JPS59111178A - Heat roller for fixing - Google Patents

Abstract

PURPOSE:To suppress a temperature drop on the surface of a roller by interposing >=1 heat insulating layers which are superior in heat insulation to the elastic or nonelastic layer of the roller on an unheated side in the elastic or nonelastic layer in the circumferential direction of the roller. CONSTITUTION:A lower 12 which is pressed against an upper roller 11 which has a heater faces the reverse surface of a form 8 and is constituted by covering a cylindrical mandrel 15 of A1, etc., with the elastic layer 16. Then, at least one heat insulating layer is interposed circumferentially in the layer 16 of the lower roll 12 to prevent the elasticity of the layer 16 from being spoiled. The layer 17 is superior in heat insulation to the layer 16. Thus, the heat insulating layer 17 is interposed in the layer 16 of the lower roller 12 in the circumferential direction of the roller 12 to suppress a temperature drop on the roller surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a fixing heat roller used as a heat fixing means in a copying machine or the like.

<Prior Art> In copying machines, etc., in order to thermally fix the toner image formed on paper, the paper is passed between mutually pressurized rollers, and the toner is fixed by the heat of the rollers. Heat rollers are widely used. As an example of this heat roller is shown in FIG. 1, rollers 1 and 2 that are pressed together are heated and controlled to a temperature at which toner can be fixed. The roller 1 is formed by covering the surface of a core metal 3 made of a metal such as Al (Al < aluminum) with good thermal conductivity with a layer 4 made of Teflon PFA or PTFE or the like having release properties such as toner. The lower roller 2 that comes into pressure contact with the roller 1 is constructed by covering the surface of a core metal 5 made of metal such as A1 with a layer 6 made of silicone rubber (HTV or RTV), etc., which has more elasticity than the layer 4. 21 and 2 constitute a heat roller.

In addition, the heat roller shown in Fig. 2 has upper and lower rollers 1 and 2.
In both cases, an example is shown in which the outer layer is an elastic layer of silicone rubber or the like with a thickness of 6°6. In this way, the heat roller for fixing improves paper conveyance,
Furthermore, in order to ensure the fixability of the toner image after development,
It is necessary to provide an elastic layer 6 on at least one of the upper and lower rollers 1 and 2. This is to obtain appropriate contact 1] and knob width by the upper and lower rollers 1 and 2. That is, the paper speed during contact between the lower rollers 1 and 2.

This is done to ensure the minimum level of safety under conditions such as the amount of heat supplied, the heat capacity of the rollers, and the surface temperature of the rollers.

However, the layer 6 on the core metal 5 for forming the heat roller has elasticity, and in order to make the heat roller have an elasticity of 8 mm, the layer 6 etc. on the core metal 5 for forming the heat roller must have a certain thickness of 4 to 8 mm.
This is the most common example of heat capacity.This is the cause of the increase in heat capacity. This is because when a plurality of copies are being made, heat is transferred from the tenth roller 1 to the paper, and at the same time, heat is also transferred to the lower roller 2. At this time, the upper and lower rollers are idly rotating between one sheet of paper and the next sheet of paper, and the heat transfer to the lower roller is the largest. Therefore, upper roller 1
This has the drawback of causing a decrease in surface temperature and causing poor fixing.

<Object of the Invention> In view of the shortcomings of conventional heat rollers, the present invention aims to prevent heat transfer and suppress a decrease in temperature of the roller surface on the side that comes into contact with toner.

<Embodiment> The present invention provides a heat roller having the structure shown in FIG. 3 in order to prevent heat transfer between the upper and lower rollers of the heat roller. As shown in the figure, the heat rollers are upper and lower rollers I+ and +2.
It is composed of. The soil roller 11 is a roller that comes into contact with the toner 9 on the paper 8, and is constructed by covering a cylindrical core metal 13 made of AI or the like with a layer 14 having good mold releasability. Although not shown in the figure, this roller 11 is provided with a heater inside the core metal 13.1. The surface of O-211 is heated to a set temperature (temperature that allows fixing). The lower roller 12, which is pressed against the upper roller 11, faces the back side of the paper 8, and is made of a cylindrical core metal 15 made of AI or the like and coated with an elastic layer 16. Within the layer 16 of the lower roller 12, there is a layer 1
At least one heat insulating layer of 7 is interposed in the circumferential direction,
This is done so as not to damage the elasticity of the layer 16. Above layer) 7
is thicker than the heat insulating properties of the layer 16.

As mentioned above, since the heat insulating layer 17 is interposed in the circumferential direction of the roller 12 within the layer 16 of the lower roller 12, it is clear that it has the effect of blocking heat transfer from the soil roller 11 to the lower roller 12. It is. Here, the insulation layer 17 outer layer of soil l
If the layer 6-2 is thicker, the heat transfer from the upper roller I+ will be less than that of FIG. 1, but a significant amount of heat transfer will still occur.

To do this, the outer layer 16-2 of the layer 16 must be replaced with the inner layer +6-1
If it is made as thin as possible compared to , the effect of suppressing heat transfer will increase. Although the example shown in FIG. 3 shows an example in which only one layer of the heat insulating layer 17 is interposed within the layer 16, the present invention is not limited to this.
A multilayer structure may be used in which the heat insulating layers 17 are alternately laminated to form the outer surface of the layers 16.

Furthermore, although an example has been described in which the heat insulating layer 17 is interposed within the elastic layer 16, it is clear that the present invention can also be practiced in a case where the heat roller is made of a non-elastic member. In other words, in the roller that comes into contact with the heated roller, a heat insulating layer may be interposed in the layer made of the inelastic material of the roller.
The heat insulating layer 17 is preferably made of asbestos or glass fiber. The lower roller 12 has a layer 16-1 made of an elastic member such as 7-recon rubber on a cylindrical core 15, and a layer 17 formed by covering the layer 16-1 with a heat insulating material such as asbestos. Further, a thin layer 16-2 is formed thereon using the same material as the layer 16-1.

The lower roller 12 is manufactured by simultaneously vulcanizing and polishing the outer shape.

<Effects of the Invention> The present invention provides a heat roller for fixing, in which a heat insulating layer having a heat insulating property exceeding that of the 9+11 or inelastic layer of the other roller is provided in order to prevent heat transfer from one roller part. Since one or more layers are interposed in the circumferential direction of the roller, heat transfer from one roller to the other roller can be suppressed, and a drop in temperature on the roller surface can be prevented.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the internal structure of a conventional heat roller, and FIG. 3 is a cross-sectional view showing the internal structure of a heat roller according to the present invention. 11: Upper roller 12: Lower roller 13. +4: Core metal 15: Layer with mold releasability 16: Elastic layer 17: Heat insulating layer Figure 1 2nd So 1 31 ¥1

Claims (1)

[Claims] 1. In a fixing heat roller that is provided with a pair of rollers consisting of a core made of a rigid material such as metal and a layer coated with an elastic or inelastic material on the surface of the core, one of the rollers is heated. A heat roller for fixing, characterized in that one or more heat insulating layers having a heat insulating property higher than that of the layer of the other roller are interposed in the circumferential direction of the roller in order to prevent heat transfer from the heat roller to the other roller. .