JPH0437346Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a zero-track position detection device for a recording/reproducing device such as a floppy disk drive.

[Prior Art] A sensor in which a light-emitting element and a light-receiving element are opposed to each other via a parallel slit, and the object blocks the optical path of the slit to detect a predetermined position of the object has conventionally been developed using a stepping motor. It is well known that it is used for controlling the position of a moving object using.
Hereinafter, a conventional example in which such a sensor is used to detect zero track position in a magnetic disk drive device will be explained with reference to FIGS. 3 to 5.

In FIG. 3, reference numeral 3 denotes a synthetic resin carriage on which a head 4 is mounted, and a follower pin 5 is fixed to the upper right side of the carriage 3 in the figure. The carriage 3 is slidable vertically in the figure along a pair of guide shafts 7 fixed to a metal chassis 6 made of aluminum die-casting, etc., and the follower pin 5 is connected to a stepping motor 8.
The carriage 3 is moved in the radial direction of a magnetic disk (not shown) as the screw shaft 9 rotates. 10 is a detection body fixed to the chassis 6, and a sensor consisting of a light emitting element 12a and a light receiving element 12b is built into the detection body 10 via a groove 11 formed in the center of the detection body 10. . Furthermore, a hook-shaped detected portion 13 is protruded from the rear end of the carriage 3.
can move in and out of the groove 11 by moving the carriage 3.

The relative position of the sensor 12 and the detected part 13 is as follows:
When the head 4 is located on the zero track on the magnetic disk (the position indicated by the line A-A in the figure), in this position the detected part 13 of the carriage 3
The sensor 12 is set to operate by entering the concave groove 11 and blocking light from the light emitting element 12a to the light receiving element 12b.

However, due to changes in ambient temperature, the relative positions of the carriage 3 and the chassis 6, which are made of different materials, may change. It is designed to prevent zero track signals from being generated at incorrect track positions. That is, in order to generate the zero track signal, the sensor 12 must operate and the pulse signal for driving the stepping motor 8 obtained from the stepping motor control circuit must be in a predetermined state, for example, consisting of A phase and B phase. It is required that both two-phase pulse signals be in a high level state.

This will be explained below with reference to FIGS. 4 and 5. FIG. 4 is a time chart showing the relationship between the stepping motor drive pulse signal, step signal, and head position, and _S1 in the figure is from zero track to zero track. Step signal to 1 track, S ₂ is 1
A step signal from track to two tracks, _S3 is a step signal from two tracks to three tracks. As is clear from the figure, the A phase of the pulse signal,
The B phase is 90 degrees out of phase, and these A phases,
The B-phase pulse width and the track width on which the head is located are set constant. Also, when the A-phase and B-phase pulse signals are at high level, they are expressed as A and B, and when they are at low level, they are expressed as .
The relationship between the level states of the phase and B phase pulse signals is as shown in Figure 5, where A and B are output on 0 track, 2 track...2n track (n is an integer),
1 track, 3 tracks, ...(2n+1) tracks are output. Also, from these figures 4 and 5, we compare the step signal command, for example, the signal _S1 from zero track to 1 track, and the time it takes for the head 4 to actually move to the position corresponding to that command, for example, the 1 track position. It can be seen that the head 4 is moved somewhat backward.

Therefore, the detected part 13, which is adjusted to the zero track position at room temperature, expands to the position 13' shown by the broken line in FIG. In other words, when transferring from track n to track 2 to track 1 to track 0, for example, even if the sensor 12 operates when the head 4 is at the 1 track position, the level state of the pulse signal at this time will not affect the head. Since it is in a state where it should move from track 2 to track 1 (state between steps S ₁ and S ₂ in Fig. 4),
Both do not output high level states A and B, and no zero track signal is generated. Then, a step signal for moving the head 4 from the 1 track to the 0 track is supplied, and in response to this step signal, both the level states of the pulse signals become high levels A and B.
When the head 4 is moved to the zero track position, a zero track signal is generated by the above-mentioned operating signal of the sensor 12 and the A and B pulses. In this way, the detected part 13 of the carriage 3 due to changes in ambient temperature.
Even if there is a change in the relative position of the head 4 with the sensor 12, a zero track signal is reliably generated when the head 4 is at the zero track position. It can be transferred from location to location.

[Problem that the invention attempts to solve]

However, in the conventional example described above, 0
Move the head 4 in the track position from the outside of the magnetic disk to the inside, that is, 0 track, 1 track,
When moving from track 2 to track n, there were drawbacks as described below.

That is, the detected portion 13 extends to the position 13' shown by the broken line in FIG. 3 in accordance with the temperature change, and in this state the head 4, which is at the 0 track position, is transferred to the 1 track, 2 track, . . . n track. In this case, since the detected part 13 is extended, the sensor 12 continues to operate until, for example, the step signal _S1 is supplied and the head 4 is located at one track. The timing at which this step signal _S1 and the head 4 are actually moved to the 1 track position is, as mentioned above, because the head 4 is somewhat behind the step signal. until the next status signal _S2 is supplied.
Head 4 is in the one track position and sensor 12 continues to operate. When the step signal _S2 is supplied in this way, the level states of the pulse signals are both high levels A and B (see FIGS. 4 and 5), so the A and B pulses and the sensor 12 There was a problem in that a zero track signal was generated even though the head 4 was at the one track position due to the operation signal. When such an erroneous zero track signal is generated, the head 4 is subsequently moved from the inside to the outside using the position where this signal is generated as a reference.

Therefore, the purpose of the present invention is that even if the relative position of the detected part of the carriage and the sensor that detects it shifts due to changes in ambient temperature,
To provide a zero track position detecting device which does not generate an erroneous zero track signal and can always carry out correct head transfer.

[Means for solving problems]

In order to achieve the above object, the present invention provides a carriage equipped with a head and capable of transporting the magnetic disk in the radial direction, a sensor capable of detecting a detected portion of the carriage, and a stepper for transporting the carriage. a motor, the sensor detects the detected part and operates, and a zero track signal is generated when a pulse signal for driving the stepping motor obtained from a control circuit of the stepping motor is in a predetermined state. The magnetic recording and reproducing apparatus detects the zero-track position of the head based on the zero-track signal, and the detecting means outputs a constant level signal according to the moving direction of the head, and the detecting means includes: switching means that is controlled on and off according to the detection result and cuts off or passes the output of the sensor, and when the head is transferred from the outside to the inside of the magnetic disk, the output of the sensor is switched on and off. when the head is transferred from the inside to the outside of the magnetic disk;
Its feature is that the output of the sensor is configured to pass through a switching means.

[Effect]

That is, according to the present invention, for example, when a direction signal that determines the moving direction of the head and a step signal for driving a stepping motor are input to the detection means, two different types of signals are output from the detection means depending on the moving direction of the head. can be output. Then, when the output from this detection means and the output from the sensor are input to a switching means, for example, an AND gate, this switching means changes the output of the sensor when the sensor is transferred from the outside to the inside of the magnetic disk. The output of the sensor can be passed through when the head is moved from the inside to the outside, so that when the head is moved from the outside to the inside it will not generate a zero track signal and the head will generates the desired zero track signal only when it is transferred from the inside to the outside.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a zero-track position detecting device according to an embodiment of the present invention, in which 1 is a D-type flip-flop, and this flip-flop 1 has a clock input terminal C, a data input terminal D, and an output terminal Q. This is a well-known device equipped with the following. Also, 2
is an AND gate, and these flip-flop 1 and AND gate 2 constitute the zero track position detection circuit of this embodiment. The zero-track position detection circuit is attached to a conventionally known stepping motor control circuit (not shown).

FIG. 2 shows a direction signal for determining the direction of movement of the head, that is, whether to move the head from the outside to the inside or from the inside to the outside with respect to the magnetic disk, and the stepping motor described above. This is a timing chart showing the relationship with signals. As shown in the figure, when step signals S ₁ , S ₂ ,...S _o are supplied to move the head from the outside to the inside of the magnetic disk, the direction signal becomes low level at the rise of the step signal. Therefore,
When the step signals S _o , . . . , S ₂ , S ₁ are supplied to move the head from the inside to the outside of the magnetic disk, the direction signal is at a high level when the step signal rises, contrary to the above. Conventionally, the direction signal and the step signal were directly input to the stepping motor control circuit, but in this embodiment, the direction signal is input to the data input terminal D of the flip-flop 1.
The step signals are input to the clock input terminals C of the flip-flop 1, respectively.

With this configuration, for example, in order to move the head at the 0 track position to the 1 track, 2 track, . . . When the flip-flop 1 inputs each of be done.

Therefore, even if the relative position between the detected part of the carriage and the sensor shifts due to a change in ambient temperature, and the head is moved from the 0 track position of the magnetic disk to the 1 track position, the sensor is still in the operating state, that is, Even when a high level signal is being output, by inputting this high level signal and the low level signal from the output terminal Q to the AND gate 2 and taking the logical product,
A low level signal can be obtained as the output signal of AND gate 2. If the output signal from this AND gate 2 is taken as the true sensor signal, then whenever the head moves from the outside to the inside of the magnetic disk, the true sensor signal will be at a low level, that is, no zero track signal will occur. Therefore, as explained in the prior art, it is possible to solve the problem that, for example, a zero track signal is generated even though the head is at the one track position.

Contrary to the above, when moving the head from the n track position to the 0 track position on the magnetic disk, the flip-flop 1 detects the level state of the direction signal at the rising edge of the step signal, that is, the high level state. In order to hold the output until the next rising edge, the output terminal Q of flip-flop 1 is
It constantly outputs Hare level signals. Therefore, input the high level signal from the output terminal Q and the operation signal from the sensor to the AND gate 2,
By taking the logical product, AND gate 2 is activated only when the sensor is activated and reaches a high level state.
outputs a high level state. And it takes
Since the output signal of AND gate 2 is supplied to the stepping motor control circuit as a true sensor signal, when moving the head from the inside to the outside of the magnetic disk, a zero-track position detection circuit shown in Figure 1 must be attached. This is the same as inputting the sensor output directly to the stepping motor control circuit without
That is, when the sensor outputs an operating signal and the pulse signal both become high level, a zero track signal is generated.

In the embodiment described above, even if the relative position between the detected part of the carriage and the sensor shifts due to changes in ambient temperature, the zero track position detection circuit shown in FIG. It is possible to cancel the sensor output when moving from the zero track side to the inside, thereby preventing the generation of an erroneous zero track signal. The zero track position detection circuit also includes a flip-flop that detects the moving direction of the head, and an AND that turns on and off the output of the sensor based on the output of the flip-flop.
It has a simple circuit configuration with the gate, and since it only needs to be attached to the stepping motor control circuit, the cost will not increase significantly.

[Effect of idea]

As explained above, according to the present invention, the output of the sensor that detects the detected part of the carriage can be canceled only when the head is transferred from the outside to the inside of the magnetic disk. Even if the relative positions of the detection section and the sensor are deviated, the head can be transferred correctly.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a zero-track position detection device according to an embodiment of the present invention, FIG. 2 is a timing chart showing the relationship between a direction signal and a stepping signal input to the circuit, and FIG. 3 is a diagram of the present invention. FIG. 4 is a plan view of the magnetic recording/reproducing apparatus to which the invention is directed, FIG. 4 is a timing chart showing the relationship between the pulse signal for driving the stepping motor provided in the magnetic recording/reproducing apparatus, the step signal, and the head position. FIG. FIG. 3 is an explanatory diagram showing the relationship between the pulse signal and the head position. 1...Flip-flop, 2...AND gate.

Claims (1)

[Scope of utility model registration request] A carriage mounted with a head and capable of transporting the magnetic disk in the radial direction, a sensor capable of detecting the detected portion of the carriage, and a stepping motor for transporting the carriage, wherein the sensor detects the detected portion. When the pulse signal for driving the stepping motor obtained from the control circuit of the stepping motor is in a predetermined state, a zero track signal is generated, and the zero track of the head is activated based on the zero track signal. In a magnetic recording/reproducing apparatus configured to detect a position, a detection means outputs a constant level signal according to the moving direction of the head, and the detection means is controlled to be turned on and off according to the detection result of the detection means. switching means for blocking or passing the output of the sensor; when the head is transferred from the outside to the inside of the magnetic disk, the output of the sensor is cut off by the switching means; 1. A zero-track position detecting device for a magnetic recording/reproducing device, characterized in that the output of the sensor is passed through the switching means when the magnetic recording/reproducing device is transferred to the outside.