JPH0458642B2 - - Google Patents
Info
- Publication number
- JPH0458642B2 JPH0458642B2 JP59267663A JP26766384A JPH0458642B2 JP H0458642 B2 JPH0458642 B2 JP H0458642B2 JP 59267663 A JP59267663 A JP 59267663A JP 26766384 A JP26766384 A JP 26766384A JP H0458642 B2 JPH0458642 B2 JP H0458642B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic recording
- recording layer
- track
- parts
- 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.)
- Expired - Lifetime
Links
- 238000012795 verification Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 7
- 239000000696 magnetic material Substances 0.000 claims description 6
- 230000004907 flux Effects 0.000 claims description 5
- 239000010410 layer Substances 0.000 description 25
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 15
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 12
- 239000003973 paint Substances 0.000 description 7
- 239000011241 protective layer Substances 0.000 description 7
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 6
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 6
- 239000002994 raw material Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 238000002156 mixing Methods 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 3
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 3
- 229920006026 co-polymeric resin Polymers 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000004831 Hot glue Substances 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007756 gravure coating Methods 0.000 description 2
- 239000012948 isocyanate Substances 0.000 description 2
- 150000002513 isocyanates Chemical class 0.000 description 2
- 229920001225 polyester resin Polymers 0.000 description 2
- 239000004645 polyester resin Substances 0.000 description 2
- 229920003225 polyurethane elastomer Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229920002160 Celluloid Polymers 0.000 description 1
- MBHRHUJRKGNOKX-UHFFFAOYSA-N [(4,6-diamino-1,3,5-triazin-2-yl)amino]methanol Chemical compound NC1=NC(N)=NC(NCO)=N1 MBHRHUJRKGNOKX-UHFFFAOYSA-N 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000012943 hotmelt Substances 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000013008 moisture curing Methods 0.000 description 1
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
Description
発明の目的 Purpose of invention
本発明は、真偽の判別が容易であつて、偽造が
困難な磁気記録媒体をもつカード類の記録方法に
関する。
TECHNICAL FIELD The present invention relates to a recording method for cards having magnetic recording media whose authenticity can be easily determined and which is difficult to counterfeit.
近年、磁気記録媒体をもつカード類の普及は著
しく、キヤツシユカード、銀行通帳をはじめ、ク
レジツトカード、乗車券、回数券、定期券など、
広い範囲で利用されている。こうした磁気カード
類の普及につれて、磁気カード類を偽造または複
製して悪用する者があらわれ、その防止とカード
類の真偽を適確に判別する技術が要求されてい
る。
In recent years, cards with magnetic recording media have become extremely popular, including cash cards, bank passbooks, credit cards, train tickets, coupon tickets, commuter passes, etc.
It is used in a wide range of areas. As magnetic cards become more widespread, there are people who misuse magnetic cards by forging or duplicating them, and there is a need for technology to prevent this and to accurately determine the authenticity of cards.
本発明の目的は、上記の要求にこたえ、偽造を
効果的に防止するとともに、偽造されても真偽を
容易に判別し、偽カードを排除できるような磁気
記録媒体をもつカード類の記録方法を提供するこ
とにある。
発明の構成
An object of the present invention is to meet the above requirements and to effectively prevent counterfeiting, and even if a card is counterfeited, it is easy to determine whether it is genuine or not, and to eliminate counterfeit cards. Our goal is to provide the following. Composition of the invention
図面を参照して説明すれば、本発明で使用する
磁気記録媒体をもつカード類は、第１図および第
２図に示すような基材１の上に磁気記録層２を有
するカード類において、磁気記録層の磁気特性が
読みとり方向に不連続に変化するもの、代表的に
は第２図に示すように、磁性材料の量が不連続に
変化するものであつて、これに情報用トラツクと
照合用トラツクとを設け、情報用トラツクに情報
を書き込み、照合用トラツクを直流消去して読み
とり、磁気特性の不連続な変化、代表的には磁束
の変化を知ることによつて、カードの真偽を判別
した上で情報を処理することを特徴とする。
To explain with reference to the drawings, cards having a magnetic recording medium used in the present invention include cards having a magnetic recording layer 2 on a base material 1 as shown in FIGS. 1 and 2. The magnetic properties of the magnetic recording layer change discontinuously in the reading direction, typically the amount of magnetic material changes discontinuously as shown in Figure 2. A verification track is provided, information is written on the information track, the verification track is erased with DC current and read, and the authenticity of the card is determined by detecting discontinuous changes in magnetic properties, typically changes in magnetic flux. It is characterized by processing information after determining whether it is false.
照合用トラツクを直流消去することは、磁性材
料を一様に磁化させることにほかならないから、
第２図に示すように磁性材料の量が不連続に変化
していれば、読みとつて行つたときに、その変化
する位置において磁束が急激に変化する結果、出
力として第３図に示したようなパルスが発生す
る。このパルスの位置を標準のデータと照合する
ことにによつて、カードの真偽を判別し、偽カー
ドは排除する。
Erasing the verification track with direct current is nothing but uniformly magnetizing the magnetic material.
If the amount of magnetic material changes discontinuously as shown in Figure 2, when reading it, the magnetic flux will change rapidly at the position where it changes, resulting in the output shown in Figure 3. A pulse like this is generated. By comparing the position of this pulse with standard data, the authenticity of the card is determined, and fake cards are eliminated.
本発明で「カード類」とは、キヤツシユカード
やクレジツトカードに限らず乗車券や回数券、預
金通帳を含む意味である。
「記録」とは、上述したところから明らかなよ
うに、磁気記録層への書き込み、読出しの両方を
包含する語である。
磁気記録層には、常用のコバルト被着ガンマ酸
化鉄そのほか、任意の磁性材料を、適宜のバイン
ダーとともに使用する。
磁気記録層の耐摩耗性を必要とする場合は、そ
の上に保護層３を設ける。
磁気記録層をつくるには、磁性材料を含有する
インキの印刷によるのがよい。代表的な例として
は、第２図に示すように、低抗磁力磁気記録層２
Ａのベタ印刷と高抗磁力磁気記録層２Ｂのパート
印刷との組み合わせである。もちろんこの逆の組
み合わせでもよいし、同一抗磁力材料の組み合わ
せでもよい。このような磁気記録層に基材に合体
させる手段の代表的なものは、以下に実施例を示
す熱転写であるが、もちろんそのほかの手段によ
つてもよい。
使用に当つては、情報を読みとつた後、照合用
トラツクを交流消去することが好ましい。交流消
去すれば磁化はゼロになるから、読みとりに対し
て何の出力もあらわれない。つまり、磁気記録層
の磁気特性の不連続な変化が判別不可能となり、
偽造を防止できる。
In the present invention, "cards" is not limited to cash cards and credit cards, but also includes train tickets, coupon tickets, and bankbooks. As is clear from the above, the term "recording" includes both writing to and reading from the magnetic recording layer. For the magnetic recording layer, in addition to the commonly used cobalt-coated gamma iron oxide, any other magnetic material is used together with a suitable binder. If the magnetic recording layer requires wear resistance, a protective layer 3 is provided thereon. The magnetic recording layer is preferably produced by printing with an ink containing a magnetic material. As a typical example, as shown in FIG. 2, a low coercive force magnetic recording layer 2
This is a combination of the solid printing of A and the part printing of the high coercive force magnetic recording layer 2B. Of course, the reverse combination may be used, or a combination of the same coercive materials may be used. A typical means for integrating such a magnetic recording layer with a base material is thermal transfer, which will be shown in the following embodiments, but of course other means may also be used. In use, it is preferable to erase the verification track after reading the information. If the AC is erased, the magnetization becomes zero, so no output will appear in the reading. In other words, it becomes impossible to discern discontinuous changes in the magnetic properties of the magnetic recording layer.
Counterfeiting can be prevented.
下記の原料を配合して（「部」はいずれも重量
部）、剥離材を調製した。
酢酸セルロース樹脂（大日本セルロイド） ５部
メチロールメラミン系熱硬化性樹脂（日本カー
バイド） １部
メチルエチルケトン 50部
メチルアルコール 25部
トルエン 25部
厚さ25μのポリエステルのベースフイルム上
に、上記の剥離材をグラビアコートし厚さ1μの
剥離層を形成した。
次に、下記の原料を配合して、保護層用塗料を
調整した。
ポリビニルブチラール樹脂「エスレツクBX」
（積水化学） ３部
湿気硬化型ウレタン樹脂「オレスターM95−
50A」（三井東圧） ３部
メチルエチルケトン 30部
トルエン 30部
酢酸エチル 30部
磁気の保護層用塗料を剥離層上にグラビアコー
トし、厚さ1μの保護層を形成した。
下記の原料を配合し、低抗磁力磁性塗料を調製
した。
γ−Fe2O3（Hc＝300Oe） 70部
部分ケン化塩化ビニル／酢酸ビニル共重合樹脂
「ビニライトVAGH」（UCC） 15部
ポリウレタンエラストマー樹脂「サンブレン
IB114B」（三洋化成工業） 30部
線状飽和ポリエステル樹脂「バイロン
RV53SS」（東洋紡） 15部
イソプロピルアルコール 50部
メチルエチルケトン 50部
トルエン 50部
イソシアネート系硬化剤「ATマイテツクNY
−220A」（三菱化成） ３部
上記の低抗磁力磁性塗料をグラビアコート法に
より保護層上に全面コーテイングし、低抗磁力磁
気記録層２Ａを形成した。
下記の原料を配合して、高抗磁力磁性塗料を調
製した。
BaO−6Fe2O3（Hc＝3000Oe） 70部
部分ケン化塩化ビニル／酢酸ビニル 共重合樹
脂「ビニライトVAGH」（UCC） ５部
ポリウレタンエラストマー樹脂「サンブレン
IB114B」（三洋化成工業） 40部
線状飽和ポリエステル樹脂「バイロン
RV53SS」（東洋紡） 20部
イソプロピルアルコール 50部
メチルエチルケトン 50部
トルエン 50部
イソシアネート系硬化剤「ATマイテツクNY
−220A」（三菱化成） ３部
上記の高抗磁力磁性塗料を、グラビアコート法
により、低抗磁力磁気記録層２Ａ上に所定のパタ
ーンでコーテイングして、高抗磁力磁気記録層２
Ｂを形成した。
下記の原料を配合して、ホツトメルト接着剤塗
料を調製した。
塩化ビニル／酢酸ビニル共重合樹脂「デンカラ
ツク721」（電気化学） １部
アクリル樹脂 ２部
トルエン ８部
酢酸エチル ８部
上記のホツトメルト接着剤塗料を磁気記録層上
に、グラビアコート、厚さ10μのホツトメルト接
着層を形成した。
以上の順序で形成した転写シートを6.5mm幅に
スリツトし、カード基材に用いる厚さ100μのポ
リ塩化ビニルシートの所定の位置に熱転写し、ベ
ースフイルムであるポリエステルフイルムを剥離
した。こうして用意した磁気記録層つきのオーバ
ーシートに、ポリ塩化ビニルのセンターコア（厚
さ560μ）と、やはりポリ塩化ビニルのオーバー
シート（厚さ100μ）とをこの順に重ね、150℃、
25Kg／cm2の条件で加熱加圧して積層し、仕上げ、
打抜きを行ない、縦86mm、幅54mm、厚さ0.76mmの
カードを得た。
このように製造した磁気記録媒体をもつカード
の情報トラツクに情報を書き込み、照合用トラツ
クを直流消去して読みとつた。磁気記録層２の残
留磁束の読みとり方向における不連続な変化に応
じて、第３図に示すようなパルス出力が得られ
た。情報の読み出しには支障はなかつた。
なお、保護層と磁気記録層の間に着色層を設け
てもよいし、着色層と磁気記録層の間に、蒸着層
を設けてもよい。
考案の効果
本発明の磁気記録方法によれば、容易にカード
の真偽を判別し、偽カードを排除できる。真の情
報を読みとつた後、照合用トラツクを交流消去し
ておけば、照合用トラツクにおける磁気記録層の
構造がわからないから、偽造はいつそう困難であ
る。
A release material was prepared by blending the following raw materials (all parts are by weight). Cellulose acetate resin (Dainippon Celluloid) 5 parts Methylolmelamine thermosetting resin (Nippon Carbide) 1 part Methyl ethyl ketone 50 parts Methyl alcohol 25 parts Toluene 25 parts Gravure the above release material onto a 25μ thick polyester base film. A release layer with a thickness of 1 μm was formed by coating. Next, the following raw materials were blended to prepare a coating for a protective layer. Polyvinyl butyral resin “Eslec BX”
(Sekisui Chemical) 3-part moisture-curing urethane resin "Orestar M95-
50A'' (Mitsui Toatsu) 3 parts methyl ethyl ketone 30 parts toluene 30 parts ethyl acetate 30 parts Magnetic protective layer paint was gravure coated on the release layer to form a 1μ thick protective layer. A low coercive force magnetic paint was prepared by blending the following raw materials. γ-Fe 2 O 3 (Hc=300Oe) 70 parts Partially saponified vinyl chloride/vinyl acetate copolymer resin "Vinyrite VAGH" (UCC) 15 parts Polyurethane elastomer resin "Sunbren"
IB114B” (Sanyo Chemical Industries) 30 parts linear saturated polyester resin “Vylon
RV53SS” (Toyobo) 15 parts Isopropyl alcohol 50 parts Methyl ethyl ketone 50 parts Toluene 50 parts Isocyanate hardening agent “AT Mitech NY
-220A'' (Mitsubishi Kasei) 3 parts The above low coercive force magnetic paint was coated on the entire surface of the protective layer by gravure coating to form a low coercive force magnetic recording layer 2A. A high coercive force magnetic paint was prepared by blending the following raw materials. BaO−6Fe 2 O 3 (Hc=3000Oe) 70 parts Partially saponified vinyl chloride/vinyl acetate copolymer resin "Vinyrite VAGH" (UCC) 5 parts Polyurethane elastomer resin "Sunblen"
IB114B” (Sanyo Chemical Industries) 40 parts linear saturated polyester resin “Vylon
RV53SS” (Toyobo) 20 parts Isopropyl alcohol 50 parts Methyl ethyl ketone 50 parts Toluene 50 parts Isocyanate hardening agent “AT Mitech NY
-220A'' (Mitsubishi Kasei) Part 3 The high coercive force magnetic paint is coated in a predetermined pattern on the low coercive force magnetic recording layer 2A by gravure coating method, and the high coercive force magnetic recording layer 2
B was formed. A hot melt adhesive paint was prepared by blending the following raw materials. Vinyl chloride/vinyl acetate copolymer resin "Denkaratsuku 721" (Electrochemical) 1 part acrylic resin 2 parts toluene 8 parts ethyl acetate 8 parts The above hot melt adhesive paint was applied onto the magnetic recording layer, gravure coated, and a 10μ thick hot melt was applied. An adhesive layer was formed. The transfer sheet formed in the above order was slit to a width of 6.5 mm and thermally transferred to a predetermined position on a 100 μm thick polyvinyl chloride sheet used as a card base material, and the polyester film serving as the base film was peeled off. A polyvinyl chloride center core (thickness: 560 μm) and a polyvinyl chloride oversheet (thickness: 100 μm) were layered in this order on the oversheet with the magnetic recording layer prepared in this way, and heated at 150°C.
Laminated under heat and pressure under conditions of 25Kg/ cm2 , finished,
A card with a length of 86 mm, a width of 54 mm, and a thickness of 0.76 mm was obtained by punching. Information was written on the information track of the card having the magnetic recording medium manufactured in this way, and the verification track was erased with direct current to read it. In response to discontinuous changes in the residual magnetic flux of the magnetic recording layer 2 in the reading direction, a pulse output as shown in FIG. 3 was obtained. There was no problem in reading information. Note that a colored layer may be provided between the protective layer and the magnetic recording layer, or a vapor deposited layer may be provided between the colored layer and the magnetic recording layer. Effects of the Invention According to the magnetic recording method of the present invention, it is possible to easily determine the authenticity of a card and eliminate fake cards. If the verification track is erased with alternating current after reading the true information, the structure of the magnetic recording layer in the verification track will not be known, making counterfeiting very difficult.
第１図は、本発明の磁気記録方法に使用するカ
ード類の一部分を示す平面図である。第２図は、
第１図−方向の断面図である。第３図は、磁
束の変化にともなうパルス出力を第１図および第
２図に対応させて示す図である。
１……基材、２……磁気記録層、３……保護
層、４……照合用トラツク。
FIG. 1 is a plan view showing a portion of cards used in the magnetic recording method of the present invention. Figure 2 shows
FIG. 1 is a sectional view in the direction of FIG. 1; FIG. 3 is a diagram corresponding to FIGS. 1 and 2, showing pulse outputs as a result of changes in magnetic flux. DESCRIPTION OF SYMBOLS 1... Base material, 2... Magnetic recording layer, 3... Protective layer, 4... Collation track.
Claims (1)
であつて、磁気記録層の磁気特性が読みとり方向
に不連続に変化するものに情報用トラツクと照合
用トラツク４とを設け、情報用トラツクに情報を
書き込み、照合用トラツク４を直流消去して読み
とり、磁気特性の不連続な変化を知ることによつ
てカードの真偽を判別した上で情報を処理するこ
とを特徴とする磁気記録媒体をもつカード類の記
録方法。 ２ 磁気特性の不連続な変化が磁気記録層を形成
する磁性材料の量の不連続な変化によつてもたら
されたものであり、その変化が磁束の変化として
測定されるものである特許請求の範囲第１項の記
録方法。 ３ 読みとりの後に照合用トラツクを交流消去し
ておくことを含む特許請求の範囲第１項の記録方
法。[Scope of Claims] 1 Cards having a magnetic recording layer 2 on a base material 1, in which the magnetic properties of the magnetic recording layer change discontinuously in the reading direction, include an information track and a verification track 4. write information on the information track, read the verification track 4 by erasing it with direct current, determine the authenticity of the card by knowing discontinuous changes in magnetic characteristics, and then process the information. A recording method for cards having a magnetic recording medium characterized by: 2. A patent claim in which the discontinuous change in magnetic properties is caused by a discontinuous change in the amount of magnetic material forming the magnetic recording layer, and the change is measured as a change in magnetic flux. Recording method in item 1 of the scope. 3. The recording method according to claim 1, which includes erasing the collation track after reading.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59267663A JPS61145702A (en) | 1984-12-19 | 1984-12-19 | Recording method for card or the like containing magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59267663A JPS61145702A (en) | 1984-12-19 | 1984-12-19 | Recording method for card or the like containing magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61145702A JPS61145702A (en) | 1986-07-03 |
| JPH0458642B2 true JPH0458642B2 (en) | 1992-09-18 |
Family
ID=17447803
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59267663A Granted JPS61145702A (en) | 1984-12-19 | 1984-12-19 | Recording method for card or the like containing magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61145702A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63194991A (en) * | 1987-02-09 | 1988-08-12 | 有限会社ビタ | Magnetic card |
-
1984
- 1984-12-19 JP JP59267663A patent/JPS61145702A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61145702A (en) | 1986-07-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5972438A (en) | Magnetic recording medium and method of manufacture of same | |
| JP3198184B2 (en) | Plastic card with magnetic stripe | |
| JPH0630960B2 (en) | Thermal magnetic recording medium | |
| JPH0533460B2 (en) | ||
| JPS6213394A (en) | Card | |
| JPS5891531A (en) | Document provided with magnetic stripe | |
| JPH0519845Y2 (en) | ||
| JPH0458642B2 (en) | ||
| JPH0512067Y2 (en) | ||
| JP2626858B2 (en) | Manufacturing method of magnetic recording medium | |
| JPH0512068Y2 (en) | ||
| JPS6321274B2 (en) | ||
| JPH0250528B2 (en) | ||
| JP3125934B2 (en) | Magnetic recording media | |
| JPS61198465A (en) | Method for writing and reading card or the like having magnetic recording medium | |
| JP2706714B2 (en) | Magnetic recording medium and manufacturing method thereof | |
| JPS5847530Y2 (en) | magnetic recording medium | |
| JP2001319318A (en) | Magnetic recording medium | |
| JP4012334B2 (en) | Magnetic recording medium and method for manufacturing the same | |
| JP2636542B2 (en) | Magnetic recording medium and information reading method thereof | |
| JP4068762B2 (en) | Magnetic recording medium and method for manufacturing the same | |
| JP4095203B2 (en) | Magnetic recording medium and method for manufacturing the same | |
| JP2649756B2 (en) | Magnetic recording medium and method of manufacturing the same | |
| JP4028661B2 (en) | Magnetic recording medium and method for manufacturing the same | |
| JPH06338051A (en) | Magnetic recording medium and its production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |