JP3789607B2 - Shading correction method and image forming apparatus - Google Patents

Description

【００５１】
上記一般式（１）において、Ｍは、アルカリ金属原子、第４級アンモニウム、ピリジニウム、キノリニウム、ジアゾニウム、モルホリニウム、テトラゾリウム、アクリジニウム、ホスホニウム、スルホニウム、オキソスルホニウム、硫黄、酸素、炭素、ハロゲニウム、Ｃｕ、Ａｇ、Ｈｇ、Ｐｄ、Ｆｅ、Ｃｏ、Ｓｎ、Ｍｏ、Ｃｒ、Ｎｉ、Ａｓ、Ｓｅから選択されるカチオンを、ｎは１〜６の整数を、Ｒ¹ 、Ｒ² 、Ｒ³ およびＲ⁴ はそれぞれ、ハロゲン原子、置換または未置換のアルキル基、置換または未置換のアルケニル基、置換または未置換のアルキニル基、脂環基、置換または未置換のアリール基、置換または未置換のアルカリール基、置換または未置換のアリーロキシル基、置換または未置換のアラルキル基、置換または未置換の複素環基、置換または未置換のシリル基を表す。ここで、Ｒ¹ 、Ｒ² 、Ｒ³ およびＲ⁴ は互いに同一でも異なっていてもよく、これらのうち２個以上の基が結合して環状構造をとってもよい。
【００５２】
上記一般式（１）において、ボレートアニオンとしては、テトラエチルボレート、トリイソブチルメチルボレート、ジ−ｎ−ブチル−ジ−ｔ−ブチルボレート、テトラフェニルボレート、テトラ−ｐ−クロロフェニルボレート、トリ−ｍ−クロロフェニル−ｎ−ヘキシルボレート、トリフェニルエチルボレート、トリメチルブチルボレート、トリトリルイソプロピルボレート、トリフェニルベンジルボレート、テトラフェニルボレート、テトラベンジルボレート、トリフェニルフェネチルボレート、トリフェニル−ｐ−クロロベンジルボレート、トリフェニルエテニツブリツボレート、ジ（α−ネフチル）−ジプロピルボレート、トリフェニルシリルトリフェニルボレート、トリトルイルシリルフェニルボレート、トリ−ｎ−ブチル（ジメチルフェニルシリル）ボレート等が例示される。
【００５３】
以下に、一般式（１）で示される有機ボレート塩の一例を示す。
【化２】

【００５４】
記録光Ｌ等の光吸収効率を高めるために、この一般式（１）で示される有機ボレート塩は、分光増感色素として、緑色〜赤色域および赤外吸収色素と併用されるのが好ましい。
特に、最大吸収波長を５００nm〜１１００nmの波長領域に有する有機カチオン性色素が好ましく利用され、具体的には、カチオン性メチン色素、カチオン性カルボニウム色素、カチオン性キノンイミン色素、カチオン性インドリン色素、カチオン性スチリル色素が挙げられる。より具体的には、カチオン性のメチン色素としては、ポリメチン色素、シアニン色素、アゾメチン色素、さらに好ましくはシアニン、カルボシアニン、ジカルボシアニン、トリカルボシアニン、ヘミシアニン等が、カチオン性のカルボニウム色素としては、トリアリールメタン色素、キサンテン色素、アリクジン色素、更に好ましくはローダミン等が、カチオン性のキノンイミン色素としては、好ましくはアジン色素、オキサジン色素、チアジン色素、キノリン色素、チアゾール色素等から選ばれた色素が挙げられ、これらは一種又は二種以上を組み合わせて用いることができる。
【００５５】
光重合開始剤としては、より好ましくは、下記一般式（２）で表されるカチオン性色素の有機ボレート塩が利用される。
【００５６】
【化３】

【００５７】
上記一般式（２）において、Ｄ⁺ はカチオン性色素を表し、Ｒ¹ 、Ｒ² 、Ｒ ³およびＲ⁴ は、ハロゲン原子、置換または未置換のアルキル基、置換または未置換のアリール基、置換または未置換のアラルキル基、置換または未置換のアルカリール基、置換または未置換のアルケニル基、置換または未置換のアルキニル基、置換または未置換のアリーロキシル基、置換または未置換のアリサイクリック基、置換または未置換の複素環基、置換または未置換のアリル基、置換または未置換のシリル基、脂環基から選ばれる基である。また、Ｒ¹ 、Ｒ² 、Ｒ³ およびＲ⁴ は互いに同一でも異なっていてもよく、これらのうち２個以上の基が結合して環状構造をとってもよい。
【００５８】
上記一般式（２）において、Ｄ⁺ で表されるカチオン性色素は分光増感色素として作用するものであり、５００nm以上の波長領域、特に５５０nm〜１１００nmの波長領域に吸収ピークを有する有機カチオン性色素が好ましく例示される。
具体的には、カチオン性メチン色素、カチオン性カルボニウム色素、カチオン性キノンイミン色素、カチオン性インドリン色素、カチオン性スチリル色素が挙げられ、より具体的には、カチオン性のメチン色素としては、好ましくはポリメチン色素、シアニン色素、アゾメチン色素、更に好ましくはシアニン、カルボシアニン、ジカルボシアニン、トリカルボシアニン、ヘミシアニン等が、カチオン性のカルボニウム色素としては、好ましくはトリアリールメタン色素、キサンテン色素、アリクジン色素、更に好ましくはローダミン等が、カチオン性のキノンイミン色素としては、好ましくはアジン色素、オキサジン色素、チアジン色素、キノリン色素、チアゾール色素等から選ばれた色素が挙げられる。
また、ボレートアニオンとしては、前記一般式（１）と同じものが好適に例示される。
【００５９】
以下に、一般式（２）で示されるカチオン性色素の有機ボレート塩の一例を示す。
【化４】

【００６０】
【化５】

【００６１】
これらの光重合開始剤の含有量は、光硬化性組成物（熱応答性マイクロカプセル外）の全重量基準で、好ましくは０．０１重量％〜２０重量％である。
【００６２】
この熱発色記録材料においては、前述の光重合開始剤や分光増感色素と共に、下記一般式（３）、一般式（４）で表される、分子内に活性ハロゲン基を有する化合物を助剤として併用することができる。
【００６３】
【化６】

一般式（３）において、Ｘはハロゲン原子を、Ｙ¹ は−ＣＸ₃ 、−ＮＨ₂ 、−ＮＨＲ、−ＮＲ₂ 、−ＯＲを表す。ここで、Ｒはアルキル基、置換アルキル基、アリール基、置換アリール基を表す。また、Ｙ² は−ＣＸ₃ 、アルキル基、置換アルキル基、アリール基、置換アリール基、置換アルケニル基を表す。置換基は、一般式（３）自身であっても良い。
【００６４】
【化７】

一般式（４）において、Ｘはハロゲン原子を表す。Ｙ³ 、Ｙ⁴ は同じでも異なってもよく、水素原子又はハロゲン原子を表す。また、Ｚは下記式で示す基を表す。
【化８】

ここで、Ｒ¹ は水素原子、ハロゲン原子、アルキル基、置換アルキル基、アリール基、置換アリール基、置換アルケニル基、複素環基、置換複素環基を表す。
【００６５】
また、一般式（３）で表される化合物としては、Ｙ¹ がＣＸ₃ である化合物が好ましく利用される。
具体的には、前記一般式（３）で表される化合物としては、２−フェニル−４，６−ビス（トリクロルメチル）−Ｓ−トリアジン、２−（ｐ−クロルフェニル）−４，６−ビス（トリクロルメチル）−Ｓ−トリアジン、２−（ｐ−メトキシフェニル）−４，６−ビス（トリクロルメチル）−Ｓ−トリアジン、２，４，６−トリス（トリクロルメチル）−Ｓ−トリアジン、２−（ｐ−シアノフェニル）−４，６−ビス（トリクロルメチル）−Ｓ−トリアジン、２−（ｐ−アセチルフェニル）−４，６−ビス（トリクロルメチル）−Ｓ−トリアジン等が好適に例示される。
【００６６】
他方、前記一般式（４）で表される化合物としては、四塩化炭素、四臭化炭素、ヨードホルム、ｐ−ニトロ−α，α，α−トリプロモアセトフェノン、ω，ω，ω−トリプロモキナルジン、トリプロモメチルフエニルスルホン、トリクロロメチルフエニルスルホン等を挙げることができる。
【００６７】
このような一般式（３）または（４）で示される化合物は、分光増感色素（カチオン性色素）１mol に対し、一般式（３）又は（４）で示される化合物は、０．０１mol 〜２０mol 添加するのが好ましい。
【００６８】
第２および第３の記録材料は、高感度でかつ赤外光に感度を有するが、潜像形成を促進するための助剤として、還元剤、例えば、酸素除去剤（oxygen scavenger）および活性水素ドナーの連鎖移動剤、その他の化合物を併用してもよい。
潜像形成を促進するための助剤として有用であることの見いだされている酸素除去剤は、ホスフィン、ホスホネート、ホスファイト、第１錫塩及び、酸素により容易に酸化されるその他の化合物で、例えば、Ｎ−フェニルグルシン、トリメチルバルビツール酸、Ｎ，Ｎ−ジメチル−２，６−ジイソプロピルアニリン等が例示される。
【００６９】
第３の記録材料の光硬化性組成物には、電子受容性化合物が添加される。また、第２の記録材料の光硬化性組成物にも、必要に応じて、電子受容性化合物を添加してもよく、これにより発色濃度を向上できる。
電子受容性化合物としては、、フェノール誘導体、サリチル酸誘導体、芳香族カルボン酸の金属塩、酸性白土、ベントナイト、ノボラック樹脂、金属処理ノボラック樹脂、金属錯体などが挙げられる。なお、フェノール誘導体としては、２，２′−ビス（４−ヒドロキシフェニル）プロパン、４−ｔ−ブチルフェノール、４−フェニルフェノール、４−ヒドロキシジフェニノキシド、１，１′−ビス（３−クロロ−４−ヒドロキシフェニル）シクロヘキサン、１，１′−ビス（３−クロロ−４−ヒドロキシフェニル）−２−エチルブタン等が例示される。また、サリチル酸誘導体としては、４−ペンタデシルサリチル酸、３，５−ジ（α−メチルベンジル）サリチル酸、３，５−ジ（ｔｅｒｔ−オクチル）サリチル酸、５−オクタデシルサリチル酸、５−α−（ｐ−α−メチルベンジルフェニル）エチルサリチル酸、３−α−メチルベンジル−５−ｔｅｒｔ−オクチルサリチル酸、５−テトラデシルサリチル酸等が例示される。
これらの電子受容性化合物は、電子供与性無色染料の５重量％〜１０００重量％程度使用するのが好ましい。
【００７０】
このような第２および第３の記録材料の光硬化性組成物には、これらの化合物の他に、光架橋性組成物として例えばポリケイ皮酸ビニル、ポリシンナミリデン酢酸ビニル、α−フェニルマレイミド基をもつ光硬化性組成物等を添加してもよい。また、これらの光架橋性組成物を光硬化性成分として用いてもよい。
【００７１】
さらに、光硬化性組成物の中には、これらの化合物の他に、必要に応じて、光硬化性組成物の熱的および経時的な重合を防止して、安定性を高めることを目的として、熱重合禁止剤を添加してもよい。
熱重合禁止剤としては、ｐ−メトキシフェノール、ハイドロキノン、ｔ−ブチルカテコール、ピロガロール、２−ヒドロキシベンゾフェノン、４−メトキシ−２−ヒドロキシベンゾフェノン、塩化第一銅、フェノチアジン、クロラニル、ナフチルアミン、β−ナフトール、２，６−ジ−ｔ−ブチル−ｐ−クレゾール、ニトロベンゼン、ジニトロベンゼン、ピクリン酸、ｐ−トルイジン等が好適に例示され、光硬化性組成物の全重量基準で０．００１重量％〜５重量％程度添加するのが好ましい。
【００７２】
光硬化性組成物は、乳化分散されて画像形成層の中に含有される。
光硬化性組成物を乳化分散するために用いられる溶媒としては、綿実油、灯油、脂肪族ケトン、脂肪族エステル、パラフィン、ナフテン油、アルキル化ビフェニル、塩素化パラフィン、１，１′−ジトリルエタン等のジアリールエタン、ジブチルフタレート等のフタール酸アルキルエステル、ジフェニルホスフェート等の燐酸エステル、アセチルクエン酸トリブチル等のクエン酸エステル、安息香酸オクチル等の安息香酸エステル、ジエチルラウリルアミド等のアルキルアミド、酢酸エチル等の酢酸エステル、（メタ）アクリル酸メチル等の（メタ）アクリル酸エステル、メチレンクロライドや四塩化炭素等のアルキルハライド、メチルイソブチルケトン、β−エトキシエチルアセテート、メチルセロソルブアセテート等がある。特に、脂肪族エステル類、アルキルハライド類が好ましく、特に水への溶解度の１０体積％以下のものがより好ましい。
これらの溶媒は、光重合性化合物に対して１重量部〜５００重量部の割合で用いるのが好ましい。
【００７３】
また、光硬化性組成物の乳化分散に用いることのできる水溶性高分子としては、２５℃の水に対して５重量％以上溶解する化合物が好ましく、具体的には、ゼラチン、ゼラチン誘導体、アルブミン等の蛋白質、メチルセルロース等のセルロース誘導体、デンプン類（変成デンプンを含む）等の糖誘導体、ポリビニルアルコール、スチレン−無水マレイン酸共重量体加水分解物、カルボキシ変成ポリビニルアルコール、ポリアクリルアミド、酢酸ビニル−ポリアクリル酸共重合体の鹸化物、ポリスチレンスルホン酸塩糖の合成高分子が挙げられ、特に、ゼラチンおよびポリビニルアルコールが好ましい。
【００７４】
他方、この第２および第３の記録材料の画像形成層のマイクロカプセルに内包される電子供与性の無色染料は、従来より公知のトリフェニルメタンフタリド系化合物、フルオラン系化合物、フェノチアジン系化合物、インドリルフタリド系化合物、ロイコオーラミン系化合物、ローダミンラクタム系化合物、トタフェニルメタン系化合物、トリアゼン系化合物、スピロピラン系化合物、フルオレン系化合物など各種の化合物を使用できる。
具体的には、トリフェニルメタンフタリド系化合物としては３，３−ビス（ｐ−ジメチルアミノフェニル）−６−ジメチルアミノフタリドや３−（ｐ−ジメチルアミノフェニル）−３−（２−メチルインドール−３−イル）フタリド等が；ロイコオーラミン系化合物としてはＮ−ハロフェニル−ロイコオーラミンやＮ−２，４，５−トリクロロフェニルロイコオーラミン等が； ローダミンラクタム系化合物としてはローダミン−Ｂ−アニリノラクタムやローダミン−（ｐ−ニトリノ）ラクタム等が： フルオラン系化合物としては２−（ジベンジルアミノ）フルオランや２−アニリノ−３−メチル−６−ジエチルアミノフルオランや２−アニリノ−３−メチル−６−Ｎ−メチル−Ｎ−シクロヘキシルアミノフルオラン等が； フェノチアジン系化合物としてはベンゾイルロイコンメチレンブルーやｐ−ニトロベンジルロイコメチレンブルー等が； スピロピラン系化合物としては３−メチル−スピロ−ジナフトピランや３，３′−ジクロロ−スピロ−ジナフトピラン等が； それぞれ例示される。
【００７５】
このような電子供与性無色染料を内包するマイクロカプセルは、当業界で公知の方法を用いて得ることができる。
例えば、米国特許第２，８００，４５７号明細書に開示される親水性壁形成材料のコアセルベーションを利用する方法、特公昭４２−７７１号公報に開示される界面重合法、米国特許第３，６６０，３０４号明細書に開示されるポリマーの析出による方法、米国特許第３，７９６，６６９号明細書に開示されるイソシアネートポリオール壁材料を用いる方法、米国特許第３，９１４，５１１号明細書に開示されるイソシアネート壁材料を用いる方法、米国特許第４，０８９，８０２号明細書に開示される尿素ホルムアルデヒド−レゾルシノール系壁形成材料等を用いる方法等が開示される。特に、芯物質を乳化した後マイクロカプセル壁として高分子膜を形成することが好ましい。
【００７６】
中でも特に、油滴内部からのリアクタントの重合によるマイクロカプセル化法が、短時間内に、均一な粒径のカプセルを持ち、かつ保存性にすぐれた記録材料が得られる点で好ましい。
例えば、ポリウレタンをカプセル壁材として用いる場合には、多価イソシアネートおよびそれと反応してカプセル壁を形成する第２の物質（例えば、ポリオール、ポリアミン）をカプセル化すべき油性液体中に混合し水中に乳化分散し次に温度を上昇することにより、油滴界面で高分子形成反応を起こして、マイクロカプセル壁を形成する。このとき油性液体中に低沸点の溶解力の強い補助溶剤を用いることができる。
【００７７】
この場合に用いる多価イソシアネートとしては、ｍ−フェニレンジイソシアネート、２，６−トリレンジイソシアネート、２，４−トリレンジイソシアネート、ジフェニルメタン−４，４−ジイソシアネート、キシリレン−１，４−ジイソシアネート、４，４′−ジフェニルプロパンジイソシアネート、トリメチレンジイソシアネート、ヘキサメチレンジイソシアネート等、公知のウレタン樹脂の製造に用いられる多価イソシアネートが各種利用可能である。なお、多価イソシアネートは水と反応して高分子物質を形成することもできる。
また、ポリオールとしては、脂肪族、芳香族の多価アルコール、ヒドロキシポリエステル、ヒドロキシポリアルキレンエーテル等で、具体的には、エチレングリコール、１，３−プロパンジオール、１，４−プタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、プロピレングリコール、２，３−ジヒドロキシブタン、１，２−ジヒドロキシブタン、２，５−ヘキサンジオール、３−メチル−１，５−ペンタンジオール、ジヒドロキシシクロヘキサン等、公知のウレタン樹脂の製造に用いられるポリオールが各種利用可能である。なお、ポリオールはイソシアネート基１mol に対して、水酸基の割合が０．０２mol 〜２mol 程度使用するのが好ましい。
さらに、ポリアミンとしてはエチレンジアミン、トリメチレンジアミン、テトラメチレンジアミン、ペンタメチレンジアミン、ヘキサメチレンジミアン、ｐ−（ｍ−）フェニレンジアミン、ピペラジンおよびその誘導体、２−ヒドロキシトリメチレンジアミン、ジエチレントリアミン、トリエチレントリアミン、トリエチレンテトラミン、テトラエチレンペンタミン、エポキシ化合物のアミン付加物等が挙げられる。
【００７８】
マイクロカプセルは、水溶性高分子を用いて作製することもできる。この際の水溶性高分子は水溶性のアニオン性高分子、ノニオン性高分子、両性高分子のいずれでも良い。
アニオン性高分子としては、−ＣＯＯ−、−ＳＯ₂ −基等を有するものが挙げられ、具体的には、アラビヤゴム、アルギン酸、硫酸化デンプン、硫酸化セルローズ、フタル化ゼラチン等のゼラチン誘導体、（メタ）アクリル酸系（共）重合体、ビニルベンゼンスルホン酸系（共）重合体、カルボキシ変成ポリビニルアルコール等が、ノニオン性高分子としては、ポリビニルアルコール、ヒドロキシエチルセルロース等が、両性の化合物としてはゼラチン等が例示され、特に、ゼラチン、ゼラチン誘導体、ポリビニルアルコールが好ましい。
水溶性高分子は０．０１重量％〜１０重量％の水溶液として用いられる。
【００７９】
このような第２および第３の記録材料において、カプセルの平均粒子径は２０μｍ以下、特に解像度の点から５μｍ以下が好ましい。またカプセルが小さすぎる場合には一定固形分に対する表面積が大きくなり多量の壁剤が必要となる。このため０．１μｍ以上が好ましい。
【００８０】
電子供与性無色染料は、マイクロカプセル中に溶液状態で存在してもよく、あるいは、固体の状態で存在してもよい。
溶液状態で電子供与性無色染料を存在させる場合は、この染料を溶媒に溶解した状態でカプセル化すればよい。この時の溶媒の量は電子供与性無色染料１００重量部に対して１重量部〜５００重量部の割合が好ましい。カプセル化の時に用いる溶媒としては、前記光硬化性組成物の乳化に用いる溶媒と同様のものを用いることができる。また、マイクロカプセル化の時、電子供与性無色染料を溶解するための補助溶剤として、酢酸エステル系の溶媒等の揮発性の溶媒を他の溶媒と併用してもよい。
【００８１】
この第２および第３の記録材料は、画像形成層以外にも、保護層や中間層等の各種の層を有してもよいが、保護層中にはマット剤を添加する事が好ましい。
マット剤としては、例えばシリカや酸化マグネシウム等の無機粒子、ポリメチルメタクリレートやポリスチレン等の樹脂粒子、カルボキシ澱粉等の澱粉粒子などが例示され、特に、ポリメチルメタクリレート粒子とシリカ粒子が好ましく利用される。シリカ粒子としてはFUJI-DEVISON CHEMICAL LTD.製のサイロイドＡＬシリーズ等が利用可能である。
マット剤の粒子径は１μｍ〜２０μｍが好ましく、また、添加量としては２mg/m² 〜５００mg/m² が好ましい。
【００８２】
この記録材料の画像形成層、中間層および保護層の各層には、硬化剤を併用することが好ましい。特に保護層中に硬化剤を併用し、保護層の粘着性を低減する事が好ましい。
硬化剤としては、写真記録材料の製造に用いられる「ゼラチン硬化剤」が有用であり、具体的には、クロムミョウバン、硫酸ジルコニウム、硼酸、１，３，５−トリアクロイル−ヘキサヒドロ−ｓ−トリアジン、１，２−ビスビニルスルホニルメタン、１，３−ビス（ビニルスルホニルメチル）プロパノール−２、ビス（α−ビニルスルホニルアセトアミド）エタン、２，４−ジクロロ−６−ヒドロキシ−ｓ−トリアジン・ナトリウム塩、２，４，６−トリエチレニミノ−ｓ−トリアジン等が好適に例示される。
なお、各層における硬化剤の添加量は、バインダーに対して０．５重量％〜５重量％程度が好ましい。
【００８３】
また、保護層には、その粘着性を低下させるためにコロイダルシリカを添加してもよい。
コロイダルシリカとしては、例えば、日産化学製のスノーテックス２０、スノーテックス３０、スノーテックスＣ、スノーテックスＯ、スノーテックスＮ等が利用可能であり、添加量は、バインダーに対して５重量％〜８０重量％程度が好ましい。
さらに、保護層には記録材料の白色度をあげるための蛍光増白剤やブルーイング剤としての青色染料を添加してもよい。
【００８４】
この第２および第３の記録材料を多色記録材料とする際には、例えば、異なる色相に発色する電子供与性無色染料を含有するマイクロカプセルと異なる波長の光に感光する光硬化性組成物を各層に含む多層の記録材料の構成を用い、かつ、感光・感熱層の間にフィルター色素を含有する中間層を設けてもよい。
中間層は主にバインダーとフィルター色素より成り、必要に応じて硬化剤やポリマーラテックス等の添加剤を含有することができる。
フィルター用色素は水中油滴分散法やラテックス分散法により乳化分散して所望の層とくに中間層に添加できる。水中油滴分散法では、沸点が例えば１７５℃以上の高沸点有機溶媒および例えば沸点が３０℃〜１６０℃のいわゆる補助溶媒のいずれか一方の単独液または両者混合液に溶解した後、界面活性剤の存在下に水やゼラチン水溶液等の水性媒体中に微細分散する。
ラテックス分散法の工程、硬化および含浸用のラテックスの具体例は米国特許第４，１９９，３８３号明細書等に記載されており、適当なラテックスとしては、例えば、エチルアクリエレート等の（メタ）アクリル酸エステルとアクリル酸等の酸モノマーの共重合ラテックスが好ましい。
【００８５】
この第２および第３の記録材料において、保護層、画像形成層、中間層等の各層のバインダーとしては、光硬化性組成物の乳化分散や、電子供与性無色染料のカプセル化に用いられる水溶性高分子の他、ポリスチレン、ポリビニルホルマール、ポリビニルブチラール、ポリビニルアルコール、ポリメチルアクリレート等のアクリル樹脂、フェノール樹脂、エチルセルロース、エポキシ樹脂、ウレタン樹脂等の溶剤可溶性高分子あるいはこれらの高分子ラテックスを用いることもできる。これらの中ではゼラチンおよびポリビニルアルコールが好ましい。
【００８６】
また、この第２および第３の記録材料の各層には塗布助剤、帯電防止、スベリ性改良、乳化分散、接着防止等の目的で界面活性剤を用いてもよい。
界面活性剤としては例えば非イオン性界面活性剤であるサポニン、ポリエチレンオキサイドおよびその誘導体、アルキルスルホン酸塩、アルキル硫酸エステル、Ｎ−アシル−Ｎ−アルキルタウリン類等を必要に応じ用いる事ができる。
また、これまで述べた添加剤以外にも、必要に応じて、イラジエーションやハレーションを防止する染剤、紫外線吸収剤、可塑剤、蛍光増白剤、塗布助剤、硬化剤、帯電防止剤や滑り性改良剤等を添加してもよい。
【００８７】
このような記録材料Ａ（第１の記録材料、第２の記録材料、および第３の記録材料）は、各層の成分を含有する塗布液（乳剤）を、必要に応じて溶媒を用いて調製し、公知の手段で塗布して乾燥することにより作製することができる。
溶媒としては、記録材料の作製に用いられる各種の溶媒が利用可能であり、具体的には、水、エタノールやイソプロパノール等のアルコール類、エチレンクロライド等のハロゲン系の溶剤、シクロヘキサノンやメチルエチルケトン等のケトン類、酢酸メチルセロソルブや酢酸エチル等のエステル類、トルエン、キシレン等が例示され、必要に応じて、複数種を混合して用いられ、さらに、塗布性や帯電改良などを目的として、塗布液にノニオン系、アニオン系、カチオン系、フッ素系等の各種の界面活性剤等を添加してもよい。
また、塗布方法としては、ブレードコーター、ロッドコーター、ナイフコーター、ロールドクターコーター、リバースロールコーター、トランスファーロールコーター、グラビアコーター、キスロールコーター、カーテンコーター等の公知の方法が利用可能である。なお、各塗料の塗布量は、乾燥後の各層の付着量が所定量となるように調整されるのは、もちろんである。
【００８８】
これらの記録材料Ａの支持体にも特に限定はなく、通常の記録材料で用いられているものが各種利用可能であり、具体的には、ポリエステルフィルム、ポリエチレンテレフタレート（ＰＥＴ）フィルム、ポリエチレンナフタレートフィルム、硝酸セルロースフィルム、セルロースエステルフィルム、ポリビニルアセタールフィルム、ポリカーボネートフィルム等の樹脂フィルム、アルミニウム、亜鉛、銅等の各種の金属、ガラス、紙等が例示される。
図示例の記録材料Ａは、一例として、透明なＰＥＴフィルムを支持体として用いる、光透過性のフィルム記録材料である。
【００８９】
このような記録材料Ａを用いて、画像データ供給源Ｒから供給された画像データに応じた可視像が記録されたプリント（ハードコピー）を作成する形成装置１０は、基本的に、記録材料Ａの搬送方向順に、感光材料供給部１２と、幅寄せ部１４と、画像露光部１６と、熱現像部１８と、排出トレイ８０とを有して構成される。また、熱現像部１８とトレイ８０との間には、熱現像を終了した記録材料Ａの濃度を測定するための、光源８２およびラインセンサ８４が配置される。
なお、図１においては、図面を簡略化して構成を明瞭にするために省略しているが、形成装置１０には、図示した部材以外にも、記録材料Ａを搬送するための搬送ローラやガイド、各種のセンサ等が必要に応じて配置されている。
【００９０】
記録材料Ａは、通常、１００枚等の所定単位の積層体（束）とされて袋体や帯等で包装されており、通常、この所定単位の積層体のまま専用のマガジン２０に収納されて形成装置１０に供給され、１枚ずつ画像形成に供される。
感光材料供給部１２（以下、供給部１２とする）は、このマガジン２０から記録材料Ａを一枚取り出して、記録材料Ａの搬送方向の下流（以下、下流とする）に位置する幅寄せ部１４に供給する部位で、装填部２２および２４と、各装填部に配置される吸盤２６および２８を用いた枚葉手段ならびに供給ローラ対３０および３２と、搬送ローラ対３４および３６と、搬送ガイド３８，４０および４２とを有して構成される。
【００９１】
装填部２２および２４は、記録材料Ａを収納したマガジン２０を所定位置に装填する部位である。図示例の形成装置１０は、２つの装填部２２および２４を有しており、両装填部には、通常、サイズの異なる（例えば、ＣＴやＭＲＩ用の半切サイズと、ＦＣＲ（富士コンピューテッドラジオグラフィー）用のＢ４サイズ等）記録材料Ａを収納するマガジン２０が装填される。
【００９２】
各装填部に配置される枚葉手段は、吸盤２６および２８によって記録材料Ａを吸着保持して、リンク機構等の公知の移動手段で吸盤２６および２８を移動することによって記録材料Ａを搬送し、それぞれの装填部に配置される供給ローラ対３０および３２に供給する。
供給ローラ対３０に供給された記録材料Ａは、搬送ガイド３８，４０ならびに４２に案内されつつ搬送ローラ対３４ならびに３６によって、他方、供給ローラ対３２に供給され記録材料Ａは、搬送ガイド４０ならびに４２に案内されつつ搬送ローラ対３６によって、それぞれ下流の幅寄せ部１４に搬送される。
【００９３】
幅寄せ部１４は、記録材料Ａを、搬送方向と直交する方向（以下、幅方向とする）に位置合わせすることにより、下流の記録部１６における主走査方向の記録材料Ａの位置合わせ、いわゆるサイドレジストを取って、搬送ローラ対４４によって記録材料Ａを下流の画像露光部１６に搬送する部位である。
幅寄せ部１４におけるサイドレジストの方法には特に限定はなく、例えば、記録材料Ａの幅方向の１端面と当接して位置決めを行うレジスト板と、記録材料Ａを幅方向に押動して端面をレジスト板に当接させる押動手段とを用いる方法、前記レジスト板と、記録材料Ａの搬送方向を幅方向で規制して同様にレジスト板に当接させる、記録材料Ａの幅方向のサイズに応じて移動可能なガイド板等とを用いる方法等、公知の方法が各種例示される。
なお、サイドレジストは、記録材料Ａの幅方向の中心を基準とするいわゆるセンター基準でも、記録材料Ａの幅方向の端部を基準とするいわゆる端面基準であってもよい。
【００９４】
画像露光部１６（以下、露光部１６とする）は、光ビーム走査露光によって記録材料Ａを像様に露光する部位で、露光ユニット４６と副走査搬送手段４８とを有して構成される。
【００９５】
図２に、露光部１６の概念図を示す。
露光ユニット４６は、記録画像に応じて変調した光ビームＬを主走査方向（図１および図２で紙面に垂直方向）に偏向して、所定の記録位置Ｘに入射する、公知の光ビーム走査装置であって、光源５０と、光源５０を駆動する露光制御装置５２と、光偏向器であるポリゴンミラー５４と、ｆθレンズ５６と、立ち下げミラー５８と、シェーディング補正条件算出部８６（以下、条件算出部８６とする）と、データ処理部８８とを有して構成される。
ここで、条件算出部８６は、熱現像部１８すなわち加熱ドラム６８の表面温度ムラ（温度分布）による熱現像ムラに起因する濃度ムラ、すなわちシェーディングを補正するシェーディング補正データ（補正条件）を算出する部位である。
なお、露光ユニット４６には、これ以外にも、光源から射出された光ビームＬを整形するコリメータレンズやビームエキスパンダ、面倒れ補正光学系、光路変更用ミラー等、公知の光ビーム走査装置に配置される各種の部材が必要に応じて配置されている。
【００９６】
光源５０は、記録材料Ａの分光感度特性に応じた狭帯波長域の光ビームＬを射出する光源である。
ＭＲＩやＣＴ等の画像データ供給源Ｒからの画像データは、データ処理部８８に送られる。データ処理部８８は、条件算出部８６から対応する画素のシェーディング補正データを受け取り、これに応じて画像データの補正すなわちシェーディング補正を行う。
なお、条件算出部８６およびデータ処理部８８によるシェーディング補正については、後に詳述する。
【００９７】
データ処理部８８で処理された画像データは、露光制御装置５２に送られる。露光制御装置５２は、供給された画像データすなわち記録画像に応じて光源５０を駆動して、画像データに応じて変調された光ビームＬを射出させる。
また、露光制御部５２は、シェーディング補正データの算出を行う際には、記録材料Ａの全面に渡って所定の一様濃度の画像すなわちベタ画像を形成するように、光源５０を駆動する。
【００９８】
本発明の形成装置１０においては、光ビームＬの変調方法には特に限定はなく、パルス（幅もしくは数）変調であっても強度変調であってもよい。
また、図示例においては、露光制御装置５２によって光源５０の駆動を制御して変調を行う、直接変調によって光ビームＬを記録画像に応じて変調しているが、これ以外にも、ＡＯＭ（音響光学変調器）、ＥＯＭ（電気光学変調器）、液晶シャッタアレイのような空間変調素子等を用いた外部変調でもよい。
【００９９】
このように変調されて光源５０から射出された光ビームＬは、ポリゴンミラー５４によって主走査方向に偏向され、ｆθレンズ５６によって記録位置Ｘで結像するように調光され、立ち下げミラー５８によって光路を変更されて記録位置Ｘに入射する。
なお、図示例の形成装置１０はモノクロの画像記録を行う装置で、露光ユニット４６は光源５０を１つのみ有するが、本発明をカラー画像の記録に利用する際には、例えば、カラー感光材料のＲ（赤）、Ｇ（緑）、およびＢ（青）の分光感度特性に応じた波長の光ビームを射出する３種の光源を有する露光ユニットが用いられる。
【０１００】
一方、副走査搬送手段４８は、記録位置Ｘ（走査線）を挟んで配置される一対の搬送ローラ対６０および６２を有するものであり、搬送ローラ対６０および６２によって、記録材料Ａを記録位置Ｘに保持しつつ、前記主走査方向と直交する副走査方向（図２中矢印ａ方向）に搬送する。
ここで、前述のように、記録画像に応じて変調された光ビームＬは、主走査方向に偏向されているので、記録材料Ａは光ビームによって２次元的に走査露光され、潜像が記録される。
【０１０１】
露光部１６において潜像を記録された記録材料Ａは、次いで、搬送ローラ対６４および６６等によって搬送されて、熱現像部１８に搬送される。
熱現像部１８は、記録材料Ａを加熱することにより、熱現像を行って潜像を可視像とする部位で、加熱ドラム６８と、エンドレスベルト７０と、剥離爪７２とを有して構成される。
【０１０２】
加熱ドラム６８は、ハロゲンランプ等の加熱用光源やヒータ等の熱源を内蔵するドラムで、その表面が記録材料Ａの熱現像温度に応じた温度に加熱・保持されており、また、軸６８ａを中心に回転してエンドレスベルト７０と共に記録材料Ａを挟持搬送する。
エンドレスベルト７０は、ローラ７４ａ，７４ｂ，７４ｃおよび７４ｄの４つのローラに張架されて、加熱ドラム６８に巻き掛けられるようにして押圧されている。
剥離爪７２は、記録材料Ａを加熱ドラム６８から剥離するものであり、加熱ドラム６８による記録材料Ａの搬送に対応して、加熱ドラム６８に軽く当接、離脱するように構成される。
【０１０３】
搬送ローラ対６６によって熱現像部１８に搬入された記録材料Ａは、エンドレスベルト７０と、ローラ７６および７８とによって挟持搬送されて、加熱ドラム６８とエンドレスベルト７０との間に搬入され、加熱ドラム６８の回転に応じて搬送されつつ、加熱ドラム６８によって熱現像されて、露光によって記録された潜像が可視像となる。
記録材料Ａの先端が剥離爪７２の近傍に搬送されると、剥離爪７２が軽く加熱ドラム６８に当接して、加熱ドラム６８と記録材料Ａとの間に侵入し、記録材料Ａを加熱ドラム６８から剥離する。
【０１０４】
加熱ドラム６８の温度は、一例として、記録材料Ａとして、第１の記録材料Ａを用いる場合には１００℃〜１４０℃、前記第２および第３の記録材料を用いる場合には８５℃〜１５０℃が例示される。
また、記録材料Ａの種類に応じて搬送速度を変更して、あるいは記録材料Ａが完全に収納された後に搬送を停止して、熱現像時間を調整してもよい。なお、熱現像時間は、例えば、第１の記録材料であれば熱現像時間は１０秒〜９０秒、第２および第３の記録材料であれば３秒〜６０秒程度である。
【０１０５】
また、記録材料Ａの熱現像を行うと、熱現像部１８すなわち加熱ドラム６８の表面温度は、記録材料Ａが巻き掛けられた位置（接触したのが記録材料Ａの先端側か後端側か等）や記録材料Ａの比熱等に応じて温度が低下し、温度ムラ、特に搬送方向に温度ムラが生じる。
そのため、本発明の形成装置１０の熱現像部１８は、好ましくは、連続的にプリントを出力する場合であっても、熱現像等によって加熱ドラム６８の表面温度に温度ムラが生じたら、続けて次の記録材料Ａの熱現像を行わずに待機して、加熱ドラム６８の表面温度が全面的に略一定となった後、すなわち、熱現像部１８の温度分布を略一定化（熱分布の初期化）してから熱現像を行う。
従って、この場合には、供給部１２からの記録材料Ａの供給や、露光部１６における潜像の記録は、加熱ドラムの表面温度の略一定化に応じて、タイミングを合わせて行うのが好ましい。
【０１０６】
なお、加熱ドラム６８の表面温度が全面的に略一定になったことの検出は、公知の方法が各種利用可能であり、例えば、温度計等を用いて実際に測定する方法、熱現像の後に表面温度が全面的に略一定化するのに要する時間を実験等によって検知しておき、この熱現像後にこの時間が経過したことをもって略一定化の検出とする方法等が例示される。
【０１０７】
熱現像を終了して、剥離爪７２によって加熱ドラム６８から剥離された記録材料Ａは、装置外に搬送されてトレイ８０に排出される。
ここで、熱現像部１８とトレイ８０との間には、図３に示されるように、光源８２と、光源８２から射出され、記録材料Ａを透過した光の光量を主走査方向の複数点で測定するセンサアレー８４が、記録材料Ａの搬送経路を挟むようにしてが配置されている。
前述のように、記録材料Ａは透明な支持体を用いるフィルムであるので、光源８２から射出されて記録材料Ａを透過した光の光量をセンサアレー８４で計測することにより、記録材料Ａの濃度を測定することができる。
【０１０８】
形成装置１０においては、シェーディング補正データを算出する際に、前述のように、露光部１６においてベタ画像の潜像が形成され、熱現像によって形成されたベタ画像の透過光量がセンサアレー８４で計測される。条件算出部８６は、センサアレー８４で計測された透過光量から画像濃度を算出し、この画像濃度から、各画素のシェーディング補正データを算出する。
【０１０９】
図示例においては、センサアレー８４はセンサ８４ａ〜センサ８４ｅによって主走査方向の５点で記録材料Ａに形成された画像濃度を測定している。主走査方向の測定点は５点に限定はされないが、加熱ドラム６８表面の温度分布は細かい周期では変動しないので、高精細に測定する必要はなく、例えば、形成装置１０が対象とする記録材料Ａの主走査方向の最大サイズが半切サイズの短手方向（３５６mm）であれば、加熱ドラム６８の主走査方向全幅に対して５点〜１０点程度で十分である。
他方、副走査方向の測定間隔にも特に限定はないが、同様に、５点〜１０点程度とすればよい。
なお、最大サイズ以外の記録材料Ａは、各記録材料毎の有効部分のセンサ点数を用いればよい。
また、図示例においては、光源８２は主走査方向に延在する棒状光源を用いているが、本発明はこれに限定はされず、各センサ（測定画素）に対応して配置される点状光源を用いてもよい。なお、図示例のような棒状光源を用いる際には、光源の長手方向の光量ムラを考慮して、画像濃度を算出する必要がある。
【０１１０】
なお、本発明において、熱現像された記録材料Ａの画像濃度の測定方法は、上記方法に限定はされず、公知の濃度測定手段が各種利用可能であり、例えば、記録材料が非透明なものである場合には、反射光を測定することで画像濃度を測定しても良く、あるいは、各種の濃度計を用いて画像濃度を測定してもよい。
【０１１１】
以下、形成装置１０の作用を説明することにより、本発明をより詳細に説明する。
まず、シェーディング補正のためのシェーディング補正データを算出（更新）方法について説明する。
シェーディング補正データ（以下、補正データとする）を算出する際には、その旨の指示に応じて、記録材料Ａが供給部１２から供給され、幅寄せ部１４でサイドレジストを取られて、露光部１６に搬送される。
なお、補正データの算出は、形成装置１０が対象とする最大サイズの記録材料Ａを用いて行い、全サイズの記録材料でこの補正データを用いてシェーディング補正を行ってもよいが、好ましくは、各サイズの記録材料毎に補正データを算出し、対応する補正データを用いてシェーディング補正を行う。
【０１１２】
露光部１６に搬送された記録材料Ａは、副走査搬送手段４８によって副走査搬送されつつ、露光ユニット４６から射出され、主走査方向に偏向された光ビームＬによって２次元的に走査露光され、潜像が記録される。
ここで、補正データを算出（更新）する際には、露光ユニット４６による露光は、記録材料Ａに全面的に一様濃度の画像、すなわちベタ画像を形成するように行われる（露光制御部５２が光源５０を駆動する）。この際のベタ画像の濃度には特に限定はないが、濃度Ｄで１〜１．５程度が好ましい。
なお、補正データを算出するための際のベタ画像の記録では、シェーディング補正は行わずに潜像の記録が行われる。
【０１１３】
露光部１６においてベタ画像の潜像を記録された記録材料Ａは、搬送ローラ対６４，６６等によって熱現像部１８に搬送され、加熱ドラム６８とエンドレスベルト７０と間に挿入されて挟持搬送されつつ熱現像され、潜像が可視像となってベタ画像が形成され、剥離爪７２によって加熱ドラム６８から剥離されて、トレイ８０に搬送される。
ここで、補正データを算出する際には、前述のように、光源８２から射出され、記録材料Ａを透過した光量がラインセンサ８４で測定され、条件算出部８６に送られる。
なお、より高精度なシェーディング補正が可能な補正データを得るためには、この熱現像は、加熱ドラム６８の表面温度分布を全面的に略一定とした後に行うのが好ましい。
【０１１４】
条件算出部８６は、ラインセンサ８４の各センサ８４ａ〜８４ｄによる光量測定結果から、測定点（画素）の各濃度を算出し、測定点の濃度を直線補間等の公知の方法で補間して、記録材料Ａに記録される全画素の補正データを算出する。あるいは、測定点の補正データを算出した後に、これを補間して全画素の補正データを算出してもよい。
なお、本発明においては、全画素の補正データを算出して条件算出部８６に記憶しておいてもよく、あるいは、測定点の補正データ（濃度）のみを条件算出部８６に記憶しておき、露光部１６による潜像の記録時に全画素の補正データを算出してもよい。
補正データの算出方法には特に限定はなく、公知のシェーディング補正データの算出方法と同様でよい。例えば、ベタ画像から測定された最低濃度の画素を基準として、画像データに乗算することでベタ画像の濃度を均一にできる補正係数を各画素毎に算出し、この補正係数を補正データとする方法が例示される。
【０１１５】
このような補正データの算出（あるいは、そのためのベタ画像の記録および濃度測定）は、所定枚数の画像形成毎に定期的に行ってもよく、装置の稼動時間あるいは加熱ドラム６８の加熱時間に応じて定期的に行ってもよく、濃度ムラの検出等のオペレータの判断に応じて適宜行ってもよく、あるいは、これらを組み合わせて行ってもよい。
【０１１６】
形成装置１０による画像形成は、以上のようにして設定された（シェーディング）補正データを用いて、基本的に下記の様に行われる。
画像形成開始の指示が出されると、同様に、対応するサイズの記録材料Ａが供給部１２から供給され、幅寄せ部１４でサイドレジストを取られて、露光部１６に搬送される。
【０１１７】
画像データ供給源Ｒからの画像データは、データ処理部８８に送られており、データ処理部８８は、露光部１６への記録材料Ａの搬送にタイミングを合わせて、条件算出部８６から対応する画素の補正データを受け取り、これを用いて、例えば前記補正係数を画像データに乗算することで画像データの補正すなわちシェーディング補正を行い、さらに、画像データに、キャリブレーションによる補正等の所定の画像処理を施して、露光制御装置５２に出力する。
露光制御装置５２は、供給された画像データすなわち記録画像に応じて光源５０を駆動して、画像データに応じて変調された光ビームＬを射出させる。光源５０から射出された光ビームＬは、ポリゴンミラー５４によって主走査方向に偏向され、ｆθレンズ５６で調光されて、立ち下げミラー５８に反射されて、記録位置Ｘに入射する。
【０１１８】
一方、露光部１６に搬送された記録材料Ａは、副走査搬送手段４８によって副走査搬送されつつ、露光ユニット４６から射出された、記録画像に応じて変調され、主走査方向に変更された光ビームＬによって２次元的に走査露光され、潜像が記録される。
【０１１９】
露光部１６において潜像を記録された記録材料Ａは、搬送ローラ対６４，６６等によって熱現像部１８に搬送され、加熱ドラム６８とエンドレスベルト７０と間に挿入されて挟持搬送されつつ熱現像され、潜像が可視像となって画像が形成される。
ここで、熱現像部１８すなわち加熱ドラム６８の温度ムラや熱現像による温度変化、およびそれに起因する温度ムラは、記録材料Ａの画像濃度には依存せず、常に同じパターンである。従って、ベタ画像を記録して、加熱ドラム６８で熱現像して得られた画像から（シェーディング）補正データを算出し、これを用いて画像データをシェーディング補正して露光を行う本発明によれば、加熱ドラム６８の温度ムラに起因する濃度ムラすなわちシェーディングのない高画質な画像を安定して形成することができる。
【０１２０】
なお、より好適にシェーディングを補正した高画質な画像を得るためには、熱現像は、加熱ドラム６８の表面温度分布が全面的に略一定となった後に行うのが好ましい。
【０１２１】
現像を終了した記録材料Ａは、剥離爪７２によって加熱ドラム６８から剥離されて、可視像が形成されたプリント（ハードコピー）としてトレイ８０に搬送される。
【０１２２】
以上、本発明のシェーディング補正方法および画像形成装置について詳細に説明したが、本発明は上記実施例に限定はされず、本発明の要旨を逸脱しない範囲において、各種の改良および変更を行ってもよいのはもちろんである。
例えば、図示例の形成装置１０においては、補正データを算出するための濃度測定手段が内蔵されているが、本発明はこれに限定はされず、同様にしてベタ濃度の画像を形成した記録材料Ａを出力して、この濃度を外部の濃度計を用いて測定して、これを画像形成装置に入力して、画像形成装置が補正データを算出、記憶する構成としてもよい。
【０１２３】
【発明の効果】
以上詳細に説明したように、本発明のシェーディング補正方法および画像形成装置によれば、感光性の熱現像材料を用いる画像形成において、熱現像部の温度ムラに起因する画像濃度ムラ、すなわちシェーディングのない高画質な画像を安定して作成することができる。
【図面の簡単な説明】
【図１】 本発明の画像形成装置の一例の概略図である。
【図２】 図１に示される画像形成装置の画像露光部の概略図である。
【図３】 図１に示される画像形成装置における形成画像の濃度測定を説明するための概念図である。
【符号の説明】
１０ （画像）形成装置
１２ （記録材料）供給部
１４ 幅寄せ部
１６ （画像）露光部
１８ 熱現像部
２０ マガジン
２２，２４ 装填部
２６，２８ 吸盤
３０，３２ 供給ローラ対
３４，３６，４４，６０，６２，６４，６６ 搬送ローラ対
３８，４０，４２ 搬送ガイド
４６ 露光ユニット
４８ 走査搬送手段
５０，８２ 光源
５２ 露光制御装置
５４ ポリゴンミラー
５６ ｆθレンズ
５８ 立ち下げミラー
６８ 加熱ドラム
７０ エンドレスベルト
７２ 剥離爪
７４ａ，７４ｂ，７４ｃ，７４ｄ，７６，７８ ローラ
８０ トレイ
８４ センサアレイ
８４ａ，８４ｂ，８４ｃ，８４ｄ，８４ｅ センサ
８６ （シェーディング補正）条件算出部
８８ データ処理部
Ａ 記録材料[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of shading correction in image formation using a photosensitive thermal development (thermo-coloring) recording material.
[0002]
[Prior art]
Conventionally, images taken by ultrasonic diagnosis, CT diagnosis, MRI diagnosis, X-ray diagnosis and the like are recorded on a silver salt photographic material and made as a hard copy.
However, the silver salt photographic light-sensitive material can obtain a high-quality image, but requires a wet development process such as color development, fixing bleaching, and washing with water, so that the development process takes time and labor. There is a need for maintenance of the (processor), and output of a hard copy by an image forming method that does not require wet development processing is desired.
[0003]
Thermal image recording is known as an image forming method that does not require wet processing.
As is well known, thermal image recording uses a thermal head having a glaze in which heating elements are arranged in one direction (main scanning direction) and presses the glaze against the thermal recording material. While moving relatively in the orthogonal direction, each heating element generates heat in accordance with the recorded image, thereby recording an image on the heat-sensitive recording material.
The image quality of such thermal recording images has been greatly improved in recent years. Recently, in addition to the recording of ultrasonic diagnostic images that have been conventionally used, CT imaging, MRI diagnosis, X-ray diagnosis, etc. Use in applications where high-quality images are required is also under consideration.
However, in terms of recording density and gradation reproducibility, an image formed by exposing a silver salt photographic light-sensitive material with a light beam or the like is advantageous.
[0004]
Image recording using a photosensitive heat-developable recording material has attracted attention as an image forming method that solves such problems.
The photosensitive heat-developable recording material is a recording material that develops color by exposure and heating, or stops color development by exposure and develops color by heating. The photosensitive heat-developable recording material is exposed imagewise by a light beam or the like. By forming a latent image and heating the exposed photosensitive material, the exposed portion or the non-exposed portion can be colored to obtain a hard copy on which the image is recorded.
According to such image recording using the photosensitive heat development recording material, a high-definition high-quality image using light beam scanning exposure or the like can be formed without performing wet development processing.
[0005]
[Problems to be solved by the invention]
By the way, heat development in image formation using such a photosensitive heat development recording material (hereinafter referred to as recording material) is usually performed by heating the recording material using a heater or the like. As a specific example, a drum incorporating a heater such as a halogen lamp and an endless belt driven by a drum that wraps around the drum about 2/3 times are used. An example is a method in which heat development is performed by heating at a predetermined temperature for a predetermined time by inserting and conveying between the belt and discharging from the opposite end.
[0006]
In image formation using such a recording material, one of the causes of image quality deterioration is shading caused by temperature unevenness of heat development.
As described above, thermal development is performed by bringing a recording material into close contact with a heated drum or the like. However, since a heat source such as a heater for heating the drum usually has a heat distribution, the surface temperature of the drum is not limited. It is difficult to make the entire surface completely uniform, and temperature unevenness (temperature distribution), in particular, temperature unevenness occurs in the axial direction of the drum. Also, the heat of heat development is taken away by the recording material, and the surface temperature of the drum is lowered, but this surface temperature reduction is also not uniform across the entire surface, and as a result, temperature unevenness occurs particularly in the conveyance direction of the recording material. End up.
For this reason, the entire surface of the recording material cannot be thermally developed at a uniform temperature, and unevenness in image density, so-called shading, occurs due to the difference in the degree of thermal development, resulting in a reduction in image quality.
[0007]
An object of the present invention is to solve the above-mentioned problems of the prior art, and in image recording using a photosensitive heat development recording material, shading caused by temperature unevenness of heat development is prevented, and there is no density unevenness. An object of the present invention is to provide a shading correction method capable of stably recording a high-quality image and an image forming apparatus using the shading correction method.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention is directed to imagewise exposing a photosensitive heat-developable recording material according to image data to record a latent image, and thermally developing the photosensitive heat-developable recording material on which the latent image is recorded. A shading correction method in image formation using a photosensitive heat-developable recording material, in which a hard copy on which an image is formed is created by heat development by means, and the entire surface of the photosensitive heat-developable recording material is uniformly exposed. The solid latent image is recorded, and the photothermographic recording material on which the solid latent image is recorded is thermally developed by the heat developing means to form a solid image, and the density of the formed solid image is adjusted.Less than the total number of pixelsShading correction data for each pixel is created by measuring at a plurality of measurement points, and at the time of creating a hard copy, the photosensitive heat development recording material is imagewise exposed with image data corrected using the shading correction data, There is provided a shading correction method characterized in that thermal development is performed by the thermal development means.
[0009]
  In the shading correction method of the present invention, the thermal development of the photosensitive heat-developable recording material on which the solid latent image is recorded and the heat development at the time of making the hard copy, the temperature distribution of the heat developing means is made substantially constant. It is preferable to carry out after this.
  The shading correction data is preferably created by interpolating the density at the plurality of measurement points to calculate correction data for all pixels recorded on the photosensitive heat-developable recording material.
  The measurement of the density of the solid image is preferably performed at a plurality of points in the sub-scanning direction orthogonal to the main scanning direction at a plurality of points in the main scanning direction in the latent image recording.
  Further, the shading correction data is created for each size of the photosensitive heat development recording material used for creating the hard copy, and at the time of creating the hard copy, the size of the photosensitive heat development recording material used for creating the hard copy is set. It is preferable to correct the image data using the corresponding shading correction data.
[0010]
  Furthermore, the present invention provides an image exposure unit for imagewise exposing a photosensitive heat-developable recording material in accordance with image data supplied from an image data supply source to record a latent image, and a photosensitive property on which the latent image is recorded. A heat development part for heat developing the heat development recording material, a sensor for measuring the image density of the photosensitive heat development recording material developed in the heat development part, and the entire surface of the photosensitive heat development recording material by the image exposure part. The solid latent image is recorded by uniform exposure, and the image density of the photosensitive thermal development recording material on which the solid latent image thermally developed by the thermal development unit is recorded is measured by the sensor.Less than the total number of pixelsMeasured at a plurality of measurement points and supplied from the image data supply source by a correction data creation unit that creates shading correction data for each pixel from the density measurement result and the shading correction data created by the correction data creation unit There is provided an image forming apparatus comprising data correction means for correcting the image data.
[0011]
  In the image forming apparatus of the present invention, it is preferable that the thermal development unit thermally develops the photosensitive thermal development recording material on which the latent image is recorded after the temperature distribution becomes substantially constant.
  The correction data creation unit creates the shading correction data by interpolating the density at the plurality of measurement points and calculating correction data for all pixels recorded on the photosensitive heat-developable recording material. Is preferred.
  Further, the sensor is configured by a sensor array that measures at a plurality of points in the main scanning direction in the latent image recording, and measures the image density at a plurality of points in the sub-scanning direction orthogonal to the main scanning direction. preferable.
  The correction data creating unit creates the shading correction data for each size of the photosensitive heat-developable recording material used for creating the hard copy, and the data correcting unit uses the photosensitive heat development data used for creating the hard copy. The image data is preferably corrected using the shading correction data corresponding to the size of the development recording material.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, a shading correction method and an image forming apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
[0013]
FIG. 1 shows a schematic diagram of an example of an image forming apparatus of the present invention that implements the shading correction method of the present invention.
An image forming apparatus 10 (hereinafter, referred to as a forming apparatus 10) shown in FIG. 1 creates a print that reproduces an image measured by a medical measuring instrument such as CT or MRI as a visible image. A device that is suitably used as a major, and uses a photosensitive heat-developable recording material A (hereinafter referred to as recording material A) in which a photosensitive heat-developable image forming layer is formed on a support such as a PET film. The recording material A is imagewise exposed with a light beam L modulated according to image data supplied from an image data supply source R such as MRI, and a latent image is recorded, and then the exposed recording material A is heated. It is developed and colored to output a hard copy on which an image is formed.
[0014]
As the recording material A used in the present invention, various types of heat-developable (thermo-coloring) type recording materials capable of image recording by exposure can be used. Examples of suitable recording materials include the following. .
First, a recording material (hereinafter referred to as a first recording material) having an image forming layer containing 50% or more of a latex made of latex and containing an organic silver salt and an organic silver salt reducing agent on one surface of the support. Is exemplified).
When this first recording material is exposed to light, a photocatalyst such as photosensitive silver halide forms a latent image nucleus, and when heated, the silver of the organic silver salt ionized by the action of the reducing agent is formed. It moves and combines with the photosensitive silver halide to form crystalline silver and form an image.
[0015]
The organic silver salt contained in the image forming layer of the first recording material is relatively stable to light, but in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent. The silver salt that forms a silver image when heated to 80 ° C. or higher, and may be desalted as necessary.
Such an organic silver salt includes a silver salt of an organic acid, preferably a silver salt of a long-chain fatty carboxylic acid having 10 to 30 carbon atoms, and a complex stability constant having a ligand of 4.0 to 10.0. Examples of the organic or inorganic silver salt complex include, specifically, silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, malein Examples include silver oxide, silver fumarate, silver tartrate, silver linoleate, silver butyrate, and silver camphorate.
[0016]
Further, as the organic silver salt, a silver salt of a compound containing a mercapto group or a thione group and derivatives thereof can be suitably used. Specifically, 3-mercapto-4-phenyl-1,2,4- Silver salt of triazole, silver salt of 2-mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, silver salt of thioglycolic acid such as silver salt of S-alkylthioglycolic acid, silver salt of dithioacetic acid, etc. Examples include silver salts of dithiocarboxylic acids, silver salts of thioamides, silver salts of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salts of mercaptotriazine, and silver salts of 2-mercaptobenzoxazole. .
[0017]
The shape of the organic silver salt is preferably an acicular crystal having a short axis and a long axis, and more specifically, a short axis of 0.01 μm to 0.2 μm and a long axis of 0.1 μm to 5 μm are more preferable.
Further, the organic silver salt is preferably monodispersed. Specifically, the 100-percentage of the value obtained by dividing the standard deviation of the lengths of the minor axis and the major axis by the minor axis and the major axis is 100% or less. Is preferred.
[0018]
For the purpose of obtaining fine particles having a small particle size and no aggregation, such an organic silver salt is made into a solid fine particle dispersion by using a known dispersant such as polyacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone and the like. preferable.
The dispersion of the organic silver salt into solid fine particles may be carried out by a known mechanical fine particle dispersion method using a ball mill, a vibration ball mill or the like in the presence of a dispersant.
In addition to the mechanical dispersion method, it may be coarsely dispersed in a solvent by controlling the pH, and then finely divided by changing the pH in the presence of a dispersion aid.
[0019]
The amount of the organic silver salt is preferably 0.1 g / l to 5 g / l, more preferably 1 g / l to 3 g / l as the amount of silver.
[0020]
As the reducing agent for reducing the organic silver salt, any substance capable of reducing silver ions to metallic silver can be used, and preferably an organic substance, such as Japanese Patent Application Nos. 57-82829 and 6-3793. Various known reducing agents used for photosensitive and thermosensitive recording materials using organic silver salts disclosed in the above publications, US Pat. No. 5,464,738, etc. can be used.
Specifically, an amide oxime such as phenylamidoxime; an azine such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; a hydroxamic acid such as phenylhydroxamic acid; an α such as ethyl-α-cyano-2-methylphenylacetate A cyanophenylacetic acid derivative; a bis-β-naphthol such as 2,2′-dihydroxy-1,1′-binaphthyl; a 5-pyrazolone such as 3-methyl-1-phenyl-5-pyrazolone; a dimethylaminohexose reductone Reductones such as; sulfonamidophenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol; chromanes such as 2,2-dimethyl-7-tert-butyl-6-hydroxychroman; 2,6-dimethoxy- 3,5-dicarboethoxy-1,4 1,4-dihydropyridine such as dihydropyridine; bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene -Bis (2-tert-butyl-6-methylphenol), 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane, 2,2-bis (3 Bisphenols such as 5-dimethyl-4-hydroxyphenyl) propane; ascorbic acid derivatives such as 1-ascorbyl palmitate; chromanols such as tocopherol and the like, and bisphenol and chromanol are particularly preferably used.
In addition, known photographic developers such as phenidone, hydroquinone, and catechol are also preferably used, and hindered phenol reducing agents are particularly preferable.
[0021]
What is necessary is just to add a reducing agent by methods, such as a solution, a powder, and a solid fine particle dispersion. The solid fine particle dispersion is performed by a known finer means (ball mill, vibrating ball mill, etc.). A dispersion aid may be used when dispersing the solid fine particles.
The amount of the reducing agent is preferably about 5 mol% to 50 mol% with respect to 1 mol of silver on the surface having the image forming layer. The reducing agent is basically added to the image forming layer, but may be other layers on the side having the image forming layer, and in this case, 10 mol% to 50 mol% per 1 mol of silver should be used in a large amount. Is preferred. The reducing agent may be a so-called precursor that is derivatized so as to have a function effectively only during development.
[0022]
The image forming layer of the first recording material contains a substance that is exposed to light and becomes a photocatalyst, for example, photosensitive silver halide (hereinafter referred to as silver halide).
The halogen composition of silver halide is not limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. And silver iodobromide are preferably used.
The grain size of silver halide is preferably 0.20 μm or less in order to suppress white turbidity after image formation, and cubic grains and tabular grains are particularly preferred.
[0023]
The silver halide grains preferably contain at least one metal complex selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt, mercury or iron, and about 1 nmol to 10 mmol per 1 mol of silver. These metal complexes are described in detail in JP-A-7-22549.
In addition, the containing phase of the metal complex in the silver halide may be uniform or may be contained in the core part or the shell part at a high concentration, and there is no particular limitation.
[0024]
The silver halide grains are preferably chemically sensitized.
There are no particular limitations on the method of chemical sensitization. For example, sulfur sensitization, selenium sensitization, tellurium sensitization using diacyl tellurides and bis (oxycarbonyl) tellurides, chloroauric acid and potassium, etc. Examples include noble metal sensitization using chloroaurate and the like, reduction sensitization using ascorbic acid, thiourea dioxide, etc., sulfur sensitization, selenium sensitization, tellurium sensitization and the like.
Reduction sensitization by a method of ripening while maintaining the pH of the emulsion at 7 or higher or pAg of 8.3 or lower, or a method of introducing a single addition portion of silver ions during grain formation can also be used.
[0025]
The amount of silver halide used is preferably 0.01 mol to 0.5 mol with respect to 1 mol of the organic silver salt.
Regarding the mixing method and mixing conditions when silver halide and organic silver salt are prepared separately, the silver halide particles and organic silver salt that have been prepared are respectively mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill. Examples thereof include a method of mixing with a homogenizer or the like, or a method of preparing an organic silver salt by mixing silver halides that have been prepared at any timing during the preparation of the organic silver salt.
In addition, as a method for adjusting the silver halide and mixing with the organic silver salt, a so-called hydration method in which a part of the silver of the organic silver salt is halogenated with an organic or inorganic halide is also preferably used. Examples of the organic halide used herein include N-halogenoimides such as N-bromosuccinimide, and halogenated quaternary nitrogen compounds such as tetrabutylammonium bromide. Examples of inorganic halogen compounds include lithium bromide and potassium iodide. Examples include alkali metal halides, ammonium halides such as ammonium bromide, alkaline earth metal halides such as calcium bromide, and halogen molecules such as bromine and iodine. In addition, the addition amount of the halide at the time of halation is preferably 1 mmol to 500 mmol as a halogen atom per 1 mol of the organic silver salt.
[0026]
In the first recording material, the image forming layer having such a composition contains at least 50 wt% of a latex in which a water-insoluble hydrophobic polymer is dispersed as fine particles in a water-soluble dispersion medium. To do. Alternatively, if necessary, other layers may have the same configuration.
The latex is dispersed in a state in which the polymer is emulsified in a dispersion medium, emulsion polymerized, micelle-dispersed, or partially hydrophilic in the polymer molecule and the molecular chain itself is a molecule. Any of these may be used. The latex may be a so-called core / shell type latex in addition to a normal uniform latex.
For such latexes, see “Synthetic Resin Emulsions (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Publishing (1978))”, “Applications of Synthetic Latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara, Polymer) Publication of publication (1993)), “Synthetic latex chemistry (Muroichi Muroi, published by Polymer publication (1970))” and the like.
[0027]
Examples of such latex polymers include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, and polyolefin resins.
The polymer may be a linear polymer or a branched polymer, and may be crosslinked. The polymer may be a so-called homopolymer in which a single monomer is polymerized or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer.
The molecular weight of the polymer is 5,000 to 1,000,000, preferably about 10,000 to 100,000 in terms of number average molecular weight. When the molecular weight is too small, the mechanical strength of the photosensitive layer is insufficient.
[0028]
Specific examples of such polymers include methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, styrene / butadiene / acrylic acid copolymer, styrene / butadiene / divinylbenzene / methacrylic. Examples include acid copolymers, methyl methacrylate / vinyl chloride / acrylic acid copolymers, vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymers, and the like.
Various commercially available products can also be used as the polymer. For example, Ceviane A-4635 manufactured by Daicel Chemical Industries, Ltd. as an acrylic resin, FINETEX ES650 manufactured by Dainippon Ink Chemical Co., Ltd. as a polyester resin, and HYDRAN AP10 manufactured by Dainippon Ink Chemical Co., Ltd. as a polyurethane resin. For example, LACSTAR 7310K manufactured by Dainippon Ink Chemical Co., Ltd. as rubber-based resin, G351 manufactured by Nippon Zeon Co., Ltd. as vinyl chloride resin, L502 manufactured by Asahi Kasei Kogyo Co., Ltd. as polyolefin resin, polyolefin resin Examples thereof include Chemipearl S124 manufactured by Mitsui Petrochemical Co., Ltd.
These polymers may be used alone or in combination of two or more as required.
[0029]
The average particle diameter of the dispersed particles in the latex is preferably in the range of 1 nm to 50000 nm, more preferably about 5 nm to 1000 nm. The particle size distribution of the dispersed particles is not particularly limited, and may be a product having a wide particle size distribution or a monodispersed particle size distribution.
The minimum film forming temperature (MFT) of the latex is preferably −30 ° C. to 90 ° C., more preferably 0 ° C. to 70 ° C.
[0030]
As described above, in the image forming layer of the first recording material, it is preferable that 50 wt% or more of the total binder is latex, and particularly 70 wt% or more is latex.
In addition, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, or hydroxypropyl methylcellulose may be added to the image forming layer as necessary within a range of 50 wt% or less of the total binder. good. The amount of these hydrophilic polymers added is preferably 30 wt% or less of the total binder in the photosensitive layer.
Furthermore, it is preferable that the latex dispersed particles (polymer) have an equilibrium water content of 2 wt% or less, more preferably 1 wt% or less at 25 ° C. and 60% RH.
[0031]
In the image forming layer of the first recording material or another layer on the same side as the image forming layer, an additive known as a toning agent is preferably used for the purpose of improving the optical density, preferably 0.1 mol% to 1 mol% per 1 mol of silver. About 50 mol% may be contained. The toning agent may be a precursor derivatized so as to have an effective function only during development.
As the color toning agent, various known materials used for photosensitive and thermosensitive recording materials can be used. Specifically, phthalimide compounds such as phthalimide; cyclic imides such as succinimide; N-hydroxy-1,8-naphthalimide Naphthalimides such as cobalt complexes such as cobalt hexamine trifluoroacetate; mercaptans such as 3-mercapto-1,2,4-triazole; phthalazinone derivatives such as 4- (1-naphthyl) phthalazinone and metal salts thereof The solution is added to the coating solution as a solution, powder, solid fine particle dispersion or the like.
[0032]
In the first recording material having such an image forming layer, if necessary, a sensitizing dye is added to the image recording layer and / or other layers, preferably 10 mol / mol of silver halide in the image forming layer.^-6You may contain about mol-1mol.
Any sensitizing dye can be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. For example, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex Merocyanine dyes, holophoran cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes, and the like can be used, and a sensitizing dye having spectral sensitivity suitable for the spectral characteristics of the recording light L may be selected.
In order to add a sensitizing dye into a silver halide emulsion, they may be dispersed directly in the emulsion, or dissolved in water, methanol, ethanol, N, N-dimethylformamide alone or in a mixed solvent. May be added to the emulsion.
[0033]
The image recording layer and / or other layer of the first recording material contains an antifoggant, a stabilizer, a stabilizer precursor, and the like for the purpose of preventing additional fogging and a decrease in sensitivity during storage. Also good.
Antifoggants, stabilizers and stabilizer precursors include thiazonium salts described in US Pat. No. 2,131,038 and the like, azaindenes described in US Pat. No. 2,886,437 and the like, Examples include mercury salts described in Japanese Patent No. 2,728,663 and urazole described in US Pat. No. 3,287,135. As the antifoggant, organic halides disclosed in JP-A-50-119624, JP-A-8-15809 and the like are also preferably used.
The antifoggant and the like may be added to the coating solution as a solution, powder, solid fine particle dispersion or the like.
[0034]
The image recording layer and / or other layers of the first recording material may contain benzoic acids for the purpose of increasing sensitivity and preventing fogging.
As benzoic acids, various benzoic acid derivatives can be used. Preferred examples include compounds described in the specifications of US Pat. No. 4,787,939 and Japanese Patent Application No. 8-151242. It is added to the liquid as a powder, solution, or fine particle dispersion.
The amount of benzoic acid added may be any amount, but is preferably about 1 μmol to 2 mol per mol of silver.
[0035]
In the image recording layer and / or other layers of the first recording material, mercapto compounds, silsulfide compounds, thiones are used for the purpose of suppressing or promoting development, improving spectral sensitization efficiency, and improving storage stability before and after development. A compound may be contained.
When a mercapto compound is used, it may have any structure, but those represented by Ar-SM and Ar-SS-Ar are preferred (wherein M is a hydrogen atom or an alkali metal atom, Ar is An aromatic ring or condensed aromatic ring having at least one of nitrogen, sulfur, oxygen, selenium and tellurium). Specifically, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole and the like are exemplified.
The amount of mercapto compound added is preferably about 0.001 mol to 1 mol per mol of silver.
[0036]
The image recording layer and / or other layer of the first recording material may contain various dyes and pigments for the purpose of improving the color tone and preventing irradiation.
Any dyes and pigments may be used. For example, there are pigments and dyes described in the color index. Specifically, pyrazoloazole dyes, anthraquinone dyes, azo dyes, azomethine dyes, oxonol dyes, carbocyanine dyes, styryl dyes, Examples include organic pigments such as phenylmethane dyes, indoaniline dyes, indophenol dyes, phthalocyanines, and inorganic pigments, and are added to the coating liquid as a solution, emulsion, solid fine particle dispersion, or mordanted with a polymer mordant. The
The amount of these compounds to be used is determined by the target absorption amount, but is generally about 1 μg to 1 g per liter.
[0037]
Further, in addition to these components, the image recording layer and / or other layers of the first recording material include plasticizers and lubricants (for example, the type described in US Pat. No. 2,960,404). Glycerin and diol), ultra-high contrast agent (for example, hydrazine derivatives described in Japanese Patent Application No. 8-148116), and high-acceleration accelerator (for example, onium salts described in Japanese Patent Application No. 8-132936) Further, it may contain a hardening agent (for example, polyisocyanates described in JP-A-6-208193).
[0038]
The first recording material may have various layers in addition to the image forming layer.
For example, a protective layer can be provided for the purpose of protecting the image forming layer or preventing adhesion. The protective layer is formed of an anti-adhesion material, and for example, wax, silica particles, styrene-containing elastomeric block copolymers (styrene-butadiene-styrene, etc.), cellulose acetate, cellulose acetate butyrate, cellulose propionate, etc. are used. .
[0039]
An antihalation layer may be provided.
The antihalation layer preferably has a maximum absorption in the desired wavelength range of 0.3 to 2 and an absorption in the visible region after treatment of 0.001 to 0.5.
When an antihalation dye is used, this dye may be any compound as long as it has the desired absorption in the wavelength range, has a sufficiently low absorption in the visible region after processing, and can obtain the preferred absorbance spectrum shape of the antihalation layer. For example, the following is disclosed, but the present invention is not limited to this. Examples of the single dye include compounds disclosed in JP-A Nos. 7-11432 and 7-13295, and examples of dyes that can be erased by treatment include JP-A-52-139136 and JP-A-7-7-1. Examples thereof include compounds disclosed in each publication of No. 199409.
[0040]
The first recording material preferably has an image forming layer on one side of the support and a back (coat) layer on the other side.
A matting agent may be added to the back layer to improve transportability. The matting agent is generally fine particles of an organic or inorganic compound that is insoluble in water. As the organic compound, polymethyl acrylate, methyl cellulose, carboxy starch, carboxynitrophenyl starch and the like are preferably exemplified as examples of the water-dispersible vinyl polymer, and as the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, Barium sulfate and the like are preferably exemplified
The size and shape of the matting agent are not particularly limited, but it is preferable to use a matting agent having a particle size of 0.1 μm to 30 μm. Also. As the back layer mat degree, the Beck smoothness is preferably 250 seconds to 10 seconds.
[0041]
As the binder for forming the back layer, various resins that are preferably colorless and transparent or translucent can be used. For example, gelatin, gum arabic, polyvinyl alcohol, hydroxyethyl cellulose, cellulose acetate, cellulose acetate petite, Casein, starch, poly (meth) acrylic acid, polymethylmethacrylic acid, polyvinyl chloride and the like are exemplified.
The back layer preferably has a maximum absorption in a desired wavelength range of 0.3 to 2, and an antihalation dye used in the antihalation layer may be added as necessary.
[0042]
Further, the back layer side surface has a backside resistive heating layer disclosed in each specification such as US Pat. Nos. 4,460,681 and 4,374,921. May be.
[0043]
In addition to these layers, the first recording material includes an antistatic or conductive layer using a soluble salt (for example, chloride, nitrate, etc.), a deposited metal layer, US Pat. No. 2,861,056, A layer containing an ionic polymer disclosed in US Pat. No. 3,428,451, a layer containing an insoluble inorganic salt disclosed in US Pat. No. 3,428,451, and the like.
[0044]
As another example of the suitable recording material A used in the present invention, the following are further exemplified.
In this recording material (hereinafter referred to as a second recording material), the image forming layer has an electron donating colorless dye encapsulated in the thermoresponsive microcapsule and the same molecule in addition to the thermoresponsive microcapsule. A recording material comprising a compound having an electron accepting portion and a polymerizable vinyl monomer portion, and a photopolymerization initiator.
[0045]
In addition, as another recording material (hereinafter referred to as a third recording material), the image forming layer includes an electron-donating colorless dye encapsulated in a thermoresponsive microcapsule and a thermoresponsive microcapsule. A recording material containing an electron accepting compound, a polymerizable vinyl monomer, and a photopolymerization initiator is also exemplified.
[0046]
These second and third recording materials are fixed by curing the composition outside the heat-responsive microcapsule (hereinafter referred to as a photocurable composition) by exposure, and moving by heating. A non-immobilized compound having an electron accepting part and a polymerizable vinyl monomer part or an electron accepting compound moves in the image forming layer to give an electron-donating colorless dye in the microcapsule Is a recording material for forming an image by coloring.
Both recording materials are described in detail in Japanese Patent Application No. 8-333724 by the applicant.
[0047]
The compound having an electron accepting part and a polymerizable vinyl monomer part in the same molecule, which is used in the photocurable composition of the second recording material, contains an electron accepting group and a vinyl group in one molecule. A compound.
Specifically, styrenesulfonylaminosalicylic acid, vinylbenzyloxyphthalic acid, β- (meth) acryloxyethoxysalicylic acid zinc, vinyloxyethyloxybenzoic acid, β- (meth) acryloxyethylorcerinate, β- ( (Meth) acryloxyethoxyphenol, β- (meth) acryloxyethyl-β-resorcinate, hydroxystyrene sulfonic acid-N-ethylamide, β- (meth) acryloxyprovir-p-hydroxybenzoate, (meth) acryloxymethyl Phenol, (meth) acrylamidopropanesulfonic acid, β- (meth) acryloxyethoxy-dihydroxybenzene, γ-styrenesulfonyloxy-β- (meth) acryloxypropanecarboxylic acid, γ- (meth) acryloxypropyl-α- Hydroxyethyl Ruoxysalicylic acid, β-hydroxyethoxycarbonylphenol, 3,5-distyrenesulfonic acid amide phenol, (meth) acryloxyethoxyphthalic acid, (meth) acrylic acid, (meth) acryloxyethoxyhydroxynaphthoic acid, β- ( Preferred are (meth) acryloxyethyl-p-hydroxybenzoate, β '-(meth) acryloxyethyl-β-resorcinate, β- (meth) acryloxyethyloxycarbonylhydroxybenzoic acid, etc., and metal salts thereof such as zinc salts. Can be used.
[0048]
The above compound can also be suitably used as a polymerizable vinyl monomer of the photocurable composition of the third recording material.
Further, as the polymerizable vinyl monomer used in the third recording material, various other monomers having at least one vinyl group in the molecule can be used. For example, (meth) acrylic acid and its monomer Salts, (meth) acrylic acid esters, (meth) acrylamides; maleic anhydride, maleic acid esters; itaconic acid, itaconic acid esters; styrenes; vinyl ethers and esters; N-vinyl heterocycles; And esters can be used.
In particular, monomers having a plurality of vinyl groups in the molecule are preferable. For example, (meth) acrylic acid esters of polyhydric alcohols, polyhydric phenols, (meth) acrylic acid esters of bisphenols, (meth) acrylate-terminated epoxies Resins, (meth) acrylate terminated polyesters. Specific examples include ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hydroxypentaacrylate, hexanediol-1,5-dimethacrylate, and diethylene glycol dimethacrylate. The
These monomers preferably have a molecular weight of about 100 to about 5000.
[0049]
The photopolymerization initiator used for the second and third recording materials is a compound capable of initiating photopolymerization of the vinyl monomer, preferably when used in combination with green, red to infrared absorbing dyes. An organic borate salt compound, more preferably an organic borate salt of a cationic dye, which is sensitive to a wavelength region and generates a radical upon irradiation with light (see JP-A-62-143044).
The organic borate salt generates a radical in response to the irradiated laser beam, and this radical initiates polymerization of the vinyl monomer part.
[0050]
As the organic borate salt, a compound represented by the following general formula (1) is used.
[Chemical 1]

[0051]
In the general formula (1), M is an alkali metal atom, quaternary ammonium, pyridinium, quinolinium, diazonium, morpholinium, tetrazolium, acridinium, phosphonium, sulfonium, oxosulfonium, sulfur, oxygen, carbon, halogenium, Cu, Ag , A cation selected from Hg, Pd, Fe, Co, Sn, Mo, Cr, Ni, As, and Se, n is an integer of 1 to 6,¹, R², R^ThreeAnd R^FourAre each a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, an alicyclic group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkaryl group. Represents a substituted or unsubstituted aryloxyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted heterocyclic group, or a substituted or unsubstituted silyl group. Where R¹, R², R^ThreeAnd R^FourMay be the same as or different from each other, and two or more of them may be bonded to form a cyclic structure.
[0052]
In the above general formula (1), the borate anion includes tetraethyl borate, triisobutyl methyl borate, di-n-butyl-di-t-butyl borate, tetraphenyl borate, tetra-p-chlorophenyl borate, tri-m-chlorophenyl. -N-hexyl borate, triphenyl ethyl borate, trimethyl butyl borate, tolyl isopropyl borate, triphenyl benzyl borate, tetraphenyl borate, tetrabenzyl borate, triphenylphenethyl borate, triphenyl-p-chlorobenzyl borate, triphenyletheni Tubuluboleate, di (α-nephtyl) -dipropylborate, triphenylsilyltriphenylborate, tritoluylsilylphenylborate, tri-n-butyl (dimethyl) Phenyl silyl) borate and the like.
[0053]
Below, an example of the organic borate salt shown by General formula (1) is shown.
[Chemical formula 2]

[0054]
In order to increase the light absorption efficiency of the recording light L or the like, the organic borate salt represented by the general formula (1) is preferably used in combination with a green to red region and an infrared absorbing dye as a spectral sensitizing dye.
In particular, an organic cationic dye having a maximum absorption wavelength in a wavelength region of 500 nm to 1100 nm is preferably used. Specifically, a cationic methine dye, a cationic carbonium dye, a cationic quinoneimine dye, a cationic indoline dye, a cationic substance And styryl dyes. More specifically, examples of the cationic methine dye include polymethine dyes, cyanine dyes, azomethine dyes, more preferably cyanine, carbocyanine, dicarbocyanine, tricarbocyanine, hemicyanine, and the like. , Triarylmethane dyes, xanthene dyes, alicudin dyes, more preferably rhodamine dyes, and the cationic quinoneimine dyes are preferably dyes selected from azine dyes, oxazine dyes, thiazine dyes, quinoline dyes, thiazole dyes, etc. These may be used alone or in combination of two or more.
[0055]
As the photopolymerization initiator, an organic borate salt of a cationic dye represented by the following general formula (2) is more preferably used.
[0056]
[Chemical Formula 3]

[0057]
In the above general formula (2), D⁺Represents a cationic dye, R¹, R², R^ThreeAnd R^FourIs a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted alkenyl group, substituted or unsubstituted Alkynyl group, substituted or unsubstituted aryloxyl group, substituted or unsubstituted alicyclic group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted allyl group, substituted or unsubstituted silyl group, alicyclic group Is a group selected from R¹, R², R^ThreeAnd R^FourMay be the same as or different from each other, and two or more of them may be bonded to form a cyclic structure.
[0058]
In the above general formula (2), D⁺Is an organic cationic dye having an absorption peak in a wavelength region of 500 nm or more, particularly in a wavelength region of 550 nm to 1100 nm.
Specific examples include cationic methine dyes, cationic carbonium dyes, cationic quinoneimine dyes, cationic indoline dyes, and cationic styryl dyes. More specifically, the cationic methine dye is preferably polymethine. Dyes, cyanine dyes, azomethine dyes, more preferably cyanine, carbocyanine, dicarbocyanine, tricarbocyanine, hemicyanine and the like, and as the cationic carbonium dye, preferably triarylmethane dye, xanthene dye, alkidine dye, Rhodamine and the like are preferable, and the cationic quinoneimine dye is preferably a dye selected from azine dyes, oxazine dyes, thiazine dyes, quinoline dyes, thiazole dyes and the like.
Moreover, as a borate anion, the same thing as the said General formula (1) is illustrated suitably.
[0059]
Below, an example of the organic borate salt of the cationic pigment | dye shown by General formula (2) is shown.
[Formula 4]

[0060]
[Chemical formula 5]

[0061]
The content of these photopolymerization initiators is preferably 0.01% by weight to 20% by weight based on the total weight of the photocurable composition (outside the thermoresponsive microcapsule).
[0062]
In this thermochromic recording material, a compound having an active halogen group in the molecule represented by the following general formula (3) or general formula (4), together with the above-mentioned photopolymerization initiator or spectral sensitizing dye, is used as an auxiliary agent. Can be used together.
[0063]
[Chemical 6]

In the general formula (3), X represents a halogen atom, Y¹Is -CX_Three, -NH₂, -NHR, -NR₂, -OR. Here, R represents an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. Y²Is -CX_ThreeRepresents an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, or a substituted alkenyl group. The substituent may be the general formula (3) itself.
[0064]
[Chemical 7]

In the general formula (4), X represents a halogen atom. Y^Three, Y^FourMay be the same or different and each represents a hydrogen atom or a halogen atom. Z represents a group represented by the following formula.
[Chemical 8]

Where R¹Represents a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a substituted alkenyl group, a heterocyclic group, or a substituted heterocyclic group.
[0065]
Moreover, as a compound represented by General formula (3), Y¹Is CX_ThreeIs preferably used.
Specifically, the compound represented by the general formula (3) includes 2-phenyl-4,6-bis (trichloromethyl) -S-triazine, 2- (p-chlorophenyl) -4,6- Bis (trichloromethyl) -S-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -S-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2 Preferred examples include-(p-cyanophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (p-acetylphenyl) -4,6-bis (trichloromethyl) -S-triazine and the like. The
[0066]
On the other hand, the compound represented by the general formula (4) includes carbon tetrachloride, carbon tetrabromide, iodoform, p-nitro-α, α, α-tripromoacetophenone, ω, ω, ω-tripromokinal. Examples thereof include gin, tripromomethyl phenyl sulfone, and trichloromethyl phenyl sulfone.
[0067]
The compound represented by the general formula (3) or (4) is used in an amount of 0.01 mol to 1 mol of the compound represented by the general formula (3) or (4) with respect to 1 mol of the spectral sensitizing dye (cationic dye). It is preferable to add 20 mol.
[0068]
The second and third recording materials are highly sensitive and sensitive to infrared light, but as auxiliary agents for promoting latent image formation, reducing agents such as oxygen scavenger and active hydrogen Donor chain transfer agents and other compounds may be used in combination.
Oxygen scavengers that have been found to be useful as an aid to promote latent image formation are phosphines, phosphonates, phosphites, stannous salts and other compounds that are readily oxidized by oxygen, For example, N-phenylglucin, trimethylbarbituric acid, N, N-dimethyl-2,6-diisopropylaniline and the like are exemplified.
[0069]
An electron-accepting compound is added to the photocurable composition of the third recording material. Further, if necessary, an electron accepting compound may be added to the photocurable composition of the second recording material, thereby improving the color density.
Examples of the electron-accepting compound include phenol derivatives, salicylic acid derivatives, metal salts of aromatic carboxylic acids, acidic clay, bentonite, novolac resins, metal-treated novolac resins, metal complexes, and the like. Examples of phenol derivatives include 2,2'-bis (4-hydroxyphenyl) propane, 4-t-butylphenol, 4-phenylphenol, 4-hydroxydipheninoxide, 1,1'-bis (3-chloro Examples include -4-hydroxyphenyl) cyclohexane and 1,1'-bis (3-chloro-4-hydroxyphenyl) -2-ethylbutane. Examples of salicylic acid derivatives include 4-pentadecylsalicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (tert-octyl) salicylic acid, 5-octadecylsalicylic acid, 5-α- (p- Examples include α-methylbenzylphenyl) ethylsalicylic acid, 3-α-methylbenzyl-5-tert-octylsalicylic acid, 5-tetradecylsalicylic acid and the like.
These electron-accepting compounds are preferably used in an amount of about 5 to 1000% by weight of the electron-donating colorless dye.
[0070]
Such photocurable compositions of the second and third recording materials include, in addition to these compounds, as photocrosslinkable compositions, for example, polycinnamate, polycinnamylidene vinyl acetate, α-phenylmaleimide You may add the photocurable composition etc. which have group. Moreover, you may use these photocrosslinkable compositions as a photocurable component.
[0071]
Furthermore, in addition to these compounds, the photocurable composition has the purpose of preventing the thermal and temporal polymerization of the photocurable composition and improving the stability as necessary. A thermal polymerization inhibitor may be added.
Examples of thermal polymerization inhibitors include p-methoxyphenol, hydroquinone, t-butylcatechol, pyrogallol, 2-hydroxybenzophenone, 4-methoxy-2-hydroxybenzophenone, cuprous chloride, phenothiazine, chloranil, naphthylamine, β-naphthol, 2,6-di-t-butyl-p-cresol, nitrobenzene, dinitrobenzene, picric acid, p-toluidine and the like are preferably exemplified, and 0.001% to 5% by weight based on the total weight of the photocurable composition It is preferable to add about%.
[0072]
The photocurable composition is emulsified and dispersed and contained in the image forming layer.
Solvents used for emulsifying and dispersing the photocurable composition include cottonseed oil, kerosene, aliphatic ketone, aliphatic ester, paraffin, naphthenic oil, alkylated biphenyl, chlorinated paraffin, 1,1′-ditolylethane, and the like. Diarylethane, alkyl esters of phthalates such as dibutyl phthalate, phosphates such as diphenyl phosphate, citrates such as tributyl acetylcitrate, benzoates such as octyl benzoate, alkyl amides such as diethyl lauryl amide, ethyl acetate, etc. Examples include acetic acid esters, (meth) acrylic acid esters such as methyl (meth) acrylate, alkyl halides such as methylene chloride and carbon tetrachloride, methyl isobutyl ketone, β-ethoxyethyl acetate, and methyl cellosolve acetate. In particular, aliphatic esters and alkyl halides are preferable, and those having a solubility in water of 10% by volume or less are more preferable.
These solvents are preferably used in a proportion of 1 part by weight to 500 parts by weight with respect to the photopolymerizable compound.
[0073]
The water-soluble polymer that can be used for emulsifying and dispersing the photocurable composition is preferably a compound that dissolves 5% by weight or more in water at 25 ° C., specifically, gelatin, gelatin derivatives, albumin Protein, cellulose derivatives such as methylcellulose, sugar derivatives such as starches (including modified starch), polyvinyl alcohol, styrene-maleic anhydride copolymer hydrolyzate, carboxy modified polyvinyl alcohol, polyacrylamide, vinyl acetate-poly Examples include saponified products of acrylic acid copolymers and synthetic polymers of polystyrene sulfonate sugars, and gelatin and polyvinyl alcohol are particularly preferable.
[0074]
On the other hand, electron-donating colorless dyes encapsulated in the microcapsules of the image-forming layers of the second and third recording materials are conventionally known triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, Various compounds such as an indolylphthalide compound, a leucooramine compound, a rhodamine lactam compound, a totaphenylmethane compound, a triazene compound, a spiropyran compound, and a fluorene compound can be used.
Specifically, the triphenylmethane phthalide compounds include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide and 3- (p-dimethylaminophenyl) -3- (2-methyl). Indol-3-yl) phthalide; N-halophenyl-leucooramine and N-2,4,5-trichlorophenylleucooramine as leucooramine compounds; rhodamine-B as rhodamine lactam compound -Anilinolactam, rhodamine- (p-nitrino) lactam and the like: Examples of the fluorane compound include 2- (dibenzylamino) fluorane, 2-anilino-3-methyl-6-diethylaminofluorane and 2-anilino-3- Methyl-6-N-methyl-N-cyclohexylaminofluorane and the like; phenothiazine Benzoyl Roy Con methylene blue or p- nitrobenzyl leuco methylene blue, etc. As the compound. Examples of the spiropyran compound 3-methyl - spiro - dinaphthopyran and 3,3'-dichloro - spiro - dinaphthopyran etc.; are respectively illustrated.
[0075]
Microcapsules encapsulating such an electron-donating colorless dye can be obtained using methods known in the art.
For example, a method utilizing coacervation of a hydrophilic wall forming material disclosed in US Pat. No. 2,800,457, an interfacial polymerization method disclosed in JP-B-42-771, US Pat. No. 3,660,304, a method by precipitation of a polymer, a method using an isocyanate polyol wall material disclosed in US Pat. No. 3,796,669, US Pat. No. 3,914,511 A method using an isocyanate wall material disclosed in US Pat. No. 4,089,802 and a method using a urea formaldehyde-resorcinol wall forming material disclosed in US Pat. No. 4,089,802 are disclosed. In particular, it is preferable to form a polymer film as a microcapsule wall after emulsifying the core substance.
[0076]
Among them, the microencapsulation method by polymerization of a reactant from the inside of oil droplets is particularly preferable in that a recording material having a uniform particle diameter and excellent storage stability can be obtained within a short time.
For example, when polyurethane is used as a capsule wall material, a polyvalent isocyanate and a second substance that reacts with it to form a capsule wall (eg, polyol, polyamine) are mixed in an oily liquid to be encapsulated and emulsified in water. By dispersing and then raising the temperature, a polymer forming reaction is caused at the oil droplet interface to form a microcapsule wall. At this time, an auxiliary solvent having a low boiling point and a strong dissolving power can be used in the oily liquid.
[0077]
The polyvalent isocyanate used in this case is m-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, diphenylmethane-4,4-diisocyanate, xylylene-1,4-diisocyanate, 4,4. Various polyvalent isocyanates used for the production of known urethane resins such as' -diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate and the like can be used. The polyvalent isocyanate can also react with water to form a polymer material.
Examples of the polyol include aliphatic and aromatic polyhydric alcohols, hydroxy polyesters, hydroxy polyalkylene ethers, and the like. Specifically, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, propylene glycol, 2,3-dihydroxybutane, 1,2-dihydroxybutane, 2,5-hexanediol, 3-methyl-1,5-pentanediol, dihydroxycyclohexane, etc. Various polyols used in the production of known urethane resins can be used. The polyol is preferably used in a ratio of hydroxyl group of about 0.02 mol to 2 mol with respect to 1 mol of the isocyanate group.
Further, polyamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p- (m-) phenylenediamine, piperazine and derivatives thereof, 2-hydroxytrimethylenediamine, diethylenetriamine, triethylenetriamine. , Triethylenetetramine, tetraethylenepentamine, and an amine adduct of an epoxy compound.
[0078]
Microcapsules can also be produced using water-soluble polymers. The water-soluble polymer at this time may be any of a water-soluble anionic polymer, nonionic polymer, and amphoteric polymer.
Anionic polymers include -COO- and -SO₂-Specific examples include arabic gum, alginic acid, sulfated starch, sulfated cellulose, gelatin derivatives such as phthalated gelatin, (meth) acrylic acid-based (co) polymers, and vinylbenzenesulfone. Examples of the acid-based (co) polymer, carboxy-modified polyvinyl alcohol, the nonionic polymer include polyvinyl alcohol and hydroxyethyl cellulose, and the amphoteric compound includes gelatin and the like. In particular, gelatin, gelatin derivatives, polyvinyl alcohol Is preferred.
The water-soluble polymer is used as an aqueous solution of 0.01 wt% to 10 wt%.
[0079]
In such second and third recording materials, the average particle size of the capsule is preferably 20 μm or less, and particularly preferably 5 μm or less from the viewpoint of resolution. On the other hand, when the capsule is too small, the surface area with respect to a certain solid content becomes large and a large amount of wall agent is required. For this reason, 0.1 micrometer or more is preferable.
[0080]
The electron donating colorless dye may be present in a solution state in the microcapsule or may be present in a solid state.
When the electron-donating colorless dye is present in a solution state, the dye may be encapsulated in a state dissolved in a solvent. The amount of the solvent at this time is preferably 1 to 500 parts by weight with respect to 100 parts by weight of the electron donating colorless dye. As the solvent used for encapsulation, the same solvent as used for emulsification of the photocurable composition can be used. Further, at the time of microencapsulation, a volatile solvent such as an acetate solvent may be used in combination with another solvent as an auxiliary solvent for dissolving the electron donating colorless dye.
[0081]
In addition to the image forming layer, the second and third recording materials may have various layers such as a protective layer and an intermediate layer, but it is preferable to add a matting agent to the protective layer.
Examples of the matting agent include inorganic particles such as silica and magnesium oxide, resin particles such as polymethyl methacrylate and polystyrene, and starch particles such as carboxy starch. In particular, polymethyl methacrylate particles and silica particles are preferably used. . As silica particles, FUJI-DEVISON CHEMICAL LTD.'S Cyloid AL series and the like can be used.
The particle size of the matting agent is preferably 1 μm to 20 μm, and the addition amount is 2 mg / m.²~ 500mg / m²Is preferred.
[0082]
It is preferable to use a curing agent in each of the image forming layer, the intermediate layer and the protective layer of the recording material. In particular, it is preferable to use a curing agent in the protective layer to reduce the tackiness of the protective layer.
As the curing agent, a “gelatin curing agent” used in the production of photographic recording materials is useful, and specifically, chromium alum, zirconium sulfate, boric acid, 1,3,5-triacroyl-hexahydro-s-triazine, 1,2-bisvinylsulfonylmethane, 1,3-bis (vinylsulfonylmethyl) propanol-2, bis (α-vinylsulfonylacetamido) ethane, 2,4-dichloro-6-hydroxy-s-triazine sodium salt, 2,4,6-triethylenino-s-triazine and the like are preferably exemplified.
In addition, about 0.5 to 5 weight% of the addition amount of the hardening | curing agent in each layer is preferable with respect to a binder.
[0083]
In addition, colloidal silica may be added to the protective layer in order to reduce its adhesiveness.
As the colloidal silica, for example, Snowtex 20, Snowtex 30, Snowtex C, Snowtex O, Snowtex N, etc., manufactured by Nissan Chemical Co., Ltd. can be used. About% by weight is preferred.
Further, a fluorescent whitening agent for increasing the whiteness of the recording material or a blue dye as a bluing agent may be added to the protective layer.
[0084]
When the second and third recording materials are multicolor recording materials, for example, a photocurable composition that is sensitive to light having a different wavelength from microcapsules containing electron-donating colorless dyes that develop colors in different hues. May be used, and an intermediate layer containing a filter dye may be provided between the light-sensitive and heat-sensitive layers.
The intermediate layer mainly comprises a binder and a filter dye, and may contain additives such as a curing agent and a polymer latex as necessary.
The filter dye can be added to a desired layer, particularly an intermediate layer, by emulsifying and dispersing by an oil-in-water dispersion method or a latex dispersion method. In the oil-in-water dispersion method, the surfactant is dissolved in either a single liquid or a mixed liquid of either a high-boiling organic solvent having a boiling point of, for example, 175 ° C. or higher and a so-called auxiliary solvent having a boiling point of, for example, 30 ° C. to 160 ° C. In the presence of water, it is finely dispersed in an aqueous medium such as water or an aqueous gelatin solution.
Specific examples of latex dispersion process, latex for curing and impregnation are described in U.S. Pat. No. 4,199,383, and suitable latexes include, for example, (methacrylate) ) A copolymer latex of an acrylic acid ester and an acid monomer such as acrylic acid is preferred.
[0085]
In the second and third recording materials, as a binder for each layer such as a protective layer, an image forming layer, and an intermediate layer, water-soluble used for emulsifying and dispersing the photocurable composition and encapsulating an electron-donating colorless dye. In addition to water-soluble polymers, use acrylic resins such as polystyrene, polyvinyl formal, polyvinyl butyral, polyvinyl alcohol, and polymethyl acrylate, solvent-soluble polymers such as phenol resin, ethyl cellulose, epoxy resin, and urethane resin, or latex of these polymers. You can also. Of these, gelatin and polyvinyl alcohol are preferred.
[0086]
Further, a surfactant may be used for each of the layers of the second and third recording materials for the purpose of coating aid, antistatic property, improvement of slipperiness, emulsification dispersion, adhesion prevention and the like.
As the surfactant, for example, nonionic surfactants such as saponin, polyethylene oxide and derivatives thereof, alkyl sulfonate, alkyl sulfate, N-acyl-N-alkyl taurine and the like can be used as necessary.
In addition to the additives described so far, if necessary, dyeing agents that prevent irradiation and halation, UV absorbers, plasticizers, fluorescent brighteners, coating aids, curing agents, antistatic agents, A slipping improver or the like may be added.
[0087]
Such a recording material A (first recording material, second recording material, and third recording material) is prepared by applying a coating solution (emulsion) containing the components of each layer, using a solvent as necessary. And it can produce by apply | coating by a well-known means and drying.
As the solvent, various solvents used for the production of recording materials can be used. Specifically, water, alcohols such as ethanol and isopropanol, halogen solvents such as ethylene chloride, and ketones such as cyclohexanone and methyl ethyl ketone. , Esters such as methyl cellosolve and ethyl acetate, toluene, xylene and the like are exemplified, and if necessary, a mixture of a plurality of types is used. Further, for the purpose of improving coating properties and charging, Various surfactants such as nonionic, anionic, cationic, and fluorine may be added.
As a coating method, known methods such as a blade coater, a rod coater, a knife coater, a roll doctor coater, a reverse roll coater, a transfer roll coater, a gravure coater, a kiss roll coater, and a curtain coater can be used. Of course, the coating amount of each paint is adjusted so that the adhesion amount of each layer after drying becomes a predetermined amount.
[0088]
There are no particular limitations on the support of these recording materials A, and various materials used for ordinary recording materials can be used. Specifically, polyester films, polyethylene terephthalate (PET) films, polyethylene naphthalate Examples thereof include resin films such as films, cellulose nitrate films, cellulose ester films, polyvinyl acetal films and polycarbonate films, various metals such as aluminum, zinc and copper, glass and paper.
The recording material A in the illustrated example is a light-transmitting film recording material using, as an example, a transparent PET film as a support.
[0089]
Using such a recording material A, a forming apparatus 10 for creating a print (hard copy) on which a visible image corresponding to image data supplied from an image data supply source R is recorded is basically a recording material. The photosensitive material supply unit 12, the width adjustment unit 14, the image exposure unit 16, the thermal development unit 18, and the discharge tray 80 are configured in the order of conveyance of A. Further, a light source 82 and a line sensor 84 for measuring the density of the recording material A that has been subjected to the thermal development are disposed between the thermal development unit 18 and the tray 80.
In FIG. 1, the drawing is omitted for the sake of simplification of the configuration, but the forming apparatus 10 includes a conveyance roller and a guide for conveying the recording material A in addition to the illustrated members. Various sensors are arranged as necessary.
[0090]
The recording material A is usually a laminate (bundle) of a predetermined unit such as 100 sheets, and is wrapped in a bag or a belt, and is usually stored in a dedicated magazine 20 as the predetermined unit of the laminate. Are supplied to the forming apparatus 10 and used for image formation one by one.
The photosensitive material supply unit 12 (hereinafter referred to as the supply unit 12) takes out one sheet of the recording material A from the magazine 20 and is positioned downstream in the conveyance direction of the recording material A (hereinafter referred to as downstream). 14, loading sections 22 and 24, sheet-fed means using suction cups 26 and 28 disposed in each loading section and supply roller pairs 30 and 32, conveyance roller pairs 34 and 36, and conveyance guide 38, 40 and 42.
[0091]
The loading units 22 and 24 are parts for loading the magazine 20 containing the recording material A into a predetermined position. The forming apparatus 10 in the illustrated example has two loading portions 22 and 24, and both loading portions usually have different sizes (for example, a half-cut size for CT and MRI, and an FCR (Fuji Computed). A magazine 20 for storing the recording material A is loaded.
[0092]
The sheet feeding means arranged in each loading section sucks and holds the recording material A by the suction cups 26 and 28, and conveys the recording material A by moving the suction cups 26 and 28 by a known moving means such as a link mechanism. , And supplied to a pair of supply rollers 30 and 32 arranged in the respective loading sections.
The recording material A supplied to the supply roller pair 30 is guided by the conveyance guides 38, 40 and 42 by the conveyance roller pairs 34 and 36, and on the other hand, the recording material A supplied to the supply roller pair 32 is supplied to the conveyance guide 40 and While being guided by 42, the paper is conveyed to the downstream width adjusting section 14 by the conveying roller pair 36.
[0093]
The width adjusting portion 14 aligns the recording material A in a direction perpendicular to the conveying direction (hereinafter referred to as the width direction), thereby aligning the recording material A in the main scanning direction in the downstream recording portion 16, so-called. The side resist is removed and the recording material A is transported to the downstream image exposure unit 16 by the transport roller pair 44.
There is no particular limitation on the method of side registration in the width adjusting portion 14, for example, a resist plate that makes contact with one end face in the width direction of the recording material A, and an end face that pushes the recording material A in the width direction. Using the pressing means for bringing the recording material into contact with the resist plate, the size in the width direction of the recording material A, in which the resist plate and the conveying direction of the recording material A are regulated in the width direction and similarly contacted with the resist plate Various known methods such as a method using a guide plate or the like that can move according to the above are exemplified.
The side resist may be a so-called center reference based on the center of the recording material A in the width direction or a so-called end surface reference based on the end of the recording material A in the width direction.
[0094]
The image exposure unit 16 (hereinafter referred to as the exposure unit 16) is a part that exposes the recording material A imagewise by light beam scanning exposure, and includes an exposure unit 46 and a sub-scanning conveying unit 48.
[0095]
FIG. 2 shows a conceptual diagram of the exposure unit 16.
The exposure unit 46 deflects the light beam L modulated according to the recorded image in the main scanning direction (perpendicular to the paper surface in FIGS. 1 and 2), and enters the predetermined recording position X. A light source 50, an exposure control device 52 that drives the light source 50, a polygon mirror 54 that is an optical deflector, an fθ lens 56, a falling mirror 58, and a shading correction condition calculation unit 86 (hereinafter referred to as “shading correction condition calculation unit 86”). A condition calculation unit 86) and a data processing unit 88.
Here, the condition calculation unit 86 calculates shading correction data (correction conditions) for correcting density unevenness due to heat development unevenness due to surface temperature unevenness (temperature distribution) of the heat developing unit 18, that is, the heating drum 68, that is, shading. It is a part.
In addition, the exposure unit 46 includes other known light beam scanning devices such as a collimator lens, a beam expander, a surface tilt correction optical system, and an optical path changing mirror that shape the light beam L emitted from the light source. Various members to be arranged are arranged as necessary.
[0096]
The light source 50 is a light source that emits a light beam L in a narrow band wavelength range corresponding to the spectral sensitivity characteristics of the recording material A.
Image data from an image data supply source R such as MRI or CT is sent to the data processing unit 88. The data processing unit 88 receives the shading correction data of the corresponding pixel from the condition calculation unit 86, and performs the correction of the image data, that is, the shading correction according to this.
The shading correction by the condition calculation unit 86 and the data processing unit 88 will be described in detail later.
[0097]
The image data processed by the data processing unit 88 is sent to the exposure control device 52. The exposure control device 52 drives the light source 50 according to the supplied image data, that is, the recorded image, and emits the light beam L modulated according to the image data.
Further, when calculating the shading correction data, the exposure control unit 52 drives the light source 50 so as to form an image with a predetermined uniform density, that is, a solid image over the entire surface of the recording material A.
[0098]
In the forming apparatus 10 of the present invention, the method for modulating the light beam L is not particularly limited, and may be pulse (width or number) modulation or intensity modulation.
Further, in the illustrated example, the exposure controller 52 controls the drive of the light source 50 to perform modulation, and the light beam L is modulated in accordance with the recorded image by direct modulation. External modulation using a spatial modulation element such as an optical modulator), an EOM (electro-optic modulator), or a liquid crystal shutter array may be used.
[0099]
The light beam L thus modulated and emitted from the light source 50 is deflected in the main scanning direction by the polygon mirror 54, adjusted so as to form an image at the recording position X by the fθ lens 56, and by the falling mirror 58. The optical path is changed to enter the recording position X.
The forming apparatus 10 in the illustrated example is an apparatus for recording a monochrome image, and the exposure unit 46 has only one light source 50. However, when the present invention is used for recording a color image, for example, a color photosensitive material is used. An exposure unit having three types of light sources that emit light beams having wavelengths corresponding to the spectral sensitivity characteristics of R (red), G (green), and B (blue) is used.
[0100]
On the other hand, the sub-scanning conveying means 48 has a pair of conveying roller pairs 60 and 62 arranged with the recording position X (scanning line) interposed therebetween, and the recording material A is recorded at the recording position by the conveying roller pairs 60 and 62. While being held at X, it is conveyed in the sub-scanning direction (arrow a direction in FIG. 2) orthogonal to the main scanning direction.
Here, as described above, since the light beam L modulated according to the recorded image is deflected in the main scanning direction, the recording material A is two-dimensionally scanned and exposed by the light beam, and the latent image is recorded. Is done.
[0101]
The recording material A on which the latent image is recorded in the exposure unit 16 is then transported by the transport roller pairs 64 and 66 and transported to the heat developing unit 18.
The thermal development unit 18 is a part that heats the recording material A to perform thermal development to convert the latent image into a visible image, and includes a heating drum 68, an endless belt 70, and a peeling claw 72. Is done.
[0102]
The heating drum 68 is a drum having a built-in heating light source such as a halogen lamp or a heat source such as a heater. The surface of the heating drum 68 is heated and held at a temperature corresponding to the heat development temperature of the recording material A. The recording material A is nipped and conveyed together with the endless belt 70 by rotating to the center.
The endless belt 70 is stretched around four rollers 74 a, 74 b, 74 c and 74 d and pressed so as to be wound around the heating drum 68.
The peeling claw 72 peels the recording material A from the heating drum 68, and is configured to lightly contact and detach from the heating drum 68 corresponding to the conveyance of the recording material A by the heating drum 68.
[0103]
The recording material A carried into the heat developing unit 18 by the conveyance roller pair 66 is nipped and conveyed by the endless belt 70 and the rollers 76 and 78, and is conveyed between the heating drum 68 and the endless belt 70, and the heating drum. The latent image recorded by exposure after being thermally developed by the heating drum 68 while being conveyed according to the rotation of the image 68 becomes a visible image.
When the leading end of the recording material A is conveyed in the vicinity of the peeling claw 72, the peeling claw 72 lightly contacts the heating drum 68 and enters between the heating drum 68 and the recording material A, and the recording material A is heated to the heating drum. Peel from 68.
[0104]
As an example, the temperature of the heating drum 68 is 100 ° C. to 140 ° C. when the first recording material A is used as the recording material A, and 85 ° C. to 150 ° C. when the second and third recording materials are used. C. is exemplified.
Further, the heat development time may be adjusted by changing the conveyance speed according to the type of the recording material A, or by stopping the conveyance after the recording material A is completely stored. The thermal development time is, for example, about 10 seconds to 90 seconds for the first recording material, and about 3 seconds to 60 seconds for the second and third recording materials.
[0105]
Further, when the recording material A is thermally developed, the surface temperature of the thermal development unit 18, that is, the heating drum 68, is a position where the recording material A is wound (whether the recording material A is in contact with the front end side or the rear end side). Etc.) and the specific heat of the recording material A, etc., the temperature decreases, resulting in temperature unevenness, particularly in the transport direction.
For this reason, the thermal developing unit 18 of the forming apparatus 10 of the present invention preferably continues even if the surface temperature of the heating drum 68 is uneven due to thermal development or the like even when printing is continuously output. After waiting for the next recording material A not to be thermally developed, the surface temperature of the heating drum 68 becomes substantially constant over the entire surface, that is, the temperature distribution of the heat developing portion 18 is made substantially constant (the heat distribution of the heat distribution). Initialization) and then heat development.
Therefore, in this case, it is preferable to supply the recording material A from the supply unit 12 and record the latent image in the exposure unit 16 at the same timing in accordance with the substantially constant surface temperature of the heating drum. .
[0106]
For detecting that the surface temperature of the heating drum 68 is substantially constant over the entire surface, various known methods can be used. For example, a method of actually measuring using a thermometer or the like, after heat development An example is a method in which the time required for the surface temperature to become substantially constant over the entire surface is detected by experiments or the like, and when this time has elapsed after the thermal development, detection of the substantially constant state is performed.
[0107]
After the thermal development, the recording material A peeled off from the heating drum 68 by the peeling claw 72 is conveyed outside the apparatus and discharged onto the tray 80.
Here, between the heat developing unit 18 and the tray 80, as shown in FIG. 3, a light source 82 and the amount of light emitted from the light source 82 and transmitted through the recording material A are set at a plurality of points in the main scanning direction. The sensor array 84 is measured so as to sandwich the conveyance path of the recording material A.
As described above, since the recording material A is a film using a transparent support, the concentration of the recording material A is measured by measuring the amount of light emitted from the light source 82 and transmitted through the recording material A with the sensor array 84. Can be measured.
[0108]
In the forming apparatus 10, when calculating shading correction data, as described above, a solid image latent image is formed in the exposure unit 16, and the transmitted light amount of the solid image formed by thermal development is measured by the sensor array 84. Is done. The condition calculation unit 86 calculates the image density from the transmitted light amount measured by the sensor array 84, and calculates shading correction data for each pixel from the image density.
[0109]
In the illustrated example, the sensor array 84 measures the image density formed on the recording material A at five points in the main scanning direction by the sensors 84a to 84e. Although the number of measurement points in the main scanning direction is not limited to five, the temperature distribution on the surface of the heating drum 68 does not fluctuate in a fine cycle, so there is no need to measure with high definition. If the maximum size of A in the main scanning direction is the half-cut short direction (356 mm), about 5 to 10 points are sufficient for the full width of the heating drum 68 in the main scanning direction.
On the other hand, the measurement interval in the sub-scanning direction is not particularly limited, but may be about 5 to 10 points.
For the recording material A other than the maximum size, the number of sensor points of the effective portion for each recording material may be used.
In the illustrated example, the light source 82 uses a rod-shaped light source extending in the main scanning direction, but the present invention is not limited to this, and is a dot-like shape arranged corresponding to each sensor (measurement pixel). A light source may be used. When using a rod-shaped light source such as the illustrated example, it is necessary to calculate the image density in consideration of light amount unevenness in the longitudinal direction of the light source.
[0110]
In the present invention, the method for measuring the image density of the heat-developed recording material A is not limited to the above method, and various known density measuring means can be used. For example, the recording material is non-transparent. In this case, the image density may be measured by measuring reflected light, or the image density may be measured using various densitometers.
[0111]
Hereinafter, the present invention will be described in more detail by explaining the operation of the forming apparatus 10.
First, a method for calculating (updating) shading correction data for shading correction will be described.
When calculating shading correction data (hereinafter referred to as correction data), in response to an instruction to that effect, the recording material A is supplied from the supply unit 12, the side registration is removed by the width adjusting unit 14, and exposure is performed. It is conveyed to the part 16.
The correction data may be calculated using the maximum size recording material A targeted by the forming apparatus 10 and shading correction may be performed using this correction data for all size recording materials. Correction data is calculated for each size of recording material, and shading correction is performed using the corresponding correction data.
[0112]
The recording material A conveyed to the exposure unit 16 is two-dimensionally scanned and exposed by the light beam L emitted from the exposure unit 46 and deflected in the main scanning direction while being sub-scanned and conveyed by the sub-scan conveying means 48. A latent image is recorded.
Here, when calculating (updating) the correction data, exposure by the exposure unit 46 is performed so as to form an image having a uniform density on the entire surface of the recording material A, that is, a solid image (exposure control unit 52). Drives the light source 50). The density of the solid image at this time is not particularly limited, but the density D is preferably about 1 to 1.5.
In the recording of the solid image for calculating the correction data, the latent image is recorded without performing the shading correction.
[0113]
The recording material A on which the latent image of the solid image is recorded in the exposure unit 16 is conveyed to the heat developing unit 18 by a pair of conveyance rollers 64, 66 and the like, inserted between the heating drum 68 and the endless belt 70, and nipped and conveyed. While being heat-developed, the latent image becomes a visible image and a solid image is formed. The solid image is peeled off from the heating drum 68 by the peeling claw 72 and conveyed to the tray 80.
Here, when calculating the correction data, the amount of light emitted from the light source 82 and transmitted through the recording material A is measured by the line sensor 84 and sent to the condition calculation unit 86 as described above.
In order to obtain correction data that enables more accurate shading correction, this thermal development is preferably performed after the surface temperature distribution of the heating drum 68 is substantially constant over the entire surface.
[0114]
The condition calculation unit 86 calculates each density of the measurement point (pixel) from the light amount measurement result by each of the sensors 84a to 84d of the line sensor 84, and interpolates the density of the measurement point by a known method such as linear interpolation, Correction data of all pixels recorded on the recording material A is calculated. Alternatively, after correcting the correction data of the measurement points, the correction data of all the pixels may be calculated by interpolating the correction data.
In the present invention, correction data for all pixels may be calculated and stored in the condition calculation unit 86, or only the correction data (density) of the measurement point may be stored in the condition calculation unit 86. The correction data for all pixels may be calculated when the exposure unit 16 records a latent image.
The correction data calculation method is not particularly limited, and may be the same as the known shading correction data calculation method. For example, a method of calculating, for each pixel, a correction coefficient capable of making the density of the solid image uniform by multiplying the image data with the lowest density pixel measured from the solid image as a reference, and using the correction coefficient as the correction data Is exemplified.
[0115]
Such calculation of correction data (or recording of solid images and density measurement therefor) may be performed periodically every time a predetermined number of images are formed, depending on the operation time of the apparatus or the heating time of the heating drum 68. May be performed periodically, or may be appropriately performed according to the operator's judgment such as detection of density unevenness, or may be performed in combination.
[0116]
The image formation by the forming apparatus 10 is basically performed as follows using the (shading) correction data set as described above.
When an instruction to start image formation is issued, similarly, a recording material A of a corresponding size is supplied from the supply unit 12, the side registration is removed by the width adjusting unit 14, and the sheet is conveyed to the exposure unit 16.
[0117]
Image data from the image data supply source R is sent to the data processing unit 88, and the data processing unit 88 responds from the condition calculation unit 86 in synchronization with the conveyance of the recording material A to the exposure unit 16. The pixel correction data is received and used to perform image data correction, that is, shading correction, for example, by multiplying the image data by the correction coefficient. Further, predetermined image processing such as correction by calibration is performed on the image data. And output to the exposure control device 52.
The exposure control device 52 drives the light source 50 according to the supplied image data, that is, the recorded image, and emits the light beam L modulated according to the image data. The light beam L emitted from the light source 50 is deflected in the main scanning direction by the polygon mirror 54, adjusted by the fθ lens 56, reflected by the falling mirror 58, and enters the recording position X.
[0118]
On the other hand, the recording material A conveyed to the exposure unit 16 is light that is modulated in accordance with the recorded image and is changed in the main scanning direction, which is emitted from the exposure unit 46 while being sub-scanned and conveyed by the sub-scan conveying unit 48. Two-dimensional scanning exposure is performed by the beam L, and a latent image is recorded.
[0119]
The recording material A on which the latent image is recorded in the exposure unit 16 is transported to the heat developing unit 18 by a pair of transport rollers 64, 66, etc., and is inserted between the heating drum 68 and the endless belt 70 so as to be nipped and transported. Then, the latent image becomes a visible image and an image is formed.
Here, the temperature unevenness of the heat developing unit 18, that is, the heating drum 68, the temperature change caused by the heat development, and the temperature unevenness resulting therefrom are not dependent on the image density of the recording material A and are always the same pattern. Therefore, according to the present invention, a solid image is recorded, (shading) correction data is calculated from an image obtained by heat development with the heating drum 68, and the exposure is performed by shading correction of the image data using this. Further, it is possible to stably form a high-quality image without density unevenness due to temperature unevenness of the heating drum 68, that is, without shading.
[0120]
In order to obtain a high-quality image with shading corrected more preferably, the thermal development is preferably performed after the surface temperature distribution of the heating drum 68 becomes substantially constant over the entire surface.
[0121]
The recording material A that has been developed is peeled off from the heating drum 68 by the peeling claw 72 and conveyed to the tray 80 as a print (hard copy) on which a visible image is formed.
[0122]
The shading correction method and the image forming apparatus of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. Of course it is good.
For example, the forming apparatus 10 shown in the drawing includes a density measuring unit for calculating correction data. However, the present invention is not limited to this, and a recording material on which a solid density image is similarly formed. A configuration may be adopted in which A is output, this density is measured using an external densitometer, and this is input to the image forming apparatus, and the image forming apparatus calculates and stores correction data.
[0123]
【The invention's effect】
As described above in detail, according to the shading correction method and the image forming apparatus of the present invention, in image formation using a photosensitive heat developing material, image density unevenness due to temperature unevenness in the heat developing portion, that is, shading. High quality images can be created stably.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an example of an image forming apparatus of the present invention.
FIG. 2 is a schematic view of an image exposure unit of the image forming apparatus shown in FIG.
3 is a conceptual diagram for explaining density measurement of a formed image in the image forming apparatus shown in FIG.
[Explanation of symbols]
10 (Image) forming device
12 (Recording material) supply section
14 Alignment part
16 (Image) Exposure part
18 Thermal development section
20 magazines
22, 24 loading section
26, 28 sucker
30,32 Supply roller pair
34, 36, 44, 60, 62, 64, 66 Pair of transport rollers
38, 40, 42 Transport guide
46 exposure unit
48 Scanning conveying means
50,82 light source
52 Exposure control device
54 Polygon mirror
56 fθ lens
58 Falling mirror
68 Heating drum
70 Endless Belt
72 Peeling nails
74a, 74b, 74c, 74d, 76, 78 rollers
80 trays
84 Sensor array
84a, 84b, 84c, 84d, 84e Sensor
86 (Shading correction) condition calculation unit
88 Data processing section
A Recording material

Claims (10)

The photosensitive heat-developable recording material was imagewise exposed in accordance with image data to record a latent image, and the photosensitive heat-developable recording material on which the latent image was recorded was heat-developed by a heat developing means to form an image. A shading correction method in image formation using a photosensitive heat-developable recording material for creating a hard copy,
The entire surface of the photosensitive heat-developable recording material is uniformly exposed to record a solid latent image, and the photosensitive heat-developable recording material on which the solid latent image is recorded is thermally developed to form a solid image. The density of the formed solid image is measured at a plurality of measurement points smaller than the total number of pixels to create shading correction data for each pixel,
A shading correction method, wherein a photosensitive heat-developable recording material is exposed imagewise with image data corrected using the shading correction data when a hard copy is created, and heat development is performed by the heat developing means.   2. The shading correction according to claim 1, wherein the heat development of the photosensitive heat development recording material on which the solid latent image is recorded and the heat development at the time of producing the hard copy are performed after the temperature distribution of the heat development means is made substantially constant. Method.   The shading correction data is created by interpolating the density at the plurality of measurement points to calculate correction data for all pixels recorded on the photosensitive heat-developable recording material. Shading correction method.   The shading according to claim 1, wherein the measurement of the density of the solid image is performed at a plurality of points in the sub-scanning direction orthogonal to the main scanning direction at a plurality of points in the main scanning direction in the latent image recording. Correction method. Create the shading correction data for each size of the photosensitive thermal development recording material used to create the hard copy,
5. The shading according to claim 1, wherein the image data is corrected using the shading correction data corresponding to a size of a photosensitive heat-developable recording material used for creating the hard copy when the hard copy is created. Correction method. An image exposure unit for imagewise exposing a photosensitive heat-developable recording material according to image data supplied from an image data supply source to record a latent image;
A heat development section for thermally developing the photosensitive heat development recording material on which the latent image is recorded;
A sensor for measuring the image density of the photosensitive heat-developable recording material developed in the heat developing section;
Photosensitive heat-developable recording material in which the entire surface of the photosensitive heat-developable recording material is uniformly exposed by the image exposure unit to record a solid latent image, and the solid latent image thermally developed by the heat-developing unit is recorded A correction data creation unit that measures the image density at a plurality of measurement points smaller than the total number of pixels by the sensor, and creates shading correction data for each pixel from the density measurement result;
An image forming apparatus, comprising: a data correction unit that corrects image data supplied from the image data supply source based on shading correction data generated by the correction data generation unit.   The image forming apparatus according to claim 6, wherein the thermal development unit thermally develops the photosensitive thermal development recording material on which the latent image is recorded after the temperature distribution becomes substantially constant.   The correction data creation unit creates the shading correction data by interpolating densities at the plurality of measurement points and calculating correction data for all pixels recorded on the photosensitive heat-developable recording material. Or the image forming apparatus according to 7;   The sensor is constituted by a sensor array that measures at a plurality of points in the main scanning direction in recording the latent image, and measures the image density at a plurality of points in the sub-scanning direction orthogonal to the main scanning direction. The image forming apparatus according to claim 8. The correction data creation unit creates the shading correction data for each size of the photosensitive heat development recording material used for creating the hard copy,
10. The image formation according to claim 6, wherein the data correction unit corrects the image data using the shading correction data corresponding to a size of a photosensitive heat-developable recording material used for creating the hard copy. apparatus.

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