JP2013171605A - Magnetically recorded data destruction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetically recorded data destruction device which offers improved energy efficiency and work efficiency in destroying data on a recording medium.SOLUTION: A magnetically recorded data destruction device 100 includes; a capacitor 30; a magnetic field generating coil 40 which accommodates a recording medium and destroys magnetically recorded data thereon by a magnetic field generated by the coil; a switching element SW2 which is turned on and off by a control signal and allows electrical energy accumulated in the capacitor 30 to flow through the magnetic field generating coil 40 as a current when turned on; a current detector 80 for detecting the current flowing through the magnetic field generating coil 40; and a controller 50 which generates the signal for turning off the switching element SW2 when the current detected by the current detector 80 reaches a threshold or more.

Description

  The present invention relates to a magnetic recording data destruction device that destroys magnetic recording data recorded on a recording medium such as a magnetic tape or a hard disk device in an unrecoverable manner.

  For example, when a recording medium such as a magnetic tape used in a general-purpose computer is discarded, the magnetic recording data recorded on the recording medium is destroyed irreversibly to prevent others from reading the recording data. Security measures are taken such as.

  Software that makes magnetic recording data unrecoverable exists, but such software overwrites random data or “00” data on the magnetic tape to prevent restoration. Takes a lot of time.

Therefore, a data erasing apparatus has been developed that erases magnetic data in a short time without overwriting data using the software as described above. For example, Japanese Patent Application Laid-Open No. 2007-213701 discloses a technique for demagnetizing a magnetic tape using an alternating attenuation magnetic field generated in an air-core coil connected in series to a DC power source using a capacitor.
JP 2007-213701 A

  An outline of a conventional magnetic recording data destruction apparatus will be described. FIG. 10 shows an outline of a conventional magnetic recording data destruction apparatus. In FIG. 10, the capacitor C is charged by a charging circuit (not shown). When the charging is completed, a control signal is input to the switching element SW such as a thyristor, and the capacitor C is turned on by closing the circuit. A current flows through the magnetic field generating coil, and a magnetic field is generated in the magnetic field generating coil.

  In this magnetic field generating coil, a magnetic tape or the like intended to destroy the magnetic recording data is accommodated in advance, and the magnetic tape is forcibly magnetized in one direction by the magnetic field generated by the magnetic field generating coil. The magnetic recording data in the magnetic tape is destroyed.

  FIG. 11 is a diagram illustrating a cycle of charging and discharging the capacitor C when destroying magnetic recording data of a plurality of recording media. 11A shows the voltage V of the capacitor C, and FIG. 11B shows an outline of the current I flowing through the magnetic field generating coil.

During the time T ₁ during which the capacitor C is charged, the recording medium to be destroyed in the magnetic recording data is set in the magnetic field generating coil, and then the switching element SW is turned on for Td time to discharge the capacitor C. A magnetic field is generated in the magnetic field generating coil to destroy the magnetic recording data. As shown in FIG. 11, by repeating this, the magnetic recording data of a plurality of recording media are destroyed.

By the way, there are a plurality of types of recording media, and depending on the recording media, the magnetic field strength lower than the magnetic field strength generated by inputting all of the electric energy stored in the capacitor C into the magnetic field generating coil is sufficient in the recording medium. Some magnetic recording data can be destroyed. However, in the magnetic recording data destruction apparatus according to the conventional technique, since all the electric energy stored in the capacitor C is used, there is a problem that the energy efficiency is poor. Conventionally, since all the electric energy stored in the capacitor C is used, it takes time to recharge the capacitor C, and it takes time until the magnetic recording data of the next recording medium is destroyed. As a result, there was a problem that the efficiency of data destruction work deteriorated.

  In order to solve the above problem, an invention according to claim 1 is directed to a capacitor, a magnetic field generating coil that destroys magnetic recording data recorded on the recording medium by a magnetic field that is generated by containing the recording medium, and a control signal. A switching element that switches on or off and causes the electric energy stored in the capacitor to flow to the magnetic field generating coil as a current when turned on, and a current detection unit that detects the current flowing to the magnetic field generating coil And a control unit that generates a control signal for turning off the switching element when a current value detected by the current detection unit exceeds a threshold value. .

  The invention according to claim 2 is turned on or off based on a capacitor, a magnetic field generating coil for destroying magnetic recording data recorded on the recording medium by a magnetic field generated by accommodating the recording medium, and a control signal. And a switching element that causes the electric energy stored in the capacitor to flow through the magnetic field generating coil as a current, a magnetic field detection unit that detects a magnetic field intensity generated in the magnetic field generating coil, and the magnetic field detection And a control unit that generates a control signal for turning off the switching element when the magnetic field intensity detected by the unit exceeds a threshold value.

  The invention according to claim 3 is turned on or off based on a capacitor, a magnetic field generating coil that destroys magnetic recording data recorded on the recording medium by a magnetic field generated and contained in the recording medium, and a control signal. And switching element that turns on the electric energy stored in the capacitor as a current to flow through the magnetic field generating coil, the voltage detection unit that detects the voltage of the capacitor, and the voltage detection unit A magnetic recording data destruction apparatus, comprising: a control unit that generates a control signal for turning off the switching element when the voltage is equal to or lower than a threshold value.

  According to a fourth aspect of the present invention, there is provided the magnetic recording data destruction apparatus according to any one of the first to third aspects, wherein the threshold value is stored.

  The invention according to claim 5 is the magnetic recording data destruction apparatus according to any one of claims 1 to 4, wherein the switching element is a transistor.

  The invention according to claim 6 is the magnetic recording data destruction apparatus according to claim 5, wherein the transistor is one of MOS, JFET, and SIT.

  In the magnetic recording data destruction apparatus according to the present invention, depending on the type of the recording medium, the switching element that flows the electric energy stored in the capacitor as a current to the magnetic field generating coil based on the detection information such as the current is turned off. Makes it possible to destroy the data on the recording medium without using up the electrical energy stored in the capacitor, thus improving energy efficiency and saving the time required for recharging. The efficiency of data destruction work is improved.

1 is a diagram showing an outline of a magnetic recording data destruction apparatus 100 according to a first embodiment of the present invention. It is a figure which shows the memory | storage data example in the reference table 60 of the magnetic recording data destruction apparatus 100 which concerns on 1st Embodiment of this invention. It is a figure which shows the mode of the data destruction of the recording medium in the magnetic recording data destruction apparatus 100 which concerns on 1st Embodiment of this invention. It is a figure which shows the control flowchart at the time of performing the data destruction of a several recording medium continuously. It is a figure which shows the charge and discharge cycle of the capacitor | condenser 30. FIG. It is a figure which shows the outline | summary of the magnetic recording data destruction apparatus 100 which concerns on 2nd Embodiment of this invention. It is a figure which shows the memory | storage data example in the reference table 60 of the magnetic recording data destruction apparatus 100 which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline | summary of the magnetic recording data destruction apparatus 100 which concerns on 3rd Embodiment of this invention. It is a figure which shows the example of the memory | storage data in the reference table 60 of the magnetic recording data destruction apparatus 100 concerning 3rd Embodiment of this invention. It is a figure which shows the outline | summary of the magnetic recording data destruction apparatus based on the prior art. It is a figure which shows the cycle of charge and discharge of the capacitor | condenser C. FIG.

  Hereinafter, the embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of a magnetic recording data destruction apparatus 100 according to the first embodiment of the present invention.

  In FIG. 1, the voltage of the commercial power source is boosted by a booster 10 such as a transformer, and is further converted to a direct current by a rectifier 20 made of a diode. The current output from the rectifier 20 charges the capacitor 30 when the switching element SW1 is on.

  The magnetic field generating coil 40 destroys the magnetic recording data recorded on the recording medium by a magnetic field generated by accommodating the recording medium. In order to generate the magnetic field generating coil 40, the switching element SW2 is turned on so that the electric energy charged in the capacitor 30 flows through the magnetic field generating coil 40. The current detector 80 detects the magnitude of the current flowing into the magnetic field generating coil 40.

  In the present invention, as the switching element SW2 for performing on / off control, any of transistors such as MOS (Metal Oxide Semiconductor), JFET (Junction Field Effect Transistor) or SIT (Static Induction Transistor) is used. preferable.

  The control unit 50 obtains information from a configuration connected thereto such as the input unit 70 and the current detection unit 80, and issues a control signal for controlling on / off of the switching element SW1 and the switching element SW2. Although such a control unit 50 can be configured by an analog circuit, a case where a microcomputer or the like is used as the control unit 50 will be described below as an example.

  The input unit 70 functions as an interface unit that can input predetermined setting information and the like to the control unit 50. The reference table 60 stores data referred to by a program that operates in the control unit 50. FIG. 2 is a diagram showing an example of stored data in the reference table 60 of the magnetic recording data destruction apparatus 100 according to the first embodiment of the present invention.

The required magnetic field varies depending on the type of recording medium on which the magnetic recording data is to be destroyed by the magnetic recording data destruction apparatus 100. Therefore, the reference table 60 includes, for example, “data destruction target recording medium type” which is the type of the recording medium, “generated magnetic field H” necessary for destroying data recorded on the recording medium, It is a current value necessary for generating the generated magnetic field, “threshold current I” which is a reference value for turning off the switching element SW2, and necessary for recharging the capacitor 30 after the necessary magnetic field is generated. The “recharge time T2” is converted into data.

In the present embodiment, as “data destruction target recording medium type”, “open reel type magnetic tape (holding force C ₁ )”, “old cassette type magnetic tape (holding force C ₂ )”, “new cassette type magnetic tape (holding force) C ₃ ) ”,“ Hard Disk (holding force C ₄ ) ”and corresponding data are listed as examples, but the present invention is not limited to such examples. In the present embodiment, it is assumed that the holding force increases and the required magnetic field increases as the type of the recording medium that is subject to data destruction becomes the latter. As a result, the value of the current I serving as a threshold increases as the type of recording medium becomes the latter, and the time T ₂ required for recharging also increases.

In the magnetic recording data destruction apparatus 100 configured as described above, for example, the destruction of the magnetic recording data of the “open reel type magnetic tape (holding force C ₁ )” from the input unit 70 is set. Then, the control unit 50 refers to the data corresponding to the “open reel type magnetic tape (holding force C ₁ )” in the reference table 60 and switches the switching element SW.
1 and a control signal for controlling on / off of the switching element SW2.

  FIG. 3 shows a case in which a recording medium intended to destroy magnetic recording data is set in the magnetic field generating coil 40, the switching element SW2 is turned on, and a magnetic field is generated in the magnetic field generating coil 40 to destroy the data on the recording medium. It shows the state.

  Next, the control of the control unit 50 when data destruction of a plurality of recording media is continuously performed by the magnetic recording data destruction apparatus 100 of the present invention configured as described above will be described. FIG. 4 is a diagram showing a control flowchart when data destruction of a plurality of recording media is performed continuously, and FIG. FIG.

  5A shows the voltage V of the capacitor 30, and FIG. 5B shows an outline of the current I flowing through the magnetic field generating coil 40. In FIG. 4, when the control is started in step S100, in step S101, the control unit 50 transmits a control signal for turning on the switching element SW1, and starts charging the capacitor 30.

In step S102, it is determined whether or not the current cycle is the first cycle of data destruction on the recording medium. If the judgment is YES at step S102, the process proceeds to step S103, it is determined whether or not a predetermined time T ₁ elapses, if the determination becomes YES, and the process proceeds to step S104, the capacitor 30 a switching element SW1 as an off Stop charging. This time T ₁ is the time required for the capacitor 30 to be fully charged from the state where the electric charge charged in the capacitor 30 is zero.

If the judgment is NO at step S102, the process proceeds to step S109, it is determined whether or not a predetermined time T ₂ has elapsed, if the determination becomes YES, and the process proceeds to step S104, the capacitor 30 a switching element SW1 as an off Stop charging. This time T ₂ is the time required for the capacitor 30 to be recharged after a current is passed through the magnetic field generating coil 40. Naturally, T ₂ <T ₁ , so that the charging time of the capacitor 30 for the second and subsequent times can be restricted. As a result, the efficiency of data destruction work can be improved.

  In the process of charging the capacitor 30 as described above, it is assumed that a recording medium for destroying data is set in the magnetic field generating coil 40.

  Subsequently, in order to put the electric energy of the capacitor 30 charged as described above into the magnetic field generating coil 40, the switching element SW2 is turned on in step S105.

  In step S106, it is determined whether the current value detected by the current detection unit 80 is equal to or greater than a threshold value. If the determination in step S106 is YES, the process proceeds to step S107, where a control signal for turning off the switching element SW2 is issued, and the electrical energy stored in the capacitor 30 is saved. As described above, in the present embodiment, when the current value exceeds the threshold value, the switching element SW2 is turned off to generate the minimum necessary magnetic field according to the recording medium that performs data destruction. Efficiency is improved.

  In step S108, it is determined whether a series of data destruction work has been completed. If the determination is NO, the process returns to step S101 to recharge the capacitor 30, and if the determination is YES, the process proceeds to step S110 to end the control.

  As described above, in the magnetic recording data destruction apparatus 100 according to the present invention, the switching element SW2 that causes the electric energy stored in the capacitor 30 to flow to the magnetic field generating coil 40 as a current based on the current detection unit 80 such as a current is provided. By turning off, depending on the type of the recording medium, it becomes possible to destroy the data of the recording medium without using up the electric energy stored in the capacitor 30, so that energy efficiency is improved and recharging is performed. Time required can also be saved, and the efficiency of data destruction work on the recording medium is improved.

  Next, a second embodiment of the present invention will be described. In the first embodiment, the timing at which the switching element SW2 is turned off is determined based on the current detection information by the current detection unit 80. However, in this embodiment, the detection information of the magnetic field detection unit 81 is used instead. The timing for turning off the switching element SW2 is determined based on the above.

  FIG. 6 is a diagram showing an outline of a magnetic recording data destruction apparatus 100 according to the second embodiment of the present invention. In the present embodiment, a magnetic field detection unit 81 is disposed in the magnetic field generation coil 40, the magnetic field intensity generated in the magnetic field generation coil 40 is detected by the magnetic field detection unit 81, and the detected magnetic field strength is input to the control unit 50. It has become.

  In the present embodiment, as the magnetic field detection unit 81 is provided as a detection means for obtaining a threshold value, the reference table 60 is as shown in FIG. FIG. 7 is a diagram showing an example of stored data in the reference table 60 of the magnetic recording data destruction apparatus 100 according to the second embodiment of the present invention.

  The reference table 60 according to the second embodiment includes, for example, a “data destruction target recording medium type” that is a type of recording medium, and a “generated magnetic field H” that is necessary for destroying data recorded on the recording medium. The “recharge time T2” required for recharging the capacitor 30 after generating the necessary magnetic field is converted into data. In this embodiment, since the required magnetic field is directly measured by the magnetic field detector 81, there is an advantage that the accuracy is higher than in the first embodiment in which the magnetic field strength is indirectly estimated from the current value.

Also in this embodiment, the magnetic field required to destroy the data on the recording medium is increased, and the time T ₂ required for recharging is also increased.

  The magnetic recording data destruction apparatus 100 according to the second embodiment of the present invention having the above-described configuration is basically the first embodiment except that the magnetic field strength detected by the magnetic field detection unit 81 is used as the threshold value. The control unit 50 can be operated according to the control flowchart described in the above.

  The magnetic recording data destruction apparatus 100 according to the second embodiment of the present invention as described above can also enjoy the same effect as the previous embodiment.

  Next, a third embodiment of the present invention will be described. In the first embodiment, the timing at which the switching element SW2 is turned off is determined based on the current detection information by the current detection unit 80. However, in this embodiment, instead of this, the detection information of the voltage detection unit 82 is detected. The timing for turning off the switching element SW2 is determined based on the above.

  FIG. 8 is a diagram showing an outline of a magnetic recording data destruction apparatus 100 according to the third embodiment of the present invention. In the present embodiment, a voltage detector 82 is provided in parallel with the capacitor 30, and the capacitor 30 detects the voltage of the capacitor 30 and inputs the detected voltage to the controller 50.

  In the present embodiment, the reference table 60 is as shown in FIG. 9 as the voltage detector 82 is provided as a detecting means for obtaining a threshold value. FIG. 9 is a diagram showing an example of stored data in the reference table 60 of the magnetic recording data destruction apparatus 100 according to the third embodiment of the present invention.

  The reference table 60 according to the third embodiment includes, for example, a “data destruction target recording medium type” that is the type of the recording medium, and a “generated magnetic field H” that is necessary to destroy the data recorded on the recording medium. Further, the “voltage V” of the capacitor 30 after generating the generated magnetic field and the “recharge time T2” required for recharging the capacitor 30 after generating the necessary magnetic field are converted into data. .

  In the third embodiment, when the magnetic field required for destroying the data on the recording medium increases, the power required increases, so the voltage V of the capacitor 30 decreases. Therefore, in the present embodiment, when the voltage V becomes equal to or lower than the threshold value, the switching element SW2 is controlled to be turned off.

  The magnetic recording data destruction apparatus 100 according to the third embodiment of the present invention having the above-described configuration is basically the same except that the voltage detected by the voltage detection unit 82 is used as a threshold value as described above. The control unit 50 can be operated according to the control flowchart described in the first embodiment.

  The magnetic recording data destruction apparatus 100 according to the third embodiment of the present invention as described above can also enjoy the same effect as the previous embodiment.

  In the above embodiment, the open reel type magnetic tape has been described as an example of the recording medium. However, the magnetic recording medium that can destroy data by the magnetic recording data destruction apparatus 100 according to the present invention is not limited to this. It also includes hard disks and flexible disks.

DESCRIPTION OF SYMBOLS 10 ... Boosting part 20 ... Rectification part 30 ... Capacitor 40 ... Magnetic field generating coil 50 ... Control part 60 ... Reference table 70 ... Input part 80 ... Current detection part 81 ... Magnetic field detector 82 ... Voltage detector 100 ... Magnetic recording data destruction devices SW, SW1, SW2 ... Switching element D ... Diode

Claims (6)

A capacitor,
A magnetic field generating coil for destroying magnetic recording data recorded on the recording medium by a magnetic field generated by containing the recording medium;
Based on the control signal, it is turned on or off, and when turned on, a switching element that flows the electric energy stored in the capacitor as a current to the magnetic field generating coil,
A current detector for detecting a current flowing in the magnetic field generating coil;
A magnetic recording data destruction apparatus, comprising: a control unit that generates a control signal for turning off the switching element when a current value detected by the current detection unit is equal to or greater than a threshold value. A capacitor,
A magnetic field generating coil for destroying magnetic recording data recorded on the recording medium by a magnetic field generated by containing the recording medium;
Based on the control signal, it is turned on or off, and when turned on, a switching element that flows the electric energy stored in the capacitor as a current to the magnetic field generating coil,
A magnetic field detector for detecting a magnetic field intensity generated in the magnetic field generating coil;
A magnetic recording data destruction apparatus comprising: a control unit that generates a control signal for turning off the switching element when a magnetic field intensity detected by the magnetic field detection unit exceeds a threshold value. A capacitor,
A magnetic field generating coil for destroying magnetic recording data recorded on the recording medium by a magnetic field generated by containing the recording medium;
Based on the control signal, it is turned on or off, and when turned on, a switching element that flows the electric energy stored in the capacitor as a current to the magnetic field generating coil,
A voltage detector for detecting the voltage of the capacitor;
And a controller for generating a control signal for turning off the switching element when the voltage detected by the voltage detector is equal to or lower than a threshold. The magnetic recording data destruction apparatus according to any one of claims 1 to 3, further comprising a table for storing the threshold value. 5. The magnetic recording data destruction apparatus according to claim 1, wherein the switching element is a transistor. 6. The magnetic recording data destruction apparatus according to claim 5, wherein the transistor is one of MOS, JFET, and SIT.

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