JPH06161313A - Heat fixing roller for copying machine - Google Patents

Abstract

PURPOSE:To shorten the heating up time, to decrease a heater capacity for heating and to uniformalize the temp. distribution over the entire width of a roller by constituting the end of the roller of a thermoplastic resin having the thermal deformation temp. of a specific value or above. CONSTITUTION:The shaft end 1b of the heat fixing roller 1 is constituted of a heat resistant polyimide resin having >=200 deg.C thermal deformation temp. The thermal deformation temp. is preferably >=230 deg.C. Such thermoplastic resin is exemplified by a polyimide resin, polyamide imide resin, polyether ketone resin, arom. polyester resin, polyphenylene sulfide resin and polybenzimidasole resin. This heat fixing roller shuts off the escape of the heat of the metallic roller heated by a heater for heating through shaft flanges then through bearings and gears. As a result, the heater capacity is decreased and the uniformity of the temp. distribution of the roller surface is greatly improved as compared with the conventional heat fixing rollers. The toner fixing with the good quality is thus executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing roller for a copying machine used in a heat fixing portion of a copying machine, and more particularly to shortening the temperature rising time, reducing the heating heater capacity, and achieving a temperature distribution of the entire width of the roller. The present invention relates to a uniform heat fixing roller for a copying machine.

[0002]

2. Description of the Related Art In a so-called copying machine (hereinafter simply referred to as a copying machine) which utilizes dry electrophotography, a toner powder image transferred from a photosensitive drum or a transfer drum onto a support such as paper is transferred onto the support. As a method of fixing to, the support is passed through a heat fixing section consisting of a heating roller and a pressure roller,
A method of fixing a toner powder image on a support by heating and pressing is used.

In this method, as the heating roller for heating and pressing the unfixed powder image, the heating roller is heated to a temperature necessary for melting the toner in a short time, and the temperature distribution is uniform over the entire width of the heating roller. It is required to be uniform. Therefore, infrared lamps with large heater capacity and resistance wire heaters have been used in the past to speed up the temperature rise, and heat insulating bushes have been used between the roller shaft end and the bearing to achieve uniform temperature. The drive gear is made of synthetic resin with excellent heat insulation.

FIG. 4 shows a conventional fixing roller for a copying machine.
The main body of the heat fixing roller 1 is made of metal such as aluminum, and the surface thereof is treated with fluororesin. Bearings 4 are provided on both shaft ends 1 a via resinous bushes 6 and are in contact with the housing 7. A heater 3 is provided at the center of the heat fixing roller 1 over the entire width. A drive gear 5 is connected to one of the shaft ends 1a, and the heat fixing roller 1 is rotated by rotating the drive gear 5.
The pressure roller 2 in contact with the pressure roller 2 is rotated. The paper (not shown) on which the toner powder image is transferred is fixed by passing between the heat fixing roller 1 and the pressure roller 2.

[0005]

However, in the conventional heat fixing roller for a copying machine as shown in FIG. 4, a large-capacity heating heater is used in order to speed up the temperature rise. As a result, the temperature of the metal roller shaft end portion rises, and the bush material is required to have heat resistance. Originally, this bush is provided as a heat insulating member because the ball bearing of the bearing cannot come into direct contact with the roller shaft end temperature rise (120 ° C or more). As a result, expensive heat-resistant resins had to be used.

For the same reason, heat-resistant resin is also used for the drive gear. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art, to provide a heat fixing roller for a copying machine capable of shortening the temperature rising time, reducing the heater capacity, and having a uniform temperature distribution over the entire width of the roller. It is what

[0007]

In the heat fixing roller for a copying machine according to the present invention, the shaft end of a metal roller having a heater inside is made of a thermoplastic resin having a heat distortion temperature of 200 ° C. or higher. It is characterized by that. The heat distortion temperature in the present invention is the heat distortion temperature measured according to ASTM-D648.

In the present invention, the thermoplastic resin forming the shaft end of the metal roller must have a heat distortion temperature of 200 ° C. or higher, preferably 230 ° C. or higher.
Examples of such a thermoplastic resin include a polyimide resin, a polyamideimide resin, a polyetherketone resin, an aromatic polyester resin, a polyphenylene sulfide resin, and a polybenzimidazole resin.

Further, as commercially available resins, "Toron" manufactured by Amoco, polyamide-imide resins such as TI resin manufactured by Toray Industries, Inc., "Vespel" manufactured by DuPont, Mitsui Toatsu Chemicals Inc.
"Aurum", TI resin from Toray Industries, Inc., Ube Industries
Polyimide resin such as "Sepra" from BASF, "Ultrapek" from BASF, "Victrex" PEEK from ICI
Polyether ketone resins such as Sumitomo Chemical Co., Ltd. "Econol", Polyplastics Co. "Vectra", Nippon Petrochemical Co., Ltd. "Zyder" and other aromatic polyester resins, Hoechst "Cerazole" Polybenzimidazole resin, polyether nitrile resin such as Idemitsu Kosan Co., Ltd. "ID300", Toray Co., Ltd. "Torelina", Dainippon Ink and Chemicals Co., Ltd. "Diecomp", Hodogaya Chemical Co., Ltd. "Sustil" Polyphenylene sulfide resin such as "" can be used.

FIG. 1 is a partial cross-sectional view of a heat fixing roller 1 showing an embodiment of the present invention, and its shaft end portion 1b is made of a heat resistant polyimide resin having a heat deformation temperature of 200 ° C. or higher. The main body of the heat fixing roller 1 is a pipe made of aluminum or stainless steel, the surface of which is treated with a fluororesin, and the shaft end 1b made of resin is screwed, adhered, heat welded or caulked. It is attached to both ends of.

In the resin shaft end 1b provided on the heat fixing roller 1, the heat of the heater 3 provided at the shaft center of the heat fixing roller 1 is transferred to the bearing 4, the drive gear 5, the housing 7 and the like. It prevents the escape and shortens the temperature rise time and the heater capacity. FIG. 2 is a partial cross-sectional view of a heat fixing roller showing another embodiment of the present invention,
The shaft end portion 1c is made of a heat-resistant resin having a heat deformation temperature of 200 ° C. or higher, which is the same as the embodiment shown in FIG. 1, but the shaft end portion 1c is fixed to the roller body by a metal radiation A heat shield plate 8 is provided. The radiant heat shield plate 8 can be provided together with the shaft end portion 1c by means such as insert molding, adhesion, and caulking. In the case of the embodiment shown in FIG. 1, the edge portion 1b ′ of the shaft end portion 1b may be carbonized depending on the capacity of the heater and the type of resin forming the shaft end portion 1b. The configuration allows for prevention.

[0012]

EXAMPLES The present invention will be described below with reference to examples. Examples 1, 2 and Comparative Example 1 A 60 mmφ fluororesin-coated aluminum heat fixing roller was removed, and the roller shaft end portion was modified to a polyamideimide resin shaft end portion having the structure shown in FIGS. 1 and 2. , P
It was reattached to the PC copying machine (Examples 1 and 2). Then, a steady operation was performed for 3 hours at a heater capacity of 900 W / 350 W while comparing with that before modification (Comparative Example-1).

Positions A, B, C, D, E, F, shown in FIG.
The temperature conditions measured by F ′, G and H are shown in Table 1
1, 2 and the values shown in Comparative Example-1, which are superior in uniformity of the surface temperature of the roller as compared with Comparative Example-1 before the improvement of the heat fixing roller, and required for raising the temperature to a predetermined temperature. The time is reduced by 21 to 36 seconds (improvement effect 11 to 18
%) Furthermore, the power consumption was reduced by 10 to 15%.

Further, since the temperature of the gear mounting portion is lowered from 120 ° C. to about 60, this gear has an economic effect that can be used even for a commonly used plastic gear.
Further, it is not necessary to use the heat insulating bush, or even if it is used, it is economical because it is a general-purpose plastic and has a good temperature level. Example-3 The same experiment as in Example-2 was performed, but this time, the heater capacity was 720 W / 350 W and the heating heater capacity at the time of temperature increase was 80% of 900 W. The test status at this time is shown in Table-1.
The heat-up time is as shown in Fig.
1) It was almost the same, but the power consumption could be reduced by about 15%, and the uniformity of the roller surface temperature was also good.

[0015]

[Table 1]

[0016]

The heat fixing roller of the present invention blocks the heat of the metal roller heated by the heater from escaping through the bearings and gears through the shaft flange, thereby lowering the heater capacity. Uniformity of temperature distribution on the surface is greatly improved compared to the conventional product, and high quality toner fixing can be performed. Furthermore, since it is not preferable to directly use a ball bearing because the temperature of the shaft flange has risen above 120 ° C, a heat insulating bush is used between the shaft and the bearing, and this heat insulating bush blocks the temperature of the shaft. I was able to use ball bearings. This heat insulating bush is 120 ° C or higher, preferably 150
General-purpose plastics cannot be used due to lack of heat resistance because they require heat insulation of ℃ or more, and heat insulation bushes made of expensive heat-resistant resin were used, but this heat insulation bushing is used by adopting the present invention. You don't have to Further, the gear material can be changed to a cheaper material.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a heat fixing roller according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a heat fixing roller that is another embodiment of the present invention.

FIG. 3 is a diagram showing a temperature measurement position of a heat fixing roller measured in an example.

FIG. 4 is a cross-sectional view showing a conventional heat fixing roller.

[Explanation of symbols]

1 Heat Fixing Roller 1a, 1b, 1C Shaft End 2 Pressure Roller 3 Heating Heater 4 Bearing 5 Drive Gear 6 Bushing 7 Housing 8 Radiant Heat Shielding Plate

Claims (3)

[Claims] 1. A heat fixing roller for a copying machine, characterized in that a shaft end of a metal roller having a heater inside is made of a thermoplastic resin having a heat distortion temperature of 200 ° C. or higher. 2. The thermoplastic resin is at least one resin selected from a polyimide resin, a polyamideimide resin, a polyetherketone resin, an aromatic polyester resin, a polyphenylene sulfide resin and a polybenzimidazole resin. Heat fixing roller for copiers. 3. The heat fixing roller for a copying machine according to claim 1, wherein a radiant heat shield plate is provided on the roller body side of the shaft end portion made of a thermoplastic resin.