JPH04176043A - Magnetic recording reproducer - Google Patents

Abstract

PURPOSE:To prevent the damage of an electrical part due to a short circuit when a water drops enters a device by detecting the change of a resistance value by a resistance-value detecting means when the resistance value of a conductive member is brought to a value except a specified value, operating a power control means and turning a power supply for the device OFF. CONSTITUTION:A circuit board is covered with a conductive member 6, and currents are made to flow through the conductive member 6 while a resistance- value detecting mans 8 and a power control means 9 are connected to the conductive member 6. When a water drops enter a device and adheres on the conductive member 6, the resistance value of the conductive member 6 changes from a specified value, and the power control means 9 is operated when the resistance-value detecting means 8 detects the change of the resistance value of the conductive member 6 from the specified value, and a power supply 7 for the device is turned OFF. Accordingly, the damage of an electrical part due to the adhesion of water drops to a circuit, causing short circuit can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to magnetic recording and reproducing devices frequently used outdoors, such as portable audio tape recorders, portable digital audio tape recorders (DAT), and video cameras. In particular, the present invention relates to a method for preventing failures caused by water droplets entering the inside of an apparatus.

[Prior Art] As described in Japanese Unexamined Patent Publication No. 1-290146, a conventional device is a magnetic recording/reproducing device using a rotating drum device equipped with a magnetic head, in which a dew condensation detection device is provided near the rotating drum device. When dew condensation is detected, a warning is issued by, for example, turning on a warning light in the viewfinder of the video camera, and the running of the tape is stopped.

[Problems to be Solved by the Invention] In the above conventional example, if the device gets wet with rain or is covered with water and water droplets enter the device, there is no means for directly detecting this. . Therefore, there was a problem in that it was impossible to prevent the water droplets from reaching the circuit section and causing a short circuit in one circuit.

An object of the present invention is to prevent water droplets from adhering to circuits in magnetic recording and reproducing devices that are frequently used outdoors, such as portable audio tape recorders, portable DATs, and video cameras, when water droplets enter the device. The object of the present invention is to provide a means for preventing damage to electric components such as ICs and LSIs due to short circuits.

[Means for Solving the Problems] In order to achieve the above object, the present invention covers a circuit board on which an electric component such as an IC1LSI is mounted with a conductive member such as a pattern of conductive wires, and allows current to flow through the pattern. The structure is such that a resistance value detection means and a power supply control means are connected to the conductive member.

Further, as another means for achieving the above object, a warning means is connected in place of the power supply control means.

Furthermore, as other means to achieve the above purpose,
Instead of covering the circuit board with conductive material.

The conductive member is arranged in the fitting portion of the device housing.

[Function] The resistance value detection means always detects the resistance of the conductive member. When water droplets that have entered the device adhere to the conductive member, the resistance value of the conductive member changes from a predetermined value. When the resistance value detection means detects that the resistance value of the conductive member has changed from a predetermined value, the resistance value detection means activates the power 1*J control means to cut off the power of the apparatus. Alternatively, a warning means is activated to warn of water droplets entering the device. This can prevent damage to electrical components such as ICs and LSIs due to short-circuits caused by water droplets directly adhering to the circuits.

[Example 7] Examples of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is an exploded perspective view showing a magnetic recording/reproducing apparatus according to an embodiment of the present invention. Note that this embodiment shows an example in which the present invention is applied to a video camera.

1 is a tape drive mechanism, 2 is a cassette attachment/detachment mechanism, 3 is a circuit board, and 4 is a housing. The housing 4 includes a housing 4a that is integrated with the tape drive mechanism 1, a housing 4b that is attached to the housing 4a with the circuit board 3 sandwiched therebetween, and a housing that is attached to the housing 4a from the same side as the cassette attachment/detachment mechanism 2. It is composed of a body 4C. Further, 5 is a lid attached to the cassette attachment/detachment mechanism 2. The tape drive mechanism 1, the cassette attachment/detachment mechanism 2, and the circuit board 3 are covered by the housings 4a to 4c and the lid 5, and are isolated from the outside. 6 is a conductive member. The circuit board 3 is completely covered by the conductive member 6.

FIG. 2 schematically shows the structure of the conductive member 6 and also shows the configuration of this embodiment. Reference numeral 10 denotes a conducting wire, and the conducting wire 10 is, for example, a band-shaped copper foil folded into a pattern as shown in the figure. Reference numeral 611 is a holding member that holds the conducting wire 10, and the material of the holding member 11 is , such as plastic or vinyl chloride. The conducting wire 10 is held in the shape shown in the figure by a holding member 11. Also,
Guide! 10 is exposed on the surface of the holding member 11. The circuit board 3 is completely covered with such a conductive member. At this time, care must be taken not to short circuit the circuit board 3 due to the copper wire 10.

Reference numeral 7 denotes a power source for passing current through the conductive wire 10 of the conductive member 6. The power source 7 is, for example, a small dry battery built into the video camera.

8 is a resistance value detection means for detecting a change in the resistance value of the conductive member 6. Reference numeral 9 denotes a power control means for turning off the power of the video camera. A voltage is always applied to the conductive wire 10 of the conductive member 6 by the power supply 7, and a predetermined current flows therethrough. If the video camera is exposed to water splashes such as raindrops,
There is a possibility that water droplets may enter through the gaps between the joints of the casing 4. When this water droplet adheres to the surface of the conductive member 6 covering the circuit board 3, the water droplet short-circuits the conducting wire 10.

Note that the pattern of the conducting wire 10 is made sufficiently fine so that attachment of small water droplets can be detected. When the conductive wire 10 is short-circuited by a water drop, the resistance value of the conductive wire 10 decreases. This change in resistance value is detected by resistance value detection means 8, and a signal is sent to power supply control means 9. At the same time as receiving the signal, the power supply control means 9 turns off the power supply circuit 12 of the video camera.

Note that the conductive member 6 is not limited to the structure shown in FIG. 2, and various structures can be applied, such as using a moisture-sensitive resistor, for example.

FIG. 3 is a circuit diagram showing an example of the resistance value detection means 8. 10 indicates a conductive wire of the conductive member 6, and 7 indicates the conductive wire of the conductive member 6.
13 is a resistor, 1 is a power source for passing current through the conductor 10
4 is a potential comparator. The potential comparator 14 compares the potential at the point shown in the figure with a preset reference potential V ref. When water droplets adhere to the conductive wire 1o, the resistance of the conductive wire 10 decreases, so the potential at point K increases.

The potential comparator 14 detects this change in potential, and the output signal of the potential comparator 14, which was low until then, switches to high. This signal is sent to the power supply control means 9.

According to this embodiment, even if the video camera is exposed to water while the power is on, such as during shooting, and the water droplets that have entered the video camera reach the vicinity of the circuit board,
Water droplets adhere to conductive materials earlier than to circuit boards, so
The video camera's power circuit can be disconnected before the circuit is shorted by water droplets. In addition, even if the video camera is exposed to water while the power is cut off, and the water droplets have reached the conductive material and even the circuit board inside, and you try to turn on the power without noticing, the conductive material The power won't turn on because there are water droplets on it. Therefore, short-circuiting of the circuit due to power input can be prevented.

Next, an embodiment of the magnetic recording/reproducing apparatus according to claim 2 will be described with reference to FIG.

FIG. 4 shows the configuration of this embodiment. The resistance value detection means 8 is connected to a warning means 15 such as a warning light or a warning buzzer attached to a video camera.

When the water droplets adhere to the surface of the conductive member 6, the water droplets short-circuit the conducting wire 10. When the conducting wire 1o is short-circuited by a water drop, the resistance value of the conducting wire 10 decreases. This change in resistance value is
It is detected by the resistance value detection means 8 and a signal is sent to the warning means 15. Upon receiving the signal, the warning means 15 warns the user of the video camera of the ingress of water droplets by lighting up a warning light installed in the housing or viewfinder of the video camera, or by sounding a warning buzzer. Warning.

According to this embodiment, when water droplets that have entered the video camera reach the vicinity of the circuit board and adhere to the conductive member 6 while the power is being input, the warning light or warning buzzer detects the water droplet entry. Therefore, the user of the video camera can take measures such as disconnecting the power supply circuit of the video camera and wiping off the water droplets inside the video camera before the circuit is short-circuited by water droplets. Also, if the video camera is exposed to water while the power is cut off, and the water droplets reach the conductive parts and even the circuit board inside, check whether the warning light is on or not.
The warning buzzer sounds to prevent short circuits caused by power input.

Next, an embodiment of the magnetic recording/reproducing apparatus according to claim 3 will be described with reference to FIGS. 5 to 7.

FIG. 5 is a perspective view of the video camera in a state where the lid 5 of the cassette attaching/detaching mechanism 2 is opened by the eject operation. From this state, when the cassette cartridge is inserted into the cassette holding portion 16 of the cassette attachment/detachment mechanism 2 and the lid 5 is pushed in the direction of the tape active mechanism 1, the lid 5 fits into the opening 17 of the housing 4c. Alternatively, the cassette cartridge is held in place by the cassette attachment/detachment mechanism 2,
The tape in the cassette cartridge is transported by tape drive mechanism 1.
driven by.

FIG. 6 shows the shape of the conductive member in this example. 10 is a conducting wire, and 11 is a holding member that holds the conducting wire 10 in the shape shown in the figure. The conductive member 6 has an annular rectangular shape and an opening 18 as shown in the figure. The size of the opening 18 is slightly larger than the planar area of the cassette cartridge and the cassette holding portion 16 of the cassette attachment/detachment mechanism 2, and slightly smaller than the opening 17 of the housing 4c.

FIG. 7 is a perspective view of a video camera equipped with the conductive member 6 of this embodiment. However, the cassette attachment/detachment mechanism is not shown, and the lid 5 of the cassette attachment/detachment mechanism is shown far away from the video camera body. As shown in the figure, the conductive member 6 is attached at a position where the opening 18 overlaps the opening 17 of the casing 4C. When occupying the lid 5 of the cassette attachment/detachment mechanism, the cassette cartridge and the cassette holder of the cassette attachment/detachment mechanism pass through the opening 18 of the conductive member 6 and are held in place, and at the same time, the lid 5
It fits into the opening 17 of. Since a gap is created in this fitting portion, if the video camera is exposed to water, water droplets are likely to enter. When water droplets enter from the fitting portion, the water droplets adhere to the surface of the conductive member 6 and short-circuit the conductive wire 10 of the conductive member 6. For this reason.

The resistance value of the conducting wire 10 decreases. If the conductive member of this embodiment is connected to the power supply 7 and the resistance value detecting means 8 shown in FIG. 2, this change in resistance value will be detected and the power supply circuit will be disconnected.

Further, the conductive member 6 is connected to the joint 1 between the casing 4a and the casing 4b.
9 and the joint 20 between the casing 4a and the casing 4c, the intrusion of water droplets into the video camera can be detected more reliably by arranging them in the gaps where water droplets are likely to enter.

Furthermore, if the resistance value detection means 8 is connected to a warning means 15 such as a warning light or a warning buzzer attached to the video camera as shown in FIG. 4 instead of the power supply control means 9, the user of the video camera can The intrusion of water droplets from the fitting portion is recognized by the warning provided by the warning means, and measures such as cutting off the power supply and wiping off the water droplets inside the video camera are taken.

According to this embodiment, the power supply circuit is cut off at the same time that water drops enter the inside of the video camera.

Since the intrusion of water droplets can be detected using a warning light or warning buzzer, it is possible to prevent not only short circuits caused by water droplets but also malfunctions caused by water droplets adhering to mechanical parts such as the tape drive mechanism.
Damage to parts due to rust etc. can also be prevented.

[Effects of the Invention] According to the present invention, when water droplets enter the inside of a magnetic recording/reproducing device, the power to the device is cut off before the water droplets adhere to the circuit and cause a short circuit, or the device is disconnected from the device. The user is informed of the ingress of water droplets by a warning means provided. For this reason, portable audio tape recorders and portable DAT
In magnetic recording and reproducing devices that are frequently used outdoors, such as video cameras, if the device is exposed to water and water droplets enter the device, the water droplets may adhere to the circuit and cause a short circuit, causing damage to ICs, LSIs, etc. Prevent damage to electrical parts. Further, it prevents malfunctions and damage to mechanical parts such as the tape drive mechanism due to water droplets adhering to mechanical parts such as the tape drive mechanism. . Furthermore, it also prevents the tape from being caught in the tape drive mechanism and damage to the tape due to water droplets adhering to the tape.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a magnetic recording and reproducing device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a conductive member according to this embodiment and a configuration diagram of this embodiment, and FIG. 3 is a resistance value detection FIG. 4 is a schematic diagram of a circuit of the means according to another embodiment of the present invention, FIG. 5 is a schematic diagram of a conductive member according to another embodiment of the present invention, and FIG. 6 is a magnetic recording/reproducing device. Perspective view of Figure 7 is 1
FIG. 1 is a perspective view of a magnetic recording/reproducing device equipped with a conductive member according to the present embodiment. 1...Tape drive mechanism, 2...Cassette attachment/detachment mechanism,
3... Circuit board, 4... Housing, 5... Lid, 6...
- Conductive member, 8... Resistance detection means, 9... Power supply control means, 15... Warning means. Part I Opening 6 --- 4' as a part 2 Figure 3 Figure r 4 --- Idenabirabi light compilation 4- Figure 17 1 -- Subsidiary part compilation 5 Figure f --- Tape ear 2 section 11 Monument 2-11 Kase/F-Arukuhosenkeikai 4α~4Q・-hentai s-'-@/6--Kasetsu H 10th year/7-Opening part 6 Figure 6-Conductive member 10- Conductor n-11 section waiting member Iθ-11 Sekiguchi group Fig. 7/--Tape section motion perturbation number 4α~4Q-fjf/Floor 6--Ta 1 section 171-- ]Book 4-c opening

Claims (1)

[Claims] 1. A tape drive mechanism (1) that runs a tape, which is a magnetic recording medium, a magnetic head that records and reproduces data signals by scanning the tape, and a cassette cartridge that stores the tape. a cassette attachment/detachment mechanism (2) that holds the cassette cartridge and places the cassette cartridge in a predetermined position; a circuit section (3) that controls the operation of the tape drive mechanism (1) and processes data signals; A housing (4) containing the drive mechanism (1) and the circuit section (3)
and a lid (5) attached to the cassette attachment/detachment mechanism (2) so as to fit into the housing (4), a conductive member ( 6), a power source (7) for passing a current through the conductive member (6), a resistance value detection means (8) for detecting a change in the resistance value of the conductive member (6), and the resistance value detection means. (8), and a power supply control means (9) for cutting off the power supply of the device, and when the resistance value of the conductive member (6) becomes other than a predetermined value, the resistance value detection means (8) A magnetic recording/reproducing device characterized in that a change in the resistance value is detected and the power supply control means (9) is activated to cut off the power source of the device. 2. Instead of the power supply control means (9), a warning means (15) such as a warning light or a warning buzzer is provided, and the conductive member (6)
When the resistance value of the resistance value is other than the predetermined value, the resistance value detection means (
2. The magnetic recording and reproducing apparatus according to claim 1, wherein the warning means (15) is actuated by detecting a change in the resistance value. 3. The conductive member (6) is connected to the housing (4) and the lid (5).
3. The magnetic recording/reproducing device according to claim 1, wherein the magnetic recording/reproducing device is disposed at a fitting portion between the magnetic recording device and the magnetic recording/reproducing device.