PURPOSE: To improve the traveling characteristics and sensitivity by incorporating carbon black of specified particle sizes into the magnetic layer on the support.
CONSTITUTION: A magnetic layer is formed by coating a magnetic coating material contg. carbon black of 30W50mμ average particle size and carbon black of 10W30mμ or 50W120mμ average particle size. Carbon black of 30W50mμ average particle size is mixed with a binder and a lubricant to increase the strength, and it is used in combination with carbon black of 10W30mμ or 50W120mμ average particle size to improve peculiarly the traveling characteristics and video output. The preferred total amount of carbon black used is 0.05W20pts.wt. per 100pts.wt. magnetic powder, and the preferred mixing ratio between carbon black of 30W 50mμ average particle size and carbon black of 10W30mμ or 50W120mμ average particle size is 10/90W90/10.
MIYOSHI TAKAHITO
FUJIYAMA MASAAKI
TADOKORO EIICHI
