JP3997772B2 - Silver salt photothermographic dry imaging material and image forming method - Google Patents

Description

式中、Ｚ ₁ 、Ｚ ₂ 及びＺ ₃ は、各々脂肪族基、芳香族基、複素環基、−ＯＲ ₇ 、−ＮＲ ₈ （Ｒ ₉ ）、−ＳＲ ₁₀ 、−ＳｅＲ ₁₁ 、ハロゲン原子、水素原子を表す。Ｒ ₇ 、Ｒ ₁₀ 及びＲ ₁₁ は、各々脂肪族基、芳香族基、複素環基、水素原子またはカチオンを表し、Ｒ ₈ 及びＲ ₉ は、各々脂肪族基、芳香族基、複素環基または水素原子を表す。また、Ｚ ₁ とＺ ₂ 、Ｚ ₂ とＺ ₃ 、Ｚ ₃ とＺ ₁ とが、互いに環を形成してもよい。Ｃｈａｌｃｏｇｅｎは、硫黄、セレン又はテルルを表す。Ｐはリン原子を表す。
【化Ｃ】

式中、Ｚ ₄ 及びＺ ₅ は、各々アルキル基、アルケニル基、アラルキル基、アリール基、複素環基、−ＮＲ ₁ （Ｒ ₂ ）、−ＯＲ ₃ または−ＳＲ ₄ を表す。Ｒ ₁ 、Ｒ ₂ 、Ｒ ₃ およびＲ ₄ はそれぞれ同じでも異なっていてもよく、アルキル基、アラルキル基、アリール基または複素環基を表す。ただし、Ｒ ₁ 及びＲ ₂ は水素原子またはアシル基であってもよい。また、Ｚ ₄ とＺ ₅ が環を形成してもよい。Ｃｈａｌｃｏｇｅｎは、硫黄、セレン、テルルを表す。
【００４５】
Ｚ₁、Ｚ₂、Ｚ₃、Ｒ₇、Ｒ₈、Ｒ₉、Ｒ₁₀及びＲ₁₁で表される脂肪族基は、直鎖、分岐または環状のアルキル基、アルケニル基、アルキニル基、アラルキル基（例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｔ−ブチル基、ｎ−ブチル基、ｎ−オクチル基、ｎ−デシル基、ｎ−ヘキサデシル基、シクロペンチル基、シクロヘキシル基、アリル基、２−ブテニル基、３−ペンテニル基、プロパルギル基、３−ペンチニル基、ベンジル基、フェネチル基）を表す。Ｚ₁、Ｚ₂、Ｚ₃、Ｒ₇、Ｒ₈、Ｒ₉、Ｒ₁₀及びＲ₁₁で表される芳香族基は、単環または縮環のアリール基（例えば、フェニル基、ペンタフルオロフェニル基、４−クロロフェニル基、３−スルホフェニル基、α−ナフチル基、４−メチルフェニル基）を表す。Ｚ₁、Ｚ₂、Ｚ₃、Ｒ₇、Ｒ₈、Ｒ₉、Ｒ₁₀及びＲ₁₁で表される複素環基は、窒素原子、酸素原子または硫黄原子のうち少なくとも一つを含む３〜１０員環の飽和もしくは不飽和の複素環基（例えば、ピリジル基、チエニル基、フリル基、チアゾリル基、イミダゾリル基、ベンズイミダゾリル基）を表す。Ｒ₇、Ｒ₁₀及びＲ₁₁で表されるカチオンは、アルカリ金属原子またはアンモニウムを表し、Ｘで表されるハロゲン原子は、例えば、フッ素原子、塩素原子、臭素原子または沃素原子を表す。一般式（１−１）中、好ましくはＺ₁、Ｚ₂またはＺ₃が、脂肪族基、芳香族基または−ＯＲ₇であり、Ｒ₇が脂肪族基または芳香族基である。また、Ｚ₁とＺ₂、Ｚ₂とＺ₃、Ｚ₃とＺ₁とが、互いに環を形成してもよい。Ｃｈａｌｃｏｇｅｎは、硫黄原子、セレン原子又はテルル原子を表す。
【００４６】
前記一般式（１−２）において、Ｚ₄及びＺ₅は、各々アルキル基（例えば、メチル基、エチル基、ｔ−ブチル基、アダマンチル基、ｔ−オクチル基）、アルケニル基（例えば、ビニル基、プロペニル基）、アラルキル基（例えば、ベンジル基、フェネチル基）、アリール基（例えば、フェニル基、ペンタフルオロフェニル基、４−クロロフェニル基、３−ニトロフェニル基、４−オクチルスルファモイルフェニル基、α−ナフチル基）、複素環基（例えば、ピリジル基、チエニル基、フリル基、イミダゾリル基）、−ＮＲ₁（Ｒ₂）、−ＯＲ₃または−ＳＲ₄を表す。Ｒ₁、Ｒ₂、Ｒ₃及びＲ₄は、それぞれ同じでも異なっていてもよく、アルキル基、アラルキル基、アリール基または複素環基を表す。アルキル基、アラルキル基、アリール基または複素環基としては、一般式（１−１）におけるＺ₁と同様な例が挙げられる。ただし、Ｒ₁及びＲ₂は、水素原子またはアシル基（例えば、アセチル基、プロパノイル基、ベンゾイル基、ヘプタフルオロブタノイル基、ジフルオロアセチル基、４−ニトロベンゾイル基、α−ナフトイル基、４−トリフルオロメチルベンゾイル基）であってもよい。また、Ｚ₄とＺ₅が環を形成してもよい。Ｃｈａｌｃｏｇｅｎは、硫黄、セレン、テルルを表す。
【００４７】
一般式（１−１）または（１−２）で表されるカルコゲン増感剤は、酸化剤の存在に関わることなく、ハロゲン化銀粒子において、銀イオンと反応して増感核を形成し、化学増感することができる。
【００４８】
本発明において、上記一般式（１−１）及び（１−２）で表されるカルコゲン増感剤の使用量は、用いるカルコゲン増感剤の種類、ハロゲン化銀粒子、化学増感環境等により一様ではないが、概ねハロゲン化銀及び有機銀の総量１モル当たり、１０^-8〜１０^-2モルが好ましく、より好ましくは１０^-5〜１０^-3モルである。本発明における化学増感環境としては、ｐＨは６〜１０であり、より好ましくは７〜８である。温度としては、ゼラチン水溶液中の分散されたハロゲン化銀乳剤においては、３０〜６５℃が好ましく、より好ましくは４０〜５５℃である。有機溶媒中にハロゲン化銀を含むハロゲン化銀／有機銀乳剤においては、８〜３０℃が好ましく、より好ましくは１０〜２５℃である、さらに好ましくは１３〜２０℃である。また、従来技術のようにハロゲン化銀溶剤、例えば、チオシアン酸塩などを存在させると、ハロゲン化銀表面の銀イオンが増え、化学増感の速度を促進するとこができる。同様に腐食性物質、例えば、ジブロモブロメイト化合物（ＨＢｒ［Ｂｒ₂］含有の化合物、例えば、ピリジンジブロモブロメイト、ビス（ジメチルアセトアミド）ジブロモブロメイト）やハロゲン化合物（例えば、ＦｅＢｒ₃、ＦｅＣｌ₃）やハロゲン（例えば、Ｂｒ₂）や酸（例えば、塩酸、酢酸）なども使用できる。
【００４９】
本発明においては、上記一般式（１−１）及び（１−２）で表されるカルコゲン増感剤を２種以上使用しても良く、またこれらのカルコゲン増感剤に加えて、公知の化学増感剤を用いても良い。例えば、上記一般式（１−１）及び（１−２）で表されるカルコゲン増感剤におけるＣｈａｌｃｏｇｅｎが硫黄、セレン或いはテルルいずれの場合にも、公知の硫黄増感剤、セレン増感剤、テルル増感剤、還元増感剤または貴金属増感剤を組合わせて用いることが好ましい。
【００５０】
上記一般式（１−１）及び（１−２）で表されるカルコゲン増感剤は、適当な有機溶媒、例えばアルコール類（メタノール、エタノール、プロパノール、フッ素化アルコール）、ケトン類（アセトン、メチルエチルケトン）、ジメチルホルムアミド、ジメチルスルホキシド、メチルセルソルブなどに溶解して用いることができる。また、既に良く知られている乳化分散法によって、ジブチルフタレート、トリクレジルフォスフェート、グリセリルトリアセテートあるいはジエチルフタレートなどのオイル、酢酸エチルやシクロヘキサノンなどの補助溶媒を用いて溶解し、機械的に乳化分散物を作製して用いることができる。あるいは固体分散法として知られている方法によって、カルコゲン増感剤の粉末を水の中にボールミル、コロイドミル、あるいは超音波によって分散して用いることもできる。
【００５１】
一般式（１−１）及び（１−２）で表される化合物は、当業者に周知の通常の方法にて合成することができる。
【００５２】
以下に、一般式（１−１）及び（１−２）で表される化合物の具体例を示すが、本発明はこれに限定されるものではない。
【００５３】
【化４】

【００５４】
【化５】

【００５５】
【化６】

【００５６】
次に、本発明に用いられる下記一般式（Ａ）で表される化合物について説明する。
一般式（Ａ） Ｒ ¹ −Ｒ ² −Ａ−Ｍ 又は Ｒ ¹ −Ｒ ² ＝Ａ
式中、Ｒ ¹ 及びＲ ² は脂肪族基、芳香族基、ヘテロ環基又は互いに結合して環を形成することができる原子群を表す。またＲ ¹ 、Ｒ ² は同じでも異なっていてもよい。但し、Ｒ ² は２価又は３価の基を表す。Ａは硫黄原子、セレン原子又はテルル原子を表す。Ｍは水素原子、金属原子、四級アンモニウム基又はホスホニウム基を表す。
前記一般式（Ａ）において、Ｒ¹及びＲ²で表される脂肪族基としては炭素数１〜３０、好ましくは１〜２０の直鎖、又は分岐したアルキル、アルケニル、アルキニル又はシクロアルキル基が挙げられる。具体的には例えば、メチル、エチル、プロピル、ブチル、ヘキシル、デシル、ドデシル、イソプロピル、ｔ−ブチル、２−エチルヘキシル、アリル、２−ブテニル、７−オクテニル、プロパルギル、２−ブチニル、シクロプロピル、シクロペンチル、シクロヘキシル、シクロドデシル等の各基が挙げられる。Ｒ¹及びＲ²で表される芳香族基としては炭素数６〜２０のものが挙げられ、具体的には例えばフェニル、ナフチル、アントラニル等の各基が挙げられる。Ｒ¹及びＲ²で表されるヘテロ環基としては、単環でも縮合環でもよく、Ｏ、Ｓ、及びＮ原子、アミンオキシド基の少なくとも１種を環内に有する５〜６員のヘテロ環基が挙げられる。具体的には例えば、ピロリジン、ピペリジン、テトラヒドロフラン、テトラヒドロピラン、オキシラン、モルホリン、チオモルホリン、チオピラン、テトラヒドロチオフェン、ピロール、ピリジン、フラン、チオフェン、イミダゾール、ピラゾール、オキサゾール、チアゾール、イソキサゾール、イソチアゾール、トリアゾール、テトラゾール、チアジアゾール、オキサジアゾール及びこれらのベンゼローグ類から導かれる基が挙げられる。Ｒ¹及びＲ²で環を形成するものとしては員数４から７員環を挙げることができる。好ましくは５〜７員環である。Ｒ¹及びＲ²で好ましい基としてはヘテロ環基および芳香族基であり、更に好ましくはヘテロ芳香環基である。Ｒ¹及びＲ²で表される脂肪族基、芳香族基又はヘテロ環基は更に置換基により置換されていてもよく、該置換基としてはハロゲン原子（例えば塩素原子、臭素原子等）、アルキル基（例えばメチル基、エチル基、イソプロピル基、ヒドロキシエチル基、メトキシメチル基、トリフルオロメチル基、ｔ−ブチル基等）、シクロアルキル基（例えばシクロペンチル基、シクロヘキシル基等）、アラルキル基（例えばベンジル基、２−フェネチル基等）、アリール基（例えばフェニル基、ナフチル基、ｐ−トリル基、ｐ−クロロフェニル基等）、アルコキシ基（例えばメトキシ基、エトキシ基、イソプロポキシ基、ブトキシ基等）、アリールオキシ基（例えばフェノキシ基、４−メトキシフェノキシ基等）、シアノ基、アシルアミノ基（例えばアセチルアミノ基、プロピオニルアミノ基等）、アルキルチオ基（例えばメチルチオ基、エチルチオ基、ブチルチオ基等）、アリールチオ基（例えばフェニルチオ基、ｐ−メチルフェニルチオ基等）、スルホニルアミノ基（例えばメタンスルホニルアミノ基、ベンゼンスルホニルアミノ基等）、ウレイド基（例えば３−メチルウレイド基、３，３−ジメチルウレイド基、１，３−ジメチルウレイド基等）、スルファモイルアミノ基（ジメチルスルファモイルアミノ基、ジエチルスルファモイルアミノ基等）、カルバモイル基（例えばメチルカルバモイル基、エチルカルバモイル基、ジメチルカルバモイル基等）、スルファモイル基（例えばエチルスルファモイル基、ジメチルスルファモイル基等）、アルコキシカルボニル基（例えばメトキシカルボニル基、エトキシカルボニル基等）、アリールオキシカルボニル基（例えばフェノキシカルボニル基、ｐ−クロロフェノキシカルボニル基等）、スルホニル基（例えばメタンスルホニル基、ブタンスルホニル基、フェニルスルホニル基等）、アシル基（例えばアセチル基、プロパノイル基、ブチロイル基等）、アミノ基（メチルアミノ基、エチルアミノ基、ジメチルアミノ基等）、ヒドロキシ基、ニトロ基、ニトロソ基、アミンオキシド基（例えばピリジン−オキシド基等）、イミド基（例えばフタルイミド基等）、ジスルフィド基（例えばベンゼンジスルフィド基、ベンズチアゾリル−２−ジスルフィド基等）、ヘテロ環基（例えば、ピリジル基、ベンズイミダゾリル基、ベンズチアゾリル基、ベンズオキサゾリル基等）が挙げられる。Ｒ¹及びＲ²はこれらの置換基の中から単独又は複数を有することができる。またそれぞれの置換基は更に上記の置換基で置換されていてもよい。またＲ¹及びＲ²は同じでも異なっていてもよい。
【００５７】
以下に本発明で用いられる一般式（Ａ）で表される化合物の具体例を挙げるが、本発明はこれらに限定されるものではない。
【００５８】
【化７】

【００５９】
【化８】

【００６０】
【化９】

【００６１】
一般式（Ａ）で表される化合物の乳剤への添加時期は銀塩の粒子形成時、化学熟成前又は後、塗布直前のどの工程でもできる。好ましい添加時期は化学増感後から塗布直前である。好ましい添加量は１×１０^-5〜１モル／Ａｇモル、更に好ましくは１×１０^-3〜１×０．１モル／Ａｇモルである。
【００６２】
前記一般式（Ｐ１）において、Ｘ₅、Ｘ₆、Ｘ₇及びＸ₈で表されるハロゲン原子は、互いに同一でも異なっていてもよいフッ素原子、塩素原子、臭素原子、ヨウ素原子であり、好ましくは塩素原子、臭素原子、ヨウ素原子であり、より好ましくは塩素原子、臭素原子であり、特に好ましくは臭素原子である。
【００６３】
Ｂ₁及びＢ₂は各々独立に水素原子、ハロゲン原子又は置換基を表し、該置換基としては、例えば、アルキル基、アリール基、シクロアルキル基、アルケニル基、シクロアルケニル基、アルキニル基、アミノ基、アシル基、アシルオキシ基、アシルアミノ基、スルホニルアミノ基、スルファモイル基、カルバモイル基、アルキルチオ基、スルホニル基、アルキルスルホニル基、スルフィニル基、シアノ基、ヘテロ環基等が挙げられる。ｐは１以上３以下の整数を表す。
【００６４】
Ｇ₁及びＧ₂は連結基を表し、連結基としては、例えば、−ＳＯ₂−、−ＣＯ−、−ＮＨＣＯ−、−ＯＯＣ−、−Ｎ（Ｒ₈）ＳＯ₂−が挙げられ、更に、アルキル基を介して−Ｓ−、−ＮＨ−、−ＣＯ−、−Ｏ−から選ばれる基と結合して、連結基を形成してもよい。Ｒ₈は置換基を表す。Ｒ₈で表される置換基としては、前記一般式（１−１）におけるＲ₈で表される置換基と同義のものが挙げられる。Ｇ₁及びＧ₂は同じでも異なっていてもよい。但し、Ｇ₁及びＧ₂が共に−ＳＯ₂−の場合、ｐは２又は３を表す。
【００６５】
Ｊはアルキレン基、シクロアルキレン基、アルケニレン基、アルキニレン基、またはそれら各基から導かれるｐ＋１価の基を表す。好ましくは総炭素数が２〜２０のアルキレン基、シクロアルキレン基、またはそれら各基から導かれるｐ＋１価の基であり、特に好ましくは総炭素数が２〜１０のアルキレン基、シクロアルキレン基、またはそれら各基から導かれるｐ＋１価の基である。これらの基は更に置換基を有していてもよく、置換基としては、ハロゲン原子（例えば、フッ素原子、塩素原子、臭素原子等）、アルキル基（例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ｉｓｏ−ペンチル基、２−エチル−ヘキシル基、オクチル基、デシル基等）、シクロアルキル基（例えば、シクロヘキシル基、シクロヘプチル基等）、アルケニル基（例えば、エテニル−２−プロペニル基、３−ブテニル基、１−メチル−３−プロペニル基、３−ペンテニル基、１−メチル−３−ブテニル基等）、シクロアルケニル基（例えば、１−シクロアルケニル基、２−シクロアルケニル基等）、アルキニル基（例えば、エチニル基、１−プロピニル基等）、アルコキシ基（例えば、メトキシ基、エトキシ基、プロポキシ基等）、アルキルカルボニルオキシ基（例えば、アセチルオキシ基等）、アルキルチオ基（例えば、メチルチオ基、トリフルオロメチルチオ基等）、カルボキシ基、アルキルカルボニルアミノ基（例えば、アセチルアミノ基等）、ウレイド基（例えば、メチルアミノカルボニルアミノ基等）、アルキルスルホニルアミノ基（例えば、メタンスルホニルアミノ基等）、アルキルスルホニル基（例えば、メタンスルホニル基、トリフルオロメタンスルホニル基等）、カルバモイル基（例えば、カルバモイル基、Ｎ，Ｎ−ジメチルカルバモイル基、Ｎ−モルホリノカルボニル基等）、スルファモイル基（スルファモイル基、Ｎ，Ｎ−ジメチルスルファモイル基、Ｎ−モルホリノスルホニルスルファモイル基等）、トリフルオロメチル基、ヒドロキシ基、ニトロ基、シアノ基、アルキルスルホンアミド基（例えば、メタンスルホンアミド基、ブタンスルホンアミド基等）、アルキルアミノ基（例えばアミノ基、Ｎ，Ｎ−ジメチルアミノ基、Ｎ，Ｎ−ジエチルアミノ基等）、スルホ基、ホスフォノ基、サルファイト基、スルフィノ基、アルキルスルホニルアミノカルボニル基（例えば、メタンスルホニルアミノカルボニル基、エタンスルホニルアミノカルボニル基等）、アルキルカルボニルアミノスルホニル基（例えば、アセトアミドスルホニル基、メトキシアセトアミドスルホニル基等）、アルキルカルボニルアミノカルボニル基（例えば、アセトアミドカルボニル基、メトキシアセトアミドカルボニル基等）、アルキルスルフィニルアミノカルボニル基（例えば、メタンスルフィニルアミノカルボニル基、エタンスルフィニルアミノカルボニル基等）等の置換基で置換されていてもよい。また、置換基が二つ以上ある場合は、同じでも異なってもよい。但し、アリール基又はヘテロアリール基を置換基の一部として有することは無い。
【００６６】
以下に、本発明の一般式（Ｐ１）で表される化合物の具体例を挙げるが、本発明はこれらに限定されるものではない。
【００６７】
【化１０】

【００６８】
【化１１】

【００６９】
【化１２】

【００７０】
【化１３】

【００７１】
一般式（Ｐ１）で表される化合物の添加層としては、ハロゲン化銀乳剤を含む感光層でも非感光層でも添加することができるが、感光層及び／又は感光層に隣接した層であることが好ましい。また、一般式（Ｐ１）で表される化合物が銀塩光熱写真ドライイメージング材料に添加される場合、その添加量には特に制限はないが、概ねハロゲン化銀１モル当たり１０^-4モル〜１．０モル程度が好ましく、１０^-3モル〜０．３モルの範囲が特に好ましい。
【００７２】
なお、本発明においては、省銀化剤として、特願２００１−１９２６９８号明細書に記載されているような一級または二級アミノ基を２個以上有するアルコキシシラン化合物あるいはその塩を含有させることも好ましい。
【００７３】
ここで、一級または二級アミノ基を２個以上有するとは、一級アミノ基のみを２個以上、二級アミノ基のみを２個以上、さらには一級アミノ基と二級アミノ基をそれぞれ１個以上含むことを指し、アルコキシシラン化合物の塩とは、アミノ基とオニウム塩を形成しうる無機酸あるいは有機酸とアルコキシシラン化合物との付加物をさす。
【００７４】
このようなアルコキシシラン化合物あるいはその塩としては、下記に記載するようなものを挙げることができるが、本発明においては、分子内一級または二級アミノ基を２個以上有するアルコキシシラン化合物あるいはその塩で有れば、これらの化合物に限定されない。
【００７５】
【化１４】

【００７６】
【化１５】

【００７７】
【化１６】

【００７８】
これらの化合物において、アルコキシシリルを形成するアルコキシ基としては、飽和炭化水素からなるアルコキシ基が好ましく、更には、メトキシ基、エトキシ基、イソプロポキシ基がより保存安定性に優れることから好ましい。また、熱現像前の保存条件による感度変動を低減する目的においては、分子内に不飽和炭化水素基を有さない化合物がより好ましい。なお、これらのアルコキシシラン化合物あるいはその塩は１種単独でも２種以上を組み合わせて用いても良い。
【００７９】
また、画像形成層が少なくとも１個以上の一級アミノ基を有するアルコキシシラン化合物とケトン化合物との脱水縮合反応から形成されるシフ塩基を含有することが好ましい。
【００８０】
このようなシフ塩基を用いることにより、省銀化することができ、かつ熱現像前の保存時条件によらず低カブリで感度変動も少なく、ガンマも極端に立たない画像が得られる。さらに、あらかじめ一級アミン部分が封鎖されているため、後述する画像形成層形成塗工液を調製する際にケトン系溶剤を用いる場合には、塗工液調製後の時間経時による感度変動を抑制することができる。
【００８１】
上記のアルコキシシラン化合物とシフ塩基を形成する為に用いられるケトン化合物としては、特に制限なく用いることができるが、後述する画像形成方法により画像を形成した際に生じる臭気の問題から、沸点が１５０℃以下のものが好ましく、さらには１００℃以下のものがより好ましい。
【００８２】
このようなシフ塩基としては、下記に示す化合物を挙げることができるが、１個以上の一級アミノ基を有するアルコキシシラン化合物とケトン化合物との脱水縮合反応から形成されるシフ塩基で有れば、これらに限定されない。
【００８３】
【化１７】

【００８４】
【化１８】

【００８５】
なお、上述の化合物の中で、より省銀化する目的のためには、分子内に１個以上の二級アミノ基を有するシフ塩基がより好ましい。尚、これらのシフ塩基は１種単独でも２種以上を組み合わせて用いても良い。
【００８６】
省銀化剤として、アルコキシシラン化合物あるいはその塩、またはシフ塩基を画像形成層中に添加する場合は、銀１モルに対して通常０．００００１〜０．０５モルの範囲で添加するのが好ましい。また、アルコキシシラン化合物あるいはその塩と、シフ塩基の両方を画像形成層に添加する場合も同様の範疇となる。
【００８７】
しかしながら、上述のアルコキシシラン化合物またはシフ塩基の銀１モルに対する添加量が少しでも多くなると、後述する画像形成方法で形成された未露光部の画像濃度が高くなる場合がある。そこで、添加するアルコキシシラン化合物またはシフ塩基の銀１モルに対する添加量の依存性を緩和する目的で、さらに、画像形成層に分子内に２個以上のイソシアネート基を有するイソシアネート化合物を添加するのが好ましい。イソシアネート化合物としては、後述する架橋剤として使用されるイソシアネート化合物を用いることが出来る。
【００８８】
本発明において有機銀塩は還元可能な銀源であり、有機酸及びヘテロ有機酸の銀塩、特にこの中でも長鎖の（炭素数１０〜３０、好ましくは１５〜２５）脂肪族カルボン酸及び含窒素複素環化合物の銀塩が好ましい。配位子が銀イオンに対する総安定度常数として４．０〜１０．０の値をもつようなＲＤ１７０２９及び２９９６３に記載された有機又は無機の錯体も好ましい。これら好適な銀塩の例としては以下のものが挙げられる。
【００８９】
有機酸の銀塩、例えば、没食子酸、蓚酸、ベヘン酸、ステアリン酸、アラキジン酸、パルミチン酸、ラウリン酸等の銀塩。銀のカルボキシアルキルチオ尿素塩、例えば、１−（３−カルボキシプロピル）チオ尿素、１−（３−カルボキシプロピル）−３，３−ジメチルチオ尿素等の銀塩、アルデヒドとヒドロキシ置換芳香族カルボン酸とのポリマー反応生成物の銀塩乃至錯体、例えば、アルデヒド類（ホルムアルデヒド、アセトアルデヒド、ブチルアルデヒド等）とヒドロキシ置換酸類（例えば、サリチル酸、安息香酸、３，５−ジヒドロキシ安息香酸）の反応生成物の銀塩乃至錯体、チオン類の銀塩又は錯体、例えば、３−（２−カルボキシエチル）−４−ヒドロキシメチル−４−チアゾリン−２−チオン、及び３−カルボキシメチル−４−チアゾリン−２−チオン等の銀塩乃至錯体、イミダゾール、ピラゾール、ウラゾール、１，２，４−チアゾール及び１Ｈ−テトラゾール、３−アミノ−５−ベンジルチオ−１，２，４−トリアゾール及びベンズトリアゾールから選択される窒素酸と銀との錯体または塩、サッカリン、５−クロロサリチルアルドキシム等の銀塩、及びメルカプチド類の銀塩。これらの中、好ましい銀塩としてはベヘン酸銀、アラキジン酸銀及びステアリン酸銀があげられる。又、本発明においては有機銀塩が２種以上混合されていることが現像性を上げ高濃度、高コントラストの銀画像を形成する上で好ましく、例えば２種以上の有機酸混合物に銀イオン溶液を混合して調製することが好ましい。
【００９０】
有機銀塩化合物は、水溶性銀化合物と銀と錯形成する化合物を混合することにより得られるが、正混合法、逆混合法、同時混合法、特開平９−１２７６４３号に記載されている様なコントロールドダブルジェット法等が好ましく用いられる。例えば、有機酸にアルカリ金属塩（例えば、水酸化ナトリウム、水酸化カリウムなど）を加えて有機酸アルカリ金属塩ソープ（例えば、ベヘン酸ナトリウム、アラキジン酸ナトリウムなど）を作製した後に、コントロールドダブルジェット法により、前記ソープと硝酸銀などを混合して有機銀塩の結晶を作製する。その際にハロゲン化銀粒子を混在させてもよい。
【００９１】
本発明に係る有機銀塩は種々の場合において使用できるが、平板状の粒子が好ましい。特に、アスペクト比３以上の平板状有機銀塩粒子であり、且つ、最大面積を有する２枚のほぼ平行に相対する面（主平面）の形状異方性が小さくして感光層中での充填を行うため、主平面方向から計測される該平板状有機銀塩粒子の針状比率の平均値が１．１以上、１０．０未満である粒子が好ましい。なお、更に好ましい針状比率は１．１以上５．０未満である。
【００９２】
また、本発明において、アスペクト比３以上の平板状有機銀塩粒子であるとは、前記平板状有機銀塩粒子が全有機銀塩粒子の個数の５０％以上を占めることを表す。更に、本発明に係る有機銀塩は、アスペクト比３以上の平板状有機銀塩粒子が全有機銀塩粒子の個数の６０％以上を占めることが好ましく、更に好ましくは７０％以上（個数）であり、特に好ましくは８０％以上（個数）である。
【００９３】
本発明において、アスペクト比３以上の平板状粒子とは平均粒径と平均厚さの比、下記式で表されるいわゆるアスペクト比（ＡＲと略す）が３以上の粒子である。
【００９４】
ＡＲ＝平均粒径（μｍ）／平均厚さ（μｍ）
本発明に係る平板状有機銀塩粒子のアスペクト比は、好ましくは、３〜２０であり、さらに好ましくは３〜１０である。その理由としては、アスペクト比が低すぎると、有機銀塩粒子が最密されやすくなり、また、アスペクト比があまりに高い場合には、有機銀塩粒子同士が重なりやすく、また、くっついた状態で分散されやすくなるので光散乱等が起きやすくなり、その結果として銀塩光熱写真ドライイメージング材料の透明感の低下をもたらすので、上記記載の範囲が好ましい範囲と考えている。
【００９５】
上記記載の平均粒径を求めるには、分散後の有機銀塩を希釈してカーボン支持膜付きグリッド上に分散し、透過型電子顕微鏡（日本電子製、２０００ＦＸ型）、直接倍率５０００倍にて撮影を行った。スキャナにてネガをデジタル画像として取り込み、適当な画像処理ソフトを用いて粒径（円相当径）を３００個以上測定し、平均粒径を算出する。
【００９６】
上記記載の平均厚さを求めるには、下記に示すようなＴＥＭ（透過型電子顕微鏡）を用いた方法により算出する。
【００９７】
まず、支持体上に塗布された感光性層を接着剤により適当なホルダーに貼り付け、支持体面と垂直な方向にダイヤモンドナイフを用いて厚さ０．１〜０．２μｍの超薄切片を作製する。作製された超薄切片を、銅メッシュに支持させ、グロー放電により親水化されたカーボン膜上に移し液体窒素により−１３０℃以下に冷却しながら透過型電子顕微鏡（以下ＴＥＭと称す）を用いて、倍率５，０００倍乃至４０，０００倍にて明視野像を観察し、画像はフィルム、イメージングプレート、ＣＣＤカメラなどに素早く記録する。この際、観察される視野としては切片に破れや弛みがない部分を適宜選択することが好ましい。
【００９８】
カーボン膜としては極薄いコロジオン、ホルムバールなど有機膜に支持されたものを使用することが好ましく、更に好ましくは、岩塩基板上に形成し基板を溶解除去して得るか、または、上記有機膜を有機溶媒、イオンエッチングにより除去して得られたカーボン単独の膜である。ＴＥＭの加速電圧としては８０〜４００ｋＶが好ましく、特に好ましくは８０〜２００ｋＶである。
【００９９】
その他、電子顕微鏡観察技法、および試料作製技法の詳細については「日本電子顕微鏡学会関東支部編／医学・生物学電子顕微鏡観察法」（丸善）、「日本電子顕微鏡学会関東支部編／電子顕微鏡生物試料作製法」（丸善）をそれぞれ参考にすることができる。
【０１００】
適当な媒体に記録されたＴＥＭ画像は、画像１枚を少なくとも１０２４画素×１０２４画素、好ましくは２０４８画素×２０４８画素以上に分解しコンピュータによる画像処理をおこなうことが好ましい。画像処理をおこなうためには、フィルムに記録されたアナログ画像はスキャナなどでデジタル画像に変換し、シェーディング補正、コントラスト・エッジ強調などを必要に応じ施すことが好ましい。その後、ヒストグラムを作製し２値化処理によって有機銀に相当する箇所を抽出する。上記抽出した有機銀塩粒子の厚さを３００個以上適当なソフトでマニュアル測定し、平均値を求める。
【０１０１】
又、平板状有機銀塩粒子の針状比率の平均値は下記に方法により求められる。
まず、平板状有機銀塩粒子を含む感光層を光感光層バインダーを溶解可能な有機溶媒にて膨潤させて支持体上から剥離し、上記溶媒を用いた超音波洗浄、遠心分離、上澄み除去を５回繰り返す。尚、上記工程はセーフライト下に実施する。
【０１０２】
続いて、有機銀固形分濃度が０．０１％になるようにＭＥＫ（メチルエチルケトン）にて希釈し、超音波分散した後グロー放電により親水化されたポリエチレンテレフタレートフィルム上に滴下し乾燥させる。
【０１０３】
粒子が搭載されたフィルムは真空蒸着装置にてフィルム面に対して３０°の角度から厚さとして３ｎｍのＰｔ−Ｃを電子ビームにより斜め蒸着した後観察に使用することが好ましい。
【０１０４】
その他、電子顕微鏡観察技法、および試料作製技法の詳細については「日本電子顕微鏡学会関東支部編／医学・生物学電子顕微鏡観察法」（丸善）、「日本電子顕微鏡学会関東支部編／電子顕微鏡生物試料作製法」（丸善）をそれぞれ参考にすることができる。
【０１０５】
作製された試料は電界放射型走査電子顕微鏡（以下ＦＥ−ＳＥＭと称す）を用いて加速電圧２〜４ｋＶ、倍率として５０００〜２００００倍にて二次電子像を観察し、適当な記録媒体への画像保存をおこなう。
【０１０６】
上記処理のためには電子顕微鏡本体からの画像信号をＡＤ変換し直接メモリ上にデジタル情報として記録可能な装置を用いるのが便利であるが、ポラロイドフィルムなどに記録されたアナログ画像もスキャナなどでデジタル画像に変換し、シェーディング補正、コントラスト・エッジ強調などを必要に応じ施すことにより使用することができる。
【０１０７】
適当な媒体に記録された画像は、画像１枚を少なくとも１０２４画素×１０２４画素、好ましくは２０４８画素×２０４８画素以上に分解し、コンピュータによる画像処理をおこなうことが好ましい。
【０１０８】
上記記載の画像処理の手順としては、まず、ヒストグラムを作製し２値化処理によって、アスペクト比３以上の有機銀塩粒子に相当する箇所を抽出する。やむを得ず凝集した粒子は適当なアルゴリズムまたはマニュアル操作にて切断し輪郭抽出をおこなう。その後、各粒子の最大長（ＭＸ ＬＮＧ）および粒子の最小幅（ＷＩＤＴＨ）を少なくとも１０００個の粒子に関して各々測定し、各粒子ごとに下記式にて針状比率を求める。粒子の最大長とは粒子内の２点を直線で結んだ時の最大値をいう。粒子の最小幅とは粒子に外接する２本の平行線を引いた時、平行線の距離が最小値になる時の値をいう。
【０１０９】
針状比率＝（ＭＸ ＬＮＧ）÷（ＷＩＤＴＨ）
その後、計測された全粒子に関する針状比率の平均値を算出する。上記手順で計測をおこなう際にはあらかじめ、標準試料を用いて、１画素あたりの長さ補正（スケール補正）および計測系の２次元ひずみの補正を十分におこなうことが好ましい。標準試料としては米国ダウケミカル社より市販されるユニフォーム・ラテックス・パーティクルス（ＤＵＬＰ）が適当であり、０．１ないし０．３μｍの粒径に対して１０％未満の変動係数を有するポリスチレン粒子が好ましく、具体的には粒径０．２１２μｍ、標準偏差０．００２９μｍというロットが入手可能である。
【０１１０】
画像処理技術の詳細は「田中弘編 画像処理応用技術（工業調査会）」を参考にすることができ、画像処理プログラムまたは装置としては上記操作が可能なのであれば特に限定はされないが、一例としてニレコ社製Ｌｕｚｅｘ−IIIが挙げられる。
【０１１１】
前記記載の形状を有する有機銀塩粒子を得る方法としては、特に限定されないが、有機酸アルカリ金属塩ソープ形成時の混合状態および／または前記ソープに硝酸銀を添加する際の混合状態などを良好に保つ事や、ソープと反応する硝酸銀の割合を最適にすることなどが有効である。
【０１１２】
本発明に係る平板状有機銀塩粒子は必要に応じバインダーや界面活性剤などと共に予備分散した後、メディア分散機または高圧ホモジナイザなどで分散粉砕することが好ましい。上記予備分散にはアンカー型、プロペラ型等の一般的攪拌機や高速回転遠心放射型攪拌機（ディゾルバ）、高速回転剪断型撹拌機（ホモミキサ）を使用することができる。
【０１１３】
また、上記メディア分散機としては、ボールミル、遊星ボールミル、振動ボールミルなどの転動ミルや、媒体攪拌ミルであるビーズミル、アトライター、その他バスケットミルなどを用いることが可能であり、高圧ホモジナイザとしては壁、プラグなどに衝突するタイプ、液を複数に分けてから高速で液同士を衝突させるタイプ、細いオリフィスを通過させるタイプなど様々なタイプを用いることができる。
【０１１４】
メディア分散時に使用されるセラミックスビーズに用いられるセラミックスとしては、例えば、Ａｌ₂Ｏ₃、ＢａＴｉＯ₃、ＳｒＴｉＯ₃、ＭｇＯ、ＺｒＯ、ＢｅＯ、Ｃｒ₂Ｏ₃、ＳｉＯ₂、ＳｉＯ₂−Ａｌ₂Ｏ₃、Ｃｒ₂Ｏ₃−ＭｇＯ、ＭｇＯ−ＣａＯ、ＭｇＯ−Ｃ、ＭｇＯ−Ａｌ₂Ｏ₃（スピネル）、ＳｉＣ、ＴｉＯ₂、Ｋ₂Ｏ、Ｎａ₂Ｏ、ＢａＯ、ＰｂＯ、Ｂ₂Ｏ₃、ＳｒＴｉＯ₃（チタン酸ストロンチウム）、ＢｅＡｌ₂Ｏ₄、Ｙ₃Ａｌ₅Ｏ₁₂、ＺｒＯ₂−Ｙ₂Ｏ₃（立方晶ジルコニア）、３ＢｅＯ−Ａｌ₂Ｏ₃−６ＳｉＯ₂（合成エメラルド）、Ｃ（合成ダイヤモンド）、Ｓｉ₂Ｏ−ｎＨ₂Ｏ、チッカ珪素、イットリウム安定化ジルコニア、ジルコニア強化アルミナ等が好ましい。分散時におけるビーズや分散機との摩擦による不純物生成が少ない等の理由から、イットリウム安定化ジルコニア、ジルコニア強化アルミナ（これらジルコニアを含有するセラミックスを以下においてジルコニアと略す）が特に好ましく用いられる。
【０１１５】
本発明に係る平板状有機銀塩粒子を分散する際に用いられる装置類において、該有機銀塩粒子が接触する部材の材質としてジルコニア、アルミナ、窒化珪素、窒化ホウ素などのセラミックス類またはダイヤモンドを用いることが好ましく、中でも、ジルコニアを用いることが好ましい。
【０１１６】
上記分散をおこなう際、バインダー濃度は有機銀質量の０．１〜１０％添加することが好ましく、予備分散から本分散を通して液温が４５℃を上回らないことが好ましい。また、本分散の好ましい運転条件としては、例えば高圧ホモジナイザを分散手段として用いる場合には、２９．４２ＭＰａ〜９８．０６ＭＰａ、運転回数は２回以上が好ましい運転条件として挙げられる。又、メディア分散機を分散手段として用いる場合には、周速が６ｍ／秒から１３ｍ／秒が好ましい条件として挙げられる。
【０１１７】
また、ビーズや部材の一部にジルコニアを使用し、分散時に分散乳剤中に混入させることが出来る。これが写真性能上好ましく有効である。ジルコニアの破片を分散乳剤中に後添加したり、予備分散時にあらかじめ添加しておいてもよい。具体的な方法としては特に限定されないが、一例としてジルコニアビーズを充填したビーズミルにＭＥＫを循環させれば、高濃度のジルコニア溶液を得る事ができる。これを好ましい時期に好ましい濃度で添加してやればよい。
【０１１８】
感光性ハロゲン化銀と有機銀塩を含有する感光性乳剤中においては、銀１ｇあたり、０．０１ｍｇ〜０．５ｍｇのジルコニウムを含有する事が好ましく、更に好ましいジルコニウム含有量は、０．０１ｍｇ〜０．３ｍｇである。また、好ましい含有形態としては、粒径０．０２μｍ以下の微粒子である。
【０１１９】
又、本発明に係る銀塩光熱写真ドライイメージング材料においては、当該材料の支持体面と垂直な断面を電子顕微鏡観察した時、０．０２５μｍ²未満の投影面積を示す有機銀塩粒子の割合が有機銀塩粒子の全投影面積の７０％以上を示し、且つ、０．２μｍ²以上の投影面積を示す粒子の割合が有機銀塩粒子の全投影面積の１０％以下である特徴を有する有機銀塩、感光性ハロゲン化銀を含有する感光性乳剤を塗布してなるものである。このような場合、感光性乳剤中において有機銀塩粒子の凝集が少なく、且つ、均一に分布した状態を得ることが出来る。
【０１２０】
このような特徴を有する感光性乳剤を作製する条件としては、特に限定されないが、有機酸アルカリ金属塩ソープ形成時の混合状態および／または前記ソープに硝酸銀を添加する際の混合状態などを良好に保つことや、ソープと反応する硝酸銀の割合を最適にすること、分散粉砕にはメディア分散機または高圧ホモジナイザなどで分散すること、その際バインダー濃度は有機銀質量の０．１〜１０％添加すること、乾燥から本分散終了までの温度が４５℃を上回らないことなどに加えて、調液時にはディゾルバを使用し周速２．０ｍ／秒以上で攪拌することなどが好ましい条件として挙げられる。
【０１２１】
上記記載のような特定の投影面積値を有する有機銀粒子の投影面積や全投影面積にしめる割合などは、上記記載のアスペクト比３以上の平板状粒子の平均厚さを求める個所で記載したと同様に、ＴＥＭ（透過型電子顕微鏡）を用いた方法により、有機銀に相当する個所を抽出する。
【０１２２】
この際に凝集した有機銀はひとつの粒子と見なして処理し各粒子の面積（ＡＲＥＡ）を求める。同様にして少なくとも１，０００個、好ましくは２，０００個の粒子について面積を求め、それぞれについて、Ａ：０．０２５μｍ²未満、Ｂ：０．０２５μｍ²以上０．２μｍ²未満、Ｃ：０．２μｍ²以上の３つの群に分類する。本発明の銀塩光熱写真ドライイメージング材料は、Ａ群に属する粒子の面積の合計が測定された全粒子の面積の７０％以上であり、かつＣ群に属する粒子の面積の合計が測定された全粒子の面積の１０％以下を満たすものである。
【０１２３】
上記手順で計測をおこなう際にはあらかじめ、標準試料を用いて、１画素あたりの長さ補正（スケール補正）および計測系の２次元ひずみの補正を十分におこなうことが好ましい。標準試料としては米国ダウケミカル社より市販されるユニフォーム・ラテックス・パーティクルス（ＤＵＬＰ）が適当であり、０．１ないし０．３μｍの粒径に対して１０％未満の変動係数を有するポリスチレン粒子が好ましく、具体的には粒径０．２１２μｍ、標準偏差０．００２９μｍというロットが入手可能である。
【０１２４】
画像処理技術の詳細は前記と同様「田中弘編 画像処理応用技術（工業調査会）」を参考にすることができ、画像処理プログラムまたは装置としては上記操作が可能なのであれば特に限定はされないが、やはり一例として前記と同様ニレコ社製Ｌｕｚｅｘ−IIIが挙げられる。
【０１２５】
本発明に係る有機銀塩粒子は、単分散粒子であることが好ましく、好ましい単分散度としては１〜３０％であり、この範囲の単分散粒子にすることにより、濃度の高い画像が得られる。ここでいう単分散度とは、下記式で定義される。
【０１２６】
単分散度＝（粒径の標準偏差）／（粒径の平均値）×１００
上記記載の有機銀塩の平均粒径は０．０１〜０．２μｍが好ましく、更に好ましくは、０．０２〜０．１５μｍであり、平均粒径（円相当径）とは、電子顕微鏡で観察される個々の粒子像と等しい面積を有する円の直径を表す。
【０１２７】
本発明においては銀塩光熱写真ドライイメージング材料の失透を防ぐためには、ハロゲン化銀及び有機銀塩の総量は、銀量に換算して１ｍ²当たり０．５ｇ以上２．２ｇ以下であることが好ましい。この範囲にすることで硬調な画像が得られる。
【０１２８】
本発明の銀塩光熱写真ドライイメージング材料に好適なバインダーは透明又は半透明で、一般に無色であり、天然ポリマー合成樹脂やポリマー及びコポリマー、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）及びポリ（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。親水性でも非親水性でもよい。
【０１２９】
本発明に係る銀塩光熱写真ドライイメージング材料の感光層に好ましいバインダーはポリビニルアセタール類であり、特に好ましいバインダーはポリビニルブチラールである。又、上塗り層や下塗り層、特に保護層やバックコート層等の非感光層に対しては、より軟化温度の高いポリマーであるセルロースエステル類、特にトリアセチルセルロース、セルロースアセテートブチレート等のポリマーが好ましい。なお、必要に応じて、上記のバインダーは２種以上を組み合わせて用いうる。
【０１３０】
本発明に係る好ましいバインダーは下記の化合物として挙げられる。
【０１３１】
【表１】

【０１３２】
このようなバインダーは、バインダーとして機能するのに効果的な範囲で用いられる。効果的な範囲は当業者が容易に決定しうる。例えば、感光層において少なくとも有機銀塩を保持する場合の指標としては、バインダーと有機銀塩との割合は１５：１〜１：２、特に８：１〜１：１の範囲が好ましい。即ち、感光層のバインダー量が１．５〜６ｇ／ｍ²であることが好ましい。更に好ましくは１．７〜５ｇ／ｍ²である。１．５ｇ／ｍ²未満では未露光部の濃度が大幅に上昇し、使用に耐えない場合がある。
【０１３３】
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、銀塩光熱写真ドライイメージング材料の表面にマット剤を配することが好ましい。又そのマット剤は、感光層側の全バインダーに対し、質量比で０．５〜１０％含有することが好ましい。本発明において用いられるマット剤の材質は、有機物及び無機物のいずれでも良い。例えば、無機物としては、スイス特許第３３０，１５８号等に記載のシリカ、仏国特許第１，２９６，９９５号等に記載のガラス粉、英国特許第１，１７３，１８１号等に記載のアルカリ土類金属又はカドミウム、亜鉛等の炭酸塩等をマット剤として用いることができる。有機物としては、米国特許第２，３２２，０３７号等に記載の澱粉、ベルギー特許第６２５，４５１号や英国特許第９８１，１９８号等に記載された澱粉誘導体、特公昭４４−３６４３号等に記載のポリビニルアルコール、スイス特許第３３０，１５８号等に記載のポリスチレン或いはポリメタアクリレート、米国特許第３，０７９，２５７号等に記載のポリアクリロニトリル、米国特許第３，０２２，１６９号等に記載されたポリカーボネート等の有機マット剤を用いることができる。マット剤の形状は、定形、不定形いずれでも良いが、好ましくは定形で、特に球形が好ましく用いられる。マット剤の大きさは、マット剤の体積を球形に換算したときの直径で表され、本発明におけるマット剤の粒径とは、この球形換算した直径のことを示すものとする。本発明に用いられるマット剤は、平均粒径が０．５〜１０μｍであることが好ましく、更に好ましくは１．０〜８．０μｍである。又、粒子サイズ分布の変動係数としては、５０％以下であることが好ましく、更に好ましくは４０％以下であり、特に好ましくは３０％以下となるマット剤である。ここでいう粒子サイズ分布の変動係数とは、
変動係数＝（粒径の標準偏差）／（粒径の平均値）×１００（％）
で表される。本発明において、マット剤は任意の構成層中に含むことができるが、好ましくは感光層以外の構成層に添加することであり、更に好ましくは支持体から見て最も外側の層への添加である。マット剤の添加方法は、予め塗布液中に分散させて塗布する方法であっても良いし、或いは塗布液を塗布し乾燥が終了する迄の間にマット剤を噴霧する方法を用いても良い。また、複数の種類のマット剤を添加する場合には、上記両者の方法を併用しても良い。
【０１３４】
本発明の銀塩光熱写真ドライイメージング材料は、支持体上に少なくとも一層の感光層を有している。支持体の上に感光層のみを形成しても良いが、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。感光層を通過する光の量又は波長分布を制御するため、感光層と同じ側又は反対側にフィルター層を形成しても良いし、感光層に直接、本発明に係る染料や公知の顔料等を含ませても良い。感光層は、複数層にしても良く、階調の調節のため感度の異なる構成、例えば高感層／低感層又は低感層／高感層にしても良い。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良い。本発明の銀塩光熱写真ドライイメージング材料には、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良い。
【０１３５】
本発明の銀塩光熱写真ドライイメージング材料には、色調剤を添加することが好ましい。好適な色調剤の例は、ＲＤ第１７０２９号に開示されており、具体的には以下のものを挙げることができる。すなわち、イミド類（例えば、フタルイミド）；環状イミド類、ピラゾリン−５−オン類、及びキナゾリノン（例えば、スクシンイミド、３−フェニル−２−ピラゾリン−５−オン、１−フェニルウラゾール、キナゾリン及び２，４−チアゾリジンジオン）；ナフタールイミド類（例えば、Ｎ−ヒドロキシ−１，８−ナフタールイミド）；コバルト錯体（例えば、コバルトのヘキサミントリフルオロアセテート）、メルカプタン類（例えば、３−メルカプト−１，２，４−トリアゾール）；Ｎ−（アミノメチル）アリールジカルボキシイミド類（例えば、Ｎ−（ジメチルアミノメチル）フタルイミド）；ブロックされたピラゾール類、イソチウロニウム（ｉｓｏｔｈｉｕｒｏｎｉｕｍ）誘導体及びある種の光漂白剤の組み合わせ（例えば、Ｎ，Ｎ′−ヘキサメチレン（１−カルバモイル−３，５−ジメチルピラゾール）、１，８−（３，６−ジオキサオクタン）ビス（イソチウロニウムトリフルオロアセテート）、及び２−（トリブロモメチルスルホニル）ベンゾチアゾールの組み合わせ）；メロシアニン染料（例えば、３−エチル−５−（（３−エチル−２−ベンゾチアゾリニリデン（ベンゾチアゾリニリデン））−１−メチルエチリデン）−２−チオ−２，４−オキサゾリジンジオン）；フタラジノン、フタラジノン誘導体又はこれらの誘導体の金属塩（例えば、４−（１−ナフチル）フタラジノン、６−クロロフタラジノン、５，７−ジメチルオキシフタラジノン、及び２，３−ジヒドロ−１，４−フタラジンジオン）；フタラジノンとスルフィン酸誘導体の組み合わせ（例えば、６−クロロフタラジノン＋ベンゼンスルフィン酸ナトリウム又は８−メチルフタラジノン＋ｐ−トリスルホン酸ナトリウム）；フタラジン＋フタル酸の組み合わせ；フタラジン（フタラジンの付加物を含む）とマレイン酸無水物、及びフタル酸、２，３−ナフタレンジカルボン酸又はｏ−フェニレン酸誘導体及びその無水物（例えば、フタル酸、４−メチルフタル酸、４−ニトロフタル酸及びテトラクロロフタル酸無水物）から選択される少なくとも１つの化合物との組み合わせ；キナゾリンジオン類、ベンズオキサジン、ナルトキサジン誘導体；ベンズオキサジン−２，４−ジオン類（例えば、１，３−ベンズオキサジン−２，４−ジオン）；ピリミジン類及び不斉−トリアジン類（例えば、２，４−ジヒドロキシピリミジン）、及びテトラアザペンタレン誘導体（例えば、３，６−ジメルカプト−１，４−ジフェニル−１Ｈ，４Ｈ−２，３ａ，５，６ａ−テトラアザペンタレン）等を挙げることができ、特に好ましい色調剤は、フタラゾン又はフタラジンである。
【０１３６】
本発明の銀塩光熱写真ドライイメージング材料には、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、米国特許第４，６３９，４１４号、同第４，７４０，４５５号、同第４，７４１，９６６号、同第４，７５１，１７５号及び同第４，８３５，０９６号に記載された増感色素が使用できる。
【０１３７】
本発明に使用される有用な増感色素は、例えばＲＤ Ｉｔｅｍ ７６４３IV−Ａ項（１９７８年１２月ｐ．２３）、同Ｉｔｅｍ １８３１Ｘ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好ましい。
【０１３８】
例えばＡ）アルゴンレーザ光源に対しては、特開昭６０−１６２２４７号、特開平２−４８６５３号、米国特許第２，１６１，３３１号、西独特許第９３６，０７１号記載のシンプルメロシアニン類、Ｂ）ヘリウム−ネオンレーザ光源に対しては、特開昭５０−６２４２５号、同５４−１８７２６号、同５９−１０２２２９号に示された三核シアニン色素類に示されたメロシアニン類、Ｃ）ＬＥＤ光源及び赤色半導体レーザに対しては特公昭４８−４２１７２号、同５１−９６０９号、同５５−３９８１８号、特開昭６２−２８４３４３号、特開平２−１０５１３５号に記載されたチアカルボシアニン類、Ｄ）赤外半導体レーザ光源に対しては特開昭５９−１９１０３２号、特開昭６０−８０８４１号に記載されたトリカルボシアニン類、特開昭５９−１９２２４２号、特開平３−６７２４２号の一般式（IIIａ）、一般式（IIIｂ）で表される４−キノリン核を含有するジカルボシアニン類などが有利に選択される。赤外レーザ光源の波長は、７５０ｎｍ以上、さらには８００ｎｍ以上であることが好ましく、このような波長域のレーザに対応させるためには、特開平４−１８２６３９号、同５−３４１４３２号、特公平６−５２３８７号、同３−１０９３１号、米国特許第５，４４１，８６６号、特開平７−１３２９５号等に記載されている増感色素が好ましく用いられる。これらの増感色素は、単独に用いてもよいが、それらを組合せて用いてもよく、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。これは、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、強色増感作用を示す物質をハロゲン化銀乳剤中に含むことである。
【０１３９】
本発明の銀塩光熱写真ドライイメージング材料は、上述した各構成層の素材を溶媒に溶解又は分散させた塗布液を作り、それら塗布液を複数同時に重層塗布した後、加熱処理を行って形成されることが好ましい。ここで「複数同時に重層塗布」とは、各構成層（例えば感光層、保護層）の塗布液を作製し、これを支持体へ塗布する際に各層個別に塗布、乾燥の繰り返しをするのではなく、同時に重層塗布を行い乾燥する工程も同時に行える状態で各構成層を形成しうることを意味する。即ち、下層中の全溶剤の残存量が７０質量％以下となる前に、上層を設けることである。
【０１４０】
各構成層を複数同時に重層塗布する方法には特に制限はなく、例えばバーコーター法、カーテンコート法、浸漬法、エアーナイフ法、ホッパー塗布法、エクストリュージョン塗布法などの公知の方法を用いることができる。これらのうちより好ましくはエクストリュージョン塗布法と呼ばれる前計量タイプの塗布方式である。該エクストリュージョン塗布法はスライド塗布方式のようにスライド面での揮発がないため、精密塗布、有機溶剤塗布に適している。この塗布方法は感光層を有する側について述べたが、バックコート層を設ける際、下引きとともに塗布する場合についても同様である。
【０１４１】
本発明の光熱写真ドライイメージング材料の露光は、当該感材に付与した感色性に対し適切な光源を用いることが望ましい。例えば、当該感材を赤外光に感じ得るものとした場合は、赤外光域ならば如何なる光源にも適用可能であるが、レーザパワーがハイパワーである事や、銀塩光熱写真ドライイメージング材料を透明にできる等の点から、赤外半導体レーザ（７８０ｎｍ〜８２０ｎｍ）がより好ましく用いられる。
【０１４２】
本発明において、露光はレーザ走査露光により行うことが好ましいが、その露光方法には種々の方法が採用できる。例えば、第１の好ましい方法として、銀塩光熱写真ドライイメージング材料の露光面と走査レーザ光のなす角が実質的に垂直になることがないレーザ走査露光機を用いる方法が挙げられる。
【０１４３】
ここで、「実質的に垂直になることがない」とはレーザ走査中に最も垂直に近い角度として好ましくは５５度以上８８度以下、より好ましくは６０度以上８６度以下、更に好ましくは６５度以上８４度以下、最も好ましくは７０度以上８２度以下であることをいう。
【０１４４】
レーザ光が、銀塩光熱写真ドライイメージング材料に走査されるときの銀塩光熱写真ドライイメージング材料露光面でのビームスポット直径は、好ましくは２００μｍ以下、より好ましくは１００μｍ以下である。これは、スポット径が小さい方がレーザ入射角度の垂直からのずらし角度を減らせる点で好ましい。なお、ビームスポット直径の下限は１０μｍである。このようなレーザ走査露光を行うことにより干渉縞様のムラの発生等のような反射光に係る画質劣化を減じることが出来る。
【０１４５】
また、第２の方法として、本発明における露光は縦マルチである走査レーザ光を発するレーザ走査露光機を用いて行うことも好ましい。縦単一モードの走査レーザ光に比べて干渉縞様のムラの発生等の画質劣化が減少する。
【０１４６】
縦マルチ化するには、合波による、戻り光を利用する、高周波重畳をかける、などの方法がよい。なお、縦マルチとは、露光波長が単一でないことを意味し、通常露光波長の分布が５ｎｍ以上、好ましくは１０ｎｍ以上になるとよい。露光波長の分布の上限には特に制限はないが、通常６０ｎｍ程度である。
【０１４７】
更に、第３の態様としては、２本以上のレーザを用いて、走査露光により画像を形成することも好ましい。
【０１４８】
このような複数本のレーザを利用した画像記録方法としては、高解像度化、高速化の要求から１回の走査で複数ラインずつ画像を書き込むレーザプリンタやデジタル複写機の画像書込み手段で使用されている技術であり、例えば特開昭６０−１６６９１６号公報等により知られている。これは、光源ユニットから放射されたレーザ光をポリゴンミラーで偏向走査し、ｆθレンズ等を介して感光体上に結像する方法であり、これはレーザイメージャなどと原理的に同じレーザ走査光学装置である。
【０１４９】
レーザプリンタやデジタル複写機の画像書込み手段における感光体上へのレーザ光の結像は、１回の走査で複数ラインずつ画像を書き込むという用途から、一つのレーザ光の結像位置から１ライン分ずらして次のレーザ光が結像されている。具体的には、二つの光ビームは互いに副走査方向に像面上で数１０μｍオーダーの間隔で近接しており、印字密度が４００ｄｐｉ（本発明においては、１インチ即ち、２．５４ｃｍ当たりに１ドットの印字密度のことをｄｐｉ（ドットパーインチ）と定義する）で２ビームの副走査方向ピッチは６３．５μｍ、６００ｄｐｉで４２．３μｍである。従来の副走査方向に解像度分ずらした方法とは異なり、本発明では同一の場所に２本以上のレーザを入射角を変え露光面に集光させ画像形成することが好ましい。この際の、通常の１本のレーザ（波長λ［ｎｍ］）で書き込む場合の露光面での露光エネルギーがＥである場合に、露光に使用するＮ本のレーザが同一波長（波長λ［ｎｍ］）、同一露光エネルギー（Ｅｎ）とした場合、０．９×Ｅ≦Ｅｎ×Ｎ≦１．１×Ｅの範囲にするのが好ましい。このようにすることにより、露光面ではエネルギーは確保されるが、それぞれのレーザ光の画像形成層への反射は、レーザの露光エネルギーが低いため低減され、ひいては干渉縞の発生が抑えられる。
【０１５０】
なお、上述では複数本のレーザの波長をλと同一のものを使用したが、波長の異なるものを用いても良い。この場合、λ［ｎｍ］に対して（λ−３０）＜λ１、λ２、・・・・・λｎ≦（λ＋３０）の範囲にするのが好ましい。
【０１５１】
なお、上述した第１、第２、第３の態様の画像記録方法において、走査露光に用いるレーザとしては、一般によく知られている、ルビーレーザ、ＹＡＧレーザ、ガラスレーザ等の固体レーザ；Ｈｅ−Ｎｅレーザ、Ａｒイオンレーザ、Ｋｒイオンレーザ、ＣＯ₂レーザ、ＣＯレーザ、Ｈｅ−Ｃｄレーザ、Ｎ₂レーザ、エキシマーレーザ等の気体レーザ；ＩｎＧａＰレーザ、ＡｌＧａＡｓレーザ、ＧａＡｓＰレーザ、ＩｎＧａＡｓレーザ、ＩｎＡｓＰレーザ、ＣｄＳｎＰ₂レーザ、ＧａＳｂレーザ等の半導体レーザ；化学レーザ、色素レーザ等を用途に併せて適時選択して使用できるが、これらの中でもメンテナンスや光源の大きさの問題から、波長が６００〜１２００ｎｍの半導体レーザを用いるのが好ましい。なお、レーザ・イメージャやレーザ・イメージセッタで使用されるレーザにおいて、銀塩光熱写真ドライイメージング材料に走査されるときの該材料露光面でのビームスポット径は、一般に短軸径として５〜７５μｍ、長軸径として５〜１００μｍの範囲であり、レーザ光走査速度は銀塩光熱写真ドライイメージング材料固有のレーザ発振波長における感度とレーザパワーによって、銀塩光熱写真ドライイメージング材料毎に最適な値に設定することができる。
【０１５２】
本発明に於いて、現像条件は使用する機器、装置、或いは手段に依存して変化するが、典型的には適した高温に於いて像様に露光した光熱写真ドライイメージング材料を加熱することを伴う。露光後に得られた潜像は、中程度の高温（例えば、約８０〜２００℃、好ましくは約１００〜２００℃）で十分な時間（一般には約１秒〜約２分間）、銀塩光熱写真ドライイメージング材料を加熱することにより現像することができる。
【０１５３】
加熱温度が８０℃以下では短時間に十分な画像濃度が得られず、又２００℃以上ではバインダーが溶融し、ローラーへの転写など、画像そのものだけでなく搬送性や、現像機等へも悪影響を及ぼす。加熱することで有機銀塩（酸化剤として機能する）と還元剤との間の酸化還元反応により銀画像を生成する。この反応過程は、外部からの水等の処理液の一切の供給なしに進行する。
【０１５４】
加熱する機器、装置、或いは手段はホットプレート、アイロン、ホットローラー、炭素又は白色チタン等を用いた熱発生器として典型的な加熱手段で行ってよい。より好ましくは本発明に係わる保護層の設けられた銀塩光熱写真ドライイメージング材料は、保護層を有する側の面を加熱手段と接触させ加熱処理するのが、均一な加熱を行う上で、又熱効率、作業性の点などから好ましく、該面をヒートローラに接触させながら搬送し加熱処理して現像することが好ましい。
【０１５５】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明はこれらに限定されない。
【０１５６】
参考例１
《銀塩光熱写真ドライイメージング材料試料の作製》
以下に示す方法に従い、銀塩光熱写真ドライイメージング材料を作製した。
【０１５７】
（支持体の作製）
濃度０．１６０（コニカ社製デンシトメーターＰＤＡ−６５での測定値）に青色着色した、厚み１７５μｍのポリエチレンテレフタレートフィルムの両面に８Ｗ／ｍ²・分のコロナ放電処理を施した。
【０１５８】
（感光性乳剤の調製）
〔感光性ハロゲン化銀乳剤１の調製〕
Ａ１
フェニルカルバモイルゼラチン ８８．３ｇ
化合物（Ａ）（１０％メタノール溶液） １０ｍｌ
臭化カリウム ０．３２ｇ
水で５４２９ｍｌに仕上げる
Ｂ１
０．６７Ｍ／Ｌ硝酸銀水溶液 ２６３５ｍｌ
Ｃ１
臭化カリウム ５１．５５ｇ
沃化カリウム １．４７ｇ
水で６６０ｍｌに仕上げる
Ｄ１
臭化カリウム １５４．９ｇ
沃化カリウム ４．４１ｇ
Ｅ１
０．４Ｍ／Ｌ臭化カリウム水溶液 下記銀電位制御量
Ｆ１
５６％酢酸水溶液 １６．０ｍｌ
Ｇ１
無水炭酸ナトリウム １．７２ｇ
水で１５１ｍｌに仕上げる
化合物（Ａ）：
ＨＯ（ＣＨ₂ＣＨ₂Ｏ）_n−［ＣＨ（ＣＨ₃）ＣＨ₂Ｏ］₁₇−（ＣＨ₂ＣＨ₂Ｏ）_mＨ
ｍ＋ｎ＝５〜７
特公昭５８−５８２８８号、同５８−５８２８９号に示される混合撹拌機を用いて溶液（Ａ１）に溶液（Ｂ１）の１／４量及び溶液（Ｃ１）全量を４５℃、ｐＡｇ８．０９に制御しながら、同時混合法により４分４５秒を要して添加し、核形成を行った。
【０１５９】
７分間経過後、溶液（Ｂ１）の残り及び溶液（Ｄ１）の全量を、温度４５℃、ｐＡｇ８．０９に制御しながら、同時混合法により１４分１５秒かけて添加した。混合中、反応溶液のｐＨは５．６であった。
【０１６０】
５分間撹拌した後、４０℃に降温し、溶液（Ｆ１）を全量添加し、ハロゲン化銀乳剤を沈降させた。沈降部分２０００ｍｌを残し上澄み液を取り除き、水を１０Ｌ加え、撹拌後、再度ハロゲン化銀を沈降させた。沈降部分１５００ｍｌを残し、上澄み液を取り除き、更に水を１０Ｌ加え、撹拌後、ハロゲン化銀を沈降させた。沈降部分１５００ｍｌを残し、上澄み液を取り除いた後、溶液（Ｇ１）を加え、６０℃に昇温し、更に１２０分撹拌した。最後にｐＨが５．８になるように調整し、銀量１モル当たり１１６１ｇになるように水を添加した。
【０１６１】
得られた感光性ハロゲン化銀乳剤１は平均粒子サイズ０．０６１μｍ、粒子サイズの変動係数１２％、［１００］面比率９２％の立方体沃臭化銀粒子であった。
【０１６２】
次に上記感光性ハロゲン化銀乳剤１を６０℃にて、ｐＨを７に調整した。チオ硫酸ナトリウム１×１０^-4モル／Ａｇモル及びトリフェニルホスフィンセレナイド０．２×１０^-4モル／Ａｇモル固体微粒子状分散物を加え、チオシアン酸アンモニウム５．８×１０^-3モル／Ａｇモル、塩化金酸０．４×１０^-4モル／Ａｇモルを加えた。１２０分間攪拌した。一般式（Ａ）のかぶり抑制剤を表２記載のように加えた。熟成した後に３８℃に冷却して化学増感を終了し、これを感光性ハロゲン化銀乳剤Ｅｍ−１ａ〜Ｅｍ−１ｇとする。
【０１６３】
〔感光性ハロゲン化銀乳剤Ｅｍ−２ａ、２ｂの調製〕
上記感光性ハロゲン化銀乳剤１をｐＨ５．８のままで化学増感を行い、感光性ハロゲン化銀乳剤Ｅｍ−２ａとする。また、一般式（Ａ）のかぶり抑制剤を表２記載のように加えＥｍ−２ｂとする。
【０１６４】
〔粉末有機銀塩−１ａ〜１ｇの調製〕
４７２０ｍｌの純水にベヘン酸１０４．６ｇ、アラキジン酸５４．２ｇ、ステアリン酸３４．９ｇ、パルミチン酸１．８ｇを８０℃で溶解した。次いで、高速で攪拌しながら１．５Ｍ／Ｌの水酸化ナトリウム水溶液５４０．２ｍｌを添加し、濃硝酸６．９ｍｌを加えた後、５５℃に冷却して有機酸ナトリウム溶液を得た。該有機酸ナトリウム溶液の温度を５５℃に保ったまま、銀として０．０３８モル相当の上記感光性ハロゲン化銀乳剤Ｅｍ−１ａと純水４５０ｍｌを添加し、５分間高速で攪拌した。次に１Ｍ／Ｌの硝酸銀溶液７６０．６ｍｌを２分間かけて添加し、さらに１０分間高速で攪拌した後、濾過により水溶性塩類を除去した。その後、濾液の電導度が２μＳ／ｃｍになるまで脱イオン水による水洗、濾過を繰り返し、遠心脱水を行った後、質量の減少がなくなるまで加熱した窒素気流下で乾燥を行った。粉末有機銀塩−１ａを得た。また、感光性ハロゲン化銀乳剤Ｅｍ−１ｂ〜Ｅｍ−１ｇからも同様な方法で粉末有機銀塩−１ｂ〜１ｇを得た。
【０１６５】
〔粉末有機銀塩−２ａ、２ｂの調製〕
感光性ハロゲン化銀乳剤Ｅｍ−２ａ、２ｂを用いて、上記と同じように粉末有機銀塩−２ａ、２ｂを得た。
【０１６６】
〔感光性乳剤分散液−１ａ〜１ｇの調製〕
ポリビニルブチラール粉末（Ｍｏｎｓａｎｔｏ社 Ｂｕｔｖａｒ Ｂ−７９）１４．５７ｇをメチルエチルケトン（以降、ＭＥＫと略す）１４５７ｇに溶解し、ディゾルバー型ホモジナイザーにて攪拌しながら、５００ｇの粉末有機銀塩−１ａを徐々に添加して十分に混合した。その後１ｍｍ径のＺｒビーズ（東レ製）を８０％充填したメディア型分散機（ｇｅｔｔｚｍａｎｎ社製）にて周速１３ｍ、ミル内滞留時間０．５分間にて分散を行った。このように感光性乳剤分散液−１ａを調製した。また、粉末有機銀塩１ｂ〜１ｇからも同様な方法で感光性乳剤分散液−１ｂ〜１ｇを得た。
【０１６７】
〔感光性乳剤分散液−２ａ、２ｂの調製〕
ポリビニルブチラール粉末（Ｍｏｎｓａｎｔｏ社 Ｂｕｔｖａｒ Ｂ−７９）１４．５７ｇをメチルエチルケトン（以降、ＭＥＫと略す）１４５７ｇに溶解し、ディゾルバー型ホモジナイザーにて攪拌しながら、５００ｇの粉末有機銀塩−２ａ又は２ｂをそれぞれ徐々に添加して十分に混合した。その後１ｍｍ径のＺｒビーズ（東レ製）を８０％充填したメディア型分散機（ｇｅｔｔｚｍａｎｎ社製）にて周速１３ｍ、ミル内滞留時間０．５分間にて分散を行い、感光性乳剤分散液−２ａ及び２ｂを調製した。
【０１６８】
（塗布液の調製）
安定剤液の調製
１．０ｇの安定剤−１、０．３１ｇの酢酸カリウムをメタノール４．９７ｇに溶解し安定剤液を調製した。
【０１６９】
赤外増感色素液の調製
１９．２ｍｇの赤外増感色素Ｄｙｅ−１、１．４８８ｇの２−クロロ−安息香酸、２．７７９ｇの安定剤−２を３１．３ｍｌのＭＥＫに溶解し赤外増感色素液を調製した。
【０１７０】
添加液ａの調製
０．２５モル／Ａｇモルの還元剤、１．５４ｇの４−メチルフタル酸、０．４８ｇの赤外染料をＭＥＫ１１０ｇに溶解し添加液ａとした。
【０１７１】
添加液ｂの調製
３．５６ｇのかぶり防止剤、３．４３ｇのフタラジンをＭＥＫ４０．９ｇに溶解し添加液ｂとした。
【０１７２】
〔感光層塗布液１ａ〜１ｇ、２ａ、２ｂの調製〕
前記感光性乳剤分散液１ａ〜１ｇ、２ａ、２ｂをそれぞれ（５０ｇ）およびＭＥＫ１５．１１ｇを攪拌しながら１７℃に保温し、かぶり抑制剤ビス（ジメチルアセトアミド）ジブロモブロメイト（１０％メタノール溶液）０．３２ｇを加え、１時間攪拌した。続いて、安定剤液０．３４ｇを添加して１０分間攪拌した後、２．０ｇの赤外増感色素液を添加して１時間攪拌した。その後、温度を１３℃まで降温してさらに２５分攪拌した。安定剤−３の０．２％メタノール溶液を２ｇ添加した。５分後、バインダー樹脂としてポリビニルアセタール樹脂Ｐ−１を１３．３１ｇ添加して３０分攪拌した後、テトラクロロフタル酸（９．４質量％ＭＥＫ溶液）１．０８４ｇを添加して１５分間攪拌した。さらに攪拌を続けながら、１．６ｍｌのＤｅｓｍｏｄｕｒＮ３３００／モーベイ社製の脂肪族イソシアネート（１０％ＭＥＫ溶液）、１２．４３ｇの添加液ａ、４．２７ｇの添加液ｂを順次添加し攪拌することにより感光層塗布液１ａ〜１ｇ、２ａ、２ｂを得た。
【０１７３】
【化１９】

【０１７４】
【化２０】

【０１７５】
ＭＥＫを８６５ｇ攪拌しながら、セルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社製、ＣＡＢ１７１−１５）を９６ｇ、ポリメチルメタクリル酸（ローム＆ハース社製、パラロイドＡ−２１）を４．５ｇ、ビニルスルホン化合物ＨＤ−１（＊１）を１．５ｇ、ベンゾトリアゾールを１．０ｇ、Ｆ系活性剤（旭硝子社製、サーフロンＫＨ４０）を１．０ｇ添加し溶解した。次に下記マット剤分散液３０ｇを添加して攪拌しながら、フタラジン１５ｇを添加して、表面保護層塗布液を調製した。
【０１７６】
（＊１）ＨＤ−１：１，３−｛ビス（ビニルスルホニル）｝−２−ヒドロキシプロパン
〈マット剤分散液の調製〉
セルロースアセテートブチレート（Ｅａｓｔｍａｎ Ｃｈｅｍｉｃａｌ社製、ＣＡＢ１７１−１５）７．５ｇをＭＥＫ４２．５ｇに溶解し、その中に、炭酸カルシウム（Ｓｐｅｃｉａｌｉｔｙ Ｍｉｎｅｒａｌｓ社製、Ｓｕｐｅｒ−Ｐｆｌｅｘ２００）５ｇを添加し、ディゾルバー型ホモジナイザーにて８０００ｒｐｍで３０ｍｉｎ分散しマット剤分散液を調製した。
【０１７７】
〔バック面塗布液の調製〕
ＭＥＫ８３０ｇを攪拌しながら、セルロースアセテートブチレート（ＥａｓｔｍａｎＣｈｅｍｉｃａｌ社製、ＣＡＢ３８１−２０）８４．２ｇ、ポリエステル樹脂（Ｂｏｓｔｉｃ社製、ＶｉｔｅｌＰＥ２２００Ｂ）４．５ｇを添加し溶解した。溶解した液に、赤外染料を、バック面の塗布試料における赤外染料の吸収極大の吸光度が０．３５となるように添加し、さらにメタノール４３．２ｇに溶解したフッ素系活性剤（旭硝子社製、サーフロンＫＨ４０）４．５ｇとフッ素系活性剤（大日本インキ社製、メガファッグＦ１２０Ｋ）２．３ｇを添加して、溶解するまで十分に攪拌を行った。最後に、ＭＥＫに１質量％の濃度でディゾルバー型ホモジナイザーにて分散したシリカ（Ｗ．Ｒ．Ｇｒａｃｅ社製、シロイド６４Ｘ６０００）を７５ｇ添加、攪拌し、バック面の塗布液を調製した。
【０１７８】
《支持体の作製》
濃度０．１７０に青色着色したポリエチレンテレフタレートフィルムベース（厚み１７５μｍ）の片方の面に、０．５ｋＶ・Ａ・ｍｉｎ／ｍ²のコロナ放電処理を施した後、その上に下記の下引塗布液Ａを用いて下引層ａを、乾燥膜厚が０．２μｍになるように塗設した。更に、もう一方の面に同様に０．５ｋＶ・Ａ・ｍｉｎ／ｍ²のコロナ放電処理を施した後、その上に下記の下引塗布液Ｂを用い、下引層ｂを、乾燥膜厚が０．１μｍとなるように塗設した。その後、複数のロール群からなるフィルム搬送装置を有する熱処理式オーブンの中で、１３０℃にて１５分熱処理を行った。
【０１７９】
（下引塗布液Ａ）
ｎ−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％及び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、界面活性剤（ＵＬ−１）０．６ｇ及びメチルセルロース０．５ｇを混合した。更に、シリカ粒子（サイロイド３５０、富士シリシア社製）１．３ｇを水１００ｇに添加し、超音波分散機（ＡＬＥＸ Ｃｏｒｐｏｒａｔｉｏｎ（株）製、Ｕｌｔｒａｓｏｎｉｃ Ｇｅｎｅｒａｔｏｒ、周波数２５ｋＨｚ、６００Ｗ）にて３０分間分散処理した分散液を加え、最後に水で１０００ｍｌに仕上げて、下引塗布液Ａとした。
【０１８０】
【化２１】

【０１８１】
（コロイド状酸化スズ分散液の調製）
塩化第２スズ水和物６５ｇを、水／エタノール混合溶液２０００ｍｌに溶解して均一溶液を調製した。次いで、これを煮沸し、共沈殿物を得た。生成した沈殿物をデカンテーションにより取り出し、蒸留水にて数回水洗した。沈殿物を洗浄した蒸留水中に硝酸銀を滴下し、塩素イオンの反応がないことを確認後、洗浄した沈殿物に蒸留水を添加し、全量を２０００ｍｌとする。更に、３０％アンモニア水を４０ｍｌ添加し、水溶液を加温して、容量が４７０ｍｌになるまで濃縮してコロイド状酸化スズ分散液を調製した。
【０１８２】
（下引塗布液Ｂ）
前記コロイド状酸化スズ分散液３７．５ｇ、ｎ−ブチルアクリレート２０質量％、ｔ−ブチルアクリレート３０質量％、スチレン２７質量％及び２−ヒドロキシエチルアクリレート２８質量％の共重合体ラテックス液（固形分３０％）３．７ｇ、ｎ−ブチルアクリレート４０質量％、スチレン２０質量％、グリシジルメタクリレート４０質量％の共重合体ラテックス液（固形分３０％）１４．８ｇと界面活性剤ＵＬ−１の０．１ｇを混合し、水で１０００ｍｌに仕上げて下引塗布液Ｂとした。
【０１８３】
（感光層面側及びバック面側の塗布）
〔感光層面側の塗布〕
前記調製した各感光層塗布液２ａ、２ｂ、１ａ〜１ｇ及び表面保護層塗布液を用いて、支持体側から感光層及び表面保護層を、それぞれ押し出しコーターを用いて、同時重層塗布することにより銀塩光熱写真ドライイメージング材料試料Ｎｏ．１〜９を作製した。なお、感光層は１層塗布で、塗布銀量は１．８ｇ／ｍ²、また、乾燥温度７５℃、露点温度１０℃の乾燥風を用いて、５分間乾燥を行った。表面保護層は乾燥膜厚として１．４５μｍになる様に行った。
【０１８４】
〔バック面側の塗布〕
上記調製したバック面塗布液を、それぞれ乾燥膜厚が３μｍになるように押し出しコーターを用いて塗布、乾燥を行った。乾燥温度は１００℃、露点温度１０℃の乾燥風を用いて５分間かけて乾燥した。
【０１８５】
《銀塩光熱写真ドライイメージング材料の評価》
上記作製した銀塩光熱写真ドライイメージング材料試料Ｎｏ．１〜９について、以下の方法にて特性評価を行った。
【０１８６】
（カブリ及び感度の測定）
上記作製した各銀塩光熱写真ドライイメージング材料を半切りサイズに加工した後、各々の試料を８１０ｎｍの半導体レーザで像様露光を施した。なお、露光においては、試料の露光面と露光レーザ光の角度は８０度とし、また、レーザの出力は、７５ｍＷとし、高周波重畳を縦マルチモードで出力した。露光時間は１×１０^-7秒で露光した。熱現像処理は、ヒートドラムを用いて均一加熱を行い、処理条件は、１２３℃、１３．５秒で行った。以上のようにして作製した熱現像処理済み試料の濃度を光学濃度計（コニカ社製 ＰＤ−８２）で測定し、濃度Ｄと露光量Ｌｏｇ（１／Ｅ）からなる特性曲線を作製し、最小濃度（カブリ濃度）及び感度を測定した。なお、感度は最小濃度（カブリ濃度）より１．０高い濃度を与える露光量の逆数の対数を感度と定義した。写真特性値ガンマは、特性曲線の傾き（階調γ）を表す。ここでは、ガンマは（最小濃度＋０．２５）から（最小濃度＋２．５）の傾きを示す。なお、階調γ以外の結果は試料Ｎｏ．１を基準１００とする相対値で示す。
【０１８７】
（保存安定性の評価）
作製した銀塩光熱写真ドライイメージング材料（試料Ｎｏ．１〜９）を、内部が２５℃で相対湿度６０％に保たれた遮光性の密閉容器中にそれぞれ封入し、５５℃で７日間経時した。これを強制経時処理という。処理を施した各試料を、前記カブリ、感度の評価に用いたものと同じ露光及び熱現像を行い、測定した。なお、結果は試料Ｎｏ．１の即日試料を基準１００とする相対値で示す。
【０１８８】
【表２】

【０１８９】
【表３】

【０１９１】
参考例２
〔感光性ハロゲン化銀乳剤３の調製〕
参考例１の感光性ハロゲン化銀乳剤の調製工程において、核形成後の温度を４５℃から３０℃に変更した以外は全く感光性ハロゲン化銀乳剤１と同じにして感光性ハロゲン化銀乳剤３を調製した。この乳剤は平均粒子サイズ０．０４０μｍ粒子サイズの変動係数１１％、［１００］面比率９１％の立方体沃臭化銀粒子であった。
【０１９２】
感光性ハロゲン化銀乳剤３を上記参考例１に記載の感光性ハロゲン化銀乳剤１と同じように調製するが、化学増感は硫黄、セレン、金増感剤の代わりにＨｙｐｏと一般式（１−１）又は（１−２）の増感剤にしたことと、一般式（Ａ）の化合物を表４に示したように行った。これを感光性ハロゲン化銀乳剤Ｅｍ−３ａ〜３ｉとする。
【０１９３】
引き続き、これらの感光性ハロゲン化銀乳剤Ｅｍ−３ａ〜３ｉを参考例１の方法で感光性乳剤分散液から感光層塗布液が得られた。また、参考例１と同様な方法で塗布試料を作った。
【０１９４】
評価方法は参考例１と同様にして得た。なお、かぶり、感度は試料Ｎｏ．１０の即日試料を基準１００とする相対値で示す。
【０１９５】
【表４】

【０１９６】
【表５】

【０１９８】
実施例１
〔感光性ハロゲン化銀乳剤４の調製〕
参考例２の感光性ハロゲン化銀乳剤３の化学増感を施さないものを、感光性ハロゲン化銀乳剤４とする。参考例１の方法で感光性乳剤分散液４が得られた。
【０１９９】
（塗布液の調製）
安定剤液、赤外増感色素液、添加液ａ及び添加液ｂは参考例１で作製したものと同じものを使用した。
【０２００】
〔添加液Ｃの調製〕
表６のように一般式（Ｐ１）の化合物、３．４３ｇのフタラジンをＭＥＫ４０．９ｇに溶解し添加液Ｃとした。
【０２０１】
〔上層感光層塗布液Ｅｍ−４ａ〜４ｌの調製〕
前記感光性乳剤分散液４（５０ｇ）およびＭＥＫ１５．１１ｇを攪拌しながら１３℃に保温し、ｐＨ７にして、一般式（１−１）、（１−２）の化合物を表６のように加え、３０分攪拌した。その後かぶり抑制剤ビス（ジメチルアセトアミド）ジブロモブロメイト（１０％メタノール溶液）０．３２ｇを加え、１時間攪拌した。続いて、１０質量％のＣａＢｒ₂のメタノール溶液４ｍｌを添加し２０分間攪拌した。更に、安定剤液０．３４ｇを添加して１０分間攪拌した後、２．０ｇの赤外増感色素液を添加して１時間半攪拌した。その後、安定剤−３の０．２％メタノール溶液を２ｇ添加した。５分後、バインダー樹脂としてポリビニルアセタール樹脂Ｐ−１を１３．３１ｇ添加して３０分攪拌した後、テトラクロロフタル酸（９．４質量％ＭＥＫ溶液）１．０８４ｇを添加して１５分間攪拌した。さらに攪拌を続けながら、１．６ｍｌのＤｅｓｍｏｄｕｒＮ３３００／モーベイ社製の脂肪族イソシアネート（１０％ＭＥＫ溶液）、１２．４３ｇの添加液ａ、一般式（Ａ）の化合物を表６のように加え、その後、４．２７ｇの添加液Ｃを順次添加し攪拌することにより感光層塗布液Ｅｍ−４ａ〜Ｅｍ−４ｌを得た。
【０２０２】
〔下層感光層塗布液Ｅｍ−５ａ〜５ｃの調製〕
前記感光性乳剤分散液４（５０ｇ）およびＭＥＫ１５．１１ｇを攪拌しながら１３℃に保温し、ビス（ジメチルアセトアミド）ジブロモブロメイト（１０％メタノール溶液）０．３２ｇを加え、１時間攪拌した。続いて、安定剤液０．３４ｇを添加して１０分間攪拌した後、２．０ｇの赤外増感色素液を添加して１時間半攪拌した。その後、安定剤−３の０．２％メタノール溶液を２ｇ添加した。５分後、バインダー樹脂としてポリビニルアセタール樹脂Ｐ−１を１３．３１ｇ添加して３０分攪拌した後、テトラクロロフタル酸（９．４質量％ＭＥＫ溶液）１．０８４ｇを添加して１５分間攪拌した。さらに攪拌を続けながら、１２．４３ｇの添加液ａ、１．６ｍｌのＤｅｓｍｏｄｕｒＮ３３００／モーベイ社製の脂肪族イソシアネート（１０％ＭＥＫ溶液）、４．２７ｇの添加液ｂ、表６に示したように省銀化剤（１０％ＭＥＫ溶液）を順次添加し攪拌することにより感光層塗布液Ｅｍ−５ａ〜Ｅｍ−５ｃを得た。
【０２０３】
〔感光層面側の塗布〕
前記調製した各感光層塗布液及び各表面保護層塗布液を用いて、支持体側から感光層下層、感光層上層及び表面保護層を、それぞれ押し出しコーターを用いて、同時重層塗布することにより銀塩光熱写真ドライイメージング材料試料Ｎｏ．１９〜３０を作製した。なお、塗布銀量は１ｇ／ｍ²、試料Ｎｏ．１９〜Ｎｏ．３０の感光層は２層塗布で、下層（下引き層、支持体側）が塗布銀量として０．３３ｇ／ｍ²、感光層上層（表面保護層側）が塗布銀量として０．６７ｇ／ｍ²、また、乾燥温度７５℃、露点温度１０℃の乾燥風を用いて、５分間乾燥を行った。表面保護層が乾燥膜厚として１．４５μｍになる様に行った。
【０２０４】
評価方法は参考例１と同様にして得た。なお、かぶりと感度は試料Ｎｏ．１９の即日試料を基準１００とする相対値で示す。
【０２０５】
（画像保存性の評価）
センシトメトリー評価と同様の処理をした２枚の試料を１枚は２５℃、５５％で７日間遮光保存し、もう１枚は４０℃、５５％で７日間色温度７７００ケルビン、照度１１６００ルクスの光源台で晒した後、両者のカブリ部分の濃度を測定した。結果を表７に示す。
【０２０６】
カブリの増加＝光に晒した後のカブリ−遮光保存したときのカブリにより画像保存性を評価した。なお、結果は試料Ｎｏ．１９を基準１００とする相対値で示す。
【０２０７】
（銀色調の評価）
上記の方法で露光現像した。試料の現像後の濃度が１．１±０．０５になるように露光現像した試料を作製した。光学濃度Ｄ＝１．１±０．０５におけるＪＩＳ Ｚ ８７２９で規定される色相角ｈ_abにより求められる。
【０２０８】
評価基準はｈ_abの範囲が、
◎：２００°＜ｈ_ab＜２５０°
○：１９５°＜ｈ_ab＜１９９°、２５１°＜ｈ_ab＜２５５°
△：１９０°＜ｈ_ab＜１９４°、２５６°＜ｈ_ab＜２６０°
×：ｈ_ab＜１８９°、２６１°＜ｈ_ab
【０２０９】
【表６】

【０２１０】
【表７】

【０２１１】
表７より明らかなように、本発明の構成を有する試料は、比較品に対し、カブリ濃度が低く、十分な感度があり、銀色調も優れている。しかも、階調もよく優れた医用感光感材である。かつ銀塩光熱写真ドライイメージング材料の現像前の保存安定性、現像後の画像保存性共に良好であることがわかる。
【０２１２】
【発明の効果】
本発明により、高感度でカブリが低く、画像の保存性が優れ、保存安定性が良好なレーザイメージャー用及びイメージセッター出力フィルム用銀塩光熱写真ドライイメージング材料とその画像形成方法を提供することができた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silver salt photothermographic dry imaging material having high image quality and excellent storability, and particularly to a black and white silver salt photothermographic dry imaging material having high image quality and excellent storability of a developed silver image.
[0002]
[Prior art]
Conventionally, in the medical and printing plate making fields, waste liquids resulting from wet processing of image forming materials have been a problem in terms of workability. In recent years, the amount of waste processing liquids has been strongly reduced from the viewpoint of environmental conservation and space saving. It is desired.
[0003]
Therefore, there has been a need for a technique relating to silver salt photothermographic dry imaging materials for photographic technology that can be efficiently exposed by a laser imager or a laser image setter and can form a clear black image with high resolution. Such a silver salt photothermographic dry imaging material is disclosed in, for example, D.I. Morgan and B.M. U.S. Pat. Nos. 3,152,904, 3,457,075, or D. by Shery. H. As described in "Dry Silver Photographic Materials" by Klosterboer (Handbook of Imaging Materials, Marc Dekker, Inc., page 48, 1991) and the like. Silver salt photothermographic dry imaging materials containing salt, photosensitive silver halide, and reducing agent are known. Since this silver salt photothermographic dry imaging material does not use any solution processing chemicals, it is possible to provide a user with a simpler system that does not damage the environment.
[0004]
Among these, the silver salt photothermographic dry imaging material in which each of the above compounds is not added when the amount of silver applied per unit area is the same by adding a compound called a contrast enhancer or a silver saving agent. A silver salt photothermographic dry imaging material capable of obtaining a high concentration as compared with is proposed.
[0005]
Examples of the silver salt photothermographic dry imaging material include, for example, US Pat. Nos. 5,496,695, 5,545,505, 5,545,507, and 5,637,449. 5,654,130, 5,635,339, 5,545,515, 5,686,228, JP-A-10-339929, 11-84576, 11-95365, 11-95366, 11-109546, 11-119372, 11-119373, JP-A 2000-356834, JP-A 2001-27790, etc. Describes compounds as various contrast enhancing agents or silver saving agents (hereinafter referred to as silver saving agents).
[0006]
However, the silver salt photothermographic dry imaging material incorporating a silver-saving agent has different color density in the unexposed area after development depending on the storage conditions of the silver salt photothermographic dry imaging material before thermal development. There was a problem of not coming out. In addition, the compounds described in each of the above-mentioned patents are generally advantageous for images that require contrast because they are easy to achieve hard gradation (high gamma), but like medical images. For applications that require delicate gradation, it is a compound that is difficult to use in some cases.
[0007]
[Problems to be solved by the invention]
The object of the present invention is a silver salt photothermographic dry imaging material for laser imagers and imagesetter output films having high sensitivity, low fog, high maximum density, excellent image sharpness and good storage stability, and its An object is to provide an image forming method.
[0008]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitutions.
[0009]
  1. Silver salt photothermographic dry imaging having a layer containing a photosensitive emulsion containing at least a non-photosensitive aliphatic carboxylic acid silver salt and a photosensitive silver halide, a silver ion reducing agent, a binder, and a crosslinking agent on a support In the material, at least one of the silver halides is pH 6-10And in the presence of the compound represented by the general formula (P1)A silver salt photothermographic dry imaging material characterized by being chemically sensitized with
[0013]
  2. A silver halide emulsion having two or more photosensitive emulsion layers containing a photosensitive emulsion and having a photosensitive emulsion layer adjacent to the support.Alkoxysilane compound having two or more primary or secondary amino groups or a salt thereofIt is characterized by containingSaid 1Silver salt photothermographic dry imaging material.
[0014]
  3. The image is developed at a development temperature of 123 ° C. and a development time of 13.5 seconds, and the obtained image is equal in unit length of logarithm Log (1 / E) (X axis) of the optical density D (Y axis) and the inverse of the exposure amount. When shown as a characteristic curve on Cartesian coordinates, the optical tone has an average gradation of 0.25 to 2.5 in the range of 2.5 to 5.0 and the maximum density of 3.0 to 4.5. Characterized bySaid 1 or 2Silver salt photothermographic dry imaging material.
[0015]
  4. 1 to3An image forming method comprising exposing the silver salt photothermographic dry imaging material according to any one of the above to a 600 to 900 nm red light to infrared laser to form an image.
[0016]
  5. The exposure is performed by a laser scanning exposure machine in which the angle formed between the exposure surface and the scanning laser beam is not substantially perpendicular.4The image forming method described.
[0017]
  6. The scanning laser beam is exposed by a laser scanning exposure machine that is a vertical multi-beam.4The image forming method described.
[0018]
  7. 1 to3An image forming method, wherein the silver salt photothermographic dry imaging material according to any one of the above is heated and developed at a temperature of 80 ° C. or higher and 200 ° C. or lower after exposure.
[0019]
The present invention will be described in more detail. First, the photosensitive silver halide according to the present invention will be described. The silver halide functions as an optical sensor, and preferably has a small grain size in order to keep white turbidity after image formation low and to obtain good image quality. The average particle size is 0.08 μm or less, preferably 0.01 μm to 0.08 μm, particularly preferably 0.02 μm to 0.06 μm. The content of silver halide having a small grain size is preferably 70% or more. Slightly larger particles are preferred for sensitivity and tone adjustment. The average particle size is 0.1 μm or less, preferably 0.04 μm to 0.1 μm, and particularly preferably 0.05 μm to 0.08 μm. The content is preferably 30% or less.
[0020]
Further, the shape of the silver halide is not particularly limited, and examples thereof include cubic and octahedral so-called normal crystals and non-normal crystals such as spherical, rod-like, 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.
[0021]
The amount of silver halide is preferably 3% to 7%, more preferably 5% to 7%, in terms of silver ratio, based on the non-photosensitive organic silver salt described below.
[0022]
The silver halide used in the present invention preferably contains metal ions belonging to Groups 6 to 11 of the periodic table on the surface from 1/2 of the grain volume. As the metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable. Particularly preferred are Fe, Co, Ru, Rh, Re, Os, and Ir. It is preferable that at least one of these metal ions is contained on the surface from 3/5 of the silver halide grain volume, and more preferably, equimolar metal ions are contained on the surface from 3/4 of the volume.
[0023]
These metal ions can be introduced into the silver halide in the form of metal complexes or metal complex ions. As these metal complexes or metal complex ions, hexacoordinate metal complexes represented by the following general formula are preferable.
[0024]
General formula [ML₆]^m
In the formula, M represents a transition metal selected from Group 6 to 11 elements of the periodic table, L represents a ligand, and m represents 0,-, 2-, 3-, or 4-. Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aco. A ligand, nitrosyl, thionitrosyl and the like can be mentioned, and ako, nitrosyl, thionitrosyl and the like are preferable. When an acoligand is present, it preferably occupies one or two of the ligands. L may be the same or different.
[0025]
Specific preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).
[0026]
Although the specific example of a transition metal complex ion is shown below, this invention is not limited to these.
[0027]
1: [RhCl₆]^3-
2: [RuCl₆]^3-
3: [ReCl₆]^3-
4: [RuBr₆]^3-
5: [OsCl₆]^3-
6: [IrCl₆]^Four-
7: [Ru (NO) Cl_Five]^2-
8: [RuBr_Four(H₂O)]^2-
9: [Ru (NO) (H₂O) Cl_Four]^-
10: [RhCl_Five(H₂O)]^2-
11: [Re (NO) Cl_Five]^2-
12: [Re (NO) (CN)_Five]^2-
13: [Re (NO) Cl (CN)_Four]^2-
14: [Rh (NO)₂Cl_Four]^-
15: [Rh (NO) (H₂O) Cl_Four]^-
16: [Ru (NO) (CN)_Five]^2-
17: [Fe (CN)₆]^3-
18: [Rh (NS) Cl_Five]^2-
19: [Os (NO) Cl_Five]^2-
20: [Cr (NO) Cl_Five]^2-
21: [Re (NO) Cl_Five]^-
22: [Os (NS) Cl_Four(TeCN)]^2-
23: [Ru (NS) Cl_Five]^2-
24: [Re (NS) Cl_Four(SeCN)]^2-
25: [Os (NS) Cl (SCN)_Four]^2-
26: [Ir (NO) Cl_Five]^2-
27: [Ir (NS) Cl_Five]^2-
One kind of these metal ions, metal complexes or metal complex ions may be used, or two or more kinds of the same and different metals may be used in combination. The content of these metal ions, metal complexes or metal complex ions is generally 1 × 10 5 per mole of silver halide.^-9~ 1x10^-2Molar is suitable, preferably 1 × 10^-8~ 1x10^-FourIs a mole.
[0028]
The compounds providing these metals are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, chemical sensitization It may be added at any stage before or after, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and most preferably at the stage of nucleation. Add in stages.
[0029]
In addition, it may be added in several divided portions, or it can be uniformly contained in the silver halide grains. JP-A-63-29603, JP-A-2-306236, 3-167545 No. 4-76534, No. 6-110146, No. 5-273683, and the like. Preferably, a distribution can be provided inside the particles.
[0030]
These metal compounds can be added by dissolving in water or an appropriate organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble silver salt solution or water-soluble halide solution during particle formation, or the silver salt solution and the halide solution are mixed simultaneously. When adding a third aqueous solution, a method of preparing silver halide grains by a method of simultaneous mixing of three liquids, a method of introducing an aqueous solution of a required amount of a metal compound into a reaction vessel during grain formation, or a silver halide preparation There is a method of adding and dissolving another silver halide grain which has been previously doped with metal ions or complex ions. In particular, a method of adding an aqueous solution of a metal compound powder or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble halide solution.
[0031]
When added to the particle surface, a necessary amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particle, during or after physical ripening, or at the time of chemical ripening.
[0032]
In the present invention, the photosensitive silver halide grains may or may not be desalted after grain formation. However, when desalting is performed, methods known in the art such as a noodle method and a flocculation method are used. It can be desalted by washing with water.
[0033]
As a method for preparing a silver halide emulsion containing light-sensitive silver halide grains according to the present invention, P.I. Chifie et Physique Photographic (published by Paul Montel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. There are methods described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al, and the silver halide emulsion used in the present invention can be prepared using these methods. That is, any of an acidic method, a neutral method, an ammonia method, and the like may be used, and a method of reacting a soluble silver salt and a soluble halogen salt may be any one of a one-side mixing method, a simultaneous mixing method, a combination thereof, and the like. Good. Typically, a silver halide emulsion is prepared by mixing a silver salt aqueous solution and a halide aqueous solution in a protective colloid solution (a hydrophilic colloid such as gelatin is used) as a reaction mother liquor, and nucleating and crystal growth. The double jet method is generally used as a method for adding a halide aqueous solution or a silver salt aqueous solution. Among these, the controlled double jet method in which each component is mixed while controlling pAg and pH to perform the nucleation and crystal growth is representative. In addition, it includes various variations such as a method in which seed particles are first prepared (nucleated), and then this growth is performed under the same conditions or under different conditions (crystal growth or ripening). Yes. In short, it is well known in the art to control the crystal habit and size in various ways by defining the mixing conditions of the silver salt aqueous solution and the halide aqueous solution in the mixing step in the protective colloid aqueous solution. Subsequent to these mixing steps, a desalting step is performed to remove excess salts from the prepared emulsion. As a desalting step, there is a flocculation method in which a silver halide grain is coagulated and precipitated together with gelatin as a protective colloid by adding a flocculant to the prepared silver halide emulsion, and this is separated from a supernatant containing salts. well known. The supernatant liquid is removed by decantation, and dissolution, flocculation, and decantation are repeated in order to remove excess salts contained in the gelatin coagulate containing the silver halide grains that have been aggregated and settled. A method of removing soluble salts by ultrafiltration is also well known. This is a method of removing unnecessary low-molecular weight salts by using an ultrafiltration membrane, using a synthetic membrane that does not transmit large-sized grains such as silver halide grains and gelatin, and molecules having a large molecular weight.
[0034]
The hydrophilic colloid contained in the photosensitive silver halide in the present invention is preferably 40 g or less per 1 mol of silver. Particularly preferably, it is 35 g or less.
[0035]
Furthermore, in the present invention, the hydrophilic colloid is 6 × 10 6 to 1 mol of a transition metal selected from the elements of Groups 6 to 11 of the periodic table of elements contained in the silver halide grains.^-6g or more is preferable.
[0036]
That is, the hydrophilic colloid and the transition metal contained in the photosensitive silver halide of the present invention preferably satisfy the above conditions.
[0037]
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. . Regarding the method and procedure of this chemical sensitization, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850, JP-A Nos. 51-22430, 51-78319, No. 51-81124. In order to achieve sensitization, as described in US Pat. No. 3,980,482, when a part of the organic silver salt is converted to photosensitive silver halide by the silver halide forming component. In addition, an amide compound having a low molecular weight may coexist.
[0038]
In the present invention, a more preferred embodiment is that the pH of all the steps for forming the photosensitive silver halide is 3 to 6, preferably 4 to 6.
[0039]
Separately prepared photosensitive silver halide grains can be desalted by known desalting methods such as noodle method, flocculation method, ultrafiltration method, electrodialysis method, etc., but silver salt photothermographic dry imaging The material can be used without desalting.
[0040]
Next, the determination of the transition metal in the photosensitive silver halide will be described. The concentration distribution of the transition metal in the silver halide grains can be determined by dissolving the grains little by little from the surface to the inside and measuring the content of the transition metal in each part. Specific examples include the methods described below.
[0041]
Prior to quantification of the transition metal, the silver halide emulsion is pretreated as follows. First, 50 ml of 0.2% actinase aqueous solution is added to about 30 ml of the emulsion, and the mixture is stirred at 40 ° C. for 30 minutes for gelatin degradation. This operation is repeated 5 times. After centrifugation, washing is repeated 5 times with 50 ml of methanol, 2 times with 50 ml of 1 M / L nitric acid, and 5 times with ultrapure water. After centrifugation, only the silver halide is separated. The surface portion of the obtained silver halide grains is dissolved by an aqueous ammonia solution or ammonia whose pH is adjusted (the ammonia concentration and pH are changed according to the type and amount of dissolution of silver halide). As a method for dissolving the extreme surface of silver bromide grains in silver halide, about 3% of the grain surface can be dissolved using 20 ml of about 10% aqueous ammonia solution per 2 g of silver halide. At this time, the amount of silver halide dissolved is determined by centrifuging the aqueous ammonia solution and silver halide after dissolution of the silver halide, and determining the amount of silver present in the resulting supernatant by a high frequency induction plasma mass spectrometer. (ICP-MS) It can be quantified by a high frequency induction plasma emission spectrometer (ICP-AES) or by atomic absorption. The amount of transition metal per mole of silver halide present at about 3% of the grain surface is determined from the difference between the amount of metal contained in the silver halide after surface dissolution and the total amount of transition metal in the silver halide that does not dissolve. be able to. Examples of the determination method of the transition metal include an ICP-MS method, an ICP-AES method, or an atomic absorption method in which the solution is dissolved in an ammonium thiosulfate aqueous solution, a sodium thiosulfate aqueous solution, or a potassium cyanide aqueous solution and is matrix-matched. Of these, when potassium cyanide is used as a solvent and ICP-MS (manufactured by FSON Elemental Analysis) is used as an analyzer, about 40 mg of silver halide is dissolved in 5 ml of 0.2 M / L potassium cyanide, and the internal standard is 10 ppb. An elemental Cs solution is added, and a sample volume of 100 ml with ultrapure water is used as a measurement sample. Then, the transition metal in the measurement sample is quantified by ICP-MS using a calibration curve in which the matrix is combined with the transition metal-free silver halide. At this time, the exact amount of silver in the measurement sample can be quantified by ICP-AES or atomic absorption of a measurement sample diluted 100 times with ultrapure water. After such dissolution of the grain surface, the silver halide grains are washed with ultrapure water, and then the dissolution of the grain surface is repeated in the same manner as described above, thereby making the transition in the internal direction of the silver halide grains. The amount of metal can be quantified.
[0042]
The transition metal doped in the outer peripheral region of the silver halide grains used in the present invention can be quantified by combining the above-mentioned transition metal quantification method with well-known grain observation with an electron microscope.
[0043]
When a plurality of metals are used as the transition metal, the total number of transition metal contents described above is counted in mol.
[0044]
  Next, the present inventionThe following can be preferably used inThe compounds represented by formulas (1-1) and (1-2) will be described.
[Chemical B]

  Where Z ₁ , Z ₂ And Z _Three Are each an aliphatic group, an aromatic group, a heterocyclic group, -OR ₇ , -NR ₈ (R ₉ ), -SR _Ten , -SeR ₁₁ Represents a halogen atom or a hydrogen atom. R ₇ , R _Ten And R ₁₁ Each represents an aliphatic group, an aromatic group, a heterocyclic group, a hydrogen atom or a cation; ₈ And R ₉ Each represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom. Z ₁ And Z ₂ , Z ₂ And Z _Three , Z _Three And Z ₁ And may form a ring with each other. Chalcogen represents sulfur, selenium or tellurium. P represents a phosphorus atom.
[C]

  Where Z _Four And Z _Five Are each an alkyl group, an alkenyl group, an aralkyl group, an aryl group, a heterocyclic group, -NR ₁ (R ₂ ), -OR _Three Or -SR _Four Represents. R ₁ , R ₂ , R _Three And R _Four May be the same or different and each represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group. However, R ₁ And R ₂ May be a hydrogen atom or an acyl group. Z _Four And Z _Five May form a ring. Chalcogen represents sulfur, selenium, or tellurium.
[0045]
Z₁, Z₂, Z_Three, R₇, R₈, R₉, R_TenAnd R₁₁Is a linear, branched or cyclic alkyl group, alkenyl group, alkynyl group, aralkyl group (for example, methyl group, ethyl group, n-propyl group, isopropyl group, t-butyl group, n -Butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopentyl group, cyclohexyl group, allyl group, 2-butenyl group, 3-pentenyl group, propargyl group, 3-pentynyl group, benzyl group, phenethyl Group). Z₁, Z₂, Z_Three, R₇, R₈, R₉, R_TenAnd R₁₁The aromatic group represented by is a monocyclic or condensed aryl group (for example, phenyl group, pentafluorophenyl group, 4-chlorophenyl group, 3-sulfophenyl group, α-naphthyl group, 4-methylphenyl group) Represents. Z₁, Z₂, Z_Three, R₇, R₈, R₉, R_TenAnd R₁₁Is a 3 to 10-membered saturated or unsaturated heterocyclic group containing at least one of a nitrogen atom, an oxygen atom or a sulfur atom (for example, a pyridyl group, a thienyl group, a furyl group, Thiazolyl group, imidazolyl group, and benzimidazolyl group). R₇, R_TenAnd R₁₁The cation represented by X represents an alkali metal atom or ammonium, and the halogen atom represented by X represents, for example, a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. In general formula (1-1), preferably Z₁, Z₂Or Z_ThreeIs an aliphatic group, aromatic group or -OR₇And R₇Is an aliphatic group or an aromatic group. Z₁And Z₂, Z₂And Z_Three, Z_ThreeAnd Z₁And may form a ring with each other. Chalcogen represents a sulfur atom, a selenium atom or a tellurium atom.
[0046]
In the general formula (1-2), Z_FourAnd Z_FiveAre each an alkyl group (for example, methyl group, ethyl group, t-butyl group, adamantyl group, t-octyl group), alkenyl group (for example, vinyl group, propenyl group), aralkyl group (for example, benzyl group, phenethyl group). ), Aryl group (for example, phenyl group, pentafluorophenyl group, 4-chlorophenyl group, 3-nitrophenyl group, 4-octylsulfamoylphenyl group, α-naphthyl group), heterocyclic group (for example, pyridyl group, Thienyl, furyl, imidazolyl), -NR₁(R₂), -OR_ThreeOr -SR_FourRepresents. R₁, R₂, R_ThreeAnd R_FourEach may be the same or different and each represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group. As an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, Z in the general formula (1-1)₁The same example is given. However, R₁And R₂Is a hydrogen atom or an acyl group (for example, acetyl group, propanoyl group, benzoyl group, heptafluorobutanoyl group, difluoroacetyl group, 4-nitrobenzoyl group, α-naphthoyl group, 4-trifluoromethylbenzoyl group). May be. Z_FourAnd Z_FiveMay form a ring. Chalcogen represents sulfur, selenium, or tellurium.
[0047]
The chalcogen sensitizer represented by the general formula (1-1) or (1-2) reacts with silver ions to form sensitization nuclei in silver halide grains without involving the presence of an oxidizing agent. Can be chemically sensitized.
[0048]
  The present inventionRepresented by the above general formulas (1-1) and (1-2)The amount of chalcogen sensitizer used is not uniform depending on the type of chalcogen sensitizer used, silver halide grains, chemical sensitization environment, etc., but is generally about 10 per mol of the total amount of silver halide and organic silver.^-8-10^-2Moles are preferred, more preferably 10^-Five-10^-3Is a mole. As chemical sensitization environment in this invention, pH is 6-10, More preferably, it is 7-8. The temperature is preferably 30 to 65 ° C., more preferably 40 to 55 ° C. in the case of a silver halide emulsion dispersed in an aqueous gelatin solution. In a silver halide / organic silver emulsion containing a silver halide in an organic solvent, the temperature is preferably 8 to 30 ° C, more preferably 10 to 25 ° C, and still more preferably 13 to 20 ° C. In addition, when a silver halide solvent such as thiocyanate is present as in the prior art, silver ions on the surface of the silver halide increase, and the speed of chemical sensitization can be accelerated. Similarly, corrosive substances such as dibromobromate compounds (HBr [Br₂] -Containing compounds such as pyridine dibromobromate, bis (dimethylacetamide) dibromobromate) and halogen compounds (eg FeBr)_Three, FeCl_Three) Or halogen (eg Br₂) And acids (for example, hydrochloric acid and acetic acid) can also be used.
[0049]
  In the present invention,Represented by the above general formulas (1-1) and (1-2)Two or more chalcogen sensitizers may be used,theseIn addition to the chalcogen sensitizer, a known chemical sensitizer may be used. For example,Represented by the above general formulas (1-1) and (1-2)When the chalcogen in the chalcogen sensitizer is sulfur, selenium or tellurium, a known sulfur sensitizer, selenium sensitizer, tellurium sensitizer, reduction sensitizer or noble metal sensitizer is used in combination. Is preferred.
[0050]
  Represented by the above general formulas (1-1) and (1-2)Chalcogen sensitizers should be dissolved in an appropriate organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, methyl cellosolve, etc. Can do. In addition, using a well-known emulsification dispersion method, it is dissolved using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically emulsified and dispersed. An object can be made and used. Alternatively, a chalcogen sensitizer powder may be dispersed in water by a ball mill, a colloid mill, or ultrasonic waves by a method known as a solid dispersion method.
[0051]
The compounds represented by the general formulas (1-1) and (1-2) can be synthesized by ordinary methods well known to those skilled in the art.
[0052]
Specific examples of the compounds represented by the general formulas (1-1) and (1-2) are shown below, but the present invention is not limited thereto.
[0053]
[Formula 4]

[0054]
[Chemical formula 5]

[0055]
[Chemical 6]

[0056]
  Next, used in the present inventionfollowingThe compound represented by formula (A) will be described.
  Formula (A) R ¹ -R ² -AM or R ¹ -R ² = A
Where R ¹ And R ² Represents an aliphatic group, an aromatic group, a heterocyclic group, or an atomic group that can be bonded to each other to form a ring. Also R ¹ , R ² May be the same or different. However, R ² Represents a divalent or trivalent group. A represents a sulfur atom, a selenium atom or a tellurium atom. M represents a hydrogen atom, a metal atom, a quaternary ammonium group or a phosphonium group.
  In the general formula (A), R¹And R²Examples of the aliphatic group represented by the formula include a linear or branched alkyl, alkenyl, alkynyl or cycloalkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specifically, for example, methyl, ethyl, propyl, butyl, hexyl, decyl, dodecyl, isopropyl, t-butyl, 2-ethylhexyl, allyl, 2-butenyl, 7-octenyl, propargyl, 2-butynyl, cyclopropyl, cyclopentyl , Cyclohexyl, cyclododecyl and the like. R¹And R²Examples of the aromatic group represented by are those having 6 to 20 carbon atoms, and specifically include groups such as phenyl, naphthyl, and anthranyl. R¹And R²The heterocyclic group represented by may be a monocyclic ring or a condensed ring, and includes a 5- to 6-membered heterocyclic group having at least one of O, S, and N atoms and an amine oxide group in the ring. Specifically, for example, pyrrolidine, piperidine, tetrahydrofuran, tetrahydropyran, oxirane, morpholine, thiomorpholine, thiopyran, tetrahydrothiophene, pyrrole, pyridine, furan, thiophene, imidazole, pyrazole, oxazole, thiazole, isoxazole, isothiazole, triazole, And groups derived from tetrazole, thiadiazole, oxadiazole, and these benzerogues. R¹And R²Examples of those that form a ring include 4-membered to 7-membered rings. Preferably it is a 5-7 membered ring. R¹And R²Preferred groups are a heterocyclic group and an aromatic group, more preferably a heteroaromatic group. R¹And R²The aliphatic group, aromatic group or heterocyclic group represented by formula (1) may be further substituted with a substituent, such as a halogen atom (for example, a chlorine atom or a bromine atom), an alkyl group (for example, a methyl group) , Ethyl group, isopropyl group, hydroxyethyl group, methoxymethyl group, trifluoromethyl group, t-butyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), aralkyl group (eg benzyl group, 2-phenethyl) Group), aryl group (eg phenyl group, naphthyl group, p-tolyl group, p-chlorophenyl group etc.), alkoxy group (eg methoxy group, ethoxy group, isopropoxy group, butoxy group etc.), aryloxy group (eg Phenoxy group, 4-methoxyphenoxy group, etc.), cyano group, acylamino group (for example, acetylamino) , Propionylamino group etc.), alkylthio group (eg methylthio group, ethylthio group, butylthio group etc.), arylthio group (eg phenylthio group, p-methylphenylthio group etc.), sulfonylamino group (eg methanesulfonylamino group, benzenesulfonyl) Amino group), ureido group (eg, 3-methylureido group, 3,3-dimethylureido group, 1,3-dimethylureido group, etc.), sulfamoylamino group (dimethylsulfamoylamino group, diethylsulfamoyl) Amino group, etc.), carbamoyl group (eg methylcarbamoyl group, ethylcarbamoyl group, dimethylcarbamoyl group etc.), sulfamoyl group (eg ethylsulfamoyl group, dimethylsulfamoyl group etc.), alkoxycarbonyl group (eg methoxycarbonyl group, Toxylcarbonyl group etc.), aryloxycarbonyl group (eg phenoxycarbonyl group, p-chlorophenoxycarbonyl group etc.), sulfonyl group (eg methanesulfonyl group, butanesulfonyl group, phenylsulfonyl group etc.), acyl group (eg acetyl group, Propanoyl group, butyroyl group etc.), amino group (methylamino group, ethylamino group, dimethylamino group etc.), hydroxy group, nitro group, nitroso group, amine oxide group (eg pyridine-oxide group etc.), imide group (eg Phthalimide group, etc.), disulfide groups (eg, benzene disulfide group, benzthiazolyl-2-disulfide group, etc.), and heterocyclic groups (eg, pyridyl group, benzimidazolyl group, benzthiazolyl group, benzoxazolyl group, etc.). R¹And R²May have one or more of these substituents. Further, each substituent may be further substituted with the above-described substituent. R¹And R²May be the same or different.
[0057]
Specific examples of the compound represented by formula (A) used in the present invention are shown below, but the present invention is not limited to these.
[0058]
[Chemical 7]

[0059]
[Chemical 8]

[0060]
[Chemical 9]

[0061]
The compound represented by the general formula (A) can be added to the emulsion at any step during silver salt grain formation, before or after chemical ripening, and immediately before coating. The preferred addition time is after chemical sensitization and immediately before coating. The preferred addition amount is 1 × 10^-Five˜1 mol / Ag mol, more preferably 1 × 10^-3˜1 × 0.1 mol / Ag mol.
[0062]
In the general formula (P1), X_Five, X₆, X₇And X₈Is a fluorine atom, chlorine atom, bromine atom or iodine atom which may be the same or different from each other, preferably a chlorine atom, bromine atom or iodine atom, more preferably a chlorine atom or bromine atom. An atom, particularly preferably a bromine atom.
[0063]
B₁And B₂Each independently represents a hydrogen atom, a halogen atom or a substituent. Examples of the substituent include an alkyl group, an aryl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an amino group, an acyl group, and an acyloxy group. Group, acylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, sulfonyl group, alkylsulfonyl group, sulfinyl group, cyano group, heterocyclic group and the like. p represents an integer of 1 to 3.
[0064]
G₁And G₂Represents a linking group, and examples of the linking group include -SO.₂-, -CO-, -NHCO-, -OOC-, -N (R₈) SO₂In addition, a linking group may be formed by bonding to a group selected from —S—, —NH—, —CO—, and —O— via an alkyl group. R₈Represents a substituent. R₈As the substituent represented by R 1 in the general formula (1-1),₈The same thing as the substituent represented by these is mentioned. G₁And G₂May be the same or different. However, G₁And G₂-SO together₂In the case of-, p represents 2 or 3.
[0065]
J represents an alkylene group, a cycloalkylene group, an alkenylene group, an alkynylene group, or a p + 1 valent group derived from these groups. Preferably, it is an alkylene group having 2 to 20 carbon atoms in total, a cycloalkylene group, or a p + 1 valent group derived from these groups, and particularly preferably an alkylene group having 2 to 10 carbon atoms in total, a cycloalkylene group, or It is a p + 1 valent group derived from each of these groups. These groups may further have a substituent. Examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkyl group (for example, a methyl group, an ethyl group, a propyl group, Butyl group, pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, etc.), cycloalkyl group (for example, cyclohexyl group, cycloheptyl group, etc.), alkenyl group (for example, ethenyl-2- Propenyl group, 3-butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, etc.), cycloalkenyl group (for example, 1-cycloalkenyl group, 2-cycloalkenyl group) Etc.), alkynyl groups (for example, ethynyl group, 1-propynyl group, etc.), alkoxy groups (for example, methoxy group, ethoxy group, propoxy group) ), Alkylcarbonyloxy group (for example, acetyloxy group, etc.), alkylthio group (for example, methylthio group, trifluoromethylthio group, etc.), carboxy group, alkylcarbonylamino group (for example, acetylamino group, etc.), ureido group (for example, , Methylaminocarbonylamino group etc.), alkylsulfonylamino group (eg methanesulfonylamino group etc.), alkylsulfonyl group (eg methanesulfonyl group, trifluoromethanesulfonyl group etc.), carbamoyl group (eg carbamoyl group, N, N-dimethylcarbamoyl group, N-morpholinocarbonyl group, etc.), sulfamoyl group (sulfamoyl group, N, N-dimethylsulfamoyl group, N-morpholinosulfonylsulfamoyl group, etc.), trifluoromethyl group, hydroxy group Nitro group, cyano group, alkylsulfonamide group (for example, methanesulfonamide group, butanesulfonamide group, etc.), alkylamino group (for example, amino group, N, N-dimethylamino group, N, N-diethylamino group, etc.), Sulfo group, phosphono group, sulfite group, sulfino group, alkylsulfonylaminocarbonyl group (for example, methanesulfonylaminocarbonyl group, ethanesulfonylaminocarbonyl group, etc.), alkylcarbonylaminosulfonyl group (for example, acetamidosulfonyl group, methoxyacetamidosulfonyl) Group), alkylcarbonylaminocarbonyl group (eg, acetamidocarbonyl group, methoxyacetamidocarbonyl group, etc.), alkylsulfinylaminocarbonyl group (eg, methanesulfinylaminocarbonyl group). A sulfonyl group, an ethanesulfinylaminocarbonyl group, and the like). Moreover, when there are two or more substituents, they may be the same or different. However, an aryl group or a heteroaryl group is not included as a part of the substituent.
[0066]
Although the specific example of a compound represented by general formula (P1) of this invention below is given, this invention is not limited to these.
[0067]
[Chemical Formula 10]

[0068]
Embedded image

[0069]
Embedded image

[0070]
Embedded image

[0071]
The addition layer of the compound represented by the general formula (P1) can be added to either a photosensitive layer containing a silver halide emulsion or a non-photosensitive layer, and is a layer adjacent to the photosensitive layer and / or the photosensitive layer. Is preferred. Further, when the compound represented by the general formula (P1) is added to the silver salt photothermographic dry imaging material, the addition amount is not particularly limited, but is generally 10 per mol of silver halide.^-FourThe molar ratio is preferably about 1.0 to 1.0 mol.^-3A range of from mol to 0.3 mol is particularly preferred.
[0072]
In the present invention, an alkoxysilane compound having two or more primary or secondary amino groups as described in Japanese Patent Application No. 2001-192698 or a salt thereof may be contained as a silver saving agent. preferable.
[0073]
Here, having two or more primary or secondary amino groups means that only two or more primary amino groups, only two or more secondary amino groups, and one each of primary and secondary amino groups. The term “alkoxysilane compound salt” refers to an adduct of an inorganic acid or an organic acid and an alkoxysilane compound that can form an onium salt with an amino group.
[0074]
Examples of such alkoxysilane compounds or salts thereof include those described below, but in the present invention, alkoxysilane compounds or salts thereof having two or more intramolecular primary or secondary amino groups. If it is, it is not limited to these compounds.
[0075]
Embedded image

[0076]
Embedded image

[0077]
Embedded image

[0078]
In these compounds, the alkoxy group that forms alkoxysilyl is preferably an alkoxy group composed of a saturated hydrocarbon, and more preferably a methoxy group, an ethoxy group, or an isopropoxy group because of better storage stability. In addition, for the purpose of reducing sensitivity fluctuation due to storage conditions before heat development, a compound having no unsaturated hydrocarbon group in the molecule is more preferable. In addition, you may use these alkoxysilane compounds or its salt individually by 1 type or in combination of 2 or more types.
[0079]
The image forming layer preferably contains a Schiff base formed by a dehydration condensation reaction between an alkoxysilane compound having at least one primary amino group and a ketone compound.
[0080]
By using such a Schiff base, it is possible to save silver, and an image having low fog, little sensitivity fluctuation, and extremely low gamma can be obtained regardless of the storage conditions before heat development. Furthermore, since the primary amine portion is blocked in advance, when using a ketone-based solvent when preparing an image forming layer forming coating liquid described later, it is possible to suppress fluctuations in sensitivity over time after preparation of the coating liquid. be able to.
[0081]
The ketone compound used for forming the above-mentioned alkoxysilane compound and Schiff base can be used without particular limitation, but has a boiling point of 150 due to the problem of odor generated when an image is formed by the image forming method described later. The thing below 100 degreeC is preferable, and also the thing below 100 degreeC is more preferable.
[0082]
Examples of such a Schiff base include the compounds shown below, provided that the Schiff base is a Schiff base formed from a dehydration condensation reaction between an alkoxysilane compound having one or more primary amino groups and a ketone compound. It is not limited to these.
[0083]
Embedded image

[0084]
Embedded image

[0085]
Of the above-mentioned compounds, a Schiff base having one or more secondary amino groups in the molecule is more preferred for the purpose of further silver saving. These Schiff bases may be used alone or in combination of two or more.
[0086]
As a silver saving agent, when an alkoxysilane compound or a salt thereof, or a Schiff base is added to the image forming layer, it is preferably added in a range of usually 0.00001 to 0.05 mol with respect to 1 mol of silver. . The same category applies when both an alkoxysilane compound or a salt thereof and a Schiff base are added to the image forming layer.
[0087]
However, if the addition amount of the above-mentioned alkoxysilane compound or Schiff base per 1 mol of silver is increased as much as possible, the image density of the unexposed area formed by the image forming method described later may increase. Therefore, for the purpose of alleviating the dependency of the added amount of alkoxysilane compound or Schiff base on 1 mol of silver, an isocyanate compound having two or more isocyanate groups in the molecule may be added to the image forming layer. preferable. As an isocyanate compound, the isocyanate compound used as a crosslinking agent mentioned later can be used.
[0088]
In the present invention, the organic silver salt is a reducible silver source, and is a silver salt of an organic acid or heteroorganic acid, particularly a long-chain (10 to 30 carbon atoms, preferably 15 to 25) aliphatic carboxylic acid and a silver salt. Silver salts of nitrogen heterocyclic compounds are preferred. Preference is also given to organic or inorganic complexes described in RD 17029 and 29963 in which the ligand has a value of 4.0 to 10.0 as the total stability constant for silver ions. Examples of these suitable silver salts include the following.
[0089]
Silver salts of organic acids, for example, silver salts of gallic acid, succinic acid, behenic acid, stearic acid, arachidic acid, palmitic acid, lauric acid and the like. Silver carboxyalkylthiourea salts, for example, silver salts such as 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, aldehydes and hydroxy-substituted aromatic carboxylic acids Silver salts or complexes of polymer reaction products, for example, silver salts of reaction products of aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted acids (eg, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid) Thru complexes, silver salts or complexes of thiones, such as 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-thiazoline-2-thione Silver salt or complex, imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H Complex or salt of nitrogen acid and silver selected from tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benztriazole, silver salt such as saccharin, 5-chlorosalicylaldoxime, and mercaptides Silver salt. Among these, preferable silver salts include silver behenate, silver arachidate, and silver stearate. In the present invention, it is preferable that two or more organic silver salts are mixed in order to improve developability and form a silver image having a high density and a high contrast. For example, a silver ion solution is added to a mixture of two or more organic acids. It is preferable to prepare by mixing.
[0090]
The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver. As described in Japanese Patent Application Laid-Open No. 9-127643, a normal mixing method, a reverse mixing method, and a simultaneous mixing method are used. A controlled double jet method or the like is preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate), and then a controlled double jet. According to the method, the soap and silver nitrate are mixed to produce an organic silver salt crystal. At that time, silver halide grains may be mixed.
[0091]
The organic silver salt according to the present invention can be used in various cases, but tabular grains are preferred. In particular, it is a flat organic silver salt particle having an aspect ratio of 3 or more, and the shape anisotropy of two substantially parallel planes (main planes) having the largest area is reduced to fill the photosensitive layer. In order to carry out, the average value of the acicular ratio of the tabular organic silver salt particles measured from the main plane direction is preferably 1.1 or more and less than 10.0. A more preferable acicular ratio is 1.1 or more and less than 5.0.
[0092]
In the present invention, the term “tabular organic silver salt particles having an aspect ratio of 3 or more” means that the tabular organic silver salt particles occupy 50% or more of the total number of organic silver salt particles. Further, in the organic silver salt according to the present invention, it is preferable that tabular organic silver salt particles having an aspect ratio of 3 or more occupy 60% or more of the total number of organic silver salt particles, and more preferably 70% or more (number). Yes, particularly preferably 80% or more (number).
[0093]
In the present invention, tabular grains having an aspect ratio of 3 or more are grains having a ratio of an average particle diameter to an average thickness, a so-called aspect ratio (abbreviated as AR) represented by the following formula of 3 or more.
[0094]
AR = average particle diameter (μm) / average thickness (μm)
The aspect ratio of the tabular organic silver salt particles according to the present invention is preferably 3 to 20, and more preferably 3 to 10. The reason is that if the aspect ratio is too low, the organic silver salt particles tend to be close-packed, and if the aspect ratio is too high, the organic silver salt particles tend to overlap with each other, and the organic silver salt particles are dispersed in a stuck state. Therefore, light scattering or the like is likely to occur, and as a result, the transparency of the silver salt photothermographic dry imaging material is lowered. Therefore, the above range is considered a preferable range.
[0095]
In order to obtain the average particle size described above, the dispersed organic silver salt is diluted and dispersed on a grid with a carbon support film, and a transmission electron microscope (manufactured by JEOL Ltd., 2000FX type) at a direct magnification of 5000 times. I took a picture. The negative is captured as a digital image with a scanner, and 300 or more particle sizes (equivalent circle diameter) are measured using appropriate image processing software, and the average particle size is calculated.
[0096]
The average thickness described above is calculated by a method using a TEM (transmission electron microscope) as shown below.
[0097]
First, the photosensitive layer coated on the support is attached to an appropriate holder with an adhesive, and an ultrathin slice having a thickness of 0.1 to 0.2 μm is produced using a diamond knife in a direction perpendicular to the support surface. To do. The prepared ultra-thin slice was supported on a copper mesh, transferred onto a carbon film made hydrophilic by glow discharge, and cooled to −130 ° C. or lower with liquid nitrogen using a transmission electron microscope (hereinafter referred to as TEM). A bright field image is observed at a magnification of 5,000 to 40,000, and the image is quickly recorded on a film, an imaging plate, a CCD camera, or the like. At this time, it is preferable to appropriately select a portion where the section is not broken or loosened as the field of view to be observed.
[0098]
As the carbon film, it is preferable to use a very thin collodion, formbar, or the like supported by an organic film. More preferably, the carbon film is formed on a rock salt substrate and dissolved and removed. It is a carbon-only film obtained by solvent and ion etching. The acceleration voltage of TEM is preferably 80 to 400 kV, particularly preferably 80 to 200 kV.
[0099]
In addition, for details of electron microscope observation techniques and sample preparation techniques, see “The Electron Microscopy Society of Kanto Branch / Medical and Biological Electron Microscopy” (Maruzen), “The Electron Microscopy Society of Kanto Branch / Electron Microscope Biological Samples” "Manufacturing method" (Maruzen) can be referred to respectively.
[0100]
A TEM image recorded on a suitable medium is preferably subjected to image processing by a computer after disassembling one image into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more. In order to perform image processing, the analog image recorded on the film is preferably converted into a digital image by a scanner or the like, and shading correction, contrast / edge enhancement, etc. are performed as necessary. Thereafter, a histogram is prepared and a portion corresponding to organic silver is extracted by binarization processing. 300 or more thicknesses of the extracted organic silver salt particles are manually measured with appropriate software, and an average value is obtained.
[0101]
Moreover, the average value of the acicular ratio of the flat organic silver salt particles is obtained by the following method.
First, the photosensitive layer containing tabular organic silver salt particles is swollen with an organic solvent capable of dissolving the photosensitive layer binder, peeled off from the support, and subjected to ultrasonic cleaning, centrifugation, and supernatant removal using the solvent. Repeat 5 times. In addition, the said process is implemented under a safelight.
[0102]
Subsequently, it is diluted with MEK (methyl ethyl ketone) so that the organic silver solid content concentration becomes 0.01%, and after ultrasonic dispersion, it is dropped on a polyethylene terephthalate film hydrophilized by glow discharge and dried.
[0103]
It is preferable that the film on which the particles are mounted is used for observation after the Pt-C having a thickness of 3 nm is obliquely deposited by an electron beam from a 30 ° angle with respect to the film surface by a vacuum deposition apparatus.
[0104]
In addition, for details of electron microscope observation techniques and sample preparation techniques, see “The Electron Microscopy Society of Kanto Branch / Medical and Biological Electron Microscopy” (Maruzen), “The Electron Microscopy Society of Kanto Branch / Electron Microscope Biological Samples” "Manufacturing method" (Maruzen) can be referred to respectively.
[0105]
The prepared sample was observed with a field emission scanning electron microscope (hereinafter referred to as FE-SEM) at an accelerating voltage of 2 to 4 kV and a magnification of 5000 to 20000 times. Save the image.
[0106]
For the above processing, it is convenient to use an apparatus capable of AD-converting the image signal from the electron microscope main body and directly recording it as digital information on the memory, but an analog image recorded on a polaroid film or the like can also be obtained with a scanner or the like. It can be used by converting it to a digital image and applying shading correction, contrast / edge enhancement, etc. as necessary.
[0107]
An image recorded on an appropriate medium is preferably decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels and subjected to image processing by a computer.
[0108]
As the procedure of the image processing described above, first, a histogram is prepared, and a portion corresponding to organic silver salt particles having an aspect ratio of 3 or more is extracted by binarization processing. The aggregated particles are unavoidably cut by an appropriate algorithm or manual operation to extract the contour. Thereafter, the maximum length (MX LNG) and the minimum width (WIDTH) of each particle are measured for at least 1000 particles, and the acicular ratio is determined for each particle by the following formula. The maximum length of a particle means the maximum value when two points in the particle are connected by a straight line. The minimum width of a particle means a value when the distance between the parallel lines becomes a minimum value when two parallel lines circumscribing the particle are drawn.
[0109]
Needle-like ratio = (MX LNG) ÷ (WIDTH)
Then, the average value of the acicular ratio regarding all the measured particles is calculated. When performing the measurement according to the above procedure, it is preferable to sufficiently perform the length correction (scale correction) per pixel and the two-dimensional distortion of the measurement system in advance using a standard sample. Uniform latex particles (DULP) marketed by US Dow Chemical Company are suitable as the standard sample, and polystyrene particles having a coefficient of variation of less than 10% for a particle size of 0.1 to 0.3 μm are used. Specifically, a lot having a particle size of 0.212 μm and a standard deviation of 0.0029 μm is available.
[0110]
The details of the image processing technology can be referred to “Image Processing Application Technology (Industry Research Committee)” edited by Hiroshi Tanaka, and the image processing program or device is not particularly limited as long as the above operation is possible, but as an example Examples include Luzex-III manufactured by Nireco.
[0111]
The method for obtaining the organic silver salt particles having the above-mentioned shape is not particularly limited, but the mixed state at the time of forming the organic acid alkali metal salt soap and / or the mixed state at the time of adding silver nitrate to the soap is excellent. It is effective to maintain and optimize the ratio of silver nitrate that reacts with soap.
[0112]
The tabular organic silver salt particles according to the present invention are preferably preliminarily dispersed together with a binder, a surfactant and the like, if necessary, and then dispersed and ground with a media disperser or a high-pressure homogenizer. For the preliminary dispersion, a general stirrer such as an anchor type or a propeller type, a high speed rotating centrifugal radiation type stirrer (dissolver), or a high speed rotating shear type stirrer (homomixer) can be used.
[0113]
In addition, as the media dispersing machine, a rolling mill such as a ball mill, a planetary ball mill, and a vibrating ball mill, a bead mill that is a medium agitation mill, an attritor, and other basket mills can be used, and a wall as a high-pressure homogenizer. Various types can be used, such as a type that collides with a plug or the like, a type in which liquids are collided at a high speed after dividing the liquid, and a type in which a thin orifice is passed.
[0114]
Examples of ceramics used for ceramic beads used when dispersing media include Al₂O_Three, BaTiO_Three, SrTiO_Three, MgO, ZrO, BeO, Cr₂O_Three, SiO₂, SiO₂-Al₂O_Three, Cr₂O_Three-MgO, MgO-CaO, MgO-C, MgO-Al₂O_Three(Spinel), SiC, TiO₂, K₂O, Na₂O, BaO, PbO, B₂O_Three, SrTiO_Three(Strontium titanate), BeAl₂O_Four, Y_ThreeAl_FiveO₁₂, ZrO₂-Y₂O_Three(Cubic Zirconia), 3BeO-Al₂O_Three-6SiO₂(Synthetic emerald), C (synthetic diamond), Si₂On-nH₂O, titanium silicon, yttrium-stabilized zirconia, zirconia-reinforced alumina and the like are preferable. Yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia are hereinafter abbreviated as zirconia) are particularly preferably used for the reason that less impurities are generated due to friction with beads and dispersers during dispersion.
[0115]
In the apparatus used for dispersing the flat organic silver salt particles according to the present invention, ceramics such as zirconia, alumina, silicon nitride, boron nitride, or diamond is used as the material of the member in contact with the organic silver salt particles. Among them, it is preferable to use zirconia.
[0116]
In carrying out the dispersion, it is preferable to add 0.1 to 10% of the binder concentration of the organic silver, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion through the main dispersion. As preferable operating conditions for this dispersion, for example, when a high-pressure homogenizer is used as the dispersing means, preferable operating conditions are 29.42 MPa to 98.06 MPa, and the number of operations is preferably 2 times or more. Further, when the media disperser is used as the dispersing means, the peripheral speed is preferably 6 m / sec to 13 m / sec.
[0117]
Further, zirconia can be used for a part of the beads and members and can be mixed in the dispersed emulsion at the time of dispersion. This is preferably effective in terms of photographic performance. Zirconia fragments may be added later to the dispersed emulsion or may be added in advance during preliminary dispersion. Although it does not specifically limit as a specific method, If MEK is circulated through the bead mill filled with the zirconia bead as an example, a high concentration zirconia solution can be obtained. What is necessary is just to add this by the preferable density | concentration at a preferable time.
[0118]
In the photosensitive emulsion containing the photosensitive silver halide and the organic silver salt, it is preferable to contain 0.01 mg to 0.5 mg of zirconium per 1 g of silver, and more preferable zirconium content is 0.01 mg to 0.3 mg. Moreover, as a preferable containing form, it is a microparticle with a particle size of 0.02 micrometer or less.
[0119]
In addition, in the silver salt photothermographic dry imaging material according to the present invention, when the cross section perpendicular to the support surface of the material is observed with an electron microscope, it is 0.025 μm.²The proportion of organic silver salt particles exhibiting a projected area of less than 70% of the total projected area of organic silver salt particles, and 0.2 μm²It is formed by coating a photosensitive emulsion containing an organic silver salt having a feature that the ratio of grains exhibiting the above projected area is 10% or less of the total projected area of the organic silver salt grains, and a photosensitive silver halide. . In such a case, the organic silver salt particles are less aggregated in the photosensitive emulsion, and a uniformly distributed state can be obtained.
[0120]
The conditions for producing the photosensitive emulsion having such characteristics are not particularly limited, but the mixed state at the time of forming the organic acid alkali metal salt soap and / or the mixed state at the time of adding silver nitrate to the soap are favorable. Maintaining, optimizing the proportion of silver nitrate that reacts with soap, dispersing and grinding with a media disperser or a high-pressure homogenizer, the binder concentration is 0.1 to 10% of the mass of organic silver In addition to the fact that the temperature from drying to the end of the main dispersion does not exceed 45 ° C., it is preferable to use a dissolver at the time of liquid preparation and stir at a peripheral speed of 2.0 m / second or more.
[0121]
The projected area of the organic silver particles having a specific projected area value as described above, the ratio of the total projected area, and the like are the same as described in the above section for obtaining the average thickness of tabular grains having an aspect ratio of 3 or more. In addition, a portion corresponding to organic silver is extracted by a method using a TEM (transmission electron microscope).
[0122]
At this time, the agglomerated organic silver is treated as a single particle, and the area (AREA) of each particle is obtained. Similarly, the area is determined for at least 1,000, preferably 2,000 particles, and for each, A: 0.025 μm²Less than B: 0.025 μm²0.2 μm or more²Less than C: 0.2 μm²Classify into the above three groups. In the silver salt photothermographic dry imaging material of the present invention, the total area of particles belonging to Group A was 70% or more of the total area of particles, and the total area of particles belonging to Group C was measured. It satisfies 10% or less of the area of all particles.
[0123]
When performing the measurement according to the above procedure, it is preferable to sufficiently perform the length correction (scale correction) per pixel and the two-dimensional distortion of the measurement system in advance using a standard sample. Uniform latex particles (DULP) marketed by US Dow Chemical Company are suitable as the standard sample, and polystyrene particles having a coefficient of variation of less than 10% for a particle size of 0.1 to 0.3 μm are used. Specifically, a lot having a particle size of 0.212 μm and a standard deviation of 0.0029 μm is available.
[0124]
The details of the image processing technology can be referred to “Hiroshi Tanaka Image Processing Application Technology (Industry Study Group)” as described above, and the image processing program or apparatus is not particularly limited as long as the above operation is possible. Also, as an example, Lulex-III manufactured by Nireco Co., Ltd. can be mentioned as described above.
[0125]
The organic silver salt particles according to the present invention are preferably monodisperse particles, preferably having a monodispersity of 1 to 30%. By making monodisperse particles in this range, a high-density image can be obtained. . The monodispersity here is defined by the following formula.
[0126]
Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100
The average particle diameter of the organic silver salt described above is preferably 0.01 to 0.2 μm, more preferably 0.02 to 0.15 μm. The average particle diameter (equivalent circle diameter) is observed with an electron microscope. Represents the diameter of a circle having an area equal to the individual particle image to be produced.
[0127]
In the present invention, in order to prevent devitrification of the silver salt photothermographic dry imaging material, the total amount of silver halide and organic silver salt is 1 m in terms of silver amount.²It is preferably 0.5 g or more and 2.2 g or less. By setting this range, a high-contrast image can be obtained.
[0128]
Binders suitable for the silver salt photothermographic dry imaging materials of the present invention are transparent or translucent and generally colorless and are natural polymer synthetic resins, polymers and copolymers, and other media forming films such as: gelatin, gum arabic, poly (Vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic 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 (esters) Kind Poly (urethanes), phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. It may be hydrophilic or non-hydrophilic.
[0129]
Preferred binders for the photosensitive layer of the silver salt photothermographic dry imaging material according to the present invention are polyvinyl acetals, and a particularly preferred binder is polyvinyl butyral. For non-photosensitive layers such as overcoat layers and undercoat layers, especially protective layers and backcoat layers, cellulose esters which are polymers with higher softening temperatures, especially polymers such as triacetyl cellulose and cellulose acetate butyrate preferable. In addition, as needed, said binder can be used in combination of 2 or more type.
[0130]
Preferred binders according to the present invention are listed as the following compounds.
[0131]
[Table 1]

[0132]
Such a binder is used in an effective range to function as a binder. The effective range can be easily determined by one skilled in the art. For example, as an index for holding at least the organic silver salt in the photosensitive layer, the ratio of the binder to the organic silver salt is preferably in the range of 15: 1 to 1: 2, particularly 8: 1 to 1: 1. That is, the binder amount of the photosensitive layer is 1.5 to 6 g / m.²It is preferable that More preferably 1.7 to 5 g / m²It is. 1.5g / m²If it is less than 1, the density of the unexposed area will be significantly increased, and it may be unusable.
[0133]
In the present invention, it is preferable to contain a matting agent on the photosensitive layer side, and it is preferable to dispose the matting agent on the surface of the silver salt photothermographic dry imaging material in order to prevent damage to the image after heat development. The matting agent is preferably contained in a mass ratio of 0.5 to 10% with respect to the total binder on the photosensitive layer side. The material of the matting agent used in the present invention may be either organic or inorganic. Examples of inorganic substances include silica described in Swiss Patent No. 330,158 and the like, glass powder described in French Patent No. 1,296,995 and the like, and alkali described in British Patent No. 1,173,181 and the like. Earth metals or carbonates such as cadmium and zinc can be used as the matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037 and the like, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, and Japanese Patent Publication No. 44-3643. Polyvinyl alcohol described, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in US Pat. No. 3,079,257, US Pat. No. 3,022,169 etc. An organic matting agent such as prepared polycarbonate can be used. The shape of the matting agent may be either a regular shape or an irregular shape, but is preferably a regular shape, and a spherical shape is particularly preferably used. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere, and the particle size of the matting agent in the present invention indicates the diameter converted into a sphere. The matting agent used in the present invention preferably has an average particle size of 0.5 to 10 μm, more preferably 1.0 to 8.0 μm. The coefficient of variation of the particle size distribution is preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less. The coefficient of variation of the particle size distribution here is
Coefficient of variation = (standard deviation of particle size) / (average value of particle size) × 100 (%)
It is represented by In the present invention, the matting agent can be contained in any constituent layer, but is preferably added to a constituent layer other than the photosensitive layer, more preferably added to the outermost layer as viewed from the support. is there. The method of adding the matting agent may be a method in which the matting agent is dispersed and applied in advance, or a method of spraying the matting agent before the coating solution is applied and drying is completed may be used. . In addition, when a plurality of types of matting agents are added, both the above methods may be used in combination.
[0134]
The silver salt photothermographic dry imaging material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. In order to control the amount of light passing through the photosensitive layer or the wavelength distribution, a filter layer may be formed on the same side or the opposite side of the photosensitive layer, or the dye according to the present invention or a known pigment directly on the photosensitive layer. May be included. The photosensitive layer may be composed of a plurality of layers, and may have a different sensitivity for gradation adjustment, for example, a high sensitive layer / low sensitive layer or a low sensitive layer / high sensitive layer. Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other forming layers. In the silver salt photothermographic dry imaging material of the present invention, for example, surfactants, antioxidants, stabilizers, plasticizers, ultraviolet absorbers, coating aids, and the like may be used.
[0135]
It is preferable to add a toning agent to the silver salt photothermographic dry imaging material of the present invention. Examples of suitable toning agents are disclosed in RD 17029, and specific examples include the following. Imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline, and 2, 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3-mercapto-1,2,4- Triazoles); N- (aminomethyl) aryl dicarboximides (eg N- (dimethylaminomethyl) phthalimide); combinations of blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg N N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate), and 2- (tribromomethylsulfonyl) Benzothiazole combinations); merocyanine dyes (e.g. 3-ethyl-5-((3-ethyl-2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2 , 4-oxazolidinedione); phthalazinone, phthalazinone derivatives or metal salts of these derivatives (eg, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3 -Dihydro-1,4-phthalazinedione); combinations of phthalazinone and sulfinic acid derivatives (examples) 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalic acid combination; phthalazine (including adducts of phthalazine) and maleic anhydride, and At least one selected from phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride) Combinations with compounds; quinazolinediones, benzoxazines, naltoxazine derivatives; benzoxazine-2,4-diones (eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric-triazines ( For example, 2,4-dihydroxypyrimidine), and And tetraazapentalene derivatives (for example, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene) and the like. It is phthalazone or phthalazine.
[0136]
Examples of the silver salt photothermographic dry imaging material of the present invention include, for example, JP-A Nos. 63-159841, 60-140335, 63-231437, 63-259651, 63-304242, 63- 15245, 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.
[0137]
Useful sensitizing dyes used in the present invention are described in or cited in, for example, RD Item 7643IV-A (December 1978, p.23) and Item 1831X (August 1978, p.437). It is described in. In particular, it is preferable to advantageously select a sensitizing dye having spectral sensitivity suitable for spectral characteristics of various scanner light sources.
[0138]
For example, for A) an argon laser light source, simple merocyanines described in JP-A-60-162247, JP-A-2-48653, U.S. Pat. No. 2,161,331, West German Patent 936,071, B ) For helium-neon laser light source, merocyanines shown in trinuclear cyanine dyes described in JP-A-50-62425, 54-18726, 59-102229, C) LED light source And thiacarbocyanines described in JP-B-48-42172, JP-A-51-9609, JP-A-55-39818, JP-A-62-284343, JP-A-2-105135, D) Tricarbocyanines described in JP-A-59-191032 and JP-A-60-80841 for infrared semiconductor laser light sources; Sho 59-192242, formula of JP-A-3-67242 (IIIa), and general formula dicarbocyanine compounds containing 4-quinoline nucleus represented by (IIIb) are advantageously selected. The wavelength of the infrared laser light source is preferably 750 nm or more, more preferably 800 nm or more. In order to cope with a laser in such a wavelength range, JP-A-4-18239, JP-A-5-341432, Japanese Patent Application The sensitizing dyes described in JP-A-6-52387, JP-A-3-10931, US Pat. No. 5,441,866, JP-A-7-13295, and the like are preferably used. These sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is often used particularly for the purpose of supersensitization. In addition to the sensitizing dye, the silver halide emulsion contains a dye that itself does not have spectral sensitizing action or a substance that does not substantially absorb visible light and exhibits supersensitizing action. It is.
[0139]
The silver salt photothermographic dry imaging material of the present invention is formed by preparing a coating liquid in which the above-described constituent layers are dissolved or dispersed in a solvent, and applying a plurality of these coating liquids simultaneously, followed by heat treatment. It is preferable. Here, "multiple simultaneous multi-layer coating" means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and when coating this onto a support, each layer is individually coated and dried repeatedly. In other words, it means that each constituent layer can be formed in such a state that the multilayer coating and drying can be performed simultaneously. That is, the upper layer is provided before the remaining amount of the total solvent in the lower layer reaches 70% by mass or less.
[0140]
There are no particular restrictions on the method of applying multiple layers of each constituent layer simultaneously, and for example, a known method such as a bar coater method, curtain coating method, dipping method, air knife method, hopper coating method, or extrusion coating method may be used. Can do. Of these, a pre-weighing type coating method called an extrusion coating method is more preferable. Since the extrusion coating method does not volatilize on the slide surface unlike the slide coating method, it is suitable for precision coating and organic solvent coating. Although this coating method has been described on the side having the photosensitive layer, the same applies to the case of coating with undercoating when providing the backcoat layer.
[0141]
In the exposure of the photothermographic dry imaging material of the present invention, it is desirable to use a light source suitable for the color sensitivity imparted to the photosensitive material. For example, in the case where the light-sensitive material can be sensed by infrared light, it can be applied to any light source as long as it is in the infrared light range. However, the laser power is high power or silver salt photothermographic dry imaging. An infrared semiconductor laser (780 nm to 820 nm) is more preferably used from the viewpoint that the material can be made transparent.
[0142]
In the present invention, the exposure is preferably performed by laser scanning exposure, but various methods can be adopted as the exposure method. For example, as a first preferable method, there is a method using a laser scanning exposure machine in which an angle formed by an exposure surface of a silver salt photothermographic dry imaging material and a scanning laser beam is not substantially perpendicular.
[0143]
Here, “substantially not perpendicular” means that the angle that is closest to the vertical during laser scanning is preferably 55 ° to 88 °, more preferably 60 ° to 86 °, and even more preferably 65 °. It is at least 84 degrees and most preferably 70 degrees to 82 degrees.
[0144]
The beam spot diameter on the exposed surface of the silver salt photothermographic dry imaging material when the laser beam is scanned onto the silver salt photothermographic dry imaging material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that the smaller the spot diameter, the smaller the angle of deviation of the laser incident angle from the vertical. The lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as generation of interference fringe-like unevenness.
[0145]
As a second method, the exposure in the present invention is preferably performed using a laser scanning exposure machine that emits a scanning laser beam that is a vertical multi. Compared with a longitudinal single mode scanning laser beam, image quality degradation such as occurrence of interference fringe-like unevenness is reduced.
[0146]
In order to make it vertically multi-ply, a method such as using return light by combining or applying high-frequency superposition is preferable. The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.
[0147]
Furthermore, as a third aspect, it is also preferable to form an image by scanning exposure using two or more lasers.
[0148]
As such an image recording method using a plurality of lasers, it is used in an image writing means of a laser printer or a digital copying machine that writes an image for each line in one scan in response to a request for high resolution and high speed. This technique is known, for example, from Japanese Patent Laid-Open No. 60-166916. This is a method in which laser light emitted from a light source unit is deflected and scanned by a polygon mirror and imaged on a photoconductor via an fθ lens or the like. This is a laser scanning optical device that is theoretically the same as a laser imager or the like. It is.
[0149]
The image formation of laser light on the photoconductor in the image writing means of a laser printer or digital copying machine is for one line from the image formation position of one laser light for the purpose of writing an image by a plurality of lines in one scan. The next laser beam is imaged by shifting. Specifically, the two light beams are close to each other in the sub-scanning direction on the image plane with an interval of the order of several tens of μm, and the printing density is 400 dpi (in the present invention, 1 inch per inch, that is, 1 per 2.54 cm). The dot printing density is defined as dpi (dot per inch), and the sub-scanning direction pitch of the two beams is 63.5 μm, and 600 dpi is 42.3 μm. Unlike the conventional method of shifting the resolution in the sub-scanning direction, in the present invention, it is preferable to form an image by condensing two or more lasers at the same location on the exposure surface while changing the incident angle. In this case, when the exposure energy on the exposure surface when writing is performed with one ordinary laser (wavelength λ [nm]) is E, N lasers used for exposure have the same wavelength (wavelength λ [nm]. ]), The same exposure energy (En) is preferably in the range of 0.9 × E ≦ En × N ≦ 1.1 × E. By doing so, energy is secured on the exposure surface, but the reflection of each laser beam to the image forming layer is reduced because the exposure energy of the laser is low, and thus the occurrence of interference fringes is suppressed.
[0150]
In the above description, a plurality of lasers having the same wavelength as λ are used. However, lasers having different wavelengths may be used. In this case, it is preferable that (λ−30) <λ1, λ2,... Λn ≦ (λ + 30) is satisfied with respect to λ [nm].
[0151]
In the image recording methods according to the first, second, and third aspects described above, solid-state lasers such as ruby lasers, YAG lasers, glass lasers, and the like that are generally well known as lasers used for scanning exposure; He— Ne laser, Ar ion laser, Kr ion laser, CO₂Laser, CO laser, He-Cd laser, N₂Gas laser such as laser and excimer laser; InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP₂Lasers, semiconductor lasers such as GaSb lasers; chemical lasers, dye lasers, etc. can be selected and used in a timely manner, but among these, semiconductor lasers with a wavelength of 600-1200 nm are used due to maintenance and light source size problems. It is preferable to use it. In the laser used in a laser imager or a laser image setter, the beam spot diameter on the material exposure surface when scanned with a silver salt photothermographic dry imaging material is generally 5 to 75 μm as a minor axis diameter, The major axis diameter is in the range of 5 to 100 μm, and the laser beam scanning speed is set to the optimum value for each silver salt photothermographic dry imaging material depending on the sensitivity and laser power at the laser oscillation wavelength inherent to the silver salt photothermographic dry imaging material. can do.
[0152]
In the present invention, the development conditions vary depending on the equipment, equipment, or means used, but typically the heating of the imagewise exposed photothermographic dry imaging material at a suitable high temperature. Accompany. The latent image obtained after the exposure is obtained at a moderately high temperature (for example, about 80 to 200 ° C., preferably about 100 to 200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). The dry imaging material can be developed by heating.
[0153]
When the heating temperature is 80 ° C. or lower, sufficient image density cannot be obtained in a short time. When the heating temperature is 200 ° C. or higher, the binder is melted, and not only the image itself, such as transfer to a roller, but also adversely affects the transportability and the developing machine. Effect. By heating, a silver image is generated by an oxidation-reduction reaction between an organic silver salt (which functions as an oxidizing agent) and a reducing agent. This reaction process proceeds without any supply of treatment liquid such as water from the outside.
[0154]
The apparatus, device, or means for heating may be performed by a heating means typical as a heat generator using a hot plate, an iron, a hot roller, carbon, white titanium, or the like. More preferably, in the silver salt photothermographic dry imaging material provided with the protective layer according to the present invention, the surface on the side having the protective layer is brought into contact with the heating means for the heat treatment. It is preferable from the viewpoints of thermal efficiency, workability, and the like, and it is preferable that the surface is conveyed while being in contact with a heat roller, heated and developed.
[0155]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.
[0156]
  referenceExample 1
  《Preparation of silver salt photothermographic dry imaging material sample》
  A silver salt photothermographic dry imaging material was prepared according to the method described below.
[0157]
(Production of support)
8 W / m on both sides of a polyethylene terephthalate film with a thickness of 175 μm, which is colored blue with a concentration of 0.160 (measured with a Konica Densitometer PDA-65).²・ Corona discharge treatment for a minute was performed.
[0158]
(Preparation of photosensitive emulsion)
[Preparation of photosensitive silver halide emulsion 1]
A1
Phenylcarbamoyl gelatin 88.3g
Compound (A) (10% methanol solution) 10 ml
Potassium bromide 0.32g
Finish to 5429 ml with water
B1
0.67M / L Silver nitrate aqueous solution 2635ml
C1
Potassium bromide 51.55g
Potassium iodide 1.47g
Finish to 660ml with water
D1
Potassium bromide 154.9g
4.41 g of potassium iodide
E1
0.4M / L potassium bromide aqueous solution The following silver potential control amount
F1
56% acetic acid aqueous solution 16.0 ml
G1
Anhydrous sodium carbonate 1.72 g
Finish to 151ml with water
Compound (A):
HO (CH₂CH₂O)_n-[CH (CH_Three) CH₂O]₁₇-(CH₂CH₂O)_mH
m + n = 5-7
Using the mixing stirrer shown in Japanese Patent Publication Nos. 58-58288 and 58-58289, 1/4 of the solution (B1) and the total amount of the solution (C1) are controlled at 45 ° C. and pAg 8.09 in the solution (A1). However, nucleation was performed by adding 4 minutes 45 seconds by the simultaneous mixing method.
[0159]
After the elapse of 7 minutes, the remainder of the solution (B1) and the total amount of the solution (D1) were added over 14 minutes and 15 seconds by a simultaneous mixing method while controlling the temperature at 45 ° C. and pAg 8.09. During mixing, the pH of the reaction solution was 5.6.
[0160]
After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of the solution (F1) was added, and the silver halide emulsion was precipitated. The supernatant was removed leaving 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide was precipitated again. The remaining portion of 1500 ml was left, the supernatant was removed, 10 L of water was further added, and after stirring, the silver halide was precipitated. After leaving 1500 ml of the sedimented portion and removing the supernatant, the solution (G1) was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added to 1161 g per mole of silver.
[0161]
The resulting photosensitive silver halide emulsion 1 was cubic silver iodobromide grains having an average grain size of 0.061 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%.
[0162]
Next, pH of the photosensitive silver halide emulsion 1 was adjusted to 7 at 60 ° C. Sodium thiosulfate 1 × 10^-FourMol / Ag mol and triphenylphosphine selenide 0.2 × 10^-FourMol / Ag mol solid particulate dispersion was added and ammonium thiocyanate 5.8 × 10^-3Mol / Ag mol, chloroauric acid 0.4 × 10^-FourMole / Ag mol was added. Stir for 120 minutes. The fog inhibitor of general formula (A) was added as shown in Table 2. After ripening, the mixture is cooled to 38 ° C. to complete chemical sensitization, which is designated as photosensitive silver halide emulsions Em-1a to Em-1g.
[0163]
[Preparation of photosensitive silver halide emulsion Em-2a, 2b]
The photosensitive silver halide emulsion 1 is chemically sensitized with the pH of 5.8 to obtain photosensitive silver halide emulsion Em-2a. Further, the fog inhibitor of the general formula (A) is added as shown in Table 2 to obtain Em-2b.
[0164]
[Preparation of Powdered Organic Silver Salt-1a-1g]
In 4720 ml of pure water, 104.6 g of behenic acid, 54.2 g of arachidic acid, 34.9 g of stearic acid, and 1.8 g of palmitic acid were dissolved at 80 ° C. Next, 540.2 ml of a 1.5 M / L sodium hydroxide aqueous solution was added while stirring at high speed, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain an organic acid sodium solution. While maintaining the temperature of the organic acid sodium solution at 55 ° C., 0.038 mol of the above light-sensitive silver halide emulsion Em-1a and 450 ml of pure water were added as silver, and the mixture was stirred at high speed for 5 minutes. Next, 760.6 ml of 1 M / L silver nitrate solution was added over 2 minutes, and the mixture was further stirred for 10 minutes at high speed, and then water-soluble salts were removed by filtration. Thereafter, washing with deionized water and filtration were repeated until the conductivity of the filtrate reached 2 μS / cm, and centrifugal dehydration was performed, followed by drying under a heated nitrogen stream until there was no decrease in mass. Powdered organic silver salt-1a was obtained. Further, from the photosensitive silver halide emulsions Em-1b to Em-1g, powdered organic silver salts-1b to 1g were obtained in the same manner.
[0165]
[Preparation of powdered organic silver salt-2a, 2b]
Using light-sensitive silver halide emulsions Em-2a and 2b, powdered organic silver salts -2a and 2b were obtained in the same manner as described above.
[0166]
[Preparation of photosensitive emulsion dispersion-1a to 1g]
14.57 g of polyvinyl butyral powder (Monsanto Butvar B-79) was dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK), and 500 g of powdered organic silver salt-1a was gradually added while stirring with a dissolver type homogenizer. And mixed well. Thereafter, dispersion was performed at a peripheral speed of 13 m and a residence time in the mill of 0.5 minutes using a media type disperser (manufactured by gettzmann) filled with 80% of 1 mm diameter Zr beads (manufactured by Toray). Thus, photosensitive emulsion dispersion-1a was prepared. Further, photosensitive emulsion dispersions-1b to 1g were obtained from powdered organic silver salts 1b to 1g in the same manner.
[0167]
[Preparation of photosensitive emulsion dispersions-2a and 2b]
14.57 g of polyvinyl butyral powder (Monsanto Butvar B-79) is dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK), and 500 g of powdered organic silver salt-2a or 2b is gradually added while stirring with a dissolver type homogenizer. And mixed well. Thereafter, the dispersion was carried out at a peripheral speed of 13 m and a residence time in the mill of 0.5 minutes using a media type disperser (manufactured by gettzmann) filled with 80% of 1 mm diameter Zr beads (manufactured by Toray). 2a and 2b were prepared.
[0168]
(Preparation of coating solution)
Preparation of stabilizer solution
A stabilizer solution was prepared by dissolving 1.0 g of Stabilizer-1 and 0.31 g of potassium acetate in 4.97 g of methanol.
[0169]
Preparation of infrared sensitizing dye solution
19.2 mg of infrared sensitizing dye Dye-1, 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer-2 were dissolved in 31.3 ml of MEK to prepare an infrared sensitizing dye solution. .
[0170]
Preparation of additive liquid a
0.25 mol / Ag mol of reducing agent, 1.54 g of 4-methylphthalic acid, and 0.48 g of infrared dye were dissolved in 110 g of MEK to obtain an additive solution a.
[0171]
Preparation of additive liquid b
3.56 g of antifoggant and 3.43 g of phthalazine were dissolved in 40.9 g of MEK to obtain additive liquid b.
[0172]
[Preparation of photosensitive layer coating solutions 1a-1g, 2a, 2b]
The photosensitive emulsion dispersions 1a to 1g, 2a and 2b were each kept at 17 ° C. while stirring (50 g) and 15.11 g of MEK, respectively, and the fog inhibitor bis (dimethylacetamide) dibromobromate (10% methanol solution) 0 .32 g was added and stirred for 1 hour. Subsequently, 0.34 g of a stabilizer solution was added and stirred for 10 minutes, and then 2.0 g of an infrared sensitizing dye solution was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 25 minutes. 2 g of 0.2% methanol solution of Stabilizer-3 was added. After 5 minutes, 13.31 g of polyvinyl acetal resin P-1 as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. . While continuing stirring, 1.6 ml of Desmodur N3300 / Mobay aliphatic isocyanate (10% MEK solution), 12.43 g of additive a, and 4.27 g of additive b were sequentially added and stirred for photosensitivity. Layer coating solutions 1a to 1g, 2a and 2b were obtained.
[0173]
Embedded image

[0174]
Embedded image

[0175]
While stirring 865 g of MEK, 96 g of cellulose acetate butyrate (manufactured by Eastman Chemical, CAB171-15), 4.5 g of polymethylmethacrylic acid (Rohm & Haas, Paraloid A-21), vinyl sulfone compound HD- 1.5 g of 1 (* 1), 1.0 g of benzotriazole, and 1.0 g of F-based activator (Asahi Glass Co., Surflon KH40) were added and dissolved. Next, 30 g of the following matting agent dispersion was added, and 15 g of phthalazine was added while stirring to prepare a surface protective layer coating solution.
[0176]
(* 1) HD-1: 1,3- {bis (vinylsulfonyl)}-2-hydroxypropane
<Preparation of matting agent dispersion>
Dissolve 7.5 g of cellulose acetate butyrate (Eastman Chemical, CAB171-15) in 42.5 g of MEK, and add 5 g of calcium carbonate (Special Minerals, Super-Pflex200) to the dissolver type homogenizer. Then, a matting agent dispersion was prepared by dispersing at 8000 rpm for 30 minutes.
[0177]
[Preparation of back surface coating solution]
While stirring MEK830 g, 84.2 g of cellulose acetate butyrate (manufactured by Eastman Chemical, CAB381-20) and 4.5 g of polyester resin (manufactured by Boston, VitelPE2200B) were added and dissolved. An infrared dye is added to the dissolved solution so that the absorbance of the absorption maximum of the infrared dye in the coating sample on the back surface is 0.35, and further a fluorine-based activator dissolved in 43.2 g of methanol (Asahi Glass Co., Ltd.) Manufactured by Surflon KH40) and 2.3 g of a fluorine-based activator (Dainippon Ink Co., Ltd., MegaFag F120K) were added and sufficiently stirred until dissolved. Lastly, 75 g of silica (manufactured by WR Grace, Syloid 64X6000) dispersed in MEK at a concentration of 1% by mass with a dissolver type homogenizer was added and stirred to prepare a coating solution for the back surface.
[0178]
<Production of support>
0.5 kV · A · min / m on one surface of polyethylene terephthalate film base (thickness: 175 μm) colored blue with a concentration of 0.170²After applying the corona discharge treatment, an undercoat layer a was coated thereon using the following undercoat coating solution A so that the dry film thickness was 0.2 μm. Furthermore, 0.5 kV · A · min / m is similarly applied to the other surface.²After applying the corona discharge treatment, the undercoat coating solution B below was used to coat the undercoat layer b so that the dry film thickness was 0.1 μm. Then, heat processing was performed for 15 minutes at 130 degreeC in the heat processing type oven which has a film conveyance apparatus which consists of a some roll group.
[0179]
(Undercoating liquid A)
270 g of copolymer latex liquid (solid content 30%) of 30% by mass of n-butyl acrylate, 20% by mass of t-butyl acrylate, 25% by mass of styrene and 25% by mass of 2-hydroxyethyl acrylate, surfactant (UL-1 ) 0.6 g and methyl cellulose 0.5 g were mixed. Further, 1.3 g of silica particles (Syloid 350, manufactured by Fuji Silysia) was added to 100 g of water, and dispersed for 30 minutes with an ultrasonic disperser (manufactured by ALEX Corporation, Ultrasonic Generator, frequency 25 kHz, 600 W). The dispersion liquid was added, and finally it was made up to 1000 ml with water to obtain an undercoat coating liquid A.
[0180]
Embedded image

[0181]
(Preparation of colloidal tin oxide dispersion)
A homogeneous solution was prepared by dissolving 65 g of stannic chloride hydrate in 2000 ml of a water / ethanol mixed solution. Subsequently, this was boiled and the coprecipitate was obtained. The generated precipitate was taken out by decantation and washed several times with distilled water. Silver nitrate is dropped into distilled water from which the precipitate has been washed, and after confirming that there is no reaction of chlorine ions, distilled water is added to the washed precipitate to make a total volume of 2000 ml. Furthermore, 40 ml of 30% aqueous ammonia was added, the aqueous solution was heated, and concentrated to a volume of 470 ml to prepare a colloidal tin oxide dispersion.
[0182]
(Undercoating liquid B)
A copolymer latex liquid (solid content 30) of 37.5 g of the colloidal tin oxide dispersion, 20% by mass of n-butyl acrylate, 30% by mass of t-butyl acrylate, 27% by mass of styrene and 28% by mass of 2-hydroxyethyl acrylate. %) 3.7 g, n-butyl acrylate 40 mass%, styrene 20 mass%, glycidyl methacrylate 40 mass% copolymer latex liquid (solid content 30%) 14.8 g and surfactant UL-1 0.1 g Were mixed and finished to 1000 ml with water to obtain an undercoat coating solution B.
[0183]
(Coating on the photosensitive layer side and back side)
[Coating on the photosensitive layer side]
Using the prepared photosensitive layer coating solutions 2a, 2b, 1a to 1g and the surface protective layer coating solution, the photosensitive layer and the surface protective layer were respectively coated from the support side by using an extrusion coater to simultaneously apply silver. Salt photothermographic dry imaging material sample no. 1-9 were produced. The photosensitive layer is a single layer coating, and the silver coating amount is 1.8 g / m.²Further, drying was performed for 5 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C. The surface protective layer was formed to have a dry film thickness of 1.45 μm.
[0184]
[Application on the back side]
The prepared back surface coating solution was applied and dried using an extrusion coater so that the dry film thickness was 3 μm. The drying temperature was 100 ° C., and drying was performed for 5 minutes using a drying air having a dew point temperature of 10 ° C.
[0185]
<Evaluation of silver salt photothermographic dry imaging materials>
Silver salt photothermographic dry imaging material sample No. About 1-9, the characteristic evaluation was performed with the following method.
[0186]
(Measurement of fog and sensitivity)
Each of the silver salt photothermographic dry imaging materials prepared above was processed into a half-cut size, and then each sample was subjected to imagewise exposure with a 810 nm semiconductor laser. In the exposure, the angle between the exposure surface of the sample and the exposure laser beam was 80 degrees, the laser output was 75 mW, and high frequency superposition was output in the vertical multimode. Exposure time is 1 × 10^-7Exposed in seconds. The heat development processing was performed uniformly using a heat drum, and the processing conditions were 123 ° C. and 13.5 seconds. The density of the heat-developed sample prepared as described above was measured with an optical densitometer (PD-82 manufactured by Konica), and a characteristic curve consisting of the density D and the exposure amount Log (1 / E) was prepared. Concentration (fog density) and sensitivity were measured. The sensitivity was defined as the logarithm of the reciprocal of the exposure amount giving a density 1.0 higher than the minimum density (fogging density). The photographic characteristic value gamma represents the slope (gradation γ) of the characteristic curve. Here, gamma indicates a gradient from (minimum density + 0.25) to (minimum density + 2.5). Note that the results other than the gradation γ indicate the sample No. The relative value with 1 being the reference 100 is shown.
[0187]
(Evaluation of storage stability)
The produced silver salt photothermographic dry imaging materials (Sample Nos. 1 to 9) were each enclosed in a light-shielding sealed container whose interior was maintained at 25 ° C. and a relative humidity of 60%, and aged for 7 days at 55 ° C. . This is called forced aging treatment. Each sample subjected to the treatment was subjected to the same exposure and heat development as those used for the evaluation of fog and sensitivity and measured. The results are shown in Sample No. It is shown as a relative value with a sample of 1 on the same day as reference 100.
[0188]
[Table 2]

[0189]
[Table 3]

[0191]
  referenceExample 2
  [Preparation of photosensitive silver halide emulsion 3]
  referenceThe light-sensitive silver halide emulsion 3 was prepared in the same manner as the light-sensitive silver halide emulsion 1 except that the temperature after nucleation was changed from 45 ° C. to 30 ° C. in the preparation process of the light-sensitive silver halide emulsion of Example 1. Prepared. This emulsion was cubic silver iodobromide grains having an average grain size of 0.040 μm and a variation coefficient of 11% and a [100] face ratio of 91%.
[0192]
  Photosensitive silver halide emulsion 3 abovereferencePrepared in the same manner as the light-sensitive silver halide emulsion 1 described in Example 1, except that chemical sensitization was carried out with Hypo instead of sulfur, selenium, and gold sensitizers, and general formula (1-1) or (1-2). And the compound of general formula (A) was carried out as shown in Table 4. This is designated as photosensitive silver halide emulsions Em-3a to 3i.
[0193]
  Subsequently, these photosensitive silver halide emulsions Em-3a-3ireferenceA photosensitive layer coating solution was obtained from the photosensitive emulsion dispersion by the method of Example 1. Also,referenceA coated sample was prepared in the same manner as in Example 1.
[0194]
  Evaluation methodreferenceObtained in the same manner as in Example 1. The fogging and sensitivity are the same as in sample No. 10 relative day samples are shown as relative values.
[0195]
[Table 4]

[0196]
[Table 5]

[0198]
  Example1
  [Preparation of photosensitive silver halide emulsion 4]
  referenceThe photosensitive silver halide emulsion 3 of Example 2 that is not chemically sensitized is designated as photosensitive silver halide emulsion 4.referenceA photosensitive emulsion dispersion 4 was obtained by the method of Example 1.
[0199]
  (Preparation of coating solution)
  Stabilizer solution, infrared sensitizing dye solution, additive solution a and additive solution breferenceThe same one as prepared in Example 1 was used.
[0200]
[Preparation of Additive C]
As shown in Table 6, the compound of the general formula (P1), 3.43 g of phthalazine was dissolved in 40.9 g of MEK to obtain an additive solution C.
[0201]
[Preparation of upper photosensitive layer coating solutions Em-4a to 4l]
The photosensitive emulsion dispersion 4 (50 g) and 15.11 g of MEK were kept at 13 ° C. with stirring to pH 7 and the compounds of the general formulas (1-1) and (1-2) were added as shown in Table 6. And stirred for 30 minutes. Thereafter, 0.32 g of the fog inhibitor bis (dimethylacetamide) dibromobromate (10% methanol solution) was added and stirred for 1 hour. Subsequently, 10% by weight of CaBr₂4 ml of methanol solution was added and stirred for 20 minutes. Further, 0.34 g of a stabilizer solution was added and stirred for 10 minutes, and then 2.0 g of an infrared sensitizing dye solution was added and stirred for 1.5 hours. Thereafter, 2 g of a 0.2% methanol solution of Stabilizer-3 was added. After 5 minutes, 13.31 g of polyvinyl acetal resin P-1 as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. . While further stirring, 1.6 ml of Desmodur N3300 / Mobay aliphatic isocyanate (10% MEK solution), 12.43 g of additive a, and the compound of general formula (A) were added as shown in Table 6, and then 4.27 g of additive solution C was sequentially added and stirred to obtain photosensitive layer coating solutions Em-4a to Em-4l.
[0202]
[Preparation of lower photosensitive layer coating solutions Em-5a to 5c]
The photosensitive emulsion dispersion 4 (50 g) and 15.11 g of MEK were kept at 13 ° C. while stirring, 0.32 g of bis (dimethylacetamide) dibromobromate (10% methanol solution) was added, and the mixture was stirred for 1 hour. Subsequently, 0.34 g of a stabilizer solution was added and stirred for 10 minutes, and then 2.0 g of an infrared sensitizing dye solution was added and stirred for 1.5 hours. Thereafter, 2 g of a 0.2% methanol solution of Stabilizer-3 was added. After 5 minutes, 13.31 g of polyvinyl acetal resin P-1 as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. . While further stirring, 12.43 g of additive liquid a, 1.6 ml of Desmodur N3300 / Movey aliphatic isocyanate (10% MEK solution), 4.27 g of additive liquid b, as shown in Table 6 were saved. Silvering agents (10% MEK solution) were sequentially added and stirred to obtain photosensitive layer coating solutions Em-5a to Em-5c.
[0203]
[Coating on the photosensitive layer side]
By using each prepared photosensitive layer coating solution and each surface protective layer coating solution, a silver salt layer was formed by simultaneously applying multiple layers of the photosensitive layer lower layer, photosensitive layer upper layer and surface protective layer from the support side using an extrusion coater. Photothermographic dry imaging material sample No. 19-30 were produced. The amount of silver applied is 1 g / m²Sample No. 19-No. The photosensitive layer 30 is a two-layer coating, and the lower layer (undercoat layer, support side) is 0.33 g / m as the coating silver amount.²The upper layer (surface protective layer side) of the photosensitive layer is 0.67 g / m as the applied silver amount.²Further, drying was performed for 5 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C. The surface protective layer was dried to a thickness of 1.45 μm.
[0204]
  Evaluation methodreferenceObtained in the same manner as in Example 1. The fogging and sensitivity are the same as in sample No. 19 relative samples with the same 100 as the same day sample.
[0205]
(Evaluation of image preservation)
Two samples treated in the same way as the sensitometric evaluation were stored for 5 days at 25 ° C and 55%, and protected for 7 days. The other sample was stored at 40 ° C and 55% for 7 days. After being exposed on the light source stand, the density of the fog portion of both was measured. The results are shown in Table 7.
[0206]
Increase in fog = fogging after exposure to light-fogging when stored under shading was evaluated for image storability. The results are shown in Sample No. 19 is shown as a relative value with reference 100.
[0207]
(Silver tone evaluation)
It was exposed and developed by the method described above. A sample that was exposed and developed so that the density of the sample after development was 1.1 ± 0.05 was prepared. Hue angle h defined by JIS Z 8729 at optical density D = 1.1 ± 0.05_abIt is calculated by.
[0208]
Evaluation standard is h_abRange of
A: 200 ° <h_ab<250 °
○: 195 ° <h_ab<199 °, 251 ° <h_ab<255 °
Δ: 190 ° <h_ab<194 °, 256 ° <h_ab<260 °
X: h_ab<189 °, 261 ° <h_ab
[0209]
[Table 6]

[0210]
[Table 7]

[0211]
As is clear from Table 7, the sample having the configuration of the present invention has a low fog density, sufficient sensitivity, and excellent silver tone as compared with the comparative product. Moreover, it is a medical photosensitive material with good gradation. It can also be seen that the silver salt photothermographic dry imaging material has good storage stability before development and image storage after development.
[0212]
【The invention's effect】
According to the present invention, a silver salt photothermographic dry imaging material for a laser imager and an image setter output film having high sensitivity, low fog, excellent image storage stability and good storage stability, and an image forming method thereof are provided. I was able to.

Claims (7)

Silver salt photothermographic dry imaging having a layer containing a photosensitive emulsion containing at least a non-photosensitive aliphatic carboxylic acid silver salt and a photosensitive silver halide, a silver ion reducing agent, a binder, and a crosslinking agent on a support Silver salt photothermographic dry imaging characterized in that at least one of the silver halides is chemically sensitized in the presence of a compound represented by the following general formula (P1) at a pH of 6 to 10 in the material material.

[Wherein, X ₅ , X ₆ , X ₇ and X ₈ each represent a halogen atom, and B ₁ and B ₂ each independently represent a hydrogen atom, a halogen atom or a substituent. p represents an integer of 1 to 3, and J represents an alkylene group, a cycloalkylene group, an alkenylene group, an alkynylene group, or a p + 1 valent group derived from each group. G ₁ and G ₂ represent a linking group. However, when G ₁ and G ₂ are both —SO ₂ —, p represents 2 or 3. ] An alkoxysilane compound or a salt thereof having two or more photosensitive emulsion layers containing a photosensitive emulsion and having two or more primary or secondary amino groups in the silver halide emulsion of the photosensitive emulsion layer adjacent to the support the silver salt photothermographic dry imaging material of claim 1, wherein the containing. The image is developed at a development temperature of 123 ° C. and a development time of 13.5 seconds. When shown as a characteristic curve on Cartesian coordinates, the optical tone has an average gradation of 0.25 to 2.5 of 2.5 to 5.0 and a maximum density of 3.0 to 4.5. The silver salt photothermographic dry imaging material according to claim 1 or 2 . An image forming method comprising exposing the silver salt photothermographic dry imaging material according to any one of claims 1 to 3 with a 600 to 900 nm red to infrared laser to form an image. 5. The image forming method according to claim 4, wherein the exposure is performed by a laser scanning exposure machine in which an angle formed between the exposure surface and the scanning laser beam is not substantially perpendicular. 5. The image forming method according to claim 4, wherein the scanning laser beam is exposed by a laser scanning exposure machine having a vertical multi. An image forming method, wherein the silver salt photothermographic dry imaging material according to any one of claims 1 to 3 is heated and developed at a temperature of 80 ° C to 200 ° C after exposure.