JPH04121853A - Tape supply speed detector - Google Patents

Abstract

PURPOSE:To accurately detect speed by providing plural guide rollers rotated by a tape, and forming roll-in air ejection groove with different ejecting directions on the circumferential planes of the guide rollers. CONSTITUTION:The guide rollers 6A, 6B are rotated centering a guide shaft 2 by friction with a tape 7. The air is rolled in the outer peripheral plane of a sleeve 6b by drift friction with the tape 7. A fishbone roll-in air ejection groove 11a is formed at the outer periphery of the sleeve 6b, and the air is introduced to the groove 11a, and it is ejected smoothly from both sides of the sleeve 6b by the inclination of the groove 11a, therefore, the frictional force of the tape 7 with the sleeve 6b can be sufficiently maintained. Thereby, since either the guide rollers 6A, 6B is always rotated surely synchronizing with the supply of the tape, the supply speed of the tape 7 can be accurately detected by photointerruptor 10.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention increases the running speed of a tape used as a recording medium in a magnetic recording/reproducing device, etc. by rotating a guide roller that rotates in synchronization with the running speed of the tape. This invention relates to a tape running speed detection device that can accurately detect tape running speed even when running.

(Prior Art) Conventionally, in a magnetic recording/reproducing device, etc., the running speed of a tape, which is a recording medium, is usually detected.

It is detected by the rotation speed of the capstan that runs the tape. However, in the case of high-speed tape feeding or high-speed searching, the capstan running drive cannot accommodate the desired tape running speed, so the tape running by the capstan is canceled and the tape is directly wound by the reel motor.

Therefore, it becomes necessary to detect the running speed of the tape by another means.

Therefore, the following method is generally used to detect this type of tape running speed.

The first detection method is to detect the tape feed speed by the number of rotations of the reel, and the second method is to use a rotating roller that guides the tape and rotates in synchronization with the tape running speed. There is a method in which a guide roller having a rotation detection plate that rotates integrally with the rotation roller is provided, and the running speed of the tape is detected from the rotation detection plate of the guide roller.

Here, the second method in particular will be explained based on FIG. 4.

FIG. 4(a) is a plan view of a main part of the tape running speed detecting device, and FIG. 4(b) is a side sectional view thereof. In FIGS. 4(a) and (b), 1 is the main body of the tape running speed detection device (hereinafter referred to as the detection device), 2 is the guide shaft implanted and fixed on the chassis S, 3 is the bearing, and 4 is the bearing 3. A spring 5 is a slit plate provided with a slit 5a, which is integrated with a guide roller 6, and is smoothly rotated around the guide shaft 2 by a bearing 3, so that the magnetic tape (hereinafter referred to as (referred to as tape) 7. 6a is a sleeve that covers the outer periphery of the guide roller 6, and this sleeve 6a is of the normal type P! A rubber material with a high J coefficient is used, and the tape 7 is configured to prevent slipping between the tape 7 and the running tape 7. 10 is a photointerrupter in which a light emitting element 8 and a light receiving element 9 are provided facing each other. The operation will be explained below based on FIG. First, the tape 7 is wound around the guide roller 6 and guided in its running. When the tape 7 runs, the guide roller 6 rotates due to the frictional force with the tape 7 in synchronization with the tape running speed. As a result, the slit plate 5 integrated with the guide roller 6 rotates in synchronization with the running speed of the tape 7.

At this time, this rotational speed is detected by a photointerrupter. In other words, the light emitted from the light emitting element 8 is transmitted through the slit 5.
a, the light is received by the light receiving element 9, and in the part where there is no slit 5a, the light is not received, so the light receiving element 9 outputs a rectangular wave according to the rotation speed, and the frequency of this rectangular wave is used to control the running of the tape 7. Speed is detected.

[To be solved by the invention] However, since the conventional example detects the tape running speed as described above, when the tape 70 runs at high speed, the tape 7 and the sleeve 6a of the guide roller 6 Since air is drawn into the contact surface between the tape 7 and the sleeve 6a and reduces the frictional force between the tape 7 and the sleeve 6a, thereby causing a slip between the tape 7 and the sleeve 6a, the rotation of the guide rod 6 causes the tape 7 to There was a problem in that the tape running speed could not be synchronized with the running speed of the tape, and as a result, the detection of the tape running speed became inaccurate.

This invention was made in order to solve the problems of the conventional methods as described above, and it provides a tape whose speed can always be accurately detected in synchronization with the tape running speed even when the tape is running at high speed. The purpose is to provide a traveling speed detection device.

[Means to solve the problem]

Therefore, the tape running speed detection device according to the present invention has the following features:
A plurality of guide rollers are provided which are rotated by the tape in synchronization with the running speed of the tape, and at least two of the plurality of guide rollers are provided with rollers arranged in different ejection directions on the circumferential surface of each guide roller. The above objective is achieved by forming the entrained air exhaust groove.

(Function) The tape running speed detecting device according to the present invention configured as described above has a configuration in which the discharge directions of the air caught in the surfaces of at least two of the plurality of guide rollers are different from each other. One of the guide rollers is provided with a groove for discharging the air that is drawn in when the tape runs at high speed. Therefore, regardless of the tape running direction, at least one guide roller always rotates in synchronization with the tape running without slipping caused by entrained air, and this guide The rollers always detect accurate tape running speed.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

(Structure) Fig. 1 is a plan view of the main parts of a tape running speed detection device showing one embodiment of the present invention, Fig. 2 is a side sectional view of the main parts, and Fig. 3 is a portion of the guide roller of the above embodiment. It is a front view.

Note that the same or equivalent parts as in the conventional example are represented by the same reference numerals.

In this embodiment, a case is shown in which the plurality of guide rollers are composed of two pieces.

In FIGS. 1 and 2, IA is the main body of the tape running speed detection device, 6A is the inner guide roller provided, and the sleeve 6 covered with the guide roller 6A is
A fishbone-shaped groove 11a, which is an air discharge groove A, as shown in FIG. 3(a), is formed on the outer peripheral surface of b. Also,
Reference numeral 6B designates the other of the two guide rollers, and a fishbone-shaped groove 11b is formed in the outer circumferential surface of a sleeve 6C covered with the guide roller 6B in a direction opposite to that of the sleeve 6b. The guide rollers 6A and 6B are made of a wear-resistant rubber material with a high coefficient of friction, and are rotated around the guide shaft 2 by friction with the tape 7 in synchronization with the running of the tape 7. is configured to do so.

(motion) The operation will be explained based on the above configuration.

First, when the tape 7 is driven by a reel (not shown) and travels in the direction of the arrow in FIG. 1, the guide rollers 6A, 6B rotate about the guide shaft 2 due to friction with the tape 7. As the tape 7 travels at higher speeds, air is drawn into the outer peripheral surface of the sleeve 6b due to the fluid friction of the tape 7. At this time, the air involved is as shown in Figure 3 (a).
As shown in , the guide roller 6A rotates in the clockwise direction, and therefore air is drawn into the circumferential surface of the sleeve 6b, but there is a fishbone-shaped drawn-in air discharge groove (hereinafter referred to as groove) on the outer circumference of the sleeve 6b. 11a is formed, and air is introduced into this groove and is smoothly discharged from both sides of the sleeve 6b due to the inclination of 1'la, so that the tape 7 and the sleeve 6
The frictional force with b is maintained sufficiently. As shown in FIG. 3(b), one of the guide rollers 6B has a fishbone-like inclination 11b on the circumferential surface of the sleeve 6C in a direction opposite to that of the groove 11a, so that the tape 7 runs in a clockwise direction. The wound air is rotated in a direction in which it is difficult to discharge, and the frictional force between the tape 7 and the sleeve 6C becomes lower than the frictional force between the sleeve 6b and the tape 7.

When the running direction of the tape 7 is reversed, the effect is completely opposite to that described above, and the frictional force between the sleeve 6C and the tape 7 during high-speed running is sufficiently maintained, regardless of the running direction of the tape 70. Since either one of the two guide rollers 6A, 6B always rotates reliably in synchronization with the running of the tape 7, the running speed of the tape 7 can be accurately detected by the photointerrupter 1o.

Next, other embodiments will be described.

In this embodiment, the number of slits provided in the slit plate 5 of the previous embodiment is different from each other, and the frequency characteristics of the photointerrupter 10 are set respectively for high-speed rotation detection and low-speed rotation detection when detecting the running speed of the tape 7. The structure is such that the tasks are divided.

This makes it possible to accurately detect tape running speeds over a wide speed range from low speeds to high speeds. However, in this embodiment, accurate tape running speed can be detected only in one direction.

In addition, in the above embodiment, the grooves 11 on the sleeves 6b, 6c
Although the shapes of a and llb are fishbone-shaped in opposite directions, the present invention is not limited to this. The two guide rollers 6A and 6B may be provided in opposite directions and set in any shape.

Furthermore, the number of guide rollers is not limited to two, and a plurality of guide rollers may be provided. In this case, the directions of the exhaust grooves for the air caught in the circumferential surfaces of at least two guide rollers are opposite to each other. The entrained air exhaust groove may be formed in this way.

(Effects of the Invention) As explained above, according to the present invention, a plurality of guide rollers for detecting tape running speed are provided, and at least two guide rollers of the plurality of guide rollers have mutually arranged circumferential surfaces. Since a trap air exhaust groove in the opposite direction is formed in the tape so that it rotates as the tape runs, there is always at least a minimum resistance to the tape running even when the tape is running at high speed, regardless of the running direction of the tape. The single guide roller rotates reliably in synchronization without slipping due to entrained air, thereby making it possible to accurately detect the tape running speed in the entire range from low to high speed.

[Brief explanation of drawings]

FIG. 1 is a plan view of the main parts of a tape running speed detection device showing an embodiment of the present invention, FIG. 2 is a side sectional view of the main parts, and FIG. 3 is a partial front view of the kite roller of the above embodiment. FIG. 4(a) is a plan view of a main part of a conventional tape running speed detecting device, and FIG. 4(b) is a side sectional view of the main part. 1, I A-----Tape running speed detection device body 6 6A, 6B--Guide roller 11 a
, 1 l b---Fish-shaped groove A...
・Entrained air exhaust groove In each figure, the same or equivalent parts are indicated by the same symbols.

Claims (1)

[Claims] A plurality of guide rollers are provided which are rotated by the tape in synchronization with the running speed of the tape, and at least two of the plurality of guide rollers are provided with rollers arranged in different ejection directions on the circumferential surface of each guide roller. A tape running speed detection device characterized by forming an entrained air exhaust groove.