JPH01320634A - Calender device for magnetic recording medium - Google Patents

Abstract

PURPOSE:To use a calender roll for a long time without grinding or cleaning by interposing a calender belt between the magnetic layer surface and the calender roll of a magnetic recording medium. CONSTITUTION:A first calender belt 9 coiled by a belt coiling roll 8 and sent from a belt sending roll 7 is interposed between a metallic roll 2 and a magnetic layer surface 1b of a magnetic storing medium 1 and it is travelled between the roll 2 and the medium 1 at the constant velocity with the medium 1. On the other hand, at an elastic roll 3 and a non-magnetic supporting body surface 1a of the medium 1, a second calender belt 12 coiled to a belt coiling roll 11 and sent from a belt sending roll 10 is interposed and travelled between the roll 3 and the medium 1 at the constant velocity with the medium 1. Consequently, both surfaces 1a and 1b pass through between respective rolls, are smoothed in a surface shape in accordance with the surface roughness of belts 9 and 10, and the transfer of the dirt and the scratch of the surface of the rolls 2 and 3 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a calendering device for magnetic recording media, and more particularly, to a calendering device for magnetic recording media that can process the magnetic recording media so that both the front and back surfaces are in good condition. This invention relates to a calendar device.

(Prior Art) Generally, in the manufacturing process of a magnetic recording medium, a magnetic coating liquid containing magnetic particles (magnetic powder) and a binder is coated on a non-magnetic support to form a magnetic layer. After an orientation treatment or the like is performed as necessary, the magnetic layer is dried, and then a calender treatment is performed to smooth the surface of the magnetic layer.

As shown in FIG.
3, this is generally carried out by holding and transporting the web-shaped magnetic recording medium 101 while pressurizing and heating it. The metal roll 102 is a roll made of a metal such as 545C plated with hard chrome or the like, and its surface is mirror-finished. One elastic roll is made by fitting an outer peripheral part made of cotton, nylon, etc. to a roll core made of metal such as 8450, and polishing the surface to a predetermined surface roughness. Magnetic recording medium 1
01, the magnetic layer surface 101a is on the metal roll 102,
The non-magnetic support surfaces 101b are made to run in contact with the elastic rolls 103, respectively.

However, in a calender device in which an elastic roll is used together with a metal roll as described above, the surface of the elastic roll tends to become brittle due to the heat and repeated stress during calendering, and the brittle surface of the elastic roll becomes attached to the non-magnetic support. It may be transferred to the surface, significantly deteriorating the quality of the surface. Furthermore, if dirt adheres to the surface of the elastic roll, this dirt is also transferred to the surface of the nonmagnetic support. In order to prevent such transfer and transfer, it is necessary to frequently polish the surface of the elastic roll, which poses a problem of lowering the processing efficiency of the apparatus.

Therefore, in order to prevent the surface of the elastic roll from becoming brittle or getting dirty, an elastic tape is interposed between the elastic roll and the magnetic recording medium, and the magnetic recording medium is calendered between the elastic tape and the metal roll. (Unexamined Japanese Patent Publication No. 49-11108)
An apparatus for calendering the web between the metal belt and the metal roll by interposing a metal belt between the coal and the web has already been proposed (Japanese Patent Laid-Open No. 54-46264). According to these devices, since the elastic roll does not come into direct contact with the magnetic recording medium, it is possible to avoid the adverse effects of deterioration or staining of the elastic roll on the surface of the non-magnetic support of the magnetic recording medium.

(Problem 8 to be solved by the invention) In recent years, magnetic recording media have been required to have performance that enables high-density recording and high output, and in order to provide such performance, it is necessary to improve the magnetic layer surface of the magnetic recording medium. A high degree of smoothing is required. In order to highly smooth the surface of the magnetic layer, it is necessary to increase the pressure applied by the calender roll and the heating temperature, and to reduce the transport speed of the magnetic recording medium. For this reason, dirt and scratches are likely to occur on the surface of the metal roll, which has not caused any particular problems in the past.

If dirt or scratches occur on the metal roll, these will inevitably be transferred to the magnetic recording medium, and since the metal roll will be in contact with the surface of the magnetic layer where information is recorded and reproduced, the above transfer will depend on the quality of the calendered medium. This will result in significant damage to the

Therefore, in a calender device that highly smoothes a magnetic recording medium, the surface of the metal roll also needs to be frequently polished or cleaned, which is disadvantageous in that efficient processing cannot be performed.

At the same time, in conventional calendering devices, in order to change the finished smoothness of the magnetic layer surface of the medium,
Each time, the metal roll had to be replaced with a roll having a different surface roughness, which caused the problem of poor work efficiency.

The present invention has been made in view of the above-mentioned problems, and it is possible to use any calender roll such as an elastic roll or a metal roll for a long period of time without polishing or cleaning, and it is possible to use a calendar roll without polishing or cleaning. It is an object of the present invention to provide a calendar device for magnetic recording media that can easily change the state.

(Means and Effects for Solving the Problems) A calendering device for a magnetic recording medium of the present invention includes a plurality of calender rolls, and a magnetic Calendar belts are interposed between the surfaces of the magnetic layers of the recording medium, and the calender roll smoothes both surfaces via these calender belts.

The calender roll may be composed of a metal roll and an elastic roll as in the conventional apparatus described above, or may be entirely metal rolls or ceramic rolls such as zirconia. Furthermore, since the above two calender belts are used to polish the surface of the magnetic recording medium in place of the calender roll, they both need to have a surface roughness suitable for calendering, and must have a surface roughness suitable for calendering. The contact surface of the calender belt has a surface roughness R.
a is 0.005 to 0.03 μm (cutoff value 0.2
5m11), and the calender belt in contact with the surface of the non-magnetic support has a surface roughness Ra of 0.5m11). O1~0.0
It is desirable to be in the range of 8 μm (cutoff value 0.25+am).

If both sides of the magnetic recording medium are pressurized by the calender rolls via the calender belt, when an elastic roll is used as the calender roll, the surface of the elastic roll will be less likely to become brittle, and the calender roll will Adhering dirt and scratches are no longer transferred not only to the surface of the non-magnetic support of the medium but also to the surface of the magnetic layer. In addition, if you want to adjust the surface condition of the magnetic layer surface by calendering, you only need to replace the calender belt between the magnetic layer surface and the calender roll, which is much easier than replacing the calender roll that contacts the magnetic layer. Sexuality is greatly improved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a schematic side view of a calendar device according to an embodiment of the present invention.

A web-shaped magnetic recording medium, which is formed by applying a magnetic coating liquid or the like to the surface of a non-magnetic support to form a magnetic layer, is fed out from a medium delivery roll 4 and is moved vertically. Metal rolls 2 arranged alternately
and the elastic roll 3. The magnetic recording medium 1 is arranged with the magnetic layer surface 1b facing the metal roll 2 and the non-magnetic support surface 1a facing the elastic roll 3, and the magnetic recording medium 1 that has been calendered is placed in the media roll. It is sequentially wound up by a take-up roll 5. Note that the roll indicated by 6 in the figure is a pass roll that brings the magnetic recording medium 1 and first and second calender belts, which will be described later, into contact directly or indirectly with the metal roll 2 and the elastic roll 3 at a predetermined wrap angle.

A first calendar belt 9 is interposed between the metal roll 2 and the magnetic layer surface lb of the magnetic recording medium, which is wound up by a first belt take-up reroll 8 and sent out from a first belt delivery roll 7. The magnetic recording medium 1 is moved between the metal roll 2 and the medium 1 at the same speed as the magnetic recording medium 1. Therefore, the magnetic layer surface 1b is smoothed into a surface shape corresponding to the surface roughness of the first calender belt 9 by passing between the respective rolls. This first calender belt has a thickness of 0.03 to 1.0 am and a width of 100 mm.
Although it is made of a metal belt such as a thin stainless steel plate of ~2000+++s or a polymer film such as polyethylene terephthalate, it is preferable to use a metal belt if the surface of the magnetic layer is desired to be smoothed to a higher degree. On the other hand, between the elastic roll 3 and the non-magnetic support surface 1a of the magnetic recording medium, a second calendar belt 12 is wound around the second belt winding roll 11 and sent out from the second belt delivery roll 10. is interposed and is caused to run between the elastic roll 3 and the medium 1 at the same speed as the magnetic recording medium 1.

Therefore, the non-magnetic support surface 1a passes between the respective rolls, thereby forming the second calender belt 12.
The surface is smoothed according to the surface roughness of the surface.

The thickness and width of the second calender belt are the same as those of the first calender belt, and the material thereof is also made of a metal belt such as a thin stainless steel plate or a polymer film such as polyethylene terephthalate.

When calendering the magnetic recording medium 1 in this way,
If the second and first calender belts 9.12 are brought into contact with the non-magnetic layer surface 1a and the magnetic layer surface lb of the medium, respectively, both surfaces will not come into direct contact with the metal roll 2 or the elastic roll 3, so that the elastic roll It is possible to prevent the surface from becoming brittle and also to prevent stains and scratches from being transferred to the surface of the elastic roll and metal roll. Moreover, the surface condition of the finished surface of the magnetic recording medium can be changed very easily by simply replacing the first and second calender belts with those having a desired surface condition. Furthermore, since the metal roll and the elastic roll do not come into direct contact with the medium 1, the surface finish of both rolls may be slightly rougher than before.

Note that the first and second belt delivery rolls 7.10
, the first and second belt winding rolls 8.11 are each reversible, and the first and second calender belts 9.12 are all wound around the first and second winding rolls 8.11. Once removed, both belts can be rewound onto the first and second belt delivery rolls 7.10 for repeated use. Furthermore, if cleaning means such as non-woven fabric is provided at a position in contact with each belt, the number of times the belt can be used repeatedly can be increased.

Further, the first calender belt and the second calender belt do not necessarily have to be one each as in the above embodiment, and as shown in FIG. 2, for each metal roll 2 and elastic roll 3, One each, independent delivery rolls 7A, 7B, 11, take-up rolls 8A, 8B, 12
The first calender belts 9A, 9B,
Alternatively, a second calendar belt 12 may be provided. In this case, not only can each belt be replaced more easily, but also the surface shape can be made different for each belt, which increases the flexibility of the calendering process.

(Example) Examples of the present invention will be further described below.

25cc/rr of magnetic coating liquid etc. is applied onto a polyethylene terephthalate base with a thickness of 15μm and a width of 300mm. The coated, oriented, and dried web-like magnetic recording medium was heated at a linear pressure of 200 kg each in the calender device shown below.
/c+++, temperature 80'', conveyance speed 100 m/ll1
Calendar treatment was carried out under the conditions of n.

(Example 1) In the apparatus shown in FIG. 1, 545 metal rolls were used.
Hard chrome plating is applied to the roll body of C, outer diameter 200 mm, length 400 ff, 11% surface roughness Ra
Using a roll with a diameter of 0.050 μm, as an elastic roll,
A roll made by fitting a 345C roll core into a nylon tube, with an outer diameter of 300 ml, a length of 350 rats, and a surface roughness Ra of o and oeoμm, was used as the first calender belt, and a roll with a thickness of 0.1 mm and a width of 0.1 mm was used as the first calender belt. A stainless steel thin plate with a thickness of 400 mm, a surface roughness Ra of the surface in contact with the magnetic recording medium of o, and oto μm was used as the second calender belt, a thickness of 0.05 + n, a width of 400 mm, and a surface roughness of the surface in contact with the magnetic recording medium. Calendering was performed using a polyethylene terephthalate film with an Ra of o and oao μm.

(Comparative Example 1) The first calender belt was removed from Example 1, and the calender treatment was performed under all other conditions.

(Comparative Example 2) Calendering was performed by removing the second calender belt from Example 1 and keeping all other conditions the same.

(Comparative Example 3) In the apparatus shown in FIG. 3, the metal roll was made of
The dimensions are the same as the metal roll of Example 1, and the surface roughness R
a is 0.010 um (cutoff value 0.25 mm)
The elastic roll was made of the same material and dimensions as the elastic roll of Example 1, and had a surface roughness Ra of 0.0.
Calendering was performed using a roll of 30 am (cutoff value 0.25+nm).

For Example 1 and Comparative Examples 1 to 3 described above, the magnetic recording medium was L(1, (toom, 20; 0(1
(1m.

50,000 m, 1 (At the stage of processing 10,000 m, the surface roughness of the magnetic layer surface, nonmagnetic layer supporting surface, metal roll surface, and elastic roll surface of the obtained magnetic recording medium was M
) has been established. Note that in both cases, cleaning of each roll was not performed during the process. The obtained results are shown in the table below. As is clear from the results above, in Comparative Examples 1 to 3, the calendar belt was not in contact with the roll (metal roll in Comparative Example 1, elastic roll in Comparative Example 2, The surface smoothness of the metal rolls and elastic rolls in Comparative Example 3 deteriorates due to dirt and the like as the treatment continues, and as a result, the surface smoothness of the media in contact with these rolls (the magnetic layer surface in Comparative Example 1,
In Comparative Example 2, the smoothness of the non-magnetic support surface (in Comparative Example 3, both sides) also deteriorated, whereas in Example 1, the surface roughness of each calender roll was maintained uniformly over a long period of time, It was confirmed that good calendering could be carried out permanently.

(Effects of the Invention) As explained above, according to the calendering device for a magnetic recording medium of the present invention, a By interposing the calender belt, highly accurate calendering can be performed for a long period of time without cleaning or polishing the calender roll, and the smoothness of the surface of the magnetic layer can be improved. Furthermore, since the calender belt can be easily replaced with one having a different surface roughness, the calender state of the medium can be easily changed.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a calendar device for magnetic recording media according to an embodiment of the present invention, FIG. 2 is a schematic side view of a device according to another embodiment of the present invention, and FIG. 3 is a schematic side view of a conventional calendar device. FIG. 1...Magnetic recording medium 1a...Nonmagnetic support surface ■b...Magnetic layer surface 2...Metal roll 3...Elastic roll 9...First calender belt 12...No. Figure 1 of 2 calendar belt

Claims (1)

[Claims] A web-like magnetic recording medium having a magnetic layer formed on a non-magnetic support is passed between a plurality of calender rolls arranged parallel to each other and adjacent to each other. In a calendering device for a magnetic recording medium that performs smoothing treatment on the surface of the non-magnetic support and the surface of the magnetic layer, between the calender roll and the surface of the non-magnetic support, and between the calender roll and the surface of the magnetic layer. 1. A calendering device for a magnetic recording medium, characterized in that a calender belt is interposed between each of the magnetic recording media, and the calender roll performs the smoothing process via these calender belts.