Wang Laboratories, Inc.

Houshang Rasekhi

Alfred M Nelson

John J Sudano

Frederick A Rupinski

George G Pick

John S Kula

Ronald J Cieplik

James P Johnston

Walter B Hatfield, Jr

There is provided improvements in magnetic recording head arrangements, such as may employ multiplexing, which provide substantially higher speeds of recording and require fewer components. The recording head is comprised of a compact, four-layer laminate structure mountable on a supporting substrate, in which the entire array of recording elements forms a flexible, uniquely arranged first layer, the return paths of the recording elements comprise a flexible second layer which has the dual utility of substantially reducing the recording element circuit inductance, the third layer is a rigid printed circuit board structure providing a mount for the blocking diodes and the conductive paths of the associated multiplexing scheme, and the fourth layer is a ground plane located between the first and third layers and insulated therefrom for further reducing the inductance associated to the circuitry of the first layer and for substantially minimizing the circuit inductance of the third layer.

Magnetic recording heads

A recording head protective overlay arrangement with an alarm capability is provided. The protective overlay is continuously replenishable between the recording surface of the recording head and the recording medium and is movable in a direction opposite to that of the recording medium so as to provide a cleaning function as well as a wear-preventive function. A dispenser cartridge housing the protective overlay is provided which is specially designed to closely conform to the recording head. A pivotable cartridge holder is included for enabling the cartridge to be inserted in a position remote from the recording head and pivotable into an operative position with the recording head. The tape medium itself and various components operatively associated therewith are pivotably mounted, to provide movement of the medium into intimate operative contact with the overlay and the recording head.

Recording head protective overlay and cleaning arrangement

A magnetographic copier system in which images recorded on a magnetic tape are developed by toner with magnetic properties and where the toner particles are also electrostatically charged. A piece of paper is brought into contact with the tape at a toner transfer station and a first momentary electric field of the proper polarity and orientation is then used to transfer the developed toner images from the tape to paper. The paper and tape segments with the images are then separated and are moved away from the toner transfer station. An electrode external to the transfer station is then used to apply another electric field of the same polarity to the developed toner images on the paper to prevent the toner from being disturbed by the next occurrence of the first electric field for subsequent toner images being transferred to the paper.

Apparatus for preventing removal of toner from transferred images

Improved recording head structures having lower recording current requirements and planar construction which are mass-producible with high reliability. Associated with the conductors constituting the recording elements are one or more selected materials, predeterminably situated, for substantially reducing the reluctance of the magnetic writing circuit associated to the conductor recording zone. The material is arranged to at least partially define the recording zones and to shield the recording medium from the magnetic fields associated to the recording elements outside of the recording zones. Through appropriate choice and placement of such material, a pre-biasing effect may be achieved thus enabling further reduction in recording currents.

Magnetographic recording heads

Apparatus is provided for uniformly premagnetizing magnetic media, such as wide magnetic tapes and/or for substantially uniformly orienting the magnetic particles in the slurry of the magnetizable layer of magnetic media during their formation. Premagnetization constitutes magnetizing the medium in a preselected direction, such as the transverse direction (i.e., perpendicular to the intended direction of movement of the recording medium past a recording head but in the plane of the medium), prior to magnetically recording information thereon. The apparatus comprises a number of predeterminably arranged small magnets disposed proximate to the medium which obviates the need for large, expensive, heavy magnets and magnet systems. A continuous transverse saturation level of magnetization is provided in the medium with virtually no vertical or longitudinal magnetic components or anomalous effects. A preferred arrangement comprises a number of wafer magnets each having an elongated edge of a pole face disposed proximate to the medium and at a preselected acute angle relative to the direction of intended movement of the magnetic medium.

Magnetizing apparatus

Magnetographic printing, method and apparatus are used to generate letter-quality, relatively high speed transfer of magnetic toner particles from a magnetic tape to paper. A pretransfer force (f.sub.1) holding the toner to the tape is established which may be magnetic, or both magnetic and electrostatic in nature. The transfer operation employs relatively high speed approaching movement of the tape toward the paper in a controlled manner such that forces (f.sub.2) exerted on the toner particles due to the rapidly closing movement including forces created by air currents are collectively less than the toner-holding force (f.sub.1) for any instantaneous separation between the tape and paper. The operation may include the use of a bias voltage to generate a component of the electrostatic holding force and the use of a corotron to deposit electrostatic charge on the magnetic toner particles. The controlled movement of the tape toward the paper is achieved with a cam in one embodiment and with a solonoid in another embodiment.

Magnetic toner transfer method and apparatus

An apparatus and method are disclosed for electrostatically separating a first medium such as a magnetic tape from a second medium such as paper following transfer of images from the tape to the paper. The apparatus includes a movable member or platen disposed for moving the tape into contact with and away from the paper, and a voltage source coupled across predetermined portions of the tape and platen. The method includes the step of creating an electrostatic force between the tape and platen sufficient to overcome adherence of the tape to the paper during contact of the tape with the paper, facilitating separation of the tape from the paper as the platen is moved away from the paper following image transfer. Separation is accomplished substantially independent of tape tension. This permits operation with significantly less tape tension which, in turn, preserves tape integrity and provides for reduced tape breakage and misregistration of tape with paper, more effective cleaning of the tape, and less wear of the tape and the tape cleaning devices.

Apparatus and method for separating adhering media electrostatically

A method of fabricating from a single piece of copper foil the extremely fragile recording element structure of a multi-channel magnetic recording head having a linear array of bi-metal recording elements, in which the elements are comprised of elongated substantially parallel finger portions terminating in a common return, with each having a minutely thinned down recording zone. For high resolution recording head structures, the dimensions of the elements at the recording zone may typically be as thin as 0.1.times.10.sup.-3 inches with a width of 1.5.times.10.sup.-3 inches and length of 3.5.times.10.sup.-3 inches, where the total length of the recording elements may nevertheless be as long as three inches. The process comprises an etching technique and the application of one or more supports at appropriate times in the fabrication to protect the structure at its most vulnerable times. Full masking and deposition of bi-metal layer areas is accomplished prior to any etching steps to avoid, for example, having to re-register the recording element design on one side of the copper foil relative to the other.

Process for fabricating recording heads for magnetography

In a high-quality, high-speed magnetographic apparatus, an arrangement for developing the latent magnetic images of a readily-imagable magnetizable medium (in particular a relatively high-coercivity medium) with magnetically attractable toner particles. A rotatable toner developer is positioned proximate to the medium to define therebetween a toning zone, with the developer being structured to magnetically provide toner particles in contact with the medium at the toning zone and to impart to the toner particles at least at and approaching the toning zone a direction of movement relative to the medium which is in opposition to the latter. A concentration of substantially fluidized and magnetically confined toner particles is thus provided which is urged into contact with the medium for effectively developing the latent images even with the medium moving at high speed relative to the developer and without adversely affecting the latent magnetic images of the medium. A magnetic field enhancer is positioned proximate to the toning zone on the opposite side of the magnetic medium from the developer, which effectively enhances the shape of the magnetic field at the toning zone in the general direction toward the magnetic medium thereby increasing the magnetically generated toner contact pressure. A scavenger arrangement is included for collecting any air-borne toner, for removing excess toner residing on the developed image areas of the medium, and for removing stray toner particles residing on the non-imaged areas and the back of the medium. The continuity of toning provided to the medium is facilitated by an eccentrically operated toner rake arrangement situated in the toner bin for urging the toner particles in the toner bin toward the developer. Alternatively, the toner can be rendered fluidized by a oscillating floor or wall arrangement resiliently coupled to the remainder of the toner bin. The developer is provided with a channel arrangement governing the approach of the toner particles thereto which are received from the action of say the toner rake. The channel arrangement ensures that the toner is introduced to the developer in a well defined narrow band the width dimension of which is commensurate with the width of the desired imaged portion of the magnetic medium. The developer station is particularly effective in both a substantially horizontal orientation, underneath the magnetic medium, and at a substantially vertical angle and proximate to the outside surface of the medium.

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Convent Station, NJ, United States of America

Houshang Rasekhi