JPH0413711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat roller type fixing device for a copying machine.

(Prior Art) As shown in FIG. 1, a conventional heat roller type fixing device includes a heat roller 3 and a heat roller 3 rotatably mounted between two support frames 1 and 1' using bearings 2 and 2'. , and a pressure roller 4 provided in pair with the roller 3, and as shown in FIG. A light image of the original document 9 placed on the platen glass 8 is exposed to the surface of the photoreceptor 5 by an optical device, and the image is developed by the developing device 10. Then, in the transfer section 6 of the photoreceptor 5, The copy paper is transferred onto the copy paper fed from the paper feed section 11 and is waited for to be conveyed by the transport 12, and the copy paper passes between the heat roller 3 and the pressure roller 4. The image is fixed by applying a predetermined amount of heat energy and pressure when fixing the image. As shown in FIG. 3, the heat roller 3 used in the fixing device usually has both ends of the heater 13 disposed inside the heat roller 3, as shown in FIG.
By fixing to the outside of the support frames 1, 1' using substantially L-shaped support members 14, 14',
Since the foil portion 15 placed inside the heat roller 3 is inserted into the heat roller 3, the heater 13
The temperature rise in this part is high due to the direct heat generated by the foil part 15, which accelerates the oxidation of the foil part 15 and shortens the life of the heater 13 itself. The lead wire 16 connected to the wire must be made of a material with extremely high heat resistance, which has the disadvantage that the wire 16 itself is expensive.
As shown in FIG. 4, support frames 1,
If a heat insulating cap or shielding plate 17 is arranged outside the heater 1' and the vicinity of the contact point of the foil portion 15 and the lead wire 16 is housed in the heat insulating cap or the like 17, the temperature at both ends of the heater 13 will rise. becomes even hotter, and as a result, the oxidation of the foil portion 15 further increases, which not only shortens the life of the heater 13, but also requires the lead wire 16 to be made of a more expensive wire with better heat resistance. It had some drawbacks when I had to use it.

(Object of the Invention) The present invention has been made in order to eliminate the drawbacks of the conventional fixing device described above. In addition to extending the life of the heater itself, the reliability of the device itself is improved by allowing the use of cheaper lead wires with lower heat resistance than conventional wires of this type. The object of the present invention is to provide a fixing device for a copying machine.

(Structure of the Invention) For this purpose, the length of the heater disposed inside the heat roller is appropriately longer than the length in the axial direction of the heat roller, and thereby the foil portions at both ends of the heater are A heat insulating cap or shielding plate 17 or the like is provided on the outside of both ends of the heat roller 3 so as to protrude outward from the heat roller 3, and the foil part 15 of the heater disposed inside the heat roller 3 is connected to the heat insulating cap or shielding plate. The foil portion is located outside of the plate 17, etc., to reduce the degree of oxidation of the foil portion and extend its life.
Furthermore, the lead wires are also highly heat resistant, so there is no need to use them.

(Example) The present invention will be described in detail below based on an example shown in the drawings.

Incidentally, FIG. 5 shows an embodiment of the fixing device of the present invention, in which a heat insulating cap or shielding plate 17 is provided on the outside of the support frames 1, 1' to prevent the heat generated from the heater 13 from escaping to the outside of the device. , both ends of the heater 13 are further extended outward to protrude outside a through hole 18 formed in a heat insulating cap or shielding plate 17, and both ends are fixed with a support member 14. Foil portions 15 inside both ends of the heater 13
In addition, the contact point of the lead wire 16 and its vicinity are located outside the heat insulating cap or shielding plate 17 to minimize the temperature rise due to heat generated by the heater 13.

(Effects of the Invention) When heat insulating caps or shielding plates 17 are placed on both outsides of the support frames 1 and 1' to prevent the heat generated by the heater 13 from leaking outside the device, both ends of the heater 13 can be heated. A simple configuration in which the roller 3 is extended from both ends to protrude outward from the heat insulating cap or shielding plate 17 can minimize the temperature rise in the foil portion 15 due to the heat generated by the heater 13. This makes it possible to reduce the degree of oxidation of the foil portion 15, thereby extending the life of the heater 13 itself, and also requires the lead wires 16 connected to both ends of the heater to have a high degree of heat resistance. This has the advantage that it is not necessary to do so, and therefore costs can be reduced.

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional front view of a conventional heat roller type fixing device, Figure 2 is a schematic layout of the main parts of a copying machine using the fixing device, and Figure 3 is a partial cross-sectional front view of a conventional heat roller type fixing device. FIG. 4 is a cross-sectional front view showing one embodiment of the mounting state of the arranged heater, FIG. 4 is a cross-sectional front view showing another example of the installed heater, and FIG. In the figure, 1, 1'...support frame, 2, 2'...bearing, 3...heat roller, 4...pressure roller, 5...photoreceptor, 6...transfer section, 7... Output tray, 8... Platen glass, 9... Document, 1
1...Paper feed section, 12...Transport, 13...
...Heater, 14, 14'...Support member, 15...
... Foil part, 16 ... Lead wire, 17 ... Heat insulation cap or shielding plate, etc., 18 ... Through hole.

Claims (1)

[Claims] 1. When copy paper with an unfixed toner image transferred passes through the contact area between a heat roller and a pressure roller that are rotatably installed between two support frames, a predetermined amount of thermal energy and pressure is applied to the paper. In a heat roller type fixing device configured to perform image fixing in addition to the above, heat insulating caps or shielding plates are provided outside both ends of the heat roller, and a heater foil is disposed inside the heat roller. 1. A fixing device for a copying machine or the like, characterized in that a fixing device for a copying machine or the like is located outside the heat insulating cap or the shielding plate.