JPH02265064A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To quickly and surely detect an accident by providing a revolution speed comparing means, and deciding a fact that a sticking accident of a tape is generated, when the detected speed of revolution exceeds a set value. CONSTITUTION:To a revolution speed comparing circuit 3, a reference frequency for giving the speed of revolution of a normal reel base 1 is set in advance at every tape running mode. When a tape is drawn out of a cassette half, a supply reel of the reel base 1 rotates in proportion to a draw-out speed. Subsequently, the speed of revolution is detected by a reel base revolution speed detector 2 and converted to a prescribed frequency signal, and sent to the circuit 3. The circuit 3 compares the reference frequency and the signal from the circuit 2, and when it exceeds a reference signal, it is decided that a tape is stuck to a drum. Next, a sticking detecting signal is sent out to a system controller, and by applying the brake to the reel base 1, a drum motor 9 is stopped. In such a way, an accident is detected quickly and exactly, and it is prevented that the tape is caught in the drum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary head type magnetic recording and reproducing apparatus such as an R-DAT, a VTR, and an 8 mm video.

[Conventional technology]

In a rotary head type magnetic recording/reproducing device, if dew condensation occurs on the rotary head drum (hereinafter referred to as drum) or the tape, the tape will stick to the drum and be rolled up, causing problems such as damage to the tape. Conventionally, in order to prevent such tape sticking accidents, a condensation sensor was installed near the drum, and when condensation was detected by the condensation sensor, the brakes were applied to the reel stand at the same time.
The drum was configured to stop so that the tape would not get caught.

[Problem to be solved by the invention]

However, when using the above-mentioned dew condensation sensor, it has the disadvantage that it is difficult to detect when there is condensation on the tape side, and there is a problem that it is not possible to detect all tape sticking accidents. Ta.

The present invention has been made based on the above-mentioned circumstances, and provides a rotating head type magnetic recording and reproducing device that can quickly and reliably detect tape sticking accidents by comparing the rotation speed of a reel stand with a reference rotation speed. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the present invention provides a reel stand rotation speed detection means for detecting the rotation speed of a reel stand, and a normal tape that is set in advance to the reel stand rotation speed detected by the reel stand rotation speed detection means. and a rotation speed comparison means for comparing the rotation speed with a reference rotation speed giving a feed speed and detecting a tape sticking accident when the reel base rotation speed exceeds the reference rotation speed, and the rotation speed comparison means detects a tape sticking accident. When a collision is detected, the brakes are applied to the reel stand and the drum motor is stopped.

Further, the reference rotation speed set in the rotation speed comparison means is changed depending on the tape running mode, so that all tape running modes can be automatically supported.

[For production]

If the tape sticks to the drum due to condensation, etc., the drum rotates at high speed and the tape is pulled out at a higher speed than normal. The reel stand rotation speed detection means detects the tape withdrawal speed at this time, that is, the rotation speed of the reel stand, and sends it to the rotation speed comparison means.

The rotation speed comparing means compares the reel stand rotation speed sent from the reel stand rotation speed detection means with a reference rotation speed that provides a normal tape feeding speed, and detects when the reel stand rotation speed exceeds the reference rotation speed. It detects a tape sticking accident and applies the brakes to the reel stand and stops the drum. Therefore, a tape sticking accident can be detected regardless of where the condensation occurs.

Furthermore, the value of the reference rotation speed set in the rotation speed comparison means is adjusted according to the tape running mode at the time, such as threading mode, play mode such as recording/playback, n times speed search mode (FF, REW), etc. By changing this, all tape sticking accidents can be detected in all tape running modes.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, ■ is a reel stand on which a cassette tape is loaded, 2 is a reel stand rotation speed detector that detects the rotation speed of the supply reel side of reel stand 1 and outputs a frequency signal proportional to the rotation speed, and 3 is a reel stand rotation speed detector. A rotation speed comparison circuit detects a tape sticking accident by comparing the frequency signal output from the reel stand rotation speed detector 2 with a reference frequency signal that gives a reference rotation speed at a normal tape feeding speed; 4 is a system controller; , 5 is a reel stand brake drive circuit, 6 is a brake mechanism, 7 is a drum servo circuit, 8 is a motor drive circuit, and 9 is a drum motor.

The rotation speed comparison circuit 3 is prepared in advance with a reference frequency signal that gives a normal reel stand rotation speed for each tape running mode, and the current tape running mode is set in accordance with the tape running mode signal sent from the system controller 4. The configuration is such that the reference frequency signal is selected according to the reference frequency signal.

For example, taking the case of RDAT, if a sensor that outputs 8 pulses per rotation is used as the reel stand rotation speed detector 2, the reference frequency signal that gives the normal reference rotation speed of the reel stand 1 will be , in play mode -2,7
1 Hz, -28.6 Hz in 16x speed mode, -41, 1 Hz in threading mode, etc. are set in advance. Note that since the reel rotation speed changes within a certain range according to the diameter of the tape wound on the supply reel, each of the above reference frequency signals gives the maximum value of the range of change in the reel rotation speed in each tape running mode. A frequency that is larger than the frequency by a predetermined value is selected.

Next, the operation of the first embodiment will be explained.

When an operation key (not shown) is pressed and a predetermined operation command, such as a tape playback command, is given to the system controller 4, the system controller 4 drives a threading mechanism (not shown) to thread the thread onto the reel stand 1. Pull out the tape from the installed cassette half and start slending.

At the same time, a threading mode signal is sent to the rotation speed comparison circuit 3. Further, in parallel with these operations, the drum servo circuit 4 is operated to start servo control so that the drum motor 9 reaches a specified rotation speed, for example, 200 rpm.

The rotation speed comparison circuit 3 receives the threading mode signal from the system controller 4, and selects a reference frequency signal -41.1Hz corresponding to the current tape running mode, that is, the threading mode, from among the reference frequency signals corresponding to each of the tape running modes described above. is selected and the frequency signal is set as a reference frequency signal for detecting a tape sticking accident in the rotation speed comparison circuit 3.

When the tape is drawn out from the cassette half by the start of the threading operation, the supply reel of the reel stand 1 rotates in proportion to the tape drawing speed. The reel stand rotation speed detector 2 detects the rotation speed of the reel stand 1, converts the detected rotation speed of the reel stand 1 into a predetermined frequency signal, and sends it to the rotation speed comparison circuit 3.

The rotation speed comparison circuit 3 compares the frequency signal sent from the reel stand rotation speed detector 2 with the reference frequency signal 41.1) (z) in the threading mode selected above, and determines whether the tape is attached during threading. monitor the occurrence of collisions.

During threading, if the tape sticks to the drum due to dew condensation or the like, the drum is rotating at high speed and the tape is pulled out of the cassette half at a higher speed than normal. Therefore, when a tape sticking accident occurs, the rotational speed of the reel stand 1, that is, the frequency signal output from the reel stand rotational speed detector 2 becomes the reference frequency signal 41, 1 Hz.
will be a larger value.

The rotation speed comparison circuit 3 sends a sticking detection signal to the system controller 4 when the frequency signal output from the reel stand rotation speed detector 2 becomes larger than the reference frequency signal.

When the system controller I/Roller 4 receives a sticking detection signal, it sends a brake start signal to the reel stand brake drive circuit 5, activates the brake mechanism 6, applies the brakes to the reel stand 1, and stops the tape from being drawn out. At the same time, the drum servo circuit 7 is controlled to stop the drum motor 9.

Therefore, as soon as a tape sticking accident occurs, the tape is stopped being pulled out instantly, so that the tape does not get caught up in the drum as in the conventional case.

When the threading operation is completed without any tape sticking, the operation of the circuit shifts to the playback operation state instructed by the operation key, and the tape is played back. During this playback operation, the system controller 4 sends a play mode signal as a tape running mode signal to the rotation speed comparison circuit 3, and the rotation speed comparison circuit 3 selects 2.71 Hz corresponding to the play mode as a reference frequency signal. From now on, this reference frequency signal of 2.71Hz
is compared with the frequency signal output from the reel stand rotation speed detector 2, and a tape sticking accident during the play mode is detected in the same way as in the case of threading.

Similarly, when switched to the 16x speed mode, the reference frequency signal is 28.6
Hz is selected, and a tape sticking accident is detected using the optimum reference frequency signal according to the tape running mode at that time.

〔Effect of the invention〕

As is clear from the above, according to the present invention, tape sticking accidents are detected by comparing the reference rotation speed and the reel stand rotation speed, which is difficult to do with conventional dew condensation sensors. It is now also possible to detect sticking accidents due to dew condensation on the tape side, which has the excellent effect of quickly and reliably detecting all tape sticking accidents regardless of where the condensation occurs.

Furthermore, since the reference rotational speed, which is the standard for detecting tape sticking accidents, is changed depending on the tape running mode, an excellent effect is achieved in that tape sticking accidents can be automatically detected in all tape running modes.

[Brief explanation of drawings]

The drawing is a block diagram of one embodiment of the invention. 1... Reel stand, 2... Reel stand rotation speed detector, 3
... Rotation speed comparison circuit, 4... System controller, 5... Reel stand brake drive circuit, 6... Brake mechanism, 7... Drum servo circuit, 8... Motor drive circuit, 9... ...Drum motor. Patent applicant Pioneer Corporation■

Claims (1)

[Scope of Claims] 1. Reel stand rotation speed detection means for detecting the rotation speed of the reel stand; and providing the reel stand rotation speed detected by the reel stand rotation speed detection means and a preset normal tape feeding speed. and rotation speed comparison means for comparing the rotation speed with a reference rotation speed and detecting a tape sticking accident when the reel base rotation speed exceeds the reference rotation speed, and detecting a tape sticking accident by the rotation speed comparison means. A rotary head type magnetic recording/reproducing device characterized in that a brake is applied to a reel stand and a drum motor is stopped when the drum motor is stopped. 2. The rotary head type magnetic recording and reproducing apparatus according to claim 1, wherein the reference rotation speed set in the rotation speed comparison means is changed depending on the tape running mode.