JP2004122690A - Production method for fluorescent printed matter, fluorescent printed matter, image forming material and authenticity detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method for a fluorescent full color image printed matter by the sublimation thermo-sensitive transfer having excellent forgery preventive property and light resistance, and an image forming material (coloring ribbon), and to detect authenticity of the image by the printed matter. <P>SOLUTION: In the production method for a fluorescent printed matter, a full color image printed by the sublimation thermo-sensitive transfer is covered with a UV cut-off image protecting layer capable of controlling the UV fluorescence of the image by absorbing the UV of a specific wavelength, by using the coloring ribbon for fluorescent printing having on a substrate a coloring material layer of respective colors containing red, green and blue sublimation thermo-sensitive transferability fluorescent dyes and a binder component. A fluorescent printed matter is produced by the method. The coloring ribbon for the sublimation thermo-sensitive transfer printing having the coloring material layer of the respective colors and the UV cut-off image protecting layer are successively formed in a surface order on the same ribbon substrate. The authenticity detecting method comprises the steps of comparing light emitting patterns to the preset specific wavelength, and light emitting patterns generated by irradiation of the image printed matter with a specific wavelength light to judge authenticity by their conformance. <P>COPYRIGHT: (C)2004,JPO

Description

一般式Ｉ中、Ｒは、それぞれ独立して、水素原子；メチル基、エチル基、プロピル基、ブチル基等の炭素数１〜６の直鎖又は分岐アルキル基；塩化メチル基、トリフルオロメチル基等の炭素数１〜６のハロゲン化アルキル基；メトキシ基、エトキシ基等の炭素数１〜６のアルコキシ基を表す。これらの中、好ましくは水素原子、ｔ−ブチル基、メトキシ基及びトリフルオロメチル基を表す。
チオフェン系蛍光色素の具体例を以下に示す。
【００２１】
【化８】

【００２２】
（ＩＩ）β−キノフタロン系蛍光色素
当該色素は、下記一般式ＩＩで表される。
【化９】

一般式ＩＩ中、Ｘは水素原子；塩素、臭素等のハロゲン原子；フェニル、ナフチル、トリル等の置換基を有し得るアリール基を表し、好ましくは水素原子及び臭素原子を表す。Ｙは水素原子；水酸基；メトキシ基、エトキシ基等の炭素数１〜６のアルコキシ基を表し、好ましくは水素原子及び水酸基を表す。Ｚは水素原子；塩化メチル基、トリフルオロメチル基等の炭素数１〜６のハロゲン化アルキル基、メトキシ基、エトキシ基等の炭素数１〜６のアルコキシ基を表し、好ましくは水素原子及びトリフルオロメチル基を表す。
β−キノフタロン系蛍光色素の具体例を以下に示す。
【００２３】
【化１０】

【００２４】
（ＩＩＩ）クマリン系蛍光色素
当該色素は、下記一般式ＩＩＩで表される。
【化１１】

一般式ＩＩＩ中、Ｒ_１及びＲ_２は、互いに独立して水素原子；メチル基、エチル基等の炭素数１〜６のアルキル基；フェニル、ナフチル、トリル等の置換基を有し得るアリール基を表し、これらの中、好ましくは互いに独立して水素原子、メチル基、エチル基を表す。Ｘ及びＹは、互いに独立して水素原子；メチル基、エチル基等の炭素数１〜６のアルキル基；塩化メチル基、トリフルオロメチル基等の炭素数１〜６のハロゲン化アルキル基を表し、これらの中、好ましくは水素原子、メチル基及びトリフルオロメチル基を表す。
クマリン系蛍光色素の具体例を以下に示す。
【００２５】
【化１２】

【００２６】
（ＩＶ）ビススチリルベンゼン系蛍光色素
当該色素は、下記一般式ＩＶで表される。
【化１３】

一般式ＩＶ中、Ｒ_１及びＲ_２は、互いに独立して、水素原子；メチル基、エチル基等の炭素数１〜６のアルキル基；メトキシ基、エトキシ基等の炭素数１〜６のアルコキシ基；塩化メチル基、トリフルオロメチル基等の炭素数１〜６のハロゲン化アルキル基を表し、これらの中、好ましくは互いに独立してメチル基、メトキシ基、トリフルオロメチル基を表す。
ビススチリルベンゼン系蛍光色素の具体例を以下に示す。
【００２７】
【化１４】

【００２８】
（Ｖ）オキサゾール系蛍光色素
当該色素は、下記一般式Ｖで表される。
【化１５】

一般式Ｖ中、Ｘ及びＹは、互いに独立して水素原子；メトキシ基、エトキシ基等の炭素数１〜６のアルコキシ基、；塩化メチル基、トリフルオロメチル基等の炭素数１〜６のハロゲン化アルキル基を表し、これらの中、好ましくは互いに独立して水素原子、メトキシ基、トリフルオロメチル基を表す。
オキサゾール系蛍光色素の具体例を以下に示す。
【００２９】
【化１６】

【００３０】
（ＶＩ）ユーロピウム錯体系蛍光色素
当該色素は、下記一般式ＶＩで表される。
【化１７】

一般式中、Ｒ_１及びＲ_２は、互いに独立して、水素原子；メチル基、エチル基等の炭素数１〜６のアルキル基；メトキシ基、エトキシ基等の炭素数１〜６のアルコキシ基を表し、これらの中、好ましくは互いに独立して水素原子、メチル基、メトキシ基を表す。Ｒ_３〜Ｒ_５は、それぞれ独立して炭素数４以上の鎖状アルキル基、環状アルキル基、を表し、これらの中、好ましくは互いに独立してブチル基、ペンチル基、ヘキシル基、シクロヘキシル基等の炭素数４〜８のアルキル基を表す。
ユーロピウム錯体系蛍光色素の具体例を以下に示す。
【００３１】
【化１８】

【００３２】
本発明において、色材層の形成に使用する蛍光色素は上記の蛍光色素から選ばれるが、その際、色材層を構成するバインダーや有機溶媒との、相溶性・溶解性、更には塗工性等を考慮して選ばれ、通常、蛍光色素としてはメチルエチルケトンに少なくとも５重量％溶解するものが好ましい。
【００３３】
色材層に使用するバインダー成分としては、特に制限はなく、昇華型熱転写用色材リボンに通常使用されているバインダー樹脂から適宜選ばれる。具体的には、ポリカーボネート樹脂、ポリスルフォン樹脂、ポリビニルブチラール樹脂、ポリアセタール樹脂、フェノキシ樹脂、塩化ビニル−酢酸ビニル共重合体樹脂、ポリアリレート樹脂、ポリアミド樹脂、ポリイミド樹脂、ポリエーテルイミド樹脂、ポリエステル樹脂、アクリロニトリル−スチレン共重合体樹脂及びセルロース系樹脂などのバインダー樹脂が挙げられる。これらの中でも、ポリビニルブチラール樹脂、ポリアセタール樹脂、塩化ビニル−酢酸ビニル共重合体樹脂が蛍光色素との相溶性の点で好ましい。
【００３４】
本発明の蛍光色素を含有する色材層には、蛍光色素の長期保存による分解を抑制する目的で安定剤を含有させておくのが好ましい。安定剤としては、昇華感熱転写の際、被転写材の染着層（受容層）へ蛍光色素が移行するのと共に移行するものが望ましく、このような性質を満たす限り特に制限はない。安定剤は、蛍光色素，バインダー樹脂、溶剤、その他の添加剤等色材層を構成する成分に応じ、塗工性等も考慮して適宜市販品の中から選ぶことが出来、例えば、ヒンダードアミン系安定剤、ヒンダードフェノール系安定剤が挙げられる。これらの安定剤の具体例を下記に示す。
【００３５】
【化１９】

【００３６】
本発明の色材層には、更に昇華感熱転写印刷後、色材リボンと被転写材の染着層との剥離性を改善するために、潤滑成分、例えばシリコーン樹脂、アミノ変性或いはエーテル変性の変性シリコーン樹脂、シリコーン変性アクリル樹脂等を添加しても良い。
また、本発明の色材リボンにおいては、基材と色材層との間に、基材と色材層の固着を強めるために易接着層を設けてもよい。易接着層を形成する材料としては特に制限はないが、ポリウレタン樹脂、メタミン樹脂等が挙げられる。
【００３７】
色材層中における蛍光色素、バインダー成分、安定剤及びその他の成分の割合に関し、蛍光色素は、バインダー成分１００重量部に対し、通常０．５〜９０重量部、好ましくは０．５〜７０重量部であり、その他の成分の合計量１００重量部に対し、通常０．３〜８０重量部、好ましくは０．３〜５０重量部である。また、安定剤は、バインダー成分１００重量部に対し、通常、１５〜６０重量部、好ましくは１５〜３０重量部である。　蛍光色素や安定剤の量が上記範囲を超えて、多すぎると色材リボンの表面に析出物が生じやすく、昇華感熱転写条件下で色材リボンと被転写材の染着層との融着が起こりやすくなり好ましくない。
【００３８】
本発明の蛍光印刷用色材リボンにおける色材層を基材上に形成する方法は、特に制限されず、例えば、上記の蛍光色素、バインダー樹脂、安定剤及びその他必要により添加される成分を適当な溶剤に溶解或いは分散させた塗布液を調製し、この塗布液を基材のベースフィルムに塗布し、次いで乾燥することにより形成することが出来る。
溶剤としては、クロロホルム等の塩素化アルカン系溶剤、トルエン、キシレン等の芳香族炭化水素系溶剤、メチルエチルケトン、シクロヘキサノン等のケトン系溶剤、エタノール、イソプロパノール等のアルコール系溶剤、ジオキサン、テトラヒドロフラン等のエーテル系溶剤，Ｎ−メチルピロリドン、ジメチルホルムアミド等のアミド系溶剤が挙げられ、これらは単独でも混合物としても使用される。
【００３９】
Ｒ、Ｇ、Ｂのそれぞれの蛍光色素を含む各色材層は、別々の基材上に設けた各色別のリボンとしても良いし、同一の基材上にＲ、Ｇ、Ｂの各色材層を面順次に設けることも出来る。その場合、後述する紫外線遮断画像保護層や、可視昇華感熱転写色材層と共にパターン化したり、面順次に配列したりすることも出来る。
【００４０】
本発明では、通常の昇華感熱転写プリンターを用い、上記色材リボンの色材層面と被転写材の染着層を重ね合わせ、色材リボンの背面（色材層と反対面）をサーマルヘッドで加熱することによって昇華感熱転写性蛍光色素を染着層に移行させ、フルカラー画像を被転写材に印刷する。
被転写材としては、昇華感熱転写印刷の際、上記色材リボンから昇華感熱転写性蛍光色素が、加熱移行して染着し得る染着性の表面（染着層）を有するものであれば良く、通常の昇華感熱印刷メディアに使用されている受容体も使用することが出来る。
【００４１】
被転写材は、通常、基材上に染着層を有するものであり、染着層にはバインダー成分、剥離性付与物質等が含まれている。バインダー成分としては特に制限されず、例えば、塩化ビニル−酢酸ビニル共重合体樹脂、ポリエステル樹脂、ポリビニルアセタール樹脂、及びこれらの混合樹脂等が挙げられ、剥離性付与物質としては、例えば、シリコーンオイル、変性シリコーンオイル等が挙げられる。染着層の厚みは、通常１〜１０μｍ、望ましくは３〜５μｍである。
基材としては特に制限されないが、例えば、芯材（例えば、紙、ポリエチレンテレフタレート（ＰＥＴ）等のポリエステル樹脂、望ましくは紙）の両面に多孔質樹脂材を貼り合わせたものが挙げられる。多孔質樹脂材としては、多孔質のポリプロピレン、ＰＥＴ等のシートが挙げられるが、多孔質ポリプロピレンシートが望ましい。芯材の厚みは、５０〜１５０μｍ（５０〜１５０ｇ／ｍ^２）、望ましくは８０〜１２０μｍ（８０〜１２０ｇ／ｍ^２）であり、多孔質樹脂材の厚みは２０〜１００μｍ、望ましくは４０〜８０μｍである。
【００４２】
昇華感熱転写では、通常、昇華感熱転写プリンターの内部において、Ｒ、Ｇ、Ｂ３原色光加色混合ポジ画像信号（第１図参照）を、Ｙ、Ｍ、Ｃの減色混合画像信号に変換して印刷を行う。本発明で、昇華感熱転写により蛍光画像印刷を行うには、Ｒ、Ｇ、Ｂ３原色光加色混合ネガ画像信号（第２図参照）を、ＲＧＢの強度が補色のＣＹＭの強度に置き換わった画像信号として入力し、Ｙと置換した緑（Ｇ）、Ｍと置換した青（Ｂ）、Ｃと置換した赤（Ｒ）で印字させることにより、結果として昇華感熱転写によるフルカラー蛍光加色混合発光画像を得ることが出来る。
【００４３】
本発明では、昇華感熱転写印刷により形成されたフルカラー蛍光発光画像の上に、特定波長の紫外線を吸収する紫外線遮断画像保護層を被せ、該画像の紫外線蛍光発光を制御するものである。
蛍光色素は、ブラックライトで発光し、その励起吸収（吸収した光が可視蛍光として放出される）は、通常、２５０〜４００ｎｍにあるが、励起光の波長によりその最大吸収波長、吸収能率、吸収スペクトルの形状は異なる。つまり、蛍光発光画像に対し照射光の波長を変えることによって、紫外線蛍光発光のパターンを変え、色調の異なったフルカラー画像を現出させ得るのである。
【００４４】
蛍光色素により形成されたフルカラー画像に、特定波長の紫外線を吸収する紫外線遮断画像保護層を被せることにより、照射光が同じ紫外線領域内であっても、特定波長の照射光は保護層により吸収・遮断されるので、特定波長光と特定波長と異なる波長光を照射した場合では画像の蛍光発光パターンが相違することになる。又、保護層が無い場合、或いは改変等で印刷物に手が加えられ保護層に変化が生じ紫外線遮断画像保護層が変化し特定波長の紫外線吸収の態様が変化した場合には、特定波長光により生ずる蛍光画像の色調も変わることになる。このような照射光の波長の違い、或いは保護層の状況の違いによって生ずる蛍光発光画像間の違いを利用すれば、フルカラー画像の真偽の効果的な判定を可能にする。
【００４５】
即ち、少なくとも１種の特定波長の紫外線遮断により生ずる蛍光発光パターン、特に色調を予め設定し、そのために、使用する蛍光色素の種類、色材中における色素濃度、蛍光発光させるブラックライトの波長、保護層の紫外線吸収剤の種類・濃度等の各種要素の組合せにつき、実験的に最適な組合せを選択する。そして、この組合せにより構成された蛍光発光印刷物を眞正品とすれば、被検査物の印刷物に特定波長の照射光（検査光に相当）を照射した場合、眞正品の蛍光発光パターンと相違すれば、その物は偽物と判定されるのである。その場合、予め設定する蛍光発光パターンの特定波長として２種類の波長の照射光を用いれば、より高精度で偽造物の識別を可能にすることが出来、２種類の波長としては、ブラックライトに通常用いられているロングウエーブ（３６５ｎｍ）とショートウエーブ（２５４ｎｍ）を用いるのが有利である。
【００４６】
例えば、本発明により原画顔写真（白地バック）を昇華感熱転写により蛍光色素でフルカラー印刷し、紫外線遮断画像保護層で被覆した画像の場合、３画面が重ね印字されるＷ部（写真の無地背景）は、可視光下で無色であり地色と変わらないが、このＷ部にブラックライトのロングウエーブ（３６５ｎｍ）を照射すると白く発光する（白色発光に設定）。これに対し、被検査対象とする印刷物に同じロングウエーブ（３６５ｎｍ）を照射した際、白色発光を生じないか、発光しても白色ではない場合、その印刷物は偽造品と判断される。
また、蛍光染料と保護層の紫外線吸収剤の組合せを変えることによりロングウエーブ照射に対し白色発光（白色発光に設定）するが、ショートウエーブ（２５４ｎｍ）照射に対してはグレーバランスを変化させ（白色発光から変化して色味が加わる）、特定の色調（色味）に発光するように設定することも出来る。従って、蛍光発光パターンをこのような２種の特定波長の照射光に対して設定しておけば、被検査対象印刷物に２種の異なる波長光を照射した場合、両照射光による発光パターンは勿論、少なくともいずれか一方の照射光により蛍光パターンが予め設定した発光パターンと相違すれば、その印刷物は偽物と判るのである。
【００４７】
本発明は、従来の単色の蛍光発光画像の場合と異なりフルカラーの蛍光発光画像であり、色材層の蛍光色素の種類・濃度、保護層の紫外線吸収剤の種類・濃度、照射光の波長等の各種要素を任意に組合せることにより蛍光発光パターンを種々変化させることが出来るので、この予め設定された蛍光発光パターンの発現要素を解析することは極めて困難である。従って、本発明の蛍光印刷物の偽造物の製造は非常に難しく、偽造防止効果が極めて高い印刷物ということが出来る。
また、可視光で認識可能な昇華感熱転写性色素により印画した可視画像（参照画像）に対し所定の色調で蛍光発光する蛍光色素により非可視画像を同一の受像紙上に印画しておき、特定波長光照射による参照画像とのズレによっても、真偽を判断することが出来る。
更に、本発明では蛍光発光によるフルカラー画像を紫外線遮断画像保護層で被うことにより耐光性をも向上させることができるのである。
【００４８】
紫外線遮断画像保護層は紫外線吸収剤とバインダーを含有するが、紫外線吸収剤としては特定波長の紫外線を吸収し画像の紫外線蛍光発光を制御するのに適したものを選択する必要がある。即ち、予め設定する特定波長光を照射した場合の蛍光発光パターンを想定し、使用する蛍光色素の種類、吸収スペクトル、照射光の波長、更には可視光下での着色等の挙動を考慮し、所望の蛍光発光パターンが生じるように紫外線吸収剤を選択するのである。
紫外線吸収剤としては、この様な機能を満たす限り特に制限されないが、通常、ベンゾトリアゾール系紫外線吸収剤、トリアジン系紫外線吸収剤、ベンゾフェノン系紫外線吸収剤等から選ばれる。これらの紫外線吸収剤は入手のし易さ、コスト等の点で市販品から選ぶのが簡便である。紫外線吸収剤それ自体は、紫外線を受けても分解せず、紫外線吸収効率が高いものが望ましい。
【００４９】
ベンゾトリアゾール系紫外線吸収剤として、具体的には、以下の化合物が挙げられる。
【化２０】

【００５０】
また、トリアジン系紫外線吸収剤及びベンゾフェノン系紫外線吸収剤の具体例として、以下の化合物が挙げられる。
【化２１】

【００５１】
紫外線遮断画像保護層に含まれるバインダーとしては、特に制限されず、通常ポリエステル樹脂、塩化ビニル−酢酸ビニル共重合体樹脂、エポキシ樹脂、及びこれらの混合樹脂が挙げられる。
【００５２】
紫外線吸収剤は、バインダー樹脂１００重量部に対し、通常１〜３０重量部、好ましく２〜２５重量部である。紫外線吸収剤の使用量が多すぎると、蛍光印刷画像と紫外線遮断画像保護層との融着不良が起こりやすくなり好ましくない。
蛍光印刷画像を被う紫外線遮断画像保護層の厚みは、通常、０．２〜２μｍ、好ましくは０．５〜１．５μｍである。
【００５３】
蛍光印刷画像を被う方法は特に制限されず、紫外線遮断画像保護層を蛍光印刷画像の上に密着させることが出来る任意の手法で行うことが出来、例えば、基材のベースフィルム上に設けられた紫外線吸収剤及びバインダーを含有する紫外線遮断画像保護層を、蛍光印刷された画像面上に重ね合わせ、ベースフィルの紫外線遮断画像保護層を有しない側の背面からサーマルヘッド等で加熱することにより、該保護層を画像上に接着、融着させることにより被覆出来る。その場合、ベースフィルムには背面からの加熱を円滑にするために、サーマルヘッド等のスムーズな移行を可能にする背面層を設けておくことが好ましく、また、該保護層を剥離層を介してフィルム上に設け、被覆終了後剥離層を剥がすことにより保護層を形成しても良い。
【００５４】
紫外線遮断画像保護層の基材上への形成は、常法により行われ、例えば、バインダー及び紫外線吸収剤を、任意の溶剤に溶解して塗布液を調製し、グラビアコーター、キスコーター、リバースコーター、バーコーター等の通常のコーティング方法を用いて、予め片面に剥離層を反対面に背面層を設けた基材上の剥離層上に塗布液を塗布、乾燥することにより形成される。溶剤としては、紫外線吸収剤及びバインダーを溶解するものであれば特に制限されず、トルエン、キシレン等の芳香族炭化水素系溶剤、クロロホルム等のハロゲン化アルキル有機溶剤、メチルエチルケトン等のケトン系有機溶剤並びにこれらの混合物から適宜使用される。
【００５５】
基材としては、厚さ３〜１５μｍ程度のポリエチレンテレフタレートフィルム等が用いられ、背面層には、変性シリコーン化合物等の通常の昇華感熱転写用色材リボンに施されているものと同等のものが使用される。又、市販されている剥離性の付与されたポリエステルフィルム等を用いて、その上に紫外線遮断画像保護層を設けることことも出来る。
基材上への剥離層の形成及び剥離層の材料は、従来公知の方法及び材料を用いることが出来る。例えば、アクリル系樹脂、塩化ビニル系樹脂、セルロース系樹脂、ゴム系樹脂、ウレタン系樹脂、ポリエステル系樹脂、酢酸ビニル系樹脂、エチレン−酢酸ビニル系樹脂等のホモポリマー、コポリマー或いはこれらの混合物及び必要に応じて剥離性調節剤としてシリコーン樹脂、シリコーングラフトアクリル樹脂並びにシリコーングラフト・ポリエステル樹脂等を添加した有機溶剤溶液或いは分散液を、既知のコーティング方式、例えば、グラビア方式、シルクスクリーン印刷法、ロールコーター法、スプレーコート法、フローコート法、ナイフコート法、エアナイフコート法などにより、一般には乾燥膜厚で０．１ミクロン以上、２ミクロン以下の厚さに塗布して加熱乾燥して形成することが出来る。
【００５６】
本発明では、蛍光印刷画像は、昇華感熱転写性蛍光色素を含む色材層を有する色材リボンを用い昇華感熱転写印刷により被転写材の染着層上に形成されるので、画像を被覆する紫外線遮断画像保護層を、色材リボンの色材層と同一面上に面順次に設けることも出来、それによって感熱転写により画像形成後、その上の保護層を形成させることが出来る。
【００５７】
更に、本発明では昇華感熱転写印刷方式により画像形成がなされることから、蛍光発光する蛍光色素を含む色材層（不可視昇華感熱転写性色材層）と紫外線遮断画像保護層とを有する色材リボンに、可視光で認識可能な昇華感熱転写性色素を含む色材層（可視昇華感熱転写性色材層）を並存させることにより、可視画像と蛍光発光画像とを同一の被転写材に印刷することを可能にするのである。即ち、同一の昇華感熱転写プリンターで、偽造し難い精細な蛍光画像と参照用の可視昇華感熱転写画像（以下、通常画像ともいう）を、単一の被転写材の染着層上に任意のパターンで形成できるのである。
この様な、単一の色材リボン上に不可視昇華感熱転写性色材層と可視昇華感熱転写性色材層とを設ける例としては、図−３及び図−４に示す如く、Ｒ、Ｇ及びＢのそれぞれの色素からなる不可視昇華感熱転写性色材層と可視昇華感熱転写性色材層とをリボンの長手方向に直列に設けることも出来るし、並列に設けることも出来る。
【００５８】
昇華感熱転写プリンターに、通常のＲ、Ｇ、Ｂ画像信号とＲ、Ｇ、Ｂネガ画像信号を組み合わせて送り込み、例えば、図−３に示す形式の色材リボンを用いれば、任意の重なりで通常画像と蛍光画像を単一の染着層に形成することが出来る。又、図−４に示す形式の色材リボンを用いれば、通常画像と蛍光画像を隣接して単一の染着層に形成することが出来る。
【００５９】
更に、本発明の色材リボンには、色材層と共に紫外線遮断画像保護層が設けられており、昇華感熱転写により蛍光画像及び通常画像を形成した後、これらの画像を該保護層で熱転写により被覆することが出来る。該保護層には、特定波長の紫外線を吸収し蛍光画像の紫外線蛍光発光を制御する紫外線吸収剤が含まれているので、この保護層は通常画像に対しては、従来行われている紫外線フィルターとしての保護層としての役割を果たすことが出来る。その結果、印刷画像の耐光性も向上させることが出来る。
【００６０】
昇華感熱転写印刷で通常行われているように、透明基板上に設けられた染着層に本発明方法により、蛍光画像を要すれば通常画像と共に形成し、紫外線遮断画像保護層を被せたのちに、第２の基材に貼り付けたり、或いは剥離可能な染着層に画像を形成し、紫外線遮断画像保護層を被せたのち、剥離した染着層を第２の基材に貼り付けることも出来る。
【００６１】
【実施例】
以下に、実施例により本発明を更に詳細に説明するが、本発明はその要旨を超えない限り以下の実施例によって限定されるものではない。
【００６２】
［参考例］
（Ｉ）蛍光色素、安定剤及び紫外線吸収剤の塗膜性試験
１．最大吸収波長と最大蛍光波長の測定
前述の蛍光色素（Ｎｏ．１〜３４）のそれぞれをエタノールに溶かし、１０^−５ｍｏｌ／Ｌ　溶液として、日立Ｆ−４５００型紫外分光計にて最大吸収波長と最大蛍光波長を測定した。その結果を発光の色の類別（青、緑、赤）と共に表１に示す。尚、表１中、Ｎｏ．は前記蛍光色素番号である。この結果、最大波長は３４０〜３９５ｎｍに分布していることが判る。
【００６３】
【表１】

【００６４】
２．色材層塗布液の塗膜性確認試験
色材リボンに色材層を形成した際の析出物の有無を確認するため、下記組成の色素及び安定剤を用い、塗布試験を行った。なお、色素及び安定剤のＮｏ．は、前記化合物Ｎｏと同一である。
表２　蛍光色素混合物
（Ｂ、Ｇ、Ｒは、それぞれ青、緑、赤の発光色を表す）
【表２】

【００６５】
【表３】

【００６６】
上記色素混合物及び安定剤混合物、並びにバインダーとしてのアセタール樹脂（ＫＳ−５；積水化学工業社製）を表４に記載の組成割合で用い、クロロホルム２０００部に溶解して塗布液を調製した。この塗布液をマイヤーバーにてポリエチレンテレフタレート（ＰＥＴ）フィルム上に塗布した後、１１０℃、３０秒オーブンにて乾燥させて１．０μｍの塗層を形成した。塗層の表面を目視観察し、加熱印画の際に色材リボンと受像層の融着の原因となる析出物の有無を調べた。その結果を表４に示す。
【００６７】
【表４】

【００６８】
３．紫外線遮断画像保護層塗布液への塗膜性確認試験
塗工により保護層形成の際、保護層から紫外線吸収剤等の析出物の生起が生じないことを表５に記載の紫外線吸収剤混合物を用いて確認のために試験を行った。なお、紫外線吸収剤の化合物Ｎｏ．は、前記化合物Ｎｏ．と同一である。
【表５】

【００６９】
上記紫外線安定剤混合物及びバインダーとしてのアクリル樹脂（Ｐａｒａｌｏｉｄ　Ａ−２１　；ロームアンドハース社製）を表６に記載の組成割合で用い、トルエン５００部とメチルエチルケトン５００部の混合溶剤に溶解して塗布液を調製した。この塗布液をマイヤーバーにてＰＥＴフィルム上に塗布した後、１１０℃、３０秒オーブンにて乾燥させて１．０μｍの塗層を形成した。塗層の表面を目視観察し、加熱印画と保護層の融着不良の原因となる析出物の有無を調べ、その結果を表６に示す。この結果、紫外線吸収剤は、バインダー樹脂に対して３０部以下、好ましくは２５部以下であることが判る。
【００７０】
【表６】

【００７１】
（ＩＩ）熱転写用リボン等の作成
１．耐熱滑性層付き基材の調製
蛍光色素含有色材層付きリボンの基材として通常ＰＥＴフィルム（Ｋ２３３Ｅ６．５Ｗ；三菱ポリエステルフィルム社製）を、紫外線遮断画像保護層付きリボンの基材として、剥離性ＰＥＴフィルム（ＡＳ１２；三菱ポリエステルフィルム社製）をそれぞれ使用した。ＰＥＴフィルムの一面及び剥離性ＰＥＴフィルムの未処理面側に、次の配合の塗布液をマイヤーバーにて塗布した後、１１５℃、４５秒間オーブンにて乾燥させて１．２μｍの耐熱滑性層付きＰＥＴ基材を形成した。
【００７２】
耐熱滑性層塗布液配合
タ゛イヤナールＬＲ−３１３（アクリル樹脂；三菱レイヨン社製）　　　　　　８０部
Ｍ−１００２Ｂ（アクリル樹脂；綜研化学社製）　　　　　　　　２０部
ＢＹ１６−８９２　（アミノ変性シリコ−ンオイル；東レタ゛ウコーニンク゛社製）　　　　２部
ＫＰ０１０１（アミノ変性シリコ−ンオイル；信越化学社製）　　　　　　　３部
Ｘ−２２−３７０１Ｅ（カーホ゛キシ変性シリコ−ンオイル；信越化学社製）　　　　５部
ＭＸ−１８０（球状アクリル樹脂；綜研化学社製）　　　　　　　　７部
トルエン　　　　　　　　　　　　　　　　　　　　３００部
メチルエチルケトン　　　　　　　　　　　　　　　２００部
【００７３】
２．蛍光色素含有色材層付きリボンの作成
上記表２及び表３に記載の蛍光色素、安定剤混合物及びアセタール樹脂（ＫＳ−５；積水化学工業社製）を表７に記載の組成割合で用い、クロロホルム２０００部に溶解して色材層用塗布液を調製した。この塗布液を上記１で作成した、耐熱滑性層付き通常ＰＥＴフィルムの非滑性層面にマイヤーバーにて塗布した後、１１０℃、３０秒間オーブンにて乾燥させて１．０μｍの色材層を持つ各蛍光色の各種リボンを作成した。
【００７４】
表７　蛍光発光色材リボン
【表７】

【００７５】
３．紫外線遮断画像保護層付きリボンの作成
表８に記載の紫外線吸収剤及びアクリル樹脂（Ｐａｒａｌｏｉｄ　Ａ−２１　；ロームアンドハース社製）を表７に記載の組成割合で用い、トルエン５００部とメチルエチルケトン５００部の混合溶剤に溶解して塗布液を調製した。この塗布液を上記１で作成した耐熱滑性層付き剥離性ＰＥＴフィルムの剥離性面にマイヤーバーにて塗布した後、１１０℃、３０秒オーブンにて乾燥させて１．０μｍの塗層を有する保護層付きリボンを作成した。保護層付きリボンにつき、日立Ｆ−４５００型紫外分光計を用いて紫外スペクトルを測定し、透過率が５０％以下となる波長を遮断波長とした。その結果を表８に示す。
【００７６】
【表８】

【００７７】
４．染着層付き受像紙の作成
コート紙（１０８ｇ／ｍ^２）の両面に接着樹脂層を施して発泡ポリプロピレンフィルム（厚さ５０μｍ）を貼り合わせた基材の片面に、下記の染着層塗布液をマイヤーバーにて、乾燥塗膜厚みが４μｍとなるように塗布したのち、乾燥させた。乾燥後、４５℃で１週間エージングを行い受像紙とした。この受像紙の地色は白である。
染着層塗布液
ポリビニルフェニルアセタール　　　　　　　１０．０部
塩化ビニル−酢酸ビニル共重合体樹脂　　　　１０．０部
シリコーンオイル　　　　　　　　　　　　　　２．０部
イソシアネート　　　　　　　　　　　　　　　３．０部
メチルエチルケトン　　　　　　　　　　　　　２．０部
トルエン　　　　　　　　　　　　　　　　　　３．０部
【００７８】
［実施例、比較例、参考例］
１．昇華感熱転写印刷
市販の昇華感熱転写印刷プリンター（ＮＶ−ＡＰ１；松下電器産業（株））を用い、当該プリンター用のオーバーコートタイプ・インクリボン（ＶＷ−ＡＰＬＣ３６；松下電器産業（株））のイエロー画面、マゼンタ画面及びシアン画面、並びに保護層画面の各画面を、それぞれ切り取り、上記（ＩＩ）２及び３で作成した青（Ｂ）蛍光リボン、緑（Ｇ）蛍光リボン及び赤（Ｒ）蛍光リボン、並びに紫外線遮断画像保護層リボンを切り取った個所にこの順序でそれぞれ繋ぎ印字リボンとした。受像紙は、上記（ＩＩ）４で作成した受像紙を、当該プリンター用と同一サイズに裁断して用い、印刷は、蛍光発色で図１に示す画像となるように、ネガ画像（図２）データを入力して印画させ蛍光潜像画像を得た。各印刷試験における色材リボンと紫外線遮断画像保護層リボンの組合せ、及び下記の蛍光画像評価試験結果を纏めて表９に示す。
【００７９】
２．蛍光画像評価試験
ａ）白色度（Ｗ部画像白色度）
３画面が重ね印字されるＷ部の白色度を、ＪＩＳ−Ｐ８１２３に準拠して、色差計（ＳＺ−Σ９０；日本電色社製）にて測定した。可視光下での白色度が７５％以上であれば充分な白とされるので、白色受像紙を用いた本試験では地色とほとんど変わらない画像と判断される。
【００８０】
ｂ）発光試験
ブラックライト（ＵＶＧＬ−２５；フナコシ社）照射にて、Ｗ部画像の発光状態を観察した。
ｂ−１：ブラックライト照射Ｗ部発色（ロングウエーブ）
ロングウエーブ（３６５ｎｍ）紫外線照射にて、赤、青、緑の発色があること並びに３画面が重ね印字されるＷ部が白く発光（白色発光）することを確認した。
ｂ−２：ブラックライト照射Ｗ部発色（ショートウエーブ）
ショートウエーブ（２５４ｎｍ）紫外線照射にて、Ｗ部の発色状態の変化（白色〜色味）、即ちグレーバランスを変化を観察した。
【００８１】
ｃ）耐光試験（フェード試験後Ｗ部発色）
ＪＩＳ−Ｌ０８４３に準拠し、キセノンフェードメーターにて１時間及び３時間光照射後、ブラックライトにてロングウエーブ（３６５ｎｍ）紫外線照射にて画像の発色があるか否かを確認した。キセノン照射１時間は、室内蛍光灯下に約１ヶ月暴露した状況と判断され、この条件で発色すれば通常の使用に問題無いとと考えられるが、室内蛍光灯下に約３ヶ月暴露した状況と判断されるキセノン照射３時間でも発色するのがより望ましい。
【００８２】
表９　印画及び評価結果
【表９】

【００８３】
以上の実施例及び比較例の結果は、下記のことを示す。
１）本発明で得られる蛍光画像の白色度は７５％以上であり、実質的には地色と差が無く、優れた潜像状態の画像が得られる。
２）参考例及び実施例１から明らかな様に、紫外線遮断保護層の遮断波長が４００ｎｍ以上では発光しないので、保護層の紫外線吸収剤の選択には遮断波長が４００ｎｍ未満となるように留意するが、又遮断波長が２８０ｎｍ以下では耐光性に留意し安定剤の選定を要する。
３）紫外線遮断保護層の設置により耐光性が改善されるが（実施例５と比較例３）、色材層に安定剤を添加すると蛍光画像の耐光性が更に改善されことが明らかでる（実施例５と実施例８）。
４）色材層に含有させる蛍光色素は、単独でも２以上混合しても良い（実施例９，１０）。
５）同じ紫外線遮断保護層が同じでも各色材リボンの組合せを変える、或いは同一の各色材リボンの組合せでも遮断波長の異なる紫外線遮断保護層を組み合わせることにより、ショートウエーブ照射ではグレーバランスの変化（白色発光から変化して色味が加わる）が生ずることがある。
６）遮断波長が同じ紫外線遮断保護層でも、該保護層に含まれる紫外線吸収剤の種類、配合比率の違いによりショートウエーブ照射でのグレーバランスの変化が生じる（実施例２５〜２９）。
【００８４】
【発明の効果】
本発明によれば、昇華感熱転写性蛍光色素を用いた昇華感熱印刷によるフルカラー画像に、特定波長の紫外線を吸収して該画像の紫外線蛍光発光を制御し得る紫外線遮断画像保護層を被せることにより、特定波長光の照射による蛍光発光画像の色調を変化させることが出来る。よって、本発明で得られる該保護層で被覆されたフルカラー画像の発光は、保護層、蛍光色素、照射波長の組合せにより複雑に制御することが出来るので、フルカラー画像の偽造防止効果が極めて高く、しかも、保護層により実用にも耐え得る耐光性を有するのである。従って、本発明により得られる蛍光発光印刷物は、偽造防止に優れた各種証明書及び証券等に利用することが出来る。更に、本発明は、このような蛍光発光印刷物を得るのに好適な昇華感熱転写印刷用の色材リボンを提供することができるので、工業的価値が高い。
【図面の簡単な説明】
【図１】赤（Ｒ）、緑（Ｇ）、青（Ｂ）３原色光加色混合ポジ画像の原理を示す説明図
【図２】赤（Ｒ）、緑（Ｇ）、青（Ｂ）３原色光減色混合ネガ画像の原理を示す説明図
【図３】可視昇華感熱転写性色材層領域と不可視昇華感熱転写性蛍光色材層領域とがリボンの長手方法に直列に設けられている色材リボンの説明図
【図４】可視昇華感熱転写性色材層領域と不可視昇華感熱転写性蛍光色材層領域とがリボンの長手方法に並列に設けられている色材リボンの説明図[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a fluorescent light-emitting printed material suitably used for preventing forgery of various certificates and securities, a fluorescent light-emitting printed material, and a color material ribbon preferably used for obtaining the fluorescent light-emitting printed material, Further, the present invention relates to a method of determining the authenticity of the fluorescent light-emitting printed matter.
[0002]
[Prior art]
In order to prevent counterfeiting of various certificates, an image or a fine pattern (hereinafter sometimes referred to as an "image") using a fluorescent substance, often a fluorescent pigment, is secretly incorporated, and only the persons concerned are exposed to ultraviolet light (normally). Irradiation with black light) makes it possible to easily determine whether or not the image is a counterfeit from the expression of a fluorescent image.
However, as knowledge of forgery prevention has spread, a simple fluorescent image has become insufficient as a forgery prevention technology, and various methods have been proposed.
[0003]
Japanese Patent Application Laid-Open No. 7-68946 discloses that a transfer layer for forming a pattern or a character on a surface of an information display section by a thermal sublimation heat-sensing method or a hot-melt transfer method. And a translucent phosphor layer (hereinafter, referred to as a phosphor layer) and an ultraviolet-cutting heat-sensitive transfer layer. The phosphor layer is a phosphor layer having a predetermined pattern or character pattern. It is described. In addition, it describes that a fluorescent dye such as Brilliant Sulfolaviret yellow HG, Eosine Rhodamine G, Rhodamine B (trade name) is used as the fluorescent dye.
[0004]
Then, the surface of the information display portion is aligned with the surface of the ultraviolet ray-cutting heat-sensitive adhesive layer of the transfer body, and the information is transferred by thermal transfer using a thermal head from the base material side, and then the base material is peeled off to display the information. On the surface of the portion, a phosphor layer (phosphor image) is formed via an ultraviolet-cutting heat-sensitive adhesive layer. Therefore, when information is tampered with the phosphor layer removed, the tampering can be detected by the presence or absence of the phosphor, since the phosphor layer is removed.
However, such forgery prevention based on the presence or absence of the phosphor is based on the premise that the phosphor image portion attached to the information display portion is damaged when the information display portion is rewritten. In addition, in the case of a single-color fluorescent image, it is expected that a skilled person having a high level of falsification technology can easily reproduce a phosphor image, which is not necessarily a high level of forgery prevention technology.
[0005]
Further, Japanese Patent Application Laid-Open No. 7-68946 only describes that a phosphor layer is provided with a pattern or a character in a single color, but does not describe anything about forming a fluorescent emission single image in a full color. . That is, all of the organic fluorescent dyes described in JP-A-7-68946 are fluorescent dyes that are colored even under visible light, Brilliant Sulfolaviret yellow yellow HG is turbid yellow, {Eosine Rhodamine} G is magenta, and Rhodamine B Is colored blue-violet and cannot be used for the three primary colors of invisible fluorescent full color. Therefore, using these dyes, in order to make it difficult to see under visible light, a single color, and form a fluorescent dye alone image at low density, as shown in FIG. 2 of the publication, It is necessary to set some design on the background. The publication also discloses that it can be used for a full-color image whose hue changes upon irradiation with ultraviolet light by mixing it with the other three visible primary colors. There is no description or suggestion about obtaining a dye-only image.
[0006]
Japanese Patent Application Laid-Open No. 10-35089 discloses that one substrate includes a first image area including a first colorant that emits visible light by fluorescence and a spectral distribution different from the first spectral wavelength distribution by fluorescence. An image forming body that emits visible light having a wavelength distribution and includes a second image region including a second colorant and a third image region including a third colorant is described. Using three colors of red (R), green (G), and blue (B) (hereinafter, may be simply abbreviated as R, G, and B) as three colorants, and forming an image by thermal transfer. Are also described.
However, the publication discloses only one line in the case of halftone printing related to the thermal transfer method, and the halftone printing discloses area density gradation printing in which the dislocation amount of a color material is invariable, that is, melt thermal transfer. It is just that. In the fusion thermal transfer, the colors of RBG cannot be superimposed, and if the correlation between the halftone dots and the color density is found by carefully analyzing the image, forgery can be performed relatively easily.
[0007]
That is, although the invention described in the above publication uses a fluorescent color image of three primary colors of RGB to prevent forgery, it is more complicated than a single color fluorescent color image, but is an area density gradation image. If the correlation between the halftone dots and the color density is found out by the detailed analysis, it becomes relatively easy to forge.
In addition, in order to combat the forgerier forgery in recent years, it is not sufficient to simply increase the complexity of the fluorescent image itself using a full-color fluorescent image, and a further improvement in security is desired.
On the other hand, in order to practically use a technique for forming a full-color fluorescent image by sublimation thermal transfer printing, it is necessary to ensure light resistance. That is, the sublimable fluorescent dye, which is an organic substance, is decomposed by the strong light energy of ultraviolet rays, and it has been a barrier to practical use that sufficient light resistance cannot be secured.
[0008]
The above-mentioned Japanese Patent Application Laid-Open No. 10-35089 describes that a protective layer is provided for protecting an image, and the protective layer emits light from ultraviolet light, which is excitation light, or fluorescent ink, such as an acrylic resin. It states that it must be transparent to both visible light. That is, this protective layer is exclusively used to cover the surface of the full-color image so as not to be exposed, and high ultraviolet transmittance is essential, and no measures against light resistance have been taken at present. In addition, the publication describes that an ultraviolet absorbing layer is provided, but the ultraviolet absorbing layer is provided to prevent fading of a visible image below a fluorescent image, and in order not to hinder fluorescent coloring, An ultraviolet absorbing layer is applied below the fluorescent image and above the visible image. (4) As described above, the ultraviolet absorbing layer increases the degree of freedom in the layout of the fluorescent light-emitting image, and is not formed on the surface of the fluorescent light-emitting image.
[Patent Document 1] JP-A-7-68946
[Patent Document 2] JP-A-10-35089
[0009]
[Problems to be solved by the present invention]
If a method is used in which multiple primary colors are printed with different densities overlaid on the same point, such as the point density gradation by the sublimation thermal transfer printing method, there are many combinations of coloring hues and densities. Image is obtained, and the effect of preventing forgery is higher than that of a simple area gradation image. Therefore, an object of the present invention is to provide a printed material of a fluorescent emission full-color image by sublimation thermal transfer, which is excellent in forgery prevention and has sufficient light resistance in practical use. Of the present invention is also provided. It is a further object of the present invention to provide a method for detecting the authenticity of an image printed matter, in which duplication is not easy and the forged article is identified using such a full-color fluorescent light-emitting printed matter having a high anti-counterfeiting effect.
[0010]
[Means for Solving the Problems]
Under such circumstances, the present inventors have found that two types of commonly used black light devices are usually mounted, a long wave having a maximum intensity of 365 nm and a short wave having a maximum intensity of 254 nm. Focusing on the fact that the combination of these wavelength light and fluorescent dye, it is possible to express a specific fluorescent color, and by utilizing this specificity that the latent image by the fluorescent dye appears We have learned that effective counterfeit prevention can be achieved.
Then, a full-color image formed by sublimation thermal transfer using a sublimable fluorescent dye is covered with an ultraviolet-shielding image protective layer that can change the color tone even in the same ultraviolet region due to the difference in the wavelength of the irradiated light. The present inventors have found that a novel fluorescent light-emitting printed material capable of controlling light emission in a complicated manner, further improving the effect of preventing forgery of a full-color image, and achieving light resistance that can be put to practical use can be obtained, thereby achieving the present invention.
[0011]
That is, a first gist of the present invention resides in an image for fluorescent printing having a color material layer of each color including at least one of R, G, and B sublimation heat transferable fluorescent dyes and a binder component on a base material. Using a forming material, a full-color image subjected to sublimation thermal transfer printing is coated with an ultraviolet blocking image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling the ultraviolet fluorescent light emission of the image. It is in the manufacturing method.
[0012]
The second gist of the present invention is to use an image forming material for fluorescent printing having a color material layer of each color including at least one of R, G, and B sublimation thermal transfer fluorescent dyes and a binder on a base material. A sublimation thermal transfer printed full-color image is coated with a UV-blocking image protective layer capable of absorbing UV light of a specific wavelength and controlling the UV fluorescent light emission of the image, or a R, G Image formation for fluorescent printing, comprising a color material layer comprising a sublimation heat transferable fluorescent dye of R and G and a color material layer comprising a sublimation heat transfer colorant recognizable by visible light of R, G and B Fluorescent full-color image and full-color image recognizable by visible light, printed by sublimation thermal transfer printing using a material, are covered with an ultraviolet blocking image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling the ultraviolet fluorescent light emission of the image. Fluorescence Resides in the light printed matter.
[0013]
A third aspect of the present invention is to provide a color material layer containing a sublimation-sensitive heat transferable fluorescent dye of R, G, and B on a substrate, and a sublimation sensation of R, G, and B that can be further recognized by visible light if necessary. An image forming material is provided with a color material layer comprising a color material layer containing a heat transferable colorant, and an ultraviolet blocking image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling ultraviolet fluorescent light emission in a plane-sequential manner.
[0014]
The fourth gist of the present invention is that a true image print produced by the method of the present invention is provided with a color tone of a fluorescent image developed by irradiation of at least one specific wavelength light within an ultraviolet region of 250 to 400 nm, and The authenticity of the image printed matter, wherein the authenticity of the image printed matter, which is obtained by irradiating the image printed matter of the inspection object with light having the same wavelength as the irradiation light, is determined based on the compatibility between the two. It lies in the detection method.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The fluorescent light-emitting printed material of the present invention is an image forming material for fluorescent printing, having a color material layer containing R, G, and B sublimation-sensitive heat transferable fluorescent dyes on a substrate, which is manufactured according to the manufacturing method of the present invention. A fluorescent light-emitting printed material obtained by coating a full-color image subjected to sublimation thermal transfer printing using an ultraviolet ray shielding image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling the ultraviolet fluorescent light emission of the image.
In addition, other fluorescent light-emitting printed materials include, on a base material, a color material layer containing R, G, and B sublimation-sensitive thermal transfer fluorescent dyes, and a sublimation-sensitive thermal transfer colorant that can be recognized by visible light of R, G, and B. A full-color image is formed by sublimation thermal transfer printing using an image forming material in which a color material layer comprising a color material layer including, and an ultraviolet blocking image protection layer region capable of absorbing ultraviolet light of a specific wavelength are provided in a face-to-face order, Next, it is a fluorescent light-emitting printed matter obtained by coating the image with an ultraviolet-shielding image protective layer so that the ultraviolet fluorescent light emission of the image is controlled.
[0016]
<Image forming material>
In the production of the fluorescent light-emitting printed material of the present invention, an image forming material (hereinafter, sometimes simply referred to as a color material ribbon) used for forming a full-color image by sublimation thermal transfer printing includes red (R), green (G) and blue (B) having a coloring material layer containing at least one of the sublimation thermal transfer fluorescent dyes and a binder, and a conventional sublimation thermal transfer printing (basically adjusted by subtractive color mixing of three primary colors). The sublimation thermal transfer dyes contained in the color material layers of the three color material ribbons of yellow (Y), magenta (M), and cyan (C) are subjected to R, G, and B fluorescence. It can be produced by replacing with a fluorescent dye which is color-forming and substantially colorless with ordinary visible light.
Here, “substantially colorless” means that when printed by sublimation thermal transfer printing, the color to be exhibited under normal visible light is acceptable up to the same degree of yellowness as the whiteness of the base (usually yellowish). The term “acceptable yellowishness” means that a whiteness of 75% or more in a whiteness measurement in accordance with JIS-P8128 indicates the degree to which a normal white base is obtained.
[0017]
The base material of the coloring material ribbon is not particularly limited, and a normal base film is used, for example, a polyethylene terephthalate film, a polyamide film, an aramid film, a polyimide film, a polycarbonate film, a polyphenylene sulfide film, a polysulfone film, and a polypropylene film. Among them, a polyethylene terephthalate film is frequently used in terms of mechanical strength, heat resistance and price, and a biaxially stretched polyethylene terephthalate film is particularly preferable.
The thickness of the base film is generally 1 to 30 μm, preferably 2 to 10 μm.
[0018]
It is preferable to provide a heat-resistant lubricating layer on the back surface of the base film (the surface opposite to the colorant layer) to enable the sublimation thermal transfer head to run smoothly. As the heat-resistant lubricating layer, the material of the heat-resistant lubricating layer used for a coloring material ribbon for normal sublimation thermal transfer printing can be applied, and specifically, for example, described in JP-A-10-138650 As described above, necessary components such as lubricants, various additives, and solvents are blended with a polymer compound containing as a (meth) acrylate component of an aliphatic polycyclic alcohol having a skeleton such as norbornane, adamantane, and cubane. Then, the composition is formed by coating and drying the composition on a base film. The thickness of the heat-resistant lubricating layer is usually 0.1 μm or more, preferably 1 μm or more, and usually 5 μm or less, preferably 3 μm or less.
[0019]
The coloring material layer provided on the base material contains a sublimation heat transferable fluorescent dye (hereinafter, sometimes simply referred to as a fluorescent dye) and a binder component. As the fluorescent dye, a known fluorescent dye, particularly an organic fluorescent dye, is used. It is desirable to select a dye satisfying the following characteristics (1) to (3) from the above.
(1) Be substantially colorless with visible light.
A property required for preventing forgery of a fluorescent light-emitting printed material, which is to satisfy the whiteness defined as the above-mentioned “substantially colorless”.
To this end, the fluorescent dye has a structure in which a conjugated system exists in the molecule and the carbon atom system forming the conjugated system in the molecule does not have a side-chain conjugated system, that is, a cyclic conjugated system and the same. It is preferable to select one having a structure composed of a connected linear conjugate system.
(2) To emit strong fluorescence.
It is preferable that the intensity of the fluorescence spectrum emitted by excitation light having a wavelength in a normal ultraviolet light region (400 nm to 250 nm) is relatively strong, and for example, the light quantum efficiency is about 3% or more.
(3) To exhibit clear RGB fluorescence.
Since the width of the maximum peak is narrow and sharp in the shape of the fluorescence spectrum with respect to the excitation light of the fluorescent dye, a full-color fluorescent image can clearly appear.
[0020]
The fluorescent dye satisfying the above-mentioned properties in the present invention is selected from thiophene-based, β-quinophthalone-based, coumarin-based, bisstyrylbenzene-based, oxazole-based and europium complex-based sublimation heat-transferable fluorescent dyes, and is easily commercially available. It can be appropriately selected and used from the products. Hereinafter, these dyes will be described more specifically.
(I) Thiophene-based fluorescent dye
The dye is represented by the following general formula I.
Embedded image

In the general formula I, R is each independently a hydrogen atom; a linear or branched alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group; a methyl chloride group, a trifluoromethyl group A halogenated alkyl group having 1 to 6 carbon atoms, such as a methoxy group or an ethoxy group; Among these, a hydrogen atom, a t-butyl group, a methoxy group and a trifluoromethyl group are preferred.
Specific examples of the thiophene-based fluorescent dye are shown below.
[0021]
Embedded image

[0022]
(II) β-quinophthalone fluorescent dye
The dye is represented by the following general formula II.
Embedded image

In the general formula II, X represents a hydrogen atom; a halogen atom such as chlorine and bromine; and an aryl group which may have a substituent such as phenyl, naphthyl and tolyl, preferably a hydrogen atom and a bromine atom. Y represents a hydrogen atom; a hydroxyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group, preferably a hydrogen atom and a hydroxyl group. Z represents a hydrogen atom; a halogenated alkyl group having 1 to 6 carbon atoms such as a methyl chloride group and a trifluoromethyl group; and an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group. Represents a fluoromethyl group.
Specific examples of the β-quinophthalone-based fluorescent dye are shown below.
[0023]
Embedded image

[0024]
(III) Coumarin-based fluorescent dye
The dye is represented by the following general formula III.
Embedded image

In the general formula III, R₁And R₂Each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; and an aryl group which may have a substituent such as phenyl, naphthyl, and tolyl. Independently represents a hydrogen atom, a methyl group, or an ethyl group. X and Y each independently represent a hydrogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group; a halogenated alkyl group having 1 to 6 carbon atoms such as a methyl chloride group or a trifluoromethyl group. Of these, a hydrogen atom, a methyl group and a trifluoromethyl group are preferred.
Specific examples of the coumarin fluorescent dye are shown below.
[0025]
Embedded image

[0026]
(IV) bisstyrylbenzene fluorescent dye
The dye is represented by the following general formula IV.
Embedded image

In the general formula IV, R₁And R₂Are each independently a hydrogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; a methyl chloride group and a trifluoromethyl group And the like, and preferably represents a methyl group, a methoxy group, or a trifluoromethyl group independently of each other.
Specific examples of the bisstyrylbenzene-based fluorescent dye are shown below.
[0027]
Embedded image

[0028]
(V) Oxazole fluorescent dye
The dye is represented by the following general formula V.
Embedded image

In the general formula V, X and Y are each independently a hydrogen atom; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; and a C1 to 6 carbon atom such as a methyl chloride group and a trifluoromethyl group. Represents a halogenated alkyl group, preferably, independently of each other, a hydrogen atom, a methoxy group, or a trifluoromethyl group.
Specific examples of the oxazole-based fluorescent dye are shown below.
[0029]
Embedded image

[0030]
(VI) Europium complex fluorescent dye
The dye is represented by the following general formula VI.
Embedded image

In the general formula, R₁And R₂Represents, independently of each other, a hydrogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group. A hydrogen atom, a methyl group, and a methoxy group are independently represented. R₃~ R₅Each independently represents a chain alkyl group or a cyclic alkyl group having 4 or more carbon atoms, and among these, preferably independently of each other, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group or the like having 4 to 4 carbon atoms. 8 represents an alkyl group.
Specific examples of the europium complex fluorescent dye are shown below.
[0031]
Embedded image

[0032]
In the present invention, the fluorescent dye used for forming the color material layer is selected from the above-described fluorescent dyes. At this time, compatibility and solubility with the binder and the organic solvent constituting the color material layer, and further, coating It is selected in consideration of properties and the like, and usually, a fluorescent dye that dissolves in methyl ethyl ketone at least 5% by weight is preferable.
[0033]
The binder component used in the color material layer is not particularly limited, and is appropriately selected from binder resins usually used for a color material ribbon for sublimation type thermal transfer. Specifically, polycarbonate resin, polysulfone resin, polyvinyl butyral resin, polyacetal resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer resin, polyarylate resin, polyamide resin, polyimide resin, polyetherimide resin, polyester resin, Binder resins such as acrylonitrile-styrene copolymer resins and cellulosic resins are exemplified. Among these, a polyvinyl butyral resin, a polyacetal resin, and a vinyl chloride-vinyl acetate copolymer resin are preferable in terms of compatibility with the fluorescent dye.
[0034]
It is preferable that the coloring material layer containing the fluorescent dye of the present invention contains a stabilizer for the purpose of suppressing the decomposition of the fluorescent dye due to long-term storage. The stabilizer is desirably one that transfers with the transfer of the fluorescent dye to the dyeing layer (receiving layer) of the material to be transferred during sublimation thermal transfer, and is not particularly limited as long as such a property is satisfied. The stabilizer can be appropriately selected from commercially available products in consideration of coatability and the like according to components constituting the color material layer such as a fluorescent dye, a binder resin, a solvent, and other additives. And a hindered phenol-based stabilizer. Specific examples of these stabilizers are shown below.
[0035]
Embedded image

[0036]
The coloring material layer of the present invention further contains a lubricating component such as a silicone resin, amino-modified or ether-modified, in order to improve the releasability between the coloring material ribbon and the dyed layer of the material to be transferred after the sublimation thermal transfer printing. A modified silicone resin, a silicone-modified acrylic resin, or the like may be added.
Further, in the coloring material ribbon of the present invention, an easy-adhesion layer may be provided between the base material and the coloring material layer in order to strengthen the adhesion between the base material and the coloring material layer. The material for forming the easily adhesive layer is not particularly limited, and examples thereof include a polyurethane resin and a methamine resin.
[0037]
Regarding the ratio of the fluorescent dye, the binder component, the stabilizer and other components in the color material layer, the fluorescent dye is usually 0.5 to 90 parts by weight, preferably 0.5 to 70 parts by weight with respect to 100 parts by weight of the binder component. And usually 0.3 to 80 parts by weight, preferably 0.3 to 50 parts by weight, based on 100 parts by weight of the total amount of other components. The amount of the stabilizer is usually 15 to 60 parts by weight, preferably 15 to 30 parts by weight, based on 100 parts by weight of the binder component. If the amount of the fluorescent dye or the stabilizer exceeds the above range, and if the amount is too large, precipitates are likely to be formed on the surface of the color material ribbon, and the fusion of the color material ribbon and the dyed layer of the material to be transferred under sublimation thermal transfer conditions. Is likely to occur, which is not preferable.
[0038]
The method for forming the coloring material layer on the coloring material ribbon for fluorescent printing of the present invention on the substrate is not particularly limited, and for example, the above-described fluorescent dye, binder resin, stabilizer and other components added as necessary It can be formed by preparing a coating solution dissolved or dispersed in a suitable solvent, applying the coating solution to a base film of a substrate, and then drying.
Examples of the solvent include chlorinated alkane solvents such as chloroform, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and cyclohexanone, alcohol solvents such as ethanol and isopropanol, and ether solvents such as dioxane and tetrahydrofuran. Solvents, amide solvents such as N-methylpyrrolidone, dimethylformamide and the like, and these may be used alone or as a mixture.
[0039]
Each color material layer containing each of the R, G, and B fluorescent dyes may be a ribbon for each color provided on a separate base material, or each color material layer of R, G, and B may be provided on the same base material. It can also be provided in a plane sequence. In this case, it is also possible to form a pattern together with a UV blocking image protective layer or a visible sublimation thermal transfer color material layer, which will be described later, or to arrange them face-to-face.
[0040]
In the present invention, using a normal sublimation thermal transfer printer, the color material layer surface of the color material ribbon and the dyed layer of the material to be transferred are overlapped, and the back surface (the surface opposite to the color material layer) of the color material ribbon is heated with a thermal head. By heating, the sublimation heat transferable fluorescent dye is transferred to the dyeing layer, and a full-color image is printed on the transfer material.
As the material to be transferred, a sublimation thermal transfer fluorescent dye having a dyeing surface (dye layer) that can be dyed by heat transfer from the color material ribbon during sublimation thermal transfer printing is used. In addition, receivers used in conventional sublimation thermal printing media can also be used.
[0041]
The transfer material usually has a dyeing layer on a substrate, and the dyeing layer contains a binder component, a releasability-imparting substance, and the like. The binder component is not particularly limited, and examples thereof include a vinyl chloride-vinyl acetate copolymer resin, a polyester resin, a polyvinyl acetal resin, and a mixed resin thereof.Examples of the release-imparting material include silicone oil, Modified silicone oil and the like can be mentioned. The thickness of the dyeing layer is usually from 1 to 10 μm, preferably from 3 to 5 μm.
The substrate is not particularly limited, and examples thereof include a core material (for example, paper, a polyester resin such as polyethylene terephthalate (PET), preferably paper) and a porous resin material bonded to both surfaces. Examples of the porous resin material include porous polypropylene and PET sheets, and a porous polypropylene sheet is preferable. The thickness of the core material is 50 to 150 μm (50 to 150 g / m²), Preferably 80 to 120 µm (80 to 120 g / m²), And the thickness of the porous resin material is 20 to 100 μm, preferably 40 to 80 μm.
[0042]
In the sublimation thermal transfer, usually, the R, G, B primary color light additive mixed positive image signal (see FIG. 1) is converted into a Y, M, C reduced color mixed image signal inside the sublimation thermal transfer printer. Perform printing. In the present invention, in order to perform fluorescent image printing by sublimation thermal transfer, an image in which R, G, and B three primary color light-added mixed negative image signals (see FIG. 2) are replaced with CYM intensities of RGB in complementary colors. By inputting as a signal and printing with green (G) replaced with Y, blue (B) replaced with M, and red (R) replaced with C, a full-color fluorescence-added mixed luminescence image by sublimation thermal transfer is obtained as a result. Can be obtained.
[0043]
In the present invention, an ultraviolet blocking image protective layer that absorbs ultraviolet light of a specific wavelength is placed on a full-color fluorescent light-emitting image formed by sublimation thermal transfer printing, and the ultraviolet fluorescent light emission of the image is controlled.
The fluorescent dye emits light with black light, and its excitation absorption (the absorbed light is emitted as visible fluorescence) is usually in the range of 250 to 400 nm. Depending on the wavelength of the excitation light, its maximum absorption wavelength, absorption efficiency, absorption The shape of the spectrum is different. That is, by changing the wavelength of the irradiation light with respect to the fluorescent light emitting image, the pattern of the ultraviolet fluorescent light emission can be changed, and a full-color image having a different color tone can be displayed.
[0044]
By covering the full-color image formed by the fluorescent dye with an ultraviolet blocking image protection layer that absorbs ultraviolet light of a specific wavelength, even if the irradiation light is within the same ultraviolet region, the irradiation light of the specific wavelength is absorbed and absorbed by the protection layer. Since the light is cut off, the fluorescent light emission pattern of the image differs when the specific wavelength light and the wavelength different from the specific wavelength are irradiated. In addition, when there is no protective layer, or when a modification is made to the printed matter due to modification or the like, a change occurs in the protective layer, the UV-blocking image protective layer changes, and the mode of absorbing ultraviolet light of a specific wavelength changes, and light of a specific wavelength is used. The resulting color tone of the fluorescent image will also change. By utilizing such a difference between the fluorescent light emission images caused by a difference in the wavelength of the irradiation light or a difference in the state of the protective layer, it is possible to determine whether the full-color image is authentic or not.
[0045]
That is, at least one kind of fluorescent light emission pattern generated by blocking ultraviolet rays of a specific wavelength, in particular, a color tone is set in advance. For this purpose, the type of fluorescent dye to be used, the dye concentration in the coloring material, the wavelength of the black light to emit fluorescent light, the protection For the combination of various elements such as the type and concentration of the ultraviolet absorber in the layer, an optimal combination is experimentally selected. If the fluorescent light-emitting printed material constituted by this combination is a genuine product, if the printed material of the inspection object is irradiated with irradiation light of a specific wavelength (corresponding to inspection light), if the fluorescent light-emitting pattern is different from the genuine fluorescent light-emitting pattern, , The thing is determined to be fake. In this case, if the irradiation light of two kinds of wavelengths is used as the specific wavelength of the fluorescence emission pattern set in advance, it is possible to identify the forgery with higher accuracy, and the two kinds of wavelengths are black light. It is advantageous to use commonly used long waves (365 nm) and short waves (254 nm).
[0046]
For example, in the case of an image in which an original face photograph (white background) is printed in full color with a fluorescent dye by sublimation thermal transfer according to the present invention and covered with an ultraviolet ray blocking image protective layer, a W portion (three-dimensional background of the photograph) where three screens are overprinted ) Is colorless under visible light and does not change from the ground color, but emits white light (set to white light emission) when the W portion is irradiated with a long wave of black light (365 nm). On the other hand, when the same long wave (365 nm) is irradiated to the printed matter to be inspected, if the white light is not emitted or the emitted light is not white, the printed matter is determined to be a counterfeit product.
Also, by changing the combination of the fluorescent dye and the ultraviolet absorber of the protective layer, white light emission (set to white light emission) for long wave irradiation, but changing the gray balance (short white light) for short wave (254 nm) irradiation. It can also be set to emit light with a specific color tone (color). Therefore, if the fluorescent light emission pattern is set for such two types of irradiation light of a specific wavelength, when the print object to be inspected is irradiated with two kinds of different wavelengths of light, the light emission pattern by both irradiation lights is of course. If the fluorescent pattern is different from the preset light emitting pattern due to at least one of the irradiation lights, the printed matter is determined to be a fake.
[0047]
The present invention is a full-color fluorescence emission image unlike the conventional single-color fluorescence emission image, and includes the type and concentration of the fluorescent dye in the color material layer, the type and concentration of the ultraviolet absorber in the protective layer, the wavelength of the irradiation light, and the like. Since the fluorescent light emission pattern can be variously changed by arbitrarily combining the various elements described above, it is extremely difficult to analyze the expression element of the preset fluorescent light emission pattern. Therefore, it is very difficult to manufacture a counterfeit of the fluorescent printed matter of the present invention, and it can be said that the printed matter has a very high anti-counterfeiting effect.
In addition, a visible image (reference image) printed with a sublimation thermal transferable dye recognizable by visible light is printed on the same image receiving paper as a non-visible image with a fluorescent dye that emits fluorescent light in a predetermined color tone. The authenticity can also be determined based on the deviation from the reference image due to the light irradiation.
Further, in the present invention, the light resistance can be improved by covering the full-color image by the fluorescent light emission with the ultraviolet ray shielding image protective layer.
[0048]
The ultraviolet-blocking image protective layer contains an ultraviolet absorber and a binder, and it is necessary to select an ultraviolet absorber suitable for absorbing ultraviolet light of a specific wavelength and controlling the ultraviolet fluorescent emission of an image. That is, assuming a fluorescence emission pattern when irradiating light of a specific wavelength set in advance, the type of the fluorescent dye to be used, the absorption spectrum, the wavelength of the irradiation light, and further consider the behavior such as coloring under visible light, The UV absorber is selected so as to produce a desired fluorescent emission pattern.
The ultraviolet absorber is not particularly limited as long as it satisfies such a function, but is usually selected from a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and the like. It is convenient to select these ultraviolet absorbers from commercially available products in terms of availability and cost. It is desirable that the UV absorber itself does not decompose even when exposed to UV light and has a high UV absorption efficiency.
[0049]
Specific examples of the benzotriazole-based ultraviolet absorber include the following compounds.
Embedded image

[0050]
In addition, specific examples of the triazine-based ultraviolet absorber and the benzophenone-based ultraviolet absorber include the following compounds.
Embedded image

[0051]
The binder contained in the ultraviolet ray blocking image protective layer is not particularly limited, and usually includes a polyester resin, a vinyl chloride-vinyl acetate copolymer resin, an epoxy resin, and a mixed resin thereof.
[0052]
The amount of the ultraviolet absorber is usually 1 to 30 parts by weight, preferably 2 to 25 parts by weight, based on 100 parts by weight of the binder resin. If the amount of the UV absorber used is too large, poor fusion between the fluorescent printed image and the UV blocking image protective layer is likely to occur, which is not preferable.
The thickness of the ultraviolet light shielding image protective layer covering the fluorescent print image is usually 0.2 to 2 μm, preferably 0.5 to 1.5 μm.
[0053]
The method of covering the fluorescent printed image is not particularly limited, and can be performed by any method that can adhere the ultraviolet light shielding image protective layer on the fluorescent printed image, for example, provided on the base film of the base material. The UV-blocking image protective layer containing the UV-absorbing agent and the binder is superimposed on the fluorescent-printed image surface, and heated from the back side of the base fill having no UV-blocking image protective layer with a thermal head or the like. The protective layer can be coated on the image by bonding and fusing. In that case, in order to facilitate heating from the back side, it is preferable that the base film is provided with a back layer that enables a smooth transfer of a thermal head or the like, and that the protective layer is provided via a release layer. A protective layer may be formed on the film and peeling off the release layer after the coating is completed.
[0054]
Formation of the ultraviolet blocking image protective layer on the substrate is performed by a conventional method, for example, a coating solution is prepared by dissolving a binder and an ultraviolet absorber in an arbitrary solvent, and a gravure coater, a kiss coater, a reverse coater, It is formed by applying and drying a coating solution on a release layer on a substrate having a release layer on one side and a back layer on the other side in advance using a usual coating method such as a bar coater. The solvent is not particularly limited as long as it dissolves an ultraviolet absorber and a binder, and aromatic hydrocarbon solvents such as toluene and xylene; halogenated alkyl organic solvents such as chloroform; ketone organic solvents such as methyl ethyl ketone; These mixtures are appropriately used.
[0055]
As the substrate, a polyethylene terephthalate film or the like having a thickness of about 3 to 15 μm is used, and the back layer is made of the same material as that applied to a normal sublimation thermal transfer color material ribbon such as a modified silicone compound. used. Further, a commercially available polyester film or the like to which releasability has been imparted may be used, and an ultraviolet-shielding image protective layer may be provided thereon.
As the formation of the release layer on the base material and the material of the release layer, conventionally known methods and materials can be used. For example, homopolymers, copolymers or mixtures thereof such as acrylic resins, vinyl chloride resins, cellulose resins, rubber resins, urethane resins, polyester resins, vinyl acetate resins, ethylene-vinyl acetate resins, etc. An organic solvent solution or dispersion obtained by adding a silicone resin, a silicone graft acrylic resin, a silicone graft / polyester resin, etc. as a release controlling agent according to a known coating method, for example, a gravure method, a silk screen printing method, and a roll coater. In general, it can be formed by applying a dry film thickness of 0.1 μm or more and 2 μm or less by a method, a spray coating method, a flow coating method, a knife coating method, an air knife coating method, and the like, and drying by heating. I can do it.
[0056]
In the present invention, the fluorescent printed image is formed on the dyeing layer of the material to be transferred by sublimation thermal transfer printing using a coloring material ribbon having a coloring material layer containing a sublimation thermal transferable fluorescent dye, so that the image is coated. An ultraviolet protection image protective layer can be provided on the same surface as the color material layer of the color material ribbon in a face-to-face manner, whereby the protective layer can be formed thereon after image formation by thermal transfer.
[0057]
Further, in the present invention, since an image is formed by a sublimation thermal transfer printing method, a color material having a coloring material layer containing a fluorescent dye that emits fluorescence (invisible sublimation thermal transferable coloring material layer) and an ultraviolet ray blocking image protection layer Printing a visible image and a fluorescent light-emitting image on the same transfer material by coexisting a color material layer containing a sublimation thermal transfer dye that can be recognized with visible light (visible sublimation thermal transfer color material layer) on the ribbon It allows you to That is, the same sublimation thermal transfer printer can be used to place a fine fluorescent image that is difficult to forge and a visible sublimation thermal transfer image for reference (hereinafter, also referred to as a normal image) on the dyeing layer of a single material to be transferred. It can be formed in a pattern.
As an example of providing such an invisible sublimation thermal transfer color material layer and a visible sublimation thermal transfer color material layer on a single color material ribbon, as shown in FIG. 3 and FIG. And B, the invisible sublimation heat transferable color material layer and the visible sublimation heat transfer color material layer can be provided in series in the longitudinal direction of the ribbon, or can be provided in parallel.
[0058]
A normal R, G, B image signal and an R, G, B negative image signal are combined and sent to a sublimation thermal transfer printer. For example, if a color material ribbon of the type shown in FIG. The image and the fluorescent image can be formed on a single dyeing layer. When a color material ribbon of the type shown in FIG. 4 is used, a normal image and a fluorescent image can be formed adjacently on a single dyeing layer.
[0059]
Further, the coloring material ribbon of the present invention is provided with an ultraviolet shielding image protective layer together with the coloring material layer, and after forming a fluorescent image and a normal image by sublimation thermal transfer, these images are thermally transferred by the protective layer. Can be coated. The protective layer contains an ultraviolet absorber that absorbs ultraviolet light of a specific wavelength and controls ultraviolet fluorescent emission of a fluorescent image. Can serve as a protective layer. As a result, the light resistance of the printed image can be improved.
[0060]
As is usually performed in sublimation thermal transfer printing, a fluorescent image is formed on a dyeing layer provided on a transparent substrate by a method of the present invention together with a normal image, if necessary, and then covered with an ultraviolet light shielding image protective layer. After attaching an image to a second substrate or forming an image on a releasable dyeing layer and covering with an ultraviolet ray blocking image protective layer, attaching the separated dyeing layer to the second substrate Can also be.
[0061]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.
[0062]
[Reference example]
(I) Coating test of fluorescent dye, stabilizer and UV absorber
1.Measurement of maximum absorption wavelength and maximum fluorescence wavelength
Each of the aforementioned fluorescent dyes (Nos. 1-34) was dissolved in ethanol,^-5As a mol / L solution, the maximum absorption wavelength and the maximum fluorescence wavelength were measured with a Hitachi F-4500 type ultraviolet spectrometer. The results are shown in Table 1 together with the types of emission colors (blue, green, and red). In Table 1, No. Is the fluorescent dye number. As a result, it can be seen that the maximum wavelength is distributed at 340 to 395 nm.
[0063]
[Table 1]

[0064]
2.Test for confirming coating properties of colorant layer coating solution
In order to confirm the presence or absence of a precipitate when the color material layer was formed on the color material ribbon, a coating test was performed using a dye and a stabilizer having the following composition. In addition, No. of a dye and a stabilizer Is the same as the compound No.
Table 2-Fluorescent dye mixture
(B, G, and R represent the emission colors of blue, green, and red, respectively)
[Table 2]

[0065]
[Table 3]

[0066]
The above-mentioned dye mixture, stabilizer mixture, and acetal resin (KS-5; manufactured by Sekisui Chemical Co., Ltd.) as a binder were used in the composition ratio shown in Table 4, and dissolved in 2000 parts of chloroform to prepare a coating solution. This coating solution was applied on a polyethylene terephthalate (PET) film using a Meyer bar, and then dried in an oven at 110 ° C. for 30 seconds to form a 1.0 μm coating layer. The surface of the coating layer was visually observed, and the presence or absence of a precipitate causing fusion of the colorant ribbon and the image receiving layer during heating printing was examined. Table 4 shows the results.
[0067]
[Table 4]

[0068]
3.Confirmation test of coating properties on UV blocking image protective layer coating solution
A test was performed to confirm that no precipitate such as an ultraviolet absorber was generated from the protective layer when the protective layer was formed by coating, using the ultraviolet absorber mixture described in Table 5. In addition, compound No. of an ultraviolet absorber. Is the compound No. Is the same as
[Table 5]

[0069]
The UV stabilizer mixture and an acrylic resin (Paraloid {A-21}; manufactured by Rohm and Haas Co.) as a binder were used in the composition ratios shown in Table 6, and dissolved in a mixed solvent of 500 parts of toluene and 500 parts of methyl ethyl ketone to form a coating solution. Was prepared. This coating solution was applied on a PET film using a Meyer bar, and then dried in an oven at 110 ° C. for 30 seconds to form a 1.0 μm coating layer. The surface of the coating layer was visually observed, and the presence or absence of precipitates which caused the poor adhesion between the heated print and the protective layer was examined. The results are shown in Table 6. As a result, it is found that the amount of the ultraviolet absorber is 30 parts or less, preferably 25 parts or less based on the binder resin.
[0070]
[Table 6]

[0071]
(II) Preparation of ribbon for thermal transfer
1. Preparation of base material with heat-resistant lubricating layer
A PET film (K233E6.5W; manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material of a ribbon with a fluorescent dye-containing coloring material layer, and a peelable PET film (AS12; Mitsubishi Polyester Film) is used as a base material of a ribbon with an ultraviolet ray blocking image protective layer. Was used. A coating solution having the following composition was applied to one surface of the PET film and the untreated surface of the peelable PET film using a Meyer bar, and then dried in an oven at 115 ° C. for 45 seconds to form a 1.2 μm heat-resistant slip layer. To form a PET substrate.
[0072]
Heat-resistant lubricating layer coating liquid formulation
Taiyanal LR-313 (acrylic resin; manufactured by Mitsubishi Rayon Co.) 80 parts
M-1002B (acrylic resin; manufactured by Soken Chemical Co., Ltd.) 20 parts
BY16-892 {Amino-modified silicone oil; manufactured by Torayta Ukonink Co., Ltd.}
KP0101 (Amino-modified silicone oil; Shin-Etsu Chemical Co., Ltd.) 3 parts
X-22-3701E (Carboxy modified silicone oil; Shin-Etsu Chemical Co., Ltd.)
MX-180 (spherical acrylic resin; manufactured by Soken Chemical Co., Ltd.)
Toluene 300 parts
Methyl ethyl ketone 200 parts
[0073]
2. Preparation of ribbon with colorant layer containing fluorescent dye
The fluorescent material, the stabilizer mixture and the acetal resin (KS-5; manufactured by Sekisui Chemical Co., Ltd.) shown in Tables 2 and 3 are used in the composition ratio shown in Table 7 and dissolved in 2,000 parts of chloroform to form a colorant layer. A coating solution was prepared. This coating solution was applied to the non-slip layer surface of the ordinary PET film with a heat-resistant slip layer prepared in 1 above using a Meyer bar, and then dried in an oven at 110 ° C. for 30 seconds to form a 1.0 μm color material layer. Various ribbons of each fluorescent color with were made.
[0074]
Table 7 Fluorescent color material ribbon
[Table 7]

[0075]
3. Preparation of ribbon with UV protection image protection layer
An ultraviolet absorbent and an acrylic resin (Paraloid {A-21}; manufactured by Rohm and Haas Co.) shown in Table 8 were used in the composition ratio shown in Table 7, and dissolved in a mixed solvent of 500 parts of toluene and 500 parts of methyl ethyl ketone to form a coating solution. Was prepared. This coating solution is applied to the peelable surface of the peelable PET film with a heat-resistant slip layer prepared in 1 above using a Meyer bar, and then dried in an oven at 110 ° C. for 30 seconds to have a 1.0 μm coating layer. A ribbon with a protective layer was made. The UV spectrum of the ribbon with the protective layer was measured using a Hitachi F-4500 UV spectrometer, and the wavelength at which the transmittance became 50% or less was defined as the cutoff wavelength. Table 8 shows the results.
[0076]
[Table 8]

[0077]
4. Preparation of receiving paper with dyeing layer
Coated paper (108g / m²)), On the one side of a substrate obtained by applying an adhesive resin layer on both sides and laminating a foamed polypropylene film (thickness: 50 μm), using a Meyer bar, apply the following dyeing layer coating solution to a dry coating thickness of 4 μm. And then dried. After drying, aging was performed at 45 ° C. for one week to obtain an image receiving paper. The ground color of the image receiving paper is white.
Dyeing layer coating solution
Polyvinyl phenyl acetal 10.0 parts
Vinyl chloride-vinyl acetate copolymer resin 10.0 parts
Silicone oil 2.0 parts
Isocyanate 3.0 parts
Methyl ethyl ketone 2.0 parts
Toluene 3.0 parts
[0078]
[Examples, Comparative Examples, Reference Examples]
1. Sublimation thermal transfer printing
Using a commercially available sublimation thermal transfer printing printer (NV-AP1; Matsushita Electric Industrial Co., Ltd.), an overcoat type ink ribbon (VW-APLC36; Matsushita Electric Industrial Co., Ltd.) yellow screen and magenta screen for the printer. And the cyan screen and the protective layer screen are cut out, respectively, and the blue (B) fluorescent ribbon, the green (G) fluorescent ribbon and the red (R) fluorescent ribbon prepared in (II) 2 and 3 above, and the ultraviolet light shielding are cut off. The image protection layer ribbon was connected in this order to the cut portion to form a print ribbon. As the image receiving paper, the image receiving paper prepared in the above (II) 4 was cut into the same size as that for the printer and used, and the printing was performed using a negative image (FIG. 2) so that the image shown in FIG. The data was input and printed to obtain a fluorescent latent image image. Table 9 summarizes the combinations of the coloring material ribbon and the ultraviolet ray blocking image protective layer ribbon in each printing test, and the results of the following fluorescent image evaluation tests.
[0079]
2. Fluorescence image evaluation test
a) Whiteness (W part image whiteness)
The whiteness of the W portion on which three screens are overprinted was measured with a color difference meter (SZ- # 90; manufactured by Nippon Denshoku) according to JIS-P8123. If the whiteness under visible light is 75% or more, the image is considered to be sufficiently white, so that in this test using white receiving paper, it is judged that the image is almost the same as the ground color.
[0080]
b) Luminescence test
The light emission state of the W portion image was observed by irradiation with black light (UVGL-25; Funakoshi).
b-1: Black light irradiation W part color development (long wave)
It was confirmed that red, blue, and green colors were emitted by long-wave (365 nm) ultraviolet irradiation, and that the W portion where three screens were overprinted emitted white light (white light emission).
b-2: Black light irradiation W part coloring (short wave)
By irradiation with short wave (254 nm) ultraviolet rays, a change in the color development state (white to tint) of the W portion, that is, a change in the gray balance was observed.
[0081]
c) Light fastness test (color development of W part after fade test)
In accordance with JIS-L0843, after irradiating light with a xenon fade meter for 1 hour and 3 hours, it was confirmed whether or not there was coloring of an image by irradiating with a long wave (365 nm) ultraviolet light with a black light. One hour of xenon irradiation is considered to have been exposed under an indoor fluorescent lamp for about 1 month, and if it develops under these conditions, it is considered that there is no problem in normal use. However, when exposed under an indoor fluorescent lamp for about 3 months. It is more desirable to develop color even with xenon irradiation for 3 hours.
[0082]
Table 9 Printing and Evaluation Results
[Table 9]

[0083]
The results of the above Examples and Comparative Examples show the following.
1) The whiteness of the fluorescent image obtained by the present invention is 75% or more, and there is substantially no difference from the ground color, and an image in an excellent latent image state can be obtained.
2) As is clear from the reference example and Example 1, light is not emitted when the cutoff wavelength of the ultraviolet blocking protective layer is 400 nm or more. Therefore, when selecting the ultraviolet absorber for the protective layer, care should be taken that the cutoff wavelength is less than 400 nm. However, when the cutoff wavelength is 280 nm or less, it is necessary to select a stabilizer in consideration of light resistance.
3) Although the light fastness is improved by providing the ultraviolet blocking protective layer (Example 5 and Comparative Example 3), it is clear that the addition of a stabilizer to the coloring material layer further improves the light fastness of the fluorescent image (Execution) Example 5 and Example 8).
4) The fluorescent dye contained in the color material layer may be used alone or in combination of two or more (Examples 9 and 10).
5) Even if the same UV blocking protective layer is the same, the combination of each color material ribbon is changed, or the combination of the same color material ribbon is combined with the UV blocking protective layer having a different cutoff wavelength to change the gray balance (white (A change in emission from light emission).
6) Even in the ultraviolet blocking protective layer having the same cutoff wavelength, a change in gray balance by short wave irradiation occurs due to a difference in the type and blending ratio of the ultraviolet absorber contained in the protective layer (Examples 25 to 29).
[0084]
【The invention's effect】
According to the present invention, a full-color image formed by sublimation thermal printing using a sublimation thermal transferable fluorescent dye is covered with an ultraviolet-blocking image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling ultraviolet fluorescent emission of the image. In addition, it is possible to change the color tone of the fluorescent light emission image due to the irradiation of the specific wavelength light. Therefore, the emission of a full-color image coated with the protective layer obtained in the present invention can be controlled in a complicated manner by a combination of a protective layer, a fluorescent dye, and an irradiation wavelength. In addition, the protective layer has light resistance that can withstand practical use. Therefore, the fluorescent light-emitting printed matter obtained by the present invention can be used for various certificates and securities excellent in forgery prevention. Furthermore, the present invention can provide a color material ribbon for sublimation thermal transfer printing suitable for obtaining such a fluorescent light-emitting printed material, and therefore has high industrial value.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing the principle of red (R), green (G), and blue (B) three primary color light-added mixed positive images.
FIG. 2 is an explanatory diagram showing the principle of a red (R), green (G), and blue (B) three primary color light subtractive mixed negative image.
FIG. 3 is an explanatory view of a coloring material ribbon in which a visible sublimation thermal transferable color material layer region and an invisible sublimation thermal transferable fluorescent color material layer region are provided in series in the longitudinal direction of the ribbon.
FIG. 4 is an explanatory diagram of a color material ribbon in which a visible sublimation thermal transfer color material layer region and an invisible sublimation thermal transfer fluorescent color material layer region are provided in parallel in the longitudinal direction of the ribbon.

Claims (27)

An image forming material for fluorescent printing, having a color material layer of each color including at least one of red (R), green (G) and blue (B) sublimation thermal transfer fluorescent dyes and a binder component on a substrate. A method for producing a fluorescent light-emitting printed matter, comprising: coating a full-color image printed by sublimation thermal transfer printing with an ultraviolet-shielding image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling the ultraviolet fluorescent light emission of the image. . 2. The method according to claim 1, wherein the ultraviolet-shielding image protective layer has a transmittance of light having a specific wavelength in an ultraviolet region of 50% or less. The method according to claim 1 or 2, wherein the wavelength of the specific wavelength light in the ultraviolet region is 280 nm or more and less than 400 nm. The fluorescent material according to any one of claims 1 to 3, wherein the color material layer of each color of the image forming material contains at least one stabilizer selected from a hindered amine-based material and a hindered phenol-based material. Manufacturing method of printed matter. The ultraviolet-blocking image protective layer contains at least one ultraviolet absorber selected from the group consisting of benzotriazole-based, triazine-based and benzophenone-based, according to any one of claims 1 to 4, wherein A method for producing a fluorescent light-emitting printed matter. The fluorescent emission according to any one of claims 1 to 5, wherein the sublimation thermal transfer fluorescent dye of R, G and B has a maximum absorption wavelength in a range of 340 to 395 nm (in ethanol). Manufacturing method of printed matter. The sublimation thermal transfer fluorescent dyes of R, G and B are at least one selected from thiophene-based, β-quinophthalone-based, coumarin-based, bisstyrylbenzene-based, oxazole-based and europium complex-based sublimation-sensitive heat-transferable fluorescent dyes, respectively. The method for producing a fluorescent light-emitting printed matter according to any one of claims 1 to 6, wherein the carbon atom system forming a conjugated system in the molecule is a dye having no side chain conjugated system. . The method for producing a fluorescent light-emitting printed matter according to any one of claims 1 to 7, wherein the thiophene-based sublimation thermal transfer fluorescent dye is represented by the following general formula (I).

(Wherein, R independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms). The method according to any one of claims 1 to 7, wherein the β-quinophthalone-based sublimation heat transferable fluorescent dye is represented by the following general formula II.

(In the formula, X represents a hydrogen atom, a halogen atom, an aryl group which may have a substituent, Y represents a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, Z is a hydrogen atom, a 1 to 1 carbon atom. 6 represents a halogenated alkyl group or an alkoxy group having 1 to 6 carbon atoms.) The method according to any one of claims 1 to 7, wherein the coumarin-based sublimation thermal transfer fluorescent dye is represented by the following general formula III.

(Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group which may have a substituent, and X and Y each independently represent a hydrogen atom, Represents an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group having 1 to 6 carbon atoms.) The method for producing a fluorescent light-emitting printed matter according to any one of claims 1 to 7, wherein the bisstyrylbenzene-based sublimation thermal transfer fluorescent dye is represented by the following general formula IV.

(In the formula, R ₁ and R ₂ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogenated alkyl group having 1 to 6 carbon atoms. ) The method according to any one of claims 1 to 7, wherein the oxazole-based sublimation thermal transfer fluorescent dye is represented by the following general formula V.

(In the formula, X and Y independently represent a hydrogen atom, an alkoxy group having 1 to 6 carbon atoms, or a halogenated alkyl group having 1 to 6 carbon atoms.) The method for producing a fluorescent light-emitting printed material according to any one of claims 1 to 7, wherein the europium complex-based sublimation thermal transfer fluorescent dye is represented by the following general formula VI.

(Wherein, R ₁ and R ₂ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and R _{3 to} R ₅ each independently represent It represents a chain alkyl group or a cyclic alkyl group having 4 or more carbon atoms.) The image forming material is provided with a color material layer of each color including a sublimation thermal transfer fluorescent dye of R, G and B and an ultraviolet ray blocking image protective layer on a substrate in a plane-sequential manner. Item 14. The method for producing a fluorescent light-emitting printed matter according to any one of Items 1 to 13. In the image forming material, R, G and B sublimation heat transfer colorants that can be further recognized by visible light in a color material layer of each color containing R, G and B sublimation heat transfer fluorescent dyes on a substrate. The method for producing a fluorescent light-emitting printed matter according to claim 14, wherein color material layers of each color including A full-color image formed by sublimation thermal transfer printing using a fluorescent printing image forming material having at least one of R, G, and B sublimation thermal transferable fluorescent dyes and a color material layer of each color containing a binder on a substrate. A fluorescent light-emitting printed material, which is coated with an ultraviolet-shielding image protective layer capable of absorbing ultraviolet light of a specific wavelength and controlling ultraviolet fluorescent light emission of the image. 15. A fluorescent light-emitting printed material comprising a full-color image printed by sublimation thermal transfer using the image forming material according to claim 14 and covered with an ultraviolet shielding image protective layer by thermal transfer. 16. A fluorescent light-emitting printed material, comprising a fluorescent light-emitting full-color image printed by sublimation thermal transfer and a full-color image recognizable by visible light using the image forming material according to claim 15 covered with an ultraviolet ray blocking image protective layer by thermal transfer. A color material comprising a color material layer containing a sublimation thermal transfer fluorescent dye of R, G and B and a color material layer containing a sublimation thermal transfer colorant of R, G and B recognizable by visible light on a substrate An image forming material comprising a layer region and an ultraviolet-blocking image protective layer region capable of absorbing ultraviolet light of a specific wavelength and controlling ultraviolet fluorescent light emission in a plane-sequential manner. 18. The image forming material according to claim 17, wherein the sublimation thermal transfer fluorescent dyes of R, G and B are selected from the dyes according to claim 7. 21. The coloring material layer containing the sublimation thermal transfer fluorescent dye of R, G and B contains at least one stabilizer selected from hindered amine-based and hindered phenol-based. Image forming material. 22. The ultraviolet protective image protective layer according to claim 19, wherein the protective layer contains at least one ultraviolet absorber selected from the group consisting of benzotriazole, triazine and benzophenone. Image forming material. In the color material region on the base material, a color material layer containing R, G and B sublimation heat transfer colorants recognizable by visible light and a color material layer containing R, G and B sublimation heat transfer fluorescent dyes Are provided in series in the longitudinal direction of the base ribbon, and the image forming material according to any one of claims 19 to 22. In the color material region on the base material, a color material layer containing R, G and B sublimation heat transfer colorants recognizable by visible light and a color material layer containing R, G and B sublimation heat transfer fluorescent dyes Are provided in parallel in the longitudinal direction of the base ribbon, and the image forming material according to any one of claims 19 to 23. 15. The color tone of a fluorescent image developed by irradiating at least one specific wavelength light in the ultraviolet region of 250 to 400 nm on a true image printed matter produced by the method according to any one of claims 1 to 14, and inspecting. Authenticity detection of an image printed matter characterized by collating the color tone of an image developed when the same image printed matter is irradiated with light having the same wavelength as the irradiation light, and determining the authenticity based on the compatibility between the two. Method. Claims: Two types of irradiation light, long wavelength light and short wavelength light, are used as specific wavelength light, and the color tone of images expressed by irradiation of each wavelength on a true image print and a test image print is collated. Item 29. The method for detecting the authenticity of an image printed matter according to Item 25. 27. The method according to claim 25, wherein ultraviolet light of 365 nm and / or 254 nm is used as the specific wavelength light.

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