JPH0223560A - Magnetic tape driving controller - Google Patents

Abstract

PURPOSE:To widely control the magnetic tape speed from a low speed to a high speed with simple constitution by performing a tape speed control with an output of a prescribed detector for detecting the tape traveling speed. CONSTITUTION:Light from an LED 38a passes along its course 41 to make incident upon a phototransistor (PT) 33a. Rotational displacement of a roller 23 is converted into an electric output of the PT 33a because the light is interrupted by slit plates 35a and 35b. Then, light from an LED 38b passes along its course 42, and since this light is interrupted by a slit pattern 23a of the roller 23, it is converted into an electric output of a PT 33b. Output signals 33c and 33d from the PTs 33a and 33b respectively for the tape speed detector 33 inclusive of the roller 23 are changed over to be inputted to a control circuit 31, and in response to this input, reel base driving devices 26 and 28 are controlled on their driving rotational speed. By this method, the tape speed can be controlled over a wide range.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic tape drive control device that can be used in rotary head type tape recorders and the like.

2. Description of the Related Art A conventional magnetic tape drive control device of this type is based on the configuration shown in, for example, Japanese Unexamined Patent Publication No. 58-122606, and one application example of the configuration is a model as shown in FIG. It is indicated by.

That is, the tape cassette 2 held in the base vi1 of the device
The magnetic tape 3 (hereinafter referred to as tape) that has come out from the fixed tape guide 4 a s first tape guides 5 a, 5 b, 5
c, 5d, second tape guide 6, fixed tape guide 4
A tape bus is configured to return to the tape cassette 2 while being guided by a tape guide drum 8 containing a built-in rotary magnetic head 7a and 7b (hereinafter referred to as heads). During recording, the tape 3 is driven by a capstan 9 and a pinch roller 10, and is wound onto a take-up reel (not shown) by a take-up reel stand 12a driven by a take-up reel stand drive device 11. During fast forwarding, take-up reel stand drive device 1
1 operates independently. In addition, the supply side reel stand drive device 13
is for driving the supply side reel stand 12b when rewinding the tape. On the tracks diagonally recorded on the tape, a recording pattern is determined so as to record a track detection signal for detecting a tracking error, as is well known in the 8IXII video system. Based on this recording pattern and in the reproduction state of the apparatus, the track detection circuit 14 generates a head tracking error signal for a predetermined track based on the output signals of the heads 7a and 7b. The control circuit 15 uses this tracking error signal as an input signal to drive and control the capstan motor 16, and controls the speed of the tape 3 so that the heads 7a and 7b always scan on a predetermined recording track.

In the recording state of the apparatus, the control circuit 15 operates to keep the rotational speed of the capstan motor 16 constant, thereby keeping the tape speed constant and the pitch of the tracks to be recorded constant. The cassette 2 has a tape guide boss 2a.

2b and a recess 2c are provided, and immediately after the cassette 2 is mounted on the board 1, the tape is in the position shown in 3a, and the above-mentioned first tape is placed in the space between the tape 3a and the recess 2c. Guide 5 a, 5 b+
5 C15d, the second tape guide 6, and the pinch roller 10 are configured to fit in the positions indicated by broken lines, respectively. Then, by a drive device (not shown), the first tape guides 5a, 5b, 5c, 5d, the second tape guide 6, and the pinch roller IO are respectively displaced from the positions shown by broken lines to the positions shown by solid lines, and the recording apparatus is started. Or it is configured to be brought to a state where it can be reproduced.

Problems to be Solved by the Invention However, in such a configuration, it is difficult to control the tape speed over a wide range from low speed to high speed. It is possible to control low-speed running of the tape, but when controlling high-speed running during fast forwarding or rewinding, the supply or take-up reel table drive device must be controlled to keep the tape speed constant in response to the ever-changing reel diameter. requires another means. Examples of alternative means include a combination of means for detecting the rotational speed of the reel stand and means for performing demonstration based on this detection, or providing a separate tape speed detector, but in any case, This cannot be realized with a simple configuration, and is a problem in conventional examples.

Therefore, the present invention has been made in order to provide a simple device configuration that can control tape speed over a wide range from low speed to high speed.

Means for Solving the Problems The technical means of the present invention for solving the above problems is a tape speed detection system that includes a roller that rotates in contact with a magnetic tape, and a conversion element that converts the rotational displacement of this roller into an electrical signal. and a control circuit that controls the rotational speed of the supply or take-up reel base according to the output of this detector.Furthermore, this tape speed detector detects the low running speed of the tape by detecting the axial transmission of the roller. A first conversion element that optically detects light through a slit plate that intermittents according to the rotational displacement of the twenty rollers, and a first conversion element that detects light optically through a slit plate that intermittents according to the rotational displacement of the twenty rollers. A second conversion element is provided for optical detection through a slit pattern on the surface, and the output of the first or second conversion element is selected by an electric switch and input to the control circuit.

action The effect of this technical means is as follows.

That is, according to the configuration of the present invention, when the tape is run at a low speed and a signal is recorded on it, the control circuit controls the drive of the take-up reel base based on the output of the first conversion element. is activated, and when the tape is run at high speed and the beginning of the tape is performed, it is sufficient to control the drive of the supply or take-up reel base based on the output of the second conversion element. Tape speed control from low to high speeds can be achieved by simply switching between the first and second conversion elements, and there is no need for conventional low-speed drive elements such as capstans and pinch rollers, making it simple. This can be realized with a simple configuration. Further, by using this transmitted light type slit plate, it is possible to obtain the high resolution required when running the magnetic tape at low speed. On the other hand, increasing the resolution when running at low speeds results in a decrease in output and instability when running at high speeds, but by using a reflective slit pattern on the circumferential surface of the roller, the light from the slit plate can be reduced. It is possible to detect the rotation independent of the path, and it is possible to change the optimum stable detection output when the magnetic tape is running at high speed. Such a tape speed detector can be realized with a simple configuration using a single roller.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings. FIG. 1 is a plan view showing a configuration model of an embodiment of the present invention, in which 17 is a board of the device, and a tape cassette 18
1 shows a state in which the board 170 is mounted at a predetermined position.

The tape 19 includes a fixed tape guide 20, first tape guides 21a, 21b, 21c, 21d1, a second tape guide 22, a speed detector roller 23, and a tape guide drum 25 containing rotary heads 24a, 24b.
are guided by. A take-up reel stand 27 is rotationally driven by a take-up reel stand drive device 26 including a motor. A supply reel stand driving device 28 including a motor drives the supply reel stand 29 in the rewinding direction, and is activated when the rewinding state of the apparatus is selected by a mode selection device (not shown). The track detection circuit 30 includes the heads 24a and 2, as explained in the prior art section above.
4b is a circuit for reproducing pilot signals and synchronization signals on tracks recorded diagonally on the tape 19, and detecting an error between the track to be reproduced and the track being scanned by the head, that is, a tracking error. The details are a well-known technique in the R-DAT (rotary head type digital audio tape recorder) that has been put into practical use, so the explanation will be omitted. The control circuit 31 is an electric switch 32a
, 32b selectively switch and input the output signal of this track detection circuit or the two output signals 33c and 33d of the speed detector 33 (detailed explanation in FIG. 2) including the roller 23, and according to this input. This circuit controls the drive rotation speed of the reel stand drive device 26 or 28 as described below. That is, electrical switch 32a.

When 32b is in the state shown in the figure, the device is in the recording state, and the output 33c from the first phototransistor 33a for detecting the low running speed of the speed detector 33 is input to the control circuit 31, and the control circuit 31 The take-up reel stand drive device 26 so that the output of the speed detector 33 including the
By controlling the driving speed of the tape 19, the running speed of the tape 19 is kept constant. Further, when the electric switches 32a and 32b are in contact with the contacts on the upper side of the diagram, the device is in the reproducing state, and the control circuit 31 controls the take-up reel drive unit 26 so that the tracking error of the track detection circuit 30 is minimized.
control the driving speed.

When the electrical switches 32a and 32b are in contact with the contacts on the lower side of the figure, the device is in a fast forward or rewind search state, and mode selection between fast forward and rewind is performed by the aforementioned mode selection device (not shown). . In this state,
The output 33d from the second phototransistor 33b for detecting the high-speed running speed of the speed detector 33 becomes an input to the control circuit 31, and this control circuit 31 is connected to the speed detector 33.
The drive speed of the take-up reel stand drive device 26 or the supply reel stand drive device 28 is controlled so that the output is constant. In this search state, the control system operates to control the travel at a speed approximately 200 times faster than tape recording.

The cassette 18 is provided with tape guide posts 18a, 18b and a recess 18c. Immediately after the cassette 18 is mounted on the board 17, the tape is in the position shown at 19a, and the tape is placed in the space surrounded by the tape 19a and the recess 18c. , the above-mentioned tape guides 21a, 21b.

21c, 21d, and 22 are configured to fit in the positions indicated by broken lines, respectively. These tape guides 21a
, 21 b + 21 c + 21 d and 22 from the position shown by the broken line in the figure to the position shown by the solid line in the figure is a well-known structure, and the explanation will be omitted. Note that the first
The tape guides 21a, 21b, 21c, and 21d wind the tape around the tape guide drum 25 (9 in the embodiment).
0°) guide, and the second tape guide 22 is a guide for winding the tape around the roller 23.0 Figure shows the tape starting state, and the supply side tape roll 19
b is the maximum diameter, and the take-up side tape roll 19c is at the minimum diameter, but when the tape has finished winding, the take-up side tape roller is at the maximum diameter as shown by 19d. The roller 23 is
In any state in which the take-up tape roll reaches its maximum diameter from the minimum diameter to the maximum diameter, the tape does not come into contact with the guide post 18b inside the tape cassette, nor does it come into contact with the right wall 18d inside the tape cassette, the so-called tape It is arranged so that its outer periphery is located within the pass zone, thereby preventing unnecessary friction loss in the tape running system. Furthermore, the second tape guide 22 has a sufficiently smaller diameter than the conventional pinch roller, and the first tape guide 21a,
Similar to 21b, 21c, and 21d, the dimensions are such that they fit comfortably in the space surrounded by the tape 19a and the recess 18c.

FIG. 2 is a perspective view showing the configuration of the speed detector 33 described in FIG. 23a (in the example, 10 white and 10 black slits) are formed.

FIG. 3 is a sectional view showing the configuration of the speed detector described in FIG. 2. 19 is a cross section of the tape. The roller 23 is made of a light-transmissible material, 35a is a slit plate that is in close contact with the lower surface of the roller 23 and rotates as one, and has 200 slits formed therein, and 35b is a slit plate that is attached to the housing 36 of the speed detector. A fixed slit plate, 33a is a phototransistor that is a first conversion element, 33b is a phototransistor that is a second conversion element, and 38a and 38b are LEDs.
, 39a, 39b are prisms, and 40a, 40b are bearings that support the rotating shaft 34. With this configuration, first LE
The light from D38a passes through path 41 and reaches the first phototransistor 33a. The rotational displacement of the roller 230 is converted into an electrical output of the first phototransistor 33a since the light is interrupted by the Surin Vi35a, :3sb. The light from the - direction LED 38b passes through 42 paths and passes through the slit pattern 23a of the roller 23 described in FIG.
Since the light is intermittent, it is converted into an electrical output of the second phototransistor 33b. By using an optical speed detector using a prism in this manner, it becomes easy to attach the lower surface 36b of the housing 36 to the upper surface of the base 117 shown in FIG. 1, and it becomes possible to downsize the device. Further, by using the transmitted light type slit plate in this way, 200 output pulses can be changed per revolution, and the high resolution required when the magnetic tape runs at low speed can be changed. Furthermore, by using a reflective slit pattern on the roller circumferential surface that is rougher than the slits described above, the detection output of the phototransistor does not decrease even when the magnetic tape is running at high speed, where the alternating speed of light is high, and the detection output is stable. It will be done. Detection in these two modes can be realized with a simple configuration using a single roller.

In FIG. 1, a speed detector roller 23 is provided at the cassette entrance, and the first tape guide 21c.

21d and this roller 23, the second tape guide 22
By providing this, there is no need for a fixed tape guide provided in the tape bus zone at the cassette entrance, and moreover, it is possible to provide the roller 23 with the necessary tape winding angle. Furthermore, by arranging the roller 23 so that it is located just before the tape enters the cassette 18, the distance between the roller 23 and the take-up reel stand 27 can be minimized, especially during recording. It is possible to prevent speed control from becoming unstable due to unnecessary elastic elongation.

With the above configuration, the tape speed is kept constant in the recording state of the device, and diagonal tracks recorded on the tape are
Each track pitch is maintained at a predetermined track pitch. In the reproduction state of the apparatus, the rotary head always operates to scan on a predetermined track. However, by directly driving the tape on the reel stand without using a capstan, tape wow occurs due to errors such as reel eccentricity and engagement error between the reel and reel stand, but its value is It is also about 0.5% RMS, and exhibits sufficient performance especially for digital audio tape recorders.

In addition, in the search state of fast forwarding or rewinding, the tape running speed is directly detected and controlled by the speed detector 33, so the control is simpler compared to a method in which the tape winding diameter of the reel section, which changes from moment to moment, is controlled while being simulated. I can do it.

Effects of the Invention As described above, the magnetic tape drive control device of the present invention has the following effects:
Using the output of a detector that detects the magnetic tape running speed as a control input, it can control everything from low-speed running of the magnetic tape in the recording state of the device to high-speed running control such as in the search state for fast forwarding or rewinding the magnetic tape. It is constructed so that magnetic tape speed control can be performed. Furthermore, this speed detector includes a first conversion element for detecting a low running speed of the magnetic tape and a second conversion element for detecting a high running speed of the magnetic tape. By arranging a transmission light type slit plate correspondingly and a reflection type slit pattern on the roller circumferential surface corresponding to the second conversion element, it is possible to perform detection with high resolution when the magnetic tape is running at low speed, and During running, the magnetic tape follows a magnetic tape running at high speed without causing a drop in output due to responsiveness, making stable speed detection possible. Therefore, according to the present invention, it is possible to provide such a device with a simple configuration, and it is possible to achieve the effects of realizing low cost and high reliability.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the overall configuration of one embodiment of the present invention, and FIG.
3 is a sectional view showing the structure of the speed detector, and FIG. 4 is a plan view showing an example of a conventional magnetic tape drive device. 18... Tape cassette, 19... Magnetic tape, 23... Speed detector roller, 23
a... Slit pattern, 25... Tape guide drum, 26... Take-up reel stand drive device, 27... Take-up reel stand, 28... ...
- Supply reel stand drive device, 29... Supply reel stand, 31... Control circuit, 32a, 32b...
... Electric switch, 33 ... Speed detector, 3
3a...Phototransistor that is the first conversion element, 33b...Phototransistor that is the second conversion element, 35a, 35b...Slit plate, 38a, 38b- =LED. Name of agent: Patent attorney Shigetaka Awano Figure 4! Otsu PIK chutobeto outside table 1 to 0 kubo 5LLI)

Claims (1)

[Claims] A supply reel stand and a take-up reel stand that engage with a magnetic tape reel, a supply reel stand drive device that drives the supply reel stand in the rewinding direction, the take-up device, a roller that contacts the magnetic tape and rotates, and a speed detector that includes a conversion element that converts the rotational displacement of the roller into an electric signal and detects the running speed of the magnetic tape; and the output of the speed detector is used as an input to drive the supply reel stand drive device or the take-up reel stand. The speed detector includes a control circuit that controls the operation of the device and the running speed of the magnetic tape, and the speed detector includes:
a first conversion element that optically detects the low running speed of the magnetic tape during recording through a slit plate that intermittents the transmitted light in the axial direction of the roller in accordance with the rotational displacement of the roller; A second conversion element is provided for optically detecting a high running speed during fast forwarding or rewinding through a slit pattern on the circumferential surface of the roller, and the output of the first or second conversion element is selectively adjusted. 1. A magnetic tape drive control device comprising: an electric switch for switching to and inputting to the control circuit.