JP2549042B2 - Method for detecting the dew condensation state of a drum in a rotary magnetic head type magnetic recording / reproducing apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the dew condensation state of a drum in a rotary magnetic head type magnetic recording / reproducing apparatus such as an R-DAT.

[0002]

2. Description of the Related Art In a rotary magnetic head type magnetic recording / reproducing apparatus such as a VTR or an R-DAT, when the peripheral surface of a drum structure composed of a rotary drum and a fixed drum is condensed, the vehicle travels in a state of sliding contact with the peripheral surface of the drum. Since the magnetic tape adheres to the peripheral surface of the drum due to the dew and damages the magnetic tape, in the conventional rotary magnetic head type magnetic recording / reproducing apparatus, for example, a drum structure including a rotary drum and a fixed drum is used. The temperature of the head structure is heated with electric heat so that it is higher than the room temperature of the place where it is used, or with the dew detection sensor (dew sensor),
When a dew condensation sensor detects a dew condensation state, the drive motor of the rotary drum is stopped.

[0003]

However, among the above-mentioned conventional techniques, the means for constantly heating the drum structure to a temperature higher than room temperature consumes a large amount of power for heating the drum structure. It cannot be used in a portable small rotary magnetic head type magnetic recording / reproducing apparatus in which electric power is a big problem. Further, in the rotary magnetic head type magnetic recording / reproducing apparatus configured to detect the dew condensation state by using the dew detection sensor, the dew state is not detected because the dew detection sensor takes some time. The magnetic tape may be damaged by the rotation of the rotary drum in a state where the magnetic tape is attached to the peripheral surface of the drum structure before being detected. Therefore, there has been a demand for the appearance of a method for detecting the dew condensation state of a drum in a rotary magnetic head type magnetic recording / reproducing apparatus capable of quickly and surely determining the dew condensation state.

[0004]

SUMMARY OF THE INVENTION The present invention is a means for half-loading a magnetic tape onto a drum structure so that a magnetic tape that is not running is brought into light contact with the surfaces of a stationary rotary drum and a stationary drum, and a rotary drum. A means for supplying driving power to a motor for driving the motor for a predetermined short time, and a counting means for counting the number of rotation pulses generated corresponding to the rotation of the rotating drum within the predetermined time. , Condensation of the drum in the rotary magnetic head type magnetic recording / reproducing apparatus, which comprises means for comparing the number of rotation pulses counted by the counting means with a predetermined value to determine the presence or absence of condensation on the rotating drum. State detection method.

[0005]

The magnetic tape is half-loaded on the drum structure, and the magnetic tape that is not running is brought into light contact with the surfaces of the stationary rotating drum and the stationary drum. Driving electric power is supplied to a motor for driving the rotating drum for a predetermined short time to rotate the rotating drum. The number of pulses generated during rotation of the rotating drum is counted within a predetermined time, and when the number is smaller than a predetermined value, it is determined that the drum is condensed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The specific contents of the method for detecting the dew condensation state of the drum in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram of a part of a rotary magnetic head type magnetic recording / reproducing apparatus configured by applying the method for detecting the dew condensation state of a drum in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention, and FIG. 2 is a rotation diagram of the present invention. 6 is a flowchart for explaining a method of detecting a dew condensation state of a drum in a magnetic head type magnetic recording / reproducing apparatus.
In FIG. 1, 1 is a fixed drum, 2 is a rotating drum, and the fixed drum 1 and the rotating drum 2 constitute a drum structure. Reference numerals 3 and 4 are tilt guides, 5 and 6 are vertical guide rollers, and T is a magnetic tape. The tilt guides 3 and 4 and the vertical guide rollers 5 and 6 are predetermined by a loading mechanism driven by a loading motor 14. Of the magnetic tape T
Is wound around the peripheral surface of the drum structure including the fixed drum 1 and the rotating drum 2.

In the rotary magnetic head type magnetic recording / reproducing apparatus such as the R-DAT shown in FIG. 1, the loading operation of the magnetic tape T on the peripheral surface of the drum structure is stopped. And fixed drum 1
And a peripheral surface of the fixed drum 1 in a fixed state with a half-loading operation in which the magnetic tape T is lightly contacted with the peripheral surface of In addition, two types of loading operations, that is, a loading operation for bringing the magnetic tape T into a sure contact state, are performed. In the method for detecting the dew condensation state of the drum in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention, the loading state of the magnetic tape T on the peripheral surface of the drum structure including the rotating drum 2 and the fixed drum is stopped. The magnetic tape T is lightly contacted with the peripheral surfaces of the rotating drum 2 and the fixed drum 1 in a half-loading state.

In FIG. 1, reference numeral 8 denotes an operating portion, which is used to make inputs for setting various operation modes of the rotary magnetic head type magnetic recording / reproducing apparatus. Reference numeral 9 denotes a control unit including, for example, a microprocessor. In the control unit 9, the operation of each component of the rotary magnetic head type magnetic recording / reproducing apparatus is performed based on the information input from the operation unit 8. To control. Reference numeral 7 denotes a dew detection sensor. The dew detection sensor 7 is installed in the vicinity of the drum structure, and controls the information under conditions of temperature and humidity such that dew condensation occurs on the peripheral surface of the drum structure. Give to part 9. As a result, the control unit 9 drives the rotary drum drive motor M.
(Drum motor M) is prevented from rotating to prevent the magnetic tape T from being damaged.

If the dew detection sensor 7 is used to detect the dew condensation state on the drum structure, it takes some time for the dew detection sensor to detect the dew condensation. As described above, when the rotating drum rotates while the magnetic tape is stuck to the peripheral surface of the drum structure before the dew condensation state is detected, the magnetic tape is damaged. Is. Therefore, in the method of detecting the dew condensation state of the drum in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention, the dew detection sensor 7 is used when the dew state is not detected by the dew detection sensor 7. The detection operation of the presence or absence of dew condensation on the drum structure is performed by a method not used. When detecting the presence or absence of dew condensation on the drum structure by the method for detecting the dew condensation state on the drum structure in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention, first, the detection of the presence or absence of dew condensation is started from the operation unit 8. Information for this is input to the control unit 9.

Information for starting the detection of the presence or absence of dew condensation is supplied from the operation unit 8 to the control unit 9 which operates the loading motor drive circuit 13 to operate the loading motor 1.
When the magnetic tape T is lightly contacted with the peripheral surfaces of the rotary drum 2 and the fixed drum 1 which are stopped by the operation of the loading mechanism 18 by rotating 4, That is, the magnetic tape T is put into a half-loading operation state on the peripheral surface of the drum structure. Next, the control unit 9 checks whether the dew detection sensor 7 outputs an output indicating the dew condensation state of the drum as in step (1) of FIG. 2, that is, whether the dew condensation state of the drum is detected. , Dew detection sensor 7
When the dew condensation state is detected, that is, when step (1) is YES, the process proceeds to step (12) to stop the operation of the magnetic recording / reproducing apparatus. Further, in step (1), it is checked whether the dew detection sensor 7 detects the dew condensation state, and when the dew detection sensor 7 does not detect the dew condensation state, that is, when the step (1) is NO. Advances to step (2) to activate the drum motor M for driving and rotating the rotary drum 2.

When the drum motor M rotates, a signal generator (not shown) provided in the drum motor M makes one rotation of the drum motor M one cycle and a pulse signal (duty cycle: 50%). DFF pulse signal ... A signal also called a drum flip-flop signal or a switching pulse signal) is output. The above-described drum motor M is activated in step (2) of FIG. 2 and then waits for a predetermined time in step (3), and the supply of drive power to the drum motor M is cut off in step (4). The above-described operation in steps (2) to (4) of FIG. 2 is performed by the control unit 9 of FIG. 1 by turning on the switch 11 for a predetermined short time, and from the power supply 10 to the motor drive circuit. This corresponds to an operation in which the motor driving circuit 12 drives and rotates the drum motor M for a short time by supplying electric power for operation to 12 for a predetermined short time.

As described above, even if the driving power is supplied to the drum motor M for a predetermined time and then the supplied power is cut off, the above-mentioned signal generation is performed as long as the drum motor M continues to rotate due to inertia. The device continues to output the DFF pulse signal, but the state of rotation of the drum motor M due to the inertia described above is such that dew condensation occurs on the peripheral surface of the drum structure and that on the peripheral surface of the drum structure. It will be completely different when it is not. That is, if there is condensation on the peripheral surface of the drum structure,
The magnetic tape T that is loaded in a state where the magnetic tape T is lightly contacted with the peripheral surface of the drum structure that includes the rotating drum 2 and the fixed drum 1, that is, the magnetic tape T that is in the half-loading state is the drum structure. Due to dew condensation on the peripheral surface of the drum structure, the drum motor M is heavily bonded to the peripheral surface of the drum structure. Therefore, the rotation of the drum motor M due to inertia is immediately stopped. However, when dew condensation does not occur on the peripheral surface of the drum structure, the magnetic tape T is left in a state of being lightly contacted with the peripheral surfaces of the rotary drum 2 and the fixed drum 1 and the magnetic tape T remains loaded. This is because the drum motor M can continue to rotate due to inertia in a state where it is in slight contact with the magnetic tape T.

Then, in step (4) of FIG. 2, the supply of drive power to the drum motor M is stopped, and then in step (5), the counter 15 in FIG. 1 is cleared, and then in step (6). For a period of one cycle, and one cycle of the drum motor M generated by a signal generator (not shown) provided in the drum motor M by the counter 15 is set as one cycle, and the duty cycle is 50%. When the pulse signal (DFF pulse signal) is counted, depending on the state of the count value of the counter 15, the peripheral surface of the drum structure is in a dew condensation state or the peripheral surface of the drum structure. You can see if there is no condensation on the surface.

As a result of checking whether or not there is a DFF pulse signal in step (7) in FIG. 2, if there is no DFF pulse signal, that is, if step (7) is NO, proceed to step (9). Also, in step (7), DFF
As a result of checking whether or not there is a pulse signal, if there is a DFF pulse signal, that is, if step (7) is YES, the process proceeds to step (8). Then, in step (8), the count value of the counter 15 in FIG. 1 is incremented by 1, and then the process proceeds to step (9). In step (9), it is checked whether or not a fixed time has passed, and if the fixed time has not passed, the process returns to step (7), and if the fixed time has passed, step (10) Proceed to. In step (10), it is checked whether the count value of the counter 15 in FIG. 1 is 2 or more. If the count value of the counter 15 in step (10) has not reached 2, the process proceeds to step (12). When the operation of the magnetic recording / reproducing apparatus is stopped and the count value of the counter 15 in step (10) is 2 or more, the process proceeds to step (11), and the magnetic recording / reproducing apparatus is made to proceed the normal operation. It

Step (5) to step of FIG. 2 described above
The operations (11) and (12) are performed by a signal generator (not shown) provided in the drum motor M after the counter 15 shown in FIG. 1 is cleared by the control of the controller 9. The DFF pulse signal generated over a predetermined time is counted by the counter 15 described above, the count value of the counter 15 is supplied to the comparator 17, and the comparator 17 is set in the register 16. If the count value in the counter 15 is smaller than the numeric value 2 set in the numerical register 16 as compared with the numeric value 2, the control unit 9 determines that dew condensation has occurred on the peripheral surface of the drum structure. Then, the operation of the magnetic recording / reproducing apparatus is stopped, and conversely to the above case, if the count value in the counter 15 is larger than the numerical value 2 set in the register 16, the controller 9 causes the drum 9 to rotate. Condensation forms on the peripheral surface of the structure Controls to continue the operation of the magnetic recording and reproducing apparatus determines that no. In the above-described embodiment, the numerical value set in the numerical register 16 is 2. However, the numerical value set in the numerical register 16 is not limited to 2, and may be changed depending on the characteristics of the drum motor M used. The predetermined numerical value is set in the numeral value 16.

[0016]

As is apparent from the above detailed description, the method of detecting the dew condensation state of the drum in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention is such that the magnetic tape is half-loaded on the drum structure and is run. With the magnetic tape that is not in contact with the surface of the stationary drum and the stationary drum in light contact, the motor that drives the rotating drum is supplied with driving power for a short period of time to rotate the rotating drum. , The number of pulses generated during rotation of the rotating drum is counted within a predetermined time, and when the number is smaller than the predetermined value, it is determined that the drum has dew condensation and it is rotated. Since the operation of the magnetic head type magnetic recording / reproducing apparatus can be stopped, the present invention can satisfactorily solve the problem in the above-mentioned conventional technique. Kill.

[Brief description of drawings]

FIG. 1 is a block diagram of a part of a rotary magnetic head type magnetic recording / reproducing apparatus configured by applying a method for detecting a dew condensation state of a drum in the rotary magnetic head type magnetic recording / reproducing apparatus.

FIG. 2 is a flow chart for explaining a method of detecting the dew condensation state of the drum in the rotary magnetic head type magnetic recording / reproducing apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed drum, 2 ... Rotating drum, 3, 4 ... Inclined guide, 5, 6 ... Vertical guide roller, 7 ... Dew detection sensor, 8
... operation part, 9 ... control part, 10 ... power supply, 11 ... switch,
12 ... Motor drive circuit, 13 ... Loading motor drive circuit, 14 ... Loading motor, 15 ... Counter, 1
6 ... Number register, 17 ... Comparator, 18 ... Loading mechanism,
T ... magnetic tape, M ... rotary drum drive motor M (drum motor M),

Claims (1)

(57) [Claims] 1. A means for half-loading a magnetic tape on a drum structure so as to lightly contact a surface of a stationary drum with a stationary magnetic tape, and a motor for driving the rotating drum. , A means for supplying driving power for a predetermined short time, a counting means for counting the number of rotation pulses generated in correspondence with the rotation of the rotary drum within a predetermined time, and a counting means for counting by the above-mentioned counting means A method for detecting the dew condensation state of a drum in a rotary magnetic head type magnetic recording / reproducing apparatus, which comprises a means for comparing the number of generated rotation pulses with a predetermined numerical value to determine the presence or absence of dew condensation on the rotating drum.