Patent ID: 7031087

Claim:
A servo writer for writing a servo signal on a magnetic tape which is fed out from a feeding reel and taken-up by a take-up reel, the servo writer comprising: a writing head that writes a servo signal on the magnetic tape; an inspection head which is formed on the downstream side of the writing head and reads the servo signal written on the magnetic tape for inspection; a servo signal inspection part that inspects the servo signal read by the inspection head; and a current amount control part that controls an amount of a record current supplied to the writing head based on the inspection result in the servo inspection part; wherein based on a value obtained by moving average processing of the output of the servo signal read by the inspection head, the existence of the writing error of the servo signal written on the magnetic tape is inspected, and wherein the servo signal read by the inspection head and a reference servo signal are compared, to thereby inspect the existence of a writing error of the servo signal written on the magnetic tape.