JPH04195725A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain an excellent magnetic recording medium showing less missing of signal by winding the medium with a takeup roll through the process for heating the magnetic recording medium supplied from a supply roll and the process for polishing the surface of magnetic recording medium. CONSTITUTION:The surface of a magnetic recording medium 2 is polished with a sharp blade 1 and the medium is heated, by a heater lamp, from the surface of the magnetic recording medium 2 opposed to the slidable contact surface of blade 1. When the magnetic recording medium 2 is heated with the heater lamp 7, a stress accumulated within the magnetic recording medium 2 with a shape transfer is alleviated and the transferred shape can be initialized. Simultaneously, protections at the surface of the magnetic recording medium 2 can be removed by polishing the surface of magnetic recording medium 2 with the blade 1. Therefore, even when the magnetic recording medium 2 is taken up by the takeup roll 4 after these processes, since projections are already removed, the shape transfer is never generated at the surface. Thereby, the magnetic recording medium 2 which does not show any missing of signal can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium that includes a polishing step for removing protrusions present on the surface of the magnetic recording medium.

Conventional magnetic recording media may have protrusions on their surfaces due to agglomeration of dust mixed in during the manufacturing process and constituent materials of the magnetic layer and back coat. When the magnetic recording medium is used in a video tape recorder or the like, these protrusions cause dropouts and dropouts, resulting in signal dropouts on the screen. Also, in the case of digital recording devices,
This will result in a burst error. Therefore, in order to remove such protrusions, a conventional method has generally been used in which the protrusions are removed by pressing a sharp blade l against the surface of the magnetic recording medium 2 and running it as shown in FIG. ing. In addition, in the figure, 3 is a supply roll, and 4 is a take-up roll.

Problems to be Solved by the Invention However, in the conventional manufacturing method described above, when the magnetic recording medium 2 is wound up into a roll before polishing, if there is a protrusion on the surface of the magnetic recording medium 2, the protrusion is removed from the magnetic recording medium 2. The shape is transferred to other parts of the image. An example of this is shown in FIG. When there is a protrusion 5 on the surface of the n-th magnetic recording medium 2 from the center of the supply roll 3, the n+1.
n+2゜n+3. ..., the height of two surfaces of the n+nth magnetic recording medium 2 is lower than the height of this protrusion 5,
The width becomes larger than the protrusion 5, and its shape is transferred to form the protrusion 6n4-1.6n↓2.6n-3,...,6
n+n comes into being. For this reason, one protrusion 5 is transferred to a considerable extent toward the outside of the supply roll 3, as shown in the fifth figure. Therefore, there is a problem in that recording signal loss occurs due to shape transfer occurring not only on the portion of the magnetic recording medium 2 where the protrusion 5 is located, but also on the magnetic surface of the other magnetic recording medium. In addition, the surface of the magnetic recording medium 2 is touched by the blade I while the shape transfer as described above occurs.
By polishing with L, the protrusions 5 existing on the surface can be removed, but due to shape transfer, they are generated in other parts of the magnetic recording medium 2, resulting in white parts 6n+1.6n+2.6n+3.・
. . , 6n+n cannot be removed and the transferred shape remains as it is even after polishing, so there is a problem that signal loss cannot be sufficiently improved.

The present invention is intended to solve the above problems, and aims to provide an excellent magnetic recording medium with fewer signal dropouts.

! Means for Solving IB In order to achieve the above object, the present invention has the following steps: heating a magnetic recording medium pulled out from a supply roll, and polishing the surface of the magnetic recording medium, and then winding it onto a take-up roll. It is something to take.

Therefore, according to the present invention, in the step of heating the &iTt recording medium, the stress accumulated inside the magnetic recording medium caused by the shape transfer can be relieved, the stress can be restored to the shape transfer, and the stress can be removed. Since the protrusions are removed by the step of polishing the surface of the magnetic recording medium, it is possible to provide a magnetic recording medium that does not cause signal dropouts.

EXAMPLE Below, FIG. 4 together with FIGS. 1 to 3 shows a method of manufacturing a magnetic recording medium according to an example of the present invention.

Parts that are the same as those in FIG. 5 are given the same numbers, detailed explanations are omitted, and differences will be explained.

The first diagram shows the first embodiment of the present invention, in which the surface of the magnetic recording medium 2 is polished by a sharp blade 1, and at the same time the surface of the magnetic recording medium 2 is polished on the opposite side of the sliding surface of the plate 1. It is heated from the surface by the heating lamp 7 -1. When the magnetic recording medium 2 is heated by the heating lamp 7, the stress accumulated inside the magnetic recording medium 2 due to the shape transfer is relaxed, the transferred shape returns to its original shape, and the convex portion 6n+1.6n+2
゜6n+3. ..., 6n+n can be removed. At the same time, by polishing the surface of the magnetic recording medium 2 using the plate 1, the projections 5 on the surface of the magnetic recording medium 2 can be removed. Therefore, even if the magnetic recording medium 2 is wound onto the take-up roll 4 after these steps, since the protrusions 5 have been removed, no shape transfer will occur on the surface again. A magnetic recording medium 2 with fewer defects can be obtained.

This first example shows the case where only one side of the magnetic recording medium 2 is polished, but it is better to polish the opposite side of the magnetic recording medium 2 before it is wound onto the take-up roll 4. desirable.

The second example is a diagram showing a second embodiment of the present invention, in which a 1iIII polishing tape 8 was used in place of the blade l in the first embodiment to polish the surface of the magnetic recording medium 2. In order to bring the magnetic recording medium 2 and the polishing tape 8 into sliding contact, compressed air is blown from five nozzles 9 from the side of the polishing tape 8 and the side opposite to the polishing surface of the magnetic recording medium 2. Further, heating of the magnetic recording medium 2 can be carried out by preheating the air discharged from the blow nozzle 9.According to this embodiment, the magnetic recording medium 2 is heated while the abrasive tape 8 is constantly being supplied. Therefore, the magnetic recording medium 2 can be polished stably.

The third example shows a third embodiment of the present invention, in which the sliding contact position of the plate 1'1 with respect to the magnetic recording medium 2 and the heating position of the heating lamp 7 are changed. When the surface of the magnetic recording medium 2 is polished with shape transfer occurring, convex portions 6n+1
, 6n+2.6n+3°..., 6n+n may damage the surface. Therefore, only the protrusion 5 can be removed by removing the shape transfer with the heat lamp 7 and then polishing with the blade 1. .

In this way, according to the above embodiment, by providing the heating lamp 7 during the manufacturing process of the magnetic recording medium 2, the convex portion 6n+1.6n+2.6n+ whose shape is transferred by the protrusion 5 is
3. . . . can be restored based on 6n+n, and a magnetic recording medium 2 with fewer signal dropouts can be obtained.

Effects of the Present Invention As is clear from the above embodiments, the present invention can relieve the stress accumulated inside the magnetic recording medium by heating the magnetic recording medium, thereby eliminating shape transfer. Furthermore, by polishing the surface of the magnetic recording medium at the same time as or after this heating step, the protrusions on the surface of the magnetic recording medium can be removed while the unevenness caused by shape transfer is removed. Therefore, when the magnetic recording medium is wound onto a take-up roll after these steps, since the protrusions have been removed, the shape transfer will not occur again on the surface of the magnetic recording medium, and the magnetic recording medium will have less signal loss. A recording medium can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the manufacturing method of a magnetic recording medium in the first embodiment of the present invention, FIG. 2 is a schematic diagram showing the same manufacturing method in the second embodiment of the invention, and FIG. A schematic diagram showing the manufacturing method according to the third embodiment of the invention, FIG. 4 is a schematic diagram showing the conventional manufacturing method of a magnetic recording medium, and FIG. 5 shows shape transfer when there is a projection on the surface of the magnetic recording medium. FIG. 2 is a cross-sectional view of a main part of a magnetic recording medium showing a state in which this occurs. DESCRIPTION OF SYMBOLS 1... Blade, 2... Magnetic recording medium, 3... Supply roll, 4... Winding roll, 7... Heat lamp . Name of agent: Patent attorney Haruaki Ogata and two others Figure 1
f-・-go L-y 7-ne-艷take Sweat 3-4f, wear FD-1t 4・--1111 Shirilow! (Figure 2! Figure 4 D-IL9ν7I-Lll+Distribution

Claims (2)

[Claims] (1) A magnetic recording medium characterized in that the magnetic recording medium pulled out from a supply roll is wound up on a take-up roll through a process of heating the magnetic recording medium and a process of polishing the surface of the magnetic recording medium. manufacturing method. (2) The method for manufacturing a magnetic recording medium according to claim 1, characterized in that heating the magnetic recording medium and polishing the surface of the magnetic recording medium are performed simultaneously.