JPH0668542A - Condensation detector for vtr - Google Patents

Abstract

PURPOSE:To evade a damage to a tape by inhibiting the loading operation when condensation takes place in a tape cassette even if no condensation is caused on a head drum. CONSTITUTION:A condensation sensor 23 is arranged at a position facing an insertion path of a tape cassette TC in the inside of a VTR main body in a state of in slide contact onto a side face of the tape cassette TC. The condensation sensor 23 is fitted to a free end of a sensor mount lever 22 energized toward the cassette insertion path with a spiral spring 24 supported by a support shaft 21 and connected to a control circuit 5 via a lead wire 17. When the resistance of the condensation sensor 23 is increased due to depositted drops and the sensor 23 outputs a drop detection signal, the control circuit 5 inhibits the loading operation of the video tape 16 to the head drum 2 even in the presence of recording/reproduction command.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dew condensation detecting device in a VTR (video tape recorder).

[0002]

2. Description of the Related Art When a video tape is loaded on a head drum or a video tape of a VTR and is rotated at a relatively high speed while the dew condensation is generated on the head drum, the video tape is transferred to the peripheral surface of the head drum through dew drops. May stick to the tape and damage the tape. Therefore, measures are taken such that a dew condensation sensor is provided to detect the presence or absence of dew condensation and prohibit the loading of the video tape onto the head drum when dew condensation occurs.

FIG. 2 shows a conventional VT having a dew condensation detecting device.
It is a schematic plan view which shows the cassette loading part of R. In the figure, 1 is a chassis, 2 is a head drum, 3 is a tape loading mechanism, 4 is a condensation sensor, 5 is a control circuit, and T
C is a tape cassette.

The outline of the tape loading mechanism 3 is as follows. A TU pole base 8 to which the guide roller 6 and the inclined pole 7 are attached is configured to be slidable in the long hole 9, and the guide roller 10 and the inclined pole 11 are also provided.
The SU pole base 12 to which the and are attached is configured to be slidable in the long hole 13. A is head drum 2
Rotation direction (during normal playback), B is loading direction, C
Is the unloading direction, and D is the insertion direction of the tape cassette TC. 14 is a supply reel, 15 is a take-up reel,
16 is a video tape. Condensation sensor 4 is chassis 1
And is connected to the control circuit 5 via a lead wire 17. The dew condensation sensor 4 is configured so that its resistance value increases when dew drops adhere to its surface.

Next, the operation will be described. Tape cassette T
When C is inserted into the cassette loading portion of the VTR, the tape cassette TC once moves to the back side and then moves to the lower side to be set at the reference height. At this time, the pole bases 8 and 12 enter the inside of the video tape 16. When a recording operation or a reproduction operation command is given to the control circuit 5 by pressing the recording button or the reproduction button on the operation panel, the control circuit 5 reads the state of the dew condensation sensor 4. If the dew condensation sensor 4 does not detect dew drops and the resistance value is a low standard value, the control circuit 5
Gives a loading instruction to the tape loading mechanism 3. As a result, the pole bases 8 and 12 are formed into the long holes 9 and 13.
In the B direction, and move the videotape 16 to the head drum 2
It will be wound around the peripheral surface of and recorded or reproduced.

When the atmosphere in the room in which the VTR is installed becomes humid, dew condensation occurs on the head drum 2. When the head drum 2 is condensed, the condensation sensor 4 is also condensed. Further, even when the VTR is carried from a low temperature room to a high humidity room, dew condensation occurs on the head drum 2 due to rapid cooling of water vapor in the atmosphere, and dew condensation also occurs on the dew condensation sensor 4 almost at the same time. In this way, when the dew condensation sensor 4 detects a dew drop and the resistance value thereof is higher than the reference value, the control circuit 5 will not operate even if a command for recording operation or reproduction operation is given to the control circuit 5. When the state of the dew condensation sensor 4 is read, it is determined that dew condensation has occurred based on the input of the dew drop detection signal (increased resistance value), and the operation of the tape loading mechanism 3 is prohibited. As a result, it is possible to avoid the tape damage caused by the video tape 16 sticking to the head drum 2 via the dew drop.

[0007]

In the above-described conventional dew condensation detecting device in the VTR in which the dew condensation sensor 4 is attached to the chassis 1, even if the dew condensation sensor 4 can detect the presence or absence of dew condensation on the head drum 2, it does not affect the tape cassette TC. The presence or absence of condensation could not be directly detected. That is, since the dew condensation sensor 4 is permanently provided on the chassis 1 (VTR main body) together with the head drum 2, the dew drop adhesion to the dew condensation sensor 4 can be regarded as the dew drop adhesion to the head drum 2. You can

However, the tape cassette TC is always a VTR.
It does not exist integrally with the main body, but is frequently attached and detached. Therefore, a difference naturally occurs between the dew condensation state of the VTR body and the dew condensation state of the tape cassette. In particular, when a tape cassette is carried from a low temperature room to a humid room, water vapor in the atmosphere is cooled and condensed by the low temperature tape cassette, and dew condensation occurs on the surface of the tape cassette and the video tape inside. At this time, it is assumed that dew condensation has not occurred on the VTR main body and the resistance value of the dew condensation sensor 4 is also a low reference value. When the tape cassette with dew condensation as described above is loaded into such a VTR main body, the detection state of the dew condensation sensor 4 does not change, so that even if the control circuit 5 reads the state of the dew condensation sensor 4 at the time of loading. There is a risk that the video tape 16 to which dew droplets are attached will adhere to the peripheral surface of the head drum 2 without prohibiting the loading operation, and the video tape 16 may be damaged.

The present invention was devised in view of such circumstances, and in a state in which no dew condensation has occurred in the VTR main body, a tape cassette with dew condensation is loaded and tape loading onto the head drum is performed. It is intended to prevent the tape damage by prohibiting the loading operation even when the command is issued.

[0010]

SUMMARY OF THE INVENTION The present invention is a dew condensation detecting device in a VTR having a control circuit for prohibiting a loading operation of a video tape onto a head drum when a dew condensation sensor detects dew condensation. It is characterized in that the dew condensation sensor is arranged in a state of being brought into contact with the tape cassette in a position facing the insertion path or the loading position of the tape cassette inside the VTR main body.

The dew condensation sensor may come into contact with the tape cassette at any time between the time when the tape cassette is inserted and the time when the tape cassette is completely loaded on the head drum, but it is preferable that the dew condensation state be set as early as possible. It is better to insert the cassette for the purpose of detection.

[0012]

The dew condensation sensor can detect the dew condensation state of the inside of the VTR, that is, the head drum, as well as the dew condensation state of the tape cassette by directly contacting the dew condensation sensor with the tape cassette. You can Therefore, even if dewdrops are not attached to the VTR main body and then to the head drum, if dewdrops are attached to the newly inserted tape cassette,
The dew condensation sensor that contacts the tape cassette detects the dew drop and sends a dew drop detection signal to the control circuit, so that the loading operation of the video tape onto the head drum is prohibited.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a dew condensation detecting device in a VTR according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic plan view showing a cassette loading portion of a VTR having a dew condensation detecting device according to an embodiment of the present invention. In FIG. 1, the same reference numerals as those in FIG. 2 according to the conventional example indicate the same parts or the same parts in this embodiment. That is, 1 is a chassis, 2 is a head drum, 3 is a tape loading mechanism, 8 is a TU pole base to which a guide roller 6 and an inclined pole 7 are attached, and 9
Is a long hole, 12 is a SU pole base on which the guide roller 10 and the inclined pole 11 are attached, 13 is a long hole, TC is a tape cassette, 14 is a supply reel, 15 is a take-up reel, 1
6 is a video tape. Further, A is the rotation direction of the head drum 2 (during normal reproduction), B is the loading direction, C is the unloading direction, and D is the insertion direction of the tape cassette TC.

In the conventional example, the dew condensation sensor 4 was attached to the chassis 1 (see FIG. 2). However, in this embodiment, the tape cassette TC is provided inside the VTR main body.
It is located on the side of the entrance of the insertion path, facing the insertion path. That is, the sensor mounting lever 22 is swingably supported on the support shaft 21 fixed to the chassis 1, and the dew condensation sensor 23 is mounted on the free end of the sensor mounting lever 22. The mounting height of the dew condensation sensor 23 is
It is within the upper and lower width of the cassette insertion path. One end of a spiral spring 24 whose central coil portion is fitted onto the support shaft 21 is fixed to the chassis 1 and the other end is locked to the sensor mounting lever 22, and the sensor mounting lever 22 is biased toward the cassette insertion path side. is doing. A stopper 25 for receiving the sensor mounting lever 22 at a specified position is provided on the chassis 1
Has been planted in. The dew condensation sensor 23 is located at a position slightly inserted into the cassette insertion path in a state in which the sensor mounting lever 22 is received by the stopper 25 while being biased by the spiral spring 24. The dew condensation sensor 23 is connected to the control circuit 5 via the lead wire 17. Like the conventional example, the dew condensation sensor 23 is configured so that the resistance value increases when dew drops adhere to the surface thereof. In the control circuit 5 as well, as in the conventional example, the dew condensation sensor 23 detects the adhesion of dew drops and the resistance value thereof is higher than the reference value, and when the dew drop detection signal is input from the dew condensation sensor 23, the tape loading mechanism. 3 is configured to prohibit the loading operation of the video tape 16 onto the head drum 2 according to the third example.

Next, the operation will be described. Tape cassette T
By pressing a recording button or a reproduction button on the operation panel with C loaded, a command for recording operation or reproduction operation is given to the control circuit 5. Then, the control circuit 5 reads the state of the dew condensation sensor 23. However, when the dew drop does not adhere to the dew condensation sensor 23 and its resistance value is a low reference value, the control circuit 5 A loading command is given to the tape loading mechanism 3. As a result, the pole bases 8 and 12 move in the B direction in the long holes 9 and 13, and the video tape 16 is wound around the peripheral surface of the head drum 2, and recording or reproduction is performed.

If the atmosphere in the room in which the VTR is installed is humid and the head drum 2 is dewed, dew condensation occurs on the dew condensation sensor 23 regardless of whether the tape cassette TC is attached or not. There is. Especially VT
When R is carried from a cold room to a humid room,
Condensation occurs on the head drum 2 and the condensation sensor 4 almost simultaneously.
Condenses even. In this way, when the dew condensation sensor 4 detects a dew drop and the resistance value thereof is higher than the reference value, the control circuit 5 is instructed to perform a recording operation or a reproduction operation, and the control circuit 5 causes the dew condensation sensor 23 to operate. When the state is read, the control circuit 5 inputs the dew drop detection signal due to the resistance value of the dew condensation sensor 23 increasing from the reference value, and prohibits the operation of the tape loading mechanism 3. As a result, it is possible to avoid the tape damage caused by the video tape 16 sticking to the head drum 2 via the dew drop.

The dew condensation state of the VTR main body (head drum 2) may differ from the dew condensation state of the tape cassette TC. In particular, when the tape cassette TC is carried from a low temperature room to a humid room, the water vapor in the atmosphere is cooled by the housing of the tape cassette TC having a low temperature to be condensed to the housing of the tape cassette TC. Condensation occurs on the surface of the video tape 16.
At this time, even if dew condensation does not occur on the VTR main body (head drum 2), if the video tape 16 with dew condensation is loaded on the head drum 2, the video is transmitted via dew drops. Tape 16 is head drum 2
Sticking to the tape may damage the tape.

However, in the case of this embodiment, the dew condensation state of the tape cassette TC can be detected when the tape cassette TC is inserted into the VTR main body. That is, V
When the tape cassette TC is inserted from the cassette insertion opening of the TR main body, the side surface of the tape cassette TC is dew condensation sensor 23.
The dew drop that is in sliding contact with and adheres to the housing of the tape cassette TC adheres to the dew condensation sensor 23. When the dew condensation sensor 23 is pushed by the side surface of the tape cassette TC, the sensor mounting lever 22 swings around the support shaft 21 against the spiral spring 24, but the urging force of the spiral spring 24 increases and the sensor mounting Dew condensation sensor 23 via lever 22
Is pressed against the side surface of the tape cassette TC with a predetermined pressure. Therefore, the dew drop adhering to the side surface of the tape cassette TC is satisfactorily squeezed to the dew condensation sensor 23. As a result, the resistance value of the dew condensation sensor 23 becomes higher than the reference value, and the dew condensation sensor 23 is in a state of outputting a dew drop detection signal. The inserted tape cassette TC once moves to the back side, then moves to the lower side and is set to the reference height. At this time, the pole bases 8 and 12 enter the inside of the video tape 16.

When a recording operation or a reproducing operation command is given to the control circuit 5, the control circuit 5 reads the state of the dew condensation sensor 23, but the dew condensation sensor 23 outputs a dew drop detection signal. The control circuit 5 prohibits the operation of the tape loading mechanism 3 in spite of the recording / reproducing command. That is, even if there are no dewdrops on the VTR main body and then on the head drum 2, if the dewdrops are on the tape cassette TC, the loading operation of the video tape 16 is prohibited. As a result, it is possible to avoid tape damage caused by the video tape 16 sticking to the peripheral surface of the head drum 2 via dew drops.

In the above embodiment, the dew condensation sensor 23 is provided at a position facing the cassette insertion path, but the present invention is not limited to this, and the dew condensation sensor 23 is arranged at the cassette loading portion. It may be a part facing. Further, the contact portion of the dew condensation sensor 23 with respect to the tape cassette TC may be any portion on the surface other than the side surface of the tape cassette TC, and may be configured to contact the video tape 16 itself. In addition, the dew condensation sensor 23
The timing at which the tape comes into contact with the tape cassette TC is
Head drum 2 of video tape 16 from the time of cassette insertion
To the end of the loading for any time. However, it is preferable to detect as early as possible in consideration of the reliability of dew condensation detection, and in that sense, it is preferable that the cassette is inserted.

[0022]

As described above, according to the present invention, not only the dew condensation sensor can detect the dew condensation state of the head drum, but also the dew condensation state of the tape cassette itself can be directly detected by the contact with the tape cassette. be able to. Therefore, when there is no dew drop on the head drum itself, it differs from a dry head drum such as a tape cassette in which dew condensation is abruptly caused by being carried from a low temperature room to a humid room. Even if you insert a tape cassette that has dew droplets on it, the dew drop detection signal is sent to the control circuit by directly detecting the dew condensation state of the tape cassette by bringing the dew condensation sensor into contact with the tape cassette. Since the loading operation is prohibited, the tape damage can be avoided.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a cassette loading portion of a VTR having a dew condensation detecting device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a cassette loading portion of a conventional VTR having a dew condensation detecting device.

[Explanation of symbols]

 1 Chassis 2 Head Drum 3 Tape Loading Mechanism 5 Control Circuit 8 Pole Base 12 Pole Base 14 Supply Reel 15 Take-up Reel 16 Video Tape 17 Lead Wire 21 Spindle 22 Sensor Mounting Lever 23 Condensation Sensor 24 Twisting Spring 25 Stopper TC Tape Cassette

Claims (1)

[Claims] 1. A dew condensation detecting device having a control circuit for prohibiting a loading operation of a video tape onto a head drum when a dew condensation sensor detects dew drop adhesion,
The dew sensor is arranged inside the VTR main body so as to be in contact with the tape cassette at a position facing the insertion path or the loading position of the tape cassette.
Condensation detection device in TR.