| 摘要 |
To print on a magnetic tape (2) time marks magnetically recorded on one track of the tape, this tape is moved past a magnetic head (7) by means of a capstan (10). At the output of the capstan, the tape goes through a printer (19). The signals read by the magnetic head are worked out and decoded by an electric device (31). The decoded signals are input in the printer for the control of the printing characters. The length or portion of the run of the magnetic tape, passing through the printer, is delimited by a compensation roller (14) and a pressure roller (16) which subject the tape to a direction change of 180` thereby creating a compensation loop and a standby loop. The compensation roller has a reciprocating motion in the direction of said portion and in the opposite direction. During the printing process, the compensation roller is moved with a uniform speed, half of the travelling speed of the tape driven by the capstan, in the direction opposite to that of said portion, which causes a temporary stop of the tape and thereby an increase of the compensation loop and a decrease of the standby loop. The compensation roller is arranged at the extremity of a lever of which the other extremity engages an excentric-sheave driven temporarily in synchronism with the capstan. A lifting electromagnet, reacting to the control signals generated by the electronic device, achieves a fixed coupling in rotation between the excentric-sheave and the driving axis of the capstan during the printing process. |
