COPYING DEVICE

PURPOSE:To simplify a copying operation by detecting the rotational number of a counter roll which is revolved in response to the tape driving speed as well as the rotational number of a supply reel for slave tape and at the same time detecting the thickness of the slave tape to know an amount of the remaining tape at the supply side. CONSTITUTION:Both start and end cue signals of a master tape MT are detected by a reproduction head 21 when the 1st copying action is carried out to a slave tape ST. A CPU25 knows the recording time Lo of a program from the number of pulses given from an FG23 and records it. At the same time, the thickness of the ST is obtained from the program time and stored. Then both the MT and a drive tape DT are rewound to perform the 2nd copying job. The CPU25 calculates the wind diameter of the remaining ST from the rotational number Nc of a supply reel of the ST, the rotational number Mk of a counter roll 22 and the pulses supplied from both FG 23 and 24. Then a remaining tape amount L is calculated from the limit wind diameter of tape and the thickness of the ST. Thus the remaining copy amount is displayed on a display device 24 through the calculation of L/Lo.