JPS60243846A - Device for detecting tail end of cassette tape - Google Patents

Abstract

PURPOSE:To surely prevent uneven sound recording and omission in erasing at the tail end of a tape, by detecting the boundary between the magnetic tape section and leader tape section of the tape just before an eras head. CONSTITUTION:When a cassette tape 17 runs rightward from the left side, an erase head 11 for small window, sound recording and reproducing head 12, and pinck roller 14 are inserted into an erase head inserting window 4 at the left side, recording and reproducing head inserting window 5 at the center, and pinch rollr inserting window 7 at the right side, respectively. Then a pin-like light emitting body 9 is inserted into a capstan hole 1 in the remaining leftmost pinch roller inserting window 3 and the light of the light emitting body 9 is irradiated upon the running cassette tape 17. The light of the light emitting body 9 is reflected at the magnetic tape section of the tape 17, but passes through the leader tape section and received by an optical sensor 10, and thus the tail end of the tape 17 is detected. When the tail end is detected, measures, such as lowering the sound recording level, slowing the tape running speed, and so forth, are automatically taken to prevent uneven sound recording and omission in erasing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cassette tape end detection device used in various cassette decks and cassette tape recorders.

Conventional configuration and its problems In the past, the end of a cassette tape could not be accurately detected, resulting in uneven recording and omission of erasures before the leader tape. This is particularly a problem in double-speed models and high-speed dubbing devices, which have recently been developed.

The cause of this will be explained using FIGS. 4(A) to 4(E).

The magnetic tape (20) and the leader tape (21) are (A
), so when the end of the tape approaches the head (23) as shown in (B), the superimming tape (22) is attached to the head (23) as shown in (C). The end of 22) hits, and after jumping up like (D), it returns like (E). This phenomenon becomes more pronounced as the tape runs faster, and the range of unerased portions and uneven recording becomes wider.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks.The present invention is intended to eliminate the above-mentioned drawbacks of the prior art. It is an object of the present invention to provide a cassette tape end detection device that can accurately detect the end of a cassette tape.

Structure of the Invention In order to achieve the above object, the cassette tape end detection device of the present invention includes a light emitting body located on the upper side of the erasing head in the tape running direction when the cassette is installed, and a tape being sandwiched between the light emitting body when the cassette is installed. This configuration includes a photo sensor facing oppositely to each other.

According to such a configuration, the end of the magnetic tape portion can be detected before the erasing head, and processing such as erasing leakage prevention can be performed at that moment.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of the cassette, and FIG. 2 is an explanatory diagram of the main parts of the cassette inserted into a cassette deck equipped with a cassette tape end detection device according to an embodiment of the present invention.
The figure is a schematic cross-sectional view of the detection part of the cassette tape end detection device in one embodiment of the present invention, in which (1) and (6) are capstan holes, (2) are bed pads, and (3) and (7) are pinch rollers. Insertion window, (4) and (8) are erase head insertion windows,
(5) is the recording and playback head insertion window, (9) is the pin-shaped light emitter, (10) is the optical sensor, (11) is the erasing head for the small window, (12) is the recording and playback head, and (13) is the capstan. , (14) is a pinch roller, (15) is a tape guide,
(16) is a light emitting part, and (17) is a cassette tape.

As shown by the arrow in Figure 1, cassette tape (17)
When traveling from left to right, the erase head for the small window (11) is placed in the erase head insertion window (4) on the left, the recording/playback head (12) is placed in the recording/playback head insertion window (5), and the pinch head is placed on the right side. Pinch rollers (14) are inserted into the roller insertion windows (7), respectively.

Therefore, a pin-shaped light emitter (9) is inserted into the capstan hole (1) in the remaining left pinch roller insertion window (3) to illuminate the running cassette tape (17). As is well known, this cassette tape (17) is composed of a magnetic tape having a magnetic recording layer and a light-transmitting leader tape connected to both ends of the magnetic tape. The light is reflected by the magnetic tape portion and transmitted by the leader tape portion. The light transmitted through this leader tape is received by an optical sensor (10), and the end of the tape is detected.

In this way, after the end of the tape is detected before the small window erasing head (11), measures such as automatically lowering the recording level or slowing down the tape running speed to prevent omission of erasure can be taken to prevent uneven recording. Do the following.

In addition, in order to prevent light leakage from the pin-shaped light emitter (9), as shown in Figure 3, the light emitting part (1
6) and the vertical width of the light receiving opening of the optical sensor (10) is set to be less than or equal to the width of the cassette tape (17).

In addition, in the auto-reverse mechanism, when the cassette tape (17) runs from right to left, the small window erasing head (11) is placed in the erasing head insertion window (8) on the right side, and the pinch roller (14) is placed in the left side. Since the capstan (13) is inserted into the pinch roller insertion window (3) and the capstan hole (1) on the left side, the pin-shaped light emitter (9) needs to be inserted into the capstan hole (6) on the right side. There is.

Therefore, in a cassette deck with an auto-reverse mechanism, the pin-shaped light emitters (9) are placed in the left and right capstan holes (1) (6) depending on the running direction of the cassette tape (17).
) can be inserted and removed automatically, or make a special small hole in the cassette so that both the left and right pinch roller insertion windows (
3) Configure the pin-shaped light emitter (9) to be inserted into (7).

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the end of the tape, that is, the boundary between the magnetic tape section and the leader tape section, can be accurately detected before the erasing head, and recording irregularities and omissions in erasing at the end of the tape can be reliably detected. It becomes possible to prevent this.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a cassette, FIG. 2 is an explanatory diagram of a cassette inserted into a cassette deck equipped with a cassette tape end detection device according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a sectional view of the detection section of the cassette tape end detection device in FIG. (1) (6)... Capstan hole, (3) (7)
... Pinch roller insertion window, (9) ... pin-shaped light emitter,
(10)... Optical sensor, (11)... Erasing head agent for small window Yoshi Morimoto Private use 1 Figure 2 Figure 3 Figure 4 (/4) (B) (Cλ 173 re)

Claims (1)

[Claims] 1. A cassette tape terminal end comprising a light emitting body located on the upper side of the erasing head in the tape running direction when the cassette is installed, and a light sensor facing the light emitting body across the tape when the cassette is installed. Detection device. 2. The cassette tape end detection device according to claim 1, wherein the light emitter is pin-shaped and inserted into a capstan hole of the cassette. 3. The cassette tape end detection device according to claim 1, wherein the light emitting body is pin-shaped and inserted into the cassette through a small hole specially formed in the cassette.