JPH01264612A - Erasing head and manufacture of erasing head - Google Patents

Abstract

PURPOSE:To improve the erasing effect of a signal by causing the tape contact length of a front core part located at an upstream side to be shorter than 1.2mm as to the traveling direction in the core parts to form a gap part. CONSTITUTION:When a tape 5 travels in an arrow X1 direction, the core part at the upstream side is made into a core part 11. At the time of executing the traveling at the traveling speed of the tape 5 from 9.5cm/s to 76.2cm/s, a tape contact length l1 on the contact surface of the core part 11 is selected to be 1.2mm or below. For the case where the traveling direction of the tape 5 is changed, it is preferable that a tape contact length l3 of a core part 13 is also selected to be 1.2mm or below. On the other hand, a tape contact length l2 of a core part 12 is decided by materials to consider the magnetic characteristics of the core parts 11, 12 and 13 and by a real magnetic flux density. By such an erasing head, the erasing effect at the time of the erasing action of the signal recorded onto a recording medium can be improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an erasing head used for erasing signals recorded on a recording medium used in a tape recorder, etc., and a method for manufacturing the same. Regarding.

(Prior Art) A general problem required of an erasing head for erasing signals recorded on a recording medium, such as a magnetic recording tape, is how to improve the signal erasing effect.

This erasing effect can be confirmed by comparing the measured signal level applied to the tape before erasing with the measured signal level applied to the tape after erasing.

Many means for solving the above-mentioned general problem of erasing heads have been proposed in the past, for example, in Japanese Patent Publication No. 51-26
No. 066 and Japanese Patent Publication No. 52-29608 disclose a technique in which two gaps are provided in one erasing head in order to improve the erasing effect.

Further, Japanese Patent Publication No. 19925/1983 discloses an erasing head for multiple tracks.

By the way, in the conventional erase head as mentioned above, -7Q
It was difficult to obtain an erasing effect of d8 or higher.

In particular, erasing heads used at tape speeds exceeding 9.5 cm/s are difficult to obtain good erasing effects in frequency bands below 2KH7.

The reason for this is that the effect of the re-recording phenomenon is large at the erasing effect level of -7Qd8 or higher. Tape speed is 9
．． The gap of the erase head used in the range exceeding 5 cm/s is set after 200 μm. Tape speed is 4.
The gap of an erase head for a 76 cm/s cassette tape recorder is about 50 μm. Then, since an erasing head used in a range where the tape speed exceeds 9.5 cm/s has a wider gap than an erasing head for a cassette tape recorder, the shape of the core forming the gap also becomes larger. An erase head with a large core shape allows a large erase current to flow. However, even if an erase current higher than the current erase current is applied, the erase effect does not improve. This is because the erasing effect is not improved due to the re-recording phenomenon.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and is an erasing head used at a tape speed in the range of 9.5 cm/s to 76.2 cm/s, and particularly It is an object of the present invention to provide an erasing head that can suppress the influence of the re-recording phenomenon and reduce the deterioration of the erasing effect due to the re-recording phenomenon.

A further object of the present invention is to provide a method for manufacturing an erasing head that can efficiently manufacture the above-mentioned erasing head that exhibits an excellent erasing effect, and can also be used on recording media with multiple tracks.

[Structure of the invention] (Means for solving the problem) The invention according to claim 1 provides a tape running speed of 9.5 cm.
In the erasing head used in the range of /s to 76.2 cm/s, the tape contact length of the core part that is located on the upstream side in the tape running direction among the core parts forming the gap part is 1.2 mm. This is a shorter structure.

The invention according to claim 2 also provides a method for manufacturing an erasing head, including the steps of: arranging an arbitrary number of head bases each having a core portion including a gap portion in a polishing region in correspondence with a recording region of a recording medium; a step of storing and integrating an arbitrary number of head bases in a storage body with their polishing regions protruding from the opening; and polishing the polishing regions of the head bases protruding from the opening of the storage body to expose the gap portion. At the same time, the dimension along the running direction of the contact surface with the recording medium is 1.2 mm.
This includes a process of forming it shorter than the key.

(Function) According to the erasing head that takes the above-mentioned means, the dimension along the running force direction of the contact surface of the core part located on the upstream side in the running direction of the recording medium among the core parts forming the gap part. , 1.
Since the length is set to be shorter than 2 mm, it becomes difficult for the upstream core to reproduce the signal. As a result, during the erasing operation by this erasing head, the influence of the re-recording phenomenon is suppressed and an excellent erasing effect is exhibited.

Further, according to the manufacturing method of the erasing head of the present invention, the above-mentioned erasing head can be efficiently manufactured while maintaining high dimensional accuracy, and if the number of head bases is plural, it can have a recording area of multiple tracks. A method for manufacturing an erasing head that can perform an erasing operation on a recording medium can be provided.

(Example) FIG. 1 shows the appearance of an erasing head embodying the present invention, and FIG. 2 shows the erasing head shown in FIG.
It is a sectional view taken along -I.

1 is an erase head. The erasing head 1 is a combination of erasing heads 2, 3.4 for each track corresponding to a first track, a second track, and a third track. The erasing heads 2 and 3 are arranged vertically in a row, and the erasing head 4 fits alone but is arranged in a separate row.

The erase heads 2, 3.4 for each track are each provided with a gap 6. The caps 6 respectively cover the core parts 8, 9, .9 of the erasing head 2. '10. Core part 11゜1 of erasing head 3
2.13 and the core portion 14.15 of the erase head 4. If the tape 5 runs in the direction indicated by the arrow X1, the core parts 8, 11 and 1
4 is the core portion on the upstream side.

Moreover, if the tape 5 runs in the direction opposite to the arrow X1 direction (X2 direction), the core parts 10, 13 and 16 become the upstream core parts.

In addition, 18.19 and 20.21 in FIG. 1 are sloped portions. Core portions 8, 10, 11, 13, 14°16 are exposed on the sloped portions 18, 19, 20, 21, respectively.

Next, according to FIG. 2, the core portion 11 that contacts the tape 5,
12.13 length A1.12. Let me explain about spear 3.

When the tape 5 runs in the direction indicated by the arrow X1, the upstream core section becomes the core section 11.

The running speed of tape 5 is from 9.5 cm/s to 76.20 m.
/s, the tape contact length 11 of the contact surface of the core portion 11 is selected to be 1.2M or less. Further, in case the running direction of the tape 5 changes, it is desirable that the tape contact length 13 of the core portion 13 is also selected to be 1.2 mm or less. On the other hand, the tape contact length A2 of the core portion 12 is
It is determined by the material and the actual magnetic flux density considering the magnetic properties of 1, 12, and 13. Further, the rearward length of the core portion 11 must be 4 to ensure that the rear cross-sectional area of the core portion 11 is sufficiently large.

FIG. 3(a) shows the tape contact length of the core portions 11 and 13 shown in FIG. 2, with 1 and 12 being representative values, and the spear being 1.
It is a graph showing the erasing effect at 6#, 0.8WIM, and 0.4#.

In the graph shown in FIG. 3(a), the vertical axis represents the erasing level, the horizontal axis represents the frequency, and the tape running speed V
is constant at 76.2 cm/s.

According to the graph in FIG. 3(a), it can be seen that when 1 is 1.6 m and when 1 is 0.8 mm, 0.8 mm has a higher erasing effect at most frequencies.

Furthermore, when comparing the case where the number is 1.6# and the case where the number is 0.48, it can be seen that the erasing effect of 0.4# is higher in most frequencies.

In addition, FIG. 3(b) shows that while the tape contact length is kept constant, the tape running speed V is 76.2 cm/S.
It is a graph showing the erasing effect when changing the speed to 19.1 cm/s. According to the graph in FIG. 3(b), when the tape contact length is 0.8#, the tape speed V is 7
It can be seen that a good erasing effect is obtained when the velocity is 6.2 cm/s or less.

Next, the process of manufacturing the erasing head 1 shown in FIG. 1 will be explained with reference to FIGS. 4, 5, and 6.

FIG. 4 shows head bases 2A and 3A for each rack.

It shows the process of arranging 4A. The head base bodies (single head elements) 2A, 3A, and 4A have spacers 22,
It is superimposed with 23 and 24.

Figure 5 shows the head bases 2A for each one to rack stacked.
, 3A, 4A into a cylindrical storage body (head case) 25 having an opening 25A, and then insert each head base 2A, 3A, 4
A step of bonding and integrating A with the spacer 22.23° 2111, and each base body 2A, 3 protruding from the opening 25A.
It shows the step of polishing the ends of A, 4A and each spacer 22, 23, 24. To bond the head bases 2A, 3A, and 4A, they are inserted into the storage body 25 so that the gap 6 side shown in FIG. 4 protrudes from the opening 25A of the storage body 25 as shown in FIG. Next, adhesive is introduced from the direction shown by arrow 27. Once the adhesive has hardened, it is sanded to form a smooth curve along the tape contact surface 28, indicated by dotted line 2B in FIG. When polishing is completed, a gap 6 is exposed on the tape contact surface 2B.

FIG. 6 shows the process of shortening the length of the core portions 8, 10.11, 13, 14.16 of the erasing head 1 that come into contact with the tape 5. For this purpose, the tape contact surface 26 is ground by means of a grindstone 29 to form slopes 18.19, 20.21.

= 10- The erasing head 1 is completed by the steps shown in FIG. '19°20.21 may be precisely finished to withstand the contact running of the tape 5.

The beveled portion 19.18 may also form a groove (not shown) in the tape contacting surface 28, or this may be filled with an adhesive or the like if desired.

The present invention can be modified in various ways in addition to the embodiments described above. That is, although the erase head 1 shown in FIG. 1 is for 3 tracks, it can also be used for 1 track, 21~rack,
It can be constructed for any number of tracks, such as for 41 to racks. Further, although an example has been shown in which each erasing head 2.3.4 for each track is provided with two gaps 6, it may be provided with one gap 6 each.

[Effects of the Invention] According to the erasing head embodying the present invention, it is possible to provide an erasing head that can improve the erasing effect during the erasing operation of signals recorded on a recording medium.

Further, according to the method for manufacturing an erase head according to the present invention, it is possible to efficiently manufacture an erase head that exhibits the above-mentioned excellent erase effect, and the method can also be used for multi-rack erasing. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the erasing head according to the present invention, FIG. 2 is an enlarged sectional view taken along the knee line in FIG. 1, and FIG. 3(a)
, (b) are the frequencies of the erasing head shown in FIG.
Graphs showing erase level characteristics and FIGS. 4 to 6 are explanatory diagrams showing the manufacturing process of the erase head shown in FIG. 1, respectively. 1... Erasing head, 2, 3. =1... erasing head,
2A, 3A, 4A... Head base, 5... Tape,
6...Gi Tsubu, 3, 9.10.11.12.13.14.15.16.
...core part.

Claims (2)

[Claims] (1) Tape running speed from 9.5cm/s to 76.2cm/s
cm/s, the tape contact length of the core part that is located on the upstream side in the tape running direction among the core parts forming the gap part is 1.
．． An erasing head characterized by being shorter than 2 mm. (2) In a method for manufacturing an erasing head, a step of arranging an arbitrary number of head substrates each having a core portion including a gap portion in a polishing region in correspondence with a recording area of a recording medium; A process of storing and integrating the polishing area in a storage body with the polishing area protruding from the opening, and polishing the polishing area of the head base that protrudes from the opening of the storage body to expose the gap part and running the recording medium. 1. A method of manufacturing an erasing head, comprising the step of: forming a dimension of a surface in contact with a recording medium in a core portion corresponding to the upstream side in the running direction to be shorter than 1.2 mm.