JP2505011Y2 - Tape transport device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] A tape transporting device for transporting a tape in the form of a strip, which is sandwiched between a pinch roller made of a columnar elastic rotating body and a capstan which is a drive shaft, and pressed and held. In particular, the present invention relates to a tape transport device having a high running stability suitable for use in a high-density recording / reproducing device and the like.

[Outline of device]

The present invention relates to a tape transporting device for transporting a band-shaped tape while sandwiching it between a pinch roller and a capstan, pressing and holding the tape, wherein the pinch roller is provided with an automatic centering mechanism, and a diameter of a central portion of an outer peripheral surface of the pinch roller is provided. Is a tape conveying device having a pinch roller, in which the diameter of the tape is made smaller than the diameter of both ends thereof.

[Conventional technology]

It is well known that, in an apparatus for transporting a belt-shaped tape, the tape is transported by capping and supporting the tape with a pinch roller made of a cylindrical elastic body against a capstan serving as a drive shaft. , Is used in many devices such as tape recorders. It is also known that when there is unevenness in the tape pressing force on the capstan, the tape is pulled in the direction in which the tape pressing force is strong and the tape position moves up and down, and the tape meanders. Problems such as the tape coming off may occur. As measures against such a problem, for example, the techniques disclosed in Japanese Utility Model Laid-Open Nos. 57-134753 and 61-86833 are known.

That is, by devising the shape of the outer peripheral surface of the pinch roller, the diameter of the central portion of the pinch roller is made thicker to have a drum-shaped bulge, the contact surface with the tape is provided in the recess, and the step that serves as the tape guide is formed. It is to set up a section.

However, the technique shown in Japanese Utility Model Laid-Open No. 57-134753 and Japanese Utility Model Laid-Open No. 61-86833 is such that if the diameter of the central portion of the outer peripheral surface of the pinch roller is increased and the tape is about to come off, it will return to the center, The tape guide is provided so as to prevent the tape from slipping off, and the tape does not meander in itself, and there is a risk that the tape will wrinkle when stopped by the tape guide.

Therefore, in a tape transport device that requires stable tape running, which is used in, for example, a video tape recorder (VTR) for high-density recording, from the viewpoint of positively preventing the tape from meandering, for example, a self-aligning bearing A configuration is known in which a single columnar pinch roller is used and the pressing force on the tape is automatically adjusted.

For example, as shown in FIG. 3, the self-aligning bearing 4 is arranged in the central portion of the right columnar pinch roller 1 having no diameter difference, and the outer peripheral surface of the pinch roller 1 (the outer ring of the self-aligning bearing 4) is It can be tilted with respect to the pinch roller shaft (the inner ring of the self-aligning bearing 4).

When the pinch roller 1 is pressed by the capstan 2 via the tape, the pressing force of the portion where the pinch roller 1 contacts the tape 3 increases due to the tape thickness. Here, the force of the upper side of the pinch roller pressing the upper end of the tape is F ₁ , the distance from the center of the self-aligning bearing to the upper end of the tape is ₁₁ ,
The force that the lower side of the pinch roller presses the lower end of the tape is F ₂ ,
Set the distance from the center of the self-aligning bearing to the bottom edge of the tape.
When 1 _2, the relationship of F ₁ 1 ₁ = F ₂ 1 ₂ is established. Therefore, if the height of the tape running deviates, for example, if 1 ₁ > 1 ₂ is attempted, then F ₁ <F _{2 and} 1 ₁ = 1 ₂ is returned, so normal tape running is at the center of the pinch roller. Retained by the department.

However, for example, using a cassette tape, a small VT
In the case of forming R, it is necessary to bring the height of the pinch roller close to the tape width. For example, it may be necessary for the pinch roller to be able to penetrate part of the tape cassette. Further, as the height of the pinch roller is reduced, it is necessary to increase the hardness of the elastic body such as rubber forming the pinch roller.

In such a case, although the self-aligning type bearing was used, the pressing force near the upper end and the lower end of the pinch roller was reduced, and the pressure against the tape was not uniform. If it deviates from the vicinity, the problem of meandering occurs as in the case of the drum type pinch roller.

[Problems to be solved by the device]

In the present invention, the problems of the prior art are solved, the uniformity of the tape pressing force is not lost even when the height of the pinch roller approaches the tape width, and the tape running height deviates from the set value of the pinch roller. Even in such a case, it is an object to obtain a tape transport device that can be accurately restored.

[Means for solving the problem]

According to the present invention, in a tape transporting device that transports a tape strip sandwiched between a pinch roller composed of a columnar elastic circuit and a capstan that is a drive shaft while pressing and holding the tape, the pinch roller is attached to the shaft of the pinch roller. On the other hand, it is equipped with an automatic centering mechanism that can incline the outer peripheral surface of the pinch roller, and the diameter of the central portion of the outer peripheral surface of the pinch roller is gently smaller than the diameter of both ends (in a zigzag shape).
A tape transporting device having a pinch roller characterized by the above.

[Action]

In the present invention, since the outer peripheral surface of the pinch roller having the self-centering mechanism is formed in the stepped shape, the pressing force does not decrease near the upper end and the lower end of the tape, and the upper end of the pinch roller is Since the lower end and the lower end are always in contact with the capstan, the pressing force at the upper end of the pinch roller and the pressing force at the lower end are almost equal. Further, since no stepped portion serving as a tape guide is provided at both ends of the pinch roller, the tape is not wrinkled and the pressing force is not locally reduced. Therefore, since the tape and the pinch roller are uniformly pressed from the upper end to the lower end, the driving force of the capstan is evenly transmitted to the tape, and the tape can run stably.

It also has a restoring force when the tape running height is deviated. This is because when the tape running height is deviated in a certain direction, the direct contact area between the pinch roller and the capstan increases in the opposite direction, and the driving force of the capstan is transmitted, so that the tape is pulled back. Because.

〔Example〕

Regarding the embodiment of the present invention, first, FIG. 1 shows a side view of an elastic body constituting a pinch roller.

The upper and lower ends have the maximum diameter (actually, the chamfering is slightly chamfered so that the inside is the maximum diameter), and the diameter of the center portion of the pinch roller is smoothly reduced (in a zigzag shape).

Then, the half of the difference between the maximum diameter and the minimum diameter is named dimension L. The dimension L will be described later.

Next, the principle of the present invention will be described with reference to FIG. The same parts as those in the conventional example of FIG. 3 are given the same reference numerals, and the improved parts are given the reference numeral with A added to facilitate comparison between FIG. 3 and FIG. Pinch roller 1A with self-aligning mechanism using one self-aligning bearing 4
The tape 3 is sandwiched between the capstan 2 and the capstan 2, and is pressed and held by the elastic body of the pinch roller 1A, and the tape 3 is conveyed by the driving force generated by the rotation of the capstan 2. Here, dimensions 1 _1A from the center of the self-aligning bearing 4 to the upper end of the pinch roller 1A, also the size of to the bottom and 1 _2A, F _1A the pressing force at the upper end of the pinch roller 1A, push in the lower end If the pressure is F _2A , then F _1A 1 _1A = F _2A 1 _2A .

Usually, the tape 3 does not protrude from the pinch roller 1A, but in that case, both the upper end and the lower end of the pinch roller 1A are in direct contact with the capstan, and the tape 3 moves up and down as shown in FIG. Even if it shifts to one side, not the tape edge but the pinch roller edge is the main pressing force, so 1 _1A ≈ 1
_2A is established. Therefore, the pressing force F at the top of the pinch roller is
_1A and the pressing force F _{2A at the} lower end are almost equal.

Further, since the outer peripheral surface of the pinch roller 1A is in the shape of the hook, the pressing force does not decrease even at the upper end or the lower end of the tape. Therefore, the tape 3 is uniformly pressed from the upper end to the lower end, and the driving force of the capstan 2 is applied to the tape 3.
The tape 3 can travel without meandering.
Also, if when the tape running height became the second diagram deviates from the set value, the contact area between the capstan 2 and the pinch roller 1A in the vicinity of 1 _2A increases, capstan 2
Driving force is transmitted to the pinch roller 1A. Along with that, the lower end of the tape 3 is dragged to return to the original tape running height. It is important to return to the original tape running height instead of returning to the center of the pinch roller 1A. Actually, mount it so that the mounting height of the pinch roller 1A does not match the center of the pinch roller 1 and the tape running height. In this case, tape running is performed without meandering stably at the attached height. This has a wide tolerance of processing accuracy and mounting accuracy, and has an effect of facilitating exchange of pinch rollers for repair, for example. The restoring force when the tape running height is shifted or when the tape is shifted on a trial basis has been described by focusing on the action of the pinch roller 1A.
Since the main body of the action is running without meandering due to uniform pressing, the restoring force depends on the force to return when the balance balanced by the guide rollers (not shown) arranged before and after the pinch roller 1A is lost. However, it is also big.

Now, returning to FIG. 1, a description will be given of the dimension L indicating the amount of depression of the pinch roller in the above-mentioned claw shape. This is determined by the balance of design parameters such as the height of the pinch roller, the thickness of the tape, the width of the tape, the hardness and elastic modulus of the elastic body of the pinch roller, and the diameter of the pinch roller. The most important parameters are the tape thickness and the tape. Width.

First, the height H of the pinch roller of this embodiment can be made very close to the tape width, but it must be larger than the tape width. For example, the height H of the pinch roller can be selected to be about 22 mm for a tape width of 19 mm.

Further, the dimension L can be selected when the tape width and the height H of the pinch roller are close to each other, for example, 1.0 times or more and 2 times the tape thickness. In particular, when the tape thickness is selected to be 1.0 to 1.5 times, extremely stable tape running can be performed, tolerance to variations in pinch roller mounting height is wide, and the restoring force when the tape running height deviates is high. The original running height can be restored even if a test is performed in which the part is intentionally shifted from the upper and lower ends of the pinch roller to a position slightly protruding.

[Effect of device]

By implementing the present invention, it is possible to obtain a tape transport device that can restore the tape traveling height even when the height of the pinch roller approaches the tape width without losing the uniformity of the tape pressing force. As a result, it is possible to obtain a tape transport device that has extremely high running stability and that can perform tape running without meandering. Further, since the running stability can be kept high even when the height of the pinch roller approaches the width of the tape, it is possible to have a structure in which a part of the pinch roller can enter the tape cassette, for example, and a thin and small tape can be provided. A carrier device can be obtained.

Further, since the processing accuracy and the mounting accuracy of the pinch roller are wide, it is possible to obtain a tape transport device in which the pinch roller can be easily replaced for repair, for example. The implementation of the present invention greatly contributes to the improvement of the recording density and the downsizing of a recording / reproducing apparatus such as a video tape recorder.

[Brief description of drawings]

FIG. 1 is a side view of an elastic body constituting a pinch roller of an embodiment of the present invention, FIG. 2 is a principle explanatory view of the present invention, and FIG. 3 is a conventional self-centering type pinch roller explanatory view. 1, 1A …… Pinch roller 2 …… Capstan 3 …… Tape 4 …… Self-aligning bearing H …… Pinch roller height L …… Half the difference between the maximum and minimum diameters of the pinch roller

Claims (1)

(57) [Scope of utility model registration request] 1. A tape transporting device for transporting a band-shaped tape by pinching it with a pinch roller made of a columnar elastic rotating body and a capstan which is a drive shaft, and transporting the pinch roller by pressing. The diameter of the central portion of the outer peripheral surface of the pinch roller is made gently smaller than the diameter of both ends thereof, and the difference between the radius of both ends of the outer peripheral surface of the pinch roller and the radius of the central portion is set to the thickness of the band tape. The tape feeding device with a pinch roller is characterized in that it is 1.0 to 1.5 times as large as the above.