JP2004287107A - Heat developable photosensitive material and image forming method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material for a photomechanical process having small temperature and humidity dependence of maximum density (Dmax) in development. <P>SOLUTION: In a heat developable photosensitive material comprising on a support photograph constituting layers including an image forming layer containing a photosensitive silver halide, a non-photosensitive organic silver salt and a reducing agent, a compound having water vapor permeability of ≤100 g/m<SP>2</SP>×24 h measured according to the description of JIS Z0208 is contained in at least one of the photograph constituting layers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４０】
式中、Ｒは水素原子、又は炭素原子数１〜１０のアルキル基（例えば、−Ｃ_４Ｈ_９、２，４，４−トリメチルペンチル）を表し、Ｒ′及びＲ″は炭素原子数１〜５のアルキル基（例えば、メチル、エチル、ｔ−ブチル）を表す。
【００４１】
一般式（Ａ）で表される化合物の具体例を以下に示す。ただし、本発明は、以下の化合物に限定されるものではない。
【００４２】
【化２】

【００４３】
前記一般式（Ａ）で表される化合物を始めとする還元剤の使用量は、好ましくは銀１モル当り１×１０^−２〜１０モル、特に１×１０^−２〜１．５モルである。
【００４４】
本発明の熱現像感光材料において、上述した各成分と共に色調剤、色調付与剤若しくは賦活剤トーナーと称せられる添加剤（以下、色調剤と呼ぶ）が使用される事が望ましい。色調剤は有機銀塩と還元剤の酸化還元反応に関与して、生ずる銀画像を濃色、特に黒色にする機能を有する。好適な色調剤の例は、ＲＤ１７０２９号に開示されており、好ましい色調剤としてはフタラゾン又はフタラジンが挙げられる。
【００４５】
本発明の熱現像感光材料には、例えば特開昭６３−１５９８４１号、同６０−１４０３３５号、同６３−２３１４３７号、同６３−２５９６５１号、同６３−３０４２４２号、同６３−１５２４５号の各公報、米国特許第４，６３９，４１４号、同４，７４０，４５５号、同４，７４１，９６６号、同４，７５１，１７５号、同４，８３５，０９６号の各明細書に記載された増感色素が使用できる。有用な増感色素は、例えばＲＤ１７６４３ＩＶ−Ａ項（１９７８年１２月ｐ．２３）、同Ｉｔｅｍ１８３１Ｘ項（１９７８年８月ｐ．４３７）に記載もしくは引用された文献に記載されている。特に各種スキャナー光源の分光特性に適した分光感度を有する増感色素を有利に選択することができる。例えば、特開平９−３４０７８号、同９−５４４０９号、同９−８０６７９号の各公報記載の化合物が好ましく用いられる。
【００４６】
強色増感されている場合、光感度が特に高くなるので、還元剤の失活をさせない場合、現像後のプリントアウト銀は、大きくなりやすく本発明には特に有効である。又、赤外増感されている場合には、更に赤外増感色素はハロゲン化銀や、有機銀塩を幾分かは還元できる酸化還元電位を有しているため、暗所においても前述の有機銀塩を還元できる還元剤の存在下では、カブリ銀となる銀クラスターを生成しやすい。生成した銀クラスターは又、触媒核となって、カブリを誘起したりするため、暗所において保存したとき保存性が低下したり、又、現像後に明所においた時、プリントアウト銀が大きくなる等の現象が起こる。更に赤外線感光材料は、可視光の範囲外の熱輻射線領域まで感度がのびている為、暗所においても熱輻射線によるプリントアウト銀が多くなったりすることに対し効果がある。特に、強色増感剤により感度が高められた、赤外分光増感された熱現像感光材料の場合には効果が大きい。
【００４７】
これらの増感色素は単独に用いてもよいが、それらの組合せを用いてもよく、増感色素の組合せは、特に強色増感の目的でしばしば用いられる。増感色素とともに、それ自身分光増感作用をもたない色素あるいは可視光を実質的に吸収しない物質であって、強色増感を示す物質を乳剤中に含んでもよい。有用な増感色素、強色増感を示す色素の組合せおよび強色増感を示す物質は、ＲＤ１７６４３（１９７８年１２月発行）第２３頁ＩＶのＪ項、あるいは特公平９−２５５００号、同４３−４９３３号、特開昭５９−１９０３２号、同５９−１９２２４２号、特開平５−３４１４３２号等の各公報に記載されている。
【００４８】
強色増感剤としては、下記一般式で表される複素芳香環メルカプト化合物が好ましい。
【００４９】
一般式 Ａｒ−ＳＭ
式中、Ｍは水素原子またはアルカリ金属原子であり、Ａｒは１個以上の窒素、硫黄、酸素、セレニウムまたはテルリウム原子を有する複素芳香環である。好ましくは、ベンズイミダゾール、ナフトイミダゾール、ベンゾチアゾール、ナフトチアゾール、ベンズオキサゾール、ナフトオキサゾール、ベンゾセレナゾール、ベンゾテトラゾール、イミダゾール、オキサゾール、ピラゾール、トリアゾール、トリアジン、ピリミジン、ピリダジン、ピラジン、ピリジン、プリン、キノリンまたはキナゾリンである。
【００５０】
なお、有機銀塩及び／又は感光性ハロゲン化銀粒子乳剤の分散物中に含有させたときに、実質的に上記のメルカプト化合物を生成するジスルフィド化合物も、含まれる。特に、下記の一般式で表せるジスルフィド化合物が、好ましい例として挙げることができる。
【００５１】
一般式 Ａｒ−Ｓ−Ｓ−Ａｒ
式中のＡｒは、Ａｒ−ＳＭの場合と同義である。
【００５２】
上記の複素芳香環は、例えばハロゲン原子（例えば、Ｃｌ、Ｂｒ、Ｉ）、ヒドロキシル基、アミノ基、カルボキシル基、アルキル基（例えば、１個以上の炭素原子、好ましくは１〜４個の炭素原子を有するもの）及びアルコキシ基（例えば、１個以上の炭素原子、好ましくは１〜４個の炭素原子を有するもの）からなる群から選ばれる置換基を有しうる。
【００５３】
強色増感剤は有機銀塩及びハロゲン化銀粒子を含む乳剤層中に、銀１モル当たり０．００１〜１．０モルの範囲で用いるのが好ましい。特に好ましくは、銀１モル当たり０．０１〜０．５モルの範囲の量が好ましい。
【００５４】
本発明の熱現像感光材料中にはカブリ防止剤が含まれてよい。有効なカブリ防止剤として、例えば米国特許第３，５８９，９０３号明細書などで知られている水銀化合物は環境的に好ましくない。そのため非水銀カブリ防止剤の検討が古くから行われてきた。非水銀カブリ防止剤としては、例えば米国特許第４，５４６，０７５号及び同４，４５２，８８５号の各明細書及び特開昭５９−５７２３４号公報に開示されている様なカブリ防止剤が好ましい。
【００５５】
本発明において、経時保存での濃度変動を更によくするには、現像後のカブリを低減する酸化剤を用いることである。このような酸化剤として好ましくは、例えば特開昭５０−１１９６２４号、同５０−１２０３２８号、同５１−１２１３３２号、同５４−５８０２２号、同５６−７０５４３号、同５６−９９３３５号、同５９−９０８４２号、同６１−１２９６４２号、同６２−１２９８４５号、特開平６−２０８１９１号、同７−５６２１号、同７−２７８１号、同８−１５８０９号の各公報、米国特許第５，３４０，７１２号、同５，３６９，０００号、同５，４６４，７３７号、同３，８７４，９４６号、同４，７５６，９９９号、同５，３４０，７１２号の各明細書、欧州特許第６０５，９８１Ａ１号、同６２２，６６６Ａ１号、同６３１，１７６Ａ１号の各明細書、特公昭５４−１６５号公報、特開平７−２７８１号公報、米国特許第４，１８０，６６５号及び同４，４４２，２０２号の各明細書に記載されている化合物等を用いることができるが、好ましくは特開２０００−１３１７９５号公報に記載されているポリハロゲン化合物である。
【００５６】
酸化剤は、１０ｍｇ／ｍ^２〜３ｇ／ｍ^２含有することが好ましく、５０ｍｇ／ｍ^２〜１ｇ／ｍ^２がより好ましい。酸化剤は溶液、粉末、固体微粒子分散物などいかなる方法で添加してもよく、特に感光層に、固体微粒子分散されていることが好ましい。分散の際に分散助剤を用いてもよい。また、増感色素、還元剤、色調剤など他の添加剤と混合した溶液として添加してもよい。
【００５７】
上記の酸化剤以外にも、好適なカブリ防止剤としては、米国特許第３，８７４，９４６号明細書及び同第４，７５６，９９９号明細書に開示されているような化合物、特開平９−２８８３２８号公報段落番号〔００３０〕〜〔００３６〕に記載されている化合物、特開平９−９０５５０号公報段落番号〔００６２〕〜〔００６３〕に記載されている化合物、米国特許第５，０２８，５２３号明細書及び欧州特許第６００，５８７号、同６３１，１７６号、同６０５，９８１号の各明細書に開示されている化合物などが好ましく用いられる。
【００５８】
感光層にポリマーラテックスを用いる場合は、感光層は水系の塗布液を塗布後乾燥して調製することが好ましい。ただし、ここで言う「水系」とは、塗布液の溶媒（分散媒）の５０質量％以上が水であることをいい、好ましくは溶媒の６５質量％以上が水である。塗布液の水以外の成分は、メチルアルコール、エチルアルコール、イソプロピルアルコール、メチルセルソルブ、エチルセルソルブ、ジメチルホルムアミド、酢酸エチルなどの水混和性の有機溶媒を用いることができる。具体的な溶媒組成の例としては、以下のようなものがある。水／メタノール＝９０／１０、水／メタノール＝７０／３０、水／エタノール＝９０／１０、水／イソプロパノール＝９０／１０、水／ジメチルホルムアミド＝９５／５、水／メタノール／ジメチルホルムアミド＝８０／１５／５、水／メタノール／ジメチルホルムアミド＝９０／５／５（ただし数字は質量％を表す）。
【００５９】
感光層には、架橋のための架橋剤、塗布性改良のための界面活性剤などを添加してもよい。感光層にポリマーラテックスを含有する場合、熱感光層塗布液は、いわゆるチキソトロピー流体であることが好ましい。チキソトロピー性とは剪断速度の増加に伴い、粘度が低下する性質を言う。粘度測定にはいかなる装置を使用してもよいが、レオメトリックスファーイースト株式会社製ＲＦＳフルードスペクトロメーターが好ましく用いられ２５℃で測定される。本発明における有機銀塩含有流体もしくは熱画像形成層塗布液は、剪断速度０．１Ｓ−１における粘度が４００ｍＰａ・ｓ以上、１００，０００ｍＰａ・ｓ以下が好ましく、さらに好ましくは５００ｍＰａ・ｓ以上、２０，０００ｍＰａ・ｓ以下である。また、剪断速度１０００Ｓ−１においては、１ｍＰａ・ｓ以上、２００ｍＰａ・ｓ以下が好ましく、さらに好ましくは５ｍＰａ・ｓ以上、８０ｍＰａ・ｓ以下である。
【００６０】
チキソトロピー性を発現する系は、各種知られており高分子刊行会編「講座・レオロジー」、室井、森野共著「高分子ラテックス」（高分子刊行会発行）などに記載されている。流体がチキソトロピー性を発現させるには、固体微粒子を多く含有することが必要である。また、チキソトロピー性を強くするには、増粘線形高分子を含有させること、含有する固体微粒子の異方形でアスペクト比が大きくすること、アルカリ増粘、界面活性剤の使用などが有効である。
【００６１】
感光層の全バインダー量は０．２〜３０ｇ／ｍ^２、より好ましくは１〜１５ｇ／ｍ^２の範囲が好ましい。
【００６２】
また熱現像感光材料の表面を保護したり擦り傷を防止するために、感光層の外側に非感光層を有することができる。これらの非感光層に用いられるバインダーは、感光層に用いられるバインダーと同じ種類でも異なった種類でもよい。
【００６３】
本発明においては、感光層側にマット剤を含有することが好ましく、熱現像後の画像の傷つき防止のためには、熱現像感光材料の表面にマット剤を配することが好ましく、そのマット剤を感光層側の全バインダーに対し、質量比で０．５〜３０％含有することが好ましい。また、支持体をはさみ感光層の反対側に非感光層を設ける場合は、非感光層側の少なくとも１層中にマット剤を含有することが好ましく、マット剤の形状は、定形、不定形どちらでもよいが、好ましくは定形で、球形が好ましく用いられる。
【００６４】
本発明の熱現像感光材料は、支持体上に感光層のみを形成してもよいが、感光層の上に少なくとも１層の非感光層を形成することが好ましい。感光層に通過する光の量又は波長分布を制御するために、感光層と同じ側にフィルター染料層および／又は反対側にアンチハレーション染料層、いわゆるバッキング層を形成してもよいし、感光層に染料又は顔料を含ませてもよい。
【００６５】
またこれらの非感光層には、前記のバインダーやマット剤を含有することが好ましく、さらにポリシロキサン化合物やワックスや流動パラフィンのようなスベリ剤を含有してもよい。
【００６６】
また、本発明の熱現像感光材料には、塗布助剤として各種の界面活性剤を用いることができる。その中でもフッ素系界面活性剤が、帯電特性を改良したり、斑点状の塗布故障を防ぐために好ましく用いられる。
【００６７】
本発明においては、アンチハレーション層を感光層に対して光源から遠い側に設けることができる。アンチハレーション層は所望の波長範囲での最大吸収が０．１以上、２以下であることが好ましく、さらに好ましくは０．２以上、１．５以下の露光波長の吸収であり、且つ処理後の可視領域においての吸収が０．００１以上、０．２未満であることが好ましく、さらに好ましくは０．００１以上、０．１５未満の光学濃度を有する層であることが好ましい。
【００６８】
本発明でハレーション防止染料を使用する場合、こうした染料は波長範囲で目的の吸収を有し、処理後に可視領域での吸収が充分少なく、上記アンチハレーション層の好ましい吸光度スペクトルの形状が得られればいかなる化合物でもよい。
【００６９】
例えば、以下に挙げるものが開示されているが、本発明はこれに限定されるものではない。単独の染料としては、特開昭５９−５６４５８号、特開平２−２１６１４０号、同７−１３２９５号、同７−１１４３２号の各公報、米国特許第５，３８０，６３５号明細書、特開平２−６８５３９号公報第１３頁左下欄１行目から同第１４頁左下欄９行目、同３−２４５３９号公報第１４頁左下欄から同第１６頁右下欄記載の化合物があり、処理で消色する染料としては、特開昭５２−１３９１３６号、同５３−１３２３３４号、同５６−５０１４８０号、同５７−１６０６０号、同５７−６８８３１号、同５７−１０１８３５号、同５９−１８２４３６号、特開平７−３６１４５号、同７−１９９４０９号、特公昭４８−３３６９２号、同５０−１６６４８号、特公平２−４１７３４号の各公報、米国特許第４，０８８，４９７号、同４，２８３，４８７号、同４，５４８，８９６号、同５，１８７，０４９号の各明細書などに記載されている。
【００７０】
本発明における熱現像感光材料は、支持体の一方の側に少なくとも１層の感光層を有し、他方の側にバック層を有する、いわゆる片面感光材料であることが好ましい。
【００７１】
本発明においては、バック層の好適なバインダーは透明または半透明で、一般に無色であり、天然ポリマー合成樹脂やポリマーおよびコポリマー、その他フィルムを形成する媒体、例えば：ゼラチン、アラビアゴム、ポリ（ビニルアルコール）、ヒドロキシエチルセルロース、セルロースアセテート、セルロースアセテートブチレート、ポリ（ビニルピロリドン）、カゼイン、デンプン、ポリ（アクリル酸）、ポリ（メチルメタクリル酸）、ポリ（塩化ビニル）、ポリ（メタクリル酸）、コポリ（スチレン−無水マレイン酸）、コポリ（スチレン−アクリロニトリル）、コポリ（スチレン−ブタジエン）、ポリ（ビニルアセタール）類（例えば、ポリ（ビニルホルマール）およびポリ（ビニルブチラール））、ポリ（エステル）類、ポリ（ウレタン）類、フェノキシ樹脂、ポリ（塩化ビニリデン）、ポリ（エポキシド）類、ポリ（カーボネート）類、ポリ（ビニルアセテート）、セルロースエステル類、ポリ（アミド）類がある。バインダーは水もしくは有機溶媒またはエマルジョンから被覆形成してもよい。
【００７２】
バック層は、所望の波長範囲での最大吸収が０．３以上、２以下であることが好ましく、さらに好ましくは０．５以上、２以下の吸収であり、且つ処理後の可視領域においての吸収が、０．００１以上、０．５未満であることが好ましく、さらに好ましくは０．００１以上、０．３未満の光学濃度を有する層であることが好ましい。印刷製版用に用いる場合は、４００ｎｍでの吸収が０．００１以上、０．２未満であることが好ましく、さらに好ましくは０．００１以上、０．１５未満の光学濃度を有する層であることが特に好ましい。バック層に用いるハレーション防止染料の例としては、前述のアンチハレーション層と同じである。
【００７３】
各種の添加剤は、感光層、非感光層、又はその他の形成層のいずれに添加してもよい。本発明の熱現像感光材料には、例えば界面活性剤、酸化防止剤、安定化剤、可塑剤、紫外線吸収剤、被覆助剤等を用いてもよい。これらの添加剤及び上述したその他の添加剤は、ＲＤ１７０２９（１９７８年６月ｐ．９〜１５）に記載されている化合物を好ましく用いることができる。
【００７４】
本発明の支持体としては、プラスチックフィルム（例えばセルロースアセテートフィルム、ポリエステルフィルム、ポリエチレンテレフタレートフィルム、ポリエチレンナフタレートフィルム、ポリアミドフィルム、ポリイミドフィルム、セルローストリアセテートフィルム又はポリカーボネートフィルム等）が好ましく、本発明においては２軸延伸したポリエチレンテレフタレートフィルムが特に好ましい。支持体の厚みとしては５０〜３００μｍ程度、好ましくは７０〜１８０μｍである。
【００７５】
本発明の熱現像感光材料は、いかなる方法で現像されてもよいが、通常画像露光した熱現像感光材料を昇温して現像される。好ましい現像温度としては、１０５〜１４５℃であり、さらに好ましくは１０７〜１４０℃である。現像時間としては１〜１８０秒であり、７〜５０秒がさらに好ましく、８〜２５秒が特に好ましい。
【００７６】
本発明の熱現像感光材料は、熱現像機で熱現像されることが好ましい。熱現像感光材料は熱現像部の温度バラツキの影響を受けやすく、現像ムラが出やすい。そのため特開平９−２９７３８４号、同９−２９７３８５号、同９−２９７３８６号の各公報に開示されているようにヒートドラム方式の自動熱現像機や、ＷＯ９８／２７４５８号パンフレットに開示されているような平面搬送型の自動熱現像機が用いられる。熱現像部の前にプレヒート部を有しており、プレヒートの温度は８０〜１２０℃である自動熱現像機が好ましく用いられる。プレヒートにより現像が進み、濃度ムラが少なくなるので走査ムラにも効果的である。さらに特開平１１−１３３５７２号公報に記載されているような固定された加熱体に感光材料の一方の面に接触し、感光材料の他方の面を複数のローラーで加熱体に押さえつけながら感光材料を搬送する装置を用いて熱現像処理することも好ましい。
【００７７】
本発明の熱現像感光材料の熱現像処理に用いられる熱現像機の一構成例を図１に示す。図１は熱現像機の側面図を示したものである。図１の熱現像機は熱現像感光材料１０を平面状に矯正およびプレヒートしながら加熱部に搬入する搬入ローラー対１１（上部ローラーはシリコンゴムローラーで、下部ローラーがアルミ製のヒートローラー）と熱現像後の熱現像感光材料１０を平面状に矯正しながら加熱部から搬出する搬出ローラー対１２を有する。熱現像感光材料１０は搬入ローラー対１１から搬出ローラー対１２へと搬送される間に熱現像される。この熱現像中の熱現像感光材料１０を搬送する搬送手段は画像形成層を有する面が接触する側に複数のローラー１３が設置され、その反対側のバック面が接触する側には不織布（例えば芳香族ポリアミドやテフロン（Ｒ）から成る）等が貼り合わされた平滑面１４が設置される。熱現像感光材料１０は画像形成層を有する面に接触する複数のローラー１３の駆動により、バック面を平滑面１４の上に滑らせながら搬送される。ローラー１３の上部および平滑面１４の下部には、熱現像感光材料１０の両面から加熱されるように加熱ヒーター１５が設置される。この場合の加熱手段としては板状ヒーター等が挙げられる。ローラー１３と平滑面１４とのクリアランスは平滑面の部材により異なるが、熱現像感光材料１０が搬送できるクリアランスに適宜調整される。好ましくは０〜１ｍｍである。
【００７８】
ローラー１３の表面の材質および平滑面１４の部材は、高温耐久性があり、熱現像感光材料１０の搬送に支障がなければ何でもよいが、ローラー表面の材質はシリコンゴム、平滑面の部材は芳香族ポリアミドまたはテフロン（Ｒ）（ＰＴＦＥ）製の不織布が好ましい。加熱手段としては複数のヒーターを用い、それぞれ加熱温度を自由に設定することが好ましい。なお、加熱部は、搬入ローラー対１１を有するプレヒート部Ａと、加熱ヒーター１５を備えた熱現像加熱部Ｂとで構成されるが、熱現像処理部Ｂの上流のプレヒート部Ａは、熱現像温度よりも低く（例えば１０〜３０℃程度低く）、熱現像感光材料１０中の水分量を蒸発させるのに十分な温度および時間に設定することが望ましく、熱現像感光材料１０の支持体のガラス転移温度（Ｔｇ）よりも高い温度で、現像ムラが出ないように設定することが好ましい。プレヒート部と熱現像処理部の温度分布としては±１℃以下が好ましく、さらには±０．５℃以下が好ましい。また、熱現像処理部Ｂの下流にはガイド板１６が設置され、搬出ローラー対１２とガイド板１６とを有する徐冷部Ｃが設置される。ガイド板１６は熱伝導率の低い素材が好ましく、熱現像感光材料１０に変形が起こらないようにするために冷却は徐々に行うのが好ましく、冷却速度としては、０．５〜１０℃／秒が好ましい。
【００７９】
本発明の熱現像感光材料は、いかなる方法で露光されてもよいが、露光光源としてレーザー光が好ましい。本発明によるレーザー光としては、ガスレーザー、ＹＡＧレーザー、色素レーザー、半導体レーザーなどが好ましい。その中でも干渉縞や網点の露光ムラを防止するために、縦マルチ露光や斜めに露光することが好ましい。
【００８０】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されない。
【００８１】
実施例１
《熱現像感光材料の作製》
（下引済み写真用支持体の作製）
市販の２軸延伸熱固定済みの厚さ１２５μｍのポリエチレンテレフタレートフィルムの両面に、８Ｗ／ｍ^２・分のコロナ放電処理を施し、一方の面に下記下引塗布液ａ−１を乾燥膜厚が０．８μｍになるように塗設し乾燥させて下引層Ａ−１とし、反対側の面に下記帯電防止加工した下記下引塗布液ｂ−１を乾燥膜厚が０．８μｍになるように塗設し、乾燥させて帯電防止加工下引層Ｂ−１とした。
【００８２】
〔下引塗布液ａ−１〕
ブチルアクリレート（３０質量％）／ｔ−ブチルアクリレート（２０質量％）
／スチレン（２５質量％）／２−ヒドロキシエチルアクリレート（２５質量％）
の共重合体ラテックス液（固形分３０％） ２７０ｇ
（Ｃ−１） ０．６ｇ
ヘキサメチレン−１，６−ビス（エチレンウレア） ０．８ｇ
ポリスチレン微粒子（平均粒径３μｍ） ０．０５ｇ
コロイダルシリカ（平均粒径９０μｍ） ０．１ｇ
水で１Ｌに仕上げる

（Ｃ−１） ０．６ｇ
ヘキサメチレン−１，６−ビス（エチレンウレア） ０．８ｇ
水で１Ｌに仕上げる。
【００８３】
引き続き、下引層Ａ−１及び下引層Ｂ−１の表面上に、８Ｗ／ｍ^２・分のコロナ放電を施し、下引層Ａ−１の上には下記下引上層塗布液ａ−２を、乾燥膜厚が０．１μｍになるように下引上層Ａ−２として塗設し、下引層Ｂ−１の上には下記下引上層塗布液ｂ−２を乾燥膜厚が０．８μｍになるように、帯電防止機能を持つ下引上層Ｂ−２として塗設した。
【００８４】
〔下引上層塗布液ａ−２〕
ゼラチン ０．４ｇ／ｍ^２になる質量
（Ｃ−１） ０．２ｇ
（Ｃ−２） ０．２ｇ
（Ｃ−３） ０．１ｇ
シリカ粒子（平均粒径３μｍ） ０．１ｇ
水で１Ｌに仕上げる
〔下引上層塗布液ｂ−２〕
（Ｃ−４） ６０ｇ
（Ｃ−５）を成分とするラテックス液（固形分２０％） ８０ｇ
硫酸アンモニウム ０．５ｇ
（Ｃ−６） １２ｇ
ポリエチレングリコール（質量平均分子量６００） ６ｇ
水で１Ｌに仕上げる。
【００８５】
【化３】

【００８６】
【化４】

【００８７】
〈支持体の熱処理〉
上記の下引済み支持体の下引乾燥工程に於いて、支持体を１４０℃で加熱し、その後、徐々に冷却した。その際、１×１０^５Ｐａの張力で搬送した。
【００８８】
〈試料Ｎｏ．１０１の作製〉
（感光性乳剤Ａの調製）
〈ハロゲン化銀乳剤Ａの調製〉
水９００ｍｌ中に、イナートゼラチン７．５ｇ及び臭化カリウム１０ｍｇを溶解して、温度３５℃、ｐＨを３．０に合わせた後、硝酸銀７４ｇを含む水溶液３７０ｍｌと臭化カリウムと沃化カリウム（９８／２のモル比）を硝酸銀に対し等モル、〔Ｉｒ（ＮＯ）Ｃｌ_５〕塩を銀１モル当たり１×１０^−６モル及び塩化ロジウム塩を銀１モル当たり１×１０^−６モル含む水溶液３７０ｍｌを、１０分間かけて等速でダブルジェット法にて添加した。その後、４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラザインデンを添加し、ＮａＯＨでｐＨを５．０に調整して平均粒子サイズ０．０６μｍ、分散度４５％の〔１００〕面比率８７％の非単分散立方体沃臭化銀粒子を得た。
【００８９】
この乳剤にゼラチン凝集剤を用いて凝集沈降させ、脱塩処理後、フェノキシエタノール０．１ｇを加え、ｐＨ５．９、ｐＡｇ７．５に調整した。更に、塩化金酸、無機硫黄、二酸化チオ尿素及び２，３，４，５，６−ペンタフルオロフェニルジフェニルフォスフィンセレニドで化学増感を行い、ハロゲン化銀乳剤Ａを得た。
【００９０】
〈ベヘン酸ナトリウム溶液の調製〉
９４５ｍｌの純水に、ベヘン酸３２．４ｇ、アラキジン酸９．９ｇ、ステアリン酸５．６ｇを９０℃で溶解した。次に高速で攪拌しながら、１．５モル／Ｌの水酸化ナトリウム水溶液９８ｍｌを添加した。次に、濃硝酸０．９３ｍｌを加えた後、５５℃に冷却して３０分攪拌させてベヘン酸ナトリウム溶液を得た。
【００９１】
〈プレフォーム乳剤Ａの調製〉
上記調製したベヘン酸ナトリウム溶液に、前記ハロゲン化銀乳剤Ａを１５．１ｇ添加し、水酸化ナトリウム溶液でｐＨ８．１に調整した後に、１モル／Ｌの硝酸銀溶液１４７ｍｌを１分間かけて加え、更に１５分攪拌し、限外濾過により水溶性塩類を除去した。得られたベヘン酸銀は、長辺平均サイズ０．８μｍの針状粒子であった。分散物のフロックを形成後、水を取り除き、更に６回の水洗と水の除去を行った後、乾燥させプレフォーム乳剤Ａを調製した。
【００９２】
〈有機銀塩Ａを含有する感光性乳剤Ａの調製〉
得られたプレフォーム乳剤Ａに、ポリビニルブチラール（平均分子量３，０００）のメチルエチルケトン溶液（１７質量％）５４４ｇとトルエン１０７ｇを、徐々に添加、混合した後、４０００ｐｓｉで分散させた。分散後、電子顕微鏡写真で有機銀塩粒子を観察した結果、平均粒径は０．７μｍで、分散度６０％の非単分散有機銀塩であった。また、塗布乾燥後も同様に有機銀塩粒子を観察したところ、同じ粒子が確認できた。この乳剤２４０ｇに対して、臭化カルシウムの０．０１％メタノール溶液を４．７ｍｌ添加して感光性乳剤Ａを得た。この中のハロゲン化銀粒子を電子顕微鏡で観察したところ、０．０１μｍ以下のハロゲン化銀粒子は認められなかった。
【００９３】
（バック層面側塗布）
以下の組成のバック層塗布液１とバック保護層塗布液１を、それぞれ塗布前に準絶対濾過精度２０μｍのフィルタを用いて濾過した後、押し出しコーターで前記作製した支持体の帯電防止加工した下引上層Ｂ−２面上に、合計ウェット膜厚が３０μｍになるよう、毎分１２０ｍの速度で塗布し、６０℃で４分間乾燥を行った。
【００９４】

【００９５】
【化５】

【００９６】

（感光層面側塗布）
以下の組成の感光層塗布液Ａとその上に表面保護層塗布液１（第１表面保護層）及び表面保護層塗布液２（第２表面保護層）を、準絶対濾過精度２０μｍのフィルタを用いて濾過したのち、押し出しコーターで前記支持体の下引上層Ａ−２面上に、毎分１００ｍの速度で重層塗布した。その際、塗布銀量が１．５ｇ／ｍ^２になるように調整して塗布した。その後、試料は６５℃、１分間乾燥を行った。
【００９７】
画像形成層側の写真構成層は、下引上層Ａ−２面上に順次、感光層、第１表面保護層、第２表面保護層の順となる。
【００９８】

〔表面保護層塗布液１〕
アセトン ５ｍｌ／ｍ^２
メチルエチルケトン ２１ｍｌ／ｍ^２
セルロースアセテートブチレート ２．３ｇ／ｍ^２
メタノール ７ｍｌ／ｍ^２
フタラジン ２５０ｍｇ／ｍ^２
ビニルスルホン化合物：ＶＳ−１ ３５ｍｇ／ｍ^２
フッ素系界面活性剤：Ｃ_１２Ｆ_２５（ＣＨ_２ＣＨ_２Ｏ）_１０Ｃ_１２Ｆ_２５
１０ｍｇ／ｍ^２
【００９９】
【化６】

【０１００】
【化７】

【０１０１】

以上のようにして、比較となる熱現像感光材料を作製した。この熱現像材料を試料Ｎｏ．１０１とする。
【０１０２】
〈試料Ｎｏ．１０２の作製〉
試料Ｎｏ．１０１において、感光層塗布液Ａに、本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物である塩化ノルマルパラフィンを２００ｍｇ／ｍ^２加えた以外は、試料Ｎｏ．１０１と同様にして本発明に係る熱現像感光材料を作製した。この熱現像材料を試料Ｎｏ．１０２とする。
【０１０３】
〈試料Ｎｏ．１０３の作製〉
試料Ｎｏ．１０１において、表面保護層塗布液１に、本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物である塩化ノルマルパラフィンを２００ｍｇ／ｍ^２加えた以外は、試料Ｎｏ．１０１と同様にして本発明に係る熱現像感光材料を作製した。この熱現像材料を試料Ｎｏ．１０３とする。
【０１０４】
〈試料Ｎｏ．１０４の作製〉
試料Ｎｏ．１０１において、感光層塗布液Ａ及び表面保護層塗布液１に、本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物である塩化ノルマルパラフィンを、それぞれ１００ｍｇ／ｍ^２（合計２００ｍｇ／ｍ^２）加えた以外は、試料Ｎｏ．１０１と同様にして本発明に係る熱現像感光材料を作製した。この熱現像材料を試料Ｎｏ．１０４とする。
【０１０５】
〈試料Ｎｏ．１０５の作製〉
試料Ｎｏ．１０１において、表面保護層塗布液２に、本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物である塩化ノルマルパラフィンを１５０ｍｇ／ｍ^２加えた以外は、試料Ｎｏ．１０１と同様にして本発明に係る熱現像感光材料を作製した。この熱現像材料を試料Ｎｏ．１０５とする。
【０１０６】
《写真性能の評価》
（露光処理）
得られた熱現像感光材料（試料Ｎｏ．１０１〜試料Ｎｏ．１０５）をそれぞれ、ビーム径（ビーム強度の１／２のＦＷＨＭ）１２．５６μｍ、レーザー出力５０ｍＷ、出力波長７８３ｎｍの半導体レーザーを搭載した単チャンネル円筒内面方式のレーザー露光装置を使用し、ミラー回転数６０，０００ｒｐｍ、露光時間１．２×１０^−８秒の露光を実施した。この時のオーバーラップ係数は０．４４９にし、熱現像感光材料面上のレーザーエネルギー密度としては７５μＪ／ｃｍ^２とした。
【０１０７】
（熱現像処理）
露光済みの熱現像感光材料（試料Ｎｏ．１０１〜試料Ｎｏ．１０５）をそれぞれ、図１に示した熱現像機を用いて、熱現像処理を行った。熱現像処理部のローラー表面材質はシリコンゴム、平滑面はテフロン（Ｒ）不織布にして、搬送のラインスピードは１５０ｃｍ／ｍｉｎに設定した。プレヒート部１２．２秒（プレヒート部と熱現像処理部の駆動系は独立しており、熱現像処理部との速度差は−０．５％〜−１％に設定、各プレヒート部の金属ローラーの温度設定、時間は第１ローラー温度６７℃、２．０秒、第２ローラー温度８２℃、２．０秒、第３ローラー温度９８℃、２．０秒、第４ローラー温度温度１０７℃、２．０秒、第５ローラー温度１１５℃、２．０秒、第６ローラー温度１２０℃、２．０秒にした）、熱現像処理部１２０℃（熱現像感光材料面温度）で１７．２秒、徐冷部１３．６秒で熱現像処理を行った。なお、幅方向の温度精度は±０．５℃であった。各ローラー温度の設定は熱現像感光材料の幅（例えば幅６１ｃｍ）よりも両側それぞれ５ｃｍ長くして、その部分にも温度をかけて、温度精度が出るようにした。なお、各ローラーの両端部分は温度低下が激しいので、熱現像感光材料の幅よりも５ｃｍ長くした部分はローラー中央部よりも１〜３℃温度が高くなるように設定し、熱現像感光材料（例えば幅６１ｃｍの中で）の画像濃度が均質な仕上がりになるように留意した。
【０１０８】
（写真性能の評価）
現像湿度依存性については、２５℃、８０％相対湿度の環境で１６時間放置した熱現像感光材料にその環境下で上記露光で５０μｍの線幅露光を行って、熱現像処理した場合それと同一露光条件で２０℃、１０％相対湿度環境下で１６時間放置した熱現像感光材料にその環境下で露光、熱現像処理した場合の線幅の差で評価した。また、それぞれの環境下での画像のＤｍｉｎ（カブリ）、Ｄｍａｘ（最高濃度）についても評価し、濃度測定はマクベスＴＤ９０４濃度計（可視濃度）により行った。結果を表１に示す。なお、表１において、本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物を、便宜上、低透湿性化合物と略した。
【０１０９】
【表１】

【０１１０】
表１の結果から明らかなように、本発明の熱現像感光材料である試料Ｎｏ．１０２〜試料Ｎｏ．１０５は、現像時の湿度が変化しても最高濃度（Ｄｍａｘ）の変動が小さくなっていることが判る。
【０１１１】
実施例２
本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物を、スチレン・ブタジエン共重合体に変更した以外は実施例１における試料Ｎｏ．１０２〜試料Ｎｏ．１０５と同じようにして、それぞれ試料Ｎｏ．２０２〜試料Ｎｏ．２０５を作製した。実施例１と同様にして写真性能を評価した結果、実施例１と同様の結果が得られた。
【０１１２】
実施例３
本発明に係る透湿性が１００ｇ／ｍ^２・２４ｈｒｓ以下の化合物を、塩化ビニリデンに変更する以外は実施例１における試料Ｎｏ．１０２〜試料Ｎｏ．１０５と同じようにして、それぞれ試料Ｎｏ．３０２〜試料Ｎｏ．３０５を作製した。実施例１と同様にして写真性能を評価した結果、実施例１と同様の結果が得られた。
【０１１３】
【発明の効果】
本発明により、最高濃度（Ｄｍａｘ）の現像時の温湿度依存性の小さい写真製版用熱現像感光材料熱現像感光材料を提供することができた。
【図面の簡単な説明】
【図１】本発明の熱現像感光材料の熱現像処理に用いられる熱現像機の一構成例を示す側面図である。
【符号の説明】
１０ 熱現像画像形成材料
１１ 搬入ローラー対
１２ 搬出ローラー対
１３ ローラー
１４ 平滑面
１５ 加熱ヒーター
１６ ガイド板
Ａ プレヒート部
Ｂ 熱現像処理部
Ｃ 徐冷部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photothermographic material and a method for forming an image thereof, and more particularly to a photothermographic material for a scanner and an image setter suitable for photolithography, and more specifically, a photolithography having a small humidity dependency during development processing. The present invention relates to a photothermographic material for use.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there has been a strong demand in the printing field to reduce the amount of processing waste liquid from the viewpoint of environmental protection and space saving. There is a demand for a photosensitive material that does not go through conventional processes such as development, fixing, and washing with water. In order to meet such demands, image recording materials by thermal development have been developed.
[0003]
Methods of forming an image by thermal development are described in, for example, U.S. Pat. Nos. 3,152,904 and 3,457,075, and D.C. "Thermally Processed SilverSystems A" by Klosterboer (Imaging Processes and Materials, Nebulette, 8th ed., J. Sturge, J. Sturge) Warworth, edited by A. Shepp, Chapter 9, p. 279, 1989). Such a photothermographic material includes a reducible non-photosensitive silver source (eg, a non-photosensitive organic silver salt), a catalytically active amount of a photocatalyst (eg, a photosensitive silver halide), and a silver reducing agent containing an organic binder. It is contained in a dispersed state in the matrix.
[0004]
The photothermographic material is stable at room temperature, but when heated to a high temperature (for example, 80 ° C. or higher) after exposure, a redox reaction between a reducible silver source (functioning as an oxidizing agent) and a reducing agent. To produce silver. This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, where the image is formed. A photothermographic material based on such a method has the advantage of being a monosheet and forming an image only by heat treatment, and is expected to be applied in various fields.
[0005]
However, when used for printing, photothermographic materials using the thermal development method are often thermally developed at 80 to 150 ° C., and when gelatin is used as a binder as in conventional photographic materials, the There is a problem that the dimensions change greatly due to shrinkage. Such a problem of dimensional change during thermal development can be solved by using a polymer binder that does not shrink by heating. However, it has been found that if moisture in the support disappears due to heating during thermal development and then the support is left in a room, the support absorbs moisture over time, causing another problem that the dimensions change.
[0006]
In general, when a photoengraving film is used in newspaper printing or commercial printing, a system that can always obtain a stable image has been desired. On the other hand, in the case of a photothermographic material having the above-described high-contrast photographic characteristics required for a photoengraving film, the temperature at the time of development of the highest density (Dmax) is higher than that of a conventional chemically processed film. There is a problem that the humidity dependency is large.
[0007]
As a photothermographic material having improved humidity dependency and dimensional stability, a photothermographic material having a moisture-proof layer on both sides of a support and 40 to 95% by mass of a binder constituting a dye layer being a polyester resin is used. It has been proposed (see Patent Document 1). However, there is a need for a further improved photothermographic material, that is, a photothermographic material that is less dependent on temperature and humidity during development of the maximum density (Dmax) and is most suitable for photolithography.
[0008]
[Patent Document 1]
JP-A-2002-287298
[0009]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a photothermographic material for photolithography, particularly for a scanner or an image setter, which has a small dependence on temperature and humidity at the time of development at the maximum density (Dmax).
[0010]
[Means for Solving the Problems]
The object of the present invention can be achieved by the following means.
[0011]
(1) In a photothermographic material having a photographic constituent layer including an image forming layer containing a photosensitive silver halide, a non-photosensitive organic silver salt and a reducing agent on a support, at least one of the photographic constituent layers 100 g / m2 of moisture permeability measured based on the description of JIS Z0208²-A photothermographic material containing a compound of 24 hours or less.
[0012]
(2) The moisture permeability is 100 g / m.²(1) The photothermographic material according to (1), wherein the compound of 24 hours or less is selected from ethylene / vinyl acetate copolymer, styrene / butadiene copolymer, normal paraffin chloride, and vinylidene chloride.
[0013]
(3) In a photothermographic material containing a photosensitive silver halide, a non-photosensitive organic silver salt and a reducing agent on a support, the photothermographic material is heated at 23 ° C. and a relative humidity of 10 to 20%. After exposure for 16 hours or more and image exposure, the maximum density (Dmax1) when subjected to thermal development processing at 122 ° C. for 18 seconds in an oven, and at 23 ° C. and a relative humidity of 60 to 80% for 16 hours or more and then 122 minutes in an oven A photothermographic material characterized in that the maximum density (Dmax2) after heat development at 18 ° C. for 18 seconds is Dmax2> Dmax1, and Dmax2−Dmax1 is 0.4 or less.
[0014]
(4) The method for forming an image of a photothermographic material according to any one of (1) to (3), wherein the photothermographic material according to any one of (1) to (3) is subjected to image exposure and then heat development with an automatic heat development machine. An image forming method for a photothermographic material, wherein the automatic developing machine has a preheating section before the heat developing section, and the temperature of the preheating section is set at 80 to 120C.
[0015]
Hereinafter, the present invention will be described in detail. In the present invention, the difference between the maximum densities (Dmax2-Dmax1) is determined by leaving the photothermographic material according to the present invention at 23 ° C. and a relative humidity of 10 to 20% for 16 hours or more and exposing the image to an oven. The highest density (Dmax1) when subjected to heat development at 122 ° C. for 18 seconds, and the highest density when subjected to heat development at 122 ° C. for 18 seconds in an oven after standing at 23 ° C. and a relative humidity of 60 to 80% for 16 hours or more. It means the difference when the density (Dmax2) is measured with a Macbeth TD904 densitometer (visible density).
[0016]
In order to achieve the maximum density difference of the present invention, at least one of the photographic constituent layers on the image forming layer side has a moisture permeability of 100 g / m3 as measured according to JIS Z0208.²-It can be achieved by containing a compound of 24 hrs or less. This moisture permeability is 100 g / m²Examples of the compound having a viscosity of 24 hours or less include ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, normal paraffin chloride, and vinylidene chloride. The photographic constituent layer to be contained may be an image forming layer containing a photosensitive silver halide, or a protective layer thereover, and further, the protective layer may have a moisture permeability of 100 g / m.²A mode in which a layer containing a compound of 24 hours or less is newly provided may be used.
[0017]
This moisture permeability is 100 g / m²The content of the compound of 24 hrs or less is 10 mg / m²~ 2g / m²And preferably 50 mg / m²~ 1g / m²It is.
[0018]
In the present invention, the non-photosensitive organic silver salt is a reducible silver source, and a silver salt of an organic acid and a hetero organic acid containing a reducible silver ion source, especially a long chain (10 to 30, preferably Aliphatic carboxylic acids having 15 to 25 carbon atoms) and nitrogen-containing heterocycles are preferred. Organic or inorganic silver salt complexes wherein the ligand has a total stability constant for silver ions of 4.0 to 10.0 are also useful. Examples of suitable silver salts are described in Research Disclosure (hereinafter referred to as RD) Nos. 17029 and 29996, and include the following.
[0019]
Salts of organic acids (for example, salts of gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc.); carboxyalkylthiourea salts of silver (for example, 1- (3-carboxypropyl) thio Urea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, etc.); silver complexes of polymer reaction products of aldehydes with hydroxy-substituted aromatic carboxylic acids (for example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) ), Hydroxy-substituted acids (e.g., salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid)), silver salts or complexes of thiones (e.g., 3- (2-carboxyethyl)-) 4-hydroxymethyl-4-thiazoline-2-thione, 3-carboxymethyl-4-thiazoly -2-thione), nitrogen acids and silver selected from imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole Complexes or salts with silver; silver salts such as saccharin and 5-chlorosalicylaldoxime; silver salts of mercaptides. Of these, preferred silver sources are silver behenate, arachidic acid and / or stearic acid.
[0020]
The non-photosensitive organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and is described in a forward mixing method, a reverse mixing method, a simultaneous mixing method, and JP-A No. 9-127643. A controlled double jet method or the like as described above is preferably used. For example, after adding an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.), a controlled double jet Thus, a crystal of a non-photosensitive organic silver salt is prepared by adding the soap and silver nitrate. At that time, silver halide grains may be mixed.
[0021]
In the present invention, the non-photosensitive organic silver salt preferably has an average particle size of 2 μm or less and is monodispersed. The term “monodispersion” as used herein means that the degree of dispersion determined by the following equation is 50% or less. The particle size is more preferably 40% or less, and particularly preferably 0.1% or more and 35% or less.
[0022]
Dispersity (%) = (standard deviation of particle size) / (average value of particle size) × 100
The average particle size of the non-photosensitive organic silver salt is a sphere equivalent to the volume of the non-photosensitive organic silver salt particles when the non-photosensitive organic silver salt particles are, for example, spherical, rod-shaped, or tabular particles. Means the diameter when considering. The average particle size is preferably from 0.05 to 1.5 μm, particularly preferably from 0.05 to 1.0 μm. Further, in the non-photosensitive organic silver salt of the present invention, it is preferable that 60% or more of all non-photosensitive organic silver salts are tabular grains. In the present invention, the tabular grains mean those having an aspect ratio (abbreviated as AR) of 3 or more, which is a ratio between the average grain size and the thickness, that is, the following formula.
[0023]
AR = average particle size (μm) / thickness (μm)
In order to form the non-photosensitive organic silver salt into these shapes, the non-photosensitive organic silver salt crystal can be obtained by dispersing and pulverizing the non-photosensitive organic silver salt crystal together with a binder, a surfactant and the like by a ball mill or the like. Within this range, a photosensitive material having a high density and excellent image storability can be obtained.
[0024]
As a method for producing the photosensitive silver halide grains of the present invention, a solution or dispersion of a non-photosensitive organic silver salt prepared in advance, or a sheet material containing a non-photosensitive organic silver salt, a silver halide forming component. It is preferably used to convert a part of the non-photosensitive organic silver salt into photosensitive silver halide. The silver halide thus formed is in effective contact with the non-photosensitive organic silver salt and exhibits a preferable action. Silver halide-forming components are compounds that can react with a non-photosensitive organic silver salt to form a photosensitive silver halide. To determine which compounds are applicable and effective, use the following simple test. Can be determined. That is, a non-photosensitive organic silver salt and a compound to be tested are mixed, and if necessary, after heating, it is examined whether or not there is a peak peculiar to silver halide by X-ray diffraction. Silver halide-forming components that have been confirmed to be effective by such tests include inorganic halides, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds. Are U.S. Pat. Nos. 4,009,039, 3,457,075, and 4,003,749, British Patent 1,498,956, and JP-A-53-27027. The details are described in JP-A-53-25420, and an example is shown below.
[0025]
(1) Inorganic halide: For example, MX_n(Where M is H, NH₄And n represents a metal atom, and n represents M is H and NH₄Represents 1 and M represents a valence when M is a metal atom. Examples of the metal atom include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, tin, antimony, chromium, manganese, iron, cobalt, nickel, rhodium, and cerium. Further, halogen molecules such as bromine water are also effective.
[0026]
(2) Onium halides: for example, quaternary ammonium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide, quaternary phosphonium halides such as tetraethylphosphonium bromide, and trimethyl There are tertiary sulfonium halides such as sulfonium iodides.
[0027]
(3) Halogenated hydrocarbons: for example, iodoform, bromoform, carbon tetrachloride, 2-bromo-2-methylpropane and the like.
[0028]
(4) N-halogen compounds: For example, N-chlorosuccinimide, N-bromosuccinimide, N-bromophthalimide, N-bromoacetamide, N-iodosuccinimide, N-bromophthalazone, N-bromooxazoly Non-, N-chlorophthalazone, N-bromoacetanilide, N, N-dibromobenzenesulfonamide, N-bromo-N-methylbenzenesulfonamide, 1,3-dibromo-4,4-dimethylhydantoin, N-bromourazole .
[0029]
(5) Other halogen-containing compounds: for example, triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone and the like.
[0030]
Further, in order to produce silver halide grains having a grain size of 0.01 to 0.1 μm, separately from organic silver grains, any method known in the field of photographic technology such as a single jet or double jet method is used in advance. For example, silver halide grains can be prepared by any method such as an ammonia method emulsion, a neutral method, and an acid method. Thus, it can be prepared in advance and then mixed with other components of the present invention and introduced into the composition used in the present invention. In this case, in order to sufficiently contact the photosensitive silver halide with the non-photosensitive organic silver salt, for example, U.S. Pat. Nos. 3,706,564 and 3 as protective polymers for preparing photosensitive silver halide. Polymers other than gelatin, such as polyvinyl acetals described in the specifications of U.S. Pat. No. 6,706,565, 3,713,833, and 3,748,143, and British Patent 1,362,970. Or a means for enzymatically decomposing gelatin in a light-sensitive silver halide emulsion as described in British Patent No. 1,354,186, or US Pat. No. 4,076,539. By preparing the photosensitive silver halide grains in the presence of a surfactant as described, various means such as omitting the use of the protective polymer can be applied. The silver halide grains having a grain size of 0.01 to 0.1 μm preferably have photosensitivity and function as an optical sensor. The shape of the silver halide is not particularly limited, and may be cubic, octahedral, so-called normal crystals or non-normal crystals, such as spherical, rod-shaped, and tabular grains. The silver halide composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.
[0031]
The amount of silver halide grains having a grain size of less than 0.01 μm is preferably 1% or more based on the total amount of silver halide grains, and more preferably 5% or more and 70% or less have a grain size of less than 0.01 μm. Particularly preferred are silver halide grains.
[0032]
The photosensitive silver halide used in the present invention may also be used in preparing a non-photosensitive organic silver salt, such as a halide ion, as described in GB 1,447,454. By injecting silver ions into the components coexisting with the non-photosensitive organic silver salt-forming component, the non-photosensitive organic silver salt can be formed almost simultaneously.
[0033]
These silver halide forming components are used in a small amount stoichiometrically relative to the non-photosensitive organic silver salt. Usually, the range is 0.001 to 0.7 mol, preferably 0.03 to 0.5 mol, per 1 mol of the non-photosensitive organic silver salt. Two or more silver halide forming components may be used in combination within the above range. Various conditions such as a reaction temperature, a reaction time, and a reaction pressure in the step of converting a part of the non-photosensitive organic silver salt into silver halide by using the above-mentioned silver halide forming component are appropriately set according to the purpose of production. Usually, the reaction temperature is 20 to 70 ° C., the reaction time is 0.1 second to 72 hours, and the reaction pressure is preferably set to the atmospheric pressure. This reaction is also preferably performed in the presence of a polymer used as a binder described below. The amount of the polymer used in this case is 0.01 to 100 parts by mass, preferably 0.1 to 10 parts by mass, per 1 part by mass of the non-photosensitive organic silver salt.
[0034]
The photosensitive silver halide prepared by the various methods described above can be chemically sensitized by, for example, a sulfur-containing compound, a gold compound, a platinum compound, a palladium compound, a silver compound, a tin compound, a chromium compound, or a combination thereof. . The method and procedure of this chemical sensitization are described in, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850, JP-A-51-22430, JP-A-51-78319, No. 51-81124. Further, when a part of the non-photosensitive organic silver salt is converted into a photosensitive silver halide by a silver halide forming component, as described in US Pat. No. 3,980,482, sensitization is performed. May be coexisted with a low molecular weight amide compound.
[0035]
These photosensitive silver halides include illuminance failure, and metals belonging to Groups 6 to 10 of the periodic table for the purpose of adjusting gradation, for example, ions of Rh, Ru, Re, Ir, Os, Fe, and the like. It is preferable to include the complex or complex ion. Particularly, it is preferable to add as a complex ion.₆]^2-It is preferable to add Ir complex ions such as
[0036]
The photosensitive silver halide grains in the present invention may be chemically sensitized. Preferred chemical sensitization methods include sulfur sensitization, selenium sensitization, tellurium sensitization, and noble metal sensitization such as gold compounds, platinum, palladium, and iridium compounds as well known in the art. A sensitization method can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. . Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, U.S. Pat. No. 2,448,060, British Patent 618, No. 061 can be preferably used. Specific compounds of the reduction sensitization method include, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, and the like. it can. Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Also, reduction sensitization can be achieved by introducing a single addition portion of silver ions during grain formation.
[0037]
The photothermographic material of the present invention incorporates a thermoactive reducing agent. Examples of suitable thermally active reducing agents are described in U.S. Pat. Nos. 3,770,448, 3,773,512, 3,593,863 and RD 17029 and 29963; These include:
[0038]
Aminohydroxycycloalkenonone compounds (eg, 2-hydroxypiperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents; N- Hydroxyurea derivatives (e.g., Np-methylphenyl-N-hydroxyurea); hydrazones of aldehydes or ketones (e.g., anthracenaldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (E.g., hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone and (2,5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (e.g., benzenesulfhydroxamic acid) Sulfonamidoanilines (eg, 4- (N-methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (eg, 2-methyl-5- (1-phenyl-5-tetrazolylthio) hydroquinone); tetrahydroquinoxaline (E.g., 1,2,3,4-tetrahydroquinoxaline); amide oximes; azines (e.g., a combination of an aliphatic carboxylic acid arylhydrazide and ascorbic acid); a combination of polyhydroxybenzene and hydroxylamine, reductone And / or hydrazine; hydroxanoic acids; combinations of azines and sulfonamide phenols; α-cyanophenylacetic acid derivatives; combinations of bis-β-naphthol and 1,3-dihydroxybenzene derivatives; 5-pyrazolones; Phenol reducing agents; 2-phenylindane-1,3-dione and the like; chromans; 1,4-dihydropyridines (eg, 2,6-dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine); bisphenols (Eg, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, bis (6-hydroxy-m-tri) mesitol, 2,2-bis (4-hydroxy-3-methyl) Phenyl) propane, 4,5-ethylidene-bis (2-t-butyl-6-methyl) phenol), ultraviolet-sensitive ascorbic acid derivatives, 3-pyrazolidones and the like. Among them, particularly preferred reducing agents are hindered phenols. Examples of hindered phenols include compounds represented by the following general formula (A).
[0039]
Embedded image

[0040]
In the formula, R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (for example, -C₄H₉, 2,4,4-trimethylpentyl), and R 'and R "represent an alkyl group having 1 to 5 carbon atoms (eg, methyl, ethyl, t-butyl).
[0041]
Specific examples of the compound represented by the general formula (A) are shown below. However, the present invention is not limited to the following compounds.
[0042]
Embedded image

[0043]
The amount of the reducing agent including the compound represented by the general formula (A) is preferably 1 × 10 5 per mol of silver.^-2-10 mol, especially 1 × 10^-2１．５1.5 mol.
[0044]
In the photothermographic material of the present invention, it is desirable to use an additive (hereinafter, referred to as a color tone agent) called a color tone agent, a color tone imparting agent or an activator toner together with the above-described components. The color tone agent has a function of participating in the oxidation-reduction reaction between the organic silver salt and the reducing agent to make the resulting silver image dark, particularly black. Examples of suitable toning agents are disclosed in RD 17029, and preferred toning agents include phthalazone or phthalazine.
[0045]
Examples of the photothermographic material of the present invention include those described in JP-A-63-159841, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, and JP-A-63-15245. And U.S. Pat. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, and 4,835,096. Sensitizing dyes can be used. Useful sensitizing dyes are described, for example, in the documents described or cited in RD17643 IV-A (p.23, December 1978) and Item 1831X (p.437, August 1978). In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, compounds described in JP-A-9-34078, JP-A-9-54409, and JP-A-9-80679 are preferably used.
[0046]
In the case of supersensitization, the photosensitivity becomes particularly high. Therefore, if the reducing agent is not deactivated, the printout silver after development tends to be large, which is particularly effective in the present invention. In the case of infrared sensitization, the infrared sensitizing dye further has an oxidation-reduction potential capable of reducing silver halide and organic silver salt to some extent. In the presence of a reducing agent that can reduce the organic silver salt of the above, silver clusters that become fogged silver are easily formed. The formed silver clusters also act as catalyst nuclei to induce fogging, resulting in reduced storage stability when stored in a dark place, and increased printout silver when placed in a light place after development. And other phenomena occur. Further, the sensitivity of the infrared-sensitive material extends to the heat radiation region outside the visible light range, so that it is effective in increasing the amount of printout silver due to the heat radiation even in a dark place. In particular, in the case of a photothermographic material which has been enhanced in sensitivity by a supersensitizer and has been subjected to infrared spectral sensitization, the effect is large.
[0047]
These sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is often used particularly for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are described in RD17643 (December, 1978), page 23, IV, J, or JP-B No. 9-25500, 43-4933, JP-A-59-19032, JP-A-59-192242 and JP-A-5-341432.
[0048]
As the supersensitizer, a heteroaromatic mercapto compound represented by the following general formula is preferable.
[0049]
General formula Ar-SM
In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is a heteroaromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, benzimidazole, naphthoimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotetrazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or It is quinazoline.
[0050]
In addition, a disulfide compound which substantially forms the above-mentioned mercapto compound when contained in a dispersion of an organic silver salt and / or a photosensitive silver halide grain emulsion is also included. In particular, a disulfide compound represented by the following general formula can be mentioned as a preferred example.
[0051]
General formula Ar-SS-Ar
Ar in the formula has the same meaning as in the case of Ar-SM.
[0052]
The heteroaromatic ring includes, for example, a halogen atom (eg, Cl, Br, I), a hydroxyl group, an amino group, a carboxyl group, an alkyl group (eg, one or more carbon atoms, preferably 1 to 4 carbon atoms). And a substituent selected from the group consisting of an alkoxy group (e.g., having one or more carbon atoms, preferably 1 to 4 carbon atoms).
[0053]
The supersensitizer is preferably used in the emulsion layer containing the organic silver salt and silver halide grains in the range of 0.001 to 1.0 mol per mol of silver. Particularly preferably, the amount is in the range of 0.01 to 0.5 mol per mol of silver.
[0054]
The photothermographic material of the invention may contain an antifoggant. As effective antifoggants, for example, mercury compounds known in US Pat. No. 3,589,903 and the like are environmentally undesirable. Therefore, non-mercury antifoggants have been studied for a long time. Non-mercury antifoggants include, for example, antifoggants such as those disclosed in U.S. Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-57234. preferable.
[0055]
In the present invention, in order to further improve the density fluctuation during storage with time, an oxidizing agent that reduces fog after development is used. As such an oxidizing agent, for example, JP-A-50-119624, JP-A-50-120328, JP-A-51-121332, JP-A-54-58022, JP-A-56-70543, JP-A-56-99335, and JP-A-59-59335 JP-A-90842, JP-A-61-129624, JP-A-62-129845, JP-A-6-208191, JP-A-7-5621, JP-A-7-27881, and JP-A-8-15809, U.S. Pat. , 712, 5,369,000, 5,464,737, 3,874,946, 4,756,999 and 5,340,712, European Patent Nos. 605,981A1, 622,666A1, 631,176A1, JP-B-54-165, JP-A-7-2781, and U.S. Pat. Or the like can be used compounds described in the specifications of the 665 and Nos 4,442,202, but is preferably polyhalogen compounds described in JP-A-2000-131795.
[0056]
Oxidizing agent is 10mg / m²~ 3g / m²Preferably 50 mg / m²~ 1g / m²Is more preferred. The oxidizing agent may be added by any method such as a solution, a powder and a dispersion of solid fine particles, and it is particularly preferable that the oxidizing agent is dispersed in the photosensitive layer. At the time of dispersion, a dispersion aid may be used. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent.
[0057]
In addition to the above-mentioned oxidizing agents, suitable antifoggants include compounds disclosed in U.S. Pat. Nos. 3,874,946 and 4,756,999; Compounds described in paragraphs [0030] to [0036] of JP-A-288328, compounds described in paragraphs [0062] to [0063] of JP-A-9-90550, and US Pat. No. 5,028, Compounds disclosed in JP-A No. 523 and European Patent Nos. 600,587, 631,176, and 605,981 are preferably used.
[0058]
When a polymer latex is used for the photosensitive layer, the photosensitive layer is preferably prepared by applying an aqueous coating solution and then drying. However, the term "aqueous" as used herein means that 50% by mass or more of the solvent (dispersion medium) of the coating liquid is water, and preferably 65% by mass or more of the solvent is water. As components other than water of the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80 / 15/5, water / methanol / dimethylformamide = 90/5/5 (however, the numbers represent mass%).
[0059]
To the photosensitive layer, a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added. When the photosensitive layer contains a polymer latex, the coating solution for the photosensitive layer is preferably a so-called thixotropic fluid. The thixotropic property refers to a property in which the viscosity decreases as the shear rate increases. Although any apparatus may be used for the viscosity measurement, an RFS fluid spectrometer manufactured by Rheometrics Far East Co., Ltd. is preferably used, and the viscosity is measured at 25 ° C. The viscosity of the organic silver salt-containing fluid or the thermal image forming layer coating solution in the present invention at a shear rate of 0.1 S-1 is preferably from 400 mPa · s to 100,000 mPa · s, more preferably from 500 mPa · s to 20 mPa · s. 2,000 mPa · s or less. Further, at a shear rate of 1000 S-1, it is preferably from 1 mPa · s to 200 mPa · s, more preferably from 5 mPa · s to 80 mPa · s.
[0060]
Various types of systems exhibiting thixotropic properties are known, and are described in, for example, "Lecture / Rheology" edited by Polymer Publishing Association and "Polymer Latex" (published by Polymer Publishing Association) co-authored by Muroi and Morino. In order for a fluid to exhibit thixotropic properties, it is necessary to contain a large amount of solid fine particles. In order to enhance the thixotropic property, it is effective to include a thickening linear polymer, to increase the aspect ratio of the contained solid fine particles in an anisotropic shape, to increase the alkali thickening, and to use a surfactant.
[0061]
The total amount of binder in the photosensitive layer is 0.2 to 30 g / m.², More preferably 1 to 15 g / m²Is preferable.
[0062]
In order to protect the surface of the photothermographic material and prevent abrasion, a non-photosensitive layer may be provided outside the photosensitive layer. The binder used for these non-photosensitive layers may be the same or different from the binder used for the photosensitive layers.
[0063]
In the present invention, a matting agent is preferably contained on the photosensitive layer side, and in order to prevent damage to the image after thermal development, it is preferable to provide a matting agent on the surface of the photothermographic material. Is preferably contained in a mass ratio of 0.5 to 30% with respect to all binders on the photosensitive layer side. When a non-photosensitive layer is provided on the opposite side of the photosensitive layer with the support interposed therebetween, it is preferable that at least one layer on the non-photosensitive layer side contains a matting agent, and the shape of the matting agent can be either regular or irregular. However, it is preferably a fixed shape, and a spherical shape is preferably used.
[0064]
In the photothermographic material of the invention, only a photosensitive layer may be formed on a support, but it is preferable to form at least one non-photosensitive layer on the photosensitive layer. In order to control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer may be formed on the same side as the photosensitive layer and / or an antihalation dye layer, a so-called backing layer, may be formed on the opposite side. May contain a dye or a pigment.
[0065]
These non-photosensitive layers preferably contain the binder or matting agent described above, and may further contain a slip agent such as a polysiloxane compound, wax or liquid paraffin.
[0066]
In the photothermographic material of the present invention, various surfactants can be used as a coating aid. Among them, a fluorine-based surfactant is preferably used for improving charging characteristics and preventing spot-like coating failure.
[0067]
In the invention, the antihalation layer can be provided on the side farther from the light source than the photosensitive layer. The antihalation layer preferably has a maximum absorption in a desired wavelength range of 0.1 or more and 2 or less, more preferably an absorption of an exposure wavelength of 0.2 or more and 1.5 or less, and after treatment. The absorption in the visible region is preferably 0.001 or more and less than 0.2, and more preferably a layer having an optical density of 0.001 or more and less than 0.15.
[0068]
When an antihalation dye is used in the present invention, such a dye has a desired absorption in a wavelength range, has a sufficiently low absorption in a visible region after treatment, and has a preferable absorbance spectrum shape of the antihalation layer. It may be a compound.
[0069]
For example, the following are disclosed, but the present invention is not limited thereto. Examples of the single dye include JP-A-59-56458, JP-A-2-216140, JP-A-7-13295, and JP-A-7-11432, U.S. Pat. No. 5,380,635, and JP-A-2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9, and JP-A-3-24539, page 14, lower left column, page 16, right lower column. Dyes which can be decolorized in JP-A Nos. 52-139136, 53-132334, 56-501480, 57-16060, 57-68831, 57-101835, and 59-182436. JP-A-7-36145, JP-A-7-199409, JP-B-48-33692, JP-B-50-16648, JP-B-2-41734, U.S. Pat. Nos. 4,088,497, and 4 No. 283,487, the 4,548,896 Patent, are described, for example, each specification of Nos. 5,187,049.
[0070]
The photothermographic material according to the invention is preferably a so-called one-sided photosensitive material having at least one photosensitive layer on one side of a support and a back layer on the other side.
[0071]
In the present invention, suitable binders for the backing layer are transparent or translucent, generally colorless, natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, poly (vinyl alcohol) ), Hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly ( Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) s, poly (C Tan), phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. The binder may be coated from water or an organic solvent or an emulsion.
[0072]
The back layer preferably has a maximum absorption of 0.3 or more and 2 or less in a desired wavelength range, more preferably an absorption of 0.5 or more and 2 or less, and an absorption in a visible region after the treatment. Is preferably 0.001 or more and less than 0.5, and more preferably a layer having an optical density of 0.001 or more and less than 0.3. When used for printing plate making, the absorption at 400 nm is preferably 0.001 or more and less than 0.2, and more preferably a layer having an optical density of 0.001 or more and less than 0.15. Particularly preferred. Examples of the antihalation dye used in the back layer are the same as the antihalation layer described above.
[0073]
Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other forming layers. In the photothermographic material of the present invention, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, a coating aid and the like may be used. As these additives and the other additives described above, compounds described in RD17029 (pp. 9 to 15 in June, 1978) can be preferably used.
[0074]
As the support of the present invention, a plastic film (for example, a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyamide film, a polyimide film, a cellulose triacetate film or a polycarbonate film) is preferable. An axially stretched polyethylene terephthalate film is particularly preferred. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.
[0075]
The photothermographic material of the present invention may be developed by any method, but is usually developed by elevating the temperature of the photothermographic material subjected to image exposure. The preferred development temperature is 105 to 145 ° C, more preferably 107 to 140 ° C. The development time is from 1 to 180 seconds, more preferably from 7 to 50 seconds, and particularly preferably from 8 to 25 seconds.
[0076]
The photothermographic material of the present invention is preferably heat-developed by a heat developing machine. The photothermographic material is susceptible to temperature variations in the photothermographic section, and tends to cause uneven development. Therefore, as disclosed in JP-A-9-297384, JP-A-9-297385, and JP-A-9-297386, an automatic heat developing machine of a heat drum system and a pamphlet of WO98 / 27458 are disclosed. An automatic thermal developing machine of a flat transport type is used. An automatic thermal developing machine having a preheating section before the thermal developing section and having a preheating temperature of 80 to 120 ° C. is preferably used. Preheating advances development and reduces density unevenness, which is also effective for scanning unevenness. Further, one surface of the photosensitive material is brought into contact with a fixed heating member as described in JP-A-11-133572, and the other surface of the photosensitive material is pressed against the heating member with a plurality of rollers to hold the photosensitive material. It is also preferable to carry out thermal development processing using a transporting device.
[0077]
FIG. 1 shows an example of the configuration of a heat developing machine used for the heat development of the photothermographic material of the present invention. FIG. 1 shows a side view of the heat developing machine. The heat developing machine shown in FIG. 1 heats and develops the photothermographic material 10 into a flat shape while preheating the photothermographic material 10 into a heating unit (an upper roller is a silicon rubber roller and a lower roller is an aluminum heat roller). It has a carry-out roller pair 12 that carries out the heat-developable photosensitive material 10 after development from the heating unit while correcting it into a planar shape. The photothermographic material 10 is thermally developed while being transported from the carry-in roller pair 11 to the carry-out roller pair 12. In the conveying means for conveying the photothermographic material 10 during the thermal development, a plurality of rollers 13 are provided on the side where the surface having the image forming layer contacts, and the non-woven fabric (for example, A smooth surface 14 on which an aromatic polyamide or Teflon (R) is bonded is provided. The photothermographic material 10 is conveyed while the back surface is slid over the smooth surface 14 by driving a plurality of rollers 13 that come into contact with the surface having the image forming layer. A heater 15 is provided above the roller 13 and below the smooth surface 14 so as to heat the photothermographic material 10 from both sides. As a heating means in this case, a plate heater or the like can be used. Although the clearance between the roller 13 and the smooth surface 14 varies depending on the member of the smooth surface, it is appropriately adjusted to a clearance that can transport the photothermographic material 10. Preferably it is 0 to 1 mm.
[0078]
The material of the surface of the roller 13 and the member of the smooth surface 14 are durable at high temperatures and may be anything as long as the conveyance of the photothermographic material 10 is not hindered. However, the material of the roller surface is silicon rubber, and the member of the smooth surface is aromatic. Nonwoven fabrics made of Group III polyamide or Teflon (R) (PTFE) are preferred. It is preferable to use a plurality of heaters as the heating means, and to set the heating temperature freely. The heating unit is composed of a preheating unit A having a carry-in roller pair 11 and a heat development heating unit B having a heater 15. The preheating unit A upstream of the heat development processing unit B is a heat development unit. It is desirable to set the temperature and time to be lower than the temperature (for example, about 10 to 30 ° C.) and sufficient to evaporate the amount of water in the photothermographic material 10. It is preferable that the temperature is set higher than the transition temperature (Tg) so that uneven development is not caused. The temperature distribution between the preheating section and the heat development processing section is preferably ± 1 ° C. or less, more preferably ± 0.5 ° C. or less. Further, a guide plate 16 is provided downstream of the thermal development processing unit B, and a slow cooling unit C having the carry-out roller pair 12 and the guide plate 16 is provided. The guide plate 16 is preferably made of a material having a low thermal conductivity, and is preferably cooled gradually so as not to cause deformation of the photothermographic material 10. The cooling rate is 0.5 to 10 ° C./sec. Is preferred.
[0079]
The photothermographic material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source. As the laser beam according to the present invention, a gas laser, a YAG laser, a dye laser, a semiconductor laser and the like are preferable. Among them, in order to prevent interference fringes and uneven exposure of halftone dots, it is preferable to perform vertical multiple exposure or oblique exposure.
[0080]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto.
[0081]
Example 1
<< Preparation of photothermographic material >>
(Preparation of Subbed Photographic Support)
8 W / m on both sides of a commercially available biaxially stretched heat-fixed polyethylene terephthalate film having a thickness of 125 μm.²The surface is subjected to a corona discharge treatment for one minute, and the undercoating coating solution a-1 shown below is applied to one surface so that the dry film thickness becomes 0.8 μm, and dried to form an undercoating layer A-1. The surface was coated with the following antistatic coating solution b-1 which had been subjected to the following antistatic processing so as to have a dry film thickness of 0.8 μm, and dried to obtain an antistatic processing subbing layer B-1.
[0082]
[Undercoating coating liquid a-1]
Butyl acrylate (30% by mass) / t-butyl acrylate (20% by mass)
/ Styrene (25% by mass) / 2-hydroxyethyl acrylate (25% by mass)
270 g of a copolymer latex solution (solid content: 30%)
(C-1) 0.6 g
Hexamethylene-1,6-bis (ethylene urea) 0.8 g
Polystyrene fine particles (average particle size: 3 μm) 0.05 g
0.1 g of colloidal silica (average particle size 90 μm)
Finish to 1L with water

(C-1) 0.6 g
Hexamethylene-1,6-bis (ethylene urea) 0.8 g
Finish to 1L with water.
[0083]
Subsequently, 8 W / m was formed on the surface of the undercoat layer A-1 and the undercoat layer B-1.²-Apply a corona discharge for one minute, and apply the following undercoating upper layer coating solution a-2 on the undercoating layer A-1 as the undercoating upper layer A-2 so that the dry film thickness becomes 0.1 μm. On the undercoat layer B-1, the following undercoat upper layer coating solution b-2 was applied as an undercoat upper layer B-2 having an antistatic function so that the dry film thickness was 0.8 μm.
[0084]
[Undercoat upper layer coating solution a-2]
Gelatin 0.4g / m²Mass
(C-1) 0.2 g
(C-2) 0.2 g
(C-3) 0.1 g
Silica particles (average particle size 3 μm) 0.1 g
Finish to 1L with water
[Undercoat upper layer coating solution b-2]
(C-4) 60 g
80 g of a latex liquid containing (C-5) as a component (solid content: 20%)
0.5 g of ammonium sulfate
(C-6) 12 g
6 g of polyethylene glycol (weight average molecular weight 600)
Finish to 1L with water.
[0085]
Embedded image

[0086]
Embedded image

[0087]
<Heat treatment of support>
In the undercoat drying step of the undercoated support, the support was heated at 140 ° C., and then gradually cooled. At that time, 1 × 10⁵It was transported at a tension of Pa.
[0088]
<Sample No. Preparation of 101>
(Preparation of photosensitive emulsion A)
<Preparation of silver halide emulsion A>
7.5 g of inert gelatin and 10 mg of potassium bromide are dissolved in 900 ml of water, the temperature is adjusted to 35 ° C. and the pH is adjusted to 3.0. / 2 molar ratio) with respect to silver nitrate, [Ir (NO) Cl₅1 × 10 9 salt per mole of silver^-6Moles and rhodium chloride at 1 × 10^-6370 ml of an aqueous solution containing moles was added at a constant speed over 10 minutes by the double jet method. Thereafter, 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5.0 with NaOH, and the average particle size was 0.06 μm and the degree of dispersion was 45% [100 Non-monodispersed cubic silver iodobromide grains having an area ratio of 87% were obtained.
[0089]
This emulsion was coagulated and precipitated using a gelatin coagulant, and after desalting, 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and the pAg to 7.5. Further, the resultant was chemically sensitized with chloroauric acid, inorganic sulfur, thiourea dioxide, and 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide to obtain a silver halide emulsion A.
[0090]
<Preparation of sodium behenate solution>
In 945 ml of pure water, 32.4 g of behenic acid, 9.9 g of arachidic acid and 5.6 g of stearic acid were dissolved at 90 ° C. Next, 98 ml of a 1.5 mol / L aqueous sodium hydroxide solution was added while stirring at a high speed. Next, after adding 0.93 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain a sodium behenate solution.
[0091]
<Preparation of preform emulsion A>
15.1 g of the silver halide emulsion A was added to the sodium behenate solution prepared above, the pH was adjusted to 8.1 with a sodium hydroxide solution, and 147 ml of a 1 mol / L silver nitrate solution was added over 1 minute. The mixture was further stirred for 15 minutes, and water-soluble salts were removed by ultrafiltration. The obtained silver behenate was needle-shaped particles having a long side average size of 0.8 μm. After the floc of the dispersion was formed, water was removed, and water was further washed and removed six times, followed by drying to prepare Preform Emulsion A.
[0092]
<Preparation of photosensitive emulsion A containing organic silver salt A>
To the obtained preform emulsion A, 544 g of a methyl ethyl ketone solution (17% by mass) of polyvinyl butyral (average molecular weight: 3,000) and 107 g of toluene were gradually added and mixed, and then dispersed at 4000 psi. After the dispersion, the organic silver salt particles were observed with an electron micrograph. As a result, the particles were found to be non-monodisperse organic silver salts having an average particle size of 0.7 μm and a degree of dispersion of 60%. When the organic silver salt particles were similarly observed after coating and drying, the same particles were confirmed. To 240 g of this emulsion, 4.7 ml of a 0.01% methanol solution of calcium bromide was added to obtain photosensitive emulsion A. When the silver halide grains therein were observed with an electron microscope, no silver halide grains of 0.01 μm or less were observed.
[0093]
(Coating on the back layer side)
After the back layer coating solution 1 and the back protective layer coating solution 1 having the following compositions were respectively filtered using a filter having a quasi-absolute filtration accuracy of 20 μm before coating, the support prepared above was subjected to an antistatic treatment using an extrusion coater. The film was applied on the surface of the pulling layer B-2 at a rate of 120 m / min so that the total wet film thickness became 30 μm, and dried at 60 ° C. for 4 minutes.
[0094]

[0095]
Embedded image

[0096]

(Coating on photosensitive layer side)
A photosensitive layer coating solution A having the following composition, and a surface protective layer coating solution 1 (first surface protective layer) and a surface protective layer coating solution 2 (second surface protective layer) on which a filter having a quasi-absolute filtration accuracy of 20 μm was applied. After filtration, the resultant was coated with an extrusion coater on the undercoating upper layer A-2 of the support at a rate of 100 m / min. At this time, the applied silver amount was 1.5 g / m²And applied. Thereafter, the sample was dried at 65 ° C. for 1 minute.
[0097]
The photographic constituent layer on the image forming layer side has a photosensitive layer, a first surface protective layer, and a second surface protective layer in this order on the undercoating upper layer A-2.
[0098]

[Surface protective layer coating solution 1]
Acetone 5ml / m²
Methyl ethyl ketone 21ml / m²
Cellulose acetate butyrate 2.3 g / m²
Methanol 7ml / m²
Phthalazine 250mg / m²
Vinyl sulfone compound: VS-1 35 mg / m²
Fluorinated surfactant: C₁₂F₂₅(CH₂CH₂O)₁₀C₁₂F₂₅
10mg / m²
[0099]
Embedded image

[0100]
Embedded image

[0101]

As described above, a comparative photothermographic material was prepared. This heat-developable material was used as a sample No. 101.
[0102]
<Sample No. Preparation of 102>
Sample No. In 101, the photosensitive layer coating liquid A has a moisture permeability according to the present invention of 100 g / m.²200 mg / m of normal paraffin chloride, a compound of 24 hours or less²Except for adding, sample No. 101, a photothermographic material according to the invention was prepared. This heat-developable material was used as a sample No. 102.
[0103]
<Sample No. Preparation of 103>
Sample No. In 101, the surface protective layer coating liquid 1 has a moisture permeability according to the present invention of 100 g / m.²200 mg / m of normal paraffin chloride, a compound of 24 hours or less²Except for adding, sample No. 101, a photothermographic material according to the invention was prepared. This heat-developable material was used as a sample No. 103.
[0104]
<Sample No. Production of 104>
Sample No. In 101, the photosensitive layer coating solution A and the surface protective layer coating solution 1 have the moisture permeability according to the present invention of 100 g / m2.²Normal paraffin chloride, which is a compound of 24 hours or less, is 100 mg / m2 each.²(Total 200mg / m²) Except for the sample No. 101, a photothermographic material according to the invention was prepared. This heat-developable material was used as a sample No. 104.
[0105]
<Sample No. Preparation of 105>
Sample No. 101, the surface protective layer coating solution 2 has a moisture permeability according to the present invention of 100 g / m2.²150 mg / m of normal paraffin chloride, a compound of 24 hours or less²Except for adding, sample No. 101, a photothermographic material according to the invention was prepared. This heat-developable material was used as a sample No. 105.
[0106]
《Evaluation of photographic performance》
(Exposure processing)
Each of the obtained photothermographic materials (Sample Nos. 101 to 105) was mounted with a semiconductor laser having a beam diameter (FWHM of の of the beam intensity) of 12.56 μm, a laser output of 50 mW, and an output wavelength of 783 nm. Using a single channel cylindrical inner surface type laser exposure device, the mirror rotation speed is 60,000 rpm, and the exposure time is 1.2 × 10^-8A second exposure was performed. At this time, the overlap coefficient was set to 0.449, and the laser energy density on the photothermographic material surface was 75 μJ / cm.²And
[0107]
(Heat development processing)
Each of the exposed photothermographic materials (Sample Nos. 101 to 105) was subjected to a heat development process using the heat developing machine shown in FIG. The roller surface material of the heat development processing section was made of silicone rubber, the smooth surface was made of Teflon (R) non-woven fabric, and the conveying line speed was set at 150 cm / min. Preheat section 12.2 seconds (The drive systems of the preheat section and the heat development processing section are independent, and the speed difference between the heat development processing section is set to -0.5% to -1%. The first roller temperature is 67 ° C., 2.0 seconds, the second roller temperature is 82 ° C., 2.0 seconds, the third roller temperature is 98 ° C., 2.0 seconds, the fourth roller temperature is 107 ° C. 2.0 seconds, the temperature of the fifth roller was 115 ° C., 2.0 seconds, the temperature of the sixth roller was 120 ° C., 2.0 seconds), and 17.2 in the heat development processing section at 120 ° C. (temperature of the photothermographic material surface). The heat development was performed in 13.6 seconds in the slow cooling section. The temperature accuracy in the width direction was ± 0.5 ° C. The temperature of each roller was set to be 5 cm longer on each side than the width of the photothermographic material (for example, width 61 cm), and the temperature was applied to that portion so that the temperature accuracy was improved. Since the temperature at both ends of each roller is drastically lowered, the portion 5 cm longer than the width of the photothermographic material is set so that the temperature is 1-3 ° C. higher than the center of the roller, and the photothermographic material ( Care was taken to ensure a uniform image density (eg, within 61 cm width).
[0108]
(Evaluation of photographic performance)
Regarding the development humidity dependency, the same exposure was performed when the photothermographic material left standing for 16 hours in an environment of 25 ° C. and 80% relative humidity was exposed to a 50 μm line width by the above exposure under the environment and subjected to heat development. The evaluation was made based on the difference in line width when the photothermographic material was left to stand under an environment of 20 ° C. and 10% relative humidity for 16 hours and exposed and heat-developed in that environment. Further, Dmin (fog) and Dmax (maximum density) of the image under each environment were also evaluated, and the density was measured with a Macbeth TD904 densitometer (visible density). Table 1 shows the results. In Table 1, the moisture permeability according to the present invention is 100 g / m.²-Compounds of 24 hrs or less are abbreviated as low moisture permeable compounds for convenience.
[0109]
[Table 1]

[0110]
As is clear from the results in Table 1, the photothermographic material of the present invention, Sample No. 102 to sample no. 105 indicates that the fluctuation of the maximum density (Dmax) is small even if the humidity at the time of development changes.
[0111]
Example 2
The moisture permeability according to the present invention is 100 g / m.²Sample No. in Example 1 except that the compound of 24 hours or less was changed to a styrene-butadiene copolymer. 102 to sample no. 105 in the same manner as Sample No. 105. 202 to sample no. 205 was produced. As a result of evaluating the photographic performance in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0112]
Example 3
The moisture permeability according to the present invention is 100 g / m.²Sample No. in Example 1 except that the compound of 24 hrs or less was changed to vinylidene chloride. 102 to sample no. 105 in the same manner as Sample No. 105. 302 to sample no. 305 was produced. As a result of evaluating the photographic performance in the same manner as in Example 1, the same result as in Example 1 was obtained.
[0113]
【The invention's effect】
According to the present invention, a photothermographic material for photoengraving having a small dependence on temperature and humidity during development at the maximum density (Dmax) can be provided.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of the configuration of a heat developing machine used for a heat developing process of a photothermographic material according to the present invention.
[Explanation of symbols]
10. Thermal development image forming material
11 Loading roller pair
12 Unloading roller pair
13 rollers
14 Smooth surface
15 Heater
16 Guide plate
A Preheating section
B heat development processing section
C Slow cooling section

Claims (4)

In a photothermographic material having a photographic component layer including an image-forming layer containing a photosensitive silver halide, a non-photosensitive organic silver salt and a reducing agent on a support, at least one of the photographic component layers is JIS Z0208. the photothermographic material measured moisture permeability is characterized by containing a 100g / m 2 ^· 24hrs following compounds based on the description. ^2. The heat according to claim 1, wherein the compound having a moisture permeability of 100 g / m2 · 24 hrs or less is selected from ethylene / vinyl acetate copolymer, styrene / butadiene copolymer, normal paraffin chloride and vinylidene chloride. Developed photosensitive material. In a photothermographic material containing a photosensitive silver halide, a non-photosensitive organic silver salt and a reducing agent on a support, the photothermographic material is kept at 23 ° C. and a relative humidity of 10 to 20% for 16 hours or more. After exposure and image exposure, the maximum density (Dmax1) when subjected to heat development at 122 ° C. for 18 seconds in an oven, and at 23 ° C. and a relative humidity of 60 to 80% for 16 hours or more, and then in an oven at 122 ° C., 18 A photothermographic material characterized in that the maximum density (Dmax2) after thermal development for 2 seconds is Dmax2> Dmax1, and Dmax2-Dmax1 is 0.4 or less. 4. A method for forming an image of a photothermographic material, comprising subjecting the photothermographic material according to any one of claims 1 to 3 to image exposure, and thermally developing the photothermographic material with a photothermographic automatic developing machine. An image forming method for a photothermographic material, comprising: a preheating section in front of a developing section, wherein the temperature of the preheating section is set at 80 to 120 ° C.

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