JPS5933474A - Fixation roll for copying machine - Google Patents

Abstract

PURPOSE:To enhance the mechanical strength of a body and shorten the warm- up time, by forming a slit throughout the overall length of a reinforcing metallic cylinder in the axial direction and arranging an induction coil concentrically into the body where a thin heating metallic cylinder is fitted around this reinforcing metallic cylinder. CONSTITUTION:A linear slit 4 is formed throughout the overall length of a reinforcing metallic cylinder 2 in the axial direction of the cylinder so that an induced current is not flowed into the cylinder 2 by the magnetic field generated by an induction coil 3. Many recessed grooves 5 extending in the circumferential direction of the cylinder 2 are formed in parallel in the axial direction of the cylinder 2 in all regions of the outside circumference of the reinforcing metallic cylinder 2 for the purpose of preventing the heat conduction from a heating thin metallic cylinder 1 to the reinforcing metallic cylinder 2, and the heat conduction from the heating metallic cylinder 1 to the reinforcing metallic cylinder 2 is stopped by air in recessed grooves 5. Thus, the mechanical strength of the roll body is enhanced, and the warm-up time is shortened.

Description

[Detailed description of the invention] Industrial applications This invention relates to a fixing roller for copying machines.

Conventional configuration and problems The heat fixing method of electrostatic plain paper copiers generally uses a halogen lamp as the heat source, but this method uses heat conduction through side radiation and convection. Since the fixing roller is heated by heating, there is a drawback that it takes a long time to reach a predetermined humidity (hereinafter referred to as warm-up time). As a method to compensate for this drawback, a method has been proposed in which a high e-induced current is passed through the fixing roller and the resulting Joule heat is used as a heat source.

FIG. 1 shows the relationship between the wall thickness of a metal roller and the warm-up time when a constant high-frequency power is applied to the metal roller with the same external dimensions. It can be seen from FIG. 1 that the smaller the thickness of the metal roller, the shorter the warm-up time. However, this metal roller is required to have a certain mechanical strength as a fixing roller, so if we take a metal roller made of stainless steel as an example, it will have at least Q, 51
It is considered that 81 or more is necessary. In other words, with conventional metal rollers, if the wall thickness is made thinner to shorten the warm-up time, the mechanical strength will be insufficient; conversely, if the wall thickness is made thicker to ensure mechanical strength, the warm-up time will be reduced. It had the problem of being long.

OBJECTS OF THE INVENTION An object of the present invention is to provide a fixing lobe for a copying machine that can shorten warm-up time while ensuring mechanical strength.

Structure of the Invention The fuser lobe for a copying machine of the present invention has a reinforced metal cylinder in which a slit is formed over the entire length in the cylinder axis direction, a thin heated metal cylinder is fitted onto the outside to form a lobe body, and an induction coil is inserted into the lobe body. are arranged concentrically, and when the induction coil is energized, an induced current is induced only in the thin-walled heated metal tube, and the heated metal tube is heated by the Joule heat, and the heated metal tube is reinforced with a reinforcing metal tube. It is.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 to 5. FIG. 2 shows a sectional view of this embodiment. Reference numeral 1 denotes a thin-walled heating metal cylinder made of metal such as aluminum, iron, stainless steel, etc., and 2 a reinforcing metal cylinder for reinforcing the thin-walled heating metal cylinder 1. Further, 3 indicates an induction coil for flowing high frequency current. FIG. 4 shows the disassembled state of the thin-walled heating metal tube 1 and the reinforcing metal wJ2, viewed from the side. In particular, the reinforcing metal tube 2 is
Furthermore, the following processing is required. In other words, as part of the processing, reinforcing metal ff? In order to prevent the force-induced current l (flowing in the circumferential direction of the reinforcing metal cylinder 2) from flowing in I2 due to the magnetic field generated by the induction coil 3 as shown in Fig. 4, a linear slit 4 is formed along the entire length in the cylinder axis direction. . -1, from the thin-walled metal tube 1 that generates heat to the reinforced metal tube 2
In order to prevent heat conduction to the cylinder, as shown in FIG. 3, a large number of grooves 5 extending in the circumferential direction of the reinforcing metal cylinder 2 are formed in parallel in the cylinder axis direction over the entire outer circumferential surface of the reinforcing metal cylinder 2. When the thin heating metal tube 1 is fitted onto the reinforcing metal tube 2 to form the lobe body 6, the air in the groove 5 prevents heat conduction from the metal tube 1 to the metal tube 2. As a result of this configuration, when a high-frequency current is applied to the induction coil 3, the induced current induced in the reinforcing metal cylinder 2 is blocked by the slit 4, and therefore a high-frequency induced current is induced only in the heating metal cylinder 1. The heating metal tube 1 is heated by the heating metal cylinder 1, and since the heating metal cylinder 7141 is formed thin, the warm-up time can be shortened. The twisted grooves 5 prevent heat conduction from the heating metal tube 1 to the reinforcing metal tube 2, helping to shorten the warm-up time. At the same time, since the reinforcing metal tube 2 reinforces the heating metal tube 1, the lobe body 6
Sufficient mechanical strength is also ensured.

In fact, when we compared and measured the warm-up time of the conventional metal roller and the fixing lobe of the above embodiment, we found that, as shown in FIG. It was found that the material becomes thicker, that is, the mechanical strength is improved, and the warm-up time is shortened.

Effects of the Invention According to the fixing roller for a copying machine of the present invention, there is an effect that m1 during warm-up can be shortened without increasing the mechanical strength of the lobe body.

[Brief explanation of drawings]

Fig. 1 is a characteristic diagram showing the relationship between the wall thickness of the metal lobe and the warm-up time, Fig. 2 is a sectional view of an embodiment of the present invention, Fig. 3 is an exploded perspective view of the lobe body, and Fig. 4 is a reinforcing metal FIG. 5, which is a sectional view of the tube, is a diagram showing the measurement results of the roller wall thickness and warm-up time of the above embodiment and the conventional example. 1... Thin-walled heated metal tube, 2... Reinforced metal tube, 3...
・Induction coil, 4...slit, 5...concave groove, 6・
... Rowo main body can 10 - Thickness - Fig. 1 Fig. 4 0 - Thickness Fig. 5 425 -

Claims (3)

[Claims] (1) A fixing roller for a copying machine, which includes a roller body in which a thin heated metal cylinder is fitted onto a reinforcing metal cylinder in which a slit is formed over the entire length in the direction of the cylinder axis, and an induction coil arranged concentrically within the roller body. . (2) The roller main body has a plurality of four heat insulating parts formed over the entire outer peripheral surface of the reinforcing metal cylinder.
Fixing roller for copying machines as described in Section 1. (3) The fixing roller for a copying machine according to claim (2), wherein the four heat-insulating parts are formed by forming grooves extending in the circumferential direction of the reinforcing metal cylinder in parallel in the axial direction of the reinforcing metal cylinder.