JP2000048330A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect dirt of a magnetic head without providing a detecting mechanism newly by allowing a cleaning means to be automatically driven when an output level is judged not to be larger than a reference level by an output level judging means. SOLUTION: The signal recorded on an magnetic tape 1 is reproduced by a rotating magnetic head 2 to be inputted to a detecting circuit 3. A comparing and judging circuit 4 compares a signal level with a reference level, judges the result, and inputs the judgement result to a microcomputer 5. When the rotating magnetic head 2 is soiled, the output level of the signal is lowered and when it becomes smaller than the reference level by making the setting of the circuit 4 the reference level, the circuit 4 inputs the judgement result that the head is soiled to the computer 5, which cleans up dirt of the head 2 by pushing a cleaning roller 10 against the head 2 while driving a head cleaning mechanism 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus having a rotating magnetic head, and more particularly to a technique for cleaning a rotating magnetic head.

[0002]

2. Description of the Related Art In a conventional magnetic recording / reproducing apparatus such as a video tape recorder equipped with a head cleaning mechanism, the head cleaning mechanism is driven each time a magnetic tape is mounted or ejected.

[0003] On the other hand, Japanese Patent Laid-Open Publication No. 7-1922
In Japanese Patent Publication No. 31, a light is radiated to a gap surface of a rotary magnetic head, and reflected light from the gap surface is received by a student element to obtain a signal indicating a dirty state of the gap surface of the rotary magnetic head. Further, a configuration is disclosed in which a cleaning roller is pressed against a rotating drum in response to the detection signal.

[0004]

In the prior art configuration, the former performs head cleaning regardless of the degree of dirt on the rotary head, and the latter performs head cleaning by detecting dirt on the rotary head. There is a problem that a new optical system is required for this.

[0005]

In a magnetic recording / reproducing apparatus having a rotating magnetic head, such as a video tape recorder, an output level detecting means for detecting an output of the rotating magnetic head in order to perform auto-tracking, Some magnetic recording / reproducing devices already have output level determining means for comparing and determining output levels.

By using these means, it is possible to detect a decrease in the output level of the rotary magnetic head, and it is possible to judge the degree of contamination of the rotary magnetic head by using this.

The automatic head cleaning is driven according to the contamination. Thus, head cleaning can be performed according to dirt on the rotary magnetic head without adding a new optical system.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the basic configuration of a magnetic recording / reproducing apparatus according to the present invention, FIG. 2 is an example of an output level of a magnetic head when it is normal, and FIG. 3 is an example of an output level when the magnetic head is dirty. .

The signal recorded on the magnetic tape 1 is reproduced by the rotary magnetic head 2 and input to the detection circuit 3. The comparison and judgment circuit 4 compares and judges the signal level with the reference level, and inputs the judgment result to the microcomputer 5.

When the rotating magnetic head 2 is normal, the output level is as shown in FIG. 2. In this case, head cleaning is not required.

When the rotary magnetic head becomes dirty, the output level becomes small as shown in FIG. 3 when the magnetic head is dirty.

The setting of the comparison and judgment circuit 4 is set to a reference level 9, and when the setting is lower than the reference level 9, a judgment result of "head dirt" is input to the microcomputer 5.

In this case, the microcomputer 5 drives the head cleaning mechanism 6 and the cleaning roller 1
0 against the rotating magnetic head 2
Clean the dirt.

The detecting circuit 3, the comparing and judging circuit 4, and the microcomputer 5 can be used in common with an auto-tracking mechanism which is already employed in many video tape echoes.

[0016]

According to the present invention, it is possible to detect dirt on the magnetic head and perform appropriate head cleaning without providing a new detection mechanism.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram illustrating an example of an output level of a magnetic head in a normal state.

FIG. 3 is a diagram illustrating an example of an output level when a magnetic head is dirty.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic tape, 2 ... Rotating magnetic head, 3 ... Detection circuit, 4 ... Comparison judgment circuit, 5 ... Microcomputer,
6: Head cleaning mechanism, 7: Normal magnetic head output level, 8: Magnetic head dirty output level, 9: Reference level, 10: Cleaning roller.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toru Ishii 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi Image Information System Co., Ltd. (72) Inventor Kazuya Yamashita 1410 Inada, Hitachinaka-shi, Ibaraki Co., Ltd. Hitachi, Ltd. AV Division

Claims (2)

[Claims] 1. A magnetic recording / reproducing apparatus having a rotating magnetic head, comprising: an output level detecting means for detecting an output level of the rotating magnetic head; an output level determining means for comparing the output level with a reference level; Cleaning means for cleaning the rotating magnetic head, wherein when the output level is determined by the output level determination means to be lower than the reference level, the cleaning means is automatically driven. apparatus. 2. The magnetic recording / reproducing apparatus according to claim 1, further comprising: auto-tracking means for scanning said rotary magnetic head so as to coincide with a recording track on a magnetic tape, said output level detecting means and said output level. A magnetic recording / reproducing apparatus, wherein the determining means forms a part of the auto tracking means.