JP3074426B2 - How to apply adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of applying an adhesive, and more particularly to a method of applying an adhesive to a flange of a center core of a magnetic disk cartridge.

[0002]

2. Description of the Related Art Generally, adhesives are used in various fields to fix or join parts of various products. When a large amount of the adhesive is used, for example, in various manufacturing plants, a large amount of the adhesive is stored in an appropriate closed adhesive container or the like so as not to be hardened from the viewpoint of productivity, and the adhesive container is coated with the adhesive container. In some cases, a method is used in which a bonding apparatus is connected to an appropriate liquid feeding system, and a predetermined amount of the adhesive is discharged by pressing the adhesive in the adhesive container.

In a magnetic disk cartridge which rotatably accommodates a disk-shaped magnetic sheet as a medium for magnetic recording or reproduction, the central hole of the magnetic sheet 2 is formed in a so-called hat shape as shown in FIG. It is fitted into the center core 1 and attached to the flange portion 1a of the center core 1. In order to attach the magnetic sheet 2 and the flange portion 1a of the center core 1, a method of interposing a double-sided tape between the two or a method of using a special adhesive has been conventionally performed. In the method using a double-sided tape, the adhesive force is excellent, but the cost is high. Therefore, the adhesive is applied to the center core flange portion 1a using an application device (hereinafter, referred to as a dispenser) that discharges the adhesive from a nozzle. An annular coating method is adopted.

However, as shown in FIG. 5, when the adhesive is applied to the flange portion 1a of the center core 1, after the valve of the dispenser for quantitatively supplying the adhesive is opened, the adhesive coming out of the nozzle 3 of the dispenser is opened. the shape of the adhesive until the tip is attached to the flange portion 1a surface tends to grow gradually into spherical adhesive a ₂ from the adhesive a ₁ of the start and end with dimethyl. Therefore, the adhesive a at the application starting point
In _3, the coating width d ₁ will partially become wide, as shown in FIG. Therefore, as shown in FIG. 7, the annular coating shape after the center core 1 makes one rotation and the supply of the adhesive is stopped, even if the required coating width d ₂ is attempted.
Partially wide application width d ₁ of adhesive a ₃ at application start point
Will remain as it is.

[0005]

[0007] coating width of the annular after the adhesive application, by examining the laser beam or the like while rotating the center core 1, the inspection particularly wide ones above coating width d ₁ is At the stage, the magnetic sheet 2 is removed as a defective product, and when the magnetic sheet 2 and the center core 1 are bonded, partial protrusion of the adhesive and non-uniform bonding unevenness are avoided. However, although an increase in the amount of the applied adhesive increases the adhesive strength, the width of application at the application start point described above increases, and thus there is a problem that defective products are likely to appear. Therefore, for example, a method is conceivable in which the rotational speed of the center core 1 is controlled so as to be early in the initial stage of application and then gradually decreased, thereby preventing the partial expansion of the adhesive as described above. However, the time required for applying the adhesive is extremely short, and it is very difficult to control the rotation speed to obtain a uniform application width, so that a sufficient effect cannot be obtained, and high-precision control is required. On the contrary, there is a problem that the cost is increased by the control device and the like.

An object of the present invention has been made in view of the above-mentioned conventional problems, and provides an adhesive applying method capable of obtaining a uniform applied surface by an extremely easy applying method. It is in.

[0007]

The object of the present invention is to provide a method for applying an adhesive, wherein an annular adhesive surface is formed by dropping an adhesive from a discharge nozzle while rotating a member to be coated. A method for applying the adhesive, characterized in that the member to be applied is rotated a plurality of times to form the annular bonding surface while the position of the discharge nozzle is fixed while discharging a fixed amount of the adhesive from the substrate. can do.

[0008]

In the method for applying an adhesive according to the present invention, the member to be coated is rotated a plurality of times while the required amount of the adhesive applied to the member to be coated is kept constant. And the size of the droplet growing from the discharge nozzle can be reduced. Therefore, the application width at the application start point does not become larger than that in the conventional case of applying in one rotation, and the adhesive applied in the first rotation is spread by the adhesive to be discharged in the second and subsequent rotations, thereby providing a more uniform coating. The coating width can be set.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the method for applying an adhesive according to the present invention in which a member to be coated is rotated twice.
This will be described with reference to FIGS. The same members as those in the conventional example are denoted by the same reference numerals for convenience of explanation. FIG. 1 is an exploded perspective view of a magnetic disk cartridge 10, in which a center core 1 on which a magnetic disk 2 is integrally fitted is rotatably sandwiched between an upper half 4 and a lower half 5 made of resin. 2, a circular convex portion 1b having a rotation center shaft hole 1c and a position regulating pin hole 1d of the center core 1 is loosely fitted into the central hole 5a of the lower half 5, and the surface of the circular convex portion 1b is It is configured to be exposed on the lower surface of the lower half 5. The upper half 4 and the lower half 5 house necessary components such as the center core 1 and the like, and are welded at their peripheral edges to form an integral case.

The center core 1 is formed with a flange portion 1a. The flange portion 1a is usually made of a disc-shaped polymer film and has a flexible magnetic layer formed uniformly on the lower surface thereof. those formed for adhering the peripheral edge of the circular hole 2a provided at the center of the magnetic disk 2, the attaching is performed by adhesive a ₀ to be applied annularly the flange portion 1a.

As shown in FIG. 3, in order to supply the adhesive a onto the flange portion 1a, a dispenser 20 is used so that the supply amount is quantitatively performed. The dispenser 20 communicates or shuts off the adhesive a, which is pressure-fed from the pressure vessel 31 of the adhesive pressure-feeding device 30 via the discharge pipe 32 and the pressure-feed pipe 33, to the passage from the pressure-feed pipe 33 to the discharge nozzle 3. This is a coating device for supplying a constant amount by controlling the rotation of a rotating shaft 21 which also has a passage on the way. The rotation shaft 21 is driven by a pulse motor 23.
The driving of the pulse motor 23 is controlled by the control device 22. Further, the adhesive pumping device 30 controls the pressure in the pressure vessel 31 generated by the compressed air sent from the air compressor 34 so that the supply amount of the adhesive a per unit time is constant.

When the adhesive a is applied onto the flange 1a of the center core 1 by using the above-described coating apparatus, in the present embodiment, first, the flange 1a, which rotates horizontally at a constant speed, and the discharge nozzle 3 is 0.3 mm ± 0.1 mm (with a tolerance of ± 0.1 m).
It is desirable that m be on the plus side. ), And the amount of the adhesive a used for the center core 1 is 10 m.
g to 20 mg.

In the present embodiment, the center core 1
Since applying the adhesive a required amount of between to two revolutions, and if you now the adhesive a 10 mg used, ejecting 5 mg to 1 revolution, and then again 5 m g in the second revolution
That issue ejection. Therefore, as compared with the case of discharging 10mg in one rotation to the flange portion 1a, the adhesive agent a from 5 mg that discharged from the discharge nozzle 3 the flange portion 1a
Spherical adhesive a ₂ that grows before it adheres to the surface
Is almost halved in size.

Therefore, as shown in FIG. 4, the application width d ₁ of the adhesive a ₃ at the application start point is almost the same as the annular application width d _2, and a uniform application width can be obtained. . This is because when the clearance δ is set to 0.3 mm ± 0.1 mm and the amount of the adhesive a discharged during one rotation is reduced by half, the discharged adhesive a is almost completely reduced. It will be applied without growing as droplets.
Further, the adhesive a applied at the first rotation is spread by the adhesive a discharged at the second rotation to make the coating width and the coating thickness uniform. Therefore, in the inspection of the surface to which the adhesive a is applied, as in the conventional example, the laser beam is moved from the outer peripheral end of the flange 1a toward the center to measure the distance to the surface to which the adhesive a is applied. The inspection was conducted, and almost no defective products were repelled by the inspection.

[0015]

As described above, according to the present invention, the member to be coated is rotated a plurality of times while the position of the discharge nozzle is fixed while the adhesive is discharged from the discharge nozzle in a fixed amount, so that the unit time can be reduced. The amount of the liquid ejected from the ejection nozzle per contact is reduced, and the size of the adhesive in the form of droplets ejected from the ejection nozzle can be reduced. Therefore, the application width at the application start point does not become large as compared with the conventional case of applying by one rotation, and the variation in the application amount at the application start point of the adhesive hardly occurs. A uniform coating surface can be formed, and significant quality improvement and reduction in manufacturing cost can be achieved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetic disk cartridge in which a center core and a magnetic disk adhered according to an embodiment are mounted.

FIG. 2 is a perspective view of a center core having an adhesive applied to a flange portion.

FIG. 3 is a schematic view of an entire dispenser and an adhesive pumping device.

FIG. 4 is a plan view of a center core to which an adhesive has been applied by the application method of the present invention.

FIG. 5 is an explanatory view showing the growth of an adhesive droplet by a conventional coating method.

FIG. 6 is a plan view of a center core showing an initial stage of adhesive application by a conventional application method.

FIG. 7 is a plan view of a center core showing a completed state of adhesive application by a conventional application method.

FIG. 8 is a perspective view showing a state where a magnetic disk is attached to a flange portion of a center core.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 center core 1a center core flange 1b center core projection 1c rotation center shaft hole 1d position regulating pin hole 2 magnetic disk 3 discharge nozzle 4 cassette upper half 5 cassette lower half 5a lower half center hole 10 magnetic disk Cassette 20 Dispenser 30 Adhesive pumping device a Liquid adhesive a ₀ Adhesive applied in an annular shape a ₁ Adhesive starting from a nozzle a ₂ Adhesive grown in a sphere a ₃ Adhesion at starting point of application Adhesive δ Clearance between nozzle and flange surface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-246214 (JP, A) JP-A-63-51975 (JP, A) JP-A-63-32678 (JP, U) JP-A-6-32678 (JP, U) 102678 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05D 7/24 301 B05D 1/26 H05K 3/28 B05C 5/00 101

Claims (1)

(57) [Claims] 1. A method of applying an adhesive by forming an annular bonding surface by dropping an adhesive from a discharge nozzle while rotating a member to be coated, wherein the discharge nozzle discharges a predetermined amount of the adhesive while discharging the adhesive from the discharge nozzle. The method of applying an adhesive, wherein the member to be applied is rotated a plurality of times while the position of the nozzle is fixed to form the annular adhesive surface.