CA1185368A - Magnetic tape cassette with color change type excess temperature indicator - Google Patents
Magnetic tape cassette with color change type excess temperature indicatorInfo
- Publication number
- CA1185368A CA1185368A CA000400854A CA400854A CA1185368A CA 1185368 A CA1185368 A CA 1185368A CA 000400854 A CA000400854 A CA 000400854A CA 400854 A CA400854 A CA 400854A CA 1185368 A CA1185368 A CA 1185368A
- Authority
- CA
- Canada
- Prior art keywords
- cassette
- temperature
- magnetic tape
- sensitive material
- reversible
- 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
Links
Landscapes
- Paints Or Removers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A magnetic tape cassette includes a temperature indicating member which is bonded to a surface of a cassette half or included in the material of the cassette itself. The temperature sensitive material may be formed of a reversible temperature indicating material such as Ag2HgI4, Cu2HgI4, or a mixture thereof. The temperature sensitive material may also be a non-reversible temperature moderating pigment such as Cu(Pyr)2 or non-reversible thermopaints.
A magnetic tape cassette includes a temperature indicating member which is bonded to a surface of a cassette half or included in the material of the cassette itself. The temperature sensitive material may be formed of a reversible temperature indicating material such as Ag2HgI4, Cu2HgI4, or a mixture thereof. The temperature sensitive material may also be a non-reversible temperature moderating pigment such as Cu(Pyr)2 or non-reversible thermopaints.
Description
~s~
L BA_GRO~JND OF T~:IE INVENTION
This invention relates to magne-tic tape cassettes.
In general, a signal recording and reproduclng magnetic tape is wound, in endless form or in reel form, on 5 reels and is incorporated in a plastic case, so that the magnetic tape is protected from the touch of an external member or hands as much as possible except when the case is loaded in a signal recording or xeproducing device.
The aforementioned case is fabricated by combining a pair of upper and lower half cases, and is called a cassette. Depending on the uses and sizes, cassettes are divided into compact cassettes, microcassettes, video cassettes, etc.
The cassette is excellent in portability and mobility, and can be stored stably in an atmosphere in which the temperature and humidity are variable to some extent.
The ranges of temperature and humidity which the cassette undergoes during storage or the use have increased with new and varied uses of cassettes. Among temperature and humidity, the former seriously affects the cassette and the magnetic tape. Therefore, it is essential to provide a countermeasure against temperature.
At excessively high temperatures the cassette may be permanently deformed and the magnetic characteristics of the tape may deteriorate. When the magnetic tape is heated, the output level of the recorded signals will de-crease. Such a phenomenon is called "heat demagnetization".
Also, if the magnetic tape when wound in reel form is heated, recorded signals which are recorded at a high level on the ^. .~ 1 --;i36;1!~
tape are transferxed to or traced over the other portion of the tape which is wound inside or outside the portion having the high level of recorded signals thereon. As a result, when the signals are being reproduced, the transferred signal will adversely affect the reproduction of the original sig-nals. In the case of a magnetic tape employing a denatured cobalt magnetic material, the coercive force Hc thereof is dependent upon temperature and if the tape is excessively heated, the anti-magnetic force thereof is lowered and the high frequency characteristic thereof deteriorates. When the magnetic tape is provided with a support base of poly-ethylene terephthalate (PET) excessive heat can cause the tape to shrink longitudinally. Therefore, excessive heat can adversely a~fect a magnetic tape cassette in a number ; 15 of ways which would render the tape cassette substantially useless.
A conventional cassette cannot in~orm the user of the occurrence oE such problems vi~ually directly (or through color change) so that the user can take countermeasures.
Furthermore,- the conventional cassette cannot inform the user of the range of usage temperatures through color change.
~UMMARY OF THE INV~NTION
Accordingly, the object of this invention is to provide a magnetic tape cassette in which the abo~e-described v 25 difficulties are eliminate, so that the magnetic tape can be stably stored and used.
The foregoiny object and other objects of the invention have been achieved by the provision of a magnetic ..
,., ,~ .
1 cassette -tape which includes a temperature indicating member which is bonded to a surface of a cassette half or included in the half ~tself.
BRIEF DESCRIPTION OF THE DRAWINGS
.
Fig. 1 is a plan view of a magnetic tape cassette according to this invention; and Fig. 2 is a sectional view showing essential components of the cassette according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 is a plan view showing one example of a magnetic tape cassette according to one embodiment of the invention, for recording and reproducing audio slgnals.
The cassette has a temperature indicating member 6 which is bonded to a corner of the upper surface 2 of a half 1 : 15 which is relatively flat e~cept for a pair of hub holes 3 and 4 and a window member S.
The temperature indicating member 6, as shown in Fig. 2, comprises a support 7 and a film layer 8 formed on the surface of the support 7 by coating with a coating solution which is prepared by dispersing temperature in dicating pigment in a binder. The temperature indicating member 6 is bonded to the upper surface 2 with an adhesive which is suitably determined from the relation between the materials of the half 1 and the support 7.
The temperature indicating pigment may be of the reversible or non-reversible type, and the grain size rnay preferably be 30 ~ or less, ~l8S36~
1 Examples of suitable reversible temperature indicating pigments are Ag2HgI4, Cu2HyI4, and a solid solution of the mixture of Ag2HgI4 and Cu2HgI4. "Reversible thermopaints" R-4, R-5, R-6, R-7, R-13, R-15 and R-17 manufactured by Rikagaku Kenkyusho are commercially available for use as such reversible temperature indicating pigments.
- 3a -~15~
The properties of the "reversible thermopaints" are as indicated in the following table:
Table 1 color High Low temperature changetemperature - No. color temperature color Remarks R-4Reddish yellow 40C ReddishOrange at about orange 35C
R-5 Yellow 50C Yellowish Reddish yellow orange at about 45C
R-6 Bright 60C Dark brown- Dark red at about yellowish red purple 55C
R-7 Red 70C Dark brown- Dark red at about purple 60C
R-13 Yellow 130C Yellow-orange R-15Lemon-yellow- 150C Yellow green R-17 - Lemon-yellow- 170C Yellow green Examples of suitable non-reversible temperature indicat-ing pigments are [Cu~Pyr)2] ~CNsJ2~ CoI2 2C6H12N4 1OH2O, [Cr~NH3)5Cl]Cz04, NiC12-2C6H12N4rlOH20, 2PbC03~Pb~OH32, CoKP04-H O CdCO NH4VO3, NH4MnP2O7 and Cd~OH)2.
thermopaints #S, ~-7, #8, #9, #11, #13, #14, #16, #18, #20, #22, #25, #27, #29, #31, #33, #36, #41, #44 and #45 manufactured 10- by Rikagaku Kenkyusho are commercially available for use as such non-reversible temperature indicating pigments.
53~8 The properties of the "non-reversible ther~opaints"
are as indicated in Table 2:
i3~;8 Table 2 color Original change No. color temperature Change color Remarks SPale Pink 50C Bright blue 7Pale Pink 70C Pale purple 8. Pale Pink 80C Bright purple 9 Pinlc white 90C Bright purple 11 Pale green 110C Bright bluish Yellowish gray purple at about 70C
13 Purplish 130C Dim bluish pink purple 14 Bluish green 140¢ Pale red-purple 16 Bright 160C Gray-black greenish blue 18 Red-purple 180C Brown-black 20 Pale yellow- 200C Bright bluish orange purple .:
22 White 220C Gray-black Pale pink at about 25 Pale yellow- 250C Bright brown Pale yellow-brown green at about 210C
27 Pale yellow- 270C Pale blue-orange purple 29 Pale pink 290C Black ~ale purple at about 170C
31 Bright blu- 310C Brown black ish gray color Original change No. colortemperature Change color Remarks 33 Pale blue~ 330C Gray-black green 36 White 360C Orange Gray-white at about 290C
41 Blue 410C Brown white 44 White 440C Pale yellow- Bluish white at brown about 210C and bluish black at about 310C
Purple 450C White For the reversible temperature indicating pigments mentioned above, methyl methacrylate-vinyl acetate (1 : 1) - copolymer resin varnish is preferably employed as the binder.
For the non-reversible temperature indicating pigments, ethyl cellulose lacquer is preferably employed as the binder in the case where the color change temperature is 200C or below9 and silicone varnish is preferably employed as the binder in the case where the color change temperature is 200C or higher.
Examples of the above-described support are a plastic sheet of polyethyline terephthalate, cellulose triacetate, vinyl chloride, polycarbonate or the like; paper, synthetic paper, metal foil or the like.
As is apparent from the above description, in the cassette according to the invention, a temperature indicating member 6 whose color is freely changed by the ambient temper-3~
ature is bonded to the upper surface 2 of the half 1, which can be readily seen. Therefore, the deformation of the cassette and deterioration in the magnetic characteristic of the magnetic tape therein due to overheating of the cassette can be detected early. Thus, the cassette can be used at any place and under any operating condition.
It is often impossible to observe the temperature indicating member when the cassette is stored; however, the highest temperature the cassette has been exposed to can be detected later. Similarly, in the case where it is--impossible to observe the temperature indicating member during the use of the cassette, the highest temperature the cassette has under-gone can be detected later by merely observing the color change.
In the case of Fig. 1, only one temperature indicating member 6 is bonded to the surface of the cassette; however, a plurality of temperature indicating members may be bonded to the surface, for example at differing temperature character-istics, or the temperature indicating members may be bonded to both the "A" surface and/or the "B" sur-face of the cassette ~alf.
In the temperature indicating member shown in Fig. 2, the film layer 8 is formed on the support 7; however, the i,nvention is not limited thereto or thereby. That is~ the aforementioned pigment may be mixed with the material which forms the half 1. The same effect can be obtained by directly 53~
coating the surface of the hal-f with the "thermopaint".
The novel effects of the cassette will be clarified by describing a number of concrete examples.
Example 1 , The following materials were kneaded by allowing them to pass through two heated rolls:
Styrol resin (manufactured by Asahi Dau Co.) for fabricating a cassette: 100 parts by wt.
Cu2HgI4 (average particle size 4 ~): 2 parts by wt.
The resultant red mixture was melted by heat, to mold a cassette half, and a complete cassette half was prepared by incorporating a magnetic tape therein. The cassette half was placed on the dash board of a vehicle in the sun, with the windows closed. In forty minutes after the casstte half was placed, it was observed that the color had changed from red into brown-purple. In this case, the surface temperature of the dash board was 67C. Judging from the properties of the tem-perature indicating pigment Cu2HgI4, the color change into brown-purple meant that the surface temperature of the cassette half zo had exceeded 70C.
Example 2 The cassette half was coated with reversible thermo-paint ~7 manufactured by Rikagaku Kenkyusho and held at a S3~
sunny place in a vehicle. In forty minutes, it was observed that the color had changed from pale pink into pale purple.
The temperature in the vehicle was 67C in this experiment.
Concrete Example 3 The reversible thermopaint #7 manu-factured by the Rikagaku Kenkyusho was applied to a PET base 23 ~ in thickness, or the support, to a thickness of lS ~, to prepare the temper-ature indicating member. The temperature indicating member thus prepared was bonded to the cassette half, and the cassette half was held at a sunny place in the vehicle. In forty minutes, it was observed that the color was changed from pale pink into pale purple. In this experiment, the temperature in the vehicle was 67C
Concrete ~xample 4 A non-reversible temperature indicating pigment CoKPO4 H2O and ethyl cellulose lacquer were mixed in the ratio 1 : 1, and the resultant mixture was applied to an ordinary cassette half. After being dried, the cassette was placed in a constant temperature oven in an atmosphere of 150C. In ten minutes, it was observed that the color was changed from rose to blue.
At the same time, the cassette half was taken out of the constant temperature oven, and it was found that the cassette half was deformed. Judging from the properties of the pigment used, the S
color change to blue meant that the cassette half was subjected to a temperature of 140C or higher.
L BA_GRO~JND OF T~:IE INVENTION
This invention relates to magne-tic tape cassettes.
In general, a signal recording and reproduclng magnetic tape is wound, in endless form or in reel form, on 5 reels and is incorporated in a plastic case, so that the magnetic tape is protected from the touch of an external member or hands as much as possible except when the case is loaded in a signal recording or xeproducing device.
The aforementioned case is fabricated by combining a pair of upper and lower half cases, and is called a cassette. Depending on the uses and sizes, cassettes are divided into compact cassettes, microcassettes, video cassettes, etc.
The cassette is excellent in portability and mobility, and can be stored stably in an atmosphere in which the temperature and humidity are variable to some extent.
The ranges of temperature and humidity which the cassette undergoes during storage or the use have increased with new and varied uses of cassettes. Among temperature and humidity, the former seriously affects the cassette and the magnetic tape. Therefore, it is essential to provide a countermeasure against temperature.
At excessively high temperatures the cassette may be permanently deformed and the magnetic characteristics of the tape may deteriorate. When the magnetic tape is heated, the output level of the recorded signals will de-crease. Such a phenomenon is called "heat demagnetization".
Also, if the magnetic tape when wound in reel form is heated, recorded signals which are recorded at a high level on the ^. .~ 1 --;i36;1!~
tape are transferxed to or traced over the other portion of the tape which is wound inside or outside the portion having the high level of recorded signals thereon. As a result, when the signals are being reproduced, the transferred signal will adversely affect the reproduction of the original sig-nals. In the case of a magnetic tape employing a denatured cobalt magnetic material, the coercive force Hc thereof is dependent upon temperature and if the tape is excessively heated, the anti-magnetic force thereof is lowered and the high frequency characteristic thereof deteriorates. When the magnetic tape is provided with a support base of poly-ethylene terephthalate (PET) excessive heat can cause the tape to shrink longitudinally. Therefore, excessive heat can adversely a~fect a magnetic tape cassette in a number ; 15 of ways which would render the tape cassette substantially useless.
A conventional cassette cannot in~orm the user of the occurrence oE such problems vi~ually directly (or through color change) so that the user can take countermeasures.
Furthermore,- the conventional cassette cannot inform the user of the range of usage temperatures through color change.
~UMMARY OF THE INV~NTION
Accordingly, the object of this invention is to provide a magnetic tape cassette in which the abo~e-described v 25 difficulties are eliminate, so that the magnetic tape can be stably stored and used.
The foregoiny object and other objects of the invention have been achieved by the provision of a magnetic ..
,., ,~ .
1 cassette -tape which includes a temperature indicating member which is bonded to a surface of a cassette half or included in the half ~tself.
BRIEF DESCRIPTION OF THE DRAWINGS
.
Fig. 1 is a plan view of a magnetic tape cassette according to this invention; and Fig. 2 is a sectional view showing essential components of the cassette according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 is a plan view showing one example of a magnetic tape cassette according to one embodiment of the invention, for recording and reproducing audio slgnals.
The cassette has a temperature indicating member 6 which is bonded to a corner of the upper surface 2 of a half 1 : 15 which is relatively flat e~cept for a pair of hub holes 3 and 4 and a window member S.
The temperature indicating member 6, as shown in Fig. 2, comprises a support 7 and a film layer 8 formed on the surface of the support 7 by coating with a coating solution which is prepared by dispersing temperature in dicating pigment in a binder. The temperature indicating member 6 is bonded to the upper surface 2 with an adhesive which is suitably determined from the relation between the materials of the half 1 and the support 7.
The temperature indicating pigment may be of the reversible or non-reversible type, and the grain size rnay preferably be 30 ~ or less, ~l8S36~
1 Examples of suitable reversible temperature indicating pigments are Ag2HgI4, Cu2HyI4, and a solid solution of the mixture of Ag2HgI4 and Cu2HgI4. "Reversible thermopaints" R-4, R-5, R-6, R-7, R-13, R-15 and R-17 manufactured by Rikagaku Kenkyusho are commercially available for use as such reversible temperature indicating pigments.
- 3a -~15~
The properties of the "reversible thermopaints" are as indicated in the following table:
Table 1 color High Low temperature changetemperature - No. color temperature color Remarks R-4Reddish yellow 40C ReddishOrange at about orange 35C
R-5 Yellow 50C Yellowish Reddish yellow orange at about 45C
R-6 Bright 60C Dark brown- Dark red at about yellowish red purple 55C
R-7 Red 70C Dark brown- Dark red at about purple 60C
R-13 Yellow 130C Yellow-orange R-15Lemon-yellow- 150C Yellow green R-17 - Lemon-yellow- 170C Yellow green Examples of suitable non-reversible temperature indicat-ing pigments are [Cu~Pyr)2] ~CNsJ2~ CoI2 2C6H12N4 1OH2O, [Cr~NH3)5Cl]Cz04, NiC12-2C6H12N4rlOH20, 2PbC03~Pb~OH32, CoKP04-H O CdCO NH4VO3, NH4MnP2O7 and Cd~OH)2.
thermopaints #S, ~-7, #8, #9, #11, #13, #14, #16, #18, #20, #22, #25, #27, #29, #31, #33, #36, #41, #44 and #45 manufactured 10- by Rikagaku Kenkyusho are commercially available for use as such non-reversible temperature indicating pigments.
53~8 The properties of the "non-reversible ther~opaints"
are as indicated in Table 2:
i3~;8 Table 2 color Original change No. color temperature Change color Remarks SPale Pink 50C Bright blue 7Pale Pink 70C Pale purple 8. Pale Pink 80C Bright purple 9 Pinlc white 90C Bright purple 11 Pale green 110C Bright bluish Yellowish gray purple at about 70C
13 Purplish 130C Dim bluish pink purple 14 Bluish green 140¢ Pale red-purple 16 Bright 160C Gray-black greenish blue 18 Red-purple 180C Brown-black 20 Pale yellow- 200C Bright bluish orange purple .:
22 White 220C Gray-black Pale pink at about 25 Pale yellow- 250C Bright brown Pale yellow-brown green at about 210C
27 Pale yellow- 270C Pale blue-orange purple 29 Pale pink 290C Black ~ale purple at about 170C
31 Bright blu- 310C Brown black ish gray color Original change No. colortemperature Change color Remarks 33 Pale blue~ 330C Gray-black green 36 White 360C Orange Gray-white at about 290C
41 Blue 410C Brown white 44 White 440C Pale yellow- Bluish white at brown about 210C and bluish black at about 310C
Purple 450C White For the reversible temperature indicating pigments mentioned above, methyl methacrylate-vinyl acetate (1 : 1) - copolymer resin varnish is preferably employed as the binder.
For the non-reversible temperature indicating pigments, ethyl cellulose lacquer is preferably employed as the binder in the case where the color change temperature is 200C or below9 and silicone varnish is preferably employed as the binder in the case where the color change temperature is 200C or higher.
Examples of the above-described support are a plastic sheet of polyethyline terephthalate, cellulose triacetate, vinyl chloride, polycarbonate or the like; paper, synthetic paper, metal foil or the like.
As is apparent from the above description, in the cassette according to the invention, a temperature indicating member 6 whose color is freely changed by the ambient temper-3~
ature is bonded to the upper surface 2 of the half 1, which can be readily seen. Therefore, the deformation of the cassette and deterioration in the magnetic characteristic of the magnetic tape therein due to overheating of the cassette can be detected early. Thus, the cassette can be used at any place and under any operating condition.
It is often impossible to observe the temperature indicating member when the cassette is stored; however, the highest temperature the cassette has been exposed to can be detected later. Similarly, in the case where it is--impossible to observe the temperature indicating member during the use of the cassette, the highest temperature the cassette has under-gone can be detected later by merely observing the color change.
In the case of Fig. 1, only one temperature indicating member 6 is bonded to the surface of the cassette; however, a plurality of temperature indicating members may be bonded to the surface, for example at differing temperature character-istics, or the temperature indicating members may be bonded to both the "A" surface and/or the "B" sur-face of the cassette ~alf.
In the temperature indicating member shown in Fig. 2, the film layer 8 is formed on the support 7; however, the i,nvention is not limited thereto or thereby. That is~ the aforementioned pigment may be mixed with the material which forms the half 1. The same effect can be obtained by directly 53~
coating the surface of the hal-f with the "thermopaint".
The novel effects of the cassette will be clarified by describing a number of concrete examples.
Example 1 , The following materials were kneaded by allowing them to pass through two heated rolls:
Styrol resin (manufactured by Asahi Dau Co.) for fabricating a cassette: 100 parts by wt.
Cu2HgI4 (average particle size 4 ~): 2 parts by wt.
The resultant red mixture was melted by heat, to mold a cassette half, and a complete cassette half was prepared by incorporating a magnetic tape therein. The cassette half was placed on the dash board of a vehicle in the sun, with the windows closed. In forty minutes after the casstte half was placed, it was observed that the color had changed from red into brown-purple. In this case, the surface temperature of the dash board was 67C. Judging from the properties of the tem-perature indicating pigment Cu2HgI4, the color change into brown-purple meant that the surface temperature of the cassette half zo had exceeded 70C.
Example 2 The cassette half was coated with reversible thermo-paint ~7 manufactured by Rikagaku Kenkyusho and held at a S3~
sunny place in a vehicle. In forty minutes, it was observed that the color had changed from pale pink into pale purple.
The temperature in the vehicle was 67C in this experiment.
Concrete Example 3 The reversible thermopaint #7 manu-factured by the Rikagaku Kenkyusho was applied to a PET base 23 ~ in thickness, or the support, to a thickness of lS ~, to prepare the temper-ature indicating member. The temperature indicating member thus prepared was bonded to the cassette half, and the cassette half was held at a sunny place in the vehicle. In forty minutes, it was observed that the color was changed from pale pink into pale purple. In this experiment, the temperature in the vehicle was 67C
Concrete ~xample 4 A non-reversible temperature indicating pigment CoKPO4 H2O and ethyl cellulose lacquer were mixed in the ratio 1 : 1, and the resultant mixture was applied to an ordinary cassette half. After being dried, the cassette was placed in a constant temperature oven in an atmosphere of 150C. In ten minutes, it was observed that the color was changed from rose to blue.
At the same time, the cassette half was taken out of the constant temperature oven, and it was found that the cassette half was deformed. Judging from the properties of the pigment used, the S
color change to blue meant that the cassette half was subjected to a temperature of 140C or higher.
Claims (8)
1. A magnetic tape cassette, comprising; a pair of cassette halves, said halves being joined together and holding a tape therein, wherein at least one said cassette half includes temperature sensitive means adapted to change color at a predetermined temperature so as to give a visual indication of a temperature condition potentially damaging to said cassette or said tape.
2. A cassette as claimed in claim 1, said temperature sensitive material being coated over portions of cassette.
3. A cassette as claimed in claim 1, said temperature sensitive material being formed on a support member, said support being adhered to a cassette half.
4. A cassette as claimed in claim 1, said cassette being made of a plastic, said temperature sensitive material being combined with said plastic upon being molded into said cassette.
5. A cassette as claimed in claim 1, said tem-perature sensitive material being formed of a reversible temperature indicating pigment.
6. A cassette as claimed in claim 5, said pigment being selected from the group consisting of Ag2HgI4,
6. A cassette as claimed in claim 5, said pigment being selected from the group consisting of Ag2HgI4,
Claim 6 continued....
Cu2HgI4, and a solid solution of the mixture of Ag2HgI4 2 g 4
Cu2HgI4, and a solid solution of the mixture of Ag2HgI4 2 g 4
7. A cassette as claimed in claim 1, said temperature sensitive material being formed of a non-reversible temperature indicating pigment.
8. A cassette as claimed in claim 7, said pigment being selected from the group consisting of [Cu(Pyr)2](CNS)2, CoI2.2C6H12N4.10H2O, [Cr(NH3)5ClJC2O4, NiC12.2C6H12N4.10H2O, 2PbCO3.Pb(OH)2, CoKPO4H2O, CdCO3, NH4VO3, NH4MnP2O7, and Cd(OH)2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5273581U JPS57164888U (en) | 1981-04-13 | 1981-04-13 | |
| JP52735/81 | 1981-04-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1185368A true CA1185368A (en) | 1985-04-09 |
Family
ID=12923180
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400854A Expired CA1185368A (en) | 1981-04-13 | 1982-04-13 | Magnetic tape cassette with color change type excess temperature indicator |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS57164888U (en) |
| CA (1) | CA1185368A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2380047A (en) * | 2001-09-21 | 2003-03-26 | Hewlett Packard Co | Data storage cartridge with sensor |
| GB2380046A (en) * | 2001-09-21 | 2003-03-26 | Hewlett Packard Co | Data storage media having integrated environmental sensor |
-
1981
- 1981-04-13 JP JP5273581U patent/JPS57164888U/ja active Pending
-
1982
- 1982-04-13 CA CA000400854A patent/CA1185368A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2380047A (en) * | 2001-09-21 | 2003-03-26 | Hewlett Packard Co | Data storage cartridge with sensor |
| GB2380046A (en) * | 2001-09-21 | 2003-03-26 | Hewlett Packard Co | Data storage media having integrated environmental sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57164888U (en) | 1982-10-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4654260A (en) | Magnetic recording medium | |
| US4555431A (en) | Magnetic recording medium | |
| US5532041A (en) | Magnetic recording media and method for making them | |
| US5089333A (en) | Magnetic recording medium | |
| US4554089A (en) | Ferromagnetic particles with stable magnetic characteristics and method of preparing same | |
| US4396668A (en) | Magnetic recording medium | |
| CA1185368A (en) | Magnetic tape cassette with color change type excess temperature indicator | |
| US4895758A (en) | Magnetic recording medium | |
| EP0152058A1 (en) | Magnetic recording disc and process for the production thereof | |
| US4410590A (en) | Magnetic recording medium | |
| US4780353A (en) | Magnetic recording medium | |
| JPS62222428A (en) | Magnetic recording medium | |
| US4500599A (en) | Magnetic recording medium | |
| US4367263A (en) | Magnetic recording medium | |
| US5326635A (en) | Magnetic recording medium having a non-magnetic underlayer containing electrically conductive tin oxide coated pigment | |
| US5043210A (en) | Magnetic recording media having two magnetic layers; the first for recording a baseboard signal and the second for recording a superimposed surface and signal | |
| CA1065481A (en) | Magnetic recording tape | |
| US3700499A (en) | Magnetic recording element | |
| US4720413A (en) | Magnetic recording medium having a back coat layer | |
| US4748081A (en) | Magnetic recording medium having an improved magnetic layer using particulate alpha-Fe2 O3 and carbon black | |
| US4707403A (en) | Magnetic recording medium having an improved magnetic recording layer | |
| JPH0715750B2 (en) | Magnetic recording medium | |
| JPS55146667A (en) | Cassette tape | |
| US5415928A (en) | Magnetic recording tape | |
| CA1171740A (en) | Magnetic recording medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |