JPH03116575A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To lengthen the still endurance time under a still mode by forming a diameter of a rotary drum slightly larger than a diameter of a fixed drum and forming also a length of a tapered part to be >=1mm and positional relationship between the lowermost end part of the tapered part and a tape facing surface of the fixed drum to be approximately aligned. CONSTITUTION:The rotary drum 1 is slightly laser than the fixed drum 4 in diameter, and the tapered part 8 is of its length of >=1mm and formed to make the positional relationship between the lowermost end part of tapered part 8 and the tape facing surface of the fixed drum 4 approximately aligned. In this case, since the tape length and tape depth of the tapered part of the rotary drum are appropriate, the occurrence of waving is small as to be <=0.002mm. Then, since deformation shape in floating a tape and inclination of the tapered part are parallel to each other, an air layer between the tape and the tapered part is unified in thickness. By this method, air pressure on the surface of the tapered part is raised, so that the tape is easily floated up from the tapered part, and contact sliding between the rotary drum and the tape is eliminated, thus promoting the still endurance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for recording by winding a tape around the outer circumferential surface of a rotating drum and bringing the tape into contact with a head provided on the outer circumference of the rotating drum. The present invention relates to a recording and reproducing device that performs reproduction.

Conventional helical scanning type VTRs have a so-called still mode in which the tape stops, in addition to normal recording and playback modes in which the tape runs at a predetermined tape speed.

In this still mode, the tape remains wrapped around the outer circumferential surface of the rotating drum, so the head installed on the outer circumferential surface of the rotating drum can continuously and repeatedly scan the same trajectory on the tape. , and the head continuously reproduces the manipulated signals, resulting in a static playback screen.

Next, the behavior of the rotating drum and tape in still mode will be explained. FIG. 2 shows a drum unit in a helical scanning type VTR. In FIG. 2, 1 is a rotating drum, 2 is a head attached to the rotating drum, 31L and 3b are windows provided for protruding the head from the rotating drum, 4 is a fixed drum,
Reference numeral 5 denotes a lead portion provided on the fixed drum to accurately guide the tape. FIG. 3 shows a state in which the tape 6 is helically wound around the drum unit of FIG. 2.

The lower end of the tape 6 is guided along a lead 6 of the fixed drum 4.

FIG. 4 is a sectional view taken from the entrance direction in FIG. 3. 1
is a rotating drum, and the window portion 3a and the window portion 3 in FIG.
A cross section is shown between b. The tape 6 is guided to the lead portion 5 of the fixed drum 4 and is wound around the drum unit.

In FIG. 4, the diameter of the rotating drum 1 is equal to the diameter of the fixed drum 4.
0 to 0.02ffff than the diameter of the tape facing surface 7 of
It's getting bigger. That is, the outer periphery of the rotating drum 1 is shaped to protrude outward from the tape facing surface 7 of the fixed drum 4. This is because by protruding the rotary drum 1, a downward force is applied to the tape 6 in the figure, and the tape 6 is made to run stably without separating from the lead portion 6 of the fixed drum 4. If the outer periphery of the rotating drum 1 does not protrude beyond the tape facing surface 7 of the fixed drum 4, the tape 6 will easily separate from the lead portion 6, resulting in an unstable running condition.

In FIG. 4, the tape 6 is attached to the rotating drum 1 due to the pressure of the air flow generated around the outer circumference of the rotating drum 1 rotating at high speed.
It is floating from the outer periphery of. However, since there is a gap between the rotating drum 1 and the fixed drum 4, the pressure of the air flow is low, and the tape 6 cannot float sufficiently above the rotating drum 1 near the lower end of the rotating drum 1. Furthermore, the outer circumference of the rotating drum 1 is smaller than the tape facing surface of the fixed drum 4.
Because of the outward protrusion, the tape 6 comes into contact with the rotating drum 1 near its lower end. In the still mode, the tape is stopped, so the lower end of the rotating drum 1, which rotates at high speed, continuously and repeatedly scans the same trajectory of the tape 6 for a long time while sliding in contact with the surface of the tape 6. As a result, the recording layer on the surface of tape 6 peels off, causing tape damage.
It becomes impossible to play with the head. Methyl durability refers to how long a tape can be used in still mode without damaging the tape.

FIG. 6 shows an example of the configuration of a drum unit having a conventional rotating drum proposed for the purpose of improving the durability of methyl. In this conventional example, a tapered portion 8 is provided at the lower end of the rotating drum 1.

Due to this tapered portion 8, the lowermost end B of the rotary drum 1 is located radially inward compared to the case without the tapered portion 8, so that it becomes difficult to contact and slide against the surface of the tape 6. Therefore, when the tape 6 is stopped in the still mode, the time that the tape can be used without being damaged becomes longer. In other words, still durability can be improved.

The factors that determine the action of the tapered portion 8 include the taper length and the taper depth. For example, in FIG. 6, if the taper length Y is large or the tape (depth case,
The tape 6 tends to separate from the lead portion 6 of the fixed drum 4, resulting in an unstable running condition. So-called waving is more likely to occur. This is because, as mentioned above, by making the outer periphery of the rotating drum 1 protrude outward from the tape facing surface 7 of the fixed drum 4, a force directed downward in the figure is applied to the tape and the running of the tape 6 is stabilized. If the tapered portion 8 is too large, the tape will be recessed inward in the radial direction, reducing this effect, weakening the downward force, and making running unstable. In other words, waving is more likely to occur, and becomes more than o, oo21n.

Also, if the taper length Y or taper depth X is small,
Still durability cannot be sufficiently improved. FIG. 6 is a diagram showing a case where the taper length Y is small. In FIG. 6, the taper length Y is too small, so in the still mode, the tape e is placed at the boundary C between the outer periphery of the rotating drum 1 and the tapered portion 8.
Tape damage tends to occur due to contact and sliding at some parts, and the durability of the tape is not sufficiently improved, and the short time is, for example, about 1 hour. FIG. 7 is a diagram showing a case where the taper depth X is small and the positional relationship between the lowermost end B of the tapered portion 8 and the upper end of the tape facing surface of the fixed drum is 0.00311M or more. In FIG. 7, the tape depth If there is no improvement and the time is short, it will be about 1 hour, for example.

Problems to be Solved by the Invention In the conventional configuration, the taper length or taper depth of the tapered part of the rotating drum is not set appropriately, and if the taper length or taper depth is large, the tape is fixed at the lead part of the drum. The force pressing against the surface becomes weaker and waving is more likely to occur, and the weight is 0.002 g or more. In addition, if the taper length or taper depth is small, the tape will come into contact with a part of the rotating drum, causing damage to the tape, and the methyl durability will not be sufficiently improved. It had

The present invention is intended to solve the above-mentioned conventional problems, and aims to provide a recording/reproducing device that causes little waving and has sufficient still durability.

Means for Solving the Problem In order to achieve this object, the recording/reproducing device of the present invention has a rotating drum having a diameter slightly larger than that of a fixed drum, a tapered portion having a tapered portion of 1ffj1 or more, The positional relationship between the lowermost end of the fixed drum and the tape facing surface of the fixed drum is substantially aligned.

Effect: With this configuration, the taper length and taper depth of the tapered portion of the rotating drum are appropriate, so that the occurrence of waving is small, and is 0.002 wty or less. Further, since the floating deformation shape of the tape and the inclination of the tapered portion are substantially parallel, the thickness of the air layer between the tape and the tapered portion becomes uniform. Therefore, the air pressure on the surface of the tapered portion increases, and the tape easily floats up from the tapered portion, thereby eliminating sliding contact between the rotating drum and the tape.

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

FIG. 1 shows a drum unit of a recording/reproducing apparatus in an embodiment of the present invention. In FIG. 1, the taper length Y of the tapered portion 8 of the rotating drum 1 is 1 to 1.6 WII. In addition, the taper depth and its depth X is 0” due to manufacturing reasons.
There are variations between Jo and 02MM.

The operation of the recording/reproducing apparatus having the drum unit configured as described above will be described below.

First, the taper length X and the tape (depth
The outer periphery of the tape 6 is made to protrude outward from the tape facing surface 7 of the fixed drum 4 to apply a downward force to the tape 6 in the figure, so that the tape 6 can run stably. As a result, the waving becomes 0.002 ff or less.

Next, the portion of the tape 6 above the point about 1 to 2 mm from the lowest end B of the rotating drum 1 is designated as E, and the portion of the tape below the top end of the fixed drum 4 is designated as F. The floating deformation shape of the tape 6 from the rotating drum 1 and the fixed drum 4 is E
Sections and F sections are mostly related to the shape of the tapered section 8 of the rotating drum 1 or the amount by which the outer periphery of the rotating drum 1 protrudes outward from the tape facing surface 7 of the fixed drum 4 (this is referred to as a vertical step difference). It is constant. and,
The most natural floating deformation shape in the G section between the E section and the F section is a shape that smoothly connects the constant floating deformation shapes of the E section and F section. Taper length Y from 1 to
1.5ffj1, and the taper depth is set so that the positional relationship between the lowermost end B of the tapered portion 8 and the upper end of the tape facing surface 7 of the fixed drum 4 is within ±0.005 with respect to the radial direction of the rotating drum 1. When X is set, the tapered part 8 and the floating deformed shape of the tape 6 in the G part become almost parallel. Therefore, the thickness of the air layer between the tape 6 and the tapered portion 8 becomes uniform.

Then, the air pressure on the surface of the tapered portion 8 increases, and the tapered portion 8
The tape 6 becomes easier to float. Therefore, there is no sliding contact between the rotating drum 1 and the tape 6, and the durability time of still V in the still mode can be increased, for example, a value of 10 hours or more can be obtained.

Effects of the Invention As described above, the present invention provides a rotary drum in which the tapered portion of the rotating drum has a taper length of 1 mm or more, and the positional relationship between the lowest end of the tapered portion and the upper end of the tape facing surface of the fixed drum is almost aligned. The waving is o, 002M.
Since the tape becomes easier to float from the tapered portion, it is possible to obtain the effect that the methyl durability time in the still mode can be extended.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a drum unit of a recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a drum unit of a helical scanning type VTR.
Fig. 3 is a perspective view showing the drum unit in Fig. 2 with HC tape wrapped around it, Fig. 4 is a sectional view taken from the direction of Fig. 3, and Figs. 6 and 7 are main parts of a conventional drum unit. FIG. 1...Rotating drum, 4...Fixed drum, 6...Tape, 7...Tape facing surface of fixed drum, 8...Tapered portion .

Claims (1)

[Claims] A pair of rotating drums and fixed drums provided coaxially,
The rotating drum includes a tapered part provided on the outer periphery of the rotating drum, and a lead part provided on the lower periphery of the fixed drum for regulating tape running, and the rotating drum has a diameter slightly smaller than the fixed drum. The recording/reproducing device is characterized in that the tapered portion has a length of 1 mm or more and is formed so that the lowermost end of the tapered portion and the tape facing surface of the fixed drum are substantially aligned.