JP3691571B2 - Photothermographic material - Google Patents

Description

【００３９】
【化２】

【００４０】
【化３】

【００４１】
式中Ｒ₁ およびＲ₂ の各々はアルキル基、置換アルキル基、アリール基、置換アリール基、アリル基、アラルキル基、置換アラルキル基、またはシクロアルキル基を表しＺ₁ およびＺ₂ の各々は５または６員の複素環を完結させるのに必要な原子を表し、Ｘ^- は陰イオンを表すが、Ｒ₁ および／またはR₂自体が陰イオンを含有するときはＸ^- は存在しないものとする。Ｍ⁺ は陽イオンを表す。R₃、Ｒ₄ はアルキル基、置換アルキル基、アリール基、置換アリール基、シクロアルキル基もしくはを表し、R₃とR₄が連結された構造でシクロアルキレン骨格を表す。
【００４２】
本発明における色素の構造をさらに詳述すると、Ｒ₁ およびＲ₂ （同種または異種）はいずれもシアニン色素のシアニン窒素原子に含まれるタイプの公知の置換基群の中から選択できるが、特に特公昭５１−４１０６１号公報に記載されているのと全く同じ同一の範囲に属する置換基群から選択できる。
【００４３】
この中で特に有効に用いられるＲ₁ およびＲ₂ の置換基は、メチル、エチル、プロピル、イソプロピル、ブチル、イソブチルなどのアルキル基や、カルボキシメチル、カルボキシエチル、カルボキシプロピル、カルボキシブチルなどのカルボキシアルキル基や、スルホエチル、スルホプロピル、スルホブチルなどのスルホアルキル基や、スルフェートプロピル、スルフェートブチルなどのスルフェートアルキル基や、ヒドロキシアルキル基や、さらにはＮ−（メチルスルホニル）−カルバミル−メチル基、γ−（アセチル−スルファミル）−ブチル基などのＮ置換アルキル基、アリル基、ベンジル基などのアラルキル基、カルボキシベンジル、スルホベンジルなどの置換アラルキル基、フェニル基などのアリール基、カルボキシフェニル、スルフォフェニルなどの置換アリール基、シクロヘキシルなどのシクロアルキル基を例としてあげることができる。
【００４４】
Ｚ₁ およびＺ₂ （同種または異種）はいずれも５または６員の複素環を完結するのに必要な原子群を表し、特に特公昭５１−４１０６１号公報記載の複素環系列の中から任意に選択できる。
【００４５】
その代表骨格としては、例えばチアゾール、４−メチルチアゾール、４−フェニルチアゾール、４，５−ジメチルチアゾールなどのチアゾール系列の核や、ベンゾチアゾール、５−クロロベンゾチアゾール、５，６−ジメチルベンゾチアゾール、５，６−ジメトキシベンゾチアゾールなどのベンゾチアゾール系列の核や、ナフト〔２，１−ｄ〕チアゾール、ナフト〔１，２−ｄ〕チアゾール、５−メトキシナフト〔１，２−ｄ〕チアゾールなどのナフトチアゾール系列の核や、７−メトキシチオナフテノ〔７，６−ｄ〕チアゾールなどのチオナフテン〔７，６−ｄ〕チアゾール系列の核や、４−メチルオキサゾール、５ーメチルオキサゾール、４−フェニルオキサゾール、４，５−ジメチルオキサゾールなどのオキサゾール系列の核や、ベンズオキサゾール、５−クロロベンズオキサゾール、５−メチルベンズオキサゾール、５，６−ジメチルベンズオキサゾール、５−メトキシベンズオキサゾール、５−ヒドロキシベンズオキサゾールなどのベンズオキサゾール系列の核や、ナフト〔１，２−ｄ〕オキサゾールなどのナフトオキサゾール系列の核や、４−メチルセレナゾールなどのセレナゾール系列の核、ベンゾセレナゾール、５−メチルベンゾセレナゾール、５−メトキシベンゾセレナゾールなどのベンゾセレナゾール系列の核、ナフト〔２，１−ｄ〕セレナゾールなどのナフトセレナゾール系列の核、チアゾリン、４−メチルチアゾリン４，４−ビスヒドロキシメチルチアゾリンなどのチアゾリン系列の核、オキサゾリン系列の核、セレナゾリン系列の核や、キノリン、６−メチルキノリン、６−エトキシキノリン、６−ナフトキシキノリンなどの４−キノリン系列の核、１−イソキノリン系列の核、３−イソキノリン系列の核や、３，３−ジメチルインドレニン、３，３−ジメチル−５−クロロ−インドレニン、３，３，５−トリメチルイソインドレニンなどの３，３−ジアルキルインドレニン系列の核や、ピリジン、５−メチルピリジンなどのピリジン系列の核や、１−エチル−５，６−ジクロロベンズイミダゾール、１−ヒドロキシエチル−５，６−ジクロロベンズイミダゾール、１−エチル−５−クロロベンズイミダゾール、１−エチル−５−フルオロ−６−シアノベンズイミダゾール、１−エチル−５−エチルスルフォニルベンズイミダゾール、１−エチル−５−メチルスルフォニルベンズイミダゾール、１−エチル−５−トリフルオロメチルスルフォニル−ベンズイミダゾール、１−エチル−５−トリフルオロメチルスフィニルベンズイミダゾールなどのベンズイミダゾール系列の核を完成する骨格群をあげることができる。
【００４６】
Ｘ^- は塩素イオン、臭素イオン、沃素イオン、過塩素酸イオン、ベンゼンスルホン酸イオン、ｐ−トルエンスルホン酸イオン、メチル硫酸イオン、エチル硫酸イオン、プロピル硫酸イオンなどの陰イオンを表すが、Ｒ₁ および／またはＲ₂ 自体が陰イオン基、例えば−ＳＯ₃ ^- 、−ＯＳＯ₃ ^- 、−ＣＯＯ^- 、−ＳＯ₂ Ｎ^- −、−ＳＯ₂ −Ｎ^- −ＣＯ−、−ＳＯ₂ −Ｎ^- −ＳＯ₂ −などを含むときにはＸ^- は存在しない。
【００４７】
Ｍ⁺ は例えば水素陽イオン、金属陽イオン、または無機もしくは有機のオニウム陽イオン（アンモニウム、ピリジニウムなど）のような陽イオンを表す。
【００４８】
本発明においてＲ₃ およびＲ₄ （同種または異種）は、原則的にはＲ₁ およびＲ₂ と同一の範囲に属する置換基群から選択することができる。また、Ｒ₃ およびＲ₄ は互いに連結して例えばシクロへキシレン骨格やシクロぺンチレン骨格などのシクロアルキレン骨格を形成しても良い。このシクロアルキレン骨格の一部は炭素原子以外の酸素、窒素などの原子に置換されても良く、例えばモルホリン骨格やピペラジン骨格を形成しても良い。
上記一般式で表される色素の構造の例を以下に示す。
【００４９】
【化４】

【００５０】
【化５】

【００５１】
【化６】

【００５２】
本発明においては感光性ハロゲン化銀と有機銀塩とを混合する前に感光性ハロゲン化銀粒子に増感色素を吸着させることが好ましい。
感光性ハロゲン化銀粒子に増感色素を添加するタイミングとしてはいずれのタイミングでもよく、粒子形成中、粒子形成後脱塩前、脱塩後化学増感前、化学増感後、有機銀塩との混合前のいずれの時期でもよい。好ましくは脱塩後有機銀塩との混合前がよい。増感色素の添加量としては、ハロゲン化銀に対して１×１０^-6モル以上１×１０^-3モル以下が好ましく、更に５×１０^-6モル以上５×１０^-4モル以下が好ましく、特に１×１０^-5モル以上２×１０^-4モル以下が好ましい。増感色素の使用量が多いと残色悪化、保存性悪化、プリントアウトが悪化し好ましくない。
増感色素の使用量は本発明における性能を有する限りにおいては少なくすることが好ましい。
【００５３】
本発明に用いることができる有機銀塩は、光に対して比較的安定であるが、露光された光触媒（写真用銀塩など）および還元剤の存在下で、８０℃またはそれ以上に加熱された場合に銀画像を形成する銀塩である。有機銀塩は、銀イオンを還元できる源を含む任意の有機物質であってよい。有機酸の銀塩、特に（炭素数が１０〜３０、好ましくは１５〜２８の）長鎖脂肪カルボン酸が好ましい。配位子が４．０〜１０．０の範囲の全安定定数を有する有機または無機銀塩の錯体も望ましい。銀源物質は、好ましくは感光性層の約５〜３０重量％を構成すべきである。好ましい有機銀塩は、カルボキシル基を有する有機化合物の銀塩を含む。これらの例は、脂肪族カルボン酸の銀塩および芳香族カルボン酸の銀塩を含むが、これらに限定されない。脂肪族カルボン酸の銀塩の好ましい例は、ベヘン酸銀、ステアリン酸銀、アラキジン酸、オレイン酸銀、ラウリン酸銀、カプロン酸銀、ミリスチン酸銀、パルミチン酸銀、マレイン酸銀、フマル酸銀、酒石酸銀、リノール酸銀、酪酸銀および樟脳酸銀、これらの混合物などを含む。
【００５４】
メルカプトまたはチオン基を含む化合物の銀塩およびこれらの誘導体を使用することもできる。これらの化合物の好ましい例は、３−メルカプト−４−フェニル−１，２，４−トリアゾールの銀塩、２−メルカプトベンズイミダゾールの銀塩、２−メルカプト−５−アミノチアジアゾールの銀塩、２−（エチルグリコールアミド）ベンゾチアゾールの銀塩、Ｓ−アルキルチオグリコール酸（ここで、アルキル基の炭素数は１２〜２２である）の銀塩などのチオグリコール酸の銀塩、ジチオ酢酸の銀塩などのジチオカルボン酸の銀塩、チオアミドの銀塩、５−カルボキシル−１−メチル−２−フェニル−４−チオピリジンの銀塩、メルカプトトリアジンの銀塩、２−メルカプトベンズオキサゾールの銀塩、米国特許第４，１２３，２７４号に記載の銀塩、例えば、３−アミノ−５−ベンジルチオ−１，２，４−チアゾールの銀塩などの１，２，４−メルカプトチアゾール誘導体の銀塩、米国特許第３，３０１，６７８号に記載の３−（３−カルボキシエチル）−４−メチル−４−チアゾリン−２−チオンの銀塩などのチオン化合物の銀塩を含む。さらに、イミノ基を含む化合物の銀塩を使用することができる。これらの化合物の好ましい例は、ベンゾトリアゾールの銀塩およびそれらの誘導体、例えばメチルベンゾトリアゾール銀などのベンゾトリアゾールの銀塩、５−クロロベンゾトリアゾール銀などのハロゲン置換ベンゾトリアゾールの銀塩、米国特許第４，２２０，７０９号に記載のような１，２，４−トリアゾールまたは１−Ｈ−テトラゾールの銀塩、イミダゾールおよびイミダゾール誘導体の銀塩などを含む。例えば、米国特許第４，７６１，３６１号および同第４，７７５，６１３号に記載のような種々の銀アセチリド化合物を使用することもできる。
【００５５】
本発明においては、有機銀塩のための還元剤を併用することが好ましい。本発明に使用できる還元剤としては、銀イオンを金属銀に還元する任意の物質、好ましくは有機物質であってよい。フェニドン、ヒドロキノンおよびカテコールなどの従来の写真現像剤は有用であるが、ヒンダードフェノール還元剤が好ましい。還元剤は、画像形成層の１〜１０重量％として存在すべきである。多層構成において、還元剤をエマルジョン層以外の層に加える場合は、わずかに高い割合である約２〜１５％がより望ましい傾向がある。
【００５６】
熱現像感光材料においては広範囲の還元剤が開示されており、それには、フェニルアミドオキシム、２−チエニルアミドオキシムおよびｐ−フェノキシフェニルアミドオキシムなどのアミドオキシム；例えば４−ヒドロキシ−３，５−ジメトキシベンズアルデヒドアジンなどのアジン；２，２′−ビス（ヒドロキシメチル）プロピオニル−β−フェニルヒドラジンとアスコルビン酸との組合せのような脂肪族カルボン酸アリールヒドラジドとアスコルビン酸との組合せ；ポリヒドロキシベンゼンと、ヒドロキシルアミン、レダクトンおよび／またはヒドラジンの組合せ（例えばヒドロキノンと、ビス（エトキシエチル）ヒドロキシルアミン、ピペリジノヘキソースレダクトンまたはホルミル−４−メチルフェニルヒドラジンの組合せなど）；フェニルヒドロキサム酸、ｐ−ヒドロキシフェニルヒドロキサム酸およびβ−アリニンヒドロキサム酸などのヒドロキサム酸；アジンとスルホンアミドフェノールとの組合せ（例えば、フェノチアジンと２，６−ジクロロ−４−ベンゼンスルホンアミドフェノールなど）；エチル−α−シアノ−２−メチルフェニルアセテート、エチル−α−シアノフェニルアセテートなどのα−シアノフェニル酢酸誘導体；２，２′−ジヒドロキシ−１，１′−ビナフチル、６，６′−ジブロモ−２，２′−ジヒドロキシ−１，１′−ビナフチルおよびビス（２−ヒドロキシ−１−ナフチル）メタンに例示されるようなビス−β−ナフトール；ビス−β−ナフト−ルと１，３−ジヒドロキシベンゼン誘導体（例えば、２，４−ジヒドロキシベンゾフェノンまたは２′，４′−ジヒドロキシアセトフェノンなど）の組合せ；３−メチル−１−フェニル−５−ピラゾロンなどの５−ピラゾロン；ジメチルアミノヘキソースレダクトン、アンヒドロジヒドロアミノヘキソースレダクトンおよびアンヒドロジヒドロピペリドンヘキソースレダクトンに例示されるようなレダクトン；２，６−ジクロロ−４−ベンゼンスルホンアミドフェノールおよびｐ−ベンゼンスルホンアミドフェノールなどのスルホンアミドフェノール還元剤；２−フェニルインダン−１，３−ジオンなど；２，２−ジメチル−７−ｔ−ブチル−６−ヒドロキシクロマンなどのクロマン；２，６−ジメトキシ−３，５−ジカルボエトキシ−１，４−ジヒドロピリジンなどの１，４−ジヒドロピリジン；ビスフェノール（例えば、ビス（２−ヒドロキシ−３−ｔ−ブチル−５−メチルフェニル）メタン、２，２−ビス（４−ヒドロキシ−３−メチルフェニル）プロパン、４，４−エチリデン−ビス（２−ｔ−ブチル−６−メチルフェノール）およビ２，２−ビス（３，５−ジメチル−４−ヒドロキシフェニル）プロパンなど）；アスコルビン酸誘導体（例えば、パルミチン酸１−アスコルビル、ステアリン酸アスコルビルなど）；ならびにベンジルおよびビアセチルなどのアルデヒドおよびケトン；３−ピラゾリドンおよびある種のインダン−１，３−ジオンを含む。
【００５７】
前述の成分に加えて、画像を向上させる「色調剤」として知られる添加剤を含むと有利になることがある。例えば、色調剤材料は全銀保持成分の０．１〜１０重量％の量で存在してよい。色調剤は、米国特許第３，０８０，２５４号、同第３，８４７，６１２号および同第４，１２３，２８２号に示されるように、写真技術において周知の材料である。
【００５８】
色調剤の例は、フタルイミドおよびＮ−ヒドロキシフタルイミド；スクシンイミド、ピラゾリン−５−オン、ならびにキナゾリノン、３−フェニル−２−ピラゾリン−５−オン、１−フェニルウラゾール、キナゾリンおよび２，４−チアゾリジンジオンのような環状イミド；ナフタルイミド（例えば、Ｎ−ヒドロキシ−１，８−ナフタルイミド）；コバルト錯体（例えば、コバルトヘキサミントリフルオロアセテート）；３−メルカプト−１，２，４−トリアゾール、２，４−ジメルカプトピリミジン、３−メルカプト−４，５−ジフェニル−１，２，４−トリアゾールおよび２，５−ジメルカプト−１，３，４−チアジアゾールに例示されるメルカプタン；Ｎ−（アミノメチル）アリールジカルボキシイミド、（例えば、（Ｎ，Ｎ−ジメチルアミノメチル）フタルイミドおよびＮ，Ｎ−（ジメチルアミノメチル）−ナフタレン−２，３−ジカルボキシイミド）；ならびにブロック化ピラゾール、イソチウロニウム誘導体およびある種の光退色剤（例えば、Ｎ，Ｎ′−ヘキサメチレンビス（１−カルバモイル−３，５−ジメチルピラゾール）、１，８−（３，６−ジアザオクタン）ビス（イソチウロニウムトリフルオロアセテート）および２−トリブロモメチルスルホニル）−（ベンゾチアゾール））；ならびに３−エチル−５〔（３−エチル−２−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；フタラジン；フタラジノン、フタラジノン誘導体もしくは金属塩、または４−（１−ナフチル）フタラジノン、６−クロロフタラジノン、５，７−ジメトキシフタラジノンおよび２，３−ジヒドロ−１，４−フタラジンジオンなどの誘導体；フタラジノンとフタル酸誘導体（例えば、フタル酸、４−メチルフタル酸、4-ニトロフタル酸およびテトラクロロ無水フタル酸など）との組合せ；キナゾリンジオン、ベンズオキサジンまたはナフトオキサジン誘導体；トーン調節剤としてだけでなくその場でハロゲン化銀生成のためのハライドイオンの源としても機能するロジウム錯体、例えばヘキサクロロロジウム(III) 酸アンモニウム、臭化ロジウム、硝酸ロジウムおよびヘキサクロロロジウム(III) 酸カリウムなど；無機過酸化物および過硫酸塩、例えば、過酸化二硫化アンモニウムおよび過酸化水素；1,3 −ベンズオキサジン−２，４−ジオン、８−メチル−１，３−ベンズオキサジン−２，４−ジオンおよび６−ニトロ−１，３−ベンズオキサジン−２，４−ジオンなどのベンズオキサジン−２，４−ジオン；ピリミジンおよび不斉−トリアジン（例えば、２，４−ジヒドロキシピリミジン、２−ヒドロキシ−４−アミノピリミジンなど）、アザウラシル、およ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、および１，４−ジ（ｏ−クロロフェニル）−３，６−ジメルカプト−１Ｈ，４Ｈ−２，３ａ，５，６ａ−テトラアザペンタレンなど）を含む。
【００５９】
本発明においてはバッキング層を設けることができる。
本発明のバッキング層の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。バインダーは水又は有機溶媒またはエマルジョンから被覆形成してもよい。
【００６０】
本発明のバッキング層は、７５０〜１４００nmの範囲での最大吸収が０．３以上２以下であることが好ましく、さらに好ましくは０．５以上２以下のＩＲ吸収であり、かつ可視領域においての吸収が０．００１以上０．５未満であることが好ましく、さらに好ましくは０．００１以上０．３未満の光学濃度を有するハレーション防止層であることが好ましい。
【００６１】
本発明でハレーション防止染料を使用する場合、該染料は７５０〜１４００nmの範囲で目的の吸収を有し、可視領域での吸収が充分少なく、上記バッキング層の好ましい吸光度スペクトルの形状が得られればいかなる化合物でも良い。例えば、特開平７−１３２９５号、米国特許５，３８０，６３５号記載の化合物、特開平２−６８５３９号公報第１３頁左下欄１行目から同第１４頁左下欄９行目、同３−２４５３９号公報第１４頁左下欄から同第１６頁右下欄記載の化合物があげられるが、本発明はこれに限定されるものではない。
【００６２】
本発明に用いられるハレーション防止染料の好ましい構造を以下に示すが、本発明はこれに限定されない。
【００６３】
【化７】

【００６４】
【化８】

【００６５】
以下に実施例を挙げて本発明をさらに詳細に説明するが、本発明はこれらに限定されるものではない。
【００６６】
【実施例】
実施例１
（ハロゲン化銀粒子Ａの調製）
水９００ml中にゼラチン７．５ｇ及び臭化カリウム１０mgを溶解して温度３５℃、ｐＨを３．０に合わせた後、硝酸銀７４ｇを含む水溶液３７０mlと（９６／４）のモル比の臭化カリウムと沃化カリウムを含む水溶液をｐＡｇ７．７に保ちながらコントロールドダブルジェット法で１０分間かけて添加した。硝酸銀添加開始と同時に５分間かけて K₃IrCl₆を２．３mgを含む水溶液を添加した。その後４−ヒドロキシ−６−メチル−１，３，３ａ，７−テトラザインデン０．３ｇを添加しＮａＯＨでｐＨを５に調整して平均粒子サイズ０．０６μｍ、投影直径面積の変動係数８％、｛１００｝面比率８６％の立方体沃臭化銀粒子を得た。
この乳剤にゼラチン凝集剤を用いて凝集沈降させ脱塩処理後フェノキシエタノール０．１ｇを加え、ｐＨ５．９、ｐＡｇ７．５に調整した。その後６０℃に昇温してチオ硫酸ナトリウム１．３mgとセレン化合物−Ｉを０．４mgとテルル化合物−Ｉを０．３mg添加し１００分間熟成した後に３５℃に急冷して化学増感を終了した。
【００６７】
【化９】

【００６８】
（ハロゲン化銀粒子Ｂ〜Ｄの調製）
ハロゲン化銀粒子Ａの調製において K₃IrCl₆の代わりに (NH₄)₃RhCl₆、K₂RuCl₆ 、K₄Fe(CN)₆ をそれぞれ０．０４mg、１．７mg、５．３mgずつ含有する水溶液を添加した以外はハロゲン化銀粒子Ａの調製とまったく同様にして調製した。平均粒子サイズ、投影直径面積の変動係数、｛１００｝面比率はハロゲン化銀粒子Ａと同じであった。
（有機脂肪酸銀乳剤Ａの調製）
水３００ml中にベヘン酸１０．６ｇを入れ９０℃に加熱溶解し、十分攪拌した状態で１Ｎの水酸化ナトリウム３１．１mlを添加し、そのままの状態で１時間放置した。その後３０℃に冷却し、１Ｎのリン酸７．０mlを添加して十分攪拌した状態でＮ−ブロモこはく酸イミド０．０１ｇを添加した。その後、あらかじめ調製したハロゲン化銀粒子Ａをベヘン酸に対して銀量として１０モル％となるように４０℃に加温した状態で攪拌しながら添加した。さらに１Ｎ硝酸銀水溶液２５mlを２分間かけて連続添加し、そのまま攪拌した状態で１時間放置した。
【００６９】
この乳剤に酢酸エチルに溶解したポリビニルブチラールを添加して十分攪拌した後に静置し、ベヘン酸銀粒子とハロゲン化銀粒子を含有する酢酸エチル相と水相に分離した。水相を除去した後、遠心分離にてベヘン酸銀粒子とハロゲン化銀粒子を採取した。その後東ソー（株）社製合成ゼオライトＡ−３（球状）２０ｇとイソプロピルアルコール２２ccを添加し１時間放置した後濾過した。更にポリビニルブチラール３．４ｇとイソプロピルアルコール２３ccを添加し３５℃にて高速で十分攪拌して分散し有機脂肪酸銀乳剤Ａの調製を終了した。
【００７０】
（有機脂肪酸銀乳剤Ｂ〜Ｄの調製）
有機脂肪酸銀乳剤Ａの調製において、ハロゲン化銀粒子Ａのかわりにハロゲン化銀粒子Ｂ〜Ｄを添加した以外はまったく同様にして有機脂肪酸銀乳剤Ｂ〜Ｄを調製した。
【００７１】
（乳剤層塗布液の調製）
前述の如く調製した有機脂肪酸銀に対して銀１モルあたり下記の薬品を添加して乳剤塗布液とした。
【００７２】
【化１０】

【００７３】
（表面保護層塗布液の調製）
表面保護層塗布液を下記の如く調製した。
セルロースアセテート ２７ｇ
アセトン ３９０ｇ
メタノール ５０ｇ
二酸化珪素（粒径２μｍ） １．５ｇ
化合物 Ｄ １．０ｇ
【００７４】
【化１１】

【００７５】
（バッキング層塗布液の調製）
バッキング層塗布液を下記の如く調製した。
ポリビニルアルコール ２５６ｇ
脱イオン水 ４６ｇ
メタノール ４６ｇ
ハレーション防止染料（17） ０．０５ｇ
ポリメチルメタクリレート（粒径１０μｍ） １５．０ｇ
【００７６】
以上の如く調製したバッキング層塗布液を二軸延伸された厚さ１７５μｍのポリエチレンテレフタレートフィルムに８１０nmの吸光度が１．２となるように塗布した。
【００７７】
（塗布試料の調製）
調製した塗布液をポリエチレンテレフタレートのバッキング層を塗布した反対面に塗布銀量が１．５ｇ／m²となるように塗布し乾燥した。その後表面保護層塗布液をセルロースアセテートが４．０ｇ／m²となるように塗布し乾燥した。こうして塗布試料１〜１４を得た。
【００７８】
また、比較例としてハロゲン化銀粒子Ａの調製において K₃IrCl₆を添加しない以外は全て同様にしてハロゲン化銀粒子Ｅを調製し、塗布試料１と同様にして脂肪酸銀と調製し塗布液を調製し塗布試料５を得た。
【００７９】
（写真性能の評価）
調製した塗布試料１〜５をキセノンフラッシュで露光し、１２８℃５秒間及び１２８℃１０秒間加熱処理し、得られた画像の評価を濃度計により行なった。感度はＤmin より１．０高い濃度を与える露光量の比の逆数で評価した。現像進行はＤmin より１．０高い濃度を与える露光量の比の逆数の差で評価した。
【００８０】
（画像部保存性の評価）
写真性能を評価した試料を直射日光のあたる場所に１０日間放置し、素現部の濃度上昇を濃度計により評価した。
【００８１】
【表１】

【００８２】
比較用塗布試料５に対して金属鎖体をハロゲン化銀粒子中に含有させることにより現像進行が速くなる。しかもまったく驚くべきことに画像部保存性が非常に低く抑えられていることがわかる。
【００８３】
実施例２
（ハロゲン化銀粒子Ｆ〜Ｉの調製）
実施例１のハロゲン化銀粒子Ｃの調製において、 K₂RuCl₆の添加量を０．１７mg、０．５６mg、１．７mg、５．６mgとし、フェノキシエタノール添加直後に増感色素（１２）をハロゲン化銀１モルに対し１×１０^-4モル添加した以外は全てハロゲン化銀粒子Ｃと同様にして平均粒子サイズ０．０６μｍ、投影直径面積の変動係数１０％、｛１００｝面比率８３％の立方体臭化銀粒子Ｆ〜Ｉを得た。
【００８４】
また、ハロゲン化銀粒子の調製から K₂RuCl₆を除いた以外はまったく同様にしてハロゲン化銀粒子Ｊを調製した。
【００８５】
脂肪酸銀乳剤の調製及びバック層の調製は実施例１とまったく同様にして行った。また、比較例として実施例１で用いたハロゲン化銀粒子Ｅを用いて、同様にして脂肪酸銀乳剤を調製し、塗布時に表２で示した量の増感色素（１２）を添加し、それ以外は実施例１と同様の化合物を添加して塗布試料を作成した。ハロゲン化銀粒子Ｅ〜Ｉについては実施例１と同様にして塗布試料を調製した。
【００８６】
（写真性能の評価）
８１０nmダイオードを備えたレーザー感光計で写真材料を露光した後、写真材料を１２８℃１０秒間加熱処理（現像）し、得られた画像の評価（感度と被り）を濃度計により行なった。感度はＤmin より１．０高い濃度を与える露光量の比の逆数で評価した。写真材料の露光面と露光レーザー光の角度は８０deg とした。
【００８７】
（画像部保存性の評価）
写真性能を評価した試料を直射日光のあたる場所に１０日間放置し、素現部の濃度上昇を濃度計により評価した。
【００８８】
（残色の評価）
写真性能を評価した試料を目視評価した。
○……残色はほとんどない。
△……残色あるが許容される。
×……残色大きく不可。
結果を表２に示した。
【００８９】
【表２】

【００９０】
表２により本発明の効果は明らかである。
【００９１】
実施例３
（ハロゲン化銀粒子Ｋ〜Ｏの調製）
実施例１のハロゲン化銀粒子Ａの調製において、硝酸銀と臭化カリウム及び沃化カリウムを添加するときのｐＡｇを変化させてハロゲン化銀粒子の｛１００｝面比率を８８％、７５％、５５％、４０％、１５％と変化させ、フェノキシエタノール添加直後に増感色素（１３）を表３に記載した量添加した以外は全て実施例１と同様にして平均粒径０．０６μｍのハロゲン化銀粒子Ｋ〜Ｏを調製した。またハロゲン化銀粒子Ｋの調製において温度を６５℃とした以外はまったく同様にして平均粒径０．１５μｍのハロゲン化銀粒子Ｐを調製した。また実施例２と同様にして塗布試料１４〜２１を調製した。各性能の評価は実施例２と同様に行なった。
【００９２】
（経時保存性の評価）
それぞれの塗布試料を３０．５cm×２５．４cmに裁断し角を内径０．５cmのラウンドコーナーとし、２５℃６０％ＲＨ条件下３時間放置したものを１０枚ずつ防湿材料でできた袋の中に入れて密封し、５０℃で５日間経時した（強制経時）。この試料と比較用に保存温度を４℃とした以外は強制経時と同様にした試料とを写真性能の評価と同様の処理を行ない、被り部分の濃度を測定した。経時性はカブリ増加率として評価した。
（カブリ増加率）＝〔｛（強制経時試料のカブリ）−（比較試料のカブリ）｝／｛（比較試料の最高濃度）−（支持体濃度）｝〕×１００
結果を表３に示す。
【００９３】
【表３】

【００９４】
表３からわかるように、本発明においては感光性ハロゲン化銀粒子の表面に占める｛１００｝面比率が高いと非常に優れた性能を有する。また、本発明の範囲内において、感度、保存性、Ｄmax 、残色、プリントアウト濃度いずれの性能も良好である。
【００９５】
【発明の効果】
本発明により、画像形成能にすぐれ、かつ画像形成後の保存性にすぐれた熱現像感光材料が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photothermographic material, and more particularly to a photothermographic material having excellent photographic performance and extremely excellent image portion storage stability.
[0002]
[Prior art]
In recent years, in the medical field, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental protection and space saving. Therefore, the present invention relates to a photothermographic material for medical diagnosis and photographic technology that can be efficiently exposed by a laser image setter or a laser imager and can form a clear black image having high resolution and sharpness. Technology is needed. These photothermographic materials eliminate the use of solution processing chemicals, and can provide customers with a simpler heat treatment system that does not damage the environment.
[0003]
The photothermographic material containing photosensitive silver halide grains is constituted by containing photosensitive silver halide grains, a non-photosensitive reducing silver source, a reducing agent for the silver source, and a binder. Generally, the photosensitive material (photosensitive silver halide grains in the present invention) needs to be in catalytic proximity to the non-photosensitive silver source. Catalytic proximity refers to the close physics of these two materials so that when silver nuclei are formed by silver halide irradiation or exposure, these nuclei can catalyze the reduction of the silver source by the reducing agent. To have a relevance. It has been understood for many years that silver is a catalyst for the reduction of silver ions and that the photosensitive silver halide catalyst precursor that produces silver can be catalytically provided with the silver source in many different ways. For example, partial metathesis of a silver source using a halogenated source (eg, US Pat. No. 3,457,075), a mixture of silver halide and a silver source material (eg, US Pat. No. 3,839,049) And all other methods of closely relating the silver halide and silver source.
[0004]
On the other hand, the photothermographic material contains silver halide that can form silver nuclei by light irradiation or exposure, and there is no fixing or stabilization process. In the case of handling with a silver halide, coloration due to so-called baking of silver halide or an increase in concentration has been a problem. As a technique for solving this problem, for example, Research Disclosure, June 1978, Section 17029 discloses sulfur-containing compounds such as mercaptans, thiones and thioethers. U.S. Pat. Nos. 4,245,033, 4,837,141, and 4,451,561 include sulfur compounds as development inhibitors, and U.S. Pat. No. 4,128,557. Japanese Patent No. 4,137,079 discloses 3-amino-5-benzothio-1,2,4-triazole compounds as stabilizers after image formation.
[0005]
However, the above techniques are excellent techniques for storage under indoor light after image formation, but when such stabilizers are added, heat exposure during processing, photographic sensitivity and density, contrast, etc. There is a problem of affecting photographic properties, and a stabilization technique after image formation that has little influence on photographic properties has been desired.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a photothermographic material having excellent photographic performance and improved storage stability after image formation.
[0007]
[Means for Solving the Problems]
  The present invention has achieved the above object by the method described below.
(1) In a photothermographic material having a photosensitive layer containing an organic silver salt and a photosensitive silver halide on a support,
  In the photosensitive silver halide grains, photosensitive silver halide grains containing at least one metal complex selected from rhodium, ruthenium, osnium, rhenium, iridium, cobalt or iron are mixed with an organic silver salt,
70% or more of the substantial surface area of the photosensitive silver halide grains consists of {100} faces,
A photothermographic material, wherein the photosensitive silver halide grains are chemically sensitized with a chalcogen compound.
[0008]
(2)The photothermographic material according to (1), wherein the photosensitive silver halide grains are spectrally sensitized with a spectral sensitizing dye in any wavelength range of 750 nm to 1400 nm.
[0009]
(3) In a photothermographic material having a photosensitive layer containing an organic silver salt and a photosensitive silver halide on a support,
  In the photosensitive silver halide grains, photosensitive silver halide grains containing at least one metal complex selected from rhodium, ruthenium, osnium, rhenium, iridium, cobalt or iron are mixed with an organic silver salt,
70% or more of the substantial surface area of the photosensitive silver halide grains consists of {100} faces,
  Photosensitive silver halide grains are spectral sensitizing dyesDepending on the wavelength range of 750nm to 1400nmSpectrally sensitized particles,
IR absorption with a maximum absorption in the range of 750 to 1400 nm on the side of the support that does not have a photosensitive layer in the range of 750 to 1400 nm and an optical density of 0.001 to less than 0.5 in the visible region A photothermographic material comprising an antihalation layer having the above-mentioned property.
[0010]
(4) The photosensitive photographic material for heat development according to (1) to (3), wherein the average grain size of the photosensitive silver halide grains is in the range of 0.03 μm to 0.11 μm.
[0011]
(5)The photothermographic material according to (3), wherein the photosensitive silver halide grains are grains chemically sensitized with a chalcogen compound.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The photosensitive material of the present invention has a photosensitive layer containing at least one photosensitive silver halide and an organic silver salt on one side of the support. A so-called single-sided photosensitive material having a backing layer on the other side is preferable, and a photosensitive material that forms an image by heat treatment.
[0013]
The photosensitive silver halide grain of the present invention contains at least one metal complex of a metal selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt, or iron. One kind of these rhodium, rhenium, ruthenium, osmium, iridium, cobalt, or iron metal complexes may be used, or two or more kinds of the same metal and different metal complexes may be used in combination. This content is 1 × 10 to 1 mole of silver.^-9Mol ~ 1 × 10^-2The molar range is preferred, more preferably 1 × 10^-8~ 1x10^-FourA molar range is preferred.
These metal complexes are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains, and any of them before and after the preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical sensitization. Although it may be added at a stage, it is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and particularly preferably at the stage of nucleation. . The metal complex of the present invention may be divided and added several times, and can be uniformly contained in the silver halide grains. Japanese Patent Laid-Open Nos. 63-29603, 2-306236, As described in JP-A-3-167545, JP-A-4-76534, JP-A-6-110146, JP-A-5-273683, and the like, it can also be contained in a particle with a distribution. Preferably, a distribution can be provided inside the particles.
[0014]
These metal complexes can be added by dissolving in water or an appropriate organic solvent miscible with water (for example, alcohols, ethers, glycols, ketones, esters, amides, etc.). A method of adding an aqueous solution dissolved together with powder of the complex or NaCl, KCl to the water-soluble salt or water-soluble halide solution during particle formation, or the third method when the silver salt and the halide solution are mixed simultaneously. Add as a solution and prepare silver halide grains by the method of three-liquid simultaneous mixing, add a required amount of aqueous solution of metal complex to the reaction vessel during grain formation, or dope rhodium in advance when preparing silver halide There is a method of adding another silver halide grain and dissolving it. In particular, a method of adding a powder or an aqueous solution dissolved together with NaCl and KCl to the water-soluble halide solution is preferable.
In order to add to the particle surface, a necessary amount of an aqueous solution of a metal complex can be added to the reaction vessel immediately after the formation of the particle, during or after the physical ripening, or at the chemical ripening.
The amount of these metal complexes added varies depending on the type of ligand, but is 1 × 10 10 per mole of silver halide.^-8Mol ~ 5x10^-3The molar range is preferred, particularly preferably 5 × 10^-8Mol ~ 1 × 10^-FourIs a mole.
[0015]
As the rhodium compound used in the present invention, a water-soluble rhodium compound can be used. For example, a rhodium (III) halide compound or a rhodium complex salt having halogen, amines, oxalato, etc. as a ligand, such as hexachlororhodium (III) complex salt, hexabromorhodium (III) complex salt, hexaammine rhodium ( III) Complex salts, trizalatodium (III) complex salts, hexacyanorhodium (III) complex salts and the like.
[0016]
Rhenium, ruthenium, and osmium used in the present invention are added in the form of water-soluble complex salts described in JP-A-63-2042, JP-A-1-2855941, JP-A-2-20852, JP-A-2-20855, and the like. The Particularly preferred is a hexacoordination complex represented by the following formula.
[ML₆]^-n
Here, M represents Ru, Re, or Os, and n represents 0, 1, 2, 3, or 4.
In this case, the counter ion has no significance and ammonium or alkali metal ions are used.
Preferable ligands include a halide ligand, a cyanide ligand, a cyan oxide ligand, a nitrosyl ligand, a thionitrosyl ligand, and the like. Although the example of the specific complex used for this invention below is shown, this invention is not limited to this.
[0017]
[ReCl₆]^-3        [ReBr₆]^-3          [ReCl_Five(NO)]^-2
[Re (NS) Br_Five]^-2    [Re (NO) (CN)_Five]^-2    [Re (O)₂(CN)_Four]^-3
[RuCl₆]^-3        [RuCl_Four(H₂O)₂ ]^-1    [RuCl_Five(NO)]^-2
[RuBr_Five(NS)]^-2    [Ru (CN)₆]^-Four        [Ru (CO)_ThreeCl_Three]^-2
[Ru (CO) Cl_Five]^-2    [Ru (CO) Br_Five ]^-2
[OsCl₆ ]^-3        [OsCl_Five(NO)]^-2      [Os (NO) (CN)_Five]^-2
[Os (NS) Br_Five]^-2    [Os (CN)₆]^-Four        [Os (O)₂(CN)_Four]^-Four
[0018]
Various iridium complexes can be used in the present invention. For example, hexachloroiridium (III) complex salt, hexachloroiridium (IV) complex salt, hexabromoiridium (III) complex salt, hexabromoiridium (IV) complex salt, hexaiodo Examples include iridium (III) complex salts, hexaiodoiridium (IV) complex salts, hexaammineiridium (III) complex salts and hexaammineiridium (IV) complex salts, hexacyanoiridium (III) complex salts, trioxalatoiridium complex salts, and hexacyanoiridium complex salts. .
[0019]
Although various cobalt and iron compounds can be used in the present invention, hexacyano metal complexes are particularly preferred. Specific examples are shown below.
[Fe (CN)₆]^Four-
[Fe (CN)₆]^3-
[Co (CN)₆]^3-
[0020]
In the present invention, it is particularly preferable to use a metal complex of rhodium, ruthenium, or iridium among the metal complexes (metal compounds). These metal complexes may be used alone or in combination of two or more. In a preferred embodiment of the present invention, when the silver halide grains have a core-shell structure, the core part preferably contains a rhodium compound or a ruthenium compound, and the shell part preferably contains an iridium compound. When the silver halide grains have a uniform halogen composition, the rhodium compound or ruthenium compound is preferably present at a high concentration inside the grain, and the iridium compound is present at a higher concentration near the surface than inside the grain. preferable.
[0021]
The present invention is characterized in that a photosensitive silver halide containing a metal complex is mixed with an organic silver salt after containing. The mixing ratio is preferably 0.01 mol or more and 0.5 mol or less, more preferably 0.02 mol or more and 0.3 mol or less, and more preferably 0.03 mol or more with respect to 1 mol of silver of the organic silver salt. 0.25 mol or less is particularly preferable.
[0022]
The mixing method and mixing conditions of the photosensitive silver halide and the organic silver salt are not particularly limited as long as the effects of the present invention are sufficiently exhibited, but the preferable mixing method is a photosensitive silver halide prepared separately. And a method of mixing the photosensitive silver halide which has been prepared at any timing during the preparation of the organic silver salt, and a more preferable mixing method is a method of mixing the photosensitive silver halide having been prepared. There is a method in which a basic silver halide is mixed with an organic acid, and then the organic acid is silver chlorided.
[0023]
The photosensitive silver halide grains used in the present invention will be described.
The photosensitive silver halide grains in the present invention are used as an optical sensor, and in order to keep the white turbidity after image formation low and to obtain good image quality, the smaller average grain size is preferably 0.20 μm or less. Preferably it is 0.02 micrometer or more and 0.15 micrometer or less, More preferably, 0.03 micrometer or more and 0.11 micrometer or less are good. The grain size here means the length of the edge of the silver halide grain when the silver halide grain is a so-called normal crystal of a cube or octahedron. In addition, when the silver halide grains are not normal crystals, for example, in the case of spherical grains, rod-shaped grains, or tabular grains, the diameter when considering a sphere equivalent to the volume of the silver halide grains.
[0024]
The shape of the photosensitive silver halide grains used in the present invention is not particularly limited, but the proportion of the Miller index {100} plane is preferably high, preferably 50% or more, more preferably 70% or more, and particularly Preferably it is 80% or more.
[0025]
The ratio of the Miller index {100} plane is based on T.Tani, J. Imaging Sci., 29, 165 (1985) using the adsorption dependence of {111} and {100} planes in the adsorption of sensitizing dyes. Can be sought.
[0026]
The halogen composition is not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide, preferably silver bromide or Silver iodobromide is good.
[0027]
Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%, more preferably from 0.1 mol% to 10 mol%. The distribution of the halogen composition in the particles may be uniform, the halogen composition may be changed stepwise, or the particles may be continuously changed. An embodiment using silver halide grains having a core / shell structure with a high silver iodide content in the grains is preferred.
[0028]
The photosensitive silver halide grains of the present invention may not be washed with water or may be washed with water to remove soluble salts.
[0029]
The photosensitive silver halide grains used in the present invention can be chemically sensitized. In particular, chemical sensitization with a chalcogen compound can be performed. Chemical sensitization with chalcogen compounds includes sulfur sensitization, selenium sensitization, and tellurium sensitization.
[0030]
As the sulfur sensitizer used in the present invention, various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanines and the like can be used in addition to the sulfur compounds contained in gelatin. Specific examples are U.S. Pat. Nos. 1,574,944, 2,278,947, 2,410,689, 2,728,668, 3,501,313, 3,656,955. Is described in the issue.
[0031]
As the selenium sensitizer used in the present invention, selenium compounds disclosed in conventionally known patents can be used. That is, usually, an unstable selenium compound and / or a non-labile selenium compound is added, and the emulsion is stirred at a high temperature, preferably 40 ° C. or higher, for a predetermined time. As the unstable selenium compound, compounds described in JP-B-41-15748, JP-B-43-13489, JP-A-4-25832, JP-A-4-109240, JP-A-7-128768 are preferably used. . Specific examples of unstable selenium sensitizers include isoselenocyanates (for example, aliphatic isoselenocyanates such as allyl isoselenocyanate), selenoureas, selenoketones, selenoamides, and selenocarboxylic acids (for example, 2- Selenopropionic acid, 2-selenium butyric acid), selenoesters, diacyl selenides (eg, bis (3-chloro-2,6-dimethoxybenzoyl) selenide), selenophosphates, phosphine selenides, colloidal metal selenium, etc. can give.
[0032]
Examples of tellurium sensitizers used in the present invention include U.S. Patent Nos. 1,623,499, 3,320,069, 3,772,031, British Patent Nos. 235,211 and 1,121. , 496, 1,295,462, 1,396,696, Canadian Patent No. 800,958, Journal of Chemical Society, Chemical Communication (J. Chem. Soc. Chem. Commun. 635 (1980), ibid 1102 (1979), ibid 645 (1979), Journal of Chemical Society Perkin Transaction (J. Chem. Soc. Perkin Trans.) 1, 2191 (198), etc. It is preferable to use it.
[0033]
As specific tellurium sensitizers, compounds described in JP-A-7-168305 and JP-A-7-128768 can be preferably used.
[0034]
The amount of chalcogen sensitizer used in the present invention is 1 × 10 5 per mole of silver halide.^-81 x 10 moles or more^-2Or less, more preferably 1 × 10^-7More than mole 5 × 10^-3Less than mol is good.
[0035]
The chalcogen sensitizer used in the present invention may be added at any timing during silver halide grain formation, after grain formation and before desalting, but preferably during grain formation or after desalting.
[0036]
In the present invention, the photosensitive silver halide grains are preferably spectrally sensitized with a sensitizing dye.
The sensitizing dye used in the present invention is preferably a dye that spectrally sensitizes silver halide grains in any wavelength range of 750 to 1400 nm when adsorbed on silver halide grains. Specifically, the photosensitive silver halide can be spectrally sensitized with a variety of known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes. Useful cyanine dyes are cyanine dyes having basic nuclei such as thiazoline nucleus, oxazoline nucleus, pyrroline nucleus, pyridine nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus and imidazole nucleus. Useful merocyanine dyes are preferably acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus in addition to the basic nuclei described above. Including. Of the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. In particular, sensitizing dyes used in the present invention include U.S. Pat. Nos. 3,761,279, 3,719,495, 3,877,943, British Patent 1,466,201, JP 1,469,117, JP 1,422,057, JP 3-10391, JP 6-52387, JP 5-34323, JP 6-194781, JP It may be appropriately selected from known dyes such as those described in US Pat. No. 301141 and can be positioned in the vicinity of the photocatalyst by a known method. Special sensitizing dyes are generally about 10 per mole of silver halide.^-FiveIt can be used in an amount from mole to about 1 mole. Also, a desired spectral sensitization spectrum can be obtained by mixing a plurality of dyes.
[0037]
The spectral sensitizing dyes preferably used in the present invention are shown by general formulas below, but the present invention is not limited to these compounds.
[0038]
[Chemical 1]

[0039]
[Chemical 2]

[0040]
[Chemical 3]

[0041]
Where R₁And R₂Each represents an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an allyl group, an aralkyl group, a substituted aralkyl group, or a cycloalkyl group.₁And Z₂Each represents the atoms necessary to complete a 5- or 6-membered heterocycle,^-Represents an anion but R₁And / or R₂X when itself contains an anion^-Shall not exist. M⁺Represents a cation. R_Three, R_FourRepresents an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a cycloalkyl group or R_ThreeAnd R_FourRepresents a cycloalkylene skeleton with a structure in which
[0042]
The structure of the dye in the present invention will be described in further detail.₁And R₂(Same type or different type) can be selected from a group of known substituents of the type contained in the cyanine nitrogen atom of the cyanine dye, but in particular, exactly the same as described in JP-B-51-41061 It can be selected from a group of substituents belonging to the range.
[0043]
Of these, R is used particularly effectively.₁And R₂Substituents are alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl and isobutyl, carboxyalkyl groups such as carboxymethyl, carboxyethyl, carboxypropyl and carboxybutyl, and sulfoalkyls such as sulfoethyl, sulfopropyl and sulfobutyl. Groups, sulfate alkyl groups such as sulfate propyl, sulfate butyl, hydroxyalkyl groups, and N- (methylsulfonyl) -carbamyl-methyl groups, γ- (acetyl-sulfamyl) -butyl groups, etc. Aralkyl groups such as substituted alkyl groups, allyl groups, and benzyl groups, substituted aralkyl groups such as carboxybenzyl and sulfobenzyl, aryl groups such as phenyl groups, substituted aryl groups such as carboxyphenyl and sulfophenyl, cyclo Cycloalkyl groups such as cyclohexyl may be mentioned as examples.
[0044]
Z₁And Z₂(Homogeneous or heterogeneous) each represents an atomic group necessary to complete a 5- or 6-membered heterocyclic ring, and can be arbitrarily selected from the heterocyclic series described in JP-B 51-41061.
[0045]
The representative skeleton includes, for example, thiazole series nuclei such as thiazole, 4-methylthiazole, 4-phenylthiazole, 4,5-dimethylthiazole, benzothiazole, 5-chlorobenzothiazole, 5,6-dimethylbenzothiazole, Benzothiazole series nuclei such as 5,6-dimethoxybenzothiazole, naphtho [2,1-d] thiazole, naphtho [1,2-d] thiazole, 5-methoxynaphtho [1,2-d] thiazole, etc. Naphthothiazole series nuclei, thionaphthene [7,6-d] thiazole series nuclei such as 7-methoxythionaphtheno [7,6-d] thiazole, 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole , Oxazole series nuclei such as 4,5-dimethyloxazole and ben Benzoxazole series nuclei such as oxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 5-hydroxybenzoxazole, and naphtho [1,2-d] Naphthoxazole series nuclei such as oxazole, selenazole series nuclei such as 4-methylselenazole, benzoselenazole series nuclei such as benzoselenazole, 5-methylbenzoselenazole, 5-methoxybenzoselenazole, naphtho [ Naphthoselenazole series nuclei such as 2,1-d] selenazole, thiazoline, thiazoline series nuclei such as 4-methylthiazoline 4,4-bishydroxymethylthiazoline, oxazoline series nuclei, selenazoline series nuclei, quinoline, 6- 4-quinoline series nuclei such as tilquinoline, 6-ethoxyquinoline, 6-naphthoxyquinoline, 1-isoquinoline series nucleus, 3-isoquinoline series nucleus, 3,3-dimethylindolenine, 3,3-dimethyl- 3,3-dialkylindolenin series nuclei such as 5-chloro-indolenin, 3,3,5-trimethylisoindolenine, pyridine series nuclei such as pyridine and 5-methylpyridine, 1-ethyl-5 , 6-dichlorobenzimidazole, 1-hydroxyethyl-5,6-dichlorobenzimidazole, 1-ethyl-5-chlorobenzimidazole, 1-ethyl-5-fluoro-6-cyanobenzimidazole, 1-ethyl-5 Ethylsulfonylbenzimidazole, 1-ethyl-5-methylsulfonylbenzimidazole, Examples of the skeleton group complete a benzimidazole series nucleus such as 1-ethyl-5-trifluoromethylsulfonyl-benzimidazole and 1-ethyl-5-trifluoromethylsulfinylbenzimidazole.
[0046]
X^-Represents an anion such as chlorine ion, bromine ion, iodine ion, perchlorate ion, benzenesulfonate ion, p-toluenesulfonate ion, methyl sulfate ion, ethyl sulfate ion, propyl sulfate ion, R₁And / or R₂Itself an anionic group, eg -SO_Three ^-, -OSO_Three ^-, -COO^-, -SO₂N^--, -SO₂-N^--CO-, -SO₂-N^--SO₂X when including-etc.^-Does not exist.
[0047]
M⁺Represents a cation such as a hydrogen cation, a metal cation, or an inorganic or organic onium cation (ammonium, pyridinium, etc.).
[0048]
In the present invention, R_ThreeAnd R_Four(Same or different) is basically R₁And R₂Can be selected from the group of substituents belonging to the same range. R_ThreeAnd R_FourMay be linked to each other to form a cycloalkylene skeleton such as a cyclohexylene skeleton or a cyclopentylene skeleton. A part of the cycloalkylene skeleton may be substituted with atoms other than carbon atoms such as oxygen and nitrogen, and may form, for example, a morpholine skeleton or a piperazine skeleton.
Examples of the structure of the dye represented by the above general formula are shown below.
[0049]
[Formula 4]

[0050]
[Chemical formula 5]

[0051]
[Chemical 6]

[0052]
In the present invention, it is preferable to adsorb the sensitizing dye to the photosensitive silver halide grains before mixing the photosensitive silver halide and the organic silver salt.
The timing of adding the sensitizing dye to the photosensitive silver halide grains may be any timing. During grain formation, after grain formation, before desalting, after desalting, before chemical sensitization, after chemical sensitization, with organic silver salt Any time before mixing. Preferably after desalting and before mixing with the organic silver salt. The addition amount of the sensitizing dye is 1 × 10 with respect to the silver halide.^-61 x 10 moles or more^-3Mole or less is preferable, and further 5 × 10^-6More than mole 5 × 10^-FourMole or less is preferable, especially 1 × 10^-FiveMore than mole 2 × 10^-FourMolar or less is preferable. When the amount of the sensitizing dye used is large, the residual color deteriorates, the storage stability deteriorates and the printout deteriorates, which is not preferable.
The amount of the sensitizing dye used is preferably reduced as long as it has the performance in the present invention.
[0053]
Organic silver salts that can be used in the present invention are relatively stable to light, but are heated to 80 ° C. or higher in the presence of an exposed photocatalyst (such as a photographic silver salt) and a reducing agent. In this case, the silver salt forms a silver image. The organic silver salt may be any organic material containing a source capable of reducing silver ions. Silver salts of organic acids, particularly long chain fatty carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Also desirable are complexes of organic or inorganic silver salts where the ligand has a total stability constant in the range of 4.0-10.0. The silver source material should preferably constitute about 5-30% by weight of the photosensitive layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of silver salts of aliphatic carboxylic acids include silver behenate, silver stearate, arachidic acid, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, and silver fumarate. Silver tartrate, silver linoleate, silver butyrate and silver camphorate, mixtures thereof, and the like.
[0054]
Silver salts of compounds containing mercapto or thione groups and their derivatives can also be used. Preferred examples of these compounds include silver salt of 3-mercapto-4-phenyl-1,2,4-triazole, silver salt of 2-mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, 2- Silver salt of (ethylglycolamide) benzothiazole, silver salt of thioglycolic acid such as silver salt of S-alkylthioglycolic acid (wherein the alkyl group has 12 to 22 carbon atoms), silver salt of dithioacetic acid, etc. Silver salt of dithiocarboxylic acid, silver salt of thioamide, silver salt of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, silver salt of 2-mercaptobenzoxazole, US Pat. 1, 123,274, for example, silver salts of 3-amino-5-benzylthio-1,2,4-thiazole, , 4-mercaptothiazole derivative silver salt, thione compounds such as silver salt of 3- (3-carboxyethyl) -4-methyl-4-thiazoline-2-thione described in US Pat. No. 3,301,678 Contains silver salt. Furthermore, a silver salt of a compound containing an imino group can be used. Preferred examples of these compounds are silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole, such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole, such as silver 5-chlorobenzotriazole, US Pat. 1,2,4-triazole or silver salt of 1-H-tetrazole as described in US Pat. No. 4,220,709, and silver salts of imidazole and imidazole derivatives. For example, various silver acetylide compounds as described in U.S. Pat. Nos. 4,761,361 and 4,775,613 can also be used.
[0055]
In the present invention, it is preferable to use a reducing agent for the organic silver salt in combination. The reducing agent that can be used in the present invention may be any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent should be present as 1-10% by weight of the imaging layer. In a multi-layer configuration, a slightly higher proportion of about 2-15% tends to be more desirable when the reducing agent is added to layers other than the emulsion layer.
[0056]
A wide variety of reducing agents have been disclosed in photothermographic materials, including amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; for example 4-hydroxy-3,5-dimethoxy Azines such as benzaldehyde azine; combinations of aliphatic carboxylic acid aryl hydrazides such as 2,2'-bis (hydroxymethyl) propionyl-β-phenylhydrazine and ascorbic acid and ascorbic acid; polyhydroxybenzene and hydroxyl Combinations of amines, reductones and / or hydrazines such as combinations of hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine; Hydroxamic acids such as phenyl hydroxamic acid, p-hydroxyphenyl hydroxamic acid and β-arinin hydroxamic acid; combinations of azine and sulfonamidophenol (eg, phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol); Α-cyanophenylacetic acid derivatives such as ethyl-α-cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate; 2,2′-dihydroxy-1,1′-binaphthyl, 6,6′-dibromo-2 Bis-β-naphthol as exemplified by 2,2'-dihydroxy-1,1'-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene Derivatives (eg 2,4-dihydroxybenzophenone or 2 ', 4'-dihydroxyacetophenone and the like); 5-pyrazolones such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone Reductones as exemplified by hexose reductone; Sulfonamide phenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,3-dione and the like Chromane such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 1,4-dihydropyridine such as 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine; bisphenol ( For example, bis (2-hydride Xyl-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2-t-butyl-6-methylphenol) ) And 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane); ascorbic acid derivatives (eg 1-ascorbyl palmitate, ascorbyl stearate); and aldehydes such as benzyl and biacetyl And ketones; 3-pyrazolidone and certain indan-1,3-diones.
[0057]
In addition to the aforementioned components, it may be advantageous to include additives known as “toning agents” that enhance the image. For example, the toning material may be present in an amount of 0.1 to 10% by weight of the total silver retaining component. Toning agents are materials well known in the photographic art as shown in US Pat. Nos. 3,080,254, 3,847,612 and 4,123,282.
[0058]
Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione Cyclic imides such as: naphthalimide (eg, N-hydroxy-1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4 -Mercaptans exemplified by dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryldi Carboximide, (for example, (N, N-dimethyl) Aminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg, N, N′-hexamethylene) Bis (1-carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)-(benzothiazole)); 3-ethyl-5 [(3-ethyl-2-benzothiazolinylidene) -1-methylethylidene] -2-thio-2,4-oxazolidinedione; phthalazine; phthalazinone, phthalazinone derivatives or metal salts, or 4- (1-Naphthyl) phthalazinone, 6-chlorophthalazi , Derivatives of 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione; phthalazinone and phthalic acid derivatives (eg phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetra Quinazolinedione, benzoxazine or naphthoxazine derivatives; rhodium complexes that function not only as tone modifiers but also as a source of halide ions for in situ silver halide formation, such as hexachloro Rhodium (III) ammonium, rhodium bromide, rhodium nitrate and potassium hexachlororhodium (III), etc .; inorganic peroxides and persulfates, such as ammonium peroxide disulfide and hydrogen peroxide; 1,3-benzoxazine -2,4-dione, 8-methyl-1,3-benzoxa Benzoxazine-2,4-diones such as gin-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione; pyrimidines and asymmetric-triazines such as 2,4-dihydroxypyrimidine , 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapenta) And 1,4-di (o-chlorophenyl) -3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene, etc.).
[0059]
In the present invention, a backing layer can be provided.
Suitable binders for the backing layer of the present invention are transparent or translucent and are generally colorless, natural polymer synthetic resins, polymers and copolymers, and other film forming media 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), poly (urethanes) ) Phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. The binder may be formed from water or an organic solvent or emulsion.
[0060]
In the backing layer of the present invention, the maximum absorption in the range of 750 to 1400 nm is preferably 0.3 or more and 2 or less, more preferably IR absorption of 0.5 or more and 2 or less, and absorption in the visible region. Is preferably 0.001 or more and less than 0.5, more preferably an antihalation layer having an optical density of 0.001 or more and less than 0.3.
[0061]
When an antihalation dye is used in the present invention, the dye has a desired absorption in the range of 750 to 1400 nm, has a sufficiently small absorption in the visible region, and can obtain any desired absorbance spectrum shape of the backing layer. It may be a compound. For example, compounds described in JP-A-7-13295 and US Pat. No. 5,380,635, JP-A-2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9, line 3- The compounds described in JP-A-24539, page 14, lower left column to page 16, lower right column can be mentioned, but the present invention is not limited thereto.
[0062]
Although the preferable structure of the antihalation dye used for this invention is shown below, this invention is not limited to this.
[0063]
[Chemical 7]

[0064]
[Chemical 8]

[0065]
The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
[0066]
【Example】
Example 1
(Preparation of silver halide grains A)
After dissolving gelatin (7.5 g) and potassium bromide (10 mg) in 900 ml of water and adjusting the temperature to 35 ° C. and pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate and potassium bromide in a molar ratio of (96/4) An aqueous solution containing potassium iodide and potassium iodide was added over 10 minutes by the controlled double jet method while maintaining pAg 7.7. K for 5 minutes at the same time as the addition of silver nitrate_ThreeIrCl₆An aqueous solution containing 2.3 mg of was added. Thereafter, 0.3 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, and the variation coefficient of the projected diameter area was 8%. , {100} face ratio 86% cubic silver iodobromide grains were obtained.
This emulsion was coagulated and precipitated using a gelatin flocculant, desalted and then 0.1 g phenoxyethanol was added to adjust the pH to 5.9 and pAg 7.5. Thereafter, the temperature was raised to 60 ° C., 1.3 mg of sodium thiosulfate, 0.4 mg of selenium compound-I and 0.3 mg of tellurium compound-I were added and aged for 100 minutes, and then rapidly cooled to 35 ° C. to complete the chemical sensitization. did.
[0067]
[Chemical 9]

[0068]
(Preparation of silver halide grains B to D)
In the preparation of silver halide grains A K_ThreeIrCl₆Instead of (NH_Four)_ThreeRhCl₆, K₂RuCl₆, K_FourFe (CN)₆Were prepared in exactly the same manner as the preparation of silver halide grains A, except that aqueous solutions containing 0.04 mg, 1.7 mg, and 5.3 mg respectively were added. The average grain size, the variation coefficient of the projected diameter area, and the {100} plane ratio were the same as those of the silver halide grain A.
(Preparation of organic fatty acid silver emulsion A)
10.6 g of behenic acid was added to 300 ml of water, dissolved by heating at 90 ° C., 31.1 ml of 1N sodium hydroxide was added with sufficient stirring, and the mixture was left as it was for 1 hour. After cooling to 30 ° C., 7.0 g of 1N phosphoric acid was added and 0.01 g of N-bromosuccinimide was added with sufficient stirring. Thereafter, silver halide grains A prepared in advance were added with stirring in a state heated to 40 ° C. so that the amount of silver was 10 mol% with respect to behenic acid. Further, 25 ml of 1N silver nitrate aqueous solution was continuously added over 2 minutes, and the mixture was left for 1 hour with stirring.
[0069]
To this emulsion, polyvinyl butyral dissolved in ethyl acetate was added and stirred sufficiently, and then allowed to stand to separate into an ethyl acetate phase containing silver behenate grains and silver halide grains and an aqueous phase. After removing the aqueous phase, silver behenate particles and silver halide particles were collected by centrifugation. Thereafter, 20 g of synthetic zeolite A-3 (spherical) manufactured by Tosoh Corp. and 22 cc of isopropyl alcohol were added and left for 1 hour, followed by filtration. Further, 3.4 g of polyvinyl butyral and 23 cc of isopropyl alcohol were added and sufficiently stirred at 35 ° C. and dispersed at a high speed to complete the preparation of organic fatty acid silver emulsion A.
[0070]
(Preparation of organic fatty acid silver emulsions B to D)
Organic fatty acid silver emulsions BD were prepared in exactly the same manner as in the preparation of organic fatty acid silver emulsion A, except that silver halide grains BD were added in place of silver halide grains A.
[0071]
(Preparation of emulsion layer coating solution)
The following chemicals were added per mole of silver to the organic fatty acid silver prepared as described above to prepare an emulsion coating solution.
[0072]
[Chemical Formula 10]

[0073]
(Preparation of surface protective layer coating solution)
A surface protective layer coating solution was prepared as follows.
Cellulose acetate 27g
Acetone 390g
50g of methanol
Silicon dioxide (particle size 2μm) 1.5g
Compound D 1.0g
[0074]
Embedded image

[0075]
(Preparation of backing layer coating solution)
A backing layer coating solution was prepared as follows.
Polyvinyl alcohol 256g
46g of deionized water
Methanol 46g
Antihalation dye (17) 0.05g
Polymethylmethacrylate (particle size 10μm) 15.0g
[0076]
The backing layer coating solution prepared as described above was applied on a biaxially stretched 175 μm thick polyethylene terephthalate film so that the absorbance at 810 nm was 1.2.
[0077]
(Preparation of coated sample)
The amount of silver applied is 1.5 g / m on the opposite side of the coating solution prepared by applying a polyethylene terephthalate backing layer.²It was applied and dried. Then, the surface protective layer coating solution was 4.0 g / m2 of cellulose acetate.²It was applied and dried. Thus, coated samples 1 to 14 were obtained.
[0078]
As a comparative example, in the preparation of silver halide grains A, K_ThreeIrCl₆A silver halide grain E was prepared in the same manner except that No was added, and in the same manner as in the coated sample 1, a fatty acid silver was prepared and a coating solution was prepared to obtain a coated sample 5.
[0079]
(Evaluation of photographic performance)
The prepared coated samples 1 to 5 were exposed with a xenon flash, heated at 128 ° C. for 5 seconds and 128 ° C. for 10 seconds, and the obtained images were evaluated with a densitometer. The sensitivity was evaluated by the reciprocal of the ratio of the exposure amount giving a density 1.0 higher than Dmin. The development progress was evaluated by the difference in the reciprocal of the ratio of the exposure amount giving a density 1.0 higher than Dmin.
[0080]
(Evaluation of image section preservation)
The sample for which the photographic performance was evaluated was left in a place exposed to direct sunlight for 10 days, and the density increase in the actual part was evaluated with a densitometer.
[0081]
[Table 1]

[0082]
The development progress is accelerated by including a metal chain in the silver halide grains with respect to the coated sample 5 for comparison. Moreover, it is quite surprising that it can be seen that the storage stability of the image portion is very low.
[0083]
Example 2
(Preparation of silver halide grains FI)
In the preparation of the silver halide grains C of Example 1, K₂RuCl₆Was added at 0.17 mg, 0.56 mg, 1.7 mg, 5.6 mg, and immediately after the addition of phenoxyethanol, the sensitizing dye (12) was added in an amount of 1 × 10 to 1 mol of silver halide.^-FourCubic silver bromide grains F to I having an average grain size of 0.06 μm, a coefficient of variation of projected diameter area of 10%, and a {100} face ratio of 83% were obtained in the same manner as silver halide grains C except that the molar amount was added. .
[0084]
From the preparation of silver halide grains, K₂RuCl₆A silver halide grain J was prepared in exactly the same manner except that.
[0085]
The fatty acid silver emulsion and the back layer were prepared in the same manner as in Example 1. In addition, a fatty acid silver emulsion was prepared in the same manner using the silver halide grains E used in Example 1 as a comparative example, and the amount of sensitizing dye (12) shown in Table 2 was added during coating. A coated sample was prepared by adding the same compound as in Example 1 except that. For silver halide grains E to I, coated samples were prepared in the same manner as in Example 1.
[0086]
(Evaluation of photographic performance)
After exposing the photographic material with a laser sensitometer equipped with a 810 nm diode, the photographic material was heated (developed) at 128 ° C. for 10 seconds, and the obtained image was evaluated (sensitivity and covering) with a densitometer. The sensitivity was evaluated by the reciprocal of the ratio of the exposure amount giving a density 1.0 higher than Dmin. The angle between the exposure surface of the photographic material and the exposure laser beam was 80 °.
[0087]
(Evaluation of image section preservation)
The sample for which the photographic performance was evaluated was left in a place exposed to direct sunlight for 10 days, and the density increase in the actual part was evaluated with a densitometer.
[0088]
(Evaluation of remaining color)
Samples evaluated for photographic performance were visually evaluated.
○ …… There is almost no residual color.
Δ …… Although there is a residual color, it is acceptable.
× …… Remaining color is not large.
The results are shown in Table 2.
[0089]
[Table 2]

[0090]
Table 2 clearly shows the effect of the present invention.
[0091]
Example 3
(Preparation of silver halide grains K to O)
In the preparation of the silver halide grains A of Example 1, the pAg when adding silver nitrate, potassium bromide and potassium iodide was changed to change the {100} face ratio of the silver halide grains to 88%, 75%, 55 %, 40%, and 15%, and silver halide having an average grain size of 0.06 μm in the same manner as in Example 1 except that the sensitizing dye (13) was added in the amount shown in Table 3 immediately after the addition of phenoxyethanol. Particles K to O were prepared. Further, silver halide grains P having an average particle diameter of 0.15 μm were prepared in exactly the same manner as in the preparation of silver halide grains K except that the temperature was set to 65 ° C. Further, coated samples 14 to 21 were prepared in the same manner as in Example 2. Each performance was evaluated in the same manner as in Example 2.
[0092]
(Evaluation of storage stability over time)
Each coated sample was cut into 30.5cm x 25.4cm, rounded corners with an inner diameter of 0.5cm, and left for 10 hours at 25 ° C and 60% RH in a bag made of moisture-proof material. And sealed for 5 days at 50 ° C. (forced aging). The sample was subjected to the same processing as the evaluation of photographic performance except that the storage temperature was changed to 4 ° C. for comparison, and the density of the covered portion was measured. The aging was evaluated as the fog increase rate.
(Fog increase rate) = [{(fogging of forced aging sample) − (fogging of comparative sample)} / {(maximum concentration of comparative sample) − (support concentration)}] × 100
The results are shown in Table 3.
[0093]
[Table 3]

[0094]
As can be seen from Table 3, in the present invention, when the ratio of {100} face to the surface of the photosensitive silver halide grains is high, the performance is extremely excellent. Within the scope of the present invention, the sensitivity, storage stability, Dmax, residual color, and printout density are all good.
[0095]
【The invention's effect】
According to the present invention, a photothermographic material excellent in image forming ability and excellent in storage stability after image formation is provided.

Claims (5)

In a photothermographic material having a photosensitive layer containing an organic silver salt and a photosensitive silver halide on a support,
In the photosensitive silver halide grains, photosensitive silver halide grains containing at least one metal complex selected from rhodium, ruthenium, osnium, rhenium, iridium, cobalt or iron are mixed with an organic silver salt,
70% or more of the substantial surface area of the photosensitive silver halide grains consists of {100} faces,
A photothermographic material, wherein the photosensitive silver halide grains are chemically sensitized with a chalcogen compound. 2. The photothermographic material according to claim 1, wherein the photosensitive silver halide grains are grains that are spectrally sensitized with a spectral sensitizing dye in any wavelength range of 750 nm to 1400 nm. In a photothermographic material having a photosensitive layer containing an organic silver salt and a photosensitive silver halide on a support,
In the photosensitive silver halide grains, photosensitive silver halide grains containing at least one metal complex selected from rhodium, ruthenium, osnium, rhenium, iridium, cobalt or iron are mixed with an organic silver salt,
70% or more of the substantial surface area of the photosensitive silver halide grains consists of {100} faces,
A photosensitive silver halide grain is spectrally sensitized with a spectral sensitizing dye in any wavelength range of 750 nm to 1400 nm ;
IR absorption with a maximum absorption in the range of 750 to 1400 nm on the side of the support that does not have a photosensitive layer in the range of 750 to 1400 nm and an optical density of 0.001 to less than 0.5 in the visible region A photothermographic material comprising an antihalation layer having the above-mentioned property.   4. The photothermographic material according to claim 1, wherein the average grain size of the photosensitive silver halide grains is in the range of 0.03 [mu] m to 0.11 [mu] m. 4. The photothermographic material according to claim 3, wherein the photosensitive silver halide grains are chemically sensitized with a chalcogen compound.