JPS6331862B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a needle tip cleaning device in a capacitance change detection type playback device, and in particular to a device for cleaning the tip of a needle in a capacitance change detection type playback device. The present invention relates to a device for cleaning the tip of a playback needle of a device that reads and plays back recorded signals by detecting changes.

Conventionally, an information signal is recorded on a disk-shaped recording medium (disk) as a change in mechanical shape, and the recorded information signal is transferred to an electrostatic capacitor formed between the disk and the electrode of a reproducing needle. A capacitance change detection type reproducing device is known that detects a change in capacitance, reads and reproduces the data. In such a playback device, the playback needle slides and scans over the disk to play back recorded information signals, so if foreign matter on the disk adheres to the electrode surface of the playback needle, its surroundings, or the sliding contact surface, the playback needle will move. Good contact between the disc and the disc cannot be maintained, resulting in a loss of playback signal.

Therefore, it is necessary to clean the regenerated needle tip in order to remove dust and the like attached to the tip.
Therefore, conventionally, the stylus tip has been rubbed with a brush at the start of disc playback or at the end of disc playback, using one of two methods as described below. In other words, the first conventional cleaning method detects when the carriage that transports the regenerated needle in the radial direction of the disk comes to the rest position (standby position), and then applies needle pressure to remove the tip of the regenerated needle. In this method, the needle is lowered onto the brush and the brush is rotated at the same time to clean the tip of the needle.

In addition, the second conventional cleaning method detects that the carriage is moving on a fixed brush and applies needle pressure to slide the tip of the regenerated needle on the brush and remove the tip of the needle. This is a method of cleaning.

Problems to be Solved by the Invention However, the above two conventional methods are difficult to solve because there are two types of dust that adhere to the electrode surface and its surroundings, and one that adheres to the sliding contact surface.
It was difficult to remove different types of trash at the same time. Also, in order to increase the degree of contact between the brush and the needle tip, increasing the rotation speed of the rotating brush or increasing the distance the needle tip moves on the fixed brush will prevent the regenerated needle from jumping on the brush, resulting in poor results. I can't. Also, if you increase the stylus pressure to prevent jumps,
The tip of the needle got stuck inside the brush, and there was a risk of damaging the recycled needle.

Therefore, the present invention vibrates a regenerated needle on a brush that performs rotational or linear motion on the brush surface, thereby removing dust adhering to the electrode surface and its surroundings and dust adhering to the sliding surface of the regenerating needle, respectively. It is an object of the present invention to provide a needle tip cleaning device that has been removed at the same time.

Means for Solving the Problems The present invention provides a brush that is made of bristles and has a cross section that can be considered to be flat compared to the area of the sliding surface of a regenerated needle, and that performs rotational or linear motion. During this period, the needle tip of the regeneration needle is brought into contact with the brush, and a vibration signal is supplied to the control coil for moving the regeneration needle on the track during regeneration on a plane approximately parallel to the brush surface. The above-mentioned problem has been solved by configuring the device to vibrate in a direction substantially perpendicular to the direction of motion, and one embodiment thereof will be described below with reference to the drawings.

Embodiment FIG. 1 is a plan view showing a schematic configuration of an embodiment of the apparatus of the present invention, FIGS. 2 and 3 are a plan view and a side view of an embodiment of the main part of FIG. 1, respectively, and FIG. 4 1 shows a sectional view of an example of a main part of a reproducing device to which the device of the present invention can be applied. In each figure, the same components are given the same reference numerals. In FIG. 1, the disk 10 is lowered and placed on the turntable 11 while its central portion is supported by a support body consisting of an elevator 25 and a lifter 26, which will be described later. disk 10
Before the start of playback or after the end of playback, the pick-up housing 12 is in the rest position 12a. The pick-up housing 12 includes a pick-up device including a cantilever 14 having a regenerating needle 13 at its tip, a resonator (not shown), etc.
installed on.

The carriage 15 has rollers 16a, 1 on both sides thereof.
6b and 16c are provided. Roller 16a rolls on rail 17a, and rollers 16b and 16
By rolling on the rails 17b,
The carriage 15 moves in the X or Y direction of the arrow. A wire 19 is stretched between the pulleys 18a and 18b. The wire 19 is attached to the carriage 15, and the pulley 18a is rotated by a motor 20. As a result, when the motor 20 rotates, the pulley 18a rotates, and the wire 19 is transferred in the direction of the arrow X or Y depending on the direction of rotation, and thereby the carriage 15 is also transferred in the direction of the arrow X or Y.

A cylindrical rubber pipe 22 made of rubber is attached and fixed to one end of the rod 21, and the other end of the rod 21 is connected to a first
In the figure, it is locked to the pin 24 of the arm 36 shown in FIG. 5, which is moved leftward or rightward. The outer peripheral surface of the rubber pipe 22 is pressed against the side surface 23a of the rotating body 23 by the spring force of a coil spring (not shown). As shown in FIGS. 2 and 3, a brush 29 made of, for example, pig hair is provided on the upper part of the rotating body 23, and has a cross section that can be regarded as flat compared to the area of the sliding surface of the regenerating needle 13. It is being When the carriage 15 is in the rest position, the regeneration needle 13 is located above the rotating body 23, as shown in FIG.

The above-mentioned rotating body 23 is moved up by the elevator 25,
The rod 21 is configured to be rotated in the direction of arrow B only when it is moved in the direction of arrow A. Next, the raising and lowering operation of the elevator 25 and the movement of the rod 21 will be explained. In FIG. 4, when the operator of the playback device operates a load switch (not shown) after turning on the power, the playback device enters a state in which the disk storage case 32 containing the disk 10 can be inserted, and the elevator 25 and The support body consisting of the lifter 26 rises to the spatial position shown by the two-dot chain line in the figure.

Here, in FIGS. 1 and 4, the lifter 26 is U
The ring-shaped bottom surface of the elevator 25 is placed on the top surface of the ring-shaped bottom surface. The inner diameter of the ring-shaped elevator 25 is slightly larger than the outer diameter of a center spindle 28 attached to the tip of a rotating shaft 27 of a motor 33 that rotates the turntable 11. The outer peripheral tapered surface of the center spindle 28 has a diameter that fits into the inner diameter of the center hole of the disk 10. The upper end of the elevator 25 is a lifter 26
By raising and lowering, the turntable 11 is raised and lowered from a position above the turntable 11 (standby position) to a position substantially equal to the rotation surface of the turntable 11 (playback position).

The lifter 26 is configured to be movable in the vertical direction by an elevating mechanism 35 shown in FIG. 5, and an arm 36 having a pin 24 planted at its tip moves in conjunction with the elevating and lowering of the lifter 26 as shown by the arrow in FIG. Move in direction D. Reference numeral 37 in FIG. 4 is a wire, one end of which is fixed to the lifter 26, and is led from the lifter 26 through a roller 38 and a roller 40 provided on the lower surface of the lifter elevating lever 39, respectively, to reel 41.
The other end is fixed to. The reel 41 is configured to transmit the rotational force of a lift motor (not shown), and the wire 37 is wound onto or unwound onto the reel 41 depending on the direction of rotation of the lift motor, thereby causing the elevator to move. 25 and lifter 26 are raised or lowered.

As mentioned above, when the playback device is in the state where it can be inserted into the disk storage case 32, the elevator 2
5 and the lifter 26 are in the spatial position shown by the two-dot chain line in FIG. In this state, when the disk storage case 32 is inserted and pulled out, the lid of the disk storage case 32 and the disk 10 are moored inside the playback device, only the case body is pulled out of the playback device, and the center of the disk 10 is moored. Part is elevator 2
Supported by 5. When the attachment of the disk 10 is determined by a micro switch or the like provided in the playback device, the lift motor is rotated in a predetermined direction, and the reel 41 is rotated in the direction in which the wire 37 is fed out. As a result, the elevator 25 supports the disk 10 and begins to descend together with the lifter 26 from the standby position shown by the two-dot chain line in FIG.
0 is placed on the turntable 11, it is further lowered and reaches the position shown by the solid line in the figure.

When the elevator 25 and lifter 26 descend, the rod 21 and rubber pipe 22 shown in FIGS. 1 to 3 are moved in the opposite direction to arrow A. Here, since the outer circumferential side of the rubber pipe 22 is pressed against the outer circumferential side of the rotating body 23, the rotating body 23 attempts to rotate clockwise around the fulcrum 30 due to frictional force, but the clutch shown in FIG. The arm 31 prevents its rotation.

When the start switch is operated in this state, the carriage 15 and pick-up housing 12 are moved from the rest position 12a in the direction of arrow X in FIG. In FIG. 1, reference numeral 12b indicates the position of the pickup housing 12 and the carriage 15 at a certain playback point. 6th
The figure shows the state of sliding between the tip of the regenerating needle 13 and the disk 10. In the figure, the information signal is recorded on the disk 10 by repeating the pits 42 and the flat surface 43, and the track width TW is the same as the track pitch TP.
A first tracking signal _fp1 recording track and a second tracking signal _fp2 recording track are formed at intermediate positions between two adjacent tracks. In FIG. 6, the tracking signal _fp1 is recorded by repeating the pit 44 and the flat part 43, and the tracking signal _fp2 is recorded by repeating the pit 45 and the flat part 43.

The regenerating needle 13 has an electrode 13b fixed by vapor deposition on the rear end surface of the regenerating needle main body 13a.
track width on the surface of the disk 10 rotating at
A sliding surface 13c having a width larger than TW slides. As a result, the disk 1 with electrode function
The capacitance formed between 0 and the electrode 13b is
Since it changes in response to the intermittent pits 42, 44, 45, this change is converted into an electrical signal by a circuit within the pickup housing 12, and read and reproduced by a known method.

Next, when the reproduction of the disk 10 is completed or when the operator operates the unload switch, the carriage 15 is moved in the direction of arrow Y in FIG. 1 and reaches the rest position 12a. The arrival of the carriage 15 at this rest position 12a is detected by, for example, a microswitch, and the detection output causes the lift motor to rotate in the opposite direction, and the wire 37 shown in FIG. 4 is wound onto the reel 41. As a result, the elevator 25 rises again to the position shown by the two-dot chain line in FIG. 4 while supporting the central portion of the disk 10.

During the rising period of the elevator 25 and the lifter 26, the rod 21 and the rubber pipe 22 shown in FIGS. Due to the frictional force between them, the rotating body 23 and the brush 2 are moved in the direction of arrow A.
9 rotates in the direction of arrow B (counterclockwise). On the other hand, when the pick-up housing 12 reaches the rest position 12a, stylus pressure is automatically applied to the regeneration needle 13.
As a result, the tip of the regenerating needle 13 is brought into contact with the brush 29. Therefore, the dust attached to the tip of the regenerated needle 13 is removed by the rotation of the brush 29 as described above.

However, this alone causes the above-mentioned problems. Therefore, in this embodiment, the regeneration needle 13 is vibrated in the direction shown by arrow C in FIG. 1, and the details thereof will be explained next.

FIG. 7 shows a circuit diagram of an embodiment of the main part of the device of the present invention. In the same figure, the input terminal 46 has a polarity corresponding to the tracking deviation direction obtained by differentially amplifying each re-biopsy wave signal of the tracking signals fp ₁ and fp ₂ .
A tracking error signal having a level corresponding to the amount of tracking deviation is input, and is applied to the inverting input terminal of the operational amplifier 47 via the resistor _R1 . Normally, the tracking error signal is extracted from the operational amplifier 47 and applied to the bases of the NPN transistor Q ₂ and the PNP transistor Q ₃ via the resistor R ₇ . On the other hand, input terminals 48, 4
9 are both connected to a pulse signal output port of a microcomputer that performs mechanical control of the playback device, and during normal playback of the disc 10, the input terminal 48 is held at a voltage of +6V, the input terminal 49 is held at a voltage of 0V, The emitter output of NPN transistor _Q1 , with both input signals applied to its base, is fixed at +5V.

The base of the transistor Q ₁ is connected to the base bias resistors R ₅ and R ₆ , and its emitter is connected to the -12V power supply voltage input terminal via the resistor R ₄ , and the capacitor C ₁ , capacitor C ₂ , and The non-inverting input terminal of the operational amplifier 47 is connected to the non-inverting input terminal of the operational amplifier ₄₇ via a parallel circuit consisting of a resistor R 3 in series, and this non-inverting input terminal is grounded via a resistor R ₂ . transistors Q ₂ to which the output signals of the operational amplifier 47 are commonly applied to their respective bases;
Each collector of Q ₃ is connected to the base of PNP transistor Q ₅ , the base of NPN transistor Q ₄ ,
Furthermore, each emitter of transistors Q ₂ and Q ₃ and Q ₄ ,
The collectors of _Q5 are commonly connected to one end of resistor _R9 and a common connection point of tracking control coils _L1 and _L4 , which will be described later. Further, the connection point between the resistor _R1 and the inverting input terminal of the operational amplifier 47 is connected to the other end of the resistor _R9 , and the
It is grounded through _R10 and _R11 in series.
Furthermore, the emitters of transistors Q ₂ and Q ₃ are each commonly grounded via a resistor R ₈ , and the connection point of resistors R ₁₀ and R ₁₁ is connected to a tracking control coil L ₂ ,
Connected to L ₃ common connection point.

Tracking control coils L ₁ and L ₂ , L ₃ and L ₄ are connected, respectively, and these coils L _1
.about.L4 is disposed in the pick-up housing 12 shown in FIG. 1 together with the regeneration needle 13 and the like in the configuration shown in FIG. 8. In FIG. 8, the cantilever 14
A regeneration needle 13 is fixed to the tip of the needle, and an elastic support member (damper) 55 is fitted to the rear end, and a permanent magnet 56 is fixed to the rear end. Regeneration needle 13,
The cartridge consisting of the cantilever 14 and the permanent magnet 56 is assembled into the case by pressing both arms of the damper 55 into the notches 57a and 57b of the case.

The coil assembly 58 is fixed to the housing and includes tracking control coils L ₁ , L ₂ , L ₃ , L ₄
and a jitter correction coil _L5 are attached.
The coils L ₁ to _{L 4} are arranged with their axes perpendicular to the magnetization direction of the permanent magnet 56 . The coil assembly 58 is also provided with a needle pressure applying coil (not shown).

The above configuration was previously proposed by the present applicant, but in this embodiment, the tracking control circuit is provided with an oscillation pulse for only a predetermined period from the collector of the NPN transistor _Q7 shown in FIG.
This is applied to the base of _Q1 .
That is, in FIG. 7, the input terminal 50 receives a rest position detection signal obtained by detecting that the pick-up housing 12 etc. has come to the rest position 12a, and the input terminal 51 receives a stylus pressure application signal. come in,
Resistors R ₁₂ , R ₁₃ , R ₁₄ , diodes D ₁ , D ₂ and
The signal is applied to the oscillation control terminal (reset terminal) of the astable multivibrator IC 53 via a NOR circuit 52 consisting of an NPN transistor _Q6 . For example, the IC 53 oscillates when the terminal 53c is at a high level, and applies an oscillation pulse with a repetition frequency of 200 Hz from the output terminal 53b to the pulse output circuit 54 consisting of the resistor R ₁₇ , the capacitor C ₄ and the transistor Q ₇ , and the terminal 53 b When the level is low, the oscillation operation is stopped. Resistors R ₁₅ , R ₁₆ and capacitor C ₃ are connected to IC 53 to determine the oscillation frequency. The collector of transistor _Q7 is connected to the base of transistor _Q1 .

Next, to explain the operation of the circuit shown in FIG. 7, during normal regeneration, the emitter of transistor _Q1 is fixed at +5V as described above, and a low level stylus pressure application signal is input to input terminal 51. ,
Moreover, the rest position detection signal does not enter the input terminal 50 and is at a high level. Therefore, NOR
The output of the circuit 52 becomes low level, the IC 53 stops the oscillation operation, and a signal corresponding to the tracking error signal from the input terminal 46 is taken out from the operational amplifier 47, and the signal is output from the transistors Q ₂ to Q ₅ and the resistors R ₇ to
A tracking control coil drive circuit consisting of _R11 converts the voltage into a current, amplifies it to a required level, and supplies it to the tracking control coils _L1 to _L4 .

As a result, a current with a level and direction according to the tracking error signal is passed through the coils L ₁ L ₄ , and magnetic fields of different types are induced at the end faces of the opposing coils as shown in FIG. 5
6 acts as a repulsive force and the other as attraction, and the cantilever 14 moves in the direction perpendicular to its longitudinal direction (radial direction of the disk 10) in the direction in which the track deviation is to be corrected, and in the direction in which the track deviation is to be corrected. A small displacement is made by the amount of displacement that should make the value zero.

On the other hand, in special cases such as during still image playback or double-speed playback, in which the scanning track is forcibly changed more than once per revolution of the disk 10, the input signal levels of both input terminals 50 and 51 are set to normal playback. The oscillation operation of the IC 53 is stopped as in the above case, but when the scanning track is forcibly changed, the negative polarity pulse shown in FIG. A positive pulse shown at B enters, and the emitter output signal waveform of transistor _Q1 becomes a pulse shown at C in FIG. After the DC component of this pulse is blocked by the capacitor _C1 , it is supplied to the coils _L1 to _L4 through the operational amplifier 47 and the tracking control coil drive circuit, respectively. As a result, the regeneration needle 13 is forcibly moved by one track pitch toward the outer circumference or inner circumference of the disk.

Next, when the pickup housing 12 and the carriage 15 come to the rest position 12a after the normal playback or special playback described above, the elevator 25 and lifter 26 are moved as described above in order to collect the disk 10 into the empty disk storage case. It begins to rise to the position shown by the two-dot chain line in FIG. 4, and as it rises, the rotating body 23 and brush 29 shown in FIGS. 1 to 3 rotate, respectively. At the same time, a stylus pressure application signal is applied to the stylus pressure application coil, and the tip of the regenerating needle 13 is brought into contact with the surface of the brush 29. This stylus pressure application signal is at a low level and is applied to an input terminal 51 shown in FIG. 7, and a low level rest position detection signal is applied to an input terminal 50. Therefore, a high level signal is taken out from the NOR circuit 52 and sent to the terminal 53a of the IC 53.
IC53 starts oscillating operation,
An oscillation pulse of, for example, 200 Hz, which has a larger pulse width than the pulse shown in FIG. 9C, is output from the output terminal 53b. This oscillation pulse is generated by the pulse output circuit 5.
4 to the base of transistor _Q1 ,
Furthermore, the capacitor is taken out from the emitter.
After the DC component is blocked by C ₁ , the operational amplifier 47,
The driving current is supplied to the tracking control coils L ₁ to _{L 4} through the tracking control coil drive circuits, respectively.

As a result, while the elevator 25 and lifter 26 are ascending, a signal is supplied to the tracking control coils L ₁ to _{L 4} to vibrate the regeneration needle 13 and the cantilever 14 in the track width direction at a cycle of 1/200 seconds. Therefore, the needle tip of the regenerated needle 13 is in contact with the surface of the rotating brush 29, and
It vibrates in the direction C in FIG. 1 on a surface substantially parallel to the rotational surface of 9. Thereby, the dust attached to the electrode 13b of the regenerated needle 13 and its surroundings, and the dust attached to the sliding contact surface 13c can be suitably removed. Incidentally, since the above-described rising period of the elevator 25 and lifter 26 is about 2 seconds, the needle tip is vibrated about 400 times.

Next, when the elevator 25 and lifter 26 rise to the upper limit position shown by the two-dot chain line in FIG. 4, the rising position detection switch operates to stop generating the stylus pressure application signal. This causes the regenerated needle 13 to move to the brush 2.
While the signal level of the input terminal 51 becomes high level, the signal level of the input terminal 51 becomes high level. Therefore, the output signal of the NOR circuit 52 becomes low level, the oscillation operation of the IC 53 stops, and the base of the transistor _Q1 becomes a constant level. At this time, since the disc 10 is not being reproduced, no tracking error signal enters the input terminal 46. Therefore, from the above, the driving current for slightly displacing the tip of the regeneration needle 13 is not supplied to the tracking control coils _L1 to _L4 , and the vibration of the tip of the regeneration needle 13 is also stopped. Become. That is, the tip of the regeneration needle 13 is vibrated only during the period when the brush 29 is rotating.

Application Example In the above embodiment, the brush 29 is rotated, but the desired effect can be similarly obtained by linearly moving it in the direction of arrow A or the opposite direction. Further, although the brush 29 is caused to rotate (or may be linearly moved) by utilizing the rise of the elevator 25, the above-mentioned elevator 2
5. If a disk support elevating mechanism such as a lifter 26 is not provided, the linear or rotational movement of the brush 29 and the vibration of the needle tip are controlled for a certain period of time by detecting that the pick-up casing 12 or the like has come to the rest position 12a. Of course, they may be performed simultaneously.

Effects As described above, according to the present invention, the needle tip of the regenerated needle is brought into contact with the brush that is rotating or linearly moving, and the needle tip is vibrated on a plane substantially parallel to the brush surface. Therefore, it is possible to remove dirt (including dust) attached to the electrode surface of the regenerated needle and its surroundings, and it is also possible to use a brush made of bristles that has a cross section that can be considered flat compared to the area of the sliding surface of the regenerated needle. Since the needle tip is vibrated on the surface, it is possible to remove dust attached to the sliding surface of the recycled needle.
In addition, since the needle tip is vibrated, it is possible to prevent the needle tip from jumping on the brush, and it is also possible to increase the chances of contact between the needle tip and the brush, thereby increasing the cleaning effect compared to conventional methods. It has many features such as the ability to

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a schematic configuration of an embodiment of the device of the present invention, FIGS. 2 and 3 are a plan view and a side view showing an embodiment of the main part of FIG. 1, respectively, and FIG. 5 is a sectional view showing an example of the essential parts of the reproducing apparatus to which the present invention can be applied; FIG. 5 is a perspective view showing an example of the mechanism of the essential parts of the reproducing apparatus shown in FIG. 4; and FIG. 6 is a disk and reproducing needle. FIG. 7 is a circuit diagram showing an embodiment of the main part of the device of the present invention, and FIG. 8 is a partially enlarged perspective view showing an example of the sliding situation with the regeneration needle of the regeneration device to which the device of the present invention can be applied. 9A to 9C are plan views showing an example of the configuration with tracking control coils, etc.
This is a time chart for explaining the operation of the illustrated circuit. 10...disc, 11...turntable,
12...Pick-up housing, 13...Regeneration needle, 1
4... Cantilever, 15... Carriage, 21
... Rod, 22 ... Rubber pipe, 23 ... Rotating body, 25 ... Elevator, 26 ... Lifter, 2
9... Brush, 31... Clutch arm, 33...
... Motor, 35 ... Lifting mechanism, 46 ... Input terminal, 48, 49 ... Pulse input terminal, 50 ... Rest position detection signal input terminal, 51 ... Needle pressure application signal input terminal, 52 ... NOR circuit, 53...Astable multivibrator IC, 54...Pulse output circuit, 56...Permanent magnet, _L1 to _L4 ...Tracking control coil, _L5 ...Jitter correction coil.

Claims (1)

[Scope of Claims] 1. Recorded signals of the recording medium are detected by detecting changes in capacitance formed between the recording medium and an electrode of a reproducing needle that slides and scans over the recording medium having an electrode function. A capacitance change detection type regeneration device that regenerates a regenerating needle, comprising: a brush that is made of bristles that has a cross section that can be considered to be flat compared to the area of the sliding surface of the regenerating needle, and that performs rotational or linear motion; During the period of movement, the needle tip of the regeneration needle is brought into contact with the brush, and a vibration signal is supplied to a control coil for moving the regeneration needle on a track during regeneration on a plane substantially parallel to the brush surface. What is claimed is: 1. A needle tip cleaning device for a capacitance change detection type reproduction device, characterized in that the device comprises means for vibrating the brush in a direction substantially perpendicular to the direction of movement of the brush.