JPH0116107Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a heat fixing roll used in a fixing device of a dry type electrophotographic copying machine that electrostatically attaches toner to a transfer paper and develops it.

BACKGROUND TECHNOLOGY AND PROBLEMS In an electrophotographic copying machine, a toner image electrophotographically formed on a photoreceptor is transferred onto transfer paper and then fixed by a fixing device to obtain a copy. As a method for fixing the toner image, a contact heat fixing method is generally used in which a transferred transfer sheet is passed between a heat fixing roll and a pressure roll.

By the way, as shown in FIG. 2, the heat fixing roll for the above fixing device has conventionally been made of extruded aluminum with a coating layer (not shown) made of a heat-resistant release material such as silicone rubber on the surface. Shaft members 12, 12, also made of aluminum forging, are fixed to both ends of a metal cylindrical roll base 11 made of a tube or the like by welding, and a heat source such as a sheathed heater or a quartz tube heater is installed in the center. 13 is generally used. However, with such a conventional heat fixing roll,
Because there is a large space between the heat source 13 and the peripheral wall of the roll base 11, it takes a considerable amount of time for the roll to reach the specified temperature after the heater is energized, and copying operations cannot be performed after the power switch is turned on. Not only does it take a long time to start up the copying machine, but for this reason, when the copying machine is temporarily interrupted, it is necessary to leave it energized at all times without turning off the power. The reality is that there are a lot of them, and they have the disadvantage of increasing power consumption.

In addition, as a heat fixing roll that can improve heating efficiency and make the temperature distribution uniform in the longitudinal direction,
Conventionally, so-called heat pipe rollers using heat pipes have also been proposed. (For example, Japanese Patent Application Publication No. 1973-
No. 142459, JP-A-53-70444, JP-A-54-91337
No. etc.).

This heat pipe roller uses the cylindrical roller body itself as a heat pipe container, seals a working fluid as a heat medium inside, and heats it from a heat source installed inside or outside the shaft that penetrates the inside. The roller body is heated uniformly by the evaporation of the working fluid.

However, in such conventional heat pipe rollers, the cylindrical roller body itself is configured as a heat pipe container, so it is difficult to load the roller, fill it with working fluid, and completely seal both end surfaces. The heat pipe processing, which involved the following operations, was extremely troublesome. In particular, there are many sealing points required to seal both ends of the roller body, and the length is long, so in addition to the manufacturing difficulties, it may not necessarily provide sufficient security and satisfaction in terms of durability. It wasn't something.

Means for solving problems This invention is an attempt to further improve the problems mentioned above.

That is, this invention aims to eliminate the above-mentioned drawbacks while using a heat pipe with extremely high thermal efficiency to heat the roll. A heat pipe having a large number of disc-shaped fins on the outer peripheral surface is integrally provided with the fins in contact with the inner surface of the roll base, and a heat source is attached to one end of the heat pipe. The gist of the present invention is a heat fixing device in a dry type copying machine, which is characterized by having the following features.

Embodiment Referring to FIG. 1, which shows an embodiment of this invention, 1 is a metal cylindrical roll base made of an extruded aluminum tube, and 2 is a metal shaft member made of aluminum or the like welded to both ends of the base. , 3 is a heat pipe inserted into the center of the roll base 1, and has a large number of disc-shaped fins 4 on its outer peripheral surface, and the outer peripheral surface of the fins 4 is in close contact with the inner surface of the roll base 1. being in contact with Katsuko heat pipe 3
One end of the shaft member 2 passes through one shaft member 2 and projects outward, and a heat source 5 such as a sheathed heater is attached to the outer periphery of this projecting end.

The heat pipe 3 is housed in a cylindrical sealed container whose inner surface is lined with a capillary action layer.
It has a well-known structure in which a working fluid such as water that can change into two phases of gas and liquid is sealed, and by heating one end with a heat source 5, the working fluid impregnated in the capillary action layer is evaporated. , repeating the cycle of guiding the generated steam toward the other end of the closed container, which is cooled from the outside, and impregnating the working fluid obtained by condensation into the capillary action layer at the heating end. Therefore, it has the effect of transferring heat at high speed.

The fins 4 of the heat pipe 3 may be formed integrally on the outer periphery of the pipe (airtight container) by a rolling method or the like, or the fins 4 formed separately may be fixed by expanding the heat pipe. Alternatively, it may be integrally fixed to the outer periphery of the pipe by brazing.

It goes without saying that the outer periphery of the roll base 1 is provided with a coating layer made of a heat-resistant release material such as silicone rubber.

Effects of the invention Since this invention has the above-mentioned configuration, when the heat source 5 is energized, the heat generated from the heat source 5 is transferred from the peripheral wall of the container of the heat pipe 3 to the fin 4.
The temperature is efficiently and quickly transmitted to the roll base 1 through the , and the temperature can be raised to a specified temperature in a very short time. Therefore, the time required to raise the heating and fixing roll to the specified temperature can be significantly shortened compared to conventional products, and the so-called start-up time until the copying machine can be used after electricity is turned on can be shortened.
Even if the power is turned off when use is interrupted, there will be no inconvenience when reusing it, so it not only saves unnecessary power consumption when not in use, but also the power required to maintain the roll at the specified temperature during use. It also has the advantage of reducing power consumption significantly compared to conventional products.

In addition, this invention has a heat pipe 3 installed in the center of a cylindrical roll base 1 made of aluminum or the like in a shaft state via a large number of disc-shaped fins, so it is different from the conventional roll base. Compared to a heat pipe itself, there are far fewer sealing parts to form a hermetic structure, making it easier to manufacture including heat pipe processing, and improving its durability. In addition, the heat pipe 3 and the fins 4 can be easily brought into perfect contact with each other by a tube expansion method, etc.
Since the heat of the heat pipe 3 is quickly transferred to the roll base 1 through the fins 4, it is possible to quickly heat and raise the temperature of the roll surface.

[Brief explanation of drawings]

FIG. 1 is a half-cut longitudinal sectional view showing an embodiment of this invention, and FIG. 2 is a half-cut longitudinal sectional view of a conventional product. DESCRIPTION OF SYMBOLS 1... Roll base body, 2... Shaft member, 3... Heat pipe, 4... Fin, 5... Heat source.

Claims (1)

[Scope of utility model registration request] A heat pipe having a large number of disc-shaped fins on the outer peripheral surface is integrally provided in a metal cylindrical roll base with the outer peripheral surface of the fins in contact with the inner surface of the roll base, and A heat fixing roll in a dry copying machine that has a heat source attached to one end.