JPH04325920A - Coating device for magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide the coating device for production of the magnetic recording medium having particularly decreased drop-outs relating to the coating device for the coated type magnetic recording medium. CONSTITUTION:The web path between a supply section 1 and coating section 6 and the web path between a drying section 9 and a take-up section 10 of the coating device for producing the coated type magnetic recording medium installed in a clean room 12 are covered with housings 14a, 14b. Clean air is sent from a clean air supplying section 15 into the above-mentioned housings. The sticking of foreign matter on the web is prevented in this way.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for coating type magnetic recording media, and more particularly to a coating apparatus for producing magnetic recording media with less dropouts.

0002

[Prior Art] Coated magnetic recording media usually have a thickness of 4 to 7 mm.
A long film of polyethylene terephthalate or the like having a length of 5 μm and a width of 100 to 1000 mm is coated with a magnetic paint using a coating device to form a magnetic layer and, if necessary, a back coat layer, and then dried and wound up. Thereafter, the coated surface is smoothed using a calender device, and then cut into a predetermined product width using a slitter device, wound up, and placed in a tape cassette to form a product.

In recent years, with the increasing density of magnetic recording media,
Dropouts are a serious defect in product quality.
Among the causes of dropout, foreign matter on or in the magnetic layer is considered to be the most important factor.

Therefore, in the past, as shown in FIG. 2, an unwinding section 1, a dancer roll 3, a feed roll 4 which is a driving means for running the web, and a web meandering edge position control were used. - A coating device consisting of a roller 5, a coating head 6, a smoothing bar 7, an orientation magnet 8, a drying section 9, a winding section 10, and guide rolls 13 placed at key points is installed in a clean room 12 during production. Countermeasures against dropout have been taken by suppressing the adhesion of the foreign matter to the magnetic recording medium.

[0005] Furthermore, since the coated layer is in an undried state before entering the drying section 9, foreign matter is particularly likely to adhere thereto. Therefore, if necessary, by blowing clean air down from the ceiling of the coating section consisting of the coating head 6, smoothing bar 7, and feed roll 4b, so-called downflow (not shown), the magnetic Measures have been used to prevent foreign matter from adhering to the recording medium.

[0006]

[Problems to be Solved by the Invention] However, the web path from the unwinding section 1 to the coating head 6 is normally
), since it is installed under the drying section 9, it is not possible to use the down flow as described above due to space constraints and the running cost of the clean room. Further, the web path between the drying section 9 and the winding section 10 cannot be made into a down flow for the same reason.

As a result, foreign matter generated from workers working in the clean room 12 and the motor and drive belt (not shown) for driving the feed roll 4 of the device is removed from the unwinding section 1. It adheres to the film that travels along the web path leading to the coating head 6 and forms a coating film thereon, causing dropouts. In addition, foreign matter also adhered to the coated and dried tape running on the web path between the drying section 9 and the winding section 10, causing dropouts. For the above reasons, it has not always been possible to significantly reduce dropouts using conventional dropout countermeasure techniques alone.

SUMMARY OF THE INVENTION It is an object of the present invention to solve these conventional problems and provide a coating apparatus for producing magnetic recording media with less dropout.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the magnetic recording medium coating device of the present invention has a web path between an unwinding section and a coating section, and a web path between a drying section and a winding section. The web path is covered with a housing, and has a means for sending clean air into the housing, the cleanliness of the clean air is class 1 to 20, and the housing is made of stainless steel. It is characterized by certain things.

0010

[Operation] With the above-described structure, foreign matter does not adhere to the web before coating, and furthermore, foreign matter does not adhere to the web after coating and drying.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

(FIG. 1) is a side view of the coating device of the present invention, showing a dancer roll 3a, a feed roll 4a, and an edge position disposed between the unwinding section 1 and the coating head 6. The controller 5a and the dancer roll 3b are connected to the housing 14a.
It is covered with The housing 14a shown in FIG. 1 is a cross-sectional view, and openings are provided at the entrance and exit of the web 2 in the housing 14a. Further, a drive section including a drive belt and a drive motor (not shown) for the feed roll 4a is arranged outside the housing 14a, and the feed roll is attached to the housing 14a. A hole is provided through which the shaft passes, so that the feed roll 4a inside the housing can be driven by the drive section.

The edge position controller 5b, dancer roll 3c, feed roll 4c, and dancer roll 3d disposed between the drying section 9 and the winding section 10 are also similar to those described above. It is covered with a casing 14b having the structure.

Clean air blown from a clean air supply section 15 composed of a blower and a filter is sent into the housings 14a and 14b through ducts 16a and 16b and dampers 11a and 11b. Enclosure 14a,
By supplying clean air to 14b and constantly filling the enclosure with clean air, the clean room 1
The occurrence of dropouts is suppressed because foreign matter generated from workers working in the feed roller 2 and the motor and drive belt (not shown) for driving the feed roll 4 does not adhere to the film. be able to.

The material of the casings 14a and 14b is preferably stainless steel, since paint peeling may cause dropouts in painted iron plates.

Clean air to the enclosures 14a and 14b
It is preferable to adjust the supply amount of the dampers 11a and 11b so that the wind speed blown out from the openings and holes provided in the casings 14a and 14b is approximately 3 to 5 cm/sec. If the wind speed is higher than this, the running of the web will become unstable due to its influence. Further, if the wind speed is lower than the above-mentioned speed, the effect of the present invention of filling the casing with clean air is lost.

Using the coating apparatus constructed as described above, the magnetic coating liquid shown in (Table 1) was applied to a film having a thickness of 10 μm.
The coated film was coated on polyethylene phthalate, and the surface of the coating was smoothed using a calender, and then cured for a certain period of time using a curing device, and then cut into 1/2-inch widths using a slitter to produce a magnetic recording medium.

[0018]

[Table 1]

The magnetic recording medium prepared above was placed in a tape cassette, and its dropout was measured. Dropout is 10μsec, -10dB as playback output
The results of detecting objects of the above size are shown in (Table 2).

[0020]

[Table 2]

As a comparative example, a magnetic recording medium was prepared in the same manner as in the above embodiment using a conventional coating apparatus, and the dropout was measured. The results are shown in Table 2.

[0022]

As described above, the magnetic recording medium coating apparatus according to the present invention has a web path between the unwinding section and the coating section, and a web path between the drying section and the winding section. Because clean air is sent into the casing, foreign matter does not adhere to the web passing through the casing, greatly reducing dropouts of magnetic recording media, and greatly improving product quality. It was possible to improve it.

[Brief explanation of drawings]

FIG. 1 is a side view of a magnetic recording medium coating apparatus according to an embodiment of the present invention.

[Fig. 2] Side view of a conventional coating device for magnetic recording media.

[Explanation of symbols]

1 Unwinding section 2 Webs 3a, 3b, 3c, 3d Dancer rolls 4a, 4b
, 4c feed rolls 5a, 5b edge position controller 6 coating head 7 smoothing bar 8 orientation magnet 9 drying section 10 winding section 11a, 11b damper 12 clean room 13 guide roll 14a, 14b Enclosure 15 Clean air supply section 16a, 16b Duct

Claims (3)

[Claims] Claim 1: Regarding a coating device installed in a clean room for manufacturing coated magnetic recording media, a web path between an unwinding section and a coating section, and a web path between a drying section and a winding section. 1. A coating device for a magnetic recording medium, characterized in that the path is covered with a casing, and has means for sending clean air into the casing. [Claim 2] The cleanliness of the clean air is class 1 or higher.
20. The magnetic recording medium coating apparatus according to claim 1, wherein the magnetic recording medium coating apparatus is 20. 3. The magnetic recording medium coating apparatus according to claim 1, wherein the material of the casing is stainless steel.