DE3439562A1 - METHOD FOR DETACHING A MAGNETIC (COATING) MEDIUM FROM A PLATE OR DISC - Google Patents

Description

Henkel, Pfenning, Feiler, Hänzel & Meinig ^ ι

Magnetic Peripherals Inc. Minneapolis. Minn., U.St.A. Patent attorneys

European Pale "! Attorneys Approved representatives in front of the European Faientanr:

Dr phr G He-iKe! Munich Dip! -I ¹ Xj J Pferdv-.ng Be'nr Dr rer fiat L Feler. Mj'icner, Dipi-lng W Hanzei Munich Dipi -Pnys. K. H Me!. Tig. Be ^r iin D 'Ing Ä Butenschon Berlin Dipl.-Ins D. Kc'. · "· .. ·· '·, <"-.-.': -

Mohlstrasse 37
D-8000 Munches. 8Q

Tel 089 / 982085-87 Telex 05298C2hnk; d

Teie: ax (G ^r 2- + 3 ·.
089-'9814

MPI öi + 8-üJG

How to remove a magnetic (Coating) medium from a plate or disk

The invention relates to a process for detaching a magnetic (coating) mediuraB from a plate or disk.

The detachment (removal) of such media from a disk or disk (e.g. recording medium disk) up to now has typically been done mechanically powered brushes and solvents. In some FBIlBn even had to be sanded slightly.

Disadvantages of this procedure are complex and time-consuming processing of the plates or Disks, additional material, labor and equipment costs and contamination of the plate or disc with the release solvents.

Optionally, the medium can be removed from the plate or disk using a solvent spray be detached while the plate or disc is still on the loading machine. The disc or plate are compared with At high speed (about 2000 rpm), a short acetone spray jet is applied to the inside diameter of the plate or disk and then immediately the entire surface by the operator the disc or plate with a lint-free cloth soaked in acetone. Some of the shortcomings of this approach are as follows: When the acetone spray hits the inside diameter the disk or plate (hereinafter simply referred to as plate) is directed, flows in Part of the acetone inevitably goes under the hub cover and to the other side of the plate to get the Partially peel off the coating on the opposite side of the panel; hat often occurs

Contamination of the plate by acetone; on

* 0 >,
The surface of the plate can form small droplets of ΙϊΙββββγ due to condensation due to the excessive cooling of the plate during the evaporation of the acetone, whereby these droplets then form coating banks (runs) and streaks; the surface of the plate can be scratched when wiped.

The invention relates to a method for detaching (removing) a magnetic (coating) Medium from a disk in which, after finding a flaw in a panel and, prior to curing (i.e., burn-in) thereof, the panel

rotated at high speed and new 15

(BBBChichtungB-) Mediura from a DQse onto the plate is discharged, whereby the DQse is calibrated from the outside diameter the plate is moved to its inner diameter. Application pressure of the coating medium and

The speed of the disk will be as high or high as 20

kept that the new coating medium flow the old medium "washes away". When the DQse moves from the inside to the outside diameter, a new medium layer applied to the plate.

The following is a preferred embodiment

beiapiel of the invention explained in more detail with reference to the drawing. Show it:

Fig. 1 is a perspective view of a device with which the inventive Let process feasible,

Fig. 2 is a graph of the spindle speed depending on the time to ver

clarification of the steps of the invention Procedure,

3 shows a chemical side view of the plate listening to the dozing movement from the outside to the Inner diameter with normal observation

occurrence,

1 * a representation similar to FIG. 3 during the backward movement of the nozzle from the inner to the outer band diameter for the purpose of applying a new observation amadium layer during the normal observation process and

FIG. 5 shows a representation similar to FIG. 3 for illustration purposes of the invention

Löaever procedure, in which aich the nozzle for

Stripping or peeling off the original

Attention center discrepancy from panel moved from the outer to the inner diameter.

Fig. 1 illustrates in a simplified representation one for the implementation of the invention Proceeded suitable plate or disc coater 1, in which only the general structure is appropriate for the invention, why the details of the device 1 are not shown in more detail. The device has a rotatable spindle 5, the variable speed from bia to at least, for example, 3800 / min a drive, not shown, can be driven iat.

A plate (or disk) 10 on which the

magnetic medium are applied aoll, has a central opening (center hole) 12, which with With the aid of a suitable mechanism for co-rotation with the spindle 5, it can be connected to this.

The plate 10 has an inner diameter Ak and an outer diameter 15, the one

Define concentric area 16 of plate 10 on which the magnetic medium is applied target. One a magnetic (coating) medium dispensing nozzle 20 is carried by an arm 25 which in turn is not under the control of a control device shown is rotatable by a motor. The arm 25 includes a not shown Fluid line that connects the nozzle with a pressurized supply (not shown) for the flowable magnetic medium connects. In a preferred embodiment, the Discharge opening at the tip of the nozzle 20 a width of about 0.51 mm. The arm is by means of the 3D motor. in the direction of the arrows 27, 28 rotatable so that the can 20 from the outer diameter 15 to the inner diameter 11 »and back again. The control device for the motor 30 determines the speed of deflection of the nozzle 20 over the plate 10. To change the discharge pressure of the nozzle 20 can

a corresponding mechanism can be provided.

In Fig. 2, the method for coating the plate is illustrated in the form of a graphical representation of the plate or spindle speed as a function of time. This process is described in DE-OS P 3k 07 253.5. This process begins with a solvent cleaning step 50, during which the platter is spun at (about) 2300 rpm for (about) 10 seconds while lightly tapping to clear its surface of airborne particles and other particles a lint-free or lint-free cloth soaked in a cleaning solution is wiped off. It is assumed that this cleaning process in the future due to better disk handling or

machining operations before placing the plate on the spindle 5 can be omitted. Immediately after this cleaning step 50, the disk speed becomes in a step 52 approximately β - 9 a to at least 5

increased about 2500 / min, the nozzle 20 the magnetic medium with a can discharge pressure of about 0.42 - 0.56 bar (measuring pressure), and although starting at the outer diameter 15 in the direction on the inner diameter 14 for about 1 s on Inner diameter 14 persistently and then with a deflection speed of about 30.5 mm / s to Outside diameter 14 returning.

3 and 4 illustrate the application of the liquid or flowable magnetic Medium on the plate 10 during the step The flowable medium breathes iron oxide particles, the Bind suspended in a polymeric binder mass. When moving the nozzle 20 According to FIG. 3, an extremely thin layer adheres from the outer diameter 15 to the inner diameter 14 (Film) of the medium 70A on the plate surface, while an excess (non-stick)

Medium layer 60 from the point of movement 90

flows radially outwards to and above the outer diameter 15 and then flows down from the plate due to the centrifugal force generated at the high speed of the plate 10. By the rotation of the plate it at high speed _m is ensured that only a very thin layer of the medium 7OA adheres to the plate; this also ensures that the protective layer 80 D extends over the entire concentrically shaped plate surface which lies radially outward from the point of movement 90 of the nozzle 20. When moving the

Nozzle ZO from outside diameter 15 to inside diameter The excess layer 60 is effective magnetic medium ala protective layer, which is a

Evaporation of the underlying layer 7OA and

prevents rapid changes in viscosity of the same. If the DQse 20 has the inner diameter 11 » reaches it, hold it for a short time (about 1 a long) to ensure that the edge of the layer 7OA from the magnetic medium on the inner diameter

14 is well defined. The DQae 20 then moves back in the radial direction outwards to the outer diameter measurer 15. When the RQckbewegung DQse 20 for AuBendurchmesser 15 is governed according to Fig displaced. K

the protective layer 60 also to the outside diameter 15th

15 back, with the thin layer 7OB of the

magnetic medium exposed to the outside air will. As mentioned, the speed of movement is of the DQse 20 about 30.5 mm / s. As soon as the DQse

has reached the outer diameter of 15, the plate 20th

directly according to the magnet orientation step Fig. 2 is supplied, in which the speed of the plate for a time 10-15 s to about 52 / min is reduced while the plate 10 is exposed to an orienting magnetic field. Here it should be noted that the plate 10 the orienting magnetic field only a few seconds after the first A portion of the thin layer 7QB exposed to atmospheric air. Consequently there is only minimal evaporation and the slightest changes in viscosity between the point in time that the magnetic medium is applied to the plate 10 for the first time and comes into contact with the outside air arrives, and at the beginning of the

process on. As a result, the magnet 35

Particles of the thin magnetic layer 70B much lighter along the lines of force the orienting

Orient the magnetic field, ala this with the previous ones Process was possible this guarantees a plate with a higher GCte.

A great deal occurs on the orientation process 54 short drying process or step 56, in which the plate 10 in the absence of the orienting Magnetic field to accelerate drying not rotated for more than 5 s at about 2300 / min will. The layer 70B from the magnetic medium produced by the method described is significantly thinner (0.25-0.51 mm) than the layer that can be produced using the previous method (Minimum thickness: 0.76 mm). As a result, the 7QB layer dries much faster than the previous ones Process so that the drying step 56 can be substantially shortened and even omitted can.

The following is the method according to the invention described for detaching a magnetic medium.

FIG. 5 illustrates the disk 10 with the layer 70B of the magnetic medium adhered to it. If the operator finds a coating error after coating the plate with the layer 70B notices, the plate can be according to the invention Method freed from the layer 70B and coated again. In this procedure the plate 10 is set in turn at high speed (at least 2500 / min) in rotation while by means of the

DQee 20 pressurized, flowable

magnetic medium is applied to the plate 10

will. The discharge pressure of the medium is approximately Q ₁ IfZ-O ₁ Se bar (measuring pressure). The discharge of the flowable medium begins outside the

diameter 15 of the plate 10, becomes the inner diameter-5

Better 1 ** continued and finally ends

outside the outer diameter 15 of the plate 10. During the inward movement of the nozzle 20 takes place the draining process during their outward movement the new layer of magnetic medium is applied. This means that simply using the Step 52 described in FIG. 2 is repeated. The application nozzle 20 moves towards the inner diameter of the plate 14 moves, becomes with an uninterrupted

Jet of pressurized, flowable 15

magnetic medium the previous coating layer

7OB dissolved and washed away, leaving the aluminum substrate underneath for a new application Layer from the magnetic flat medium is exposed. When moving the nozzle 20 to 20th

The excess medium 80 becomes outer diameter 15

continues to be thrown off the plate 10, while the new coating layer is applied to the one shown in FIG Ueise spreads out towards the outer diameter 15. The plate 10 is then in turn the 25th

Orientation step 5k and drying step 56,

as described with reference to FIG. 2, subjected.

As a result, defective (recording triger) disks simply be recoated without applying solvent or any mechanical wiping having to fall back. The discontinuation of the previously used vision replacement procedures will result in addition to a significantly shorter processing time. There is an interesting feature of the procedure

in that ea can be repeated any number of times until finally a satisfactory one (after visual inspection) Plate is obtained.

Of course, different things to the person skilled in the art Changes and modifications are possible without departing from the scope of the invention.

Claims (1)

Claims 1. Technique for stripping a magnetic (coating B-) Hediun from a disc or Plate with an outer and an inner diameter, characterized in that the plate dO) with a speed of at least 2500 / min set in rotation and a jet of the magnetic medium by means of a nozzle (2Q) a layer of the magnetic medium already on the disk, based on the outer diameter (i5) and progressing towards the inner diameter (1 <t) of the plate so that the previous layer of the magnetic medium is peeled off (removed) from the plate while the DQse discharging the medium jet from the outer to the inner diameter emotional. 2. V / experience according to claim 1, characterized in that that the DQse after its movement from the outer to the inner diameter for the purpose of detachment of the the previous layer of the magnetic medium is returned from the inside to the outside diameter, to apply a new layer of the magnetic medium to the plate. 3. A method according to claim 2, characterized marked ₃ records q that the magnetic medium is liable for the movement of the nozzle from the AuBenzum inner diameter during the layer-AblBsevorganga a thin layer to the plate and a protective layer of excess medium due to the centrifugal force of the rotating plate over the thin layer -2- radially outward from the nozzle flows, with the protective layer extending from the inside to the outside diameter as soon as the nozzle reaches the inside diameter reached, and with the nozzle to the outside nesaer relocated and exposes a new layer of the magnetic medium to the outside, while the nozzle moves from the inside to the outside diameter emotional. U. V / experienced according to claim 3, characterized in that the nozzle is stopped after its movement from the outer to the inner diameter during the layer peeling process for a period of about 1 β before aie is returned from the inner to the outer diameter. 5. The method according to claim 1, characterized in that that the discharge pressure of the flow of the magnetic medium from the nozzle is at least 0.35 bar (measuring pressure). 6. V / experience according to claim 1, characterized in that that the can is a when moving from the outer to the inner diameter with a speed of movement of 25.1 * -38.1 mm / s is performed. 7. The method according to claim 1, characterized in that that after the Schlcht purging process and applying a new layer of the magnetic Medium during the nozzle movement from inside to outside 35 diameter of the plate reduces the speed of the plate set and the latter is exposed to an orienting magnetic field in an orientation process. 8. The method according to claim 7, characterized in that that a drying process is carried out immediately after the orientation process, in which the speed of rotation of the plate is increased to accelerate the drying of the layer.