Magnetic head cleaning tape and method
AssigneeMinnesota Mining and Manufacturing Company
InventorsJohn V. Nowicki, John D. Hakanson
Life of this patent
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Abstract
Magnetic heads of color video tape recorder (vtr) machines are cleaned without harmful abrasion by means of a novel magnetic head cleaning tape carrying a color bar signal. Abrupt appearance of the color bar test pattern at the video monitor permits cessation of the cleaning operation immediately upon complete removal of foreign matter and without harmful abrasion of the heads.
Claims7
Method of cleaning the magnetic heads of a video tape recorder having a video monitor, comprising playing in said recorder a magnetically recordable magnetic head cleaning tape having a surface coating comprising magnetizable particles in a hard non-magnetizable binder, said coating having an H.sub.c value of at least 300 oersteds and a B.sub.r value of at least 800 gauss, and having a surface roughness of between 5 .times. 10.sup.-.sup.2 and 12 .times. 10.sup..sup.-2 (arithmetic average) and between 20 .times. 10.sup..sup.-2 and 47 .times. 10.sup..sup.-2 (peak-to-valley) micro-meters, and said tape carrying a magnetically recorded video test pattern;
- continuing the play until the display produced on said video monitor resolves into the clear synchronized test pattern;
- and then immediately stopping play.
As a new article of manufacture, a magnetic head cleaning tape product including a carrier having bonded thereto a coating comprising magnetizable particles in a hard non-magnetizable binder, said coating having an H.sub.c value of at least 300 oersteds and B.sub.r value of at least 800 gauss, and having a surface roughness of between 5 .times. 10.sup..sup.-2 and 12 .times. 10.sup..sup.-2 (arithmetic average) and between 20 .times. 10.sup..sup.-2 and 47 .times. 10.sup..sup.-2 (peak-to-valley) micro-inches;
- and said tape carrying a magnetically recorded video test pattern.
Dependencies are inferred from the claim text.