JPH07210859A - Magnetic recording medium and its production - Google Patents
Magnetic recording medium and its productionInfo
- Publication number
- JPH07210859A JPH07210859A JP6011319A JP1131994A JPH07210859A JP H07210859 A JPH07210859 A JP H07210859A JP 6011319 A JP6011319 A JP 6011319A JP 1131994 A JP1131994 A JP 1131994A JP H07210859 A JPH07210859 A JP H07210859A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic layer
- layer
- recording medium
- medium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Credit Cards Or The Like (AREA)
- Paints Or Removers (AREA)
- Magnetic Record Carriers (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は磁気記録媒体に関するも
のであり、特に、金融、流通、交通、通信などの代金決
裁に用いられるなど高い機密性を求められる磁気カード
などに適用する磁気記録媒体に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium applied to a magnetic card or the like which is required to have high confidentiality such as used for payment decision of finance, distribution, transportation, communication and the like. It is about.
【０００２】[0002]
【従来の技術】近年、金融・流通・交通・通信などの代
金決裁には磁気カードなどの磁気記録媒体が広く利用さ
れている。しかし、磁気カードなどは偽造やデータの改
ざんといった不正使用の危険にさらされており、特に代
金決裁など高い機密性を必要とする装置には、磁気記録
媒体自体により高い機密性を有するものが要求されてい
る。2. Description of the Related Art In recent years, magnetic recording media such as magnetic cards have been widely used for settlement of payment for finance, distribution, transportation, communications and the like. However, magnetic cards are at risk of unauthorized use such as forgery and falsification of data, and especially for devices that require high confidentiality such as payment approval, those with high confidentiality are required for the magnetic recording medium itself. Has been done.
【０００３】磁気記録媒体の機密性を高めるための手段
としては、通常の信号記録再生領域とは別に書き換えが
困難な媒体固有の識別情報を付与することが提案されて
いる。具体的には、特公昭４９−３７５２９号公報にあ
るように、針状磁性粉の磁化容易軸の配列方向を読み取
り方向に対して規則的に変化させて磁気パターンを設け
る方法や、特開昭５０−７９３１１号公報にあるよう
に、通常の磁性層に磁気記録された情報の磁界の作用下
に、磁性粒子を分散した磁性塗料を塗布して下層の情報
に支配された磁性粒子の配向を物理的に固定し、この固
定情報を識別に使用するとか、特開平５−３１８９７４
号公報にあるように、通常の磁性層に磁気記録された情
報を、その上に積層された保磁力が４５００エルステッ
ド以上の高保磁力の磁性粒子を有する磁性層に転写させ
ることにより、通常用いられる磁気ヘッドでは書換が困
難な情報を媒体に付与する方法などが知られている。As a means for increasing the secrecy of a magnetic recording medium, it has been proposed to provide medium-specific identification information that is difficult to rewrite in addition to the normal signal recording / reproducing area. Specifically, as disclosed in JP-B-49-37529, a method of providing a magnetic pattern by regularly changing the arrangement direction of the easy axis of magnetization of needle-like magnetic powder with respect to the reading direction, As disclosed in Japanese Patent Application Laid-Open No. 50-79311, a magnetic paint in which magnetic particles are dispersed is applied under the action of a magnetic field of information that is magnetically recorded on a normal magnetic layer to align the magnetic particles dominated by information in the lower layer. For example, it is physically fixed and this fixed information is used for identification.
As disclosed in Japanese Patent Laid-Open Publication No. JP-A-2003-187, it is usually used by transferring information magnetically recorded in an ordinary magnetic layer to a magnetic layer having thereon a high coercive force magnetic particle having a coercive force of 4500 Oersted or more. There is known a method of applying information that is difficult to rewrite with a magnetic head to a medium.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、針状磁
性粉の磁化容易軸の配列方向を読み取り方向に対して規
則的に変化させて磁気パターンを設ける方法は、読み取
りにあたって特殊な部品・装置を必要とし、更に製造す
るに際しても特殊な配向装置を必要とし、製造コストお
よび装置のコストがアップするという欠点を有してい
る。一方、高保磁力の磁性層に固有情報を転写する方法
では、特開昭５０−７９３１１号公報の方式では識別出
力が低い欠点がある。以下に述べるように、この欠点は
本発明により配向磁界を使用することにより解決される
ことを見出したが、同公報の方式では配向磁界は固定情
報の転写に有害な作用を及ぼすであろうと推定されたは
ずであるが意外にも良好な結果を与えるのである。また
特開平５−３１８９７４号の方法では、例えばＦｅ−Ｃ
ｏ合金のような飽和磁束密度が２２キロガウス程度の磁
性材料をコア材として作製した磁気ヘッドを使用すれ
ば、８０００エルステッド位までの高保磁力の磁性層は
十分書換が出来ることがよく知られており、しかも前述
した従来技術では、通常の磁性層よりも高保磁力の磁性
層の方が磁気ヘッドに接近した位置に配置されているた
めより強い磁界に晒されることになるので、固有情報を
書き換えることによる媒体の変造・偽造に対する危険性
が高いという問題点があった。また、この方式では、保
磁力が４５００Ｏｅ以上の磁性粒子を有する磁性層への
信号の転写は困難なだけでなく飽和磁化が低いために転
写信号の読取り出力が低い欠点がある。この欠点は本発
明により低保磁力の磁性粒子を使用することにより解決
されることを見出した。However, the method of providing the magnetic pattern by regularly changing the arrangement direction of the easy axis of magnetization of the needle-shaped magnetic powder with respect to the reading direction requires special parts and devices for reading. In addition, there is a drawback that a special aligning device is required for manufacturing and the manufacturing cost and the cost of the device are increased. On the other hand, in the method of transferring the unique information to the magnetic layer having a high coercive force, the method disclosed in Japanese Patent Laid-Open No. 50-79311 has a drawback that the identification output is low. As described below, it has been found that this drawback can be solved by using an orienting magnetic field according to the present invention, but it is presumed that the orienting magnetic field in the method of the publication will have a detrimental effect on the transfer of fixed information. It should have been done, but it gives surprisingly good results. In the method disclosed in JP-A-5-318974, for example, Fe-C
It is well known that if a magnetic head made of a magnetic material having a saturation magnetic flux density of about 22 kilogauss such as an o alloy is used as a core material, a magnetic layer having a high coercive force up to about 8000 Oersted can be sufficiently rewritten. Moreover, in the above-mentioned conventional technique, since the magnetic layer having a high coercive force is arranged closer to the magnetic head than the normal magnetic layer, the magnetic field is exposed to a stronger magnetic field. There is a problem that there is a high risk of the medium being altered or forged by the. In addition, this method has a drawback in that it is difficult to transfer a signal to a magnetic layer having magnetic particles having a coercive force of 4500 Oe or more, and read output of a transfer signal is low because saturation magnetization is low. It has been found according to the invention that this drawback is solved by using low coercivity magnetic particles.
【０００５】[0005]
【課題を解決するための手段】本発明は上記課題を解決
するために、非磁性基体の上の全体または一部に、２つ
以上の磁性層を積層してなる磁気記録媒体において、前
記磁性層の少なくとも１つの層をバインダ中に保磁力が
４０００Ｏｅ以下の強磁性粉末を分散して構成し、他の
磁性層に記録された信号による磁界並びに配向磁界の影
響により形成された、書換不能な固定信号が記録されて
いることを特徴とする磁気記録媒体を提供する。前記少
なくとも１つの層に記録された書換不能な固定信号は、
媒体を識別するための情報である。このような書換不能
な固定信号は、特定の領域における単位面積あたりの磁
気出力が隣接する他の領域と異なることにより記録され
ることができる。また、このような書換不能な固定信号
は、特定の領域における単位体積あたりの磁性粒子の含
有率が隣接する他の領域と異なることにより記録される
ことができる。In order to solve the above problems, the present invention provides a magnetic recording medium comprising two or more magnetic layers laminated on the whole or a part of a non-magnetic substrate. At least one of the layers is composed of a ferromagnetic powder having a coercive force of 4000 Oe or less dispersed in a binder, and is formed by the influence of a magnetic field due to a signal recorded in another magnetic layer and an orientation magnetic field. Provided is a magnetic recording medium having a fixed signal recorded therein. The non-rewritable fixed signal recorded on the at least one layer is
This is information for identifying the medium. Such a non-rewritable fixed signal can be recorded because the magnetic output per unit area in a specific area is different from that in another adjacent area. In addition, such a non-rewritable fixed signal can be recorded because the content rate of the magnetic particles per unit volume in a specific area is different from that in other adjacent areas.
【０００６】上記の書換不要な固定信号を有する記録媒
体は次のようにして製作することができる。すなわち、
非磁性基体の上の全体または一部に、少なくとも２つ以
上の磁性層を積層して磁気記録媒体を製造するに当た
り、少なくとも非磁性基体の上に第１の磁性層を塗布し
乾燥固化する工程、前記第１の磁性層に磁気記録手段に
よって媒体を識別するための情報を磁気記録する工程、
前記媒体を識別するための情報が磁気記録された第１の
磁性層の上にバインダ中に保磁力４０００Ｏｅ以下の強
磁性粒子を分散した磁性塗料を塗布して第２の磁性層を
形成する工程、前記第２の磁性層が乾燥固化する前に所
定の直流または交流磁界を印加することにより配向を行
う工程、及び前記配向された第２の磁性層を乾燥固化す
る工程を実行する。The above-mentioned recording medium having a fixed signal which does not require rewriting can be manufactured as follows. That is,
In manufacturing a magnetic recording medium by laminating at least two or more magnetic layers on the whole or a part of the non-magnetic substrate, a step of coating the first magnetic layer on at least the non-magnetic substrate and drying and solidifying Magnetically recording information for identifying a medium on the first magnetic layer by magnetic recording means,
A step of forming a second magnetic layer by applying a magnetic coating material in which ferromagnetic particles having a coercive force of 4000 Oe or less are dispersed in a binder on the first magnetic layer on which information for identifying the medium is magnetically recorded. A step of performing orientation by applying a predetermined DC or AC magnetic field before the second magnetic layer is dried and solidified, and a step of drying and solidified the oriented second magnetic layer.
【０００７】添付図面に基づいて本発明を詳細に説明す
る。図１は本発明の磁気記録媒体の断面図であり、非磁
性材料からなる基体１、第１の磁性層２、第２の磁性層
３から構成される。第２の磁性層３は、高分子樹脂バイ
ンダ中に保磁力４０００Ｏｅ以下の強磁性粉末を分散し
た磁性塗料から形成され、単位面積あたりの磁気出力が
高い部分３１と単位面積あたりの磁気出力が低い部分３
２とが、所定の寸法で交互に形成されている。The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a magnetic recording medium of the present invention, which comprises a substrate 1 made of a non-magnetic material, a first magnetic layer 2 and a second magnetic layer 3. The second magnetic layer 3 is formed of a magnetic paint in which a ferromagnetic resin having a coercive force of 4000 Oe or less is dispersed in a polymer resin binder, and has a high magnetic output 31 per unit area and a low magnetic output per unit area. Part 3
2 and 2 are formed alternately with a predetermined size.
【０００８】基体１は、ポリエチレンテレフタレート、
硬質塩化ビニル、ポリプロピレン、紙など通常の磁気カ
ード、磁気テープ、磁気シート等に使われる材料が使用
される。第１の磁性層２は、通常の磁気カードや磁気テ
ープの磁気情報記録用被膜と同じであってよく、例えば
γＦｅ2 Ｏ3 、コバルト被着γＦｅ2 Ｏ3 、バリウムフ
ェライトなどの磁性粉をバインダー中に分散して作製し
た第１の磁性塗料を、乾燥後の厚さが４〜２０μｍ程度
となるよう、通常の磁気記録媒体を製造する公知の方法
で均一に塗布されている。The substrate 1 is polyethylene terephthalate,
Materials used for ordinary magnetic cards such as hard vinyl chloride, polypropylene and paper, magnetic tapes, magnetic sheets, etc. are used. The first magnetic layer 2 may be the same as a magnetic information recording film of a normal magnetic card or a magnetic tape, and for example, magnetic powder such as γFe 2 O 3 , cobalt adhered γFe 2 O 3 and barium ferrite is used as a binder. The first magnetic coating material prepared by being dispersed therein is uniformly applied by a known method for producing an ordinary magnetic recording medium so that the thickness after drying is about 4 to 20 μm.
【０００９】第１の磁性層２の上には、第１の磁性層と
は同一または異なる構成を有し、保磁力４０００Ｏｅ以
下の磁性粉をバインダー中に分散して作製した第２の磁
性塗料を塗布・乾燥して形成した第２の磁性層３が設け
られている。この第２の磁性塗料を塗布・乾燥するとき
には、第１の磁性層２には、所定の位置に定められたパ
ターンが磁気記録されている必要がある。このパターン
は、例えば媒体を特定するための番号などの識別情報を
あらわすものであり、例えば媒体の走行方向に対して所
定の領域での残留磁化の極性が交互に反転するよう通常
の磁気ヘッドと媒体搬送手段を用いて磁気記録すること
により形成されている。識別情報はＲＺ、ＰＷＭ、Ｆ
Ｍ、ＰＭ、ＭＦＭなど公知の方式で符号化されている。On the first magnetic layer 2, a second magnetic paint having the same or different structure as the first magnetic layer and prepared by dispersing magnetic powder having a coercive force of 4000 Oe or less in a binder. A second magnetic layer 3 formed by applying and drying is provided. When applying and drying the second magnetic paint, the first magnetic layer 2 must be magnetically recorded with a pattern defined at a predetermined position. This pattern represents identification information such as a number for identifying the medium.For example, a normal magnetic head is used so that the polarity of the residual magnetization in a predetermined region is alternately inverted with respect to the traveling direction of the medium. It is formed by magnetic recording using a medium carrying means. The identification information is RZ, PWM, F
It is encoded by a known method such as M, PM, and MFM.
【００１０】図２は本発明の磁気記録媒体を製造する過
程を模式的に示したものである。図２の（ａ）は第２の
磁性層が塗布される直前の状態を示したものであり、第
１の磁性層２には参照番号２１、２２で示したように逆
の極性で磁化された識別信号作製用の信号が所定の長さ
で交互に記録されている。なお、第１の磁性層２に磁気
記録する方法としては、第１磁性層２を交流消磁して残
留磁化をゼロとしておき、所定の領域のみを同一の極性
に磁化してもよい。FIG. 2 schematically shows a process of manufacturing the magnetic recording medium of the present invention. FIG. 2A shows a state immediately before the second magnetic layer is applied. The first magnetic layer 2 is magnetized with the opposite polarities as shown by reference numerals 21 and 22. The signals for producing the identification signal are recorded alternately with a predetermined length. As a method of magnetically recording on the first magnetic layer 2, the first magnetic layer 2 may be demagnetized with an alternating current so that the residual magnetization is zero, and only predetermined regions are magnetized to the same polarity.
【００１１】このように磁気記録された第１の磁性層２
の上に、第２の磁性塗料を通常の磁気記録媒体を製造す
る公知の方法で均一に塗布する。さらに乾燥固化する前
に所定の方向及び強さの磁界中にさらすことにより配向
をかける。図２の（ｂ）は配向磁界がかかっているとき
の、第２の磁性層３に加わる磁界の強さを模式的に表し
たものである。参照番号３１で示した箇所では、第１の
磁性層２から発生する信号磁界の向きと配向磁界の向き
（図２の（ｂ）では右向きに表示）が一致するので第２
の磁性層に加わる磁界の強さはより強くなっており、参
照番号３２で示した箇所では、第１の磁性層２から発生
する信号磁界の向きと配向磁界の向きとが打ち消しあっ
て第２の磁性層に加わる磁界の強さが弱くなっている。
つまり第２の磁性層３には、第１の磁性層２に記録され
た信号のパターンに従って、強い磁界が加わる箇所３１
と弱い磁界が加わる箇所３２とが交互に現れる。一般に
流動状態にある磁性粒子は、磁界の強い箇所に集中する
ので、第２の磁性塗料中の磁性粒子は、図２の（ｃ）に
示すようにより強い磁界が加わった箇所３１に集中す
る。第２の磁性塗料を塗布し配向をかけた後、公知の方
法により第２の磁性層は乾燥固化される。この結果、第
２の磁性層３には磁性粒子が集中して磁性粒子の含有率
が高く、よって単位面積あたりの磁気出力が高い箇所３
１と、磁性粒子の含有率が低く、よって単位面積あたり
の磁気出力が低い箇所３２とが交互に形成される。この
ようにして、第１の磁性層１に記録された媒体固有の識
別信号が、第２の磁性層３中に、単位面積あたりの磁気
出力の違いにより符号化されたパターンとして複製され
る。なお、前述した第２の磁性層中の磁性粒子が集中す
る効果は、第２の磁性塗料のバインダーの粘性が低く磁
性粒子の流動性が高いほど大きい。The first magnetic layer 2 magnetically recorded in this way
Then, the second magnetic coating material is uniformly applied by a known method for producing a usual magnetic recording medium. Orientation is applied by exposure to a magnetic field of defined direction and strength before further drying and solidification. 2B schematically shows the strength of the magnetic field applied to the second magnetic layer 3 when the orientation magnetic field is applied. In the portion indicated by reference numeral 31, the direction of the signal magnetic field generated from the first magnetic layer 2 and the direction of the orientation magnetic field (indicated to the right in FIG.
The strength of the magnetic field applied to the magnetic layer is stronger, and at the location indicated by reference numeral 32, the direction of the signal magnetic field generated from the first magnetic layer 2 and the direction of the orientation magnetic field cancel each other out. The strength of the magnetic field applied to the magnetic layer is weak.
That is, in the second magnetic layer 3, a portion 31 to which a strong magnetic field is applied according to the pattern of the signal recorded in the first magnetic layer 2.
And a portion 32 to which a weak magnetic field is applied alternately appear. In general, the magnetic particles in a fluidized state are concentrated in a portion where the magnetic field is strong, so that the magnetic particles in the second magnetic paint are concentrated in a portion 31 where a stronger magnetic field is applied as shown in FIG. After the second magnetic coating material is applied and oriented, the second magnetic layer is dried and solidified by a known method. As a result, the magnetic particles are concentrated in the second magnetic layer 3 and the content ratio of the magnetic particles is high, and thus the magnetic output per unit area is high.
1 and a portion 32 having a low magnetic particle content and thus a low magnetic output per unit area are alternately formed. In this way, the medium-specific identification signal recorded in the first magnetic layer 1 is duplicated in the second magnetic layer 3 as a pattern encoded by the difference in magnetic output per unit area. The effect of concentrating the magnetic particles in the second magnetic layer described above is greater as the viscosity of the binder of the second magnetic coating is lower and the fluidity of the magnetic particles is higher.
【００１２】また乾燥固化する前の第２の磁性塗料に印
加する配向磁界としては、直流磁界でも交流磁界でもよ
く、何れの場合も無配向のときより磁性粒子が集中する
効果が高いが、直流磁界の場合は特に顕著であり好まし
い。なお交流磁界の場合は図３に示すように、磁性粒子
は第１の磁性層２に記録された信号の磁化が反転する箇
所に集中する。印加する配向磁界の強さは、第２の磁性
塗料の流体での保磁力の２．５倍より大きく、且つ第１
の磁性層２に記録した信号が消去されないように第１の
磁性層２の保磁力より小さい値が選ばれる。The orientation magnetic field applied to the second magnetic coating material before being dried and solidified may be a DC magnetic field or an AC magnetic field, and in any case, the effect of concentrating magnetic particles is higher than that in the non-oriented state. The magnetic field is particularly remarkable and preferable. In the case of an alternating magnetic field, as shown in FIG. 3, the magnetic particles are concentrated at the location where the magnetization of the signal recorded in the first magnetic layer 2 is reversed. The strength of the applied orientation magnetic field is greater than 2.5 times the coercive force of the fluid of the second magnetic paint, and
A value smaller than the coercive force of the first magnetic layer 2 is selected so that the signal recorded in the magnetic layer 2 is not erased.
【００１３】前述のように識別信号パターンは、主に第
１の磁性層２に記録された信号から発生する磁界によっ
て形成されるので、第２の磁性層３には第１の磁性層２
自体に記録できる情報記録密度と同等の情報密度で識別
信号を形成することができる。例えば『磁気透かし』な
どの従来技術によって付与された媒体固有の識別コード
は、１ビットを表すのに０．４ｍｍ程度必要であったの
に対し、本発明の磁気記録媒体は、単位面積あたりの磁
気出力が異なる領域の信号読み取り方向における長さは
０．０６ｍｍ以下とすることができる。一方、第１の磁
性層２に記録された信号の磁化反転間隔が広くなると、
第２の磁性層３に及ぼす磁界強度が弱くなるので、単位
面積あたりの磁気出力が高い領域の信号読み取り方向に
おける長さは１ｍｍ以内であることが好ましい。As described above, the identification signal pattern is formed mainly by the magnetic field generated from the signal recorded in the first magnetic layer 2, so that the second magnetic layer 3 has the first magnetic layer 2.
The identification signal can be formed with an information density equivalent to the information recording density that can be recorded on itself. For example, a medium-specific identification code such as "magnetic watermark" provided by a conventional technique requires about 0.4 mm to represent one bit, whereas the magnetic recording medium of the present invention has a unit area per unit area. The length in the signal reading direction of the regions having different magnetic outputs can be 0.06 mm or less. On the other hand, if the magnetization reversal interval of the signal recorded in the first magnetic layer 2 becomes wider,
Since the magnetic field strength exerted on the second magnetic layer 3 becomes weak, the length in the signal reading direction of the region where the magnetic output is high per unit area is preferably within 1 mm.
【００１４】第２の磁性層３に使用される磁性粉として
は、第１の磁性層２に記録された信号から発生する磁界
によって磁化されるものであればよく、パーマロイ、セ
ンダスト、アモルファスなどの鱗片状高透磁率磁性金属
粉や、鉄粉などの軟磁性金属粉、及びＭｎ−Ｚｎ、Ｎｉ
−Ｚｎなどの軟磁性フェライト粉を使用することができ
る。また、γＦｅ2 Ｏ3 、マグネタイト、コバルト被着
γＦｅ2 Ｏ3 、バリウムフェライトなど、磁気カードや
磁気テープなどに信号記録用として用いられる材料であ
っても、塗料状態において磁性粒子の流動性が高く、且
つ配向磁界の強度を適当に選択することにより、第１の
磁性層２に記録された信号によって磁性粒子の集中が起
こる。磁性塗料の流体での保磁力は、磁性粒子の形状に
もよるが一般には乾燥固化した後の保磁力に比べてかな
り低い。従って、第２の磁性層３の乾燥固化後の保磁力
が、第１の磁性層２の乾燥固化後の保磁力よりも低い必
要はない。しかしながら、第２の磁性層を磁化して読み
取る際には、第２の磁性層が容易に磁化しなければ充分
な読取りないし識別出力を得ることができないので、第
２の磁性層の磁性粒子の保磁力の上限は４０００Ｏｅで
ある。The magnetic powder used in the second magnetic layer 3 may be any that can be magnetized by a magnetic field generated from a signal recorded in the first magnetic layer 2, such as permalloy, sendust, and amorphous. Scale-like high magnetic permeability magnetic metal powder, soft magnetic metal powder such as iron powder, and Mn-Zn, Ni
Soft magnetic ferrite powder such as -Zn can be used. In addition, even in materials such as γFe 2 O 3 , magnetite, γFe 2 O 3 coated with cobalt, barium ferrite, and the like used for signal recording on magnetic cards and magnetic tapes, the fluidity of magnetic particles is high in the paint state. , And by appropriately selecting the strength of the orientation magnetic field, the magnetic particles are concentrated by the signal recorded in the first magnetic layer 2. The coercive force of a magnetic paint in a fluid depends on the shape of the magnetic particles, but is generally much lower than the coercive force after being dried and solidified. Therefore, the coercive force of the second magnetic layer 3 after drying and solidification need not be lower than the coercive force of the first magnetic layer 2 after drying and solidification. However, when the second magnetic layer is magnetized and read, sufficient reading or identification output cannot be obtained unless the second magnetic layer is easily magnetized. The upper limit of coercive force is 4000 Oe.
【００１５】以上説明したように本発明の磁気記録媒体
の特徴は、第１の磁性層２に記録した信号から発生する
磁界による影響で、第２の磁性層３の磁性粒子を局部的
に集中させることにあるので、第１の磁性層２と第２の
磁性層３とは必ずしも互いに接合している必要はなく、
本発明の主旨が生かせる範囲内の非磁性の中間層を第１
の磁性層２と第２の磁性層３との間に設けてもよい。As described above, the characteristic feature of the magnetic recording medium of the present invention is that the magnetic particles in the second magnetic layer 3 are locally concentrated due to the influence of the magnetic field generated from the signal recorded in the first magnetic layer 2. Therefore, the first magnetic layer 2 and the second magnetic layer 3 do not necessarily have to be joined to each other.
The first non-magnetic intermediate layer is within the scope of the present invention.
It may be provided between the magnetic layer 2 and the second magnetic layer 3.
【００１６】本発明の磁気記録媒体の読み取りにあたっ
ては、先ず第１の磁性層２の識別信号が記録されている
箇所に、通常の磁気記録媒体を記録再生できる装置によ
り、第１の磁性層の保磁力の３倍以上の直流磁界を印加
し、第１の磁性層２を一定の向きに飽和磁化する。この
ことによって第１の記録層２に記録されていた識別信号
作製用の信号は完全に消去される。第２の磁性層３に形
成された識別情報の読み取りは以下の方法で行う。図４
は、本発明による磁気記録媒体の読み取りの原理を示す
図であり、読み取りヘッド４にはバイアスコイル５と読
み取り用のコイル６とが設けられている。識別情報の読
み取りに当たっては、読み取り磁気ヘッド４のバイアス
コイル５に一定のバイアス電流Ｉｂを印加し、前部ギャ
ップ部７からバイアス磁界を発生させながら前記磁気記
録媒体の識別情報記録部分を走査する。磁気ヘッド４の
前部ギャップ部７が識別情報記録部分を通過するとき、
単位面積あたりの磁気出力が高い部分３１と低い部分３
２との境界部分で磁気抵抗が変化するので、読み取りコ
イル６と鎖交する磁束が変化し、読み取りコイル６の両
端には磁束の変化量に比例した出力波形８が発生する。
こうして第２の磁性層３の所定の箇所に形成された識別
情報を読み取ることができる。In reading the magnetic recording medium of the present invention, first, a device for recording / reproducing an ordinary magnetic recording medium is used to record the first magnetic layer on the portion of the first magnetic layer 2 where the identification signal is recorded. A DC magnetic field that is three times or more the coercive force is applied to saturate the first magnetic layer 2 in a fixed direction. As a result, the signal for producing the identification signal recorded in the first recording layer 2 is completely erased. The identification information formed on the second magnetic layer 3 is read by the following method. Figure 4
FIG. 4 is a diagram showing the principle of reading the magnetic recording medium according to the present invention, in which the reading head 4 is provided with a bias coil 5 and a reading coil 6. In reading the identification information, a constant bias current Ib is applied to the bias coil 5 of the read magnetic head 4 to scan the identification information recording portion of the magnetic recording medium while generating a bias magnetic field from the front gap portion 7. When the front gap portion 7 of the magnetic head 4 passes through the identification information recording portion,
Part 31 where the magnetic output per unit area is high and part 3 where the magnetic output is low
Since the magnetic resistance changes at the boundary with 2, the magnetic flux linked to the read coil 6 changes, and an output waveform 8 proportional to the change amount of the magnetic flux is generated at both ends of the read coil 6.
In this way, the identification information formed at the predetermined location on the second magnetic layer 3 can be read.
【００１７】なお、第２の磁性層３に、パーマロイ、セ
ンダスト、アモルファスなどの鱗片状高透磁率磁性金属
粉、鉄粉などの軟磁性金属粉及びＭｎ−Ｚｎ、Ｎｉ−Ｚ
ｎなどの軟磁性フェライト粉を使用した場合は、バイア
スをかけて読み取った後の識別情報記録部分には残留磁
化が生じないので、磁気現像液等で識別情報を目視する
ことは不可能であり特に好ましい。In the second magnetic layer 3, scale-like high-permeability magnetic metal powder such as permalloy, sendust, and amorphous, soft magnetic metal powder such as iron powder, and Mn-Zn, Ni-Z.
When soft magnetic ferrite powder such as n is used, residual magnetization does not occur in the identification information recording portion after reading with bias applied, so it is impossible to visually identify the identification information with a magnetic developer or the like. Particularly preferred.
【００１８】なお、第２の磁性層３にγＦｅ2 Ｏ3 、マ
グネタイト、コバルト被着γＦｅ2Ｏ3 、バリウムフェ
ライトなど、磁気カードや磁気テープなどに信号記録用
として用いられる材料を用いた場合は、以下の方法でも
識別信号の読み取りが可能である。すなわち、第１の磁
性層２を保磁力の３倍以上の直流磁界を印加し識別情報
作製用の信号を消磁したときには、第２の磁性層３も同
時に一定の向きに飽和磁化される。直流磁界を取り去っ
た後の第２の磁性層３の識別情報記録部分の残留磁化
は、単位体積中の磁性粒子の含有率が高い部分が、単位
体積中の磁性粒子の含有率が低い部分に比べ大きくな
る。つまり、第２の磁性層３に形成された磁性粒子の含
有率が高い部分と低い部分にあわせて、残留磁化が強い
部分と弱い部分とが交互に現れる。この残留磁化の強い
部分と弱い部分とを、通常の読み取り用磁気ヘッドによ
り走査すると、媒体上の残留磁化の強さが変化する境界
部分で、磁化の変化量に比例した出力電圧が読み取りコ
イルの両端から発生する。こうして第２の磁性層３の所
定の箇所に形成された、識別情報を読み取ることができ
る。When the second magnetic layer 3 is made of γFe 2 O 3 , magnetite, cobalt-coated γFe 2 O 3 , barium ferrite, or any other material used for signal recording in magnetic cards or magnetic tapes, The identification signal can also be read by the following method. That is, when a DC magnetic field having a coercive force of 3 times or more is applied to the first magnetic layer 2 to demagnetize the signal for producing identification information, the second magnetic layer 3 is also saturated and magnetized in a fixed direction at the same time. The residual magnetization of the identification information recording portion of the second magnetic layer 3 after removing the DC magnetic field is such that the portion with a high content of magnetic particles in the unit volume is the portion with a low content of magnetic particles in the unit volume. It will be larger than that. That is, in accordance with the portion where the content of the magnetic particles formed in the second magnetic layer 3 is high and the portion where the content of the magnetic particles is low, a portion having a strong residual magnetization and a portion having a weak residual magnetization appear alternately. When a portion having a strong residual magnetization and a portion having a weak residual magnetization are scanned by a normal reading magnetic head, an output voltage proportional to the amount of change in the magnetization is output at the boundary portion where the strength of the residual magnetization on the medium changes. It originates from both ends. In this way, the identification information formed at the predetermined location on the second magnetic layer 3 can be read.
【００１９】なお、先に述べた乾燥固化前の第２の磁性
塗料中の磁性粒子が配向磁界によって集中する効果は、
第１の磁性層に記録した信号磁界の強さに依存し、従っ
て第１の磁性層の残留磁束に依存する。図５は保磁力が
２７５０エルステッドのバリウムフェライトを第１の磁
性層とし、また第２の磁性層としては保磁力が２０エル
ステッド以下の高透磁率Ｆｅ−Ｓｉ合金系の鱗片状磁性
粉を厚さ１０μｍに塗布したときに、第１の磁性層の残
留磁束の値に対する第２の磁性層に形成された識別信号
の出力レベルの関係を示す図である。縦軸の出力レベル
は任意目盛りとしてある。図５から、特に０．５マック
スウェル／ｃｍ以上で第２の磁性層の識別信号の出力レ
ベルが大きくなることがわかる。The effect of concentrating the magnetic particles in the second magnetic paint before drying and solidifying by the orientation magnetic field is as follows.
It depends on the strength of the signal magnetic field recorded in the first magnetic layer, and thus on the residual magnetic flux of the first magnetic layer. FIG. 5 shows barium ferrite having a coercive force of 2750 Oersted as the first magnetic layer, and as the second magnetic layer, a magnetic flux of high permeability Fe—Si alloy system having a coercive force of 20 Oersted or less is thick. It is a figure which shows the relationship of the output level of the identification signal formed in the 2nd magnetic layer with respect to the value of the residual magnetic flux of a 1st magnetic layer, when apply | coating to 10 micrometers. The output level on the vertical axis is an arbitrary scale. From FIG. 5, it can be seen that the output level of the identification signal of the second magnetic layer increases especially at 0.5 Maxwell / cm or more.
【００２０】本発明の主旨から、媒体を識別するための
所定の信号が記録される第２の磁性層は、識別情報記録
領域以外の第１の磁性層全部を覆って形成してもよい
し、また識別情報記録領域を含む第１の磁性層上の特定
の領域にのみ形成してもよい。特に前者の場合は、識別
情報記録領域以外を、例えば同じ出願人による特開昭６
３−３４７２７号公報に開示されているような、保磁力
が異なる２つ以上の磁性層を積層してなる磁気記録媒体
として使用できるので、両者の組み合わせにより一層機
密性を高めることができる。また３層以上の磁性層をも
つ磁気記録媒体においては、第１の磁性層以外の任意の
磁性層に前記の識別信号を形成することができることは
明らかである。For the purpose of the present invention, the second magnetic layer in which a predetermined signal for identifying the medium is recorded may be formed so as to cover the entire first magnetic layer except the identification information recording area. Alternatively, it may be formed only in a specific area on the first magnetic layer including the identification information recording area. Especially in the former case, except the identification information recording area, for example, Japanese Patent Laid-Open No.
Since it can be used as a magnetic recording medium formed by laminating two or more magnetic layers having different coercive forces as disclosed in JP-A-3-34727, the confidentiality can be further improved by combining the two. Further, in a magnetic recording medium having three or more magnetic layers, it is obvious that the identification signal can be formed in any magnetic layer other than the first magnetic layer.
【００２１】なお本発明の磁気記録媒体は、シリコンな
どの剥離剤を塗布した基体の上に前述した方法で少なく
とも第１の磁性層及び識別情報を含む第２の磁性層を形
成し、その上に接着剤を塗布した転写用テープを先ず作
製し、硬質塩化ビニルやポリエチレンテレフタレートな
どの基体の所定の位置に、前記テープを転写することに
より作製してもよい。In the magnetic recording medium of the present invention, at least the first magnetic layer and the second magnetic layer containing the identification information are formed on the substrate coated with a release agent such as silicon by the above-described method, and the magnetic layer is formed on the first magnetic layer. Alternatively, a transfer tape having an adhesive applied thereto may be first prepared, and then the tape may be transferred to a predetermined position of a substrate such as hard vinyl chloride or polyethylene terephthalate.
【００２２】[0022]
【実施例】以下、本発明を実施例および比較例を用いて
更に説明する。 実施例１ 厚さ１８８μｍの白色ポリエステルフィルム基体の片面
全面に保磁力が２７５０エルステッドのバリウムフェラ
イト磁性粉をバインダー樹脂、分散剤、硬化剤、その他
添加剤と溶剤とを混合・分散して作製した磁気塗料をグ
ラビア法で塗布し、乾燥後の厚みが１２μｍで残留磁化
が１．６マックスウェル／ｃｍの第１の磁性層を得た。
第１の磁性層に、通常の磁気媒体を記録することができ
る磁気記録装置で、所定の位置に記録密度が２５ＦＣＩ
及び４００ＦＣＩの連続信号及び１０５ＢＰＩのＦＭ変
調信号を所定の強さで記録した。この第１の磁性層の上
に、高透磁率のＦｅ−Ｓｉ系合金の鱗片状粉末をバイン
ダー樹脂、分散剤、硬化剤、その他添加剤と溶剤とを混
合・分散して作製した磁気塗料をナイフコート法で塗布
し、乾燥前に２００エルステッドの磁界にて直流配向を
かけ、乾燥後の厚みが１２μｍの第２の磁性層を得た。EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples. Example 1 A magnetic material prepared by mixing and dispersing a binder resin, a dispersant, a curing agent, and other additives and a solvent with barium ferrite magnetic powder having a coercive force of 2750 Oersted on one entire surface of a white polyester film substrate having a thickness of 188 μm. The coating material was applied by a gravure method to obtain a first magnetic layer having a thickness of 12 μm after drying and a residual magnetization of 1.6 Maxwell / cm.
A magnetic recording device capable of recording an ordinary magnetic medium on the first magnetic layer, with a recording density of 25 FCI at a predetermined position.
And a continuous signal of 400 FCI and an FM modulated signal of 105 BPI were recorded at a predetermined intensity. A magnetic coating material prepared by mixing and dispersing a binder resin, a dispersant, a curing agent, and other additives and a solvent on a scale-like powder of a high magnetic permeability Fe-Si alloy on the first magnetic layer. A second magnetic layer having a thickness of 12 μm after drying was obtained by applying a knife coating method and applying a DC orientation in a magnetic field of 200 Oersted before drying.
【００２３】実施例２ 実施例１と同じ方法で作製した第１の磁性層の上に、粒
径が５μｍ以下のカルボニル鉄粉をバインダー樹脂、分
散剤、硬化剤、その他添加剤と溶剤とを混合・分散して
作製した磁気塗料をシルク印刷法で塗布し、乾燥前に２
００エルステッドの直流磁界にて配向をかけ、乾燥後の
厚みが７μｍの第２の磁性層を得た。Example 2 On the first magnetic layer prepared by the same method as in Example 1, carbonyl iron powder having a particle size of 5 μm or less was added as a binder resin, a dispersant, a curing agent, other additives and a solvent. Apply the magnetic paint prepared by mixing and dispersing by silk printing method, and apply 2 before drying.
Orientation was applied with a DC magnetic field of 00 Oersted to obtain a second magnetic layer having a thickness of 7 μm after drying.
【００２４】実施例３ 実施例１と同じ方法で作製した第１の磁性層の上に、実
施例２と同じ方法で作製した第２の磁気塗料を塗布し、
乾燥前に４００エルステッド（Ｏ−ｐ）の交流磁界にて
配向をかけ、乾燥後の厚みが７μｍの第２の磁性層を得
た。Example 3 A second magnetic coating material prepared in the same manner as in Example 2 was applied onto the first magnetic layer prepared in the same manner as in Example 1,
Before drying, orientation was applied with an alternating magnetic field of 400 Oersted (O-p) to obtain a second magnetic layer having a thickness of 7 μm after drying.
【００２５】実施例４ 実施例１と同じ方法で作製した第１の磁性層の上に、保
磁力が３００エルステッドのγＦｅ2 Ｏ3 をバインダー
樹脂、分散剤、硬化剤、その他添加剤と溶剤とを混合・
分散して作製した磁気塗料をグラビア法で塗布し、乾燥
前に８００エルステッドの直流磁界で配向をかけ、乾燥
後の厚みが１０μｍの第２の磁性層を得た。Example 4 γFe 2 O 3 having a coercive force of 300 oersted was formed as a binder resin, a dispersant, a curing agent, other additives and a solvent on the first magnetic layer prepared by the same method as in Example 1. Mixed
The magnetic coating material prepared by dispersion was applied by a gravure method and oriented by a direct current magnetic field of 800 Oersted before drying to obtain a second magnetic layer having a thickness after drying of 10 μm.
【００２６】実施例５ 実施例１と同じ方法で作製した第１の磁性層の上に、保
磁力が６５０エルステッドのコバルト被着γＦｅ2 Ｏ3
をバインダー樹脂、分散剤、硬化剤、その他添加剤と溶
剤とを混合・分散して作製した磁気塗料をグラビア法で
塗布し、乾燥前に１２００エルステッドの直流磁界で配
向をかけ、乾燥後の厚みが１０μｍの第２の磁性層を得
た。Example 5 Cobalt-deposited γFe 2 O 3 having a coercive force of 650 Oersted was formed on the first magnetic layer prepared by the same method as in Example 1.
Is coated with a magnetic paint prepared by mixing and dispersing a binder resin, a dispersant, a curing agent, other additives and a solvent by a gravure method, and is oriented by a DC magnetic field of 1200 oersted before drying, and the thickness after drying. To obtain a second magnetic layer having a thickness of 10 μm.
【００２７】実施例６ 実施例１と同じ方法で作製した第１の磁性層の上に、保
磁力が１０００エルステッドのバリウムフェライトをバ
インダー樹脂、分散剤、硬化剤、その他添加剤と溶剤と
を混合・分散して作製した磁気塗料をグラビア法で塗布
し、乾燥前に１２００エルステッドの直流磁界で配向を
かけ、乾燥後の厚みが８μｍの第２の磁性層を得た。Example 6 Barium ferrite having a coercive force of 1000 Oersted was mixed with a binder resin, a dispersant, a curing agent, and other additives and a solvent on the first magnetic layer prepared by the same method as in Example 1. The magnetic paint prepared by dispersion was applied by a gravure method and oriented by a direct current magnetic field of 1200 Oersted before drying to obtain a second magnetic layer having a thickness after drying of 8 μm.
【００２８】実施例７ 実施例１と同じ方法で作製した第１の磁性層の上に、第
１の磁性層と同じ磁性塗料を同じ方法で塗布し、乾燥前
に１５００エルステッドの直流磁界で配向をかけ、乾燥
後の厚みが６μｍの第２の磁性層を得た。Example 7 On the first magnetic layer prepared by the same method as in Example 1, the same magnetic coating material as that for the first magnetic layer was applied by the same method, and the alignment was performed with a direct current magnetic field of 1500 Oersted before drying. Then, a second magnetic layer having a thickness after drying of 6 μm was obtained.
【００２９】比較例１ 実施例１と同じ方法で作製した第１の磁性層の上に、実
施例２と同じ方法で作製した第２の磁気塗料を塗布し、
配向をかけずに乾燥し、厚みが７μｍの第２の磁性層を
得た。Comparative Example 1 A second magnetic coating material prepared by the same method as in Example 2 was applied onto the first magnetic layer prepared by the same method as in Example 1,
It was dried without orientation to obtain a second magnetic layer having a thickness of 7 μm.
【００３０】比較例２ 実施例１と同じ方法で作製した第１の磁性層の上に、実
施例４と同じ方法で作製した第２の磁気塗料を塗布し、
配向をかけずに乾燥し、厚みが１０μｍの第２の磁性層
を得た。Comparative Example 2 A second magnetic coating material prepared in the same manner as in Example 4 was applied onto the first magnetic layer prepared in the same manner as in Example 1,
It was dried without orientation, and a second magnetic layer having a thickness of 10 μm was obtained.
【００３１】比較例３ 実施例１と同じ方法で作製した第１の磁性層の上に、保
磁力が７０００Ｏｅのストロンチウムフェライトをバイ
ンダ樹脂、分散剤、硬化剤、その他添加剤と溶剤とを混
合し、分散して作製した磁気塗料を、グラビア法で塗布
し、乾燥前に１５００Ｏｅの直流磁界で配向をかけ、乾
燥後の厚みが６μｍの第２の磁性層を得た。 比較例４ 実施例１と同じ方法で作製した第１の磁性層の上に、保
磁力が４５００Ｏｅのバリウムフェライトをバインダ樹
脂、分散剤、硬化剤、その他添加剤と溶剤とを混合し、
分散して作製した磁気塗料を、グラビア法で塗布し、乾
燥前に１５００Ｏｅの直流磁界で配向をかけ、乾燥後の
厚みが６μｍの第２の磁性層を得た。Comparative Example 3 On the first magnetic layer prepared in the same manner as in Example 1, strontium ferrite having a coercive force of 7,000 Oe was mixed with a binder resin, a dispersant, a curing agent, other additives and a solvent. The magnetic paint prepared by dispersion was applied by a gravure method, and oriented by a direct current magnetic field of 1500 Oe before drying to obtain a second magnetic layer having a thickness after drying of 6 μm. Comparative Example 4 Barium ferrite having a coercive force of 4500 Oe was mixed with a binder resin, a dispersant, a curing agent, and other additives and a solvent on the first magnetic layer produced by the same method as in Example 1,
The magnetic paint prepared by dispersion was applied by a gravure method and oriented by a direct current magnetic field of 1500 Oe before drying to obtain a second magnetic layer having a thickness after drying of 6 μm.
【００３２】実施例１〜７及び比較例１〜４で作製した
磁気シートを所定の大きさに打ち抜き磁気カードを得
た。各実施例及び各比較例で得た磁気カードを以下の方
法で読み取った。保磁力が２７５０エルステッドの磁気
媒体を飽和書き込みできる磁気ヘッドを装着したリーダ
ー・ライターで、先ず第１の磁性層に書き込まれた信号
を直流消去した。次に同じリーダー・ライターに装着さ
れたバイアスコイルを有する読み取りヘッドにバイアス
電流を流し、ヘッドの前部ギャップから約８００エルス
テッドの、バイアス磁界を印加しながら各カードの再生
出力（ｐｅａｋ−ｐｅａｋ）を読み取った。各カードの
２５ＦＣＩ及び４００ＦＣＩの連続信号の再生出力と１
０５ＢＰＩ信号の復調結果の一覧を表１に示す。なお２
５ＦＣＩと４００ＦＣＩの再生出力は、実施例４の第１
の磁性層に２１０ＦＣＩの信号を飽和書き込みした後に
読み取った出力を１００％とした相対出力で示した。The magnetic sheets produced in Examples 1 to 7 and Comparative Examples 1 to 4 were punched into a predetermined size to obtain magnetic cards. The magnetic cards obtained in each example and each comparative example were read by the following method. First, the signal written in the first magnetic layer was DC erased by a reader / writer equipped with a magnetic head capable of saturation writing a magnetic medium having a coercive force of 2750 Oersted. Next, a bias current is applied to a read head having a bias coil attached to the same reader / writer, and the read output (peak-peak) of each card is applied while applying a bias magnetic field of about 800 Oersted from the front gap of the head. Read Playback output of continuous signals of 25 FCI and 400 FCI of each card and 1
Table 1 shows a list of the demodulation results of the 05BPI signal. 2
The reproduction outputs of 5 FCI and 400 FCI are the same as those in the first embodiment.
The output read after the 210 FCI signal was saturated and written in the magnetic layer of No. 2 was shown as a relative output with the output read as 100%.
【００３３】実施例１〜７は何れの場合も、２５ＦＣＩ
及び４００ＦＣＩの信号は第１の磁性層の出力に対して
２０％以上の出力が得られ、１０５ＢＰＩの変調信号は
ＳＮ比もよく問題なく信号を復調することができた。ま
た、実施例２、３と比較例１及び実施例４と比較例２と
の比較から、第２の磁性層を塗布する際に配向をかける
ことの有効性が認められた。一方、比較例３〜４のよう
に高い保磁力を有する磁性粒子を使用すると配向をかけ
ても出力が非常に低く信号の復調ができないことが分か
る。なお本発明の磁気記録媒体においては、第２の磁性
層の上に着色隠蔽層、印刷層、保護層などを適宜設けて
よいし、必要に応じて感熱印字層を設けてもよいことは
明らかである。In any of Examples 1 to 7, 25 FCI
With respect to the signals of 400 FCI and 400 FCI, 20% or more of the output of the first magnetic layer was obtained, and the modulated signal of 105 BPI had a good SN ratio and could be demodulated without any problem. From the comparison between Examples 2 and 3 and Comparative Example 1 and between Example 4 and Comparative Example 2, it was confirmed that the orientation is effective when the second magnetic layer is applied. On the other hand, when magnetic particles having a high coercive force as in Comparative Examples 3 to 4 are used, the output is very low even if orientation is applied, and it is not possible to demodulate a signal. In the magnetic recording medium of the present invention, it is clear that a colored hiding layer, a printing layer, a protective layer, etc. may be appropriately provided on the second magnetic layer, and a thermal printing layer may be provided if necessary. Is.
【００３４】[0034]
【表１】 [Table 1]
【００３５】[0035]
【発明の効果】以上のように、本発明によると次の効果
が得られる。 媒体を特定するための識別手段を、磁気配向を利用し
て媒体の製造段階で高度に造り込むので、媒体を破壊す
ること無しに識別情報を後からつけ加えたり、変更する
ことは不可能であり、極めて機密性が高い磁気媒体を提
供することができる。 識別情報の存在を外からは確認することができないば
かりか、サンドペーパーによって媒体表面を削り取って
も視認することは困難である。 特殊な材料や製造設備を必要としないので低コストで
ある。 磁気透かしや磁気バーコードなどと比較し高記録密度
の識別信号を付与することが可能である。As described above, according to the present invention, the following effects can be obtained. Since the identification means for identifying the medium is highly built at the manufacturing stage of the medium by utilizing the magnetic orientation, it is impossible to add or change the identification information afterwards without destroying the medium. It is possible to provide a magnetic medium with extremely high confidentiality. The existence of the identification information cannot be confirmed from the outside, and it is difficult to visually recognize even if the medium surface is scraped off with sandpaper. Low cost because no special material or manufacturing equipment is required. It is possible to add an identification signal with a high recording density as compared with a magnetic watermark or a magnetic barcode.
【図１】本発明の磁気記録媒体の構成を示す断面図であ
る。FIG. 1 is a cross-sectional view showing the structure of a magnetic recording medium of the present invention.
【図２】本発明の原理を説明する図式的な断面図であ
り、（ａ）は第１層の形成とその磁気記録を示し、
（ｂ）は第２層の形成と磁気配向による磁化状態を示
し、（ｃ）は得られた磁気記録媒体の第１層の磁化状態
と第２層の状態を示す。FIG. 2 is a schematic sectional view for explaining the principle of the present invention, in which (a) shows formation of a first layer and its magnetic recording,
(B) shows the magnetization state by the formation of the second layer and the magnetic orientation, and (c) shows the magnetization state of the first layer and the state of the second layer of the obtained magnetic recording medium.
【図３】本発明の磁気記録媒体の他の構成を示す断面図
である。FIG. 3 is a cross-sectional view showing another configuration of the magnetic recording medium of the present invention.
【図４】本発明の磁気記録媒体の読み取りの原理を示す
図である。FIG. 4 is a diagram showing the principle of reading the magnetic recording medium of the present invention.
【図５】保磁力が２７５０エルステッドのバリウムフェ
ライトを第１の磁性層とし、また第２の磁性層としては
保磁力が２０エルステッド以下の高透磁率Ｆｅ−Ｓｉ合
金系の鱗片状磁性粉を厚さ１０μｍに塗布したときに、
第１の磁性層の残留磁束の値に対する第２の磁性層に形
成された識別信号の出力レベルの関係を示す図である。FIG. 5 shows barium ferrite having a coercive force of 2750 Oersted as the first magnetic layer, and the second magnetic layer is made of a scaly magnetic powder of high permeability Fe—Si alloy system having a coercive force of 20 Oersted or less. When applied to 10 μm,
It is a figure which shows the relationship of the output level of the identification signal formed in the 2nd magnetic layer with respect to the value of the residual magnetic flux of a 1st magnetic layer.
１：基体 ２：第１の磁性層 ３：第２の磁性層 ２１、２２：識別信号 ３１：高磁気出力部分 ３２：低磁気出力部分 1: Substrate 2: First magnetic layer 3: Second magnetic layer 21, 22: Identification signal 31: High magnetic output portion 32: Low magnetic output portion
【手続補正書】[Procedure amendment]
【提出日】平成６年８月１２日[Submission date] August 12, 1994
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】発明の名称[Name of item to be amended] Title of invention
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【発明の名称】 磁気記録媒体とその製造方法Title: Magnetic recording medium and method of manufacturing the same
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Name of item to be amended] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【特許請求の範囲】[Claims]
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００１[Correction target item name] 0001
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００１】[0001]
【産業上の利用分野】本発明は磁気記録媒体とその製造
方法に関するものであり、特に、金融、流通、交通、通
信などの代金決裁に用いられるなど高い機密性を求めら
れる磁気カードなどに適用する磁気記録媒体に関するも
のである。FIELD OF THE INVENTION The present invention relates to a magnetic recording medium and its manufacture.
The present invention relates to a method , and more particularly to a magnetic recording medium applied to a magnetic card or the like which is required to have high confidentiality such as used for payment decision of finance, distribution, transportation, communication and the like.
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００５[Name of item to be corrected] 0005
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００５】[0005]
【課題を解決するための手段】本発明は上記課題を解決
するために、非磁性基体の上の全体または一部に、２つ
以上の磁性層を積層してなる磁気記録媒体において、前
記磁性層の少なくとも１つの層をバインダ中に保磁力が
４００００ｅ以下の強磁性粉末を分散して構成し、他の
磁性層に記録された信号による磁界並びに配向磁界の影
響により形成された、書換不能な固定信号が記録されて
いることを特徴とする磁気記録媒体を提供する。前記少
なくとも１つの層に記録された書換不能な固定信号は、
媒体を識別するための情報である。このような書換不能
な固定信号は、特定の領域における単位面積あたりの磁
気出力が隣接する他の領域と異なることにより記録され
ることができる。また、このような書換不能な固定信号
は、特定の領域における単位体積あたりの磁性粒子の含
有率が隣接する他の領域と異なることにより記録される
ことができる。本発明はまた、上記の磁気記録媒体の製
造方法であって、先ず、非磁性基体上に磁気記録可能な
磁性材料から成る第１の磁性層を形成し、次いで前記第
１の磁性層に所定の信号を磁気記録し、その後保磁力が
４０００エルステッド以下の磁性体をバインダ中に分散
して作製した磁性塗料を塗布し、前記磁性塗料が乾燥固
化する前に、前記第１の磁性層の保磁力より低い磁界強
度で直流配向処理を施し、しかる後に前記磁性塗料を乾
燥固化することにより、第１の磁性層に記録された信号
による磁界並びに配向磁界の影響により形成された書換
不能な固定信号を第２の磁性層に形成することを特徴と
する磁気記録媒休の製造方法を提供する。In order to solve the above problems, the present invention provides a magnetic recording medium comprising two or more magnetic layers laminated on the whole or a part of a non-magnetic substrate. At least one of the layers is formed by dispersing a ferromagnetic powder having a coercive force of 40000e or less in a binder, and is formed by the influence of a magnetic field due to a signal recorded in another magnetic layer and an orientation magnetic field. Provided is a magnetic recording medium having a fixed signal recorded therein. The non-rewritable fixed signal recorded on the at least one layer is
This is information for identifying the medium. Such a non-rewritable fixed signal can be recorded because the magnetic output per unit area in a specific area is different from that in another adjacent area. In addition, such a non-rewritable fixed signal can be recorded because the content rate of the magnetic particles per unit volume in a specific area is different from that in other adjacent areas. The present invention also relates to the production of the above magnetic recording medium.
First, a magnetic recording is possible on a non-magnetic substrate.
Forming a first magnetic layer of a magnetic material, and then forming the first magnetic layer;
A predetermined signal is magnetically recorded on the first magnetic layer, and then the coercive force
Disperse magnetic material of 4000 oersted or less in binder
Apply the magnetic paint prepared by
The magnetic field strength lower than the coercive force of the first magnetic layer.
DC orientation treatment at a certain temperature, and then dry the magnetic paint.
The signal recorded on the first magnetic layer by drying and solidifying
Rewriting formed by the influence of the magnetic field and the orientation magnetic field due to
An impossible fixed signal is formed in the second magnetic layer.
A method of manufacturing a magnetic recording medium carrier is provided .
【手続補正書】[Procedure amendment]
【提出日】平成６年１２月１５日[Submission date] December 15, 1994
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Name of item to be amended] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００５[Name of item to be corrected] 0005
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００５】[0005]
【課題を解決するための手段】本発明は上記課題を解決
するために、非磁性基体の上の全体または一部に、２つ
以上の磁性層を積層してなる磁気記録媒体において、前
記磁性層の少なくとも１つの層をバインダ中に保磁力が
４００００ｅ以下の強磁性粉末を分散して構成し、他の
磁性層に記録された信号による磁界並びに配向磁界の影
響により形成された、書換不能な固定信号が記録されて
いることを特徴とする磁気記録媒体を提供する。前記少
なくとも１つの層に記録された書換不能な固定信号は、
媒体を識別するための情報である。このような書換不能
な固定信号は、特定の領域における単位面積あたりの磁
気出力が隣接する他の領域と異なることにより記録され
ることができる。また、このような書換不能な固定信号
は、特定の領域における単位体積あたりの磁性粒子の含
有率が隣接する他の領域と異なることにより記録される
ことができる。本発明はまた、上記の磁気記録媒体の製
造方法であって、先ず、非磁性基体上に磁気記録可能な
磁性材料から成る第１の磁性層を形成し、次いで前記第
１の磁性層に所定の信号を磁気記録し、その後保磁力が
４０００エルステッド以下の磁性体をバインダ中に分散
して作製した磁性塗料を塗布し、前記磁性塗料が乾燥固
化する前に、前記第１の磁性層の保磁力より低い磁界強
度で配向処理を施し、しかる後に前記磁性塗料を乾燥固
化することにより、第１の磁性層に記録された信号によ
る磁界並びに配向磁界の影響により形成された書換不能
な固定信号を第２の磁性層に形成することを特徴とする
磁気記録媒体の製造方法を提供する。In order to solve the above problems, the present invention provides a magnetic recording medium comprising two or more magnetic layers laminated on the whole or a part of a non-magnetic substrate. At least one of the layers is formed by dispersing a ferromagnetic powder having a coercive force of 40000e or less in a binder, and is formed by the influence of a magnetic field due to a signal recorded in another magnetic layer and an orientation magnetic field. Provided is a magnetic recording medium having a fixed signal recorded therein. The non-rewritable fixed signal recorded on the at least one layer is
This is information for identifying the medium. Such a non-rewritable fixed signal can be recorded because the magnetic output per unit area in a specific area is different from that in another adjacent area. In addition, such a non-rewritable fixed signal can be recorded because the content rate of the magnetic particles per unit volume in a specific area is different from that in other adjacent areas. The present invention also provides the above-described method for manufacturing a magnetic recording medium, which comprises first forming a first magnetic layer made of a magnetically recordable magnetic material on a non-magnetic substrate, and then forming a predetermined magnetic layer on the first magnetic layer. Signal is magnetically recorded, and then a magnetic coating material prepared by dispersing a magnetic material having a coercive force of 4000 oersted or less in a binder is applied. Before the magnetic coating material is dried and solidified, the first magnetic layer is protected. performing oriented treated with lower field strength than the magnetic force, by the magnetic coating and thereafter dried and solidified, the first magnetic field due to the signal recorded on the magnetic layer and non-rewritable fixed signal formed by the influence of the aligning magnetic field To form a second magnetic layer on the magnetic recording medium.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ０６Ｋ 19/10 Ｇ１１Ｂ 5/80 (72)発明者 狩野 智章 東京都台東区台東１丁目５番１号東京磁気 印刷株式会社内 (72)発明者 神田 悦史 東京都台東区台東１丁目５番１号東京磁気 印刷株式会社内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Reference number within the agency FI Technical display location G06K 19/10 G11B 5/80 (72) Inventor Tomoaki Kano 1-5-1 Taito, Taito-ku, Tokyo No. Tokyo Magnetic Printing Co., Ltd. (72) Inventor, Etsushi Kanda 1-5-1 Taito, Taito-ku, Tokyo Tokyo Magnetic Printing Co., Ltd.
Claims (4)
なくとも２つの磁性層を積層してなる磁気記録媒体にお
いて、 前記磁性層の少なくとも１つの磁性層はバインダ中に保
磁力が４０００Ｏｅ以下の磁性粒子を分散してなり、他
の磁性層に記録された信号による磁界並びに配向磁界の
影響により形成された、書換不能な固定信号が記録され
ていることを特徴とする磁気記録媒体。1. A magnetic recording medium comprising at least two magnetic layers laminated on the whole or a part of a non-magnetic substrate, wherein at least one magnetic layer has a coercive force of 4000 Oe or less in a binder. A magnetic recording medium having a non-rewritable fixed signal, which is formed by dispersing the magnetic particles of 1) and is formed by the influence of a magnetic field due to a signal recorded in another magnetic layer and an orientation magnetic field.
た書換不能な固定信号は、特定の領域における単位面積
あたりの磁気出力が隣接する他の領域と異なることによ
り形成されていることを特徴とする請求項１に記載の磁
気記録媒体。2. The non-rewritable fixed signal recorded in the at least one magnetic layer is formed by a magnetic output per unit area in a specific region being different from that in another adjacent region. The magnetic recording medium according to claim 1.
た書換不能な固定信号は、特定の領域における単位体積
あたりの磁性粒子の含有率が隣接する他の領域と異なる
ことにより形成されていることを特徴とする請求項１又
は２に記載の磁気記録媒体。3. The non-rewritable fixed signal recorded in the at least one magnetic layer is formed when the content ratio of magnetic particles per unit volume in a specific region is different from that in other adjacent regions. The magnetic recording medium according to claim 1 or 2.
た書換不能な固定信号は、媒体を識別するための情報で
あることを特徴とする請求項１ないし３のいずれかに記
載の磁気記録媒体。4. The magnetic recording medium according to claim 1, wherein the non-rewritable fixed signal recorded on the at least one magnetic layer is information for identifying the medium. .
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06011319A JP3121977B2 (en) | 1994-01-06 | 1994-01-06 | Magnetic recording medium and manufacturing method thereof |
| US08/356,431 US5643686A (en) | 1994-01-06 | 1994-12-15 | Magnetic recording medium and method for manufacturing the same |
| KR1019950000088A KR0176732B1 (en) | 1994-01-06 | 1995-01-05 | Magnetic recording medium and method for manufacturing the same |
| CN95100607A CN1075220C (en) | 1994-01-06 | 1995-01-06 | Magnetic recording medium and method for manufacturing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06011319A JP3121977B2 (en) | 1994-01-06 | 1994-01-06 | Magnetic recording medium and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07210859A true JPH07210859A (en) | 1995-08-11 |
| JP3121977B2 JP3121977B2 (en) | 2001-01-09 |
Family
ID=11774711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06011319A Expired - Fee Related JP3121977B2 (en) | 1994-01-06 | 1994-01-06 | Magnetic recording medium and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3121977B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997039443A1 (en) * | 1996-04-16 | 1997-10-23 | Kabusiki Kaisya I.C.M. | Magnetic recording medium and method for magnetic signal writing thereof |
| WO1997044783A1 (en) * | 1996-05-23 | 1997-11-27 | Kabushiki Kaisha I.C.M. | Magnetic recording medium |
| JP2011028217A (en) * | 2009-03-24 | 2011-02-10 | Fuji Xerox Co Ltd | Annular body, cartridge, and image forming apparatus |
| US8355223B2 (en) * | 2008-09-12 | 2013-01-15 | Showa Denko K.K. | Magnetic recording medium, method of manufacturing magnetic recording medium, and magnetic recording/reproducing apparatus |
-
1994
- 1994-01-06 JP JP06011319A patent/JP3121977B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997039443A1 (en) * | 1996-04-16 | 1997-10-23 | Kabusiki Kaisya I.C.M. | Magnetic recording medium and method for magnetic signal writing thereof |
| WO1997044783A1 (en) * | 1996-05-23 | 1997-11-27 | Kabushiki Kaisha I.C.M. | Magnetic recording medium |
| US8355223B2 (en) * | 2008-09-12 | 2013-01-15 | Showa Denko K.K. | Magnetic recording medium, method of manufacturing magnetic recording medium, and magnetic recording/reproducing apparatus |
| JP2011028217A (en) * | 2009-03-24 | 2011-02-10 | Fuji Xerox Co Ltd | Annular body, cartridge, and image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3121977B2 (en) | 2001-01-09 |
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