JPH02287940A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To accurately detect the occurrence of a dew condensation state in a cylinder and a tape guiding member, etc., by providing plural dew condensation detecting elements which detect the humidity state in an area including the traveling system of a magnetic tape. CONSTITUTION:Two dew condensation detecting elements 2a and 2b are provided in a specified range including the traveling system of the magnetic tape 8 in a VTR part 7. When a temperature suddenly changes inside the VTR part 7 by opening a lid 1 and dew condensation occurs, the element 2a directly detects the occurrence of the dew condensation and then the element 2b detects the occurrence of the dew condensation. When it is dried inside the VTR part 7, thereafter, the element 2a detects the resolution of the dew condensation first and the element 2b detects the resolution of the dew condensation as the dew condensation of the cylinder 4 is resolved. Thus, the point of time when the dew condensation starts to occur inside the VTR part 7 is detected by the detection output from the element 2a and the point of time when the dew condensation is resolved is detected by the detection output from the element 2b.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording and reproducing device such as a VTR that uses a magnetic tape as a recording medium, and particularly relates to a magnetic recording and reproducing device such as a VTR that uses a magnetic tape as a recording medium, and in particular a member such as a cylinder that the magnetic tape runs in contact with. The present invention relates to a dew condensation detection device.

[Conventional technology]

In a VTR, a magnetic tape pulled out from a tape cassette travels while being guided by various tape guide members and comes into contact with a cylinder equipped with a magnetic head.From there, the magnetic tape is guided by various tape guide members and comes into contact with various magnetic heads. Drive close to each other.

The tape is taken up on the take-up reel of the tape cassette. When running a magnetic tape in this manner, if dew condensation forms on the cylinder or tape guide member, the magnetic tape may stick to it and, in the worst case, become tangled.

In order to prevent this, in Japanese Patent Application Laid-Open No. 58-128038, since dew condensation occurs when the temperature suddenly drops by more than a predetermined value, the tape cassette is removed when the temperature difference inside and outside the VTR is more than a predetermined value. If the lid opens when the VTR is inserted, there is a high possibility that the surface of the cylinder will cool down suddenly and condensation will form. Therefore, when the temperature difference between the inside and outside of the VTR is detected and this temperature exceeds the predetermined value mentioned above, current is applied to the heater. A technique has been disclosed that makes it possible to obscure the difference between the series and the data.

(Problem to be Solved by the Invention) However, according to the above-mentioned prior art, the possibility of dew condensation occurring is determined by detecting the temperature difference inside and outside the VTR, and it is difficult to determine whether condensation actually occurs inside the VTR. Therefore, as mentioned above, when using a heater to prevent condensation, even if no condensation actually occurs.

When the temperature difference between the inside and outside of the VTR exceeds the predetermined value, current flows through the heater to heat it. Of course, even if you open the lid when there is this temperature difference, no condensation will occur because the cylinder etc. are heated, but when the temperature difference before opening the lid exceeds the above predetermined value, the heater Even if no tape cassette is inserted or removed from the start of use to the end of VTR use, current is often applied to the heater and power is wasted6, especially when using a VTR with a built-in camera. As such, in a portable VTR using a battery, power consumption by the heater is a major problem, and it is not suitable to apply the above-mentioned conventional technology.

In addition, in the above-mentioned conventional technology, it is very difficult to determine the temperature difference that can accurately detect the occurrence of dew condensation on the cylinder, and if this temperature difference is set large,
Even if N dew actually occurs, it may not be heated by the heater, and if this temperature difference is set to a small value, heating may be performed by the heater even if no dew condensation occurs.

Furthermore, when dew condensation occurs, it is possible to set the VTR in stop mode to prevent the magnetic tape from connecting to the cylinder or tape guide member. Conventional techniques cannot be applied.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording and reproducing apparatus that solves these problems and can accurately detect the occurrence of dew condensation on cylinders, tape guide members, and the like.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a plurality of dew condensation detection elements within a predetermined range including the tape running system.

[Effect]

The dew condensation detection element detects the dew condensation state by detecting the humidity state. A plurality of dew condensation detection elements are installed at different positions within a predetermined range including the tape running system, and detect the dew condensation state at each position. Thereby, it is possible to accurately detect the time from the time when dew condensation starts to the time when it ends within this predetermined range, and it is possible, for example, to stop the magnetic recording/reproducing apparatus during this period.

Within the above specified range, when using the lid, there are places where dew condensation occurs quickly, dries quickly and dew condensation disappears quickly, and places where condensation is the opposite. By determining the installation position, it is possible to accurately detect the period from when dew condensation starts to when it ends in the predetermined range.

〔Example〕

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

1 to 5 show an embodiment of a magnetic recording/reproducing device according to the present invention, in which FIG. 1 is a cross-sectional view, FIG. 2 is a longitudinal sectional view, FIG. 3 is an external view, and FIG. 4 and 5 are block diagrams showing specific examples of the dew condensation detection circuit, respectively.

Here, a camera-integrated VTR will be described as a portable magnetic recording/reproducing device. This camera-type VTR is
As shown in FIG. 3, a lid 1 is provided which can be opened and closed by rotating in the direction indicated by the VTRTlO2 mark.The lid 1 is opened and closed as shown in the figure, and the tape cassette 5 is pushed in the direction of the arrow.
Thereafter, by pushing the lid 1 in the direction of the arrow to close it, the tape cassette 5 is installed in the VTR unit 7. In addition, by operating the VTRTlO2 eject button, the lid 1
rotates in the direction of the arrow opposite to that described above, and then the tape cassette 5 pops out a predetermined amount in the direction of the upward arrow, and the tape cassette 5 is taken out.

FIG. 1 is a sectional view taken along a plane including the xx' axis in FIG. 3 and perpendicular to the YY' axis, and is a sectional view taken along the second drawing. However, in the same figure, 1 is the lid, 2a and 2b are the condensation detection elements, 3 is the main body case, 3a is the gap, 4 is the cylinder, 5 is the cassette tape, 6 is the chassis, and 7 is the VTR.
Part 8 is a magnetic tape.

In the figure, two dew condensation detection elements 2a and 2b are provided within a predetermined range including the running system of the magnetic tape 8 inside the VTR unit 7. The dew condensation detection element 2a is arranged directly under the gap 3a between the lid 1 and the main body case 3.
b is the cylinder 4 at the back of the main body case 3, which is related to the lid 1.
located nearby. These dew condensation detection elements 2a, 2b
has a characteristic that its resistance value changes when dew condensation occurs on its surface, and it is detected that dew condensation has occurred based on this change in resistance value.

By the way, at the position where the dew condensation detection element 2a is arranged, when the lid 1 is opened, it is directly exposed to the flow of outside air, so that the V
Inside the TR section 7, the sudden change in outside temperature is the quickest, and therefore dew condensation occurs the quickest6.Furthermore, due to the flow of outside air, drying is quick and dew condensation is eliminated the quickest. On the other hand,
At the position where the dew condensation detection element 2b is arranged, the dew condensation detection element 2
Compared to the position where a is placed, the sudden change in temperature due to the flow of outside air is delayed, so the formation of dew is delayed, and once condensation occurs, it takes a long time to dry, and the heat capacity is relatively large. The dew condensation disappears almost simultaneously with the dew condensation in the cylinder 4 being eliminated.

Therefore, when the lid 1 opens and the temperature suddenly changes inside the VTR unit 7 and condensation occurs, the condensation detection element 2
The dew condensation detection element 2b immediately detects the occurrence of dew condensation. After this, when the inside of the VTR unit 7 becomes dry, the condensation detection element 2a first detects that the condensation has disappeared, and the condensation in the cylinder 4 is eliminated.
The dew condensation detection element 2b detects the elimination of dew condensation. From this, the detection output of the dew condensation detection element 2a can detect the start point of dew condensation inside the VTR section 7, and the detection output of the dew condensation detection element 2b
The point at which the condensation is eliminated can be detected by the detection output.

Next, a specific example of the dew condensation detection circuit will be explained with reference to FIG.

In the figure, it is assumed that the resistance values of the dew condensation detection elements 2a and 2b increase due to dew condensation. Condensation detection elements 2a, 2b
are connected in series, and the divided voltage electrons of the power supply voltage from the power supply terminal 9 by the resistor 1o and the dew condensation detection elements 2a and 2b are supplied to the voltage comparator 13 as the input voltage E. Also, resistance 1
A divided voltage of the power supply voltage according to 1.12 is supplied to the voltage comparator 13 as the reference voltage E2. The voltage comparator 13 compares the input voltage E and the reference voltage E2, and outputs a voltage of "■" (high level) when E1≧E8 and "L" (low level) when E<E2. .

Here, when dew condensation occurs on the dew condensation detection elements 2a and 2b, their resistance values increase and the input voltage E□ rises. The resistance values of the resistors 10 to 12 are set so that when the value increases, E<E2>.

Therefore, when neither of the dew condensation detection elements 2a and 2b detects dew condensation, the output voltage of the voltage comparator 13 is 11
L II, the output voltage of the voltage comparator 13 becomes "H" during the period from when the dew condensation detection element 2a detects the occurrence of dew condensation to when the dew condensation detection element 2b detects the elimination of dew condensation.
The microprocessor 14 constantly monitors the output level of the voltage comparator 14, and when it becomes "H", it determines that dew condensation has occurred within a predetermined range including the tape running system in the VTR section 7. The section 7 is placed in the stop mode.

Next, another specific example of the dew condensation detection circuit will be explained with reference to FIG.

In the figure, it is assumed that the resistance values of the dew condensation detection elements 2a and 2b decrease due to dew condensation. Condensation detection elements 2a, 2b
are connected in parallel, and a divided voltage of the power supply voltage from the power supply terminal 9 by the resistor 15 and the parallel circuit of the dew condensation detection elements 2a and 2b is supplied to the voltage comparator 13c as the input voltage E□.

Further, the divided voltage of the power supply voltage by the resistor 16.degree. 17 is supplied to the voltage comparator 13 as the reference voltage E2. The voltage comparator 13 operates in the same manner as in the case of FIG. 4, but when condensation is detected in at least one of the dew condensation detection elements 2a, 2b and the resistance value decreases, the parallel circuit of the dew condensation detection elements 2a, 2b is activated. Since the resistance value of E8 also decreases, the input voltage E8 decreases. When neither of the dew condensation detection elements 2a and 2b detects dew condensation, the output level of the voltage comparator 13 is L.
The resistors 15 to 1 are set so that the output level of the voltage comparator 13 becomes "L" when the resistance value of at least one of the dew condensation detection elements 2a and 2b decreases due to condensation.
7. Set the resistance value etc.

In this way, the output level of the voltage comparator 13 is determined by the dew condensation detecting element 2a after the dew condensation detecting element 2a detects the occurrence of condensation.
The microprocessor 14 constantly monitors this output level, which remains "L" until b detects that the condensation has disappeared.
When this reaches 41 L 17, it is determined that dew condensation has occurred within a predetermined range including the tape running system within the VTR section 7, and the VTR section 7 is placed in a stop mode, for example.

In addition, in FIG. 4, the dew condensation detection elements 2a and 2b may be connected in parallel, or as shown in FIG. 5, the dew condensation detection elements 2a and 2b may be connected in series. , in FIG. 4, the condensation detection elements 2a, 2b connected in series or in parallel may be replaced with the resistor 10, and in FIG. 5, the condensation detection elements 2a, connected in parallel or in series may be replaced.
, 2b may be replaced with the resistor 15.

As described above, in this embodiment, by installing the dew condensation detection element 2a in a place where dew condensation is likely to occur quickly, and by installing the dew condensation detection element 2b in a place near the cylinder 4 where it is difficult to dry, dew condensation in the tape running system can be prevented. The occurrence of dew condensation can be detected immediately, and the slow release of dew condensation in the cylinder 4, which has a relatively large heat capacity, can be detected with a relatively small time error.

Therefore, the detection accuracy during the period when dew condensation actually occurs becomes high.

In the above embodiment, two dew condensation detection elements are provided, but three or more may be provided.

In this case as well, these dew condensation detection elements are provided at different positions within a predetermined range including the tape running system in the VTR section 7, taking into account the occurrence of dew condensation, and in the dew condensation writing circuit, the fourth
As explained in FIG. 5 and FIG. 5, they are connected in series or in parallel. As a result, the microprocessor 14
It is possible to detect the period from the time when any of these dew condensation detection elements first detects the occurrence of dew condensation to the time when it last detects the elimination of dew condensation.

In addition, in a portable VTR, it is advantageous to set the stop mode during the period when dew condensation occurs in terms of power consumption, but some magnetic recording/reproducing devices do not turn on the heater during this period, as in the prior art. Heat with.

It may be dried.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to accurately detect the state of dew condensation within a predetermined box containing a tape running system, and it is possible to prevent loss of members of the tape running system and the magnetic tape.

[Brief explanation of the drawing]

11th! 1 to 5 show an embodiment of a magnetic recording/reproducing device according to the present invention, in which FIGS. 1 and 2 are sectional views, FIG. 3 is an external view, and FIGS. 4 and 5. 2A and 2B are block diagrams showing specific examples of dew condensation detection circuits, respectively. 1... Lid. 2a, 2b... dew condensation detection elements. 4...Cylinder. 5...Tape cassette. 8...Magnetic tape. Me/Kakko 20 No. 1, I

Claims (1)

[Claims] 1. In a magnetic recording and reproducing device that records and reproduces signals by running a magnetic tape, a plurality of dew condensation detection elements are provided in an area including the running system of the magnetic tape to detect humidity conditions. A magnetic recording/reproducing apparatus characterized by further comprising: arithmetic control means for arithmetic processing of the detection signals of each of the dew condensation detection elements to generate a control signal for operation control. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the installation positions of the respective dew condensation detection elements have different dew condensation and drying rates depending on the humidity state within the area.