WO1985000918A1 - Procede et dispositif d'enregistrement magnetique hydrodynamique - Google Patents

Procede et dispositif d'enregistrement magnetique hydrodynamique Download PDF

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Publication number
WO1985000918A1
WO1985000918A1 PCT/US1984/001224 US8401224W WO8500918A1 WO 1985000918 A1 WO1985000918 A1 WO 1985000918A1 US 8401224 W US8401224 W US 8401224W WO 8500918 A1 WO8500918 A1 WO 8500918A1
Authority
WO
WIPO (PCT)
Prior art keywords
recording medium
transducer
liquid
recording
arrangement according
Prior art date
Application number
PCT/US1984/001224
Other languages
English (en)
Inventor
Andrew M. Bardos
Jon E. Holmes
Original Assignee
Harris Graphics Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Harris Graphics Corporation filed Critical Harris Graphics Corporation
Priority to GB08506178A priority Critical patent/GB2153302B/en
Publication of WO1985000918A1 publication Critical patent/WO1985000918A1/fr

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
    • G11B23/50—Reconditioning of record carriers; Cleaning of record carriers ; Carrying-off electrostatic charges
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G19/00—Processes using magnetic patterns; Apparatus therefor, i.e. magnetography
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B21/00—Head arrangements not specific to the method of recording or reproducing
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B21/00—Head arrangements not specific to the method of recording or reproducing
    • G11B21/16—Supporting the heads; Supporting the sockets for plug-in heads
    • G11B21/20—Supporting the heads; Supporting the sockets for plug-in heads while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier
    • G11B21/21—Supporting the heads; Supporting the sockets for plug-in heads while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier with provision for maintaining desired spacing of head from record carrier, e.g. fluid-dynamic spacing, slider
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/41—Cleaning of heads
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/60—Fluid-dynamic spacing of heads from record-carriers

Definitions

  • the present invention relates in general to magnetic imaging on a recording medium, such as a drum or disk, and particularly to a technique for improving the coupling between a magnetic recording head and the surface of the recording medium.
  • the information recording mechanism of a magnetographic recording apparatus may take on various configurations, such as one using an optical exposure station for selectively erasing (demagnetizing) a premagnetized recording medium (e.g. chromium oxide) , or a configuration employing a magnetic write head through which a latent image of the information to be recorded is directly magnetically written onto the recording medium.
  • a premagnetized recording medium e.g. chromium oxide
  • a configuration employing a magnetic write head through which a latent image of the information to be recorded is directly magnetically written onto the recording medium.
  • the surface of the recording medium usually chromium dioxide, with which the magnetic head is intended to have effective intimate contact
  • the surface of the recording medium usually does not have the desired, perfect geometric profile for establishing such effective intimate contact for any location on the recording surface.
  • the surface of the recording medium typically contains imperfections including bumps and seams in the recording material itself, and contamination by foreign matter, such as dust and toner particles which, even with the provision of cleaning devices such as vacuum knives, may not be perfectly removed.
  • imperfections on the surface of the recording medium may, depending upon drum rotational speed, constitute a source of degradation in both the image quality and the physical surface of the drum and/or the recording head during the movement of the drum past the head. Not only are imperfections on the drum surface a cause of head bounce, but because the head is under pressure to maintain contact (and thereby maximum magnetic coupling) between head and drum, both the head and the drum are subject to wear, and plate-out (the disposition of magnetic medium onto the magnetic head) may occur.
  • the head can slide on the chromium dioxide layer without causing damage and without losing contact with the recording surface, so that the imperfections are not a serious problem.
  • the aerodynamic bearing that is created by the high relative rotational velocity between the recording surface and the head can be utilized in conjunction with the high quality medium to diminish the above problems.
  • imperfections in the drum surface cannot be ignored, but instead, subject the imaging process to the above-mentioned drawbacks.
  • OMPI hydrodynamic magnetographic imaging technique that provides the intended effective intimate contact between the recording head and the magnetographic recording surface.
  • a liquid e.g. water
  • a liquid bearing against which the recording head is urged is applied to the surface of the drum slightly upstream of the location of the recording head, so as to create a liquid bearing against which the recording head is urged, and thereby intimately magnetically coupled with the surface of the drum, except for an extremely thin liquid film between the head and drum surface.
  • the bearing is generated by a simplified sponge/squeegee water applicator that rests on the drum upstream of and adjacent to the recording head.
  • Water is supplied to the sponge from a fluid inlet line, to create a trickle flow from the sponge.
  • This trickle of water is converted into a thin film by a squeegee blade that rests against the drum.
  • the fluid inlet line may be positione to be selectively pinched and relaxed by the mechanism that displaces the recording head relative to the recording surface.
  • Figure 1 depicts a schematic side view of a magnetographic recording apparatus employing the hydrodynamic imaging device of the present invention
  • FIG 2 is an enlarged illustration of the details of the li-quid bearing applicator shown schematically in Figure 1;
  • Figure 3 is an exaggerated illustration of the coupling of a magnetic recording head and a fluid bearing on the surface of a recording medium.
  • FIG. 1 a general schematic side view of a magnetographic recording apparatus employing the hydrodynamic imaging device of the present invention.
  • Such an apparatus may include a single station both imaging (recording) and reproduction (hard copy generation) , as is conventionally employed in both ele ⁇ trographic and magnetographic apparatus (as described in the above-referenced Edwards el al patent) , cr it may employ a multiple station arrangement, such as described in copending patent application Serial No. , filed , entitled “Transfer Mechanism for Multiple Magnetographic Imaging/Recording Apparatus", by , and assigned to the Assignee of the present application.
  • imaging station and printing station are separated from one another with the multiple magnetographic drums being interchanged between the two stations for the separate functions performed thereby, as described in the above-identified copending application.
  • the schematic illustration of the configuration of the recording station may be simplified since the details of the printing sector (decorator, web transfer mechanism, etc.) are unnecessary for an understanding of the present invention and, accordingly, are not shown or described here.
  • a recording drum 10 is shown as being rotatable in a clockwise direction R by a suitable drive mechanism (not shown) about the axis 8 of a drum axle 11.
  • the surface of drum 10 is made of magnetically responsive recording material, such as a layer of chromium dioxide, as is standard practice in the art.
  • Circumferentially disposed around drum 10 are a record head 14, cleaning station 15 and an erase head 23.
  • These components, per se, are of conventional configuration (e.g. clean station 15 includes the usual roller brushes, vacuum knives, magnet pick-up elements etc.) and not, per se, constituting the present invention, will not be described in detail here. They are shown simply to illustrate some of the components of a magnetographic recording environment, familiar to the skilled artisan, in which the present invention may be employed.
  • Recording head 14 is displaceable, in a radial direction relative to the axis of drum 10, toward and away from surface 12 by a head positioning mechanism 17. As described briefly above for the record mode magnetic recording head 14 is urged by head positioning mechanism into effective intimate
  • OMPI contact with the surface 12 of drum 10, whereby information signals that are coupled to head 14 may be recorded on surface 12 in the form of modulated magnetic regions in the chromium oxide layer representative of those information signals.
  • a liquid bearing applicator 16 Adjacent to and upstream (in terms of direction of rotation R of drum 10) of magnetic recording head 14 is a liquid bearing applicator 16 (shown in detail in Figure 2, described below) which creates a liquid bearing between head 14 and surface 12 so that the degree of coupling between the transducer surface of head 14 and surface 12 may be significantly improved compared to conventional schemes wherein no such bearing is provided.
  • Applicator 16 is coupled to a liquid supply source 13 by way of a fluid supply line 21, through which the bearing liquid (e.g. water) is supplied, as by gravitational flow.
  • the bearing liquid e.g. water
  • flow line 21 may be mechanically coupled with head positioning mechanism 17 so that water flow therethrough is selectively controlled in response to the displacement of head 14 relative to surface 12.
  • the details of the liquid bearing applicator are shown as including a sponge 31 and a squeegee rubber strip 32 against which sponge 31 abuts, so that water released thereby will be directed onto the surface 12 of drum 10 to form a thin liquid bearing 51 that is carried past the position of recording head 14.
  • Water is supplied to applicator '14 from a water supply reservoir (not shown) , corresponding to source 13 of Figure 1.
  • sponge 31 becomes saturated and emits a trickle sufficient to create a thin film 51 by the action of squeegee rubber strip 32, the edge portion 36 of which rides on the water bearing 51 as it is carried along drum 10.
  • Head 14 Downstream of applicator 16 is the magnetic recording head 14.
  • Head 14 is affixed to one end of a flat spring or band 33, the other end of which is held by a rigidly-fixed support block 38.
  • Band 33 may comprise a strip of beryllium that is cantilevered at block 38 so that head 14, in turn, is supported in a cantilevered fashion at block 38.
  • Displacement of head 14 toward and away from surface 12 is accomplished by a positioning rod 42 which engages head 14 and is displaceable in a radial direction (relative to the axis of drum 10) by a drive motor 44 in the direction of arrows 47.
  • Positioning rod 42 engages a pinch bar 41 such that displacement of rod 42 causes a corresponding displacement of pinch bar 41.
  • a head support base 47 Disposed adjacent to but spaced apart from pinch bar 41 is a head support base 47 through which a guide pin 36 passes.
  • Water flow feed line 21 passes in a space or channel between support base 47 and pinch bar 41 so that in the position shown in Figure 2, line 21 is not constricted and water is permitted to flow through line 21 to the applicator 16.
  • drive source 44 is operated to retract recording head 14 away from drum 10
  • pinch bar 41 is displaced towards support base 47, whereby line 21 becomes constricted or pinched between pinch bar 41 and support base 47, to thereby interrupt the flow of water to applicator 16.
  • Such displacement of head 14 takes place subsequent to the record mode of operation of drum 10 prior to its use as a printing drum at a printing station (not shown) .
  • the pressure applied to head 14 is established to maintain the desired magnetic coupling (e.g. physical spacing) between the transducer surface of head 14 and surface 12 of drum 10. This may be on the order of an ounce or two of pressure provided by source 44 and beryllium band 33, so that a slight pressure is exerted on head in a direction normal to surface 12. This slight pressure is sufficient to keep head 14 riding on the bearing layer 51, but insufficient to override the back pressure of bearing layer 51, so that head 14 is prevented from actually touching surface 12.
  • the desired magnetic coupling e.g. physical spacing
  • Figure 3 shows an exaggerated (not to scale) illustration of head 14 as it rides on liquid bearing 51.
  • the thickness of the liquid film bearing 51 is controllable by means of the water flow from and the positioning of applicator 16 relative to surface 12 of drum 10.
  • the exact thickness of bearing 51 will depend, of course, on the rotational speed of drum 10 past the applicator 16 and head 14 and the quality of surface 12. These factors are readily established emperically based upon station size and configuration and need not be precisely determined prior to system set up.
  • water flow rate based simply upon the influence of gravity has been 12 found to provide a bearing that meets the performance objectives of the present invention.
  • bearing 51 as illustrated in Figure 3 not only provides a slight separation D between the transducer magnetic coupling face 56 of head 14 from the surface 12 to prevent contact between head 14 and imperfections in the surface 12, such as bump 61 and seam 62, but maintains foreign matter, such as a toner or dust particles 52, in solution, away from transducer face 56 and surface 12.
  • This latter action prevents a build up of foreign matter on these surfaces which would otherwise detrimentally affect the intended performance of the recorder, as mentioned previously.
  • some of the foreign matter that is carried by bearing 51 floats on the surface of the water and, over time, forms a "bathtub ring" 54 on the side surface of head 14.
  • this ring is at a location on head 14 that does not affect performance or cause wear of the head, and can be easily removed when the head itself is removed for cleaning.

Abstract

Les problèmes posés par l'usure et les rebonds provoqués par les imperfections de surface (12) d'un support d'enregistrement magnétique, tel qu'un tambour (10) recouvert de bioxyde de chrome, sont résolus grâce à une technique de mise en image magnétographique hydrodynamique qui assure le contact étroit désiré entre la tête d'enregistrement (14) et la surface d'enregistrement magnétographique (12). Un liquide (par exemple de l'eau) (51) est appliqué sur la surface du tambour (10) légèrement en amont de l'emplacement de la tête d'enregistrement (14), de manière à créer un palier liquide (51) contre lequel est sollicitée la tête d'enregistrement (14), cette tête étant ainsi couplée magnétiquement et intimement avec la surface du tambour, à l'exception d'une pellicule extrêmement mince de liquide (51) entre la tête (14) et la surface du tambour (12). Grâce à ce palier liquide extrêmement mince (51), il est possible d'appliquer une pression continue sur la tête (14), pour la maintenir en contact étroit effectif avec la surface (12) du support d'enregistrement, sans risquer de provoquer des éraflures sur le support ou l'usure de la tête (14).
PCT/US1984/001224 1983-08-02 1984-08-02 Procede et dispositif d'enregistrement magnetique hydrodynamique WO1985000918A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08506178A GB2153302B (en) 1983-08-02 1984-08-02 Method and apparatus for hydrodynamic magnetic recording

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US51975983A 1983-08-02 1983-08-02
US519,759 1983-08-02

Publications (1)

Publication Number Publication Date
WO1985000918A1 true WO1985000918A1 (fr) 1985-02-28

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ID=24069667

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1984/001224 WO1985000918A1 (fr) 1983-08-02 1984-08-02 Procede et dispositif d'enregistrement magnetique hydrodynamique

Country Status (5)

Country Link
JP (1) JPS60501923A (fr)
CA (1) CA1221164A (fr)
DE (1) DE3490368T1 (fr)
GB (2) GB2153302B (fr)
WO (1) WO1985000918A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0367510A2 (fr) * 1988-10-31 1990-05-09 International Business Machines Corporation Appareil et méthode d'enregistrement magnétique ou quasi contact
EP0384762A2 (fr) * 1989-02-24 1990-08-29 Conner Peripherals, Inc. Montage d'unité de disque mouillé avec palier à broche conique

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1221164A (fr) * 1983-08-02 1987-04-28 Andrew M. Bardos Methode et appareil d'enregistrement magnetique hydrodynamique
US5193046A (en) * 1988-10-17 1993-03-09 Conner Peripherals, Nc. Information recording apparatus with a liquid bearing

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2969435A (en) * 1955-02-07 1961-01-24 Ibm Oil film spacer for magnetic recording device
US3005675A (en) * 1956-02-08 1961-10-24 Lab For Electronics Inc Fluid bearing control for a magnetic head
DE1239354B (de) * 1957-11-28 1967-04-27 Zuse K G Vorrichtung zum Aufzeichnen bzw. Abtasten von Signalen auf Aufzeichnungstraegern

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1221164A (fr) * 1983-08-02 1987-04-28 Andrew M. Bardos Methode et appareil d'enregistrement magnetique hydrodynamique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2969435A (en) * 1955-02-07 1961-01-24 Ibm Oil film spacer for magnetic recording device
US3005675A (en) * 1956-02-08 1961-10-24 Lab For Electronics Inc Fluid bearing control for a magnetic head
DE1239354B (de) * 1957-11-28 1967-04-27 Zuse K G Vorrichtung zum Aufzeichnen bzw. Abtasten von Signalen auf Aufzeichnungstraegern

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0367510A2 (fr) * 1988-10-31 1990-05-09 International Business Machines Corporation Appareil et méthode d'enregistrement magnétique ou quasi contact
EP0367510A3 (fr) * 1988-10-31 1991-03-13 International Business Machines Corporation Appareil et méthode d'enregistrement magnétique ou quasi contact
EP0606963A2 (fr) * 1988-10-31 1994-07-20 International Business Machines Corporation Dispositif de stockage magnétique de données comportant un assemblage de transducteur pour enregistrement magnétique à quasicontact
EP0606963A3 (fr) * 1988-10-31 1997-04-23 Ibm Dispositif de stockage magnétique de données comportant un assemblage de transducteur pour enregistrement magnétique à quasicontact.
US5742449A (en) * 1988-10-31 1998-04-21 International Business Machines Corporation Near contact magnetic recording using a liquid lubricant bearing to separate media and transducer
US5850317A (en) * 1988-10-31 1998-12-15 International Business Machines Corporation Apparatus and method for near contact magnetic recording
EP0384762A2 (fr) * 1989-02-24 1990-08-29 Conner Peripherals, Inc. Montage d'unité de disque mouillé avec palier à broche conique
EP0384762A3 (fr) * 1989-02-24 1991-08-21 Conner Peripherals, Inc. Montage d'unité de disque mouillé avec palier à broche conique

Also Published As

Publication number Publication date
GB8506178D0 (en) 1985-04-11
CA1221164A (fr) 1987-04-28
GB2198690B (en) 1991-01-23
GB8630134D0 (en) 1987-01-28
GB2198690A (en) 1988-06-22
DE3490368T1 (de) 1985-10-17
JPS60501923A (ja) 1985-11-07
GB2153302B (en) 1988-03-09
GB2153302A (en) 1985-08-21

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