US3962724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and device for testing movable magnetic heads for ability to trace a predetermined spiral magnetic track without deviating therefrom
Assignee: Ricoh Co Ltd
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Filing: 1973-05-11
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Granted: 1976-06-08
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Expires: 1993-05-11
Abstract
Abstract A method of and a device using a testing sheet having magnetically recorded thereon a magnetic head deviation detection signal formed on a portion of a predetermined spiral magnetic track or on a portion of a predetermined spiral magnetic track and on at least one side of such one portion. By causing a magnetic head mounted on a turntable of magnetic recording and reproducing apparatus for magnetically recording and reproducing electric signals in a spiral track to move along the predetermined spiral track on the testing sheet which is fixed, it is possible to find out if the magnetic head is able to trace the predetermined spiral magnetic track without deviating therefrom.
Inventors
- 👤 Masami Koizumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:28
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/04; G11B21/043; G11B33/00; G11B33/10; G11B5/00; G11B5/008; G11B5/00804; G11B5/48; G11B5/58
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
241 words
A method of testing movable magnetic heads for ability to trace a predetermined spiral magnetic track without deviating therefrom for magnetic recording and reproducing apparatus wherein electric signals are recorded and reproduced in a spiral track, comprising the steps of a. magnetically recording a magnetic head deviation detection signal in a spiral signal track on a testing sheet for disposition of the signal on a first convolution of the predetermined spiral magnetic track and both sides of said first convolution, such that said spiral signal track has a width equal to the width of the predetermined spiral magnetic track plus the width of the two recordingless zones on both sides of said first convolution, and has an edge coincident with an edge of a convolution of said predetermined spiral magnetic track adjacent said first convolution; b. juxtaposing said sheet to a turntable carrying a magnetic head to be tested; c. operating the turntable and head for tracing of the detection signal by the head and production of output power representative of the signal as detected by the head, the operating step including moving the head in a radial direction with respect to the axis of turntable rotation during tracing of the detection signal by the head; and d. detecting the produced output power level to determine deviation of the head from the predetermined spiral track as represented by departure of said output power level from a predetermined relation to said signal.
Claim 2
Independent Claim
241 words
A method of testing movable magnetic heads for ability to trace a predetermined spiral magnetic track without deviating therefrom for magnetic recording and reproducing apparatus wherein electric signals are recorded and reproduced in a spiral track, comprising the steps of a. magnetically recording a magnetic head deviation detection signal in a spiral signal track on a testing sheet for disposition of the signal on a first convolution of the predetermined spiral magnetic track and both sides of said first convolution, such that said spiral signal track has a width equal to the width of the predetermined spiral magnetic track plus the width of the two recordingless zones on both sides of said first convolution, and has an edge coincident with an edge of a convolution of said predetermined spiral magnetic track adjacent said first convolution; b. juxtaposing said sheet to a turntable carrying a magnetic head to be tested; c. operating the turntable and head for tracing of the detection signal by the head and production of output power representative of the signal as detected by the head, the operating step including moving the head in a radial direction with respect to the axis of turntable rotation during tracing of the detection signal by the head; and d. detecting the produced output power level to determine deviation of the head from the predetermined spiral track as represented by departure of said output power level from a predetermined relation to said signal.
Claim 3
Independent Claim
175 words
A device for testing movable magnetic heads for ability to trace a predetermined spiral magnetic track without deviating therefrom for magnetic recording and reproducing apparatus wherein electric signals are recorded and reproduced in spiral track, comprising a testing sheet having magnetically recorded thereon a magnetic head deviation detection signal formed in a spiral signal track on a first convolution of the predetermined spiral magnetic track and both sides of said first convolution, said spiral signal track having a width equal to the width of the predetermined spiral magnetic track plus the width of the two recordingless zones on both sides of said first convolution, and having an edge coincident with an edge of a convolution of the predetermined spiral magnetic track adjacent said first convolution, and means for detecting an output power level of a movable magnetic head to be tested when said magnetic head is caused to trace the deviation detection signal by being carried on a rotating turntable while being moved in a radial direction with respect to the axis of turntable rotation.
Claim 4
Independent Claim
175 words
A device for testing movable magnetic heads for ability to trace a predetermined spiral magnetic track without deviating therefrom for magnetic recording and reproducing apparatus wherein electric signals are recorded and reproduced in spiral track, comprising a testing sheet having magnetically recorded thereon a magnetic head deviation detection signal formed in a spiral signal track on a first convolution of the predetermined spiral magnetic track and both sides of said first convolution, said spiral signal track having a width equal to the width of the predetermined spiral magnetic track plus the width of the two recordingless zones on both sides of said first convolution, and having an edge coincident with an edge of a convolution of the predetermined spiral magnetic track adjacent said first convolution, and means for detecting an output power level of a movable magnetic head to be tested when said magnetic head is caused to trace the deviation detection signal by being carried on a rotating turntable while being moved in a radial direction with respect to the axis of turntable rotation.
Claim 5
Dependent Claim
60 words
A device according to claim 2, wherein said testing sheet has said magnetic head deviation detection signal recorded on a first convolution and a third convolution of the predetermined spiral magnetic track, a portion of said deviation detection signal recorded on the first convolution differing in frequency from a portion of said deviation detection signal recorded on the third convolution.
Claim 6
Dependent Claim
39 words
A device according to claim 2, wherein said means for detecting an output power of a movable magnetic head to be tested is a recorder adapted to automatically record the output of said magnetic head on a recording sheet.
Claim 7
Dependent Claim
211 words
In combination with a magnetic head, means carrying said magnetic head for advance thereof along a spiral path, and means for holding a magnetic sheet in a position for tracing of a spiral magnetic recording track thereon by said head, a device for detecting deviation of the head from a predetermined spiral magnetic track during advance of the head, said device comprising a. a testing sheet having recorded thereon a magnetically detectable deviation signal in a spiral signal track positioned on a first convolution of the predetermined spiral magnetic track and both sides of said first convolution, such that said spiral signal track has a width equal to the width of the predetermined spiral magnetic track plus the width of the two recordingless zones on both sides of said first convolution, and has an edge coincident with an edge of a convolution of said predetermined spiral magnetic track adjacent said first convolution, for mounting in said holding means to be traced by said head; and b. means for detecting the output power level of said head when the head traces said deviation signal on said testing sheet as the head is carried on a rotating turntable while being moved in a radial direction with respect to the axis of turntable rotation.
Claim 8
Dependent Claim
211 words
In combination with a magnetic head, means carrying said magnetic head for advance thereof along a spiral path, and means for holding a magnetic sheet in a position for tracing of a spiral magnetic recording track thereon by said head, a device for detecting deviation of the head from a predetermined spiral magnetic track during advance of the head, said device comprising a. a testing sheet having recorded thereon a magnetically detectable deviation signal in a spiral signal track positioned on a first convolution of the predetermined spiral magnetic track and both sides of said first convolution, such that said spiral signal track has a width equal to the width of the predetermined spiral magnetic track plus the width of the two recordingless zones on both sides of said first convolution, and has an edge coincident with an edge of a convolution of said predetermined spiral magnetic track adjacent said first convolution, for mounting in said holding means to be traced by said head; and b. means for detecting the output power level of said head when the head traces said deviation signal on said testing sheet as the head is carried on a rotating turntable while being moved in a radial direction with respect to the axis of turntable rotation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-08 | 1979-12-08 | 1980-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-08 | 1983-12-08 | 1984-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-08 | 1987-12-08 | 1988-06-08 | $7700.00 | Window Closed / Lapsed |