JP2001006628A - Coating method for electric bulb - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a uniform film thickness and decrease the number of working processes. SOLUTION: A coating is applied to the outer surface of an electric bulb having a straight tube portion (2a) in cylindrical shape through such processes that the electric bulb is lowered relatively with the forefront (2P) situated under and the base end situated over and dipped in a coating 9 contained in a coloring chamber 11, the bulb is pulled up relatively from the chamber while the pull-up speed is varied as higher in the straight tube portion and lower in the forefront part, and that the coating attached to the outer surface of the bulb is hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel method for coating a bulb. More specifically, the present invention relates to a technique for obtaining a uniform film thickness and shortening the operation time.

[0002]

2. Description of the Related Art In some cases, the outer surface of a bulb is coated.

For example, to increase the color temperature of a halogen bulb, a blue coating is applied to the outer surface of the halogen bulb.

[0004]

However, in the case where the outer surface of a bulb is conventionally coated with a coating, the film is immersed in the paint and then pulled up at a constant speed. There's a problem.

[0005] In addition, since it is necessary to secure a certain film thickness by one immersion, if the pulling is performed at a constant speed, it is necessary to select a pulling speed that is too fast for the distal end portion. However, there is a problem that the paint is accumulated and the paint must be removed. This is because, if a coating film is formed while leaving such a paint puddle as it is, the film thickness becomes too thick at the paint puddle, heat tends to be trapped during use, and peeling occurs. Therefore, if the dipping in the paint is repeated eight times, the operation of removing the paint puddle must be performed eight times, which increases the number of steps.

Accordingly, it is an object of the present invention to obtain a uniform film thickness and to reduce the number of working steps.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for coating a light bulb bulb, in which a light bulb bulb is disposed with a front end part downward and a base end part upward, relative to a coloring tank. Lower it and immerse it in the paint in the coloring tank, pull up the light bulb bulb relatively from the coloring tank while changing the pulling speed so that it is fast at the straight pipe part and slow at the tip, and then on the outer surface of the bulb bulb This is to cure the applied paint.

Therefore, in the method of coating a bulb according to the present invention, a coating film having a uniform film thickness can be obtained from the straight tube portion to the tip portion of the bulb. Also,
Since the lifting speed is reduced at the tip end, the speed can be set to a speed that does not allow the accumulation of paint, thereby eliminating the step of removing the accumulation of paint.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for coating a bulb according to the present invention will be described below with reference to the accompanying drawings.

In the following embodiment, a so-called H
The case of coating the bulb 1 called a 4-bulb will be described. The H4 bulb 1 has a glass bulb 2, a filament is arranged in the glass bulb 2, a base 3 is fixed to a base end of the glass bulb 2, and the base 3 has a flange 4. The glass bulb 2 has a cylindrical straight tube portion 2a and a front end portion 2b continuous with the front end of the straight tube portion 2a.

The straight tube portion 2 of the glass bulb 2 of the H4 bulb 1
A is provided with a blue coating 5 except for a base end portion, and a light shielding coating 6 is provided on a front end portion 2b. In particular,
First, a blue coating 5 is applied to the portion of the straight pipe portion 2a excluding the base end portion and the tip portion 2b, and then a light-shielding coating is applied from above the blue coating 5 at the tip portion 2b. The present invention is applied to a blue coating.

A jig 7 as shown in FIG.
Use The jig 7 has a large number of support holes 8 for supporting the H4 valve 1.

A paint tank 1 filled with a pigment-based blue paint 9
The coloring tank 11 is inserted in the “0”.

First, the H4 valves 1, 1,...
(See FIG. 4). At this time, the flanges 4, 4,.
Of the H4 valves 1, 1,.
Is supported in a predetermined height relationship with the jig 7.

Then, the coloring tank 11 is raised, whereby the glass bulbs 2 of the H4 bulbs 1, 1,.
Are immersed in the paint 9 in the coloring tank 11 (FIG. 5).
reference). At this time, the immersion depth of the glass spheres 2, 2,... Into the paint 9 is defined by the upper end of the coloring tank 11 being in contact with the lower surface of the jig 7.

Next, the coloring tank 11 is lowered, and
Are lifted from the paint 9 (see FIG. 6). The descending speed of the coloring tank 11 is H4 valve 1,
The lowering speed until the straight pipe portions 2a, 2a,... Of 1,... Come out of the paint 9 is faster than the lowering speed until the tip portions 2b, 2b come out of the paint. Specifically, the pulling speed of the straight pipe portion 2a is set to 1 to 10 mm / sec.
c, the lifting speed of the tip 2b is 0.2 to 2 mm / s
ec. The selection of a specific numerical value from the above numerical values is selected according to the viscosity of the coating material 9, the number of times the coating material 9 is applied, and the like.
The amount of the paint 9 adhered to the glass spheres 2 at the time of pulling up increases as the pulling speed increases, and decreases as the pulling speed decreases. Then, paint 9 on glass bulb 2 of H4 bulb 1
In the application of the paint, since the paint flows downward due to gravity, as described above, by changing the lifting speed, a uniform coating film can be obtained as a whole. In addition, by setting the pulling speed at the distal end portion 2b to such a degree that a paint puddle does not occur, the step of removing the paint puddle conventionally performed becomes unnecessary.

The viscosity of the paint 9 is 3 to 5 CP.
(Centipoise) is desirable. Viscosity is 3CP
If it is less than the above, the number of times of immersion must be increased, and if the viscosity is 5 CP or more, cracks are easily generated at the time of sintering described later.

The H4 valve 1 after the above-mentioned coating step has been completed,
Are sent to the baking step. The jig 7 is lowered, and the glass bulbs 2, 2, ... of the H4 bulbs 1, 1, ... supported by the jig 7 are heated by a heater 12 using a near-infrared dryer, a hot air dryer, or the like. 12 Where 600
The baking time is appropriately adjusted according to the type of heater used at a temperature of 670 ° C. to 670 ° C. to form the blue coating 5. Here, if the temperature is 600 ° C. or less, the sintering is not sufficiently performed, and if the temperature is 670 ° C. or more, the temperature becomes too close to 674 ° C., which is the strain point of the material glass of the glass sphere 2, and the glass The sphere may be distorted.

The steps shown in FIG. 5 to FIG.
The coating is performed once or several times until the thickness of the paint applied to the coating reaches a predetermined value, and the process of forming the blue coating 5 is completed.

Thereafter, a light-shielding coating 6 is formed on the blue coating 5 on the tip 2b of the glass bulb 2. The formation of the light-shielding coating 6 is also performed by a step of dipping the tip 2b of the glass ball 2 in a light-shielding paint and a step of firing the paint.

According to the above-described method, the formation of the blue coating 5 having a uniform thickness on the glass bulb 2 of the H4 bulb 1 can be performed at low cost.

In the above embodiment, the case where the blue coating 5 is formed on the H4 bulb has been described as an example, but it means that the bulb bulb coated by the coating method of the present invention is limited to the H4 bulb. Not something. Also, the formed coating is not limited to blue ones.

In addition, the specific shapes, structures, and methods of the respective parts shown in the above-described embodiments are merely examples of the actualization performed when carrying out the present invention, and the present invention is not limited thereto. The technical scope of the invention should not be construed as being limited.

[0024]

As is apparent from the above description, the method for coating a bulb according to the present invention is a method for coating the outer surface of a bulb having a cylindrical straight tube portion, wherein the bulb is coated at the tip. With the base part down and the base end up, it is relatively lowered with respect to the coloring tank and immersed in the paint in the coloring tank. It is characterized in that it is relatively lifted from the coloring tank while being changed, and then the paint adhered to the outer surface of the bulb is cured.

Therefore, in the method for coating a bulb according to the present invention, a coating film having a uniform film thickness can be obtained from the straight tube portion to the tip portion of the bulb. Also,
Since the lifting speed is reduced at the tip end, the speed can be set to a speed that does not allow the accumulation of paint, thereby eliminating the step of removing the accumulation of paint.

In the invention described in claim 2, the pulling speed is set to 1 to 10 mm / sec in the straight pipe portion,
Since the thickness is 0.2 to 2 mm / sec at the tip, a coating film having a uniform thickness can be efficiently formed.

According to the third aspect of the present invention, since the viscosity of the paint is set to 3 to 5 CP (centipoise), the number of times of immersion in the paint does not increase so much, and cracks occur during firing. A coating film can be formed without any problem.

According to the fourth aspect of the present invention, the paint is a pigment-based paint, and after being pulled up from the coloring tank, the paint is fired at a temperature of 600 to 670 ° C. A membrane can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of an H4 valve.

FIG. 2 is a perspective view showing a jig supporting a H4 valve and a coloring tank.

FIG. 3 is a perspective view showing a main part of the electric furnace.

FIG. 4 is an explanatory view showing a step of applying a paint together with FIGS. 5 to 7, and this figure shows a state in which the H4 valve is set on a jig.

FIG. 5 shows a state where the coloring tank is raised and the glass bulb of the H4 bulb is immersed in the paint.

FIG. 6 shows a state where the coloring tank is lowered and the H4 valve is relatively pulled up from the paint.

FIG. 7 shows a state where the jig is lowered and the glass bulb of the H4 bulb is positioned between the heaters and firing is performed.

[Explanation of symbols]

1 ... H4 bulb (bulb bulb), 2a ... straight pipe part, 2b ...
Tip part, 5 ... blue coating (coating), 9 ...
Paint, 11 ... coloring tank

Claims (4)

[Claims] 1. A method for coating an outer surface of a bulb having a cylindrical straight tube portion, wherein the bulb is lowered relative to a coloring tank with a tip end downward and a base end upward. And immersed in the paint in the coloring tank, pulling up the above-mentioned bulb bulb relatively from the coloring tank while changing the pulling speed so that it is faster at the straight pipe section and slower at the tip, then adheres to the outer surface of the bulb bulb A method for coating an electric bulb bulb, comprising curing an applied paint. 2. The method according to claim 1, wherein the pulling speed is 1 to 10 at the straight pipe portion.
mm / sec, 0.2 to 2 mm / sec at the tip
The method for coating a bulb according to claim 1, wherein: 3. The paint according to claim 1, wherein the viscosity of the paint is 3 to 5 CP (centipoise).
The method for coating a bulb according to claim 1. 4. The paint according to claim 1, wherein the paint is a pigment-based paint, and the paint is fired at a temperature of 600 to 670 ° C. after being pulled up from a coloring tank. Coating method of light bulb bulb.