実使用には耐えないレベル
表２中の膜厚とは、感光体１００００回転あたりの摩耗量を表す（代表例として、マゼンタステーションで使用した感光体の値を示す）。実施例で使用した感光体においては、感光体の長手方向１０ｍｍおきに測定し、算術平均を求めた。一方、比較例で使用した感光体は、部分的に摩耗を生じている領域があるため、部分的に摩耗している部分を除き、ほぼ均一に摩耗している部分（感光体中央部）の算術平均を求めた。
【０２４３】
表２中の膜厚均一性とは、長手方向の膜厚プロフィールを示すものであり、ランニング試験によりどの様にプロフィールが変化したか均一摩耗部に対して比較して示したものである。４本の感光体で状況が異なる場合は、感光体ごとにその特徴を示す。
【０２４４】
【表３】

【０２４５】
【発明の効果】
以上、詳細且つ具体的な説明から明らかなように、本発明によれば、多種多様な原稿の出力に際しても、感光体の部分的な劣化を防止し、高耐久で繰り返し使用に対し色再現性が良好で地汚れの目立たない安定な画像を形成可能で、かつ高速フルカラー用電子写真装置が提供される。
【図面の簡単な説明】
【図１】本発明のフルカラー画像形成装置を説明するための概略図である。
【図２】本発明のフルカラー画像形成装置の別の構成例を示す断面図である。
【図３】感光体に対する転写紙の給紙方向を表す図である。
【図４】感光体と転写紙の長手方向の関係を表す図である。
【図５】転写紙上の転写されたトナー層の状態を表す図である。
【図６】近接帯電機構を表す概略図である（ギャップ形成部材が帯電部材側についている）。
【図７】プロセスカートリッジの一例を表す概略図である。
（ａ）は、白色トナー現像部材を有さない画像形成要素プロセスカートリッジ
（ｂ）は、白色トナー現像部材を有する画像形成要素プロセスカートリッジ
（白色トナー現像に書き込みを使用する場合）
（ｃ）は、白色トナー現像部材を有する画像形成要素プロセスカートリッジ
（白色トナー現像に書き込みを使用しない場合）
【図８】本発明の電子写真感光体を表わす断面図である。
【図９】チタニルフタロシアニンＡのＸ線回折スペクトルである。
【図１０】チタニルフタロシアニンＢのＸ線回折スペクトルである。
【図１１】チタニルフタロシアニンＣのＸ線回折スペクトルである。
【図１２】実施例で用いた原稿を表す図である。
【符号の説明】
１Ｃ、１Ｍ、１Ｙ、１Ｋ ・・・・ 感光体
２Ｃ、２Ｍ、２Ｙ、２Ｋ ・・・・ 帯電部材
３Ｃ、３Ｍ、３Ｙ、３Ｋ ・・・・ レーザ光
４Ｃ、４Ｍ、４Ｙ、４Ｋ ・・・・ 有色トナー用現像部材
５Ｃ、５Ｍ、５Ｙ、５Ｋ ・・・・ 透明トナー用現像部材
６Ｃ、６Ｍ、６Ｙ、６Ｋ ・・・・ クリーニング部材
７Ｃ、７Ｍ、７Ｙ、７Ｋ ・・・・ 転写用帯電部材
８ ・・・・ 中間転写ベルト
９ ・・・・ レジストローラ
１０ ・・・ 定着装置
１１Ｃ、１１Ｍ、１１Ｙ、１１Ｋ ・・・・ 画像形成要素
１２ ・・・ 転写紙
１３Ｙ ・・・ 白色トナー現像部材
１４Ｃ、１４Ｍ、１４Ｙ、１４Ｋ ・・・・ 第２の露光部材
１５Ｙ ・・・ 第３の露光部材
１６ ・・・ 転写搬送部材
１７ ・・・ 転写搬送部材の駆動もしくは従動ローラ
１０１ ・・・ 感光体
１０２ ・・・ フランジ
１０３ ・・・ 転写紙
Ｋ ・・・ ブラックトナー
Ｃ ・・・ シアントナー
Ｍ ・・・ マゼンタトナー
Ｙ ・・・ イエロートナー
Ｔ ・・・ 透明トナー
Ｗ ・・・ 白色トナー
１ ・・・ 感光体
２ ・・・ 帯電部材
２１ ・・・ ギャップ形成部材
２２ ・・・ 金属シャフト
２３ ・・・ 画像形成領域
２４ ・・・ 非画像形成領域
２０１ ・・・ 感光体
２０２ ・・・ 帯電部材
２０３ ・・・ 有色トナー用書き込み部材
２０４ ・・・ 有色トナー用現像部材
２０５ ・・・ 第２の露光部材
２０６ ・・・ 透明トナー用現像部材
２０７ ・・・ クリーニング部材
２０８ ・・・ 白色トナー用現像部材
２０９ ・・・ 第３の露光部材
３１ ・・・ 導電性支持体
３５ ・・・ 電荷発生層
３７ ・・・ 電荷輸送層
３９ ・・・ 表面保護層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tandem electrophotographic image forming apparatus. Specifically, the present invention relates to a high-speed full-color image forming apparatus.
[0002]
[Prior art]
As a full-color image forming apparatus using an electrophotographic system, two systems are generally known. One is a so-called single system or single drum system, in which one electrophotographic photosensitive member is mounted in the apparatus and four color developing members are mounted. In this system, C (cyan), M (magenta), Y (on the photosensitive member or on the transfer target member (directly transferred to the output paper or once transferred to the intermediate transfer member and then transferred to the paper). Four color toner images of yellow and K (black) are formed. In this case, the charging member, the exposure member, the transfer member, the cleaning member, and the fixing member arranged around the photosensitive member can be shared, and are designed to be smaller and less expensive than the tandem method described later. Is possible.
[0003]
On the other hand, another system is called a tandem system or a tandem drum system. This is one in which a plurality of electrophotographic photosensitive members are mounted at least in the apparatus. In general, one charging, exposing, developing, and cleaning member is arranged for each drum to form one image forming element, and a plurality (generally four) of them are mounted. Has been. In this method, a single color toner image is formed by one electrophotographic element, and the toner image is sequentially transferred to a transfer target to form a full color image. The merit of this method is that high-speed image formation is possible. This is because the toner images of the respective colors can be produced by parallel processing as described above. For this reason, compared with the single method, the image forming processing time is about one-fourth, and it is possible to cope with four times higher speed printing. The second merit is that the durability of each member provided in the image forming element including the photoreceptor can be substantially increased. This is because, in the single method, each process of charging, exposure, and development is performed four times with one photoconductor to form one full color image, whereas in the tandem method, the above operation is performed once with one photoconductor. This is because they only do it.
[0004]
However, it also has the demerit that the entire device becomes large and the cost becomes high. As for the size of the entire apparatus, measures have been taken by reducing the diameter of the photosensitive member, reducing the size of each member installed around the photosensitive member, and reducing the size of one image forming element. As a result, the effect of reducing the material cost as well as the size of the device has been produced, and the cost of the entire device has been reduced somewhat. However, with the downsizing and downsizing of the apparatus, a new problem has arisen that the durability of each member including the photoconductor mounted on the image forming element has to be increased.
[0005]
For example, in order to reduce the size of a tandem type full-color device, a shift has been made from using a scorotron charger as a charging member to using a charging roller. When the charging roller is used, there is a case where the charging uniformity on the photosensitive member is inferior to the case where the scorotron charger is used. In the tandem full-color image forming apparatus, this non-uniform charging is a fatal problem, and in particular causes deterioration in color balance (color reproducibility). For this reason, an alternating electric field in which an AC component is superimposed on a DC component is applied during charging. Thereby, the charging uniformity is improved and a good image can be obtained. However, the superposition of alternating current components has a great influence on the repeated use of the photoreceptor. Specifically, the surface of the photoconductor is accelerated, and image blurring and toner filming are promoted. On the other hand, the use of the scorotron charger is difficult to implement due to problems such as the odor of ozone gas generated from the charger deteriorating the office environment. For this reason, a technique for making full use of a charging roller using an alternating electric field has been indispensable for a tandem full-color image forming apparatus.
[0006]
In this way, the speed of color machines has been increased and gradually used for business documents and the like, but at first, the ratio of monochrome and color originals was about half. For this reason, among the plurality of image forming elements mounted on the tandem type full color machine, the image forming element for developing the black toner is used about twice as much as the other image forming elements. For this reason, in particular, the durability of the image forming element for developing a black toner has to be substantially increased.
[0007]
In order to deal with such problems, the idea of using a photoconductor mounted on a black toner developing image forming element having higher durability than a photoconductor mounted on another image forming element has emerged. It was. For example, Japanese Patent Laid-Open No. 10-333393 proposes using an amorphous silicon photoconductor having a specific thickness or more as a photoconductor using a black toner image, and using OPC (organic photoconductor) for the other three colors. Has been made. Japanese Patent Application Laid-Open No. 11-52599 proposes to use a photoconductor having an a-SiC photoconductive layer having a specific thickness or more as a photoconductor using a black toner image. In addition, Japanese Patent Laid-Open No. 2001-330974 describes the use of a polymer charge transport material for the photosensitive layer of the black toner image photoreceptor, and Japanese Patent Laid-Open No. 2001-330975 discloses the most preferable black toner image photoreceptor. Although a protective layer is described as a surface layer, Japanese Patent Application Laid-Open No. 2001-330976 uses a black toner image photosensitive member whose photosensitive layer thickness is larger than that of other toner image photosensitive members. There is a description.
In either full-color printer or copier, the ratio of monochrome (black) printing is high in the output document, and the durability of the photoconductor that forms a black toner image is increased, so that the durability of the entire system is substantially increased. It is intended to increase. This way of thinking is extremely reasonable in terms of life design considering cost. However, when a plurality of image forming elements are used in one image forming apparatus and photoconductors having different photoconductive layers are installed, there arises a problem that desired coloration cannot be obtained due to a difference in characteristics between the photoconductors.
[0008]
In recent years, the use of color machines has been used as an original color machine, and a considerable proportion of originals have been filled with color images. In particular, in business documents and the like, an increasing number of manuscripts in which a logo mark is inserted at one corner of a manuscript or a part of a document such as a fixed format is fixed have been used. In such a case, the frequency of use of a specific part increases with respect to the longitudinal direction of the photoconductor, resulting in a situation different from other parts.
There are several different situations here:
[0009]
{Circle around (1)} In a photoreceptor that is not very durable against electrostatic fatigue, fatigue of a frequently used part is promoted.
{Circle around (2)} In a photoconductor that is not so high in wear resistance, wear of a frequently used part is promoted.
{Circle around (3)} Photoconductors with very high wear resistance cause phenomena such as sticking of paper dust, toner, etc. (so-called filming) to frequently used parts.
[0010]
Such a situation is not preferable in general, but in the case of a monochrome electrophotographic apparatus or a single-type image forming apparatus (one image forming element), it can be handled by the following means. It is.
In contrast to (1), a photoconductor with a small electrostatic fatigue is used.
For (2), use a photoconductor having high wear resistance.
Strengthen the cleaning method against (3).
[0011]
However, the tandem type full-color image forming apparatus is a very big problem in terms of color balance (color reproducibility) which is not a problem in a monochrome machine. In particular, when high durability of the photoconductor is considered, wear resistance is emphasized, and a photoconductor having wear resistance of 0.1 μm or less per 10,000 rotations of the photoconductor in image formation is used. Becomes a significant issue.
On the other hand, in the case of a photoconductor with low wear resistance, the amount of partial wear becomes large, and this causes another abnormal image, and the life of the photoconductor is shortened before a color balance problem occurs. It will be greeted and exchanged. Alternatively, the wear speed of the photoconductor surface is higher than the speed at which paper dust and toner components adhere (adhere) to the photoconductor surface, and a phenomenon such as filming does not occur (of course, the lifetime is short). For this reason, the problem like the highly abrasion-resistant photoconductor used in the present invention is not highlighted.
[0012]
Accordingly, the object of the present invention is to use a photoconductor having a very high wear resistance in a tandem type full-color image forming apparatus, and a problem specific to full-color image output in a highly durable image forming apparatus (partial fatigue of the photoconductor). Or uneven wear). Such a problem cannot be solved by the above-described known technology.
[0013]
Japanese Patent Application Laid-Open No. 2002-318461 and Japanese Patent Application Laid-Open No. 2002-341577 disclose techniques for preventing the occurrence of abnormal images due to such uneven photoconductor wear. In either case, expecting uneven wear of the photoconductor, use a material whose thickness is changed in the longitudinal direction of the photoconductor, or by changing the wear rate in the longitudinal direction by changing the distribution of the filler amount in the surface protective layer. This corresponds to the above problem. However, it is difficult to fully predict the uneven wear of the photoconductor, but rather, the adverse effect due to the change in the photoconductor characteristics in the longitudinal direction of the photoconductor is initially greater.
[0014]
Further, some techniques using transparent toner in a full-color image forming apparatus are disclosed. For example, in Japanese Patent Laid-Open No. 6-175461, four developing units and a developing unit that develops transparent toner are provided in a transfer unit that transfers an electrostatic latent image on a photosensitive member, and each non-developed portion of a colored toner is provided in each non-developing portion. A method for developing a transparent toner is described, and it is proposed to eliminate unevenness on the image surface by aligning the height of each color toner layer. However, this method is used in a single system, cannot respond to high-speed image output, and cannot cope with deterioration due to local use of the photoreceptor. Japanese Patent Laid-Open No. 7-5738 discloses an image forming apparatus in which five revolver-type developing devices are set in contact with one photosensitive member in order, and one of them is a transparent toner, thereby transferring the image. It has been proposed to eliminate the unevenness of the toner layer transferred onto the paper and prevent the occurrence of incompletely melted portions of the toner during fixing. However, this apparatus is also used in a single system, cannot respond to high-speed image output, and cannot cope with deterioration due to local use of the photoreceptor. Japanese Patent Laid-Open No. 10-123853 discloses a technique in which a transparent toner is transferred onto the entire surface of a tandem type image forming apparatus before transferring the colored toner onto the transfer member. It has been proposed to prevent image misregistration. However, in this apparatus, the development of colored toner on the photoreceptor is not different from the prior art, and it cannot cope with deterioration due to local use of the photoreceptor.
[0015]
Japanese Patent Laid-Open No. 2002-91165 discloses an image forming apparatus having two developing units for one photoconductor in a tandem full-color image forming apparatus. This technique provides an image having a good gradation by using two developing devices and using a toner having a high density of colored toner and a toner having a low density. However, the toner is not developed on the entire surface of the photoconductor, and cannot cope with deterioration due to local use of the photoconductor.
[0016]
On the other hand, in such a tandem full-color image forming apparatus, image processing is performed by digitally processing the full-color image information after color separation. At this time, LD or LED is used for writing image information on the photoconductor, but the potential of the portion where the photowriting is performed on the photoconductor is attenuated in consideration of the influence of the life of the light source and the photo fatigue of the photoconductor. Thus, negative / positive development in which toner is developed in this portion and an image is formed is employed.
[0017]
In this negative / positive development, the background portion of the output document corresponds to the unexposed portion (high potential portion) of the photosensitive member, and if there is any defect in the photosensitive layer, the potential is originally The background portion (white background) to be held may be attenuated in potential, and as a result, point defects (background stains, spots, etc.) that do not exist in the background portion of the input document may occur. This defect may be mistaken for a point in the drawing, a period in the English manuscript, a comma, or the like, and can be said to be a fatal defect as an image. Such a defect is a serious problem even in a system in which a single photoconductor is used. However, in a tandem full-color image forming apparatus, a plurality of photoconductors are used. There is a danger.
[0018]
Several image forming apparatuses using white toner have been disclosed so far. JP-A-2001-313797, JP-A-2001-341352, JP-A-2002-49205, and JP-A-2002-236396. Etc. Japanese Patent Application Laid-Open No. 2001-313797 describes that a blurring portion of an image portion is detected and white toner is developed on the image portion to eliminate blurring and to emphasize the edge effect. However, when the image forming apparatus is simply applied to a color image forming apparatus and applied to all image forming elements, there is a problem that an image located in a lower layer disappears when the toner layers are stacked. Further, it is not possible to cope with deterioration due to local use of the photoconductor and the effect of concealing background dirt, which are the effects of the present invention.
[0019]
Japanese Patent Application Laid-Open No. 2001-341352 describes that smoothing is performed by covering a jagged portion of a shaggy generated at an oblique edge of an image portion with white toner. However, when the image forming apparatus is simply applied to a color image forming apparatus and applied to all image forming elements, there is a problem that an image located in a lower layer disappears when the toner layers are stacked. Further, it is not possible to cope with deterioration and background concealment due to local use of the photoconductor, which is an effect of the present invention.
Japanese Patent Application Laid-Open No. 2002-49205 describes that white toner is developed at an image edge portion to make toner dust inconspicuous. However, when the image forming apparatus is simply applied to a color image forming apparatus and applied to all image forming elements, there is a problem that an image located in a lower layer disappears when the toner layers are stacked. Further, it cannot cope with the deterioration due to the local use of the photoreceptor, which is an effect of the present invention.
[0020]
Japanese Patent Application Laid-Open No. 2002-236396 describes that after full color image formation, white toner is developed on an uneven portion of an image and intermediate transfer is performed to eliminate the uneven portion and to conceal the color of the transfer paper. There is. However, it is not possible to cope with the deterioration due to the local use of the photosensitive member and the obscuration of the background, which are the effects of the present invention.
[0021]
[Patent Document 1]
JP 10-333393 A
[Patent Document 2]
Japanese Patent Laid-Open No. 11-52599
[Patent Document 3]
JP 2001-330974 A
[Patent Document 4]
JP 2001-330975 A
[Patent Document 5]
JP 2001-330976 A
[Patent Document 6]
JP 2002-318461 A
[Patent Document 7]
Japanese Patent Laid-Open No. 2002-341577
[Patent Document 8]
JP-A-6-175461
[Patent Document 9]
Japanese Unexamined Patent Publication No. 7-5738
[Patent Document 10]
Japanese Patent Laid-Open No. 10-123853
[Patent Document 11]
JP 2002-911165 A
[Patent Document 12]
JP 2001-313797 A
[Patent Document 13]
JP 2001-341352 A
[Patent Document 14]
JP 2002-49205 A
[Patent Document 15]
JP 2002-236396 A
[Patent Document 16]
JP 2002-148904 A
[Patent Document 17]
JP 2002-148905 A
[Patent Document 18]
JP-A-5-94049 (see FIG. 1)
[Patent Document 19]
JP-A-5-113688 (see FIG. 1)
[Patent Document 20]
JP-A-3-109406
[Patent Document 21]
JP 2000-206723 A
[Patent Document 22]
JP 2001-340001 A
[0022]
[Problems to be solved by the invention]
It is an object of the present invention to prevent partial deterioration of a photoreceptor even when outputting any document, and to form a stable image with high durability and good color reproducibility for repeated use, and a high-speed full-color electrophotographic apparatus. Is to provide.
[0023]
[Means for Solving the Problems]
As a result of repeated studies based on the results obtained in the past, it has been found that the following conditions are indispensable in order to satisfy at least high-speed full-color compatibility and high durability.
That is, (1) using a tandem type image forming apparatus equipped with a plurality of image forming elements, and (2) photosensitivity that determines the life of the image forming elements in order to make the plurality of image forming elements highly durable. In order to improve the durability of the photoconductor, and (3) to achieve high durability of the photoconductor, it is possible to increase the electrostatic durability and improve the wear resistance of the photoconductor.
[0024]
Although such an image forming apparatus already exists, as described above, the usage method of the full-color image forming apparatus has become complicated, and a usage method that is unthinkable in the past has been performed by the user. First, there have been cases where it is impossible to cope with the simple high durability as described above. As a simple example, it is frequently used locally in the longitudinal direction of the photoconductor, and as a result, a part of the photoconductor deteriorates and an abnormal image is generated on a part of the image by repeated use. An example is given.
Therefore, the photoconductors mounted on the plurality of image forming elements are all photoconductors having high wear resistance such that the wear amount per 10,000 rotations of the photoconductor in image formation is 0.1 μm or less. However, no matter what image formation is performed, it is necessary to provide an image forming apparatus having a configuration in which the same usage is performed on the entire surface of all the photosensitive members.
[0025]
Based on the above design guidelines, as a result of examining the configuration of the image forming elements used in the tandem type full-color image forming apparatus, each image forming element has a color toner image forming means and a transparent toner image forming means. A transparent toner image is formed on all areas (non-image forming areas) where colored toner images are not formed in each image formation, and image formation is always performed on the entire surface of the photoreceptor. Therefore, the entire surface of the photosensitive member is always used uniformly, and the entire surface of the photoreceptor is subjected to wear and electrostatic fatigue. Further, in the image forming element that first transfers the toner to the intermediate transfer member, the white toner is developed in all areas where the colored toner is not developed.
By satisfying the above-described constituent requirements, it has been found that a highly durable and highly stable tandem type image forming apparatus can be designed, and the present invention has been completed.
[0026]
  Accordingly, the above-mentioned problem is (1) “charging means for charging a photosensitive member by applying a voltage in which an alternating current component is superimposed on a direct current component to at least a charging member, an image exposure means, a developing means, and a transfer. A full color in which a plurality of image forming elements are arranged, each comprising an electrophotographic photosensitive member provided with a surface protective layer having a wear resistance of 0.1 μm or less per 10,000 revolutions of the photosensitive member in image formation An image forming apparatus, a color toner developing unit that performs development based on the image exposure between an image exposure unit and a transfer unit used for forming a color toner image in each image forming element, and non-image formation of the color toner Image forming is performed by providing a developing means for developing the area with transparent toner, and further transferring toner to the intermediate transfer member first among a plurality of image forming elements A full-color image forming apparatus having a developing means for developing white toner between the colored toner developing means and the transferring means in the element; and (2) “colored toner developing means in the image forming element and transparent The full-color image according to item (1), wherein a second image exposure unit is provided between the toner development unit, the image exposure is performed on the non-image forming area of the colored toner, and the transparent toner is developed. Forming apparatus ", (3)" Full color image according to item (2) above, wherein at least the second image exposure means writes an electrostatic latent image on the photosensitive member with an LD or an LED. " Forming apparatus ", (4)" the full-color image forming apparatus according to any one of (1) to (3) above, wherein the development of the transparent toner is performed in a non-contact state ", ( 5) “In the image forming element having the white toner developing means, the white toner is developed in the non-image forming region of the colored toner in all the image forming elements,” in the above (1) to (4) Any one of the full-color image forming apparatus ”, (6)“ a third image exposing unit is provided between the colored toner developing unit and the white toner developing unit in the image forming element having the white toner developing unit; In the full color image forming apparatus according to (5) above, the entire surface of the photoconductor is irradiated with light and then developed with white toner.A third image exposure unit is provided between the color toner development unit and the white toner development unit in the image forming element having the white toner development unit;This is solved by the full-color image forming apparatus according to item (5), wherein the writing by the third image exposure means is performed only on the portions where the colored toner image and the transparent toner image are not exposed.
[0027]
Further, (8) “At least the third image exposure means writes an electrostatic latent image on the photosensitive member by using an LD or an LED, any one of the above items (6) to (7)” (9) "The charging polarity of the white toner is opposite to the charging polarity of the colored toner and the transparent toner". (1) to (5) 10. The full-color image forming apparatus according to any one of items 1 to 3, wherein the development of the white toner is performed in a non-contact state. (11) “The image exposure means used for the color toner image formation writes an electrostatic latent image on a photoconductor by means of an LD or an LED, Regardless of output The full-color image forming apparatus according to any one of (1) to (10), wherein the image is output with the longitudinal direction of the paper to be aligned with the longitudinal direction of the photoconductor ", (12)" In the image forming apparatus, the transparent toner is developed outside the range of the output paper even when the length of the output paper in the longitudinal direction is shorter than the length of the effective image forming area in the longitudinal direction of the photoreceptor. The full-color image forming apparatus according to the item (11) ”, (13)“ The charging means is a device in which a charging member is disposed in a non-contact proximity to a photosensitive member ”. Image forming apparatus according to any one of items (12), (14) “Image formation according to item (13), wherein the gap between the charging member and the photosensitive member is 200 μm or less. Apparatus ", (15)" for the imaging element " The colored toner, the transparent toner, and the white toner that are used contain waxes, and the contents of the waxes contained in both are substantially the same. The full-color image forming apparatus according to any one of items 1) and (16) “A color toner, a transparent toner and a white toner used in the image forming element each contain a lubricant, and the amount of lubricant contained in both of them is The full-color image forming apparatus according to any one of Items (1) to (14), which is substantially the same, (17) “The lubricant is zinc stearate” The full-color image forming apparatus according to item (16) ”, (18)“ A fluidizing agent is contained in any of the color toner, the transparent toner and the white toner used in the image forming element, The full color image forming apparatus according to any one of items (1) to (14), wherein the amount of the fluidizing agent contained is substantially the same. Specific resistance of the protective layer of 10¹⁰The full-color image forming apparatus according to any one of (1) to (18) above, which contains an inorganic pigment or metal oxide of Ω · cm or more ”, (20)“ The metal oxidation The specific resistance is 10¹⁰The full-color image forming apparatus as described in (19) above, which is any one of alumina, titanium oxide, and silica of Ω · cm or more ”, (21)“ The metal oxide has a specific resistance of 10 ”.¹⁰The full-color image forming apparatus according to item (20), characterized in that it is α-alumina of Ω · cm or more ”, (22)“ The protective layer contains a polymer charge transport material ” This is solved by the full-color image forming apparatus according to any one of items (19) to (21).
[0028]
Further, (23) “The charge generating substance contained in the electrophotographic photosensitive member is an azo pigment represented by the formula (XI)”. The full-color image forming apparatus according to any one of the above ”, where Cp in the formula₁And Cp₂R in the formula (XII)₂₀₃Represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group. R₂₀₄, R₂₀₅, R₂₀₆, R₂₀₇, R₂₀₈Represents a hydrogen atom, a nitro group, a cyano group, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group, and a hydroxyl group, and Z is A group of atoms necessary for constituting a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring.
[0029]
Further, (24) “Cp of the azo pigment₁And Cp₂The full-color image forming apparatus as described in (23) above, wherein the charge generation material contained in the electrophotographic photosensitive member is a characteristic X-ray of CuKα ( Item (1) to Item (1), wherein the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to a wavelength of 1.542 mm is a titanyl phthalocyanine having a maximum diffraction peak at 27.2 °. 22) The full-color image forming apparatus according to any one of Items 22), (26) “The titanyl phthalocyanine is a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. Furthermore, it has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and a peak at 7.3 °. 9.4 The full-color image forming apparatus according to (25), which does not have a peak between the two peaks and does not have a peak at 26.3 ° ”, (27)“ The electrophotographic photosensitive member ” The surface of the conductive support is subjected to an anodized film treatment, and the full color image forming apparatus according to any one of (1) to (26) above, (28) “the full color image forming” In the apparatus, at least the photosensitive member is in the form of a cartridge housed in one unit together with one means selected from charging means, exposure means, and cleaning means. This is solved by the “full-color image forming apparatus according to any one of items (27)”.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram for explaining an image forming apparatus of the present invention, and the following modifications also belong to the category of the present invention.
[0031]
In FIG. 1, drum-shaped photoconductors 1C, 1M, 1Y, and 1K rotate in the direction of the arrow in the figure, and charging members 2C, 2M, 2Y, and 2K as charging units at least in the order of rotation around the photosensitive members 1C, 1M, 1Y, and 1K. Developing members 4C, 4M, 4Y, and 4K as developing members, developing members 5C, 5M, 5Y, and 5K as transparent toner developing means, charging members for transfer 7C, 7M, 7Y, and 7K, and cleaning members 6C, 6M as cleaning means, 6Y and 6K are arranged.
[0032]
Further, in the image forming element 11Y that first transfers the toner to the intermediate transfer member, the white toner developing unit 13Y is disposed between the transparent toner developing unit 5Y and the transfer unit. A second image exposure unit 14Y is installed between the colored toner developing unit 4Y and the transparent toner developing unit 5Y. Here, the arrangement of the transparent toner developing means 5Y and the white toner developing means 13Y may be reversed.
[0033]
The charging members 2C, 2M, 2Y, and 2K are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. Laser light 3C, 3M, 3Y, and 3K from an exposure member (not shown) as an image exposure unit is irradiated on the surface of the photosensitive member between the charging members 2C, 2M, 2Y, and 2K and the developing members 4C, 4M, 4Y, and 4K. The electrostatic latent images for the colored toner images are formed on the photoreceptors 1C, 1M, 1Y, and 1K. Then, four image forming elements 11C, 11M, 11Y, and 11K centering around the photoreceptors 1C, 1M, 1Y, and 1K are juxtaposed along the intermediate transfer belt 8 that is a transfer unit. The intermediate transfer belt 8 is a photosensitive member 1C, 1M, 1Y, 1K between the transparent toner developing member 5c, 5M, 5Y, 5K or the white toner developing member 13Y and the cleaning members 6C, 6M, 6Y, 6K of each image forming unit. The transfer charging members 7C, 7M, 7Y, and 7K for applying a transfer bias (voltage) are disposed on the surface (back surface) of the transfer conveyance belt 8 that contacts the back side of the photoconductor side. Each of the image forming elements 11C, 11M, 11Y, and 11K is different in the color of the toner inside the color toner developing device, and the 11Y is provided with a white toner developing unit 13Y and a second image exposing unit 14Y. All have the same configuration. Next, the transfer paper 12 is fed out from a paper feed unit (not shown) by the paper feed roller 9 and is transported by the transfer transport belt 16. The transfer paper is in contact with the intermediate transfer belt on the transfer conveyance belt, and a bias is applied between the drive roller (or driven roller) of the transfer conveyance belt and the drive roller (or driven roller) of the intermediate transfer belt. The toner transferred to is transferred onto the transfer paper (secondary transfer).
[0034]
In the color image forming apparatus having the configuration shown in FIG. 1, the image forming operation is performed as follows. First, in each of the image forming elements 11C, 11M, 11Y, and 11K, the photoreceptors 1C, 1M, 1Y, and 1K are charged by charging members 2C, 2M, 2Y, and 2K that rotate in the direction of the arrow (the direction along with the photoreceptor). Then, an electrostatic latent image corresponding to each color image to be created is formed by the laser beams 3C, 3M, 3Y, and 3K in the exposure unit. Next, the latent image is developed by the color toner developing members 4C, 4M, 4Y, and 4K to form a toner image. The colored toner developing members 4C, 4M, 4Y, and 4K are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. Next, in each of the image forming elements 11C, 11M, and 11K, the transparent toner is developed by the transparent toner developing members 5C, 5M, and 5K in a portion (non-image forming area) where the colored toner is not written on the surface of the photoreceptor. In the forming element 11Y, the transparent toner is developed by the transparent toner developing member 5Y, and the colored toner is not developed by the colored toner developing member 4Y, and the colored toner is developed by the other image forming elements 11C, 11M, and 11K. Further, white toner is applied to a portion where the toner is not developed by the colored toner developing member 4Y and the transparent toner developing member 5Y by the white toner developing member 13Y (that is, a portion not developed by all the colored toner developing members 4C, 4M, 4Y, 4K). Developed. Each color, transparent toner, and white toner image formed on the four photoconductors 1C, 1M, 1Y, and 1K are superimposed on the intermediate transfer belt 8.
[0035]
There are at least two methods for developing the transparent toner in each of the image forming elements 11C, 11M, and 11K. The following describes a method in which the color toner is developed by a general negative / positive development using a digital method. One is a method of reversing the charging polarity of the colored toner and the transparent toner. In this case, the colored toner is developed by reversal development on the portion where writing is performed on the photoreceptor, and then the transparent toner is developed by regular development. Of course, when the color toner is developed by regular development, the transparent toner is developed by reversal development. Second, after developing the colored toner, the second exposure members 13C, 13M, and 13K irradiate the photosensitive member with light to lower the surface potential of the non-development area of the colored toner, and develop the transparent toner here. The method of doing is mentioned. An example of this is shown in FIG. In this case, unlike the previous case, the colored toner and the transparent toner have the same charge polarity. At this time, since light is irradiated to the non-development region of the colored toner, light may be irradiated to the entire surface of the photosensitive member. However, it is possible to irradiate only the non-image portion using LD or LED. It is desirable to prevent light fatigue. Such a method can be easily performed by digitally processing the input image signal. In any of the development methods, the development of the transparent toner may be performed in a contact state, but is desirably performed in a non-contact state in order to prevent image disturbance. In order to share the transparent toner used in the image forming element 11K having the white toner developing member, it is desirable to use the same polarity as the colored toner.
[0036]
In the image forming element 11Y having the white toner developing member, the transparent toner is developed in a predetermined position (an area that is not developed by the colored toner developing member 4Y and an area that is developed by another colored toner developing member). Therefore, at least a second exposure means is required in front of the transparent toner developing member, and writing is performed on the surface of the photoreceptor corresponding to the predetermined position, and the transparent toner is developed at that portion. This method is the same as the latter method of the transparent toner developing method in each of the image forming elements 11C, 11M, and 11K described above. In this case as well, the development of the transparent toner may be performed in a contact state, but it is preferable to perform it in a non-contact state in order to prevent image distortion.
[0037]
There are at least two methods for developing the white toner. Depending on the positional relationship between the transparent toner developing member 5Y and the white toner developing member 13Y of the image forming element having the white toner developing means, it is roughly divided into two. When the white toner developing member is present upstream of the transparent toner developing member (the position to be developed on the photosensitive body first), the same method as the transparent toner developing method described above (optical writing is performed at a predetermined location) Development is performed by a method of developing at a location).
[0038]
When the white toner developing member is disposed downstream of the transparent toner developing member (the white toner is developed after developing the transparent toner), there are three methods. The first method is a method in which after transparent toner development, optical writing is performed on the entire surface of the photoreceptor, the surface potential of the photoreceptor is attenuated, and development is performed using white toner having the same charging polarity as the colored toner and transparent toner. is there. The second method performs optical writing only on a portion where white toner is developed (a portion which is not developed by a colored toner developing member and a transparent toner developing member installed in an image forming element having a white toner developing member). In this method, the surface potential is attenuated and development is performed using a white toner having the same charging polarity as the colored toner and the transparent toner. Compared with the previous method, light irradiation is performed only on a necessary portion of the photoconductor, which is a method in accordance with the idea of the present invention that the entire surface of the photoconductor is used uniformly, and this method is more effective than the first method. The effects of the invention can be obtained. The third method is a method of reversing the charging polarity of the white toner from the charging polarity of the colored toner and the white toner used in the same image forming element. Thereby, after the transparent toner development, the white toner can be developed by the regular development in the portion where the surface potential of the photosensitive member is kept high. In any method, the white toner is preferably performed in a non-contact state because it does not disturb the toner layer formed by the colored toner and the transparent toner.
[0039]
The transfer paper 12 is fed from a tray (not shown) by a paper feed roller (not shown), temporarily stopped by a pair of registration rollers 9, and transferred and conveyed belt 16 in synchronization with the image formation on the photosensitive member. Sent to. The transfer paper 12 held on the transfer conveyance belt 16 is conveyed, and the respective color toner, transparent toner and white toner image are transferred at the contact position (secondary transfer portion) with the intermediate transfer belt 8. The toner image on the intermediate transfer belt is transferred onto the transfer paper 12 by an electric field formed from the potential difference between the transfer bias applied by the drive or driven roller 17 of the transfer conveyance belt and the intermediate transfer belt. Then, the recording paper 12 on which the four color toner images are passed through the transfer portion is conveyed to the fixing device 10 where the toner is fixed and discharged to a paper discharge portion (not shown).
Residual toner remaining on the photoreceptors 1C, 1M, 1Y, and 1K without being transferred at the primary transfer portion between the photoreceptor and the intermediate transfer belt is collected by the cleaning devices 6C, 6M, 6Y, and 6K. In the example of FIG. 1, the image forming elements are arranged in the order of colors Y, C, M, and K from the upstream side to the downstream side in the transfer paper conveyance direction, but the order is not limited to this. The order is set arbitrarily. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism that stops the image forming elements 11C, 11M, and 11Y other than black.
Next, the paper passing direction will be described. As shown in FIG. 3A, when the longitudinal direction of the transfer sheet 103 is not aligned with the longitudinal direction of the photosensitive member 101, it is necessary to rotate the photosensitive member many times in order to output one original. On the other hand, as shown in FIG. 3B, by aligning the longitudinal direction of the transfer paper 103 with respect to the longitudinal direction of the photosensitive member 101, the number of rotations is smaller than that in the case of FIG. Can form the same image. Such a method can be easily achieved by rotating the input signal by 90 degrees by digital processing. As a result, the number of rotations of the photoconductor per image output can be reduced, which can contribute to the high durability of the photoconductor. Further, the amount of transparent toner and white toner to be used can be reduced, which is an effective means from the viewpoint of cost reduction and environmental protection. Incidentally, members at both ends in the longitudinal direction of the photoconductor in the drawing are flanges 102 for driving the photoconductor.
[0040]
Further, even if the longitudinal direction of the transfer paper is aligned with the longitudinal direction of the photosensitive member, the longitudinal length of the transfer paper may be shorter than the longitudinal length of the photosensitive member. For example, a photoconductor having a length in the longitudinal direction of A4 is used and an image is formed on a B5 size transfer paper (see FIG. 4). In such a case, even when the longitudinal direction of the transfer paper is aligned with the longitudinal direction of the photoconductor, areas that do not contact the transfer paper appear at both ends or one end of the photoconductor longitudinal direction as shown in FIG. (The shaded area on the photoreceptor in FIG. 4). Usually, in such a case, writing is not performed in this region so that development is not performed even if charging is performed. However, in the present invention, this area is also an area where colored toner is not developed, and transparent toner and white toner are developed. By doing so, the entire surface in the longitudinal direction of the photoreceptor is used uniformly. At this time, it is desirable that the toner to be developed in the shaded area in FIG.
[0041]
FIG. 5 shows a state diagram of the toner layer composed of the color toner, the transparent toner and the white toner developed and transferred onto the transfer paper in this way. As can be seen from the figure, the layer thicknesses of the stacked toner layers are substantially uniform, and the total toner layer thickness on the transfer paper is substantially constant. As a result, the fixing is made uniform, the unevenness of the surface of the toner layer on the transfer paper is reduced, and the glossiness is made uniform over the entire surface. In addition, since each colored toner image is entirely covered with a transparent toner, the toner image of the first color is hardly disturbed during the transfer of the second and subsequent colors, and development is performed faithfully to the electrostatic latent image. , Faithful transcription is done. Thereby, full color image formation with high resolution is performed. As a result, as another effect of the present invention, high image quality of the output image is reproduced in addition to high durability of the photoreceptor and the image forming element. Furthermore, the result is that the surface of the non-image forming area of all the colored toners is covered with the white toner, and the background portion is completely developed with the white toner. As a result, even if ground contamination occurs due to toner dust or a photoreceptor defect in the lower three layers of the stacked toner layers, the result is that the surface is covered with white toner, and the background is covered with soiling. Cannot be recognized. In this way, it is possible to cope with an unexpected error of the image forming element.
[0042]
Next, each member described in FIG. 1 or FIG. 2 will be described. In FIG. 1 or FIG. 2, the charging members 2C, 2M, 2Y, and 2K are in contact with the photoconductor. By providing an appropriate gap (about 10 to 200 μm) between the two, the wear amount of the two can be reduced. In addition to reducing the amount of toner filming on the charging member, it can be used satisfactorily. Such a charging member arranged in a non-contact proximity is a type in which the charging member is arranged in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photosensitive member and the surface of the charging member. If this gap is too large, the charging tends to become unstable, and if it is too small, the surface of the charging member may be contaminated when toner remaining on the photoreceptor exists. . Therefore, the gap is suitably 10 to 200 μm, preferably 10 to 100 μm. From the distance of the air gap, it is distinguished from known charging / wire-type chargers such as corotron and scorotron, contact charging members such as contact-type charging rollers, charging brushes and charging blades.
[0043]
Since the charging member arranged in this proximity is installed in a state where the surface of the charging member is not in contact with the surface of the photosensitive member, there is little toner contamination on the charging member surface, there is little wear on the charging member surface, and the physical surface of the charging member surface is small. This has the advantage of less mechanical / chemical deterioration, and can also realize high durability of the charging member itself. When the above-mentioned problems occur due to the use of contact charging members, and the durability of the charging members is reduced, the charging ability is reduced or the charging becomes uneven in repeated use in the image forming apparatus. Or In order to avoid this charging failure, in repeated use, measures such as increasing the voltage applied to the charging member in accordance with a decrease in charging ability are taken. In this case, the hazard due to charging applied to the photoconductor increases, resulting in a decrease in durability of the photoconductor and generation of abnormal images. Further, as the voltage applied to the charging member increases, the durability of the charging member itself also decreases. However, by using a non-contact charging member, as the charging member becomes highly durable, the charging ability of the charging member is stabilized, so that the charging member, the photoconductor, and eventually the image forming element and the entire system are durable. Stability will be improved.
[0044]
The adjacently arranged charging member used in the present invention may have any shape as long as it has a mechanism capable of appropriately controlling the gap with the surface of the photoreceptor. For example, the rotation shaft of the photosensitive member and the rotation shaft of the charging member may be mechanically fixed so as to have an appropriate gap. Among them, using a charging member in the shape of a charging roller, a gap forming member is disposed at both ends of the non-image forming portion of the charging member, and only this portion is brought into contact with the surface of the photoreceptor, and the image forming region is disposed in a non-contact manner. Alternatively, a method in which a gap forming member at both ends of the photosensitive member non-image forming portion is arranged, and only this portion is brought into contact with the surface of the charging member, and the image forming region is arranged in a non-contact manner can be a simple method to stabilize the gap. It is a method that can be maintained. In particular, the methods described in JP-A Nos. 2002-148904 and 2002-148905 can be used satisfactorily. An example of the proximity charging mechanism in which the gap forming member is arranged on the charging member side is shown in FIG. By using the above-mentioned method, there are advantages such as high charging efficiency and low ozone generation, miniaturization of the apparatus, no contamination by toner, etc., and no mechanical wear due to contact. Because it is used well.
[0045]
Furthermore, as an application method, there is an advantage that uneven charging is less likely to occur by using AC superposition, and it can be used satisfactorily. In particular, in the tandem type full-color image forming apparatus described later, in addition to the problem of uneven density of a halftone image due to uneven charging that occurs in the case of a monochrome image forming apparatus, there is a serious problem of deterioration in color balance (color reproducibility). Connected. The above problem is greatly improved by superimposing the AC component on the DC component, but if the AC component conditions (frequency, peak-to-peak voltage) are too large, the hazard to the photoconductor increases. In some cases, deterioration of the photoconductor may be accelerated. For this reason, superposition of alternating current components should be kept to the minimum necessary.
[0046]
The frequency of the AC component varies depending on the linear velocity of the photosensitive member, but 3 kHz or less, preferably 2 kHz or less is appropriate. Regarding the peak-to-peak voltage, when the relationship between the voltage applied to the charging member and the charging potential to the photoconductor is plotted, there is a region where the photoconductor is not charged despite the voltage being applied, and the charging rises from a certain point. Potential is observed. About twice this rising potential is the optimum potential (usually about 1200 to 1500 V) as the peak-to-peak voltage. However, when the charging ability of the photosensitive member is low or the linear velocity is very high, the peak-to-peak voltage twice the rising potential as described above may be insufficient. On the other hand, when the chargeability is good, the potential stability may be sufficiently exhibited even when it is twice or less. Accordingly, the peak-to-peak voltage is preferably 3 times or less, more preferably 2 times or less of the rising potential. If the peak-to-peak voltage is rewritten as an absolute value, it is desirably used at 3 kV or less, preferably 2 kV or less, more preferably 1.5 kV or less.
[0047]
The image exposure units 3C, 3M, 3Y, and 3K use light sources that can ensure high luminance, such as LEDs, LD, and electroluminescence (EL). Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and are used favorably.
The colored toner developing members 4C, 4M, 4Y, and 4K can be used for both regular development and reversal development depending on the charging polarity of the toner used. When toner having a polarity opposite to the charged polarity of the photoreceptor is used, normal development is used. When toner having the same polarity is used, the electrostatic latent image is developed by reversal development. Depending on the light source used in the previous image exposure unit, in the case of a digital light source used in recent years, there is generally a reversal development method in which toner development is performed on the writing portion in response to a low image area ratio. This is advantageous in view of the life of the light source. In addition, there are two methods, a one-component method in which development is performed only with toner and a two-component method in which a two-component developer composed of toner and carrier is used.
[0048]
The transparent toner developing members 5C, 5M, 5Y, and 5K have the same configuration as that of the colored toner developing member, and the toner to be used is different between colored and transparent. In this case as well, by changing the polarity of the toner, it can be used for both regular development and reversal development (the charging polarity of the colored toner and the transparent toner is the same as described above).
[0049]
In the development of the transparent toner, it is desirable to perform the development in a non-contact state because it does not affect the toner image formed by the colored toner. In the transparent toner developing members 5C, 5M, 5Y, and 5K shown in FIG. 1 or FIG. 2, a vibration bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve as a developing bias by a power source (not shown) during development. Applied. The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed on the transparent toner developing members 5C, 5M, 5Y, and 5K. In this alternating electric field, the developer toner and carrier vibrate vigorously, the toner shakes off the electrostatic binding force on the developing sleeve and carrier, and flies to the photosensitive drums 1C, 1M, 1Y, and 1K. It adheres corresponding to the latent image. The difference (maximum peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 kV, and the frequency is preferably 1 to 10 kHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background portion potential and the image portion potential, but the value closer to the background portion potential than the image portion potential is more likely to cover the background portion potential area. This is preferable for preventing toner adhesion. When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is calmed down, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced. The white toner developing member 13Y has the same configuration as the colored toner developing member and the transparent toner developing member, and the toner to be used differs between colored, transparent and white. As described above, with respect to the charging polarity of the toner, the same polarity as that of the colored and transparent toner is used when the light writing is performed during the development of the white toner, and the opposite polarity is used when the light writing is not performed. The
[0050]
Further, as the light sources of the second and third exposure means arranged as necessary, all luminescent materials such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, LEDs, LDs, ELs, etc. are used. it can. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. In particular, when light irradiation (writing) is performed only on a non-image forming area of colored toner, it is effective to use an LED or an LD.
[0051]
Further, the toner image formed on the photoconductor is finally transferred onto the transfer paper to become an image on the transfer paper. In the present invention, as shown in FIG. The toner image is transferred from the intermediate transfer member to the intermediate transfer member (primary transfer), and further transferred from the intermediate transfer member to the transfer paper.
[0052]
Although the intermediate transfer belt 8 is described as a transfer member in FIG. 1 or FIG. 2, an intermediate transfer roller can also be used. Among them, it is desirable to use a contact type such as a transfer belt or a transfer roller that generates less ozone. Any known transfer member may be used as long as it can satisfy the configuration of the present invention.
[0053]
As the voltage / current application method at the time of primary and secondary transfer, either a constant voltage method or a constant current method can be used. However, the transfer charge amount can be kept constant, and stability can be maintained. A constant current method with excellent resistance is more desirable. In particular, by subtracting the current that flows from the power supply member (high-voltage power supply) that supplies electric charge to the transfer member and does not flow into the photosensitive member, the current to the photosensitive member is subtracted. A method of controlling the value is preferred. Specifically, in order to obtain the current flowing through the roller holding the transfer belt, the related member such as the roller is not directly dropped to the ground, but the current flowing through the related member is returned to the high voltage power source. It is desirable to obtain a difference from the output of the power supply and perform constant current control using a high voltage power supply having a feedback function so that the difference becomes a constant value. The transfer current is a current based on the amount of charge required to peel off the toner electrostatically attached to the photosensitive member and transfer it to a transfer target (transfer paper or intermediate transfer member). In order to avoid transfer defects such as transfer residue, it is only necessary to increase the transfer current. However, when negative / positive development is used, charging with a polarity opposite to the charging polarity of the photoconductor is applied. As a result, the electrostatic fatigue of the photoconductor becomes remarkable. The larger the transfer current, the more advantageous it is because the charge amount exceeding the electrostatic adhesion force between the photoconductor and the toner can be given. As a result, the developed toner image is scattered. For this reason, the upper limit is a range in which this discharge phenomenon does not occur. This threshold varies depending on the gap (distance) between the transfer member and the photoconductor, the material constituting the both, and the like, but the discharge phenomenon can be avoided by using it at about 200 μA or less. Therefore, the upper limit value of the transfer current is about 200 μA.
[0054]
As the cleaning members 6C, 6M, 6Y, and 6K, known members such as a cleaning blade, a cleaning brush, and a cleaning roller can be used. If the transfer rate is high and the amount of toner remaining on the surface of the photoreceptor after transfer is small, this member can be omitted.
[0055]
Although not shown in FIG. 1 or FIG. 2, a static elimination mechanism may be provided between the cleaning members 6C, 6M, 6Y, and 6K and the charging members 2C, 2M, 2Y, and 2K. As the light source of the static elimination mechanism, it is possible to use general luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, LED, LD, and EL. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. When alternating current is applied to the charging members 2C, 2M, 2Y, and 2K, the residual charge on the photosensitive member can be canceled during charging, and thus the static elimination mechanism can be omitted.
[0056]
The image forming means as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. A process cartridge is a single device that includes a photosensitive member 201 and includes a charging unit 202, exposure units 203, 205, and 209, developing units 204, 206, and 208, a transfer unit, a cleaning unit 207, and a discharging unit. (Parts). An example of the process cartridge is shown in FIG.
[0057]
Next, the electrophotographic photosensitive member used in the present invention will be described with reference to the drawings.
FIG. 8 is a cross-sectional view showing a configuration example of the electrophotographic photosensitive member used in the present invention. On the conductive support 31, a charge generation layer 35 mainly composed of a charge generation material and a charge transport material are mainly used. A charge transport layer 37 as a component is laminated, and a surface protective layer 39 having a wear resistance of 0.1 μm or less of wear amount per 10,000 rotations of the photoreceptor in image formation is laminated on the charge transport layer. I'm taking it.
In FIG. 8, the photosensitive layer has a stacked structure of a charge generation layer and a charge transport layer. However, the photosensitive layer may have a single layer structure in which the charge generation material and the charge transport material are contained in the same layer. .
[0058]
The conductive support 31 has a volume resistance of 10¹⁰Films having conductivity of Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, metal oxides such as tin oxide, indium oxide, etc. are deposited or sputtered. Shaped or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc., and cutting them, superfinishing, polishing, etc. A surface-treated tube or the like can be used. Further, an endless nickel belt or an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can also be used as the conductive support 31.
[0059]
Of these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. As used herein, aluminum includes both pure aluminum and aluminum alloys. Specifically, JIS 1000, 3000, and 6000 series aluminum or aluminum alloy is most suitable. The anodized film is obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called anodized aluminum or an aluminum alloy that has been anodized in an electrolyte solution is used in the present invention. Is the most suitable. In particular, it is excellent in preventing point defects (black spots, background stains) that occur when used in reversal development (negative / positive development).
[0060]
The anodizing treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10-20%, bath temperature: 5-25 ° C., current density: 1-4 A / dm²The treatment is performed in the range of electrolytic voltage: 5-30 V, treatment time: 5-60 minutes, but is not limited thereto. Since the anodic oxide film thus produced is porous and has high insulation, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change. In order to avoid this, it is desirable to further seal the anodized film. Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable. Subsequent to the sealing treatment, the anodic oxide film is washed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this remains excessively on the surface of the support (anodized film), it not only adversely affects the quality of the coating film formed on this surface, but also generally low resistance components remain, resulting in the occurrence of soiling. It can also be a cause. Cleaning may be performed with pure water only once, but usually, multistage cleaning is performed. At this time, it is preferable that the final cleaning liquid is as clean (deionized) as possible. Moreover, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning processes. The film thickness of the anodized film formed as described above is desirably about 5-15 μm. If it is thinner than this, the effect of the barrier property as an anodic oxide film is not sufficient, and if it is thicker than this, the time constant as an electrode becomes too large, resulting in the generation of residual potential and the response of the photoreceptor. There is a case.
[0061]
In addition, the conductive support 31 of the present invention can be used in which conductive powder is dispersed in a suitable binder resin and coated on the support. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
[0062]
Furthermore, by a heat shrinkable tube containing the conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. What provided the electroconductive layer can also be used favorably as the electroconductive support body 31 of this invention.
[0063]
Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a laminated layer. For convenience of explanation, the photosensitive layer is first described from the case where it is composed of the charge generation layer 35 and the charge transport layer 37 shown in FIG.
The charge generation layer 35 is a layer mainly composed of a charge generation material.
A known charge generation material can be used for the charge generation layer 35, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycycles. Examples thereof include compounds, squalic acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. These charge generation materials may be used alone or in combination of two or more.
[0064]
In particular, an azo pigment represented by the above formula (XI) or a specific crystal type (at least 27.2 as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to a characteristic X-ray of CuKα (wavelength 1.542 mm)). Since titanyl phthalocyanine (having a maximum diffraction peak at °) has high sensitivity and high durability and is particularly resistant to light fatigue, it can be used effectively in the full-color image forming apparatus of the present invention.
[0065]
In the formula (XI), Cp₁And Cp₂Those having a different value exhibit particularly high sensitivity among the materials represented by the above (XI), and are preferably used as the charge generating material of the photoreceptor of the present invention.
[Chemical Formula 3]

[Formula 4]

Next, Cp₁And Cp₂The case where is different is shown.
[Chemical formula 5]

[Chemical 6]

[Chemical 7]

[Chemical 8]

Among the titanyl phthalocyanines having the maximum diffraction peak at 27.2 °, there are further main peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction peak at the lowest angle is 7%. A titanyl phthalocyanine crystal having a peak at .3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° is particularly sensitive. In addition, the decrease in chargeability due to repeated use of the photoreceptor is small, and it can be used favorably as a charge generating material for the photoreceptor of the present invention.
[0066]
The charge generation layer 35 is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is applied onto a conductive support and dried. It is formed.
As the binder resin used for the charge generation layer 35 as necessary, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N -Vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, etc. Can be mentioned. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material.
[0067]
Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. In particular, ketone solvents, ester solvents, and ether solvents are preferably used. As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used.
[0068]
The thickness of the charge generation layer 35 is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.
The charge transport layer 37 can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
[0069]
Charge transport materials include hole transport materials and electron transport materials. Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.
[0070]
Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.
[0071]
As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol Examples thereof include thermoplastic or thermosetting resins such as resins and alkyd resins. Further, a polymer charge transporting material described later is also suitably used as the binder resin for the charge transporting layer. When a charge transport layer made of a polymer charge transport material is used, a good result is obtained when the surface protective layer described later is laminated because the polymer is made of a polymer so that the charge transport material does not dissolve into the upper layer. There are many cases.
[0072]
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm. Examples of the solvent used here include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.
[0073]
In the photoreceptor of the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 37. As the plasticizer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 0 with respect to the binder resin. 1% by weight is suitable.
[0074]
Next, the case where the photosensitive layer has a single layer structure will be described. A photosensitive layer in which the above-described charge generating material is dispersed in a binder resin can be used. The single-layer photosensitive layer can be formed by dissolving or dispersing a charge generating material and a binder resin in a suitable solvent, and applying and drying the solution. Further, the photosensitive layer may be a function separation type to which the above-described charge transport material is added and can be used satisfactorily. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
[0075]
As the binder resin, the binder resin previously mentioned in the charge transport layer 37 may be used as it is, or the binder resin mentioned in the charge generation layer 35 may be mixed and used. Of course, the polymer charge transport material described later can also be used favorably as the binder resin and the charge transport material. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. A single-layer photosensitive layer is formed by dip coating or spraying with a coating solution dispersed with a disperser using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane together with a charge transport material, if necessary, with a charge generating material and a binder resin. It can be formed by coating with a coat or bead coat. The thickness of the single photosensitive layer is suitably about 5 to 100 μm.
[0076]
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support 31 and the photosensitive layer (charge generation layer). In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.
[0077]
These undercoat layers can be formed using an appropriate solvent and coating method as in the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention includes Al.₂O_ThreeAnodic oxidation, organic materials such as polyparaxylylene (parylene), and SiO₂, SnO₂TiO₂, ITO, CeO₂A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.
In the present invention, in order to improve environmental resistance, for the purpose of preventing a decrease in sensitivity and an increase in residual potential, an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, and a low molecular charge transport material are used for each layer. And leveling agents can be added. Representative materials of these compounds are described below.
[0078]
Examples of the antioxidant that can be added to each layer include, but are not limited to, the following.
(A) Phenolic compounds
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-3- (4-hydroxy-3,5-di -T-butylphenol), 2,2-methylene-bis- (4-methyl-6-t-butylphenol), 2,2-methylene-bis- (4-ethyl-6-t-butylphenol), 4,4- Thiobis- (3-methyl-6-tert-butylphenol), 4,4-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5) -T-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 5-di -t- butyl-4-hydroxyphenyl) propionate] methane, bis [3,3-bis (4-hydroxy -3-t-butylphenyl) butyric Assi de] glycol ester, tocopherols.
(B) Paraphenylenediamines
N-phenyl-N-isopropyl-p-phenylenediamine, N, N-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N-di-isopropyl -P-phenylenediamine, N, N-dimethyl-N, N-di-t-butyl-p-phenylenediamine
Such.
(C) Hydroquinones
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
(D) Organic sulfur compounds
Dilauryl-3,3-thiodipropionate, distearyl-3,3-thiodipropionate, ditetradecyl-3,3-thiodipropionate and the like.
(E) Organophosphorus compounds
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
[0079]
Examples of the plasticizer that can be added to each layer include, but are not limited to, the following.
(A) Phosphate ester plasticizer
Triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichlorethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate and the like.
(B) Phthalate ester plasticizer
Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, phthalic acid Diisodecyl, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate, etc.
(C) Aromatic carboxylic ester plasticizer
Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate and the like.
(D) Aliphatic dibasic acid ester plasticizer
Dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, n-octyl adipate, diisodecyl adipate, dicapryl adipate, diazeylate 2-ethylhexyl, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2-ethoxyethyl sebacate, dioctyl succinate, diisodecyl succinate, Dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like. (E) Fatty acid ester derivatives
Butyl oleate, glycerol monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like.
(F) Oxyester plasticizer
Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.
[0080]
(G) Epoxy plasticizer
Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate and the like.
(H) Dihydric alcohol ester plasticizer
Diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate, etc.
(I) Chlorine-containing plasticizer
Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl, etc.
(J) Polyester plasticizer
Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester, etc.
(K) Sulfonic acid derivative
p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide and the like.
(L) Citric acid derivative
Triethyl citrate, triethyl citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, acetyl citrate-n-octyldecyl, and the like.
(M) Other
Terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietate and the like.
[0081]
Examples of the lubricant that can be added to each layer include, but are not limited to, the following.
(A) Hydrocarbon compounds
Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene, etc.
(B) Fatty acid compounds
Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, etc.
(C) Fatty acid amide compound
Stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide, etc.
(D) Ester compound
Lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, fatty acid polyglycol esters, and the like.
(E) Alcohol compounds
Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol, etc.
(F) Metal soap
Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate, etc.
(G) Natural wax
Carnauba wax, candelilla wax, beeswax, whale wax, ibotarou, montanro, etc.
(H) Other
Silicone compounds, fluorine compounds, etc.
[0082]
Examples of the ultraviolet absorber that can be added to each layer include, but are not limited to, the following.
(A) Benzophenone series
2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2,4-trihydroxybenzophenone, 2,2,4,4-tetrahydroxybenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, and the like.
(B) Salsylate type
Phenyl salsylate, 2,4 di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate, and the like.
(C) Benzotriazole type
(2-hydroxyphenyl) benzotriazole, (2-hydroxy5-methylphenyl) benzotriazole, (2-hydroxy5-methylphenyl) benzotriazole, (2-hydroxy3-tertiarybutyl 5-methylphenyl) 5-chloro Such as benzotriazole.
(D) Cyanoacrylate type
Ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate, and the like.
(E) Quencher (metal complex)
Nickel (2,2thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyldithiocarbamate, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate and the like.
(F) HALS (hindered amine)
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy- 2,2,6,6-tetramethylpiperidine and the like.
[0083]
Further, in the photoreceptor used in the present invention, a surface protective layer 39 is provided on the photosensitive layer for the purpose of protecting the photosensitive layer. As this surface protective layer (hereinafter sometimes abbreviated as a protective layer), it is essential that the protective layer has a wear resistance of 0.1 μm or less per 10,000 rotations of the photoreceptor in image formation. is there.
Materials used for such a protective layer 39 include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl. Sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, Examples thereof include resins such as polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Of these, polycarbonate or polyarylate can be most preferably used.
In addition to the binder resin, a thermosetting resin or a photocurable resin can also be used. Any known thermosetting resin or photocurable resin may be used as long as it exhibits high wear resistance and does not affect the electrophotographic characteristics. In particular, a protective layer made of a cured product obtained by three-dimensional curing (crosslinking) using a polyfunctional monomer or oligomer having three or more functional groups in the molecule has extremely high wear resistance and can be used effectively. I can do it.
[0084]
Other protective layers include fluorine resins such as polytetrafluoroethylene, silicone resins, and inorganic fillers such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving wear resistance. What disperse | distributed the filler etc. can be added.
Among the filler materials used for the protective layer of the photoreceptor, examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like. Metal powders such as copper, tin, aluminum, indium, alumina, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin-doped indium oxide, etc. And inorganic materials such as metal oxides and potassium titanate. In particular, it is advantageous to use an inorganic material among them from the viewpoint of the hardness of the filler. In particular, silica, titanium oxide, and alumina can be used effectively. Furthermore, among these, α-type alumina having a hexagonal close-packed structure can be most effectively used.
[0085]
The filler concentration in the protective layer varies depending on the type of filler used and also on the image forming process conditions using the photoreceptor, but the ratio of the filler to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, preferably It is 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less.
Moreover, the volume average particle diameter of the filler to be used is preferably in the range of 0.1 μm to 2 μm, and preferably in the range of 0.3 μm to 1 μm. In this case, if the average particle size is too small, the wear resistance is not sufficiently exhibited, and if it is too large, the surface property of the coating film is deteriorated or the coating film itself cannot be formed.
[0086]
The average particle diameter of the filler in the present invention is a volume average particle diameter unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. In addition, it is important that the standard deviation of each particle measured simultaneously is 1 μm or less. If the standard deviation is larger than this, the particle size distribution may be too wide, and the effects of the present invention may not be obtained remarkably.
[0087]
Further, the pH of the filler used in the present invention greatly affects the resolution and the dispersibility of the filler. One possible reason is that hydrochloric acid or the like remains in the filler, particularly the metal oxide, during production. When the remaining amount is large, the occurrence of image blur is unavoidable, and depending on the remaining amount, the dispersibility of the filler may be affected.
[0088]
Another reason is due to the difference in chargeability on the surface of the filler, particularly the metal oxide. Usually, particles dispersed in a liquid are charged positively or negatively, and ions having opposite charges gather to try to keep it electrically neutral, and an electric double layer is formed there. The dispersed state of the particles is stabilized. The potential (zeta potential) gradually decreases with increasing distance from the particle, and the potential in a region that is sufficiently away from the particle and electrically neutral is zero. Therefore, the stability increases as the repulsive force of the particles increases due to the increase in the absolute value of the zeta potential, and the particles tend to aggregate and become unstable as they approach zero. On the other hand, the zeta potential varies greatly depending on the pH value of the system, and at a certain pH value, the potential becomes zero and has an isoelectric point. Therefore, the dispersion system is stabilized by increasing the absolute value of the zeta potential as far as possible from the isoelectric point of the system.
[0089]
In the configuration of the present invention, the filler having a pH at the isoelectric point of at least 5 is preferably from the viewpoint of image blur suppression, and the more basic the filler, the higher the effect. It was confirmed that there was. A filler exhibiting basicity having a high pH at the isoelectric point has a higher zeta potential when the system is acidic, thereby improving dispersibility and its stability.
Here, the pH of the filler in the present invention is the pH value at the isoelectric point from the zeta potential. At this time, the zeta potential was measured with a laser zeta potentiometer manufactured by Otsuka Electronics Co., Ltd.
[0090]
Furthermore, as a filler that hardly causes image blur, a filler having high electrical insulation (specific resistance is 10%).¹⁰(Ω · cm or more) is preferable, and those having a filler pH of 5 or more and those having a dielectric constant of 5 or more can be used particularly effectively. In addition, a filler having a pH of 5 or more or a filler having a dielectric constant of 5 or more can be used alone, or two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more can be mixed. It is also possible to use a mixture of two or more fillers having a dielectric constant of 5 or less and a filler having a dielectric constant of 5 or more. Among these fillers, α-type alumina, which has high insulation properties, high thermal stability, and high wear resistance, is a hexagonal close-packed structure, from the viewpoint of suppressing image blur and improving wear resistance. It is particularly useful.
[0091]
The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance value of a powder such as a filler varies depending on the filling rate, it is necessary to measure under certain conditions. In the present invention, the specific resistance value of the filler was measured using an apparatus having the same configuration as the measuring apparatus disclosed in Japanese Patent Laid-Open Nos. 5-94049 and 5-113688, and this value was used. . In the measuring device, the electrode area is 4.0 cm.²It is. Prior to the measurement, a load of 4 kg is applied to the electrode on one side for 1 minute, and the sample amount is adjusted so that the distance between the electrodes is 4 mm. At the time of measurement, the measurement is performed with the weight of the upper electrode (1 kg) loaded, and the applied voltage is measured at 100V. 10⁶The region above Ω · cm was measured with HIGH RESISTING METER (Yokogawa Hewlett Packard), and the region below it was measured with a digital multimeter (Fluk). The specific resistance value thus obtained is defined as the specific resistance value in the present invention.
The dielectric constant of the filler was measured as follows. Using a cell similar to the measurement of the specific resistance as described above, after applying a load, the capacitance was measured, and the dielectric constant was determined from this. For the measurement of the capacitance, a dielectric loss measuring device (Ando Electric) was used.
[0092]
Further, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the fillers. Decreasing the dispersibility of the filler not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem. As the surface treatment agent, all conventionally used surface treatment agents can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, higher fatty acids, etc., or mixed treatment of these with silane coupling agents, Al₂O₃TiO₂, ZrO₂, Silicone, aluminum stearate, etc., or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be used alone or in combination of two or more. The surface treatment amount of the filler is defined by the weight ratio of the surface treatment agent to be used with respect to the filler amount as described above.
[0093]
These filler materials can be dispersed by using an appropriate disperser. Further, from the viewpoint of the transmittance of the protective layer, it is preferable that the filler used is dispersed to the primary particle level and has less aggregates.
[0094]
Further, the protective layer 39 may contain a charge transport material for reducing residual potential and improving responsiveness. As the charge transport material, the materials described in the description of the charge transport layer can be used. When a low molecular charge transport material is used as the charge transport material, a concentration gradient in the protective layer may be provided. In order to improve wear resistance, it is an effective means to reduce the concentration of the surface side. The concentration here refers to the ratio of the weight of the low molecular charge transporting material to the total weight of all the materials constituting the protective layer, and the concentration gradient is a gradient that lowers the concentration on the surface side in the above weight ratio. It shows that.
In addition, a polymer charge transport material having a function as a charge transport material and a binder resin is also preferably used for the protective layer. The protective layer composed of these polymer charge transport materials is not only excellent in wear resistance, but also has an effect of reducing the occurrence of image blur in repeated use, and is very useful in the present invention. As the polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, the polymer charge transport materials represented by the formulas (I) to (X) are favorably used, and these are exemplified below and specific examples are shown.
[0095]
(I) Formula
[Chemical 9]

Where R₁, R₂, R₃Each independently represents a substituted or unsubstituted alkyl group or a halogen atom, R₄Is a hydrogen atom or a substituted or unsubstituted alkyl group, R₅, R₆Is a substituted or unsubstituted aryl group, o, p, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n Represents the number of repeating units and is an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0096]
Embedded image

R₁₀₁, R₁₀₂Each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, -O-, -S-, -SO-, -SO₂-, -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or
Embedded image

In the formula, a is an integer of 1 to 20, b is an integer of 1 to 2000, R₁₀₃, R₁₀₄Represents a substituted or unsubstituted alkyl group or aryl group. Where R₁₀₁And R₁₀₂, R₁₀₃And R₁₀₄May be the same or different.
[0097]
(II) Formula
Embedded image

Where R₇, R₈Is a substituted or unsubstituted aryl group, Ar₁, Ar₂, Ar₃Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0098]
(III) Formula
Embedded image

Where R₉, R₁₀Is a substituted or unsubstituted aryl group, Ar₄, Ar₅, Ar₆Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0099]
(IV) Formula
Embedded image

Where R₁₁, R₁₂ Is a substituted or unsubstituted aryl group, Ar₇, Ar₈, Ar₉Are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as in the case of formula (I). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0100]
(V) Formula
Embedded image

Where R₁₃, R₁₄Is a substituted or unsubstituted aryl group, Ar₁₀, Ar₁₁, Ar₁₂Are the same or different arylene groups, X₁, X₂ Represents a substituted or unsubstituted ethylene group or a substituted or unsubstituted vinylene group. X, k, j and n are the same as in the case of formula (I). In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0101]
(VI) Formula
Embedded image

Where R₁₅, R₁₆, R₁₇, R₁₈Is a substituted or unsubstituted aryl group, Ar₁₃, Ar₁₄, Ar₁₅, Ar₁₆Are the same or different arylene groups, Y₁, Y₂, Y₃Represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group, which may be the same or different. X, k, j and n are the same as in the case of formula (I). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0102]
(VII) Formula
Embedded image

Where R₁₉, R₂₀ Represents a hydrogen atom, a substituted or unsubstituted aryl group, and R₁₉And R₂₀May form a ring. Ar₁₇, Ar₁₈, Ar₁₉ Represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0103]
(VIII) Formula
Embedded image

Where R₂₁Is a substituted or unsubstituted aryl group, Ar₂₀, Ar₂₁, Ar₂₂, Ar₂₃ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0104]
(IX) Formula
Embedded image

Where R₂₂, R₂₃, R₂₄, R₂₅Is a substituted or unsubstituted aryl group, Ar₂₄, Ar₂₅, Ar₂₆, Ar₂₇, Ar₂₈Represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0105]
(X) Formula
Embedded image

Where R₂₆, R₂₇Is a substituted or unsubstituted aryl group, Ar₂₉, Ar₃₀, Ar₃₁Represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0106]
Further, as the polymer charge transport material used in the protective layer, in addition to the polymer charge transport material described above, it is cured after film formation in the state of a monomer or oligomer having an electron donating group when the charge transport layer is formed. A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by carrying out a reaction or a crosslinking reaction.
A protective layer composed of a polymer having these electron donating groups or a polymer having a crosslinked structure is excellent in wear resistance. In general, in an image forming apparatus, since the charging potential (unexposed portion potential) is constant, if the surface layer of the photoconductor is worn by repeated use, the electric field strength applied to the photoconductor increases accordingly. As the electric field strength increases, the occurrence frequency of scumming increases. Therefore, the high wear resistance of the photosensitive member is advantageous for scumming. The protective layer composed of a polymer having these electron-donating groups is a polymer compound, so it has excellent film-forming properties and has a higher density of charge transport sites than a protective layer composed of a low molecular dispersion type polymer. It is possible to form the structure and has excellent charge transport ability. For this reason, a photoreceptor having a protective layer using a polymer charge transport material can be expected to have a high response speed.
Examples of other polymers having an electron donating group include copolymers of known monomers, block polymers, graft polymers, star polymers, and, for example, JP-A-3-109406, JP-A-2000- It is also possible to use a cross-linked polymer having an electron donating group as disclosed in JP-A-206723 and JP-A No. 2001-34001. Also in this case, a material that can satisfy the above mobility can be used effectively.
[0107]
As a method for forming the protective layer, a normal wet coating method is employed. In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer. In addition to the above, a known material such as a-C or a-SiC formed by a vacuum thin film forming method can be used as the protective layer. Next, the developers (colored toner, transparent toner, white toner and carrier) used in the present invention will be described. As the developer used in the present invention, both a one-component developer composed only of toner and a two-component developer composed of toner and carrier can be used favorably.
As the toner constituting the developer together with the electrostatic latent image developing carrier of the present invention, those manufactured by a conventionally known method can be used. A mixture comprising a binder resin, a colorant and a polarity control agent is melt kneaded with a hot roll mill, cooled and solidified, and pulverized and classified. Specifically, it is composed of a binder resin, a colorant, a charge control agent, and optional additives as necessary.
[0108]
Examples of the binder resin include styrene such as polystyrene, poly-p-styrene, and polyvinyltoluene, and homopolymers thereof, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, and styrene-vinyltoluene. Copolymer, styrene-methyl acrylate polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- Butyl methacrylate copolymer, styrene-α-chloro methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer , Styrene-isoprene copolymer, Styrene copolymers such as tylene-maleic acid copolymer, styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, Epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination. .
[0109]
Moreover, the following are mentioned as a polarity control agent used for a toner.
As the polarity control agent for controlling the toner to be negatively charged, for example, organometallic complexes and chelate compounds are effective. Monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acid metal complexes, aromatic dicarboxylic acid metals Complex. Others include aromatic hydroxycarboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, their anhydrides, their esters, and phenol derivatives such as bisphenol.
[0110]
Examples of polarity control agents for controlling the toner to be positively charged include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. And onium salts such as phosphonium salts which are analogs thereof, and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannin Acid, lauric acid, gallic acid, ferricyanide, ferrocyanide).
[0111]
The amount of the polar control agent used in the toner is uniquely determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method. Although not intended, it is preferably used in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin. If it is less than 0.1 part by weight, the charge amount of the toner is insufficient, which is not practical. On the other hand, when the amount exceeds 20 parts by weight, the charge amount of the toner is too large, and the electrostatic attraction force with the carrier is increased, leading to a decrease in developer fluidity and a decrease in image density.
[0112]
Examples of the black colorant contained in the toner include carbon black, aniline black, furnace black, and lamp black. Examples of cyan colorants include phthalocyanine blue, methylene blue, Victoria blue, methyl violet, aniline blue, and ultramarine blue. As the magenta colorant, for example, rhodamine 6G lake, dimethylquinacridone, watching red, rose bengal, rhodamine B, alizarin lake and the like can be used. Examples of yellow colorants include chrome yellow, benzidine yellow, hansa yellow, naphthol yellow, molybdenum orange, quinoline yellow, and tartrazine.
[0113]
In the case of a transparent toner, the transparent toner can be constituted by not adding the colorant to the toner. In addition, various additives described later can be used for the transparent toner, and any additive that can maintain transparency in the state of the toner is used so as not to inhibit the properties (transparency) of the transparent toner.
In the case of white toner, a white colorant is used instead of the colorant used in the color toner. Examples thereof include titanium oxide, zinc oxide, barium sulfate, alumina, and calcium carbonate.
[0114]
In addition to the binder resin and the colorant, a release agent for preventing offset can be added to the toner particles used in the present invention, if necessary. Examples of the release agent include waxes such as low molecular weight polypropylene and low molecular weight polyethylene.
The wax used in the present invention is preferably an ester or olefin. These waxes are generally incompatible with the binder resin used and are easily finely dispersed in the binder. The ester wax has an ester bond, and examples thereof include natural waxes such as carnauba wax, candelilla wax and rice wax, and montan wax. Examples of the olefin wax include synthetic waxes such as polyethylene wax and polypropylene wax.
[0115]
The average dispersion diameter of the wax in the binder resin is preferably 0.2 to 5.0 μm. If it is smaller than 0.2 μm, the effect of exuding the wax cannot be obtained, and the effect of the present invention is hardly exhibited. Further, in order to disperse to 0.2 μm or less, it is necessary to apply excessive dispersion energy to the binder resin at the time of melt kneading, and the resin molecules may be cut and the original function may be lost. On the other hand, if it exceeds 5.0 μm, toner fixing properties, fluidity, storage stability, durability and the like are deteriorated.
The addition amount of the wax is suitably 10% by weight or less with respect to the binder resin. If it exceeds this, the fluidity and offset property of the toner will deteriorate.
Further, the toner can contain a magnetic material and can be used as a magnetic toner. Magnetic materials contained in the magnetic toner include iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel or these metals and aluminum, cobalt, copper, lead, magnesium, tin, zinc and antimony. , Alloys of metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof. These ferromagnetic materials preferably have an average particle size of about 0.05 to 2 μm. The amount of the ferromagnetic material contained in the toner is about 20 to 200 parts by weight, particularly preferably the resin component, with respect to 100 parts by weight of the resin component. It is 40-150 weight part with respect to 100 weight part.
[0116]
Further, as the lubricant to be added to the developer, various fluorine-containing resins such as PTFE, PFA, PVDF, silicone resin, polyolefin resin, zinc stearate, zinc laurate, zinc myristate, calcium stearate, aluminum stearate, etc. Examples include fatty acid metal salts. Of these, zinc stearate is most preferable. The amount of lubricant added to the developer is desirably in the range of 0.001 to 0.2% by weight with respect to the toner in the developer.
[0117]
Examples of the fluidizing agent added to the developer include colloidal silica, hydrophobic silica, Teflon (registered trademark), fluoropolymer, low molecular weight polyolefin, fatty acid metal salt (zinc stearate, aluminum stearate, calcium stearate). Etc.), metal oxides (titanium oxide, aluminum oxide, tin oxide, antimony oxide, etc.), conductivity imparting agents (carbon black, tin oxide, etc.), magnetic materials, and those obtained by surface treatment of these additives. It is done. Among them, inorganic resin fine particles such as silica, titania, alumina, cerium oxide, strontium titanate, calcium carbonate, magnesium carbonate, and calcium phosphate, organic resin fine particles such as fluorine-containing resin fine particles, silica-containing resin fine particles, and nitrogen-containing resin fine particles. preferable. These fluidizing agents may be used alone or in combination of two or more, and the content is generally 0.1 to 10 parts by weight per 100 parts of toner. Moreover, you may surface-treat on the surface of an external additive according to the objective. Examples of the surface treatment agent include a silane compound, a silane coupling agent, and a silicone oil for performing a hydrophobic treatment.
[0118]
Furthermore, it is preferable to contain two or more kinds of external additives having different particle diameters, and it is preferable to contain an external additive having a particle diameter difference of about 2 to 5 times in average particle diameter. When two or more types of external additives having different particle diameters are not contained, the external additive is rapidly embedded in the toner base material over time, and toner fluidity is rapidly deteriorated. Therefore, image unevenness due to a decrease in the fluidity of the toner is likely to occur, the adhesive force to the toner is difficult to be increased, and the toner is easily detached from the toner, causing a photosensitive material scratch and an image blur. If two or more types of external additives with different particle sizes are contained, the large particle size external additive acts as a spacer, preventing the embedding of the small particle size external additive effective in toner fluidity in the toner base Thus, toner fluidity can be maintained.
[0119]
The toner configured as described above is desirably the same in colored toner, transparent toner, and white toner, except for the presence or absence of a colorant and the color of the colorant used. In particular, when waxes are used and when a fluidizing agent is used, the amount of wear of the photoreceptor is affected, so the amounts of both the colored toner, the transparent toner and the white toner are almost the same. This is very important.
When waxes are used, the waxes are transferred to the surface of the photoconductor, thereby reducing the amount of wear on the surface of the photoconductor in the cleaning portion. For this reason, when the added amount of the waxes contained in the colored toner, the transparent toner and the white toner is substantially the same, the wear amount of the photoreceptor in repeated use is made uniform in the direction of smallness. As side effects when using waxes, toner filming and image blurring on the surface of the photoreceptor may occur. Therefore, although it depends on the composition of the photoreceptor surface, it is necessary to determine process conditions so that such a phenomenon does not occur.
[0120]
When a lubricant is used, the lubricant adheres to the surface of the photoconductor, thereby improving the cleaning performance of residual toner in the cleaning portion and reducing the amount of wear on the surface of the photoconductor. For this reason, when the addition amount of the lubricant contained in the colored toner, the transparent toner, and the white toner is substantially the same, the wear amount of the photoconductor in repeated use is made uniform in a small direction. As a side effect when using a lubricant, image blur may occur. Therefore, although it depends on the composition of the photoreceptor surface, it is necessary to determine process conditions so that such a phenomenon does not occur.
When a fluidizing agent is used, when the fluidizing agent adheres to the surface of the photoconductor and the residual fluidizing agent reaches the cleaning portion, there is a function of promoting wear of the photoconductor. For this reason, when the addition amount of the fluidizing agent contained in the color toner, the transparent toner, and the white toner is almost the same, the amount of wear of the photoconductor in repeated use is made uniform in a direction in which it is large. As a side effect when a fluidizing agent is used, the amount of wear on the surface of the photoconductor increases, and abnormal images such as streaks can be generated and the life of the photoconductor can be shortened. Therefore, although it depends on the composition of the photoreceptor surface, it is necessary to determine process conditions so that such a phenomenon does not occur.
[0121]
Examples of the carrier that can be used in the present invention include magnetic powders such as iron powder, ferrite powder and nickel powder, and those whose surfaces are treated with a resin or the like. In order to further stabilize the triboelectric chargeability of the toner used in the present invention and to faithfully develop the latent image, the carrier used in the present invention is preferably coated with a resin and / or a silicone compound. This can be performed for the purpose of toner charge control.
As the resin for forming the carrier coating layer, for example, a silicone compound, a fluorine resin, or the like can be preferably used. Examples of the fluororesin for forming the carrier coating layer include perfluoropolymers such as polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, and polytrifluoroethylene, polytetrafluoroethylene, and polyperfluoro Olpropylene, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and trifluoroethylene, copolymer of tetrafluoroethylene and hexafluoropropylene, vinyl fluoride and fluoride Copolymers of vinylidene, copolymers of vinylidene fluoride and tetrafluoroethylene, copolymers of vinylidene fluoride and hexafluoropropylene, terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers Fluoroterpolymer like It is preferably used. In the formation of the carrier coating layer, the fluororesins as described above may be used alone, or a blend of these may be used. Moreover, you may use what blended another polymer further to these.
[0122]
As the silicone compound for forming the carrier coating layer, polysiloxanes such as dimethylpolysiloxane and phenylmethylpolysiloxane are all used, and alkyd-modified silicone, epoxy-modified silicone, polyester-modified silicone, and urethane. Modified resins such as modified silicone and acrylic modified silicone can also be used. As the modified form, any of a block copolymer, a graft copolymer, a comb graft polysiloxane, and the like can be used.
In the actual application to the surface of the magnetic particles, a method of spraying the resin on the magnetic particles by a dipping method or a fluidized bed method is used.
[0123]
As the material of the carrier core material used in the present invention, for example, surface oxidized or unoxidized iron, nickel, cobalt, manganese, chromium, rare earth and other metals and their alloys or oxides can be used. Preferably metal oxides, more preferably ferrite particles can be used. Moreover, there is no special restriction | limiting as the manufacturing method. The carrier and toner used in the present invention are preferably mixed so that the toner particles adhere to the carrier surface of the carrier particles and occupy 30 to 90% of the surface area.
[0124]
【Example】
Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by an example. All parts are parts by weight.
<Synthesis of titanyl phthalocyanine A>
292 g of 1,3-diiminoisoindoline and 2000 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained. Dissolve the crude titanyl phthalocyanine in 20 times the amount of concentrated sulfuric acid, add dropwise to 100 times the amount of ice water with stirring, filter the precipitated crystals, and then repeat washing with water until the washing solution becomes neutral. Got. 20 g of the obtained wet cake was put into 200 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine A powder.
[0125]
<Synthesis of titanyl phthalocyanine B>
Crude titanyl phthalocyanine was obtained in the same manner as the synthesis process of titanyl phthalocyanine A, and a wet cake of titanyl phthalocyanine pigment was obtained in the same manner by acid paste treatment with concentrated sulfuric acid. 20 g of the obtained wet cake was put into 200 g of 2-butanone, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine B powder.
[0126]
<Synthesis of titanyl phthalocyanine C>
20 g of titanyl phthalocyanine B powder synthesized as described above was subjected to a ball milling treatment with 200 g of tetrahydrofuran for 24 hours, followed by filtration and drying to obtain titanyl phthalocyanine C powder.
The titanyl phthalocyanines A, B, and C synthesized as described above were measured for X-ray diffraction spectra under the following measurement conditions.
[0127]
(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min
Scanning range: 3 ° -40 °
Time constant: 2 seconds
[0128]
X-ray diffraction spectra of titanyl phthalocyanines A, B and C are shown in FIGS.
From FIG. 9, the X-ray diffraction spectrum of titanyl phthalocyanine A has a maximum peak at a Bragg angle 2θ of 27.2 ± 0.2 ° with respect to the Cu—Kα ray (wavelength 1.542 mm), and further 9.4 °. It has major peaks at 9.6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, with 7.3 ° and 9.4 ° peaks. It can be seen that there is no peak in between and no peak at 26.3 °.
[0129]
From FIG. 10, the X-ray diffraction spectrum of titanyl phthalocyanine B has a maximum peak at a Bragg angle 2θ of 27.2 ± 0.2 ° with respect to the Cu-Kα ray (wavelength 1.542 mm) and the lowest angle side. It can be seen that the diffraction peak has a peak at 7.5 °.
[0130]
FIG. 11 shows that the X-ray diffraction spectrum of titanyl phthalocyanine B has a maximum peak at a Bragg angle 2θ of 26.3 ± 0.2 ° with respect to the Cu—Kα ray (wavelength 1.542 波長).
Thus, it turns out that titanyl phthalocyanine A, B, C is a titanyl phthalocyanine from which a crystal form differs, respectively.
[0131]
<Preparation of Photoreceptor 1>
Undercoat layer coating solution, charge generation layer coating solution, charge transport layer coating solution and protective layer coating solution of the following composition are sequentially applied and dried on an aluminum cylinder (JIS 3010) having a length of 340 mm and a diameter of 30 mm. An electrophotographic photoreceptor comprising a 3.5 μm intermediate layer, a 0.2 μm charge generation layer, a 20 μm charge transport layer, and a 5 μm protective layer was formed.
◎ Undercoat layer coating solution
400 parts of titanium dioxide powder
65 parts of melamine resin
120 parts alkyd resin
2-butanone 400 parts
[0132]
◎ Charge generation layer coating solution
Disazo pigment with the following structure: 8 parts
Embedded image

Polyvinyl butyral 5 parts
2-butanone 200 parts
400 parts of cyclohexanone
[0133]
◎ Charge transport layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
[0134]
7 parts of charge transport material with the following structural formula
Embedded image

80 parts of tetrahydrofuran
[0135]
◎ Protective layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
7 parts of charge transport material with the following structural formula
[0136]
Embedded image

α-alumina fine particles (specific resistance: 2.5 × 10¹²Ω · cm,
(Average primary particle size: 0.4 μm) 6 parts
150 parts of cyclohexanone
Tetrahydrofuran 500 parts
[0137]
<Preparation of Photoreceptor 2>
In the production of the photoconductor 1, a photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer was not provided and the thickness of the charge transport layer was changed to 25 μm.
[0138]
<Preparation of Photoreceptor 3>
A photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer coating solution was changed to the following in the production of the photoconductor 1.
◎ Protective layer coating solution
15 parts of polymer charge transport material of the following structural formula
[0139]
Embedded image

(As a result of measuring the molecular weight by GPC, n was about 230.)
150 parts of cyclohexanone
Tetrahydrofuran 500 parts
[0140]
<Preparation of Photoreceptor 4>
A photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer coating solution was changed to the following in the production of the photoconductor 1.
◎ Protective layer coating solution
13 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
8 parts of charge transport material of the following structural formula
[0141]
Embedded image

α-alumina fine particles (specific resistance: 2.5 × 10¹²Ω · cm,
Average primary particle size: 0.4 μm) 1 part
200 parts of cyclohexanone
Tetrahydrofuran 600 parts
[0142]
<Preparation of Photoreceptor 5>
A photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer coating solution was changed to the following in the production of the photoconductor 1.
[0143]
◎ Protective layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
[0144]
7 parts of charge transport material with the following structural formula
Embedded image

Silica fine powder (specific resistance: 4 × 10¹³Ω · cm,
(Average primary particle size: 0.3 μm) 8 parts
150 parts of cyclohexanone
Tetrahydrofuran 500 parts
[0145]
<Preparation of Photoreceptor 6>
A photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer coating solution was changed to the following in the production of the photoconductor 1.
[0146]
◎ Protective layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
[0147]
7 parts of charge transport material with the following structural formula
Embedded image

Titanium oxide fine particles (specific resistance: 1.5 × 10¹⁰Ω · cm,
(Average primary particle size: 0.5 μm) 7 parts
150 parts of cyclohexanone
Tetrahydrofuran 500 parts
[0148]
<Preparation of photoconductor 7>
A photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer coating solution was changed to the following in the production of the photoconductor 1.
[0149]
◎ Protective layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
7 parts of charge transport material with the following structural formula
[0150]
Embedded image

Tin oxide-antimony oxide powder (specific resistance: 10⁶Ω · cm,
(Average primary particle size 0.4 μm) 6 parts
150 parts of cyclohexanone
Tetrahydrofuran 500 parts
[0151]
<Preparation of photoconductor 8>
A photoconductor was produced in the same manner as the photoconductor 1 except that the protective layer coating solution was changed to the following in the production of the photoconductor 1.
[0152]
◎ Protective layer coating solution
17 parts of polymer charge transport material of the following structural formula
Embedded image

(As a result of measuring the molecular weight by GPC, n was about 250.)
α-alumina fine particles (specific resistance: 2.5 × 10¹²Ω · cm,
(Average primary particle size: 0.4 μm) 6 parts
300 parts of cyclohexanone
800 parts of tetrahydrofuran
[0153]
<Preparation of photoconductor 9>
A photoconductor was produced in the same manner as the photoconductor 1 except that the charge generation layer coating solution was changed to the following in the production of the photoconductor 1.
◎ Charge generation layer coating solution
Disazo pigment with the following structure: 8 parts
Embedded image

Polyvinyl butyral 5 parts
2-butanone 200 parts
400 parts of cyclohexanone
[0154]
<Preparation of Photoreceptor 10>
A photoconductor was produced in the same manner as the photoconductor 1 except that the charge generation layer coating solution was changed to the following in the production of the photoconductor 1.
◎ Charge generation layer coating solution
Disazo pigment with the following structure: 8 parts
Embedded image

Polyvinyl butyral 5 parts
2-butanone 200 parts
400 parts of cyclohexanone
[0155]
<Preparation of Photoreceptor 11>
An undercoating layer coating solution, a charge generation layer coating solution, a charge transport layer coating solution and a protective layer coating solution having the following composition are sequentially applied and dried on an aluminum cylinder (JIS 3010) having a diameter of 30 mm, and 3.5 μm. An electrophotographic photoreceptor comprising an intermediate layer, a 0.2 μm charge generation layer, a 20 μm charge transport layer, and a 5 μm protective layer was formed.
◎ Undercoat layer coating solution
400 parts of titanium dioxide powder
65 parts of melamine resin
120 parts alkyd resin
2-butanone 400 parts
[0156]
◎ Charge generation layer coating solution
15 parts of previously synthesized titanyl phthalocyanine A
Polyvinyl butyral 10 parts
280 parts of 2-butanone
[0157]
◎ Charge transport layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
[0158]
7 parts of charge transport material with the following structural formula
Embedded image

80 parts of tetrahydrofuran
[0159]
◎ Protective layer coating solution
10 parts of polycarbonate with the following structure
Embedded image

(The viscosity average molecular weight is about 50,000.)
[0160]
7 parts of charge transport material with the following structural formula
Embedded image

α-alumina fine particles (specific resistance: 2.5 × 10¹²Ω · cm,
(Average primary particle size: 0.4 μm) 6 parts
150 parts of cyclohexanone
Tetrahydrofuran 500 parts
[0161]
<Preparation of Photoreceptor 12>
In the production of the photoreceptor 11, an aluminum cylinder (JIS1050) is subjected to the following anodic oxide film treatment, and then a charge generation layer, a charge transport layer, and a protective layer are provided in the same manner as the photoreceptor 11 without providing an undercoat layer. A photoconductor was prepared.
[0162]
◎ Anodic oxide film treatment
The surface of the support was mirror-polished, degreased and washed with water, then immersed in an electrolytic bath at a liquid temperature of 20 ° C. and sulfuric acid of 15 vol%, and an anodized film was treated at an electrolysis voltage of 15 V for 30 minutes. Further, after washing with water, sealing treatment was performed with a 7% nickel acetate aqueous solution (50 ° C.). Thereafter, washing with pure water was performed to obtain a support on which a 6 μm anodic oxide film was formed.
[0163]
<Preparation of Photoreceptor 13>
A photoconductor was produced in the same manner as the photoconductor 11 except that the charge generation layer coating solution was changed to the following in the production of the photoconductor 11.
[0164]
◎ Charge generation layer coating solution
15 parts of previously synthesized titanyl phthalocyanine B
Polyvinyl butyral 10 parts
280 parts of 2-butanone
[0165]
<Preparation of Photoreceptor 14>
A photoconductor was produced in the same manner as the photoconductor 11 except that the charge generation layer coating solution was changed to the following in the production of the photoconductor 11.
[0166]
◎ Charge generation layer coating solution
15 parts of previously synthesized titanyl phthalocyanine C
Polyvinyl butyral 10 parts
280 parts of 2-butanone
[0167]
<Preparation of Black Toner Developer K-1>
(Black toner)
95 parts of polyester resin
Carnauba wax 5 parts
10 parts of carbon black
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm.
[0168]
Further, 2 parts by weight of polyvinyl alcohol and 60 parts by weight of water were placed in a ball mill with respect to 100 parts by weight of magnetite produced by a wet method, and mixed for 12 hours to prepare a magnetite slurry. This slurry was sprayed and granulated with a spray dryer to obtain spherical particles. The particles were fired in a nitrogen atmosphere at a temperature of 1000 ° C. for 3 hours and then cooled to obtain core particles 1.
100 parts of silicone resin solution
100 parts of toluene
γ-aminopropyltrimethoxysilane 15 parts
20 parts of carbon black
[0169]
The said mixture was disperse | distributed for 20 minutes with the homomixer, and the coating layer forming liquid 1 was prepared. The coating layer forming liquid 1 was coated on the surface of 1000 parts of the core particles 1 using a fluidized bed coating apparatus to obtain a silicone resin-coated carrier A (magnetic carrier A).
The magnetic carrier A was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a two-component developer (K-1).
[0170]
<Preparation of Yellow Toner Developer Y-1>
(Yellow toner)
95 parts of polyester resin
Carnauba wax 5 parts
C. I. 5 parts of Pigment Yellow 180
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (Y-1).
[0171]
<Preparation of Magenta Toner Developer M-1>
(Magenta toner)
95 parts of polyester resin
Carnauba wax 5 parts
C. I. Pigment Red 57: 1 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (M-1).
[0172]
<Preparation of Cyan Toner Developer C-1>
(Cyan toner)
95 parts of polyester resin
Carnauba wax 5 parts
C. I. Pigment Blue 15: 3 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (C-1).
[0173]
<Preparation of Transparent Toner Developer T-1>
(Transparent toner)
95 parts of polyester resin
Carnauba wax 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (T-1).
[0174]
<Preparation of White Toner Developer W-1>
(White toner)
95 parts of polyester resin
Carnauba wax 5 parts
Titanium oxide 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (W-1).
[0175]
<Preparation of Black Toner Developer K-2>
(Black toner)
100 parts of polyester resin
10 parts of carbon black
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.0 μm. To the toner, titanium oxide fine particles 1 wt% and silica fine particles 1 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (K-2).
[0176]
<Preparation of Yellow Toner Developer Y-2>
(Yellow toner)
100 parts of polyester resin
C. I. 5 parts of Pigment Yellow 180
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.0 μm. To the toner, titanium oxide fine particles 1 wt% and silica fine particles 1 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (Y-2).
[0177]
<Preparation of Magenta Toner Developer M-2>
(Magenta toner)
100 parts of polyester resin
C. I. Pigment Red 57: 1 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.0 μm. To the toner, titanium oxide fine particles 1 wt% and silica fine particles 1 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (M-2).
[0178]
<Preparation of Cyan Toner Developer C-2>
(Cyan toner)
100 parts of polyester resin
C. I. Pigment Blue 15: 3 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.0 μm. To the toner, titanium oxide fine particles 1 wt% and silica fine particles 1 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (C-2).
[0179]
<Preparation of Transparent Toner Developer T-2>
(Transparent toner)
100 parts of polyester resin
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.0 μm. To the toner, titanium oxide fine particles 1 wt% and silica fine particles 1 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (T-2).
[0180]
<Preparation of white toner developer W-2>
(White toner)
100 parts of polyester resin
Titanium oxide 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.0 μm. To the toner, titanium oxide fine particles 1 wt% and silica fine particles 1 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (W-2).
[0181]
<Preparation of Black Toner Developer K-3>
(Black toner)
100 parts of polyester resin
10 parts of carbon black
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.5 μm. To the toner, 0.9 wt% of titanium oxide fine particles, 0.9 wt% of silica fine particles, and 0.2 wt% of zinc stearate (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (K-3).
[0182]
<Preparation of Yellow Toner Developer Y-3>
(Yellow toner)
100 parts of polyester resin
C. I. 5 parts of Pigment Yellow 180
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.5 μm. To the toner, 0.9 wt% of titanium oxide fine particles, 0.9 wt% of silica fine particles, and 0.2 wt% of zinc stearate (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (Y-3).
[0183]
<Preparation of Magenta Toner Developer M-3>
(Magenta toner)
100 parts of polyester resin
C. I. Pigment Red 57: 1 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.5 μm. To the toner, 0.9 wt% of titanium oxide fine particles, 0.9 wt% of silica fine particles, and 0.2 wt% of zinc stearate (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (M-3).
[0184]
<Preparation of Cyan Toner Developer C-3>
(Cyan toner)
100 parts of polyester resin
C. I. Pigment Blue 15: 3 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.5 μm. To the toner, 0.9 wt% of titanium oxide fine particles, 0.9 wt% of silica fine particles, and 0.2 wt% of zinc stearate (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (C-3).
[0185]
<Preparation of Transparent Toner Developer T-3>
(Transparent toner)
100 parts of polyester resin
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.5 μm. To the toner, 0.9 wt% of titanium oxide fine particles, 0.9 wt% of silica fine particles, and 0.2 wt% of zinc stearate (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (T-3).
[0186]
<Preparation of White Toner Developer W-3>
(Cyan toner)
100 parts of polyester resin
Titanium oxide 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 7.5 μm. To the toner, 0.9 wt% of titanium oxide fine particles, 0.9 wt% of silica fine particles, and 0.2 wt% of zinc stearate (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier A to prepare a two-component developer (W-3).
[0187]
<Preparation of Black Toner Developer K-4>
(Black toner)
100 parts of polyester resin
10 parts of carbon black
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm.
Silica fine particles 1.5 wt% and zinc stearate 0.2 wt% (both to the toner) were externally added to the toner. The magnetic carrier A was mixed with 97.5 parts of toner in a ratio of 2.5 parts of toner to prepare a two-component developer (K-4).
[0188]
<Preparation of Yellow Toner Developer Y-4>
(Yellow toner)
95 parts of polyester resin
C. I. 5 parts of Pigment Yellow 180
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm. Silica fine particles 1.5 wt% and zinc stearate 0.2 wt% (both to the toner) were externally added to the toner. The magnetic carrier A was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a two-component developer (Y-4).
[0189]
<Preparation of Magenta Toner Developer M-4>
(Magenta toner)
95 parts of polyester resin
C. I. Pigment Red 57: 1 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm.
Silica fine particles 1.5 wt% and zinc stearate 0.2 wt% (both to the toner) were externally added to the toner. The magnetic carrier A was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a two-component developer (M-4).
[0190]
<Preparation of Cyan Toner Developer C-4>
(Cyan toner)
95 parts of polyester resin
C. I. Pigment Blue 15: 3 5 parts
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm.
Silica fine particles 1.5 wt% and zinc stearate 0.2 wt% (both to the toner) were externally added to the toner. The magnetic carrier A was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a two-component developer (C-4).
[0191]
<Preparation of Transparent Toner Developer T-4>
(Transparent toner)
95 parts of polyester resin
Salicylic acid derivative zinc salt 2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm.
Silica fine particles 1.5 wt% and zinc stearate 0.2 wt% (both to the toner) were externally added to the toner. The magnetic carrier A was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a two-component developer (T-4).
[0192]
<Preparation of white toner developer W-4>
(White toner)
95 parts of polyester resin
Titanium oxide 5 parts
Quaternary ammonium-based charge control agent (Hodogaya Chemical, "TP-415")
2 parts
The mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 μm.
Further, 2 parts by weight of polyvinyl alcohol and 60 parts by weight of water were placed in a ball mill with respect to 100 parts by weight of magnetite produced by a wet method, and mixed for 12 hours to prepare a magnetite slurry. This slurry was sprayed and granulated with a spray dryer to obtain spherical particles. The particles were fired in a nitrogen atmosphere at a temperature of 1000 ° C. for 3 hours and then cooled to obtain core particles.
100 parts of silicone resin solution
100 parts of toluene
20 parts of carbon black
The mixture was dispersed with a homomixer for 20 minutes to prepare a coating layer forming liquid 2. The coating layer forming liquid 2 was coated on the surface of 1000 parts of the core particles 1 using a fluidized bed type coating apparatus to obtain a silicone resin coated carrier B (magnetic carrier B).
Silica fine particles 1.5 wt% and zinc stearate 0.2 wt% (both to the toner) were externally added to the toner. The magnetic carrier B was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a two-component developer (W-4). Developer W-4 is a positively charged developer.
[0193]
<Example 1>
The photoreceptor 1 was set on the cartridge shown in FIG. 7A, and three image forming elements (M, C, K) were prepared. Further, the photosensitive member 1 was set in the cartridge shown in FIG. 7B, and one image forming element (Y) was prepared. These image forming element cartridges were mounted on the image forming apparatus shown in FIG. K-1, Y-1, M-1, and C-1 developers are added to the colored toner developing portions of each image forming element, and T-1 developer is supplied to all the transparent toner developing portions. did. Further, the developer of W-1 was charged into the white toner developing portion mounted on the image forming element (Y) (both of them were negatively charged and reversely developed in the image light writing portion). As the charging member, a non-contact charging roller as shown in FIG. 6 (the gap between the roller surface and the photoreceptor surface in the image forming area is 50 μm) is used. (DC bias: -600 V, AC bias: 2.0 kV (peak to peak), frequency: 1.2 kHz). Writing was performed at a writing density of 600 dpi using a 655 nm LD (beam diameter 50 μm on the surface of the photoreceptor) as an exposure light source (first writing light) for forming a colored toner image (the irradiation energy at the solid part is 4.0 erg). In the M, C, and K image forming elements, a 670 nm LED was used as the second exposure light source, and after color toner development, the entire surface of each photoconductor was irradiated with light to develop transparent toner. In the Y image forming element, 655 nm LD is used as the second exposure light source, and after developing the colored toner, writing is performed only on the developed portion of the M, C, K colored toner, and the transparent toner is developed. Further, using a 670 nm LED as a third exposure light source, the entire surface of the photoreceptor was irradiated with light to develop white toner. All developments were performed in a non-contact manner. A scorotron charger was used as the transfer charging member, and the transfer current was controlled to 35 μA. A blade made of urethane rubber was used as the cleaning member.
[0194]
Under the above conditions, the A4 original shown in FIG. 12 was output 100,000 images in the direction in which the longitudinal direction of the paper and the longitudinal direction of the photosensitive member are aligned. Images after the fifth and 100,000th sheet were evaluated. Further, after outputting 100,000 sheets, a white solid image was output for each of Y, M, C, and K, each halftone image. All of the above image evaluations were performed on A4 paper (aligned with the longitudinal direction of the photoreceptor and the longitudinal direction of the paper). Further, the photoconductor was taken out from the cartridge, and the film thickness distribution in the longitudinal direction of the photoconductor was measured. The results are shown in Table 1.
[0195]
<Example 2>
In the experiment of Example 1, K-2, Y-2, M-2, C-2, T-2, and W-2 were used as a colored toner developer, a transparent toner developer, and a white toner developer. Evaluation was performed in the same manner as in Example 1 except that. The results are shown in Table 1.
[0196]
<Example 3>
In the experiment of Example 1, K-3, Y-3, M-3, C-3, T-2, and W-2 were used as the color toner developer, the transparent toner developer, and the white toner developer. Except for the above, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
[0197]
<Comparative Example 1>
In the experiment of Example 1, evaluation was performed in the same manner as in Example 1 except that the second exposure member, the transparent toner developing member, the third exposure member, and the white toner developing member were removed from the image forming apparatus and image formation was performed. Went. The results are shown in Table 1.
[0198]
<Comparative example 2>
In the experiment of Example 2, evaluation was performed in the same manner as in Example 2 except that the second exposure member, the transparent toner developing member, the third exposure member, and the white toner developing member were removed from the image forming apparatus and image formation was performed. Went. The results are shown in Table 1.
[0199]
<Comparative Example 3>
In the experiment of Example 3, evaluation was performed in the same manner as in Example 3 except that the second exposure member, the transparent toner developing member, the third exposure member, and the white toner developing member were removed from the image forming apparatus and image formation was performed. Went. The results are shown in Table 1.
[0200]
<Comparative example 4>
In the experiment of Example 1, evaluation was performed in the same manner as in Example 1 except that the third exposure member and the white toner developing member were removed from the image forming apparatus and image formation was performed. The results are shown in Table 1.
[0201]
<Comparative Example 5>
In the experiment of Example 2, evaluation was performed in the same manner as in Example 2 except that the third exposure member and the white toner developing member were removed from the image forming apparatus and image formation was performed. The results are shown in Table 1.
[0202]
<Comparative Example 6>
In the experiment of Example 3, the evaluation was performed in the same manner as in Example 3 except that the third exposure member and the white toner developing member were removed from the image forming apparatus and image formation was performed. The results are shown in Table 1.
[0203]
<Comparative Example 7>
In the experiment of Example 3, the evaluation was performed in the same manner as in Example 3 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 2. The results are shown in Table 1.
[0204]
<Comparative Example 8>
In the experiment of Example 3, evaluation was performed in the same manner as in Example 3 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 3. The results are shown in Table 1.
[0205]
<Comparative Example 9>
In the experiment of Example 3, the evaluation was performed in the same manner as in Example 3 except that the photoconductors mounted on all the image forming element cartridges were changed to the photoconductors 4. The results are shown in Table 1.
[0206]
<Example 4>
In the experiment of Example 3, the evaluation was performed in the same manner as in Example 3 except that the third exposure member was set to 655 nm LD and writing was performed only on the white toner image forming unit (all colored toner non-image forming units). . The results are shown in Table 1.
[0207]
<Example 5>
In the experiment of Example 3, the evaluation was performed in the same manner as in Example 3 except that the second exposure member mounted on all the image forming elements was set to 655 nm LD and writing was performed only on the transparent toner image forming unit. The results are shown in Table 1.
[0208]
<Example 6>
In the experiment of Example 3, K-4, Y-4, M-4, C-4, T-4, and W-4 were used as a colored toner developer, a transparent toner developer, and a white toner developer. Evaluation was performed in the same manner as in Example 3 except that the third exposure member was removed from the forming element (Y) (configuration shown in FIGS. 1 and 7C) and white toner was developed by regular development. . The results are shown in Table 1.
[0209]
<Example 7>
In the experiment of Example 5, the longitudinal direction of A4 paper was output at right angles to the longitudinal direction of the photoreceptor. At this time, a 670 nm LED was used as the second exposure member, and after color toner development was performed, the entire surface of each photoconductor was irradiated with light (transparent toner was developed on the portion where the sheet does not contact). In element (K), white toner is not developed). The results are shown in Table 1.
[0210]
<Example 8>
In the experiment of Example 7, the evaluation was performed in the same manner as in Example 6 except that the second exposure member was 655 nm LD, writing was performed only on the colored toner non-development portion of the paper width, and the image was output (paper contact). No writing is performed on the surface of the photosensitive member that is not to be printed (the transparent toner and the white toner are not developed on the portion where the sheet does not contact in any of the image forming elements). The results are shown in Table 1.
[0211]
<Example 9>
In the experiment of Example 5, the document size was changed from A4 to B5 (the image was reduced to 87%, and the same image as FIG. 12 was stored in B5), and the longitudinal direction of the paper was aligned with the longitudinal direction of the photoconductor. Output was done. At this time, a 670 nm LED was used as the second exposure member, and after color toner development was performed, the entire surface of each photoconductor was irradiated with light (transparent toner was developed on the portion where the sheet does not contact). In element (K), white toner is not developed). The results are shown in Table 1.
[0212]
<Example 10>
In the experiment of Example 8, the evaluation was performed in the same manner as in Example 8 except that the second exposure member was 655 nm LD, writing was performed only on the colored toner non-development portion of the paper width, and the image was output (paper contact). No writing is performed on the surface of the photosensitive member that is not to be printed (the transparent toner and the white toner are not developed on the portion where the sheet does not contact in any of the image forming elements). The results are shown in Table 1.
[0213]
<Example 11>
In the experiment of Example 5, evaluation was performed in the same manner as in Example 5 except that the photoconductors mounted on all the image forming element cartridges were changed to the photoconductors 5. The results are shown in Table 1.
[0214]
<Example 12>
In the experiment of Example 5, the evaluation was performed in the same manner as in Example 5 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 6. The results are shown in Table 1.
[0215]
<Example 13>
In the experiment of Example 5, the evaluation was performed in the same manner as in Example 5 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 7. The results are shown in Table 1.
[0216]
<Example 14>
In the experiment of Example 5, evaluation was performed in the same manner as in Example 5 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 8. The results are shown in Table 1.
[0217]
<Example 15>
In the experiment of Example 5, evaluation was performed in the same manner as in Example 5 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 9. The results are shown in Table 1.
[0218]
<Example 16>
In the experiment of Example 5, evaluation was performed in the same manner as in Example 5 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 10. The results are shown in Table 1.
[0219]
<Example 17>
In the experiment of Example 5, the experiment was performed in the same manner as in Example 5 except that the gap of the non-contact charging roller was changed to 150 μm. The results are shown in Table 1.
[0220]
<Example 18>
In the experiment of Example 5, the experiment was performed in the same manner as in Example 5 except that the gap of the non-contact charging roller was changed to 250 μm. The results are shown in Table 1.
[0221]
<Example 19>
In the experiment of Example 5, the experiment was performed in the same manner as in Example 5 except that the gap of the charging roller was changed to 0 μm (in a contact state). The results are shown in Table 1.
[0222]
<Comparative Example 10>
In the experiment of Example 19, the experiment was performed in the same manner as in Example 19 except that the charging conditions of the charging roller were changed as follows. The results are shown in Table 1.
Charging conditions:
AC bias: None
DC bias: −1500 V (adjusted so that the surface potential of the unexposed portion of the photoreceptor is −600 V)
[0223]
<Comparative Example 11>
In the experiment of Example 5, the experiment was performed in the same manner as in Example 5 except that the charging roller was changed to a scorotron charger and changed to the following charging conditions. The results are shown in Table 1.
Charging conditions:
Applied voltage: -6.2 kV
Grid potential: -600V
The white solid images in Table 1 were evaluated for stains on the background (stains) according to the following criteria.
[0224]
<Soil dirt rank>
5: Almost no dirt, 4: Slightly
3: Actual use limit level, 2 or less: Level that cannot withstand actual use
The film thickness in Table 1 represents the amount of wear per 10,000 revolutions of the photoreceptor (typically, the value of the photoreceptor used at the magenta station is shown). For the photoconductor used in the examples, measurement was made every 10 mm in the longitudinal direction of the photoconductor, and an arithmetic average was obtained. On the other hand, since the photoconductor used in the comparative example has a region that is partially worn, the portion of the photoconductor (the central portion of the photoconductor) that is almost uniformly worn except for the partially worn portion. Arithmetic average was obtained.
The film thickness uniformity indicates a film thickness profile in the longitudinal direction, and shows how the profile is changed by the running test in comparison with the uniform wear portion. If the situation differs between the four photoconductors, the characteristics are shown for each photoconductor.
[0225]
[Table 1]

[0226]
[Table 2]

[0227]
<Example 20>
The photoconductor 11 was set in the cartridge shown in FIG. 7A, and three image forming elements (M, C, K) were prepared. Further, the photoreceptor 1 was set in the cartridge shown in FIG. 7B, and one image forming element (Y) was prepared. These image forming element cartridges were mounted on the image forming apparatus shown in FIG. K-1, Y-1, M-1, and C-1 developers are added to the colored toner developing portions of each image forming element, and T-1 developer is supplied to all the transparent toner developing portions. did. Further, the developer of W-1 was charged into the white toner developing portion mounted on the image forming element (Y) (both of them were negatively charged and reversely developed in the image light writing portion). As the charging member, a non-contact charging roller as shown in FIG. 6 (the gap between the roller surface and the photoreceptor surface in the image forming area is 50 μm) is used. (DC bias: -600 V, AC bias: 2.0 kV (peak to peak), frequency: 1.2 kHz). As an exposure light source (first writing light) for forming a colored toner image, writing was performed at a writing density of 600 dpi using an LD of 780 nm (beam diameter of 50 μm on the surface of the photoreceptor) (the irradiation energy at the solid portion is 4.0 erg). In the M, C, and K image forming elements, a 670 nm LED was used as the second exposure light source, and after color toner development, the entire surface of each photoconductor was irradiated with light to develop transparent toner. In the Y image forming element, a 780 nm LD is used as the second exposure light source, and after developing the colored toner, writing is performed only on the developed portion of the M, C, K colored toner, and the transparent toner is developed. Further, using a 670 nm LED as a third exposure light source, the entire surface of the photoreceptor was irradiated with light to develop white toner. All developments were performed in a non-contact manner. A scorotron charger was used as the transfer charging member, and the transfer current was controlled to 35 μA. A blade made of urethane rubber was used as the cleaning member.
[0228]
Under the above conditions, the A4 original shown in FIG. 12 was output 100,000 images in the direction in which the longitudinal direction of the paper and the longitudinal direction of the photosensitive member are aligned. Images after the fifth and 100,000th sheet were evaluated. Further, after outputting 100,000 sheets, a white solid image was output for each of Y, M, C, and K, each halftone image. All of the above image evaluations were performed on A4 paper (aligned with the longitudinal direction of the photoreceptor and the longitudinal direction of the paper). Further, the photoconductor was taken out from the cartridge, and the film thickness distribution in the longitudinal direction of the photoconductor was measured. The results are shown in Table 2.
[0229]
<Example 21>
In the experiment of Example 20, K-2, Y-2, M-2, C-2, T-2, and W-2 were used as the color toner developer, the transparent toner developer, and the white toner developer. Evaluation was performed in the same manner as in Example 20 except that. The results are shown in Table 2.
[0230]
<Example 22>
In the experiment of Example 20, K-3, Y-3, M-3, C-3, T-2, and W-3 were used as the color toner developer, the transparent toner developer, and the white toner developer. Except for this, the evaluation was performed in the same manner as in Example 20. The results are shown in Table 2.
[0231]
<Comparative Example 12>
In the experiment of Example 20, evaluation was performed in the same manner as in Example 20 except that the second exposure member, the transparent toner developing member, the third exposure member, and the white toner developing member were removed from the image forming apparatus and image formation was performed. Went. The results are shown in Table 2.
[0232]
<Comparative Example 13>
In the experiment of Example 21, evaluation was performed in the same manner as in Example 21 except that the second exposure member, the transparent toner developing member, the third exposure member, and the white toner developing member were removed from the image forming apparatus and image formation was performed. Went. The results are shown in Table 2.
[0233]
<Comparative example 14>
In the experiment of Example 22, evaluation was performed in the same manner as in Example 22 except that the second exposure member, the transparent toner developing member, the third exposure member, and the white toner developing member were removed from the image forming apparatus and image formation was performed. Went. The results are shown in Table 2.
[0234]
<Comparative Example 15>
In the experiment of Example 20, evaluation was performed in the same manner as in Example 20 except that the third exposure member and the white toner developing member were removed from the image forming apparatus and image formation was performed. The results are shown in Table 2.
[0235]
<Comparative Example 16>
In the experiment of Example 21, evaluation was performed in the same manner as in Example 21 except that the third exposure member and the white toner developing member were removed from the image forming apparatus and image formation was performed. The results are shown in Table 2.
[0236]
<Comparative Example 7>
In the experiment of Example 22, evaluation was performed in the same manner as in Example 22 except that the third exposure member and the white toner developing member were removed from the image forming apparatus and image formation was performed. The results are shown in Table 2.
[0237]
<Example 23>
In the experiment of Example 22, the evaluation was performed in the same manner as in Example 22 except that the second exposure member mounted on all the image forming elements was set to 780 nm LD and writing was performed only on the transparent toner image forming unit. The results are shown in Table 2.
[0238]
<Example 24>
In the experiment of Example 22, as a colored toner developer, a transparent toner developer, and a white toner developer, K-4, Y-4, M-4, C-4, T-4, and W-4 were used. Evaluation was performed in the same manner as in Example 22 except that the third exposure member was removed from the forming element (K) (configuration shown in FIGS. 1 and 7-c) and white toner was developed by regular development. The results are shown in Table 2.
[0239]
<Example 25>
In the experiment of Example 23, evaluation was performed in the same manner as in Example 23 except that the photoconductors mounted on all the image forming element cartridges were changed to the photoconductor 12. The results are shown in Table 2.
[0240]
<Example 26>
In the experiment of Example 23, evaluation was performed in the same manner as in Example 23 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 13. The results are shown in Table 2.
[0241]
<Example 27>
In the experiment of Example 23, evaluation was performed in the same manner as in Example 23 except that the photoconductor mounted on all the image forming element cartridges was changed to the photoconductor 14. The results are shown in Table 2.
The white solid images in Table 2 were evaluated for stains on the background (stains) according to the following criteria.
[0242]
<Soil dirt rank>
5: Almost no dirt, 4: Slightly
3: Actual use limit level, 2 or less: Level that cannot withstand actual use
The film thickness in Table 2 represents the amount of wear per 10,000 revolutions of the photoreceptor (representing the value of the photoreceptor used in the magenta station as a representative example). For the photoconductor used in the examples, measurement was made every 10 mm in the longitudinal direction of the photoconductor, and an arithmetic average was obtained. On the other hand, since the photoconductor used in the comparative example has a region that is partially worn, the portion of the photoconductor (the central portion of the photoconductor) that is almost uniformly worn except for the partially worn portion. Arithmetic average was obtained.
[0243]
The film thickness uniformity in Table 2 indicates the film thickness profile in the longitudinal direction, and shows how the profile has been changed by the running test in comparison with the uniform worn portion. If the situation differs between the four photoconductors, the characteristics are shown for each photoconductor.
[0244]
[Table 3]

[0245]
【The invention's effect】
As described above, as is clear from the detailed and specific description, according to the present invention, even when outputting a wide variety of originals, partial deterioration of the photoconductor is prevented, and the color reproducibility is high durability and repeated use. Therefore, a high-speed full-color electrophotographic apparatus capable of forming a stable image that is favorable and that is free from background stains is provided.
[Brief description of the drawings]
FIG. 1 is a schematic view for explaining a full-color image forming apparatus of the present invention.
FIG. 2 is a cross-sectional view showing another configuration example of the full-color image forming apparatus of the present invention.
FIG. 3 is a diagram illustrating a feeding direction of transfer paper with respect to a photosensitive member.
FIG. 4 is a diagram illustrating a longitudinal relationship between a photoconductor and transfer paper.
FIG. 5 is a diagram illustrating a state of a toner layer transferred on a transfer paper.
FIG. 6 is a schematic diagram showing a proximity charging mechanism (a gap forming member is on the charging member side).
FIG. 7 is a schematic diagram illustrating an example of a process cartridge.
(A) is an image forming element process cartridge having no white toner developing member.
(B) is an image forming element process cartridge having a white toner developing member.
(When writing is used for white toner development)
(C) is an image forming element process cartridge having a white toner developing member.
(When writing is not used for white toner development)
FIG. 8 is a cross-sectional view showing an electrophotographic photosensitive member of the present invention.
FIG. 9 is an X-ray diffraction spectrum of titanyl phthalocyanine A.
FIG. 10 is an X-ray diffraction spectrum of titanyl phthalocyanine B.
FIG. 11 is an X-ray diffraction spectrum of titanyl phthalocyanine C.
FIG. 12 is a diagram illustrating a document used in an example.
[Explanation of symbols]
1C, 1M, 1Y, 1K ··· Photoconductor
2C, 2M, 2Y, 2K, ... Charging member
3C, 3M, 3Y, 3K ... Laser light
4C, 4M, 4Y, 4K... Colored toner developing member
5C, 5M, 5Y, 5K... Developing member for transparent toner
6C, 6M, 6Y, 6K ... Cleaning member
7C, 7M, 7Y, 7K ... Transfer charging member
8 ・ ・ ・ ・ Intermediate transfer belt
9 ・ ・ ・ ・ Registration roller
10: Fixing device
11C, 11M, 11Y, 11K... Image forming element
12 ・ ・ ・ Transfer paper
13Y ... White toner developing member
14C, 14M, 14Y, 14K, ... second exposure member
15Y ... Third exposure member
16: Transfer conveying member
17... Drive or driven roller of transfer conveying member
101: Photoconductor
102 ... Flange
103 ・ ・ ・ Transfer paper
K: Black toner
C ... Cyan toner
M: Magenta toner
Y ... Yellow toner
T: Transparent toner
W ... White toner
1 ... Photoconductor
2 ... Charging member
21 ... Gap forming member
22 ... Metal shaft
23... Image forming area
24 ... Non-image forming area
201 ・ ・ ・ Photoconductor
202 ・ ・ ・ Charging member
203... Colored toner writing member
204... Developing member for colored toner
205 ... Second exposure member
206... Developing member for transparent toner
207... Cleaning member
208... White toner developing member
209... Third exposure member
31 ... Conductive support
35 ・ ・ ・ Charge generation layer
37 ・ ・ ・ Charge transport layer
39 ... Surface protective layer

Claims (28)

At least a charging member for charging the photosensitive member by applying a voltage in which an alternating current component is superimposed on a direct current component to the charging member, an image exposing unit, a developing unit, a transferring unit, a cleaning unit, and a photosensitive member for 10,000 rotations in image formation. A full-color image forming apparatus in which a plurality of image forming elements comprising an electrophotographic photosensitive member provided with a surface protective layer having an abrasion resistance of 0.1 μm or less is arranged, and the color in each image forming element Between the image exposure means and the transfer means used for toner image formation, there is provided a colored toner developing means for developing based on the image exposure, and a developing means for developing a non-image forming area of the colored toner with a transparent toner. Among the plurality of image forming elements, the colored toner developing unit in the image forming element that first performs toner transfer to the intermediate transfer member; During the shooting means, the full-color image forming apparatus characterized by comprising a developing means for developing a white toner. A second image exposure unit is provided between the colored toner developing unit and the transparent toner developing unit in the image forming element, and the transparent toner is developed by performing image exposure on a non-image forming region of the colored toner. The full-color image forming apparatus according to claim 1. 3. The full-color image forming apparatus according to claim 2, wherein at least the second image exposure unit writes an electrostatic latent image on the photosensitive member by a semiconductor laser (LD) or a light emitting diode (LED). The full-color image forming apparatus according to claim 1, wherein the development of the transparent toner is performed in a non-contact state. 5. The full-color image forming apparatus according to claim 1, wherein in the image forming element having the white toner developing means, the white toner is developed in the non-image forming area of the colored toner in all the image forming elements. A third image exposing unit is provided between the colored toner developing unit and the white toner developing unit in the image forming element having the white toner developing unit, and the entire surface of the photoconductor is irradiated with light, and then development with the white toner is performed. The full-color image forming apparatus according to claim 5, wherein the full-color image forming apparatus is performed. In the full-color image forming apparatus, a third image exposure unit is provided between the color toner development unit and the white toner development unit in the image forming element having the white toner development unit, and writing by the third image exposure unit is performed. The full-color image forming apparatus according to claim 5, wherein the color toner image and the transparent toner image are not exposed. 8. The full-color image forming apparatus according to claim 6, wherein at least the third image exposure unit writes an electrostatic latent image on the photosensitive member with an LD or an LED. 6. The full-color image forming apparatus according to claim 1, wherein the charging polarity of the white toner is opposite to that of the colored toner and the transparent toner. The full-color image forming apparatus according to claim 5, wherein the development of the white toner is performed in a non-contact state. The image exposure means used for forming the color toner image writes an electrostatic latent image on the photoconductor with an LD or an LED, and the longitudinal direction of the output paper is the longitudinal direction of the photoconductor regardless of the orientation of the input document. The full-color image forming apparatus according to claim 1, wherein the image is output in a direction aligned. In the image forming apparatus, the transparent toner is developed outside the range of the output paper even when the length of the output paper in the longitudinal direction is shorter than the length of the effective image forming area in the longitudinal direction of the photosensitive member. The full-color image forming apparatus according to claim 11. The image forming apparatus according to claim 1, wherein the charging unit includes a charging member disposed in a non-contact proximity to the photosensitive member. The image forming apparatus according to claim 13, wherein a gap between the charging member and the photosensitive member is 200 μm or less. 15. The colored toner, the transparent toner, and the white toner used for the image forming element each contain a wax, and the content of the wax contained in both is substantially the same. The full-color image forming apparatus according to any one of the above. 15. The color toner, the transparent toner, and the white toner used for the image forming element each contain a lubricant, and the amount of lubricant contained in both is substantially the same. The full-color image forming apparatus described. The full-color image forming apparatus according to claim 16, wherein the lubricant is zinc stearate. 15. The color toner, the transparent toner, and the white toner used for the image forming element each contain a fluidizing agent, and the amount of fluidizing agent contained in both is substantially the same. The full-color image forming apparatus according to any one of the above. The full-color image forming apparatus according to any one of claims 1 to 18, wherein the protective layer of the electrophotographic photosensitive member contains an inorganic pigment or a metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more. The full-color image forming apparatus according to claim 19, wherein the metal oxide is any one of alumina, titanium oxide, and silica having a specific resistance of 10 ¹⁰ Ω · cm or more. The full-color image forming apparatus according to claim 20, wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more. The full-color image forming apparatus according to claim 19, wherein the protective layer contains a polymer charge transport material. 23. The full-color image forming apparatus according to claim 1, wherein the charge generating material contained in the electrophotographic photosensitive member is an azo pigment represented by the following formula (XI).

In the formula, Cp ₁ and Cp ₂ represent coupler residues. R ₂₀₁ and R ₂₀₂ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a cyano group, and may be the same or different. Cp ₁ and Cp ₂ are represented by the following (XII),

In formula (XII), R ₂₀₃ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group. R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ are each a hydrogen atom, a nitro group, a cyano group, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. Represents an alkoxy group, a dialkylamino group, or a hydroxyl group, and Z represents an atomic group necessary for constituting a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. The full-color image forming apparatus according to claim 23, wherein Cp ₁ and Cp ₂ of the azo pigment are different from each other. The charge generating material contained in the electrophotographic photosensitive member has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. The full-color image forming apparatus according to any one of claims 1 to 22, wherein the full-color image forming apparatus is a titanyl phthalocyanine containing The titanyl phthalocyanine has a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-rays (wavelength 1.542 mm), and is further dominant at 9.4 °, 9.6 °, and 24.0 °. It has a peak and has a peak at 7.3 ° as the lowest diffraction peak, no peak between the 7.3 ° peak and the 9.4 ° peak, and 26.3 26. The full-color image forming apparatus according to claim 25, wherein there is no peak at. 27. The full-color image forming apparatus according to any one of claims 1 to 26, wherein a surface of a conductive support of the electrophotographic photosensitive member is anodized. 2. The full color image forming apparatus according to claim 1, wherein at least the photosensitive member is in the form of a cartridge housed in one unit together with one means selected from charging means, exposure means, and cleaning means. 27. The full-color image forming apparatus according to any one of 27.

Images