JPH07192845A - Heat roller - Google Patents

Abstract

(57) [Summary] [Structure] In a heat roller in which a heating resistor layer 15 and a fluororesin surface coating layer 17 are provided on an outer peripheral surface of a metallic cylindrical substrate 11 with an electric insulating layer 13 interposed therebetween, the electric insulating layer is boron. It is formed from an organometallic polymer such as a siloxane polymer. [Effects] The electrically insulating layer has flexibility and is prevented from chipping or cracking, and a mechanically stable heat roller can be obtained. Since the linear expansion coefficient of the electrical insulating layer can be made substantially the same as that of the metal base, cracking or peeling due to the difference in linear expansion coefficient does not occur. Since the electrical insulating layer can be formed under low temperature conditions, it is easy to use aluminum as a metal substrate, which increases the degree of freedom in substrate material selection and design, lowering costs and increasing the fixing unit rise time. It becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat roller used in an image forming apparatus using an electrophotographic system.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, an image formed of a developer called toner is formed on a photoconductor, and the toner image is transferred onto paper and then fixed. By doing so, an image is formed. As the toner fixing method, there are a heat fixing method and a pressure fixing method, but the former method, particularly the heat roller fixing method, has become the mainstream.

In the heat roller fixing method, a heat roller is brought into contact with a transfer substrate such as a paper on which a toner image made of a toner containing a binder resin and a colorant is transferred and formed, and the toner is softened or melted to transfer the toner onto the transfer paper. It will be established in. As a heating method by a heat roller, various ones are known, but a heat roller in which a heating resistor layer is formed on the peripheral surface of a metal cylindrical substrate via an electric insulating layer has a uniform fixing temperature, It is excellent in that the rise time to the fixing temperature is short. The present invention relates to this type of heat roller. As this type of heat roller, for example, in JP-A-64-86185, an outer peripheral surface of a pipe made of iron, stainless steel, aluminum or the like is subjected to enamel processing for insulation, and Ni-P, Ni- WP,
A heat roller in which a heating resistance layer such as Ni-Cu-P is formed by electroless plating has been proposed, and it is also described that a Teflon layer is further provided on the surface thereof.

Further, in Japanese Patent Laid-Open No. 55-72390, heating resistance is provided on the inner peripheral surface or outer peripheral surface of a cylindrical substrate of copper alloy, aluminum alloy or the like via an electrically insulating layer made of silicone, mica, glass or the like. It is described that a body is provided to form a cylindrical heater, and its use in the fixing device is also described. However, in a conventional heat roller in which glass, enamel, ceramics, etc. are provided as an insulating layer on a metallic cylindrical substrate, there is a large difference in the coefficient of thermal expansion between the metallic substrate and the insulating layer, so fixing / fixing
There is a problem that peeling and cracking of the insulating layer are likely to occur due to repeated heat generation and cooling for standby. The coefficient of linear expansion of metals such as iron and aluminum is 10
˜30 × 10 ⁻⁶ / ° C., while the linear expansion coefficient of glass and ceramics is 3 to 5 × 10 ⁻⁶ / ° C.

Further, the electric insulating layer of glass, ceramics, enamel or the like needs to be formed by baking in a high temperature atmosphere of about 600 to 1200 ° C., so that the metallic cylindrical base body is damaged by softening, oxidation and the like. In particular, aluminum cannot be used as a thin wall tube because of its softening. Further, when iron is used, it is necessary to bake the insulating layer in a nitrogen atmosphere to prevent oxidation, which causes an increase in cost.

Further, since the insulating layer formed of glass or ceramics is vulnerable to impact force from the outside, during the manufacturing process of the heat roller, or when handling the heat roller as a single unit during transportation and assembly, etc. It has a drawback that the insulating layer is likely to be chipped or cracked.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a heat roller which does not require harsh conditions at the time of manufacture and has improved problems such as cracking and peeling of the electric insulating layer after the manufacture and during repeated use. It is a thing.

[0008]

The heat roller of the present invention is a heat roller in which a heating resistor layer is provided on the peripheral surface of a metallic cylindrical substrate through an electric insulating layer, and the electric insulating layer is made of an organometallic polymer. It is characterized by being formed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross sectional view showing a heat roller of the present invention. The heat roller is formed by sequentially forming an electric insulating layer 13, a heating resistor layer 15 and a surface coating layer 17 on the outer peripheral surface of a metallic cylindrical substrate 11, and the heating resistor layer 15 is formed.
Is provided with an electrode 21 for electrically heating. As a material of the metallic cylindrical substrate 11, a metal having good thermal conductivity such as aluminum, aluminum alloy, copper, copper alloy, iron, iron alloy can be used.

The electrically insulating layer 13 is made of an organometallic polymer. An organometallic polymer is a compound having a direct bond between metal and carbon, and is a polymer having two features of heat resistance and flexibility. For example, the main chain is formed from boron, silicon, and oxygen. There is a boron siloxane-based polymer, and an example of this basic structure is as shown in Chemical formula 1 below.

[0011]

[Chemical 1]

The boron siloxane-based polymer is, for example,
It is commercially available from Showa Densen Denpa Co., Ltd. under the trade name of Showekcel. The organometallic polymer is a heat resistant polymer having a withstand voltage, functions as an electric insulating layer, and can sufficiently withstand the heating by the heating resistor layer 15. In addition, the organometallic polymer has flexibility and is mechanically stable without being chipped or cracked by an external impact force.

Further, the organic metal polymer has a coefficient of linear expansion substantially the same as that of the metal substrate, and even if heat generation and cooling are repeated in the fixing operation, due to the difference in the coefficient of thermal expansion, the electrical insulating layer made of the organic metal polymer. It is prevented that 13 is peeled off from the metallic cylindrical substrate 11 and cracked. Also,
The electrically insulating layer 13 can be formed by applying an uncured organometallic polymer and heating and curing it at a relatively low temperature, so that the degree of freedom in selecting the metallic cylindrical substrate 11 is increased. For example, the aluminum base 11 that can be procured at a low cost including the processing cost can be used. Further, the thickness of the base 11 can be reduced.

The preheating of the heat roller during standby (when not in use) should be suppressed as much as possible from the viewpoint of energy saving, while at the time of startup (during image formation) it is necessary to rapidly rise to the set temperature. By reducing the thickness of the base 11, the heat capacity is lowered, and the fixing possible temperature time (rise time) of the fixing device can be shortened. Further, as described above, since the voltage insulating layer 13 made of the organometallic polymer can be formed under mild firing conditions, the surface condition of the metal base 11 is not roughened or dimensional deformation is less likely to occur at the time of formation, and high performance is achieved. A heat roller can be formed.

The thickness of the electric insulation layer 13 is preferably 10 to 200 μm, more preferably 20 to 100 μm, in consideration of electric insulation, man-hours for film formation, thermal conductivity and the like.
The heating resistor layer 15 is made of RuO ₂ , Ni-Cr alloy, N
It is formed from a paste having a metal powder of i, Cr, Cu or the like. The surface coating layer 17 covers the heating resistor layer 15 and is made of a fluororesin such as PFA or PTFE in order to prevent toner from adhering to the heat roller side during transfer.

In the above description, the case where the electrically insulating layer 13 and the heating resistor layer 15 are formed on the outer peripheral surface of the cylindrical substrate 11 to form a heat roller has been described. It can also be formed on the peripheral surface. Also in this case, it is desirable to form a surface coating layer made of fluororesin on the outermost peripheral surface (front surface) of the heat roller in order to prevent toner adhesion. The heat roller of the present invention can be suitably used as a heat fixing roller of a fixing device in an image forming apparatus using an electrophotographic system such as a copying machine and a printer.

[0017]

According to the present invention, in a heat roller in which a resistance heating element layer is provided on the peripheral surface of a metallic cylindrical substrate with an electric insulation layer interposed therebetween, by using an organometallic polymer as the electric insulation layer, The effect is obtained. (1) The electrically insulating layer has flexibility and is prevented from being chipped or cracked, and a mechanically stable heat roller can be obtained. (2) Since the linear expansion coefficient of the electrical insulating layer can be made substantially the same as that of the metal base, cracking or peeling due to the difference in linear expansion coefficient does not occur unlike in the case of glass, ceramics, and enamel. (3) Since the electric insulating layer can be formed under a relatively low temperature condition, it is easy to use aluminum as the metal base, and the degree of freedom in selecting the base material and designing is increased. It is possible to speed up the rise time of the.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of a heat roller of the present invention.

[Explanation of symbols]

 11 Metal Cylindrical Substrate 13 Electric Insulation Layer 15 Resistance Heating Element Layer 17 Surface Covering Layer 21 Electrode

Front page continuation (72) Inventor Takahiro Maruyama 1-1 Yamashita-cho, Kokubun-shi, Kagoshima Prefecture Kyocera Stock Company, Kokubun Plant (72) Inventor Hiro Takenouchi 1-1 Yamashita-cho, Kokubun-shi, Kagoshima Prefecture Kyocera Stock Company, Kokubun Plant (72 Inventor Hiroaki Naokawa 2-14-9 Tamagawadai, Setagaya-ku, Tokyo Kyocera Corporation Tokyo Yoga Works

Claims (1)

[Claims] 1. A heat roller in which a heating resistor layer is provided on the peripheral surface of a metallic cylindrical substrate with an electric insulating layer interposed therebetween, wherein the electric insulating layer is formed of an organometallic polymer. .