JPH0648580Y2 - Tape beginning and end detecting device of magnetic recording and reproducing device - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) The present invention is a magnetic tape provided in a magnetic recording / reproducing apparatus such as a video tape recorder (hereinafter referred to as VTR) and wound around a tape cassette. The present invention relates to a tape leading end and trailing end detecting device for detecting both ends of a tape.

(Prior Art) In a tape cassette used in a VTR or the like, transparent leader tapes are usually provided at both ends of the magnetic tape in order to detect both ends of the magnetic tape wound around the tape cassette. The mechanism for detecting the leader tape is conventionally constructed as shown in FIGS. 3 and 4. Third
In the figure, the cassette 2 inserted in the front loading device 1 is attached to a cassette holder (not shown),
It is driven by the motor 4 via the gear group 3 and is loaded into a predetermined position together with the cassette holder. At this time, the LED 5 which is a light source erected on the lower surface of the front loading device 1 is inserted into the insertion hole 2a formed at the substantially center of the cassette 2 in the longitudinal direction as shown in FIG. On the other hand, sensors 6a and 6b such as phototransistors are provided on both side surfaces of the front loading device 1, respectively. On both sides of the cassette 2, the LED 5
Opening holes 2b are formed so that the light emitted from each of the sensors 6a and 6b is incident on the sensor 6a, 6b. The optical axis 7 connecting the LED 5 and the pair of sensors 6a, 6b passes through the outside of the minimum diameter of the magnetic tape 9 wound around the reel 8 of the cassette 2.

According to the leader tape detection mechanism configured as described above, when the magnetic tape 9 is pulled out and wound on the cylinder (not shown), the magnetic tape 9 wound on one reel 8 is the tape top or the tape. In the vicinity of both ends of the end, the optical axis 7 passes through the transparent leader tape. As a result, the light emitted from LED5 is the sensor on the take-up reel side.
The tape top or the tape end can be detected by being incident on the sensor 6b on the side of 6a or the supply reel.

However, according to the above-mentioned conventional leader tape detecting mechanism, one sensor 6a, 6b is required on each of the left and right sides of the front loading device 1 independently, and two circuits are required accordingly. As a result, there has been a problem that the number of parts is increased, the cost is increased, and a space is required.

(Problems to be Solved by the Invention) As described above, according to the leader tape detecting mechanism of the conventional magnetic recording / reproducing apparatus, two sensors are required and two sets of circuits are required accordingly. As a result, there are problems that the number of parts is increased, the cost is increased, and a space is required.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a tape start end and end detection device of a magnetic recording / reproducing apparatus which can reduce the number of parts, reduce the cost, and downsize the apparatus. With the goal.

[Structure of the Invention] (Means for Solving the Problem) The present invention provides a light-transmitting leader tape at both ends of a magnetic tape wound around a reel provided in a tape cassette. The tape start and end of a magnetic recording / reproducing apparatus for guiding the light emitted from the magnetic tape to the magnetic tape on the supply side and the magnetic tape on the winding side respectively, and detecting the light passing through the leader tape by a light receiving element to detect the end of the magnetic tape. In the apparatus, there are provided a first light guide means for guiding one of light passing through the leader tapes on the supply side and the winding side to a single light receiving element via an optical fiber, and the leader tapes on the supply side and the winding side. Second light guide means for guiding the other of the light passing therethrough to the single light receiving element directly or via an optical fiber, detection means for detecting the rotation direction of the reel, and output of the single light receiving element. And those provided with the discriminating means for discriminating the starting end or terminal end of the tape based on a detection result of said detecting means.

(Operation) According to the above configuration, of the light emitted from the light source and passing through the leader tape on the supply side or the winding side, one light passes through the optical fiber, the other directly, or both lights respectively pass through the optical fiber. The light is then received by the same light receiving element. Therefore, it is possible to reduce the number of parts and the cost by using only one light receiving element, which was required in the past. Further, by guiding both lights to the light receiving element via the respective optical fibers, this light receiving element can be arranged at an arbitrary position, and space saving around the cassette can be realized. Whether the leader tape detected at this time is the tape top side or the tape end side can be determined by the winding direction of the cassette reel.

(Embodiment) An embodiment of a tape start end and end detection device of a magnetic recording / reproducing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, parts that are the same as or equivalent to those in the conventional example shown in FIG. A feature of this embodiment is that a sensor 6 such as a phototransistor, which is a light receiving element, is provided only on the side surface of the front loading device 1 on the winding side, and is provided on the optical axis 7 on the supply side surface of the front loading device 1. The body 10 and the sensor 6 are connected by an optical fiber 11,
The starting point and the ending point of the tape are discriminated from the output of the sensor 6 and the rotation direction of the reel.

Next, the operation of this embodiment will be described. The tape top of the magnetic tape 9 is pulled out from the supply-side reel 8a,
In the state where the tape is wound around 8b, the light emitted from the LED 5 passes through the leader tape on the tape top side and enters the sensor 6 through the opening 2b formed in the side surface of the cassette 2. Further, when the magnetic tape 9 is entirely wound on the take-up reel 8b, the light emitted from the LED 5 passes through the leader tape on the tape end side and enters the sensor 6 through the optical fiber 11. Then, the tape top or the tape end of the magnetic tape 9 is detected. Whether the detected tape end is the beginning or end of the tape is determined by the rotation detecting means (not shown) that detects the direction of rotation of the cassette reel at the time of detecting the leader tape, and based on the detection result, the determination (not shown) is made. By means.

According to the present embodiment, the number of sensors 6 required to be two in the past is one.
Assembled, it is possible to reduce the number of parts and cost. Moreover, the space around the front loading device 1 can be saved.

In the above embodiment, the sensor 6 is replaced by the front loading device 1.
Although the case where the sensor 6 is provided on the side surface on the winding side has been described, the sensor 6 may be provided on the side surface on the supply side of the front loading device 1 and the optical fiber 11 may be connected to the side surface on the winding side.

Further, as shown in FIG. 2, the front loading device 1
Cylinders 10 and 12 provided on both sides of the optical axis 7
Alternatively, one ends of the optical fibers 11 and 13 may be connected to each other, and the other ends of the optical fibers 11 and 13 may be connected to the separately arranged sensor 6. According to this embodiment, the sensor 6
Can be moved to any position, and the space around the front loading device 1 can be further saved.

Further, in general, a VTR uses information indicating in which direction the reel is rotating in order to calculate the tape counter, the remaining tape amount, etc., and is usually provided with a reel rotation direction detecting means. Therefore, the present invention has the advantage that the detecting means can be used, there is no need to provide new means as the detecting means, and the configuration is simplified.

Further, in each of the above-mentioned embodiments, the tape start end and end detection device provided in the VTR has been described, but the same effect can be obtained by applying it to another magnetic recording / reproducing device.

[Advantages of the Invention] As described above, according to the tape start end and end detection device of the magnetic recording / reproducing apparatus of the present invention, it is possible to use one sensor for each of the light source and the light receiving element.
It is possible to reduce the number of parts and costs.
Moreover, the space around the front loading device can be saved, and the magnetic recording / reproducing device can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a VTR front loading device provided with an embodiment of a tape start and end detecting device according to the present invention, and FIG. 2 is a perspective view showing another embodiment of the present invention. FIG. 3 is a perspective view showing a VTR front loading device provided with a conventional tape start and end detection device, and FIG. 4 is a plan view showing a conventional tape start and end detection device. 2 …… Cassette 5 …… LED (light source) 6 …… Sensor (light receiving element) 9 …… Magnetic tape 11,13 …… Optical fiber

Claims (1)

[Scope of utility model registration request] 1. A light-transmitting leader tape is provided at both ends of a magnetic tape wound around a reel provided in a tape cassette, and light emitted from one light source is provided on the supply side and the winding side. A tape start end and end detection device of a magnetic recording / reproducing apparatus, which detects the end of the magnetic tape by receiving light passing through the leader tape by a light receiving element, respectively, the leaders on the supply side and the winding side. First light guide means for guiding one of the light passing through the tape to a single light receiving element via an optical fiber, and the other of the light passing through the leader tapes on the supply side and the winding side directly or via the optical fiber. Based on the output of the single light receiving element and the detection result of the detecting means. A tape leading end and trailing end detecting device of a magnetic recording / reproducing apparatus, comprising: a discriminating means for discriminating the beginning or the end of the tape.