| 摘要 |
<p>The present invention relates to a magnetic tape driving device of a magnetic recording and reproducing apparatus designed to cause an idler gear (1) to be in rotating contact with a take-up reel (5) or a feed reel (4) according to a rotational direction related to operation of a driving gear (2) when a magnetic tape is driven forward or rewound quickly, thereby selectively to transmit the driving force of the driving gear (2) to the take-up reel (5) or feed reel (4) through the idler gear (1). When the idler gear (1) is in rotating contact with the take-up reel (5) or feed reel (4) a control portion (8) detects that FG pulses of both the take-up reel and feed reel are generated from FG pulse generating portions (7, 6) provided at both the take-up reel and feed reel, that is, the control portion (8) detects that both reels are rotating, and confirms that the rotating contact of the idler gear (1) with take-up reel (5) or feed reel (4) has been completed normally. If an FG pulse of only one reel is generated, that is, when only one reel is rotating, or when FG pulses of neither reel are generated, that is, when neither reel is rotating, the control portion (8) judges that faulty rotating contact of the idler gear with the take-up reel or feed reel has occured and issues a command to the idler gear driving portion (11) to return the idler gear (1) to a position where it does not contact the driving gear (2) so that the operation of rotating contact of the idler gear (1) with the take-up reel (5) or feed reel (4) is attempted again. According to the above arrangement, it is made possible to prevent irregular movement caused by the occurrence of reverse rotating contact or mechanical lock when the idler gear (1) is being brought into rotating contact with the reel.</p> |
