JPH01979A - heat fixing roller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a heat fixing roller that fixes an unfixed powder image to a recording paper by generating heat from a resistor attached to the surface of a roll-shaped substrate.

The purpose is to improve the thermal responsiveness of the interrupting member that interrupts the wiring that connects the power source to the resistor.

This cutoff member is inserted between electrodes provided at both ends of a resistor for connecting a power source to the resistor and between electrodes on the side where the resistor is interposed.

[Industrial application field]

The present invention relates to a heat fixing roller that fixes an unfixed powder image to a recording paper by heat generated by a resistor mounted on the surface of a roll-shaped substrate.

[Conventional technology]

FIG. 4 is a diagram showing a schematic configuration of a conventional heat fixing roller, with FIG. 4(a) showing the overall configuration and FIG. 4(kl) showing a partial view.

In the figure, ■ is a roll-shaped substrate, and 2 is an insulating layer.

3a and 3b are electrodes, 4 is a resistor layer made of alumina ceramic, 5 is an insulating layer, and 6 is a surface layer, which is a Teflon coating layer. Configure.

Furthermore, 7 is a power supply, and a power supply member (brush) ll that slides on electrodes 3a and 3b provided at both ends of the resistor 4, respectively.
a, one that applies voltage to the resistor 4 via llb, 8
is a temperature fuse that detects the temperature near the first surface layer 6 and connects the electrodes 3a, 3b, power source 7. The closed loop wiring 9 made up of the resistor 4 is cut off to prevent the heat roll 10 from rising in temperature excessively.

As described above, in the heat fixing rollers used in electrophotographic copying machines, electrophotographic printers, etc., excessive temperature rise due to temperature control abnormalities can immediately lead to fire failure, so two types of external devices are connected to fuses (thermostats, etc.). It is set up.

[Problem that the invention seeks to solve]

However, in the heat fixing roller configured as described above, the ambient temperature of the fuse 8 is lower than the temperature of the surface N6, and the fuse itself has a large heat capacity. In many cases, the device would not operate unless the temperature exceeded the failure temperature of the 10 itself or surrounding structures. That is, as shown in Fig. 3, the fuse part temperature (curve C) is lower than the heat roll temperature (curve Δ).
turn into.

Therefore, in an abnormal state where the fuse is activated, there is a problem in that not only the heat roller 10 but also the entire fixing unit and throat must be replaced.

In addition, if the heat roller has a small diameter of 10 ga, fuse 8
The problem was that it was difficult to install.

The object of the present invention is to solve the above-mentioned conventional problems.

An object of the present invention is to provide a heat fixing roller capable of improving the thermal response of a temperature fuse.

[Means for solving problems]

FIG. 1 is a diagram illustrating the principle of a heat fixing roller according to the present invention.

In the figure, the same parts as in FIG. 4 are given the same numbers, and their explanations are omitted. The difference from FIG. This is because the wiring 9 is provided so as to be cut off.

[Effect]

Therefore, it is formed integrally with the resistor 4.

It becomes possible to make the ambient temperature of the temperature fuse 8 and the temperature of the surface layer 6 substantially the same, and it becomes possible to improve thermal response.

〔Example〕

FIG. 2 is an explanatory view of an embodiment of the heat fixing roller according to the present invention, and is an enlarged view of the electrode portion. Moreover, FIG. 3 is a comparison diagram of thermal responsiveness.

In the figure, the difference from the one shown in FIG. 4 is that the rolled base 1. A step is provided in the insulating layer 2.

Glass wool 21 is embedded in this stepped portion 20.

Solder r on the top to connect the electrode 3a and the resistor 4.
The point is that f422 is installed at multiple locations in the circumferential direction.

Therefore, as shown in Fig. 3, the fuse part temperature (curve B
) can be made to approximately match the heat roll temperature (curve A). With the configuration described above, when the temperature of the heat roll 10# rises abnormally, the solder layer 22 is melted and missing, and the glass wool 21 is impregnated with the electrode 3a.
and the resistor 4 can be cut off.

In order to prevent short circuits, glass wool impregnated with solder is used, but for example, insulating dam plates may be provided at a plurality of locations at the five step portions to prevent flow in the circumferential direction.

Further, although the solder layer is provided near the electrode portion, it may be provided at an intermediate position in the axial direction so as to isolate the resistors 4 from each other.

Also, a solder layer was used as a temperature fuse.

A bimetal, a shape memory alloy, or the like may be used to perform the thermal fuse function. Therefore, according to the two embodiments,
It is possible to loosen the temperature fuse function by 1eJ before the temperature of the heat roll reaches the failure temperature, so there is no problem of damaging the unit, and there is no problem of damaging the surface layer like with conventional contact type fuses. It will not wear out.

〔Effect of the invention〕

As explained above, one aspect of the present invention is a power source.

Since the interrupting member that interrupts the closed loop wiring composed of the electrode and the resistor is provided between the electrodes where the resistor is interposed, the thermal response can be improved.

Therefore, even if the heat roll becomes abnormally heated.

It becomes possible to stop power supply without damaging other units.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is an explanatory diagram of an embodiment, FIG. 3 is a comparison diagram of thermal response, and FIG. 4 is a schematic diagram of a conventional heat fixing roller. In the figure, 3a and 3b are electrodes, and 4 is a resistor. 6 is a surface layer, 7 is a power supply, 8 is a temperature fuse, 9 is a closed loop wiring, 20 is a stepped portion, and 22 is a solder layer. Kiyoshi, explanation diagram No. 2 Σ explanatory diagram of the laughing side 2nd t (FJ! Seki) C6l) When the standing date is gone Comparison diagram 3rd scene

Claims (1)

[Claims] A rolled base (1), a resistor (4) attached to the surface of the rolled base (1), a surface layer (6) provided to cover the resistor (4), and the resistor. electrodes (3a, 3b) provided at both ends of the body (4) for connecting the power source (7) to the resistor (4); and the electrodes (3a, 3b).
, a power source (7), and a resistor (4), and a shutoff member (8) for disconnecting the closed loop wiring (9) when the temperature near the surface layer (6) reaches a predetermined temperature or higher. , wherein the blocking member (8) is inserted between the electrodes (3a, 3b) with the resistor (4) interposed therebetween.