JPS63167390A - Thermal fixing roll for copying machine - Google Patents

Abstract

PURPOSE:To prevent a sheet of paper from being inserted into a gap between a slip ring and a collector ring by providing the slip ring with end parts thicker than an adhesion preventing layer and statically engaging the end parts with the slip ring. CONSTITUTION:The slip ring 15 is formed like a regular circle, a recessed part 15a abutted upon the collector ring 17 is formed on the center part of the outer peripheral surface of the slip ring 15, the thickness T of both the end parts 15b, 15c of the slip ring 15 is formed so as to be thicker than that of the adhesion preventing layer 16, and the end face 15d of the end part 15b is projected from the layer 16. When power is supplied from the collector ring 17 to the slip ring 15, a heat generating resistor layer 13 is heated and an image is thermally fixed to paper S on the thermal fixing roll H. If the paper S is rotated while being shifted, the paper S is moved to the slip ring side and its end part S1 collides with the end face 15d of the slip ring 15. While being regulated at its advancing direction by the end face 15d, the paper S is raised in an arrow A21 direction. Since the paper can be prevented from being entered into the gap between the slip ring 15 and the collector ring 17, generation of fire can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a heat fixing roll used in a copying machine, and more specifically to a heat fixing roll for an electronic copying machine.

2. Description of the Related Art An electronic copying machine is provided with a heat fixing roll for heating and fixing a dry developer mainly composed of colored toner and resin onto a support.

As shown in FIGS. 2 and 3, the conventional heat fixing roll has an insulating layer 2 formed on the surface of a metal tube 1, and strip-shaped heating resistor layers 3 and grooves 4 alternately formed on the surface in a threaded manner. A slip ring 5 is formed on the end of the resistor layer 3 at approximately the same level, and an adhesion prevention layer 6 is formed on the remaining part, and a current collector 7 is applied to the slip ring 5. Electricity is supplied to the resistor layer 3 by contacting the resistor layer 3.

Note that 8.9 indicates the bearing, and arrow A3 indicates the direction of current flow.

Problems to be Solved by the Invention In the conventional heat fixing roller, the surface of the slip ring 5 and the surface on the anti-adhesive layer 6 are located on the same level, so the paper P on the anti-adhesive layer 6 is misaligned. If it moves in the direction of arrow A6, it may enter between the slip ring 5 and the current collector 7. If the paper enters in this way, a spark discharge will occur between the slip ring 5 and the current collector 7, and the paper will ignite, potentially causing a fire.

Moreover, since the slip ring 5 is formed by thermal spraying,
Its surface is uneven and its roundness is poor.

Therefore, the slip ring 5 is not in complete surface contact with the current collector 7, which adversely affects power supply. Furthermore, if the slip ring 5 is formed after the adhesion prevention layer 6 is formed, the prevention layer 6 will be heated to a high temperature during thermal spraying and will be damaged.

Therefore, the slip ring 5 is formed before forming the adhesion prevention layer 6, but if this is done, the slip ring 5 is heated and oxidized when the adhesion prevention layer 6 is formed.

This oxidation is not limited to the surface, but also penetrates into the pores created by thermal spraying and oxidizes the inside.

As a result, resistance increases, causing trouble in power supply.

This invention aims to prevent paper from getting between the slip ring and the current collector in consideration of the above-mentioned circumstances.

Another purpose is to improve the roundness of the slip ring and to prevent it from oxidizing.

Means for Solving the Problems This invention forms a heating resistor layer on the surface of a cylindrical insulating support, and a slip ring is attached to the end of the resistor layer.
Further, in a heat fixing roll for a copying machine having an adhesion prevention layer formed on the remaining portion thereof, the slip ring has an end portion that is thicker than the adhesion prevention layer and is statically fitted. This is a heat fixing roll for machines.

Function: In advance, a slip ring with thicker end portions from the adhesion prevention layer side is machined into a perfect circle, and then this slip ring is statically fitted to the heating resistor layer, and the end portions are attached to the adhesion prevention layer. Connect.

If the paper on the adhesion prevention layer shifts and moves toward the slip ring, the paper will never come between the current collector and the slip ring because its direction of movement is restricted by the end of the slip ring.

Embodiment An embodiment of the present invention will be described with reference to FIG.
2, and a band-shaped heating resistance layer 13 and grooves 14 are formed on the surface thereof.
and are alternately formed into a screw shape.

The surface of this heating resistor layer 13 is coated with fluorocarbon resin or silicone resin to form an adhesion prevention layer 16.

The slip ring 15 is formed into a perfect circle by machining, and a recess 15a that contacts the current collector 17 is formed in the center of its outer peripheral surface.

Further, the thickness T of both ends 15b and 15c of the slip ring 15 is formed to be thicker than the thickness of the adhesion prevention layer 16.
An end surface 15d of the adhesive layer 5b protrudes from the adhesion prevention layer 16.

Next, the operation of this embodiment will be explained.

When power is supplied from the current collector 17 to the slip ring 15, the heating resistor layer 13 is heated, and thermal fixing is performed on the paper S on the thermal fixing roll-H.

At this time, when the paper S rotates while being shifted, the paper S moves toward the arrow A.
As shown by 20, it moves toward the slip ring 15, and its end S1 collides with the end surface 15d of the slip ring 15.

Then, the end face 15d moves upward in the direction of arrow A21 while the direction of movement is restricted.

The present invention is not limited to the above-mentioned embodiments. For example, instead of forming strip-shaped heating resistor layers and grooves alternately in a screw shape on the surface of a cylindrical insulating support, the surface of the cylindrical insulating support is It may be covered with a heating resistor layer.

In this invention, as described above, the slip ring has an end portion that is thicker than the adhesion prevention layer side, so that when the paper on the adhesion prevention layer shifts and moves toward the slip ring side, the paper is Its direction of movement is regulated.

Therefore, paper does not get caught between the slip ring and the current collector, so it is possible to prevent a fire from occurring. Further, since the slip ring is statically fitted, if the slip ring is previously formed into a perfect circle by machining, a slip ring with good roundness can be obtained.

Furthermore, if the slip ring is statically fitted after forming the adhesion prevention layer, it will not be heated during the formation of the adhesion prevention layer, and therefore will not be oxidized.

Therefore, since the resistance value does not increase, stable power supply can be performed.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the present invention. FIG.
FIG. 3, a plan view showing a conventional example, is an enlarged sectional view taken along the line 1-11I in FIG. 2. 12... Insulating layer 13... Heat generating resistor layer 15... Slip ring 15b... End part

Claims (3)

[Claims] (1) For copying machines in which a heating resistor layer is formed on the surface of a cylindrical insulating support, a slip ring is formed at the end of the resistor layer, and an adhesion prevention layer is formed on the remaining part. A heat fixing roll for a copying machine, characterized in that the slip ring has an end portion thicker than the adhesion prevention layer and is statically fitted. (2) A heat fixing roll for a copying machine according to claim 1, wherein the heating resistor layer is strip-shaped. (3) The heat fixing roll for a copying machine according to claim 1, wherein the slip ring has a recess formed in the center of its outer peripheral surface.