Abstract: The magnetic data eraser includes: a mounting and immobilizing tray on which a magnetic recording medium is mounted, the mounting tray being inclined at an angle of 60±10 degrees to the horizontal; a magnetizer that is encircled by a magnetizing coil, the magnetizer having a hollow portion into which the mounting and immobilizing tray is inserted; and a controller that causes an electric current to flow as an excitation current through the magnetizing coil, the excitation current generating a magnetic field that erases data stored in the magnetic recording medium.

Abstract: A testing configuration for testing a security document includes a security element, having a high-coercivity magnetic material and a low-coercivity magnetic material, a device comprising such a test configuration and to a relevant test method. The high- and low- coercivity magnetic materials of the security element are magnetized in a first direction by the interaction of first and second magnet pair units, and subsequently the low-coercivity magnetic material is remagnetized in a second magnetization direction by means of the second magnet pair unit. The magnet pair units are arranged with respect to one another in such a closely adjacent manner along the transport path of the security document that the first magnet field strength is greater than the magnet field strength provided by the first magnet pair unit alone and is greater than the magnet field strength provided by the second magnet pair unit alone.

Abstract: An electrochemically-gated field-effect transistor includes a source electrode, a drain electrode, a gate electrode, a transistor channel and an electrolyte. The transistor channel is located between the source electrode and the drain electrode. The electrolyte completely covers the transistor channel and has a one-dimensional nanostructure and a solid polymer-based electrolyte that is employed as the electrolyte.

Abstract: Generation of an intense magnetic field to erase high coercivity magnetic media uses delivery of energy to a degaussing cavity. To conserve energy storage and delivery requirements and to obtain a desired magnetic strength generally uniformly within the cavity, strategic placement of supplemental turns at ends of the magnetic field generating coil wound around the cavity can promote uniformity. Construction of at least cavity ends from an adequate quantity of magnetically soft ferrous material can also promote uniformity. A combination of both approaches is possible.

Abstract: A bulk eraser for erasing recorded information on a magnetic-recording disk. The bulk eraser includes a plurality of magnets and a structure magnetically coupled with the plurality of magnets to produce magnetic-flux density in a gap. The gap has a first portion, a second portion and a third portion. Two magnets are disposed with opposing polarity across the first portion of the gap. The plurality of magnets and the structure are configured to produce a magnetic-flux density in the second portion of the gap sufficient to erase recorded information from a portion of at least one magnetic-recording disk in a disk-stack of the hard-disk drive when the hard-disk drive is inserted into the second portion of the gap. The plurality of magnets and the structure are configured to direct the magnetic-flux density in a substantially radial direction of the portion of the magnetic-recording disk.

Abstract: In a portable data erasing device, to prevent data leaks from magnetic disk devices to be disposed, data is erased by a simple operation. The data erasing device using a magnetic field generated by permanent magnets to erase data comprises a sliding tray, a main body and a swinging tray. The sliding tray is movable into and out from the main body, two permanent magnets, adjacently arranged so that the north and south poles thereof have mutually attracting polarities, are attached to the front end of the sliding tray. One end of the swinging tray is fixed to the upper surface of the main body by a shaft, so that a magnetic disk device can be mounted and swung on top of the main body. While the sliding tray is extracted stepwise from the main body, the magnetic disk device can be swung, and data on the magnetic disks erased.

Abstract: A bulk degaussing system for the erasure of magnetic storage media by means of permanent magnets. The bulk degaussing system includes a rotatably mounted carousel and an angular displacement means that angularly displaces the carousel through a predetermined angle after passage of the carousel through a degaussing gap.

Abstract: A manually operated continuous-use desk-top magnetic media eraser/degausser that utilizes elaborately shielded state-of-the-art Rare Earth Magnets to uniformly remove magnetically recorded information from audio and video tapes, PC diskettes, and many other types of magnetic media that can be accommodated by the component's 1.0625 inches high by 4.125 inches wide media transport pathway. The media, as it traverses the pathway, passes through a very strong magnetic field created by two powerful grade N40 (40 MGOe) patented neodymium (NdFeB) permanent magnets placed perpendicular and end-to-end under the center of said pathway. As the recorded media is manually manipulated through the pathway, over the magnets, and out the exit, magnetic information stored on said media is removed by the strong magnetic lines of force present within the protective triple-shielded top, bottom, and side components surrounding the transport pathway.

Abstract: A control apparatus for master/slave outlets having a current sensor, a driver, a large current switch component and a direct-bucking type power supply such that the working power source required by the master/slave equipment can be supplied stably. Further, the control apparatus for master/slave outlets provides a most simplified circuit to perform a function that the slave outlet supplies a power at the time the master outlet is supplied the power.

Abstract: A bulk degaussing apparatus and method for erasing magnetic media of various sizes. A media passage track is provided such that media passing therethrough is uniformly exposed to the magnetic fields provided through the gap. The bulk degaussing apparatus has fixed magnetic pole pairs predisposed for generating uniform magnetic field elements across a gap projecting magnetic flux across the gap for erasing various sizes of magnetic media, with the magnetic media receiving track positioned relative to the poles such that adjacent like poles are arranged on each side of the gap to counteract fringing effects. The bulk degaussing method for erasing various sizes of magnetic media provides a plurality of fixed magnetic pole pairs for generating uniform magnetic field elements on one or more sides of a degaussing region projecting magnetic flux into the region, and arranges the plurality of fixed poles so that adjacent poles counteract fringing effects.

Abstract: A configuration of a thyristor stack is provided. The stack comprises thyristors, electrically conductive bars, and reactors that are mounted around the electrically conductive. Heat sinks may be included in the thyristor stack to assist in heat dissipation, although they may not be necessary. A method for constructing a thyristor stack is also provided.

Abstract: A means for winding orthogonal coil systems that almost completely encompass and closely conform to magnetic media having a circular cylindrical form and orientation, including such media further encased in square or rectangular cassettes, cartridges or disk drives, while providing necessary access to that volume without the use of drawers and separable connectors or flexible lead wires for connection of the coils to energy stored in capacitors. The invention further employs hard wired circuitry for controlling the phase of currents in the coils and maintaining the desired rotation of the magnetic field. While this invention can be realized to degauss media inserted and extracted through the same side of the winding system, it is equally configurable to conveyance of media in one end of an orthogonal coil system and out of the opposing end.

Abstract: A bulk degaussing system automatically adjusts the operating voltage of the system to achieve a predetermined level of magnetic filed strength. A microprocessor is used to monitor the transient response of the system to maintain operation at a predetermined level of stored energy or to detect impending failure.

Abstract: A bulk degaussing system for bulk erasure of various magnetic media includes a source of magnetic flux for generating a magnetic field with a predetermined field strength within a predetermined volume defining a predetermined degaussing window, a transport system for transporting the magnetic media relative to the degaussing window such that every point on the magnetic media is exposed to the magnetic field. A control circuit is included which modulates the magnetic field to reduce power consumption. In addition to reducing power consumption, the modulated magnetic field minimizes system performance degradation due to stalls of the magnetic media transport system due to interactions between the magnetic field and ferromagnetic components associated with certain magnetic media.

Abstract: A device for scrambling the information held by magnetic memory storage media and rendering the information inaccessible. The portable device provides a passage through which a magnetic memory storage medium, also known as a diskette, passes in such proximity to magnetic material so that the magnetically sensitive components of the memory storage medium are thereby disordered by the force of the magnetic field emanating from the magnetic material.

Abstract: The magnetic states of MR reproducing heads are reinitialized during media drive manufacturing by applying initializing magnetic fields to the transducers after they have been manufactured and incorporated into media drive assemblies.

Abstract: To degauss cassettes of magnetic tape, a magnetic field is applied to the magnetic material while the magnetic material moves with respect to the field in a single air gap of a flux density of at least 1,000 gauss and at an angle between 20 degrees and 70 degrees from the horizontal of the magnetic tape for a time priod of at least one second and the field is alternated at a frequency of at least ten hertz. The magnetic material may be rotated while it is in the field.

Abstract: This method produces a tape having a plurality of recorded segments separated by cue tones and having a reduced tendency to generate false cue tones. The method includes applying a layer of a liquid dispersion to a nonmagnetic substrate. The method also includes the steps of orienting the pigment by applying a magnetic field, solidifying the layer of liquid dispersion on the substrate, and applying a demagnetizing field to the layer to neutralize the remanent magnetization.

Abstract: To degauss cassettes of magnetic tape, a magnetic field is applied to the magnetic material with a flux density of at least 1,000 gauss and at an angle between 20 degrees and 70 degrees from the horizontal of the magnetic tape for a time period of at least one second and the field is alternated at a frequency of at least ten hertz. The magnetic material may be rotated while it is in the field.

Abstract: An apparatus for erasing information recorded on a magnetic tape wound into a roll having a diameter. The apparatus comprises an erasing coil wound in the form of a solenoid defining a space therein. The space has a width shorter than the diameter of the magnetic tape roll and a length longer than the diameter of the magnetic tape roll. The magnetic tape roll is moved intermittently to different erasing positions in a predetermined sequence so that the magnetic tape roll has different portions placed in the space at the respective erasing positions. A ringing signal is applied to the erasing coil to provide a magnetic field in the space for erasing information recorded on the magnetic tape roll each time the magnetic tape roll is placed at one of the erasing positions.

Abstract: To degauss cassettes of magnetic tape, a magnetic field is applied to the magnetic material with a flux density of at least 1,000 gauss and at an angle between 20 degrees and 50 degrees from the horizontal of the magnetic tape for a time period of at least one second and the field is alternated at a frequency of at least ten hertz. The magnetic material may be rotated while it is in the field.

Abstract: An erasure system for magnetic information storage media is disclosed by which magnetic media, such as computer, video and audio tapes, cassettes and discs, can be thoroughly erased. The system uses high energy product permanent magnets preferably positioned so that their poles repel one another to induce "bucking magnetic fields" having lines of force active in the three spatial planes and parallel or tangential to the recorded signal track on the media being erased. The DC magnetic field thus applied causes the DC erasure of the media. The AC erasure effect comes about through the relative movement of the media through fixed magnetic fields of opposite polarity, causing the magnetic media to be subjected to a reversing polarity of magnetic saturation. The magnet configurations can be adjusted for use on helically recorded magnetic media, in addition to cross-field and conventional recording techniques.

Abstract: To degausse high coercivity magnetic recording media, a programmable degausser includes at least first and second stations positioned at 45 degrees with respect to an anti-static conveyor belt passing through their centers and at a 90 degree angle with respect to each other. The stations include coils wound on insulated bobbins and the degausser is programmable to selectively operate continuously, operate manually, operate in response to detected recording or operate when there is no low-current or low-temperature warning alarm.

Abstract: A permanent magnet type demagnetizing head has a first magnetic part disposed on a front part(21a.sup.1, 21a.sup.2, 21a.sup.3) of a tape running surface of a magnetic material, a second magnetic part (21c) disposed on a rear part of the tape running surface and a non-magnetic part or a feeble magnetic part (21b) disposed between the first and the second magnetic parts in the tape running direction; and the first magnetic part is magnetized in a magnetic pattern having plural magnetized regions of one or more N-pole and S-pole; the second magnetic part is magnetized in a magnetic pattern of alternating stripes of N-pole regions and S-pole regions, the boundaries between neighboring N-pole regions and S-pole regions are inclined, and the intensity of magnetization are gradually reduced in the tape running direction.

Abstract: A purge erase apparatus is presented to erase information stored on a magnetic disc. A multiplicity of coils are connected in parallel and are arranged around the disc to create a magnetic field having a region of maximum field intensity. When an erase signal is given, the information on the disc will be erased in one or two revolutions of the rotating magnetic disc through the region of maximum field intensity.

Abstract: A unit including a conveyor belt for carrying the tapes to be degaussed, wound on reels, past degaussing coils. The coils are arranged respectively below and above the path of the tapes, spaced along the path of the tapes, and oriented with the magnetic fields positioned at 90.degree. angle to each other and both at 45.degree. angle to the direction of movement of the conveyor. Booster coils are provided for selectively applying lesser and greater voltages to the degaussing coils. Cooling fans direct cooling air against the degaussing coils, and in both of opposite directions on each coil. Safety features include interruption of the operation upon excessive heat of the degaussing coils, too great or too little current to the coils, or too great or too low voltage applied from the main source.

Abstract: A demagnetization apparatus for use with magnetically based electronic article surveillance systems having a dual status anti-theft marker containing at least one demagnetizable control element which when demagnetized allows the marker to be detected by the system when the marker is present in an interrogation zone. The apparatus includes an elongated magnetic section contained within a housing which exhibits a succession of fields of alternate polarity and a portion of which exhibits generally decreasing intensities at the working surface of the housing along that portion of the section. The peak intensity of the outermost field is controlled to have a peak intensity less than that of adjacent regions. The section and a cover plate are oriented such that the external fields near the working surface are sufficient in intensities to demagnetize the demagnetizable element of the marker positioned proximate thereto while being rapidly attenuated a short distance from the section.

Abstract: A bulk degausser for erasing a reel of high energy magnetic tape. The degausser includes a circuit for generating magnetic fields including a coil defining a window for passage of the reel of tape. The coil includes a first winding having relatively few turns and a second winding, inductively coupled to the first winding, having relatively many turns. The circuit also includes an ac power supply connected to the first winding and a dc power supply connected to the second winding. A resonance capacitor is interconnected with the second winding for substantially balancing the inductive reactance of the second winding at the frequency of the ac power supply. The circuit also includes an isolation relay, interconnecting the capacitor and the second winding with the dc power supply, for isolating the dc power supply when the first winding is energized by the ac power supply.

Abstract: An apparatus and method for degaussing a magnetic storage medium, such as a reel of magnetic tape, is disclosed. A pair of opposing E-laminations have windings on their respective center legs. A reel of magnetic tape is inserted in the region between the E-laminations, and is rotated. An AC potential is coupled in series across the windings, to obtain a first magnetic field orientation in the region between the E-laminations. The direction of connection of one of the windings of the series arrangement is then reversed, to electrically alter the magnetic field orientation. This provides an effective degaussing of the magnetic tape.

Abstract: A demagnetization apparatus for use with magnetically based electronic article surveillance systems having a dual status anti-theft marker containing at least one demagnetizable control element which when demagnetized allows the marker to be detected by the system when the marker is present in an interrogation zone. The apparatus includes an elongated magnetic section contained within a housing which exhibits a succession of fields of alternate polarity and a portion of which exhibits generally decreasing intensities at the working surface of the housing along that portion of the section. The section and a cover plate are orientated such that the external fields near the working surface are sufficient in intensities to demagnetize the demagnetizable element of the marker positioned proximate thereto while being rapidly attenuated a short distance from the section.

Abstract: An upper magnet and a lower magnet respectively above and below the objects to be degaussed/demagnetized. They are arranged with their fields mutually transverse, and both at 45.degree. angles to a conveyor carrying the objects between the magnets. Either or both magnets may be rotated, selectively, and they are rotated in opposite directions.

Abstract: The articles to be degaussed are carried along on a conveyor under which is a magnet rotating on an axis extending through the conveyor and the articles.

Abstract: A magnetic material degausser in which the material to be degaussed is placed within the center of a degaussing coil. A capacitive discharge system is employed for energizing the degaussing coil. The capacitor is repeatedly discharged through the coil in such a way that for at least a portion of the degaussing cycle, the energy applied to the coil decreases with each energization. The magnetic material may be rotated within the coil as the degaussing cycle progresses. In one embodiment of the present invention, the energy discharged from the capacitor first increases and then decreases during the degaussing cycle with each energization of the coil. The rotational speed of the magnetic material within the coil may be related to the frequency at which the capacitor is discharged.

Abstract: A method for degaussing a magnetic storage medium, such as a reel of magnetic tape, is disclosed. In the disclosed method, the reel of magnetic tape is simultaneously rotated on its axis and subjected to an applied transverse magnetic field substantially in the plane of the reel. The transverse magnetic field is applied first in one direction and then in the opposite direction. An axial magnetic field, substantially parallel to the axis of the reel, is then applied, first in one direction and then in the opposite direction. In the preferred embodiment, the step of applying an axial magnetic field includes applying axial magnetic fields in alternating directions at successively decreasing amplitudes. In the disclosed apparatus, the transverse magnetic field is obtained using a lateral coil which passes over and under the reel and covers about half the reel. The axial magnetic field is obtained using a ring-shaped coil surrounding the periphery of the reel.

Abstract: A machine having a conveyor for carrying a workpiece to be magnetized therethrough. It includes two demagnetizing magnets arranged at a mutual angle of 90.degree. and both at 45.degree. to the direction of travel on the conveyor. The magnets are arranged respectively above and below the conveyor, and hence above and below the workpiece on the conveyor, and are spaced apart in the direction of travel of the conveyor. The conveyor, structurally, includes a stationary base, and endless belts carrying paddles, the paddles engaging the workpieces and moving them along the base. The workpieces "float, " capable of moving to any position according to the condition of magnetism in them and the position and shape of the demagnetizing magnets, and upon encountering the field of the demagnetizing magnet that is disposed above the workpieces, the workpieces are capable of being attracted up to that demagnetizing magnet, off of the base of the conveyor.

Abstract: A magnetic tape degausser includes a pair of electromagnets which are arranged to project a magnetic field through a magnetic tape reel to magnetically erase the magnetic tape. The magnetic tape degausser includes improvements in the control of the motorized transport mechanism used to control the movement of a tape reel in rotation towards and away from erasing electromagnets. Excitation of the electromagnets is synchronized with the operation of the transport mechanism in a cooperative fashion so that the electromagnets are actuated when the magnetic tape is near the electromagnets and as the magnetic tape is withdrawn from the electromagnets. An alternative version exposes the magnetic tape to a non-uniform field as the tape approaches the electromagnets, and a uniform field as the tape is withdrawn. The speed at which the magnetic tape reel is transported away from the electromagnets is controlled so as to ensure adequate, but noise-free erasure.

Abstract: A degaussing head is mounted on a tape drive transport unit adjacent to a rotating reel of tape. The degaussing head is selectively energized by a signal indicating that the tape is to be erased. Preferably, the degaussing head takes the form of an E-shaped iron core driven by a coil supplied with attenuated DC current. The degaussing head is mounted on the door of the tape drive transport cabinet in such a manner that when the door is closed the legs of the degaussing head orthogonally span the tape in the reel to provide an attenuated alternating magnetic field for bulk erasing the tape as it is rotated past the head.

Abstract: Apparatus is disclosed for bulk erasing magnetic tapes spirally wound on a carrier. A pair of magnetic structures are spaced apart by an air gap of sufficient width to receive the tape carrier. Circuitry is provided for producing a rotating magnetic field in the air gap substantially parallel with the tape. Preferably, the magnetic structures take the form of multi-legged iron cores. The cores are mounted so that corresponding legs on opposing cores have the same magnetic polarity. A phase shifter circuit is adapted to supply currents 90.degree. out of phase with one another to selected pairs of legs in the cores to create a rotating magnetic field in the air gap.

Abstract: A demagnetizing device for a cassette tape player includes a cassette shell which defines a generally oval-shaped guide track extending around the interior of the shell. A magnet assembly is provided with shafts which fit within the guide track such that the magnet assembly is free to rotate within the guide track and to translate along the length of the guide track. The magnet assembly is rotated by a drive belt which in turn is driven by two hubs rotatably mounted in the cassette shell. An automatic shutoff lever is disclosed which acts automatically to shutoff a tape player equipped with automatic shutoff features when the magnet assembly reaches one of two predetermined positions on the guide track. By properly positioning the guide track, the single magnet assembly can be used to demagnetize multiple components of a tape player distributed around the cassette shell. For example, the single magnet assembly can be used to demagnetize two capstans and a tape head in a single operation.

Abstract: A magnetic tape de-gausser includes a pair of electromagnets which are arranged to project a magnetic field through a magnetic tape reel to magnetically erase the magnetic tape. The electromagnets are mounted to be movable so as to tightly accomodate various size tape reels between the electromagnets. Structures are provided to control the separation between the electromagnets, to prevent a tape reel from destructively contacting an electromagnet, and to control the movement of a tape reel in rotation towards and away from electromagnets.

Abstract: A mass degaussing apparatus is disclosed which comprises a movable dolly capable of holding a plurality of magnetic tapes. Automatic means are provided for moving the dolly into and out of a degaussing chamber wherein means are provided to generate an electromagnetic field. The apparatus is capable of degaussing a large plurality of magnetic tapes in a single operation.

Abstract: A compact hand-held demagnetizing device is used for demagnetizing a magnetic recording and reproducing head. It comprises a handle portion and a demagnetizing head. The handle portion contains a circuit for generating a decreasing alternating current for exciting a drive coil for the demagnetizing head. Means is provided to indicate the time when the demagnetizing operation is initiated or when the demagnetizing operation can be initiated and when the demagnetizing operation is completed.

Abstract: An erase head for erasing single tracks on multi-track magnetic recording tapes by means of a constant magnetic field applied in a direction perpendicular to the direction of tape travel, to avoid any asymmetrical residual magnetization with respect to the direction of a magnetizing field used for recording. A configuration of two pole pieces and two corresponding shields, spaced out from the pole pieces and generally coplanar with the end faces thereof, ensures that the magnetic field strength is relatively uniform in a region between the shields, and falls to a relatively low value outside this region.

Abstract: A combined eraser and splice finder for an NAB tape cartridge which comprises apparatus for subjecting an NAB tape cartridge to an initially strong and thereafter diminishing and vanishing oscillating magnetic field for bulk tape erasure and which, independently or at the termination of the erasure cycle, also senses the presence of the tape splice and stops tape travel within the cartridge at a point where subsequent recording can begin immediately behind the splice. The apparatus is capable of erasure without splice-finding or splice-finding without erasure.

Abstract: In a bulk tape eraser, the outer edge of one outer limb of an E shaped electromagnet on which the energizing coil is mounted is chamfered inwardly to form said outer limb with a narrow free end adjacent its inner edge which directs substantially the whole of the magnetic flux to the central limb of the magnet.

Abstract: A degausser has a housing having two housing sections of generally tubular configurations. A support element is accommodated in the interior of the housing, and has a tubular portion and a generally flat portion. A core of an electromagnet is accommodated in the tubular portion of the support element, and a coil of the electromagnet surrounds a part of the tubular portion in the housing. The flat portion is formed with resiliently yieldable projections which engage associated recesses at the housing sections with snap action so as to connect the housing sections to the support element. Electric leads pass through an opening of one of the sections, are received in slots of the flat portion in a labyrinthine manner, and connected to a switch supported on the support element and having an actuating element passing through a slot in the housing to the exterior of the latter. The housing and the support element are of synthetic plastic material.