JPH0512781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application This invention relates to a mechanism for blocking an end detection sensor of a multiplex tape recorder in which a plurality of cassette tapes are loaded into one tape storage section.

(B) Conventional technology As seen in, for example, Japanese Utility Model Application Publication No. 57-67267, a conventional duplex tape recorder stores a plurality of cassette tapes in one tape storage section and mutually connects them to a common capstan shaft. A dual tape recorder has been proposed in which an arbitrary cassette tape is run using a plurality of independently operating pinch rollers, and the end of the tape is detected using the tape tension at the end of the tape.

(c) Problems to be Solved by the Invention However, in the conventional duplex tape recorder, the end of the duplex tape recorder is detected using the tape tension at the end of the tape. It becomes impossible to perform termination detection. Therefore, the end of the tape has been detected when the reel cap or reel stand on which the first or second cassette tape is mounted stops rotating. However, in this case, the reel cap or reel stand on the side that does not operate during mode selection is stopped and an end detection operation is performed.

The present invention has been made in view of the above circumstances, and its object is to provide a dual-type end detection sensor that is equipped with a blocking means for disabling the action of each end detection sensor in accordance with each tape mode. An object of the present invention is to provide a mechanism for blocking an end detection sensor of a tape recorder.

(d) Means for Solving the Problems This invention has been made to solve the above problems, and includes storing two cassette tapes, the first and second cassette tapes, in a stacked manner in one tape storage section, and By associating one capstan shaft with the cassette tape and abutting the capstan shaft with first and second pinch rollers corresponding to the first and second cassette tapes, the first,
In a duplex tape recorder that selectively runs a second cassette tape at a constant speed, play lever means brings the first or second pinch roller into contact with the capstan shaft when the second cassette tape is moved from the non-operating position to the operating position. , capable of selectively assuming first and second tape mode positions, in each mode position cooperating with said play lever means to bring the first or second pinch roller into contact with the capstan shaft depending on the respective mode; a first end detection sensor means for detecting the end of the tape by rotation of the reel cap on which the first cassette tape is mounted; and a first end detection sensor means for detecting the end of the tape by the rotation of the reel stand on which the second cassette tape is mounted. a second end detection sensor means for detecting the end of the tape; and a block that acts on each end detection sensor means by taking each tape mode position with the mode select lever means and disables the action of each end detection sensor means. means, when the mode select lever means takes the first or second tape mode position, the blocking means acts on the end detection sensor means on the non-running tape mode side in accordance with each tape mode, and detects the end of the tape mode. The present invention provides a blocking mechanism for an end detection sensor of a duplex tape recorder, characterized in that the detection function is disabled.

(e) Effect According to the configuration of the present invention, when each tape mode position is selectively taken by the mode select lever means, the blocking means acts on the first and second end detection sensor means to detect the end of each tape mode. Since the operation is disabled, the end detection operation at the reel cap or reel stand on the stopped side is prevented.

(f) Examples The present invention will be described in detail below based on examples shown in the figures. Note that this invention is not limited thereby.

FIG. 1 shows the arrangement when the cassette tape is installed in this embodiment. A plurality of cassette tapes, for example two cassette tapes 1 and 2, are connected to a capstan 3 for FOR travel.
A capstan 4 for running the REV and a reel stand (not shown) are arranged coaxially on top of each other, and a magnetic head 5 and a pinch roller 6 are placed opposite the magnetic tape surface of the cassette tape 1. A magnetic head 7 and two pinch rollers 8 and 9 are arranged at positions facing the magnetic tape surface of the tape 2. The two magnetic heads 5, 7 are attached to the same reference stand 10, and each pinch roller 6, 8, 9 is structured to be able to operate independently.

FIG. 2 shows an example of the arrangement of operation buttons. In this example, regarding two cassette tapes, one has the functions of FOR only playback (PLAY), fast forward (FF), rewind (REW), and stop/eject (STOP/EJECT), and the other has FOR, FEV Playback (PLAY) and recording (REC) in both directions, fast forward (FF), rewind (REW), stop/
Eject (STOP/EJECT), pause (PAUSE)
It has each function. In the following explanation, 2
The FOR-only player located above the two cassette tapes is abbreviated as _T1 , and the FOR-only player located below the
The REV bidirectional recording and playback device will be abbreviated as _T2 .

The tape recorder in this embodiment operates in a continuous playback mode in which FOR and REV in _T2 are played continuously after the end of playback in _T1 , in a one-cycle mode and a continuous mode in _T2 , and in a continuous playback mode in which playback is performed in _T1 and simultaneously in T2 _. You can select from four editing modes for recording. Furthermore, in edit mode,
By operating both PLAY and REC buttons, T ₁ and
T ₂ works, and by operating only the PLAY button
It has the function of playing only _T1 .

FIGS. 3a and 3b show a sensor section for detecting the end of a cassette tape. The shaft 12 fixed to the take-up reel cap 1 to which the cassette tape 1 on the T ₁ side is attached is connected to the main chassis 13.
A receiving plate 14 is rotatably inserted into a hollow shaft 13a formed in the main chassis 13, and is fixed to a portion protruding from the back side of the main chassis 13. In addition, the receiving plate 14
A termination detection sensor 15 having a pressing protrusion 15a is attached to the lower shaft 12. This end detection sensor 15 is pressed against a stop plate 17 attached to the shaft 12 by the biasing force of a spring 16 installed between the receiving plate 14 and the rotation of the take-up reel cap 11 is transmitted to the end detection sensor 15. It is becoming more and more common. When the take-up reel cap 11 rotates, that is, T ₁
During operation, the pressing protrusion 15a of the end detection sensor 15 is pressed against the shaft 18a fixed to the back chassis 18.
Sensor lever 19 rotatably attached to
A sliding protrusion 19b protruding from the sensor lever 19 and directed toward the back chassis 18 presses the contact surface 19a of the back seat 18.
It slides on the circumferential surface of an eccentric swinging cam 20a formed coaxially with the end cam 20 which is rotatably held by the end cam 20. The end cam 20 rotates in the direction shown by arrow F, and this end cam 20 includes a swing cam 2.
In addition to 0a, when the sensor lever 19 is rotated in the direction of arrow E, the outer surface 20b
Thus, an arcuate cam 20c is formed which can slide into sliding contact with the sliding protrusion 19b.

During the operation of _T1 , when the rotation of the take-up reel cap 11 stops at the end of the cassette tape,
Along with this, the rotation of the end detection sensor 15 also stops, and the pressing protrusion 15a of the end detection sensor 15 no longer presses the sensor lever 19. The sliding protrusion 19b of the sensor lever 19 is pressed to the maximum diameter part of the sliding cam 20a by the end cam 20 rotating in the direction of arrow F, and then the sliding protrusion 19b of the cam 20c is pressed against the outer surface 20b of the cam 20c.
, and rotate the sensor lever 19 in the direction of arrow E using the shaft 18a as a fulcrum. sensor lever 1
9 stops the operating state of _T1 , as will be described later, by pressing a pin of an end select lever (not shown) that comes into contact with the arm 19c.

On the other hand, a hollow shaft 1 formed in the main chassis 13
A take-up reel stand 21 on which the cassette tape 2 on the _T2 side is mounted is inserted through the outer periphery of the tape 3a. The take-up reel stand 21 is provided with a gear 22 held by the main chassis 13 at a position that meshes with a gear 21a provided on the lower end surface thereof.
The support shaft 23 of the gear 22 that protrudes from the gear 22 to the back side of the main chassis 13 has an autostop having a receiving plate 24 and a pressing protrusion 25a, as in the case of the shaft 12 fixed to the take-up reel cap 11. A sensor 25 is attached. The auto-stop sensor 25 is pressed against a stop plate 27 attached to the support shaft 23 by the biasing force of a spring 26 attached between the support plate 24 and the rotation of the take-up reel stand 21 is transmitted to the auto-stop sensor 25. It is becoming more and more like this.
When the take-up reel stand 21 rotates, that is, during the _T2 operation, the pressing protrusion 25a of the auto-stop sensor 25 is pressed against the shaft 18 fixed to the back chassis 18.
Sensor lever 2 rotatably attached to b
The sliding protrusion 28b, which presses the contact surface 28a of the end cam 20 and extends from the sensor lever 28 toward the back chassis 18,
The sliding cam 20a is slid on the peripheral surface of the sliding cam 20a.

During TB operation, when the take-up reel stand 21 stops rotating at the end of the cassette tape, the gear 22 also stops rotating, and the pressing protrusion 25a of the auto-stop sensor 25 no longer presses the sensor lever 28. . sensor lever 28
, rotates in the direction of arrow E about the shaft 18b as a fulcrum, as in the case of the _T1 side, and presses a pin of an end select lever (not shown) that is in contact with the arm portion 28c, thereby stopping the operating state of _T2 .

As explained above, in the tape recorder of this embodiment, the two sensor levers 19 and 28, which operate by being transmitted with the rotation of the reel cap 11 on the _T1 side and the reel stand 21 on the _T2 side, are connected to the same end cam 20. At the end of the cassette tape, the sensor levers 19 and 28 are rotated to press the end select lever, and _T1 and
It is designed to stop or switch the operation of _T2 . In addition, in the tape recorder of this embodiment, when the rotation of the take-up reel cap 11 and the take-up reel stand ₂₁ stops, the end detection mechanism starts operating. It is equipped with a blocking mechanism that operates in accordance with each mode to prevent malfunctioning termination detection operations when only the _T2 side is operated. This blocking mechanism will be described later.

4 to 9 show the mechanical configuration of the tape recorder in this embodiment.
In FIG. 4, which shows the state in the editing mode, the mode select lever 30 disposed on the side of the sensor lever 28 has a continuous U-shape, and has a long U-shaped portion. It is slidable in the directions of arrows C and D in the figure by a pin 30b that engages with a hole 30a. A positioning pin 30c is formed in the U-shaped portion of the mode select lever 30 and projects toward the mode setting plate 31 having a plurality of V-shaped recesses. When the positioning pin 30c engages with the recess 31a of the mode setting plate 31, it enters the editing mode, when it engages the recess 31b, it enters the continuous mode at _T2 , when it engages the recess 31c, it enters the one cycle mode at _T2 , and When engaged with the recessed portion 31d, the continuous mode is set.

Further, the mode select lever 30 has a pin 30d projecting downward from the upper end of the U-shaped portion. This pin 30d has a convex shape that presses an inclined surface 32a formed on one side of the end select lever 32 and rotates the end select lever 32 in the E direction around the shaft 32f when the positioning pin 30c selects the edit mode. The portion 32b is moved to the position where it engages with the pin 33a formed on the lock plate release lever 33. At the tape winding end time, as each sensor lever 19, 28 on the T ₁ side or T ₂ side rotates in the E direction with the shaft 18a or shaft 18b as a fulcrum by the end cam 20, the pin formed on the end select lever 32 32c or pin 32
d and slide the end select lever 32 in the D direction. The convex portion 32b of the end select lever 32 slides the lock plate release lever 33 in the D direction, releasing the lock plate 59 and bringing it to a stopped state as described later.

On the other hand, as shown in FIG.
T ₂ engages with the recess 31b of the mode setting plate 31
When the continuous mode is selected in , the pin 30d of the mode select lever 30 does not press the inclined surface 32a of the end select lever 32. When the end select lever 32 is slid in the D direction at the end of tape winding, the convex portion 32b does not slide the lock plate release lever 33, and the pin 32e formed on the end select lever 32 engages the arm of the trigger lever 34. Press 34a. By this pressing, the trigger lever 34 is rotated in the E direction about the shaft 34b and disengaged from the protrusion 35a formed on the logic cam gear 35. cam gear 3
5 is rotated in the E direction. logic cam gear 3
5 has two cams 36 and 37 integrally formed on one side, and a rotational force in the E direction in the figure is applied by a starting spring (not shown), but normally,
The toothless portion 35b is locked in a position corresponding to the gear 38 rotated by the rotational drive source.

The mode select lever 30 has a built-up portion 39e formed in a shaded area in the figure when the continuous mode is selected.
7 and is pressed by the cam 37 as the logic cam gear 35 rotates at the end of tape winding. Then, the positioning pin 30c of the mode select lever 30 is inserted into the recess 31d of the mode setting plate 31.
c to switch to 1 cycle mode at _T2 . A pin 39a formed on a program interlocking lever 39 configured to be slidable in the directions of arrows A and B is brought into contact with a trapezoidal convex portion 30f formed on the side wall of the mode select lever 30 by the biasing force of a spring 40. being touched. The program interlocking lever 39 has an arm portion 39b extending toward the logic cam gear 35, and a pin 39c projecting toward the logic cam gear 35 is formed at the tip thereof.

When the logic cam gear 35 rotates at the end of tape winding in the _T2 mode, the pin 39c of the program interlocking lever 39 is connected to the logic cam gear 3.
5 is pressed against the inner surface 36a of the cam 36,
The program interlocking lever 39 is slid in the B direction. On the other hand, at the end of tape winding in continuous mode, the pin 39a of the program interlock lever 39 comes into contact with the inclined surface 30g of the mode select lever 30, and the pin 39c of the program interlock lever 39 comes into contact with the inclined surface 30g of the mode select lever 30.
Since it is sliding in the A direction more than in T ₂ mode,
When the logic cam gear 35 rotates, the pin 39c passes outside the cam 36, and the program interlocking lever 3
9 does not slide. The pin 39d formed at the left end of the program interlocking lever 39, which is slid in the B direction at the end of tape winding in the _T2 mode,
Since the arm portion 41a of the inverted L-shaped cam lock lever 41 is pressed, the cam lock lever 41 is pressed against the shaft 41b.
The program switching cam gear 42 is rotated in the F direction using the program switching cam gear 42 as a fulcrum, and the engagement with the protrusion 42a formed on the program switching cam gear 42 is released.

The program switching cam gear 42 is given a rotational force in the F direction by a starting spring (not shown), is engaged with a gear 43 rotated by a rotational drive source, and is rotated in the F direction. Therefore, the cam lock lever 41 engages with the protrusion 42b of the program switching cam gear 42, and the program switching gear 4
Since the second missing tooth portion 42c moves to the position corresponding to the gear 43, the program switching gear 42 is stopped from rotating. Pin 41 of cam lock lever 41
c is a long hole 44 formed in the program lever 44
By pressing the program lever 44 in the D direction, the program switching cam gear 42 can be rotated. 45 is a program switching cam formed integrally with the program switching cam gear 42, and the switching cam 45 has an elongated hole 4.
6b and a pin 46c that engages therewith, the arm portion 46a of the program switching lever 46 is movable in directions A and B by a spring 47;
is in contact.

Shaft 46 formed on program switching lever 46
An RVS lever 48 is rotatably attached to d. The movement of the RVS lever 48 is restricted by a pin 30h formed on the mode select lever 30 that engages with a long hole 48a provided therein. Arm portion 46h of program switching lever 46
A program interlocking lever 49 slidable in directions A and B is attached to a pin 46e formed in , and is biased in direction A by a spring 50. Further, the shafts 46f and 45g formed on the program switching lever 46 are provided with switching levers 51 and 4.
2 are rotatably attached to each other, and elongated holes (not shown) provided in their arm portions 51a and 52a are engaged with engagement pins 49a formed in the program interlocking lever 49, and the switching levers 51, 5
2, each movement is regulated.

Positioning pin 30 of mode select lever 30
When c is slid from the T ₂ mode to the continuous mode, the pin 30i formed on the mode select lever 30 presses the arm 52b of the switching lever 52, and the positioning pin 30c is slid from the T ₂ mode to the editing mode. When the pin 30j formed on the mode select lever 30 presses the arm portion 51b of the switching lever 51, the switching levers 51 and 52 are rotated about the shafts 45f and 46q, respectively, and the program linking lever 49 is rotated about the shafts 45f and 46q.
is slid in the B direction.

10 to 16 show the sensor killer and pinch roller switching mechanism of the tape recorder in this embodiment.

FIG. 10 shows the stopped state in the editing mode. It has a program lever 44 and a pin 53a.
REC lever 53, PLAY lever 54 with pin 54a, REW lever 55 with pin 55a,
FF lever 56 with pin 56a, STOP lever 57 with pin 57a, and PAUSE lever 5
8 are attached so as to be slidable in the C and D directions in the figure, respectively, and are each biased in the C direction by a spring (not shown). 59 is a lock plate attached so as to be slidable in directions A and B, and this lock plate 59 has a spring (not shown)
The pins 5 are biased in the direction B by the
Convex portions 59a to 59d are formed at respective positions of the locking plate 59 corresponding to the levers 3a to 56a to lock the respective levers 53 to 56.

In addition, an inclined surface 59e formed on the lock plate 59
A pin 57a formed on the STOP lever 57 is projected at a position corresponding to
56 is disengaged. Furthermore, the lock plate 59
A pin 33c formed on the lock plate release lever 33 is projected at a position corresponding to the inclined surface 59f of the tape.
3c presses against the inclined surface 59f, and the lock plate 59 releases each of the levers 53-56. A PAUSE operating lever 75 that rotates around a shaft 74a is in contact with the tip of the PAUSE lever 58.

The T ₁ side pinch roller lever 60, the T ₂ side FOR pinch roller lever 61, and the T ₂ side REV pinch roller lever 62 are rotatably attached to support shafts 63 to 65, respectively, and are connected to springs 66 to 68 and pins (Fig. (not shown).
In addition, each pinch roller lever 60 to 62
During playback or recording, the roller portions 60a to 60a are
Springs 72 to 74 are attached to press 62a to capstans 69 to 71. The _T2 side pinch roller levers 61 and 62 have
Arm portions 61b and 62b are formed for blocking or PAUSE in the _T1 mode.

Although the pinch roller levers 60, 61 and the capstans 69, 70 are shown with separate reference numerals for convenience in the description of this embodiment, they are actually coaxial.

The sub chassis 76 has a long hole 7 provided therein.
6b and the pin 76a that engages with it, C, D
The spring 77 is configured to be slidable in the direction.
is biased in the C direction. A pinch operation lever 78 is attached to the shaft 76c of the sub chassis 76.
Another pinch operation lever 79 is rotatably attached to another shaft 76d. The pinch operation levers 78, 79 have hit pins 78a, 79.
a is formed, and end surfaces 46h and 46i of the program switching lever 46 are always connected by springs 80 and 81.
is energized by The pause lever 82, which is configured to be slidable in the C and D directions, is urged in the D direction by a spring 83 and is prevented from moving in the D direction by a pin 76e of the sub-chassis 76. The pause back lever 82 includes arm portions 82a and 82b for releasing the locking of the sensor killers 84 and 85, arm portions 82c and 82d for pushing down the pinch roller levers 61 and 62 during pause, and arm portions 82c and 82d for pushing down the pinch roller levers 61 and 62 in the D direction. A convex portion 92f is formed to prevent the slide. The sensor killers 84 and 85 have shafts 84a and 85a, respectively.
The sensor lever 2 on the T 2 side is attached rotatably with the T ₂ side sensor lever 2 attached as a fulcrum, and the rotational force in the E direction is applied by the springs 86 and 87.
The arms 28c and 28d at both ends of the 8 are pressed.

The mode select lever 30 has a trapezoidal convex portion 30k formed at a position facing the arm portion 60b of the _T1 side pinch roller lever 60, and regulates the operation of the pinch roller lever 60 according to each mode. Furthermore, the arm portions 30l, 30m, and 30n formed on the mode select lever 30 are connected to the sensor killer 8.
4, 85 is disengaged. Another sensor killer 88 is rotatably attached around a shaft 88a, and a spring 89 applies a rotational force in the E direction to the arm portion 3 of the mode select lever 30.
0 m, but is not pressed against the arm portion 19c of the _T1 side sensor lever 19. On the other hand, the arm portion 19d of the sensor lever 19 has a shaft 90a.
A sensor killer 90 is mounted rotatably around the fulcrum and is pressed by a spring 91 to which a rotational force in the E direction is applied.

Further, a slide lever 92 that is slidable in directions A and B is abutted on one end side surface 30o of the mode select lever 30 by a spring (not shown). A blocking lever 93 is rotatably attached to a shaft 92a formed on the slide lever 92. This blocking lever 93 is given a rotational force in the F direction by a spring (not shown), but is locked by the abutment pin 92b of the slide lever 92 and prevented from rotating in the F direction. At a position facing the arm portion 93a of the blocking lever 93,
A connecting lever 94 that is slidable in directions A and B is attached, and a pin 94a formed on this connecting lever 94 is in contact with an inclined surface 53b formed on the REC lever 53. REW lever 55
At the tip of the FF lever 56, there is an F/R interlocking lever 95 that can slide in the C and D directions.
6 in the C direction. When FF or
During REW, the pins 95a and 95b formed on the F/R interlocking lever 95 are slid in the D direction and press the sensor killers 90 and 85, respectively.

Next, the operating state of this embodiment will be explained for each mode based on the drawings.

(1) Edit mode time In the tape recorder according to one embodiment of the present invention, two operating states can be selected after selecting the edit mode. That is, there are two states: a playback state only on the _T1 side, and a so-called dubbing state in which playback is performed on the _T1 side and recording is performed on the _T2 side. First, the selection of the playback state only on the _T1 side will be explained.

(1-1) Figure 11 shows the _T1 playback state in the edit mode. Stopped state (10th
When only the PLAY lever 54 is pressed in the D direction from the figure), the sub-chassis 76 is pressed in the same direction. At this time, the pin 54a formed on the PLAY lever 54 touches the protrusion 59 of the lock plate 59.
b, and the operating state is maintained. At the same time, pinch operation levers 78 and 79 attached to the sub-chassis 76 are also slid in the D direction. The pinch operation lever 78 contacts and presses a spring 72 attached to the _T1 side pinch roller lever 60, whereby the pinch roller lever 60 is rotated in the F direction about the shaft 63 as a fulcrum. The arm portion 60b of the pinch roller lever 60 rotates without being restricted by the convex portion 30k of the mode select lever 30, and the roller portion 60a is pressed against the capstan 69. On the other hand, sub chassis 76
As the spring 83 slides in the D direction,
The pose buckle lever 82 is slid in the D direction by the convex portion 82f of the pause lever 82
It comes into contact with and stops the slide. Therefore, the pinch roller lever 6 on the _T2 side is rotated in the F direction with the spring 73 pressed by the pinch operation lever 78 and the shaft 64 as a fulcrum.
1, the arm portion 61b has a pose back lever 82.
The rotation of the roller portion 61a is regulated by contacting the arm portion 82c of the capstan 70.
Do not crimp. Further, in the REV side pinch roller lever 62, the pinch operation lever 79 contacts the spring 74, but does not press it, and the roller portion 62a does not press against the capstan 71. Similarly, play idlers, circuits, etc. (not shown) operate, and only the _T1 side is in the playback state.

Next, the auto-stop sensor in this state will be explained.

The end detection sensor killers of the tape recorder are two sensor killers 88 and 90 on the _T1 side sensor lever 19, and a sensor killer 8 on the _T2 side sensor lever 28.
4 and 85 are designed to act respectively.

First, the sensor killer 88 is pressed by the arm 30m of the mode select lever 30, and the arm 19c of the _T1 side sensor lever 19
The pressure on has been released. The sensor killer 90 is also pressed against the tip 76g of the sub chassis 76 during operation, and the sensor lever 1
The pressure on the arm portion 19c of No. 9 has been released.
The sensor killer 90 is also pressed against the tip 76g of the sub-chassis 76 during operation, and the pressure on the arm 19d of the sensor lever 19 is released. Therefore, at the end of tape winding, as the take-up reel cap and reel stand stop rotating, the sliding protrusion 19b of the sensor lever 19 is pressed to the maximum diameter of the swing cam 20a, then stops once, and the cam stops rotating. 20c outer surface 2
0b to start the end detection operation.
On the other hand, the arm portion 28c of the _T2 side sensor lever 28
A sensor killer 84 is pressed against the arm portion 28d, and a sensor killer 85 is pressed against the arm portion 28d, so that the sliding protrusion 28b of the sensor lever 28 is always disposed around the swing cam 20a. Therefore, even if the rotation of the take-up reel stand is stopped, the same sliding movement as when it is in operation is performed, so that the end detection operation is not performed.

Next, the selection of the dubbing state will be explained.

(1-2) Figure 12 shows the dubbing state in the edit mode. Stopped state (10th
(Figure) to PLAY lever 54 and REC lever 5
3 and press in the D direction. sub chassis 76
is slid in the D direction as described above, and the roller portion 60a of the _T1 side pinch roller lever 60 is pressed against the capster 69. On the other hand, REC
As the lever 53 is pressed, the pin 94a of the connecting lever 94 that was in contact with the inclined surface 53b is pressed, causing the connecting lever 94 to slide in the direction B and pressing the arm portion 93a of the blocking lever 93. The blocking lever 93 is rotated in the E direction using the shaft 92b as a fulcrum. Sub chassis 76 D
The pause lever 82, which is slid in the D direction by the spring 83, slides without the convex portion 82f being engaged with the blocking lever 93 and is locked to the pin 76e of the sub-chassis 76. The _T2 side pinch roller lever 61 is rotated in the F direction without the arm portion 61b coming into contact with the arm portion 82c of the pose back lever 82, and the roller portion 61a
is crimped onto the capstan 70. However, in the pinch roller lever 62, although the pinch operation lever 79 comes into contact with the spring 74, it does not press the spring 74, and the roller portion 62a
1 is not crimped. Similarly, play idlers and circuits not shown operate, so
It becomes a dubbing state where you play on T ₁ and record on T ₂ at the same time.

Next, the killer of the end detection sensor in this state will be explained.

The sensor killer 90 is pressed by the tip 76g when the sub-chassis 76 slides, and the pressure on the arm 19d of the sensor lever 19 is released. Also, as the pose back lever 82 slides in the D direction, the sensor killer 84
is attached to the arm part 82a of the pose back lever 82,
The sensor killers 85 are pressed by the arm portions 82b, and the sensor killers 85 are pressed by the arm portions 82b of the sensor lever 28.
The pressure on c and 28d is released. Also, in the sensor killer 88, when the editing mode is selected, the pressure on the arm portion 19c of the sensor lever 29 is released, so the four sensor killers 84, 85, 88, and 90 all press the sensor levers 19, 28. has been canceled. Therefore, the winding end of the tape is reached first on the _T1 side or the _T2 side, and the end detection operation is started when the take-up reel cap or reel stand stops rotating.

FIG. 4 shows the mechanical configuration in the editing mode. As shown above, the tape reaches the end,
Sensor lever 19 or sensor lever 2
8 rotates in the E direction around the shafts 18a and 18b, respectively, the pin 32c or 3 formed on the end select lever 32
2d and slide the end select lever 32 in the D direction. Therefore, the convex portion 32b of the end select lever 32 slides the lock plate release lever 33 in the D direction. Along with this, pin 3 of the lock plate release lever 33
3c presses the inclined surface 59f of the lock plate 59 and slides the lock plate 59 in the direction A, so that the pin 54a of the PLAY lever 54 and
The pin 53a of the REC lever 53 is disengaged from the lock plate 59 and is in a stopped state (see FIG. 12).

Next, I will explain the sensor killer in the pause state. Note that the pause function in the tape recorder in one embodiment of the present invention is designed to work only on the _T2 side. First of all, the pose movement is
In the operating state shown in Figure 12, PAUSE
Press the lever 58 in the D direction. The PAUSE lever 58 is the arm 7 of the PAUSE operation lever 75.
Press 5b, so PAUSE operation lever 7
5 is rotated in the E direction about the shaft 75a, presses the end surface 82e of the pose back lever 82 that is in contact with the arm 75c, and slides the pose back lever 82 in the C direction.
The arm portion 82c of the pose back lever 82 is
Arm portion 61b of _T2 side pinch roller lever 61
and press the roller part 61a and capstan 7.
Release the pressure bond with 0. Also, since the play idler (not shown) is also released from crimping, T ₁
The operation will only occur. Furthermore, since the arm portions 82a and 82b of the pose buckle lever 82 are released from pressing against the sensor killers 84 and 85, each sensor killer 84 and 85 is
6 and 87, and is pressed against the arm portions 28c and 28d of the _T2 side sensor lever 28. Therefore, the state is the same as the _T1 regeneration state, and the _T2 side sensor lever 28 is killed.

Next, I will explain the sensor killer during FF or REW. In the tape recorder according to one embodiment of the present invention, FF or REW operates on the _T1 side when editing mode is selected. From the stopped state shown in Figure 10
When the FF lever 56 or the REW lever 55 is pressed in the D direction, the F/R interlock lever 95 moves to the D direction.
be slid in the direction. F/R interlock lever 9
5 pins 95a and 95b are sensor killer 9
Press 0,85 and sensor lever 29,2
Release the pressure on 8. However, since the sensor killer 84 is pressed against the arm portion 28c of the _T2 side sensor lever 28, the sensor lever 28 is killed. On the other hand, when the sensor killer 88 is selected, the pressure on the sensor lever 19 is released, so when the tape reaches the end in FF or REW and the take-up reel cap and reel stand stop rotating, the sensor killer 88 will end the tape in the same way as during playback. The detection operation will begin.

(2) In continuous mode at T ₂ Figure 13 shows FOR in continuous mode at T ₂
Indicates operating status. The positioning pin 30c of the mode select lever 30 is connected to the mode setting plate 31.
is engaged with the recess 31b. From a stopped state
When the PLAY lever 54 is pressed in the D direction, the sub-chassis 76 is pressed in the same direction. The pin 54a formed on the PLAY lever 54 is connected to the rotation plate 59.
The operating state is maintained by being locked by the convex portion 59b. At the same time, pinch operation levers 78 and 79 attached to the sub-chassis 76 also slide in the D direction. The pinch operation lever 78 contacts and presses a spring 72 attached to the _T1 side pinch roller lever 60, whereby the pinch roller lever 60 is rotated in the F direction about the shaft 63 as a fulcrum. However, pinch roller lever 6
The arm portion 60b of 0 contacts the convex portion 30k of the mode select lever 30, and rotation in the F direction is restricted, so the roller portion 60a does not press against the capstan 69. On the other hand, when the continuous mode is selected at _T2 , the slide lever 92 comes into contact with the recess 30p of the mode select lever 30, so that it slides in the B direction compared to the editing mode. Furthermore, since the blocking lever 93 is also sliding in the B direction as the select lever 30 slides, the pause lever 82 is sliding in the D direction without the convex portion 82f being engaged with the blocking lever 93. The pinch roller lever 61 is rotated in the direction F using the shaft 64 as a fulcrum with the spring 73 pressed by the pinch operation lever 78, so that the arm portion 61b of the arm portion 82c of the back lever 82 is in a pose position.
The roller portion 61a is rotated without contacting the roller portion 61a.
is crimped onto the capstan 70. However, although the pinch operation lever 79 of the pinch roller lever 62 comes into contact with the spring 74, it does not press the spring 74, and the roller portion 62a is not pressed against the capstan 71. Similarly, play idlers, circuits, etc. (not shown) operate, resulting in the FOR operation state on the _T2 side.

Next, the switching operation from FOR to REW and
Explain the operating status of REW. FIG. 5 shows the mechanical configuration of the FOR state in continuous mode at _T2 . When the end of the tape winding is reached in this state, the sensor lever 28 is rotated in the E direction by the end cam 20 with the shaft 18b serving as a fulcrum. Pin 32 formed on sensor lever 32
Press d in direction D to release end select lever 3.
2 in the same direction. At this time, the convex portion 32b of the end select lever 32 is not in a position to engage with the pin 33a of the lock plate release lever 33, and the lock plate release lever 33 is not operated. On the other hand, since the pin 32e formed on the end select lever 32 presses the arm 34a of the trigger lever 34, the trigger lever 34 is rotated in the E direction about the shaft 34b, and the protrusion formed on the logic cam gear 35 Section 35a
disengaged from the logic cam gear 3
5 is rotated in the E direction by a starting spring (not shown) and meshes with the gear 38, and the cam 36
It is also rotated in the E direction. The pin 39a of the program interlocking lever 39 contacts the convex portion 30f of the mode select lever 30, and the pin 39c of the program interlocking lever 39 is positioned so as to slide on the inside 36a of the cam 36 when the logic cam gear 35 rotates. Therefore, as the logic cam gear 35 rotates, the pin 39c of the program interlocking lever 39 moves inside the cam 36.
is pressed, and the program interlocking lever 39 is slid in the B direction. Therefore, the pin 39d formed on the program interlocking lever 39 presses the arm portion 41a of the cam lock lever 41, so the cam lock lever 41 rotates the shaft 41b to the F position.
The program switching cam gear 4
The engagement with the protrusion 42a formed at 2 is released. Therefore, the program switching cam gear 4
2 is F by a starting spring (not shown).
It is rotated in the F direction and meshes with the gear 43, and is rotated together with the program switching cam 45 in the F direction. Accordingly, the program switching lever 46 that is in contact with the program switching cam 45 is slid in the direction B by the spring 47. At this time, the program switch attached to the program switching lever 46
The RVS lever 48 is the end select lever 3
2 so that the pin 32f formed at 2 is not pressed.

FIG. 14 shows the operating state of REV.
When the program switching lever 46 slides in the B direction, the pinch operation lever 79 is biased by the left inner end surface 46i of the program switching lever 46.
The contact pin 79a is pressed in the same direction, and the shaft 76
It is rotated in the E direction using b as a fulcrum. The pinch action lever 79 presses a spring 74 attached to the pinch roller lever 62. The pinch roller lever 62 is rotated in the E direction about the shaft 65, and the roller portion 62a is pressed against the capstan 71. On the other hand, pinch operation lever 78
As the program switching lever 46 slides in the B direction, it is rotated by the spring 80 in the E direction about the shaft 76c, releasing the pressure on the spring 73 attached to the pinch roller lever 61, so that the roller portion 61a The pressure bonding to the capstan 70 is released. At the same time, play idlers and circuits (not shown) operate,
It enters REV operating state.

FIG. 6 shows the mechanism configuration in the REV state.
When the tape ends in this state, the end select lever 32 is slid in the D direction as described above, but the protrusion 32b is connected to the lock plate release lever 3.
3 does not operate. On the other hand, the pin 32e presses the trigger lever 34 and the logic cam gear 35
Rotate. The pin 39c of the program interlocking lever 39 slides on the inner side 36a of the cam 36 and is pressed.
9 is slid in the B direction to release the engagement between the cam lock lever 41 and the program switching cam gear 42. Therefore, since the program switching cam gear 42 is rotated in the F direction, the program switching lever 46 is pushed in the A direction. As the program lever 46 slides, the pinch operation levers 78 and 79 are rotated to press the roller portion 61a of the FOR side pinch roller lever 61 to the capstan 70, and also to press the roller portion 62a of the REV side pinch roller lever 62 and the capstan 71. The crimp is released and the operation is switched to the FOR operation shown in FIG. 13 described above.

As mentioned above, in continuous mode at T ₂ ,
After the FOR and REV operations, the end select lever 32 is slid by rotation of the sensor lever 28, the logic cam gear 35 is rotated, the program switching cam gear 42 is rotated via the program interlocking lever 39, and the program switching lever 46 is rotated. Slide it. By switching the pin operating levers 78 and 79,
Perform continuous playback of FOR and REV.

Next, the killer of the termination detection sensor in this mode will be explained.

FIG. 13 shows the operating state in one cycle mode at _T2 . When this mode is set with the mode select lever 30, the sensor killer 84 is pressed by the arm 30n of the mode select lever 30 and is rotated in the direction F using the shaft 84a as a fulcrum. The pressure is released. On the other hand, the sensor killer 88 does not press the arm portions 30l, 30m of the mode select lever 30, but presses the arm portion 19c of the sensor lever 19. During operation, the sensor killer 20 is connected to the sub chassis 7.
At the tip 76g of the sensor killer 85, the pressure on the sensor levers 19 and 28, respectively, is released by the adjacent portion 82b of the pause lever 82. Therefore, T ₁ side sensor lever 19
This means that the _T2 side sensor lever 28 has been killed. Therefore, at the end of winding the tape, as the take-up reel stand stops rotating, the sensor lever 28 is rotated, slides the end select lever 32, and starts the switching operation.

Next, I will explain the sensor killer in the pause state. As before, press the PAUSE lever 58 in the D direction and slide the PAUSE back lever 82 in the C direction to enter the pause state. Since the arm portion 82b of the pose back lever 82 is released from pressing against the sensor killer 85, the sensor killer 85
is rotated in the E direction by the spring 87 about the shaft 85a, but the sensor lever 2
Since the arm portion 28d of No. 8 is pressed, the switching operation does not start during the pause. Also FF
Alternatively, during REW, the sensor killers 90 and 85 are released from being pressed against the sensor levers 19 and 28 by the F/R interlocking lever 95, as in the operation. Further, the sensor killer 84 is released from being pressed against the arm 28c of the sensor lever 28, and the sensor killer 88 is released from the sensor lever 19.
is pressed by the arm portion 19c. Therefore, the _T1 side sensor lever 19 is locked, and the _T2 side sensor lever 28 is turned off. Therefore, at the end of winding the FF or REW tape, the sensor lever 28 rotates as the take-up reel stand stops rotating, and the end select lever 32 slides in the D direction.
Although not shown, when the FF or REW lever is pressed in _T2 mode, the end select lever 32 is pressed in the E direction, and the protrusion 32
Since the lock plate release lever 33 is rotated to a position opposite to the pin 33a of the lock plate release lever 33, when the end select lever 32 slides, the lock plate release lever 33 is slid and comes to a stopped state.

(3) In 1-cycle mode at T ₂ Figure 15 shows the FOR operation state in 1-cycle mode at T ₂ . The positioning pin 30c of the mode select lever 30 is engaged with the recess 31c of the mode setting plate 31. When the PLAY lever 54 is pressed in the D direction from the stopped state, the sub-chassis 76 is pressed in the same direction. At the same time, the pinch operation levers 78 and 79 are also slid in the D direction, and the pinch operation lever 78 presses the spring 72 attached to the _T1 side pinch roller lever 60, causing the pinch roller lever 60 to move to F.
direction. However, the arm portion 60b of the pinch roller lever 60 is connected to the mode select lever 30.
The roller portion 60a does not press against the capstan 69 because the roller portion 60a comes into contact with the convex portion 30k and rotation in the F direction is restricted. On the other hand, when the 1 cycle mode is selected at _T2 , the slide lever 92 comes into contact with the recess 30p of the mode select lever 30.
It is slid in the B direction as in the continuous mode at _T2 . Further, since the blocking lever 93 is also slid in the B direction, the pull lever 82 is slid in the D direction without the convex portion 82f being engaged with the blocking lever 93. The spring 73 is pressed against the pinch operation lever 78, and the pinch roller lever 6 is rotated in the F direction.
1, the arm portion 61b rotates without contacting the arm portion 82c of the pause lever 82, and the roller portion 61a is pressed against the capstan 70. However, in the pinch roller lever 62, the pinch operation lever 79 comes into contact with the spring 74, but does not press it, and the roller portion 62a is moved against the capstan 71.
is not crimped. Similarly, play idlers and circuits (not shown) operate, and the FOR on the _T2 side
It becomes operational.

Next, the switching operation from FOR to REV and REV
Explain the operating status of. FIG. 7 shows the mechanical configuration of the FOR state in the 1-cycle mode at _T2 . When the end of tape winding is reached in this state, the end select lever 32 is slid in the D direction, presses the trigger lever 34, and rotates the logic cam gear 35, as in the continuous mode at _T2 . The pin 39c of the program interlocking lever 39 is located on the inside 36a of the cam 36.
is slid in direction B, and presses the cam lock lever 41. Therefore, the program switching cam gear 42 is rotated in the F direction, and the program switching lever 46 is slid in the B direction. At this time, the pin 30 of the mode select lever 30 is attached to the program switching lever 46.
The RVS lever 48 positioned by h is also B
A pin 3 formed on the end select lever 32 that is slid in the direction and faces the slide direction.
2f, and the pin 33 of the lock plate release lever 33 contacts the convex portion 32b of the end select lever 32.
Press it to the position where it engages with a. As in the continuous mode at T ₂ , the pinch operation levers 78 and 79 are rotated as the program switching lever 46 slides to release the pressure between the roller portion 61a of the FOR side pinch roller lever 61 and the capstan 70, and the REV side pinch roller Lever 6
The second roller portion 62a is pressed onto the capstan 71. The play idler also switches the circuit etc.
T ₂ side REV operation status.

Figure 8 shows the mechanism configuration in the REV state.
When the tape ends in this state, the end select lever 32 is slid in the D direction as described above. For this reason, the end select lever 3
2 presses the pin 33a of the lock plate release lever 33, slides the lock plate release lever 33 in the D direction, and releases the engagement between the lock plate 59 and the PLAY lever 54. to stop the operation.

As mentioned above, in the 1 cycle mode at _T2 , when switching from FOR to REV, the RVS lever 48 attached to the program switching lever 46
Press the end select lever 32 with
After the operation, as the end select lever 32 slides, the lock plate release lever 33 is slid to a stopped state.

Next, the killer of the termination detection sensor in this mode will be explained.

FIG. 15 shows the operating state in one cycle mode at _T2 . When this mode is set with the mode select lever 30, the sensor killer 84 is pressed by _the arm 30n of the mode select lever 30, and the pressure on the arm 28c of the sensor lever 28 is released, as in the continuous mode at T2. ing. On the other hand, sensor killer 88
are the arms 30l, 3 of the mode select lever 30.
0m, but is pressed by the arm portion 19c of the sensor lever 19. During operation, each sensor killer 9 is the same as described above.
0 and 85 are sensor levers 19 and 28 respectively
The pressure on is released. Therefore, since the T ₁ side sensor lever 19 is locked and the T ₂ side sensor lever 28 is turned off, the sensor lever 28 is rotated and the switching operation is started at the end of the tape winding. Also, the sensor killer in the pause state, FF or REW state is the same as in the continuous mode in _T2 described above, so the explanation will be omitted.

(4) In continuous mode Figure 9 shows the operating status in continuous mode. The positioning pin 30c of the mode select lever 30 is engaged with the recess 31d of the mode setting plate 31. Further, the slide lever 92 is in contact with the end surface 30o of the mode select lever 30. When the PLAY lever 54 is pressed in the D direction from the stopped state, the sub-chassis 76 is slid in the same direction. The pinch operation lever 78 presses a spring 72 attached to the _T1 side pinch roller lever 60, and rotates the pinch roller lever 60 in the F direction. pinch roller lever 60
The arm portion 60b is rotated without being restricted by the convex portion 30k of the mode select lever 30,
The roller portion 60a is pressed against the kipstane 69. On the other hand, as the sub chassis 76 slides,
The pause lever 82, which is slid in the D direction by the spring 83, is stopped from sliding when the convex portion 82f comes into contact with the blocking lever 93.
Therefore, the rotation of the _T2 side pinch roller lever 61, which is rotated in the F direction by the spring 73 being pressed by the pinch operation lever 78, is restricted by the arm portion 61b coming into contact with the arm portion 82c of the pause lever 82. , the roller portion 61a is not pressed against the capstan 70. Further, in the REV side pinch roller lever 62, the pinch operation lever 79 contacts the spring 74, but does not press it, and the roller portion 62a does not press against the capstan 71. At the same time, the play idler circuit (not shown) operates, and the _T1 side enters the playback state.

Next, the switching operation from T ₁ to T ₂ will be explained. FIG. 9 shows the mechanical configuration in continuous mode. When the end of the tape winding is reached in this state, the end select lever 32 is slid in the D direction as described above, but the convex portion 32b does not press the pin 33a of the lock plate release lever 33. On the other hand, the pin 32e presses the trigger lever 34 and rotates the logic cam gear 35. The cam 37 formed in the logic cam gear 34 connects the built-up portion 30e of the mode select lever 30 to T ₂
Press to the position opposite to the 1 cycle mode. That is, the positioning pin 30c of the mode select lever 30 is slid from the protrusion 31d of the mode setting plate 31 to the protrusion 31c. As described above, the convex portion 30k of the slid mode select lever 30 presses the arm portion 60b of the _T1 side pinch roller lever 60 to release the pressure bond between the roller portion 60a and the capstan 69. On the other hand, the slide lever 92 comes into contact with the convex portion 30p of the mode select lever 30, thereby allowing the blocking lever 93 and the pause lever 82 to
The engagement with the convex portion 82f is released. Therefore
The arm portion 61b of the _T2 side pinch roller lever 61 is
Since the pose buckle lever 82 is no longer restricted by the arm portion 82c and rotates in the F direction, the roller portion 61a is pressed against the capstan 70. Note that when the logic cam gear 35 rotates, the pin 39c of the program interlock lever 39 passes outside the cam 36, so the program interlock lever 39 does not slide. In addition, play idlers and circuits (not shown) operate, and the above-mentioned (Fig. 15)
The FOR state is in one cycle mode at T ₂ . Thereafter, it switches to REV at the end of FOR tape winding, and stops at the end of REW winding.

Next, the killer of the termination detection sensor in this mode will be explained.

FIG. 16 shows the operating state in continuous mode. When this mode is set using the mode select lever 30, the sensor killer 88 is pressed by the arm portion 30l of the mode select lever 30, and the press against the arm portion 19c of the sensor lever 19 is released. Further, the sensor killer 90 is also pressed against the tip 76g of the sub-chassis 76 during operation, and the pressure on the arm 19d of the sensor lever 29 is released. Therefore, at the end of tape winding, the switching operation is started as the take-up reel cap and reel stand stop rotating. On the other hand, a sensor killer 84 is pressed against the arm 28c of the sensor lever 28, and a sensor killer 85 is pressed against the arm 28d of the sensor lever 28, so that the same sliding motion as in operation is applied regardless of the rotation of the take-up reel stand. Therefore, no switching operation is performed.

Next, I will explain the sensor killer during FF or REW. In addition, in the tape recorder in one embodiment of the present invention, when continuous mode is selected, FF
Or REW is set to work on the _T1 side. When the FF lever 56 or REW lever 55 is pressed in the D direction from the stopped state, the F/R interlocking lever 95 is slid in the same direction, and the pin 95a
and pin 95b press sensor killers 90 and 85, respectively, and release the pressure on sensor levers 19 and 28. However, since the sensor killer 84 is pressed against the arm 28c of the _T2 side sensor lever 28, the sensor lever 28 is killed. On the other hand, the sensor killer 88 is released from being pressed against the sensor lever 19 when the mode is selected. Note that when the FF lever 56 or the REW lever 55 is pressed, the end select lever 32 is pressed in the E direction and the convex portion 32d is rotated to a position opposite to the pin 33a of the lock plate release lever 33. At the end of winding the REW, when the end select lever 32 slides, the lock plate release lever 33 slides and comes to a stopped state.

(G) Effects of the Invention According to this invention, when each tape mode position is selectively taken by the mode select lever means, the blocking means for disabling the operation of the first and second end detection sensor means is stopped. Since the end detecting operation is prevented on the reel cap or reel stand on the side where the tape is moved, malfunction of each end detecting sensor during operation can be eliminated, and the first or second tape operation can be performed correctly.

[Brief explanation of the drawing]

Figures 1 to 16 are drawings showing one embodiment of the present invention, with Figure 1 being a vertical sectional view of the main parts showing the arrangement when the cassette tape is installed, and Figure 2 being a front view showing the operation button part. Figures 3a and 3b are a longitudinal sectional view and a plan view of the main parts showing the auto-stop sensor section, and Figures 4 to 9 show the mechanism configuration. Figure 5 shows the FOR state in continuous mode at T ₂ , Figure 6 shows the REV state in continuous mode at T ₂ , Figure 7 shows the FOR state in 1 cycle mode at T ₂ , and Figure 8 shows the 1 at T _2. REV status in cycle mode, 9th
The figure shows the switching mechanism of the sensor killer and pinch roller in continuous mode, Figures 10 to 16 show the switching mechanism of the sensor killer and pinch roller, Figure 10 shows the stopped state in continuous mode, and Figure 11 shows T ₁ in edit mode. Playback status, Figure 12 is dubbing status in edit mode, Figure 13 is FOR in continuous mode at T ₂
Figure 14 shows the REV reproduction status in continuous mode at T ₂ , Figure 15 shows the FOR reproduction status in 1 cycle mode at T ₂ , and Figure 16 shows the reproduction status in continuous mode. . 1, 2... Cassette tape, 3, 4... Capstan, 6, 7, 8... Pinch roller, 15...
End detection sensor, 25... Auto stop sensor, 30... Mode select lever, 54...
PLAY lever, 84, 85, 88, 90...sensor killer.

Claims (1)

[Claims] 1. Two cassette tapes, the first and second, are
These cassette tapes are stacked and stored in two tape storage units, and one capstan shaft is made to correspond to these cassette tapes, and the first and second cassette tapes are
In a duplex tape recorder that selectively runs the first and second cassette tapes at a constant speed by abutting the first and second pinch rollers corresponding to the respective cassette tapes, the tape recorder moves from a non-operating position to an operating position. a play lever means for bringing a first or second pinch roller into contact with the capstan shaft when the tape is pressed; a play lever means capable of selectively taking a first and second tape mode position; a mode select lever means which cooperates with the means to control contact of the first or second pinch roller with the capstan shaft according to each mode; and a mode select lever means which controls the end of the tape by rotating the reel cap on which the first cassette tape is mounted. a first end detection sensor means for detecting the end of the tape; a second end detection sensor means for detecting the end of the tape by rotation of a reel stand on which a second cassette tape is mounted; and a mode select lever means for determining each tape mode position. blocking means acting on each of the end detection sensor means to disable the action of each of the end detection sensor means, when the mode select lever means assumes the first or second tape mode position, each tape A blocking mechanism for an end detection sensor of a duplex tape recorder, characterized in that the blocking means acts on the end detection sensor means on the non-running tape mode side depending on the mode, thereby disabling the end detection function thereof.