JPS59213013A - Magnetic head - Google Patents

Abstract

PURPOSE:To reduce a clogging of a magnetic head by forming a foreign matter containing recessed part either before or behind a gap of a recording medium slide-contact surface. CONSTITUTION:Recessed grooves 11, 21 are formed in the direction orthogonal to a recording medium sliding direction, on a recording medium slide-contact surface of magnetic head cores 3, 4. The recessed groove 11 does not make a foreign matter, which causes clogging of a head, pass through recording medium slide-contact surfaces 13, 14 being in the vicinity of a gap 2 of a magnetic head, and even if the foreign matter is made to pass through, it is stored by the recessed groove 21 being in the vicinity of a position where a magnetic recording medium 5 is separated in the rear, and when the magnetic recording medium 5 is rewound in the opposite direction, too, the foreign matter which causes clogging of the head is not discharged from the recessed groove 21 in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic head, such as a video magnetic head, which performs recording and reproduction by contacting a magnetic recording medium at high speed.

Conventional configurations and their problems Magnetic heads for video use are moving toward extremely improved surface roughness (fine surface roughness) as the recording density increases. As the contact area of the magnetic recording medium increases, running performance (slip) is becoming worse. In order to improve this problem, smooth materials and rust preventive agents are applied to the surface of the magnetic recording medium to improve runnability and corrosion resistance. This can be a cause of magnetic head clogging (deterioration of electromagnetic conversion characteristics, i.e., a phenomenon in which output decreases due to spacing loss or output is lost instantaneously or over a long period of time), and can be fatal due to the addition of dust and other contamination. It becomes a defect. Of course, it has a lot to do with the surface quality and shape of the head, as well as the size of the magnetic head. Therefore,
In both magnetic recording media and video magnetic heads, it is necessary to further improve the problem of head clogging.

Figure 1 shows the configuration of a conventional magnetic head. In Figure 1, arrow 1 is attached to the upper drum (omitted in the figure) of a video deck and rotates at high speed (for example, 3.75 m/Sec). This indicates the direction of rotation of the video magnetic head (rotating on the paper).
Of the magnetic head cores 3 and 4 facing the gap 2, the magnetic head core 3 has a low speed (for example, 1.08 cm7'-e
The magnetic rad core 4 comes into contact with the magnetic recording medium 5 first, which is being conveyed at a speed of c), and then comes into contact with the magnetic recording medium 5 later. It should be noted that the butter gap to which the magnetic henode core 3.4 is joined is omitted in the figure. 6 is a winding, and 7 is a hole for winding the winding 6.

First, foreign matter that can cause the head to break gathers on the recording medium sliding contact surface 13 near the gap 2 in the magnetic core 31 that contacts the magnetic recording medium 5, and then later on the magnetic recording medium 5.
Foreign matter also collects on the recording medium sliding contact surface 14 in the vicinity of the gap 2 in the magnetic head core 4 which is in contact with the magnetic head, causing a spacing loss between the magnetic head and the magnetic recording medium 5 in the vicinity of the gap 2, resulting in clogging. At this time, it becomes a fatal serious defect in that the image disappears. Therefore, there is a need to further improve the problem of head skipping in both the magnetic recording medium 5 and the magnetic head.

OBJECTS OF THE INVENTION An object of the present invention is to provide a magnetic head that can reduce clogging.

Structure of the Invention The magnetic head of the present invention is characterized in that a concave portion for accommodating foreign matter is formed at least either before or after the gap of the recording medium sliding surface.

With this configuration, foreign matter that causes clogging is accommodated in the recess, thereby reducing clogging.

DESCRIPTION OF THE EMBODIMENTS Fig. 2 shows the structure of a magnetic head according to an embodiment of the invention. The groove 11 is formed in a direction perpendicular to the sliding direction of the medium, and the groove 11 is formed closer to the gap 2 than the position 10 where the magnetic recording medium 5 starts to contact the magnetic head core 3. It is formed at a location closer to the gap 2 than the location where the recording medium 5 begins to fall from the magnetic rad core 4.
It is similar to the one shown in the figure.

With this configuration, the concave groove 11 removes foreign matter (for example, dust 1 surface-coated material, transfer of back-coated material, etc.) that becomes the original disk 1 of head clogging to the recording medium sliding contact surface 13 near the gap 2 of the magnetic head. .14 is not allowed to pass through, and even if it is allowed to pass through, the groove 21 is located near the position where the magnetic recording medium 5 leaves behind.
Similarly, when the magnetic recording medium 5 is rewound in the opposite direction after containing foreign matter in the concave groove 2, foreign matter that may cause head clogging is removed.
I am trying not to release more than 1.

FIG. 5 shows the results of measuring the number of times of clogging for each of five magnetic heads of the embodiment and the conventional example. The number of eye rolls for the examples is 5 to 15.
It was found that the number of times was 60 to 90 times in the conventional example, and the number of eye drops was less in the example. The black circles in the figure indicate the number of times each magnetic head is clogged.

Figure pf 3 shows a perspective view of another embodiment of the invention. In this embodiment, grooves 11' and 21' are formed with a cross-sectional shape of p, which is different from the grooves 11 and 21 in FIG.
The effect of reducing the sizing is the same as that shown in FIG. 2, but head processing is easier than that of the grooves 11.degree. 21 shown in FIG.

FIG. 4 shows a perspective view of yet another embodiment of the invention. In this embodiment, only the concave grooves 11 are formed, and although the effect of reducing wrinkles is somewhat lower than that of the embodiment shown in FIG. 2, the wrinkles can be sufficiently reduced compared to the conventional method.

Effects of the Invention According to the magnetic head of the present invention, since the recess is provided, foreign matter that causes clogging is accommodated in the recess, and clogging can be sufficiently reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional magnetic head, FIG. 2 is a plan view of an embodiment of the present invention, FIG. 3 is a perspective view of main parts of another embodiment of the invention, and FIG. 4 is a plan view of a conventional magnetic head. FIG. 5, which is a perspective view of a main part of yet another embodiment, is an explanatory diagram of the number of times of clogging in the embodiment of FIG. 2 and the conventional example. 2...Gap, 3...Magnetic rad core, 5...
I# Magnetic recording medium 11.21...concave grooves Fig. 4 Fig. 5

Claims (1)

[Claims] 1. A magnetic head characterized in that a recess for accommodating foreign matter is formed on at least one of the front and rear sides of the gap in the sliding contact surface of the recording medium.