JPS5848838B2 - Manufacturing method of heat pipe roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pipe roller 4) manufacturing method in which a heat medium is enclosed in an internal sealed space.

Since the heat hype roller has a very uniform and stable temperature distribution, its use is being considered for applications that require these characteristics, such as a fixing roller in an electrophotographic copying machine.

However, when it comes to actual application, it is difficult to realize this due to the balance with other requirements required for the roller.

For example, in the fixing roller of an electrophotographic copying machine, the roller surface is coated with a fluorocarbon resin having excellent mold releasability in order to prevent offset.

Therefore, when a heat pipe roller is used as a fixing roller, the surface of the heat pipe is coated with a fluorocarbon resin, but the temperature distribution is uniform before coating, but becomes uneven after coating.

The inventors of the present application conducted a wide range of investigations into the causes of this problem, and found that the high temperature applied to the heat pipe roller during coating generates inert gas from the internal thermal vehicle, which impairs the circulation of the heat medium vapor and causes the temperature to rise. It was found that this made the distribution non-uniform.

Among the fluorocarbon resins, Teflon (trade name, DuPont) has a melting temperature of approximately 400°C, so when a heat pipe roller is heated to this temperature for coating, the internal heating medium with a lower boiling point boils and deteriorates, producing inert gas.

This gas moves irregularly inside the roller and impedes the circulation of the heating medium vapor, resulting in an uneven temperature distribution on the roller surface.

Therefore, an object of the present invention is to provide a method for manufacturing a heat pipe roller coated with fluorocarbon resin and having a uniform temperature distribution.

A further object of this invention is to eliminate inert gas generated from a heat transfer medium during the process of coating fluorocarbon resin.
An object of the present invention is to provide the above method, which includes a step of degassing the inside of the roller.

Hereinafter, the present invention will be described with reference to the attached drawings.

FIG. 1 is a schematic diagram of a heat pipe roller manufactured by the Chiko Q invention.

The heat pipe as a heat medium container consists of an outer cylinder 1 and an inner cylinder 4 that is provided concentrically within the outer cylinder 1 and supported by side plates 2 and 3 at both ends of the outer cylinder 1. It has been.

Both ends of the inner cylinder 4 also extend from both ends of the outer cylinder 1,
In use, this part is set into the bearing part of the device.

Preferably, these members are made of a thin material with good thermal conductivity and strength, such as stainless steel.

The space 5 between the outer cylinder 1 and the inner cylinder 4 is sealed by side plates 2 and 3, and one side plate 3 has an elongated conduit 6 with an inner diameter of 1 mm or less that connects the inner space 5 of the roller with outside air. It is set up so that it can be communicated with.

The conduit 6 is shaped from a material that melts at relatively low temperatures and is easy to cut, such as copper, for ease of subsequent processing.

As shown in FIG. 2, the outer circumferential surface of the inner cylinder 4 has 7-in-8 holes to improve the circulation of the heat medium 1 that will be sealed later.
However, a plurality of them may be provided radially.

The internal space 5 of the heat pipe shaped like this is degassed from the conduit by a vacuum pump and the pressure is reduced to about 10', and then several volumes of heat medium 1 are transferred to the conduit 6. injected from.

Next, the entrance of the conduit 6 is melted and sealed using heat from a gas burner or the like.

The heat medium 7 has a temperature range of 15 in which this roller is used.
Since the temperature ranges from 0°C to 230°C, one that reaches saturation within this range is used.

For example, Neo SKOil manufactured by Nihon Soken Kagaku Co., Ltd.
170 (B.P. 180°C) is suitable for this.

After the heat transfer medium 1 is sealed, an anti-offset layer 9 is formed on the roller surface.

The anti-offset layer 9 is formed by applying liquid Teflon many times to a thickness of about 150μ, and then placing the entire roller in a furnace and heating it for a certain period of time to around 400°C, which is the melting and hardening temperature of Teflon. It is formed.

Of course, other fluorocarbon resins may be used instead of Teflon.

The heating medium inside the roller, such as the above-mentioned SK oil, has a boiling point of 180°C, so when the roller is heated to 400°C to form an anti-offset layer, the heating medium boils and a part of the assembly decomposes. to generate inert gas.

This inert gas moves inside the roller during use and prevents the normal circulation of heat medium vapor, resulting in uneven temperature distribution on the roller surface.

Therefore, in order to ensure temperature uniformity, which is an inherent characteristic of heat pipe rollers, it is necessary to expel inert gas from inside the rollers.

The removal of inert gas in this invention is carried out as follows.

First, as shown in FIG. 3, the oil 1 in the oil bath 10 is
1 is maintained at a temperature between 225° C. and 300° C., and the end of the heat pipe roller shaped as described above without the conduit 6 is immersed therein.

At this time, a portion of the offset prevention layer 9 is always immersed in the oil 11.

This causes the inert gas inside to rise, and as a result, the surface temperature of the roller decreases towards the top.

For example, four measurement points A, B zC from top to bottom
, D and measure the respective temperatures of ABC when D reaches 150℃, A: 110℃, B: 135℃
, C: 148°C.

Therefore, in this state, if part of the conduit 6 at the top of the roller is cut to open the inside of the roller to the outside air, the inert gas accumulated above the inside of the roller will escape to the atmosphere, and the temperature of the roller surface will gradually become uniform from below. .

When the temperature at each measurement point becomes uniform, for example at 150° C., the opening of the conduit 6 is again melted and closed.

The heat pipe roller formed in this way has an inner cylinder 4.
The heater 12 is set inside and completed.

As described above, the heat pipe roller manufacturing method according to the present invention includes a step of reducing the pressure in the inner space of the roller, a step of enclosing a heat medium in the inner space, a step of coating the roller surface with a fluorocarbon resin, and a step of the coating step. This process includes the step of degassing the inert gas generated from the heat medium during roller heating from inside the roller, so the finished heat pipe roller does not impair the uniformity of temperature distribution, which is the original characteristic of heat pipes. Moreover, it can be provided with functions that fully match the purpose of use.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a heat pipe roller manufactured by the method of the present invention, FIG. 2 is an end view cut along line 1-1 in FIG. 1, and FIG. FIG. 1... Outer cylinder, 2, 3... Side plate, 4... Inner cylinder, 5...
...Internal space, 6... Conduit, 7... Heat medium, 8...
-Fin, 9...Offset prevention layer, 10...Oil bath, 11...Oil, 12...Heater.

Claims (1)

[Claims] 1. A step of reducing the pressure in the internal sealed space of the roller, a step of enclosing a heating medium in the internal space, a step of coating the surface of the roller with a fluorocarbon resin, and an inertness generated from the heating medium when the roller is heated in the coating step. A method for manufacturing a heat pipe roller, including a step of degassing gas from inside the roller.