JPH0744048A - Driving gear for thermal fixing roller for copying machine - Google Patents

Abstract

PURPOSE:To obtain excellent durability without receiving the radiation heat of a heater and without carbonization and deterioration of the driving gear of the thermal fixing roller by providing the surface in the key part of the gear with a heat shielding object. CONSTITUTION:A slit 8a having a T-shaped section is formed in the key part 8 of the driving gear 5 and one surface of the shielding plate 9 made of aluminum is provided with a projection 9a having a shape corresponding to the slit 8a. The inner peripheral surface of the driving gear 5 is eventually provided with the shielding plate 9 made of metal by sliding and fitting this projecting 9a into the slit 8a. The radiation heat emitted from the heater in the thermal fixing roller is shielded by this shielding plate 9. The thermal deformation temp. of a thermoplastic resin used for the driving gear 5 is >=200 deg.C, more preferably >=230 deg.C. Such thermoplastic resin is exemplified by a polyimide resin, polyether imide resin, polyamide imide resin, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive gear for a heat fixing roller for a copying machine, and more particularly to a drive gear for preventing deterioration of a heater in the roller due to heat.

[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 copying 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. 2 shows a fixing roller portion of a conventional copying machine. The main body of the heat fixing roller 1 is made of metal such as aluminum and the surface thereof is processed with a 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. Further, a drive gear 5 made of resin is connected to one shaft end portion 1a, and by rotating the drive gear 5, the pressure roller 2 in contact with the heat fixing roller 1 is rotated. Has become. Paper with toner powder image transferred
(Not shown) is fixed by passing between the heat fixing roller 1 and the pressure roller 2.

FIG. 3 is an assembled perspective view showing a state where the shaft end 1a of the heat fixing roller 1 and the drive gear 5 are connected to each other. The inner peripheral surface of the drive gear 5 has a protruding key portion 8 extending in the gear width direction.
Is integrally provided, and the drive gear 5 and the heat fixing roller 1 are connected by fitting the key portion 8 into the notch 1b of the heat fixing roller shaft end portion 1a.

[0006]

However, in the conventional heat fixing roller for a copying machine shown in FIGS. 2 and 3, in order to raise the temperature of the roller rapidly and evenly in the length direction, it is necessary to adjust the length of the roller rather than the length of the roller. Since the heater with a long and large capacity is built in, the heat of the heater is transmitted to the driving gear made of resin, and there is a problem that the gear deteriorates or is carbonized.

Particularly, since the key portion of the drive gear is exposed to the inside of the heat fixing roller, carbonization of this portion is severe,
There was rattling in the fitting, which hindered power transmission, and eventually resulted in gear damage. In order to eliminate such inconvenience, the material of the gear is changed to heat resistant resin,
It has been attempted to divide the heater into two stages and install a heater with a small wattage near the gear, or to increase the length of the roller shaft end portion 1a to keep the heater away from the gear, but in both cases, it is It was ineffective and economically inconvenient.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a heat fixing roller having a heater having a rapid temperature rise and a uniform temperature distribution over the entire width of the roller. Another object of the present invention is to provide a driving gear for a heat fixing roller for a copying machine, which can be used for a long period of time, and in particular, prevent deterioration and carbonization of a key portion.

[0009]

A drive gear of a heat fixing roller for a copying machine according to the present invention is a drive gear of a metal heat fixing roller for a copying machine having a heater therein, and a shaft end of the roller. To have a protruding key portion that fits into the notch, integrally mold the gear with this key portion with a thermoplastic resin having a heat deformation temperature of 200 ° C. or more, and provide a heat shield on the surface of the key portion. It is characterized by.

The heat distortion temperature in the present invention is ASTM-
The thermoplastic resin used for the driving gear of the present invention has a heat distortion temperature of 200 ° C or higher, preferably 230 ° C or higher. Examples of such thermoplastic resin include polyimide resin, polyetherimide resin, polyamideimide resin, polyetherketone resin,
Aromatic polyester resins, polyphenylene sulfide resins, and polybenzimidazole resins can be mentioned.

Further, as commercially available resins, "Tolon" manufactured by Amoco, polyamide-imide resins such as TI resin manufactured by Toray Co., Ltd., "Vespel" manufactured by DuPont, and Mitsui Toatsu Chemical Co., Ltd.
"Aurum", TI resin from Toray Industries, Inc., Ube Industries
Polyimide resin such as "Sepra" from BASF Corporation
"Ultrapek", ICI's "Victorex" PEEK
Polyetherketone resins such as Sumitomo Chemical Co., "Econol", Polyplastics Co. "Vectra", Nippon Petrochemical Co., Ltd. "Zider" and other aromatic polyester resins, Hoechst "Cerazole". Polybenzimidazole resin, polyether nitrile resin such as Idemitsu Kosan Co., Ltd. "ID300", Toray Co., Ltd. "Torelina"
Polyphenylene sulfide resins such as "Daicomp" manufactured by Dainippon Ink and Chemicals, Inc., "Sasteel" manufactured by Hodogaya Chemical Co., Ltd., and polyetherimide resins manufactured by GE can be used.

In the present invention, the heat shield provided on the surface of the key of the drive gear is not particularly limited as long as it can shield or reduce the heat from the heater, and is, for example, a metal plate or a heat resistant paint. Means for providing a heat shield on the surface of the key include mechanical fixing such as fitting, press fitting, caulking, and bolting, chemical fixing such as adhesion and welding, or coating.

FIG. 1 shows an example in which a heat shield is provided on a drive gear according to the present invention. FIG. 1 shows an embodiment of the drive gear of the present invention, in which the key portion 8 of the drive gear 5 has a cross section T.
A character-shaped slit 8a is formed, and a projection 9a having a shape corresponding to the slit 8a is formed on one surface of the aluminum shield plate 9.
Is provided. Then, the protrusion 9a is formed into the slit 8a.
By slidingly fitting into the drive gear 5, a metallic shield plate 9 is provided on the inner peripheral surface of the drive gear 5, and the radiant heat emitted from the heater in the heat fixing roller is blocked by the shield plate 9.

[0014]

EXAMPLES The present invention will be specifically described with reference to the following examples. Example 1 and Comparative Example 1 A PPC copier in which a drive gear (see FIG. 3) made of polyphenylene sulfide resin containing 40% of glass fiber was attached to a notch at the end of the shaft of a heat-fixing roller made of 40φ fluororesin-coated aluminum. After operating under normal use conditions,
The key portion melted and carbonized black after 240 hours of operation (Comparative Example 1).

On the other hand, a key gear of a drive gear made of the same material is formed with a slit shown in FIG. 1, and a slit 9a is formed on an aluminum plate (thickness 0.3t) having a projection 9a on one side thereof. When a drive gear having the plate 9 inserted and fitted therein was used and similarly operated for 240 hours, no carbonization deterioration of the key portion was observed. Example 2 In the combination of the drive gear and the roller in Example 1, a 0.3 t aluminum plate was adhered to the key part surface of the gear using a polyimide resin adhesive having a heat resistant temperature of 300 ° C., and the radiant heat of the heater was applied to the key part. It was prevented from reaching. Using this, the same experiment as in Example 1 was performed, but no carbonization deterioration of the key part was observed. Example 3 In the combination of the drive gear and the roller in Example 1, the NMP solution of polyimide resin containing 30% of stainless powder was applied to the surface of the gear key portion and dried at 250 ° C. to form a polyimide resin film containing stainless powder. It was
When this was used to perform the same experiment as in Example 1, no carbonization of the key portion was observed.

[0016]

The drive gear of the heat fixing roller for a copying machine of the present invention is provided with a heat shield on the surface of its key portion, so that it does not receive the radiant heat of the heater and the gear does not deteriorate due to carbonization. Shows durability.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a drive gear according to the present invention.

FIG. 2 is a sectional view of a heat fixing roller portion of a conventional copying machine.

FIG. 3 is an assembled perspective view of a conventional drive gear.

[Explanation of symbols]

1 Heat Fixing Roller 1a Shaft End 2 Pressure Roller 3 Heater 4 Bearing 5 Drive Gear 6 Bush 7 Housing 8 Key 8a Slit 9 Shield 9a Projection

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[Procedure amendment]

[Submission date] August 18, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

The driving gear of the heat fixing roller for a copying machine according to the present invention is a metal having a heater inside.
A drive gear manufacturing copiers heat fixing roller having a protruding key portion fitted in-out shaft end notch of said roller, the gear and heat distortion temperature of 200 ° C. or more with the key portion It is characterized in that it is integrally molded with a thermoplastic resin and a heat shield is provided on the surface of the key portion.

Claims (3)

[Claims] 1. A driving gear of a metallic heat fixing roller for a copying machine, which has a heater inside, and has a protruding key portion that fits into a notch of the shaft end of the roller. A drive gear for a heat fixing roller for a copying machine, characterized in that the gear is integrally molded with a portion of a thermoplastic resin having a heat deformation temperature of 200 ° C. or more, and a heat shield is provided on a surface of a key portion. 2. The thermoplastic resin is at least one resin selected from a polyimide resin, a polyetherimide resin, a polyamideimide resin, a polyetherketone resin, an aromatic polyester resin, a polyphenylene sulfide resin and a benzimidazole resin. Item 1. A drive gear for a heat fixing roller for a copying machine according to Item 1. 3. A drive gear for a heat fixing roller for a copying machine, wherein the heat shield is a metal plate.