JP7037722B2 - Molding method for filament lamp and tip tube residue - Google Patents

Description

The present invention relates to a filament lamp having a tip tube remnant in an arc tube and a method for forming the tip tube remnant thereof.

Conventionally, an image forming apparatus of a printer or a copying machine is equipped with a fixing device for heating and fixing toner on a recording medium. This fixing device includes a heat roller that rotates in one direction and a pressure roller that abuts on the rotating surface of the heat roller, and a filament lamp that heats the heat roller from the inside is arranged inside the heat roller. Has been done. Then, the toner image is fixed on the recording medium under heating and pressurization by passing a recording medium carrying the toner image through the contact surface between the heat roller and the pressure roller.

In this way, the heat roller is heated by the light energy from the lamp mounted inside, and the ink is fixed via the heat roller. At this time, if the heating efficiency of the heat roller is low, the temperature rise time of the heat roller until the start of use becomes slow, and the start-up time of the device required to shift to the steady heating state becomes long. Therefore, it is necessary to make the heat roller smaller and improve the heating efficiency.
For example, Japanese Patent Application Laid-Open No. 2006-184719 (Patent Document 1) describes a configuration in which a lamp is mounted inside a heat roller, and at that time, the position of the remaining tip tube (tip portion) is adjusted. Is described.

However, the configuration described in Patent Document 1 merely defines a preferable position of the tip portion when mounting the two filament lamps, and as shown in FIG. 6, the tip tube remaining portion 13 (hereinafter, simply chip) is defined. The part) itself has a structure that greatly protrudes (L) from the outer surface of the arc tube 11. Therefore, it is not a fundamental solution to the problem that the chip portion 13 hinders miniaturization.
Further, the chip portion 13 is formed in a part of the arc tube 11 in the longitudinal direction, and as described in Patent Document 1, the tip portion 13 has a shape that greatly protrudes outward from the arc tube 11. The light from the filament 12 is refracted by the chip portion 13, and the heat distribution in the longitudinal direction and the circumferential direction of the filament lamp is deteriorated. That is, there is a problem that the temperature tends to drop around the chip portion 13 and local fluctuations in radiant heat (hereinafter referred to as ripples) are formed in the heat distribution in the longitudinal direction and the circumferential direction of the arc tube 11.

Various studies have been made so far on how to solve such problems in the chip portion.
For example, Japanese Patent Application Laid-Open No. 02-056846 (Patent Document 2) proposes a measure for denting the periphery of the sealed end of the tip portion so that the protruding tip portion does not come into contact with the instrument and be damaged. ..
However, by forming a dent in the arc tube, a convex portion protruding inward of the arc tube is formed. This convex portion is close to the filament (heating element) in the arc tube, and there is a problem that the heat load from the filament is excessively applied. This problem becomes apparent especially when the outer diameter of the filament lamp is designed to be small.

Further, Japanese Patent Application Laid-Open No. 2013-246970 (Patent Document 3) describes molding a filament lamp that does not use an exhaust pipe (chip tube). However, as described in the present document, the lamp having no chip portion has a problem that the life characteristic is worse than that of the filament lamp having the chip portion due to the problem in the process.

Japanese Unexamined Patent Publication No. 2006-184719 Japanese Patent Application Laid-Open No. 02-056846 Japanese Unexamined Patent Publication No. 2013-246970

The problem to be solved by the present invention is to eliminate the hindrance of miniaturization of the heat roller due to the remaining tip tube in the filament lamp having the filament inside the arc tube and the remaining tip tube on the outer surface of the arc tube, and to emit light. It is an object of the present invention to provide a lamp structure having good life characteristics by avoiding illuminance non-uniformity in the axial direction and the circumferential direction of the tube as much as possible.

In order to solve the above problems, the filament lamp of the present invention is characterized in that the remaining portion of the tip tube has a flat curved surface shape along the outer surface of the arc tube in the circumferential direction.
Further, the remaining portion of the chip tube is characterized in that the thickness thereof is 20% or less with respect to the outer diameter of the arc tube.
Further, in the method for forming the remaining portion of the tip tube, a step of heating and melting the root of the tip tube attached to the outer surface of the arc tube and welding, and a step of pulling up and detaching the tip tube are separated. It is characterized by a step of pressing a molding jig having a concave molding surface on the lower surface against the remaining portion of the chip tube remaining in the arc tube.

According to the present invention, the chip tube balance formed on the outer surface of the arc tube has a flat curved surface shape that follows the curved surface shape of the arc tube, so that the tip tube balance does not protrude much from the outer surface of the arc tube. When arranged in the heat roller, the size of the heat roller can be reduced without interfering with the heat roller.
Since the remaining tip tube does not protrude into the arc tube, a narrow region is not locally formed in the inner diameter of the arc tube.
In addition, since the rest of the chip tube has a flat shape, refraction of light from the filament is suppressed, and a good illuminance distribution in the axial direction and the circumferential direction can be obtained in the illuminance distribution of the light from the arc tube. The formation can be suppressed.

Partial perspective view of the filament lamp of this invention. FIG. 1A is a cross-sectional view taken along the line AA of FIG. Explanatory drawing of the molding method of a chip part. A molding jig used for molding chips. A table showing the effect of the present invention. Sectional view of the prior art.

FIG. 1 is a partial perspective view of the filament lamp 1 of the present invention, in which the coil-shaped filament 3 is arranged inside the arc tube 2 having a circular cross section.
The chip tube balance (chip portion) 4 is formed on the outer surface of the arc tube 2. As shown in FIG. 2, the chip portion 4 has a flat shape as a whole, and has a curved surface shape so as to be in contact with the chip portion 4 along the outer surface in the circumferential direction of the arc tube 2. Has been done.
With such a shape, it is possible to secure the mechanical strength while keeping the height of the chip portion 4 low. Further, a region where the inner diameter of the arc tube 2 is locally narrowed is not formed. Further, since the chip portion 4 has a flat shape along the outer surface of the arc tube 2, the refraction of light from the filament 3 is suppressed, and the light distribution (heat distribution) of the filament lamp 1 is localized in both the axial direction and the circumferential direction. It is suppressed to make it worse.

FIG. 3 shows a method for forming such a tip tube balance (tip portion).
Although not shown in FIG. 3, the arc tube 2 in which the filament 3 is arranged is sealed at both ends thereof. An exhaust pipe (chip tube) 5 is attached to the arc tube 2, and the impure gas in the arc tube 2 is exhausted and the filling gas is filled through the tip tube 5.
After that, as shown in FIGS. 3A and 3B, the root portion of the chip tube 5 is heated and melted by an oxyhydrogen burner 6 or the like to be sealed, and the inside of the arc tube 2 is sealed. As shown in FIG. 3C, the chip tube 6 is pulled up and detached (chip off) after sealing to form the chip tube remaining portion (chip portion) 4 on the arc tube 2 side. Then, by pressing the molding jig 7 against the chip portion 4 that is still in a molten state, the chip portion 4 is molded into a desired shape.

The shape of the forming jig 7 is shown in FIG. 4, and the forming jig 7 has an arcuate concave forming surface 8 on the lower surface thereof, and as shown in FIG. 3D, this forming is performed. The surface 8 is pressed against the chip portion 4 so as to coincide with the circumferential direction of the outer peripheral surface of the arc tube 2.
Thus, as shown in FIGS. 1 and 3D, the chip portion 4 has a flat shape as a whole, and has a shape along the outer peripheral surface of the arc tube 2 in the circumferential direction and abutting on the outer peripheral surface thereof. It has a curved surface shape.
It is desirable that the height (thickness) of the flat tip portion 4 is within 20% of the outer diameter of the arc tube 2. As a result, the tip portion 4 does not get in the way when the filament lamp is mounted in the heat roller having a small inner diameter, the mounting work becomes easy, and the tip portion 4 is not damaged.

A specific embodiment of the arc tube and the chip portion is as follows with reference to FIG.
・ Outer diameter of arc tube: D = φ6.0 mm
-Tip thickness: T = 1.5 mm or less (preferably 1 mm or less)

An experiment was conducted to demonstrate the effect of the present invention.
As a comparative example of the conventional chip shape as shown in FIG. 6, the ripple rate was compared with that of the chip shape of the present invention.
The heat distribution was compared in the axial range of ± 10 mm with the center position of the chip set to 0 mm. The result is shown in the graph of FIG.
Ripple rate of comparative example 26.5%
Ripple rate of the present invention 13.9%
Ripple reduction rate (invention / comparative example) = 52.6%
The ripple rate was calculated by (maximum-minimum) / average × 100% in the range of ± 10 mm.
As mentioned above, the ripple rate could be reduced to about half.

As described above, in the filament lamp of the present invention, the chip tube balance formed on the outer surface of the arc tube has a flat curved shape along the outer surface in the circumferential direction of the arc tube, so that the outer circumference of the arc tube is formed. The amount of protrusion from the surface is small, and when it is inserted into the heat roller, the tip portion does not get in the way, which contributes to the miniaturization of the heat roller.
In addition, since it has a flat shape along the circumferential direction of the arc tube, refraction of light from the arc tube is suppressed, and the light distribution (heat distribution) of the filament lamp is locally deteriorated in both the circumferential direction and the axial direction. Is suppressed.

1: Filament lamp 2: Light emitting tube 3: Filament 4: Tip tube rest (tip part)
5: Exhaust pipe (tip pipe)
6: Oxyhydrogen burner 7: Molding jig 8: Molding surface D: Outer diameter of arc tube T: Thickness of tip

Claims (3)

In a filament lamp having a filament inside the arc tube and having a chip tube residue on the outer surface of the arc tube.
The filament lamp is characterized in that the remaining portion of the chip tube has a flat curved surface shape along the outer surface of the arc tube in the circumferential direction. The filament lamp according to claim 1, wherein the remaining portion of the chip tube has a thickness of 20% or less with respect to the outer diameter of the arc tube. The process of heating and melting the root of the chip tube attached to the outer surface of the arc tube and welding it.
The process of pulling up and detaching the tip tube and
The method for forming a chip tube residue in a filament lamp according to claim 1, further comprising a step of pressing a forming jig having a concave forming surface on the lower surface against the chip tube remaining portion that is detached and remains in the arc tube.

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