JP2007298855A - Heat roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat roller shortening warming up time and with remarkable productivity. <P>SOLUTION: A cylindrical pipe (2) of ceramic material is used as base material in the heat roller and a heat generating body pattern (3) is formed by metal plating on an outer circumference surface of the ceramic pipe (2). A fluororesin tube (4) is attached on the outer circumference surface of the ceramic pipe (2) to cover the heat generating pattern. The fluororesin tube functions as a heat dispersing layer and also functions as a mold releasing material layer. Since thermal conductivity is low in the ceramic material, generated heat is transmitted to fluororesin tube side and the heat roller with shortened warming up time is obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat roller used in a heat roll fixing apparatus, and more particularly to a heat roller having a significantly shortened wait time.

  In various printer apparatuses, a heat roll fixing apparatus is widely used to fix a toner image formed on a recording sheet. The heat roll fixing device has a heat roller and a pressure roller, presses the heat roller against the pressure roller to form a nip, and heat generated from the heat roller while the recording paper passes through the nip. The toner on the recording paper is fused. The heat roll fixing device has an advantage that the toner on the recording paper can be stably fixed, but the heat capacity of the heat roller is large, so there is a disadvantage that it takes a warm-up time until the copy is ready after the power is turned on. .

  A belt fixing device is known as a fixing device that shortens the warm-up time (see, for example, Patent Document 1). This belt fixing device uses a fixing belt in which a sheet heating element is bonded to a polyimide belt base material, and a fixing belt is mounted between a pressure roller and a power supply roller, and heat generated from the fixing belt is used. The toner on the recording paper is fixed.

JP 2000-66539 A

  The belt fixing device has an advantage that the warm-up time is shortened because the heat capacity is small. However, the fixing belt is likely to meander during traveling, and it is difficult to stably run the fixing belt, and there is a drawback in that the fixing belt lacks running stability and paper passing performance. On the other hand, the heat roll fixing device has an advantage that the recording paper can be stably conveyed because the toner is fixed only by passing the recording paper between the two rollers. Therefore, if a fixing belt having a heating element is mounted on the outer peripheral surface of the roller, the advantages of shortening the warm-up time and fixing the recording paper stably are achieved. However, in order to mount the fixing belt on the roller, a sheet heating element must be adhered on the belt base material and further mounted on the roller. Therefore, workability is poor and mass productivity is problematic.

  The planar heating element is formed by forming a resistance heating element on a polyimide film by a transfer process. However, when the heating element pattern is formed by the transfer process, there is a limit to the control of the thickness of the resistance heating element, which makes it difficult to form the resistance heating element having a desired pattern, and the degree of freedom in design is limited. It was. Furthermore, the bonding strength between the polyimide film surface and the resistance heating element is limited, and problems such as peeling of the heating element pattern have been pointed out.

An object of the present invention is to provide a heat roller having a reduced warm-up time and excellent productivity.
Another object of the present invention is to provide a heat roller capable of forming a heating element pattern having a desired thickness and further improving the degree of freedom in designing the heating element pattern.
Another object of the present invention is to provide a heat roller having improved durability and improved durability between a heating element pattern and a substrate.

The heat roller according to the present invention is made of a ceramic material, and an electrically insulating cylindrical pipe;
A heating element pattern formed by plating on the outer peripheral surface of the cylindrical pipe;
Mounted on the outer peripheral surface of the cylindrical pipe so as to cover the heating element pattern, an electrically insulating fluororesin tube,
The power supply terminal is provided at both ends of the cylindrical pipe, and supplies power to the heating element pattern.

  In the present invention, the heating element pattern is directly formed on the outer peripheral surface of the ceramic cylindrical substrate by plating. Since the ceramic material has low thermal conductivity, heat generated from the heating element pattern is transmitted to the outer fluororesin tube. Since the fluororesin tube functions as a release material layer as well as performing a thermal diffusion action, the outer peripheral surface of the fluororesin tube is set to a substantially uniform temperature. As a result, a heat roller with a short warm-up time is realized.

  Furthermore, in the plating process, since the thickness of the plating layer is controlled by the immersion time in the plating tank, the thickness and resistance value of the heating element pattern can be controlled with high accuracy. Further, when a conductive material layer such as nickel / chrome is formed on the surface of the ceramic material by plating, there is an advantage that high bonding strength can be obtained between the surface of the ceramic and the conductive film.

  In the present invention, it is also possible to interpose an electrically insulating elastic rubber layer as a heat diffusion layer between the heating element pattern and the fluororesin layer (fluororesin tube). For example, if the heating element pattern is covered with a heat-resistant elastic rubber layer such as silicon rubber and a release material layer is formed on the outer peripheral surface thereof, the silicon rubber layer elastically deforms when the temperature rises. The problem due to is resolved.

  In the present invention, since the heating element pattern is formed on the ceramic base material by plating, a heat roller having a greatly shortened warm-up time can be realized. In particular, in the plating process, since the film thickness of the heating element pattern can be freely controlled by controlling the immersion time in the plating tank, the degree of freedom in design is improved. In addition, since the adhesion strength between the ceramic material and the resistance heating element is high, the occurrence of defects such as peeling of the heating element pattern is prevented.

  FIG. 1 is a diagrammatic sectional view showing an example of a heat roller according to the present invention. The heat roller 1 includes a cylindrical pipe 2 serving as a base material. The cylindrical pipe 2 is made of an electrically insulating ceramic material. Various ceramic materials can be used as the ceramic material, and an electrically insulating ceramic material such as alumina ceramic or cement is used.

  A resistance heating element pattern 3 is formed on the outer peripheral surface of a cylindrical pipe 2 as a base material. For the heating element pattern 3, various resistance heating element materials such as nickel, chromium, nickel / chromium alloy, conductive ceramic, and carbon-containing conductive material are used. In the present invention, the heating element pattern 3 is not formed by transfer or printing, but is formed on the outer peripheral surface of the cylindrical pipe by plating. That is, a cylindrical pipe made of ceramic material is masked and immersed in a plating tank, and the plating process time is controlled to form a heating element pattern having a predetermined film thickness. At this time, since the thickness of the resistance heating element to be formed can be controlled with high accuracy by the immersion time in the plating tank, the resistance value of the heating element pattern is controlled by controlling the immersion time in the plating tank. It can be set to a desired resistance value. Furthermore, if the heating element pattern is formed by plating, the bonding strength between the ceramic pipe 2 as a base material and the resistance heating element is good, the heating element is difficult to peel off from the base material surface, and the durability of the heat roller is also improved. Is done.

  The pattern shape of the heating element pattern 3 can be formed into a desired shape by masking. For example, a conductor pattern or a linear conductor pattern extending in parallel with the roller axis at a predetermined interval can be formed around the roller axis.

  A fluororesin tube 4 is mounted on the outer peripheral surface of the cylindrical pipe 2 so as to cover the heating element pattern 3. In this example, the fluororesin tube 4 is a relatively thick tube having a thickness of 200 μm or more, and the heat generated from the heating element 3 is diffused by the fluororesin tube. Since the heat generated by the heating element 3 is thermally diffused by the relatively thick fluororesin tube, a substantially uniform temperature distribution is formed on the outer peripheral surface of the fluororesin tube. In addition, since the fluororesin has a high releasability, it also functions as a release material layer that prevents toner adhesion. Furthermore, since the fluororesin tube is electrically insulative, the occurrence of leakage etc. is prevented. It is also possible to form an insulating layer of an electrically insulative heat-resistant paint on the surface of the heating element pattern and mount a fluororesin tube thereon.

  Power supply terminals 5 a and 5 b for supplying power to the heating element pattern 3 are attached to both ends of the cylindrical pipe 2. These power supply terminals are made of conductive metal and function as power supply terminals as well as boss members. That is, by connecting the power supply terminals 5a and 5b, which also function as boss members, to a support member such as a frame via an insulating bearing and to a drive system via an insulating material, the rotational driving force is applied to the heat roller 1. Can be communicated to. At the same time, it is possible to supply power to the heating element pattern from an external power source by connecting a brush to the power supply terminal. It is possible to form both ends of the heating element pattern 3 up to the end face of the cylindrical pipe 2 and to be electrically connected to the power supply terminals 5a and 5b via the extensions 6a and 6b.

  FIG. 2 is a diagrammatic sectional view showing a modification of the heat roller according to the present invention. In this example, the thermal diffusion layer 10 is formed on the cylindrical pipe 2 so as to cover the heating element pattern 3. As the thermal diffusion layer, an elastically deformable rubber material layer that is electrically insulative and heat resistant, such as silicon rubber or fluorine rubber, is used. A release material layer 11 such as a fluororesin layer (for example, PFA, PTFA) or a fluororesin tube is formed on the thermal diffusion layer 10. By providing the thermal diffusion layer of the elastic rubber material, the temperature of the outer peripheral surface of the fluororesin tube can be made more uniform. The heat roller is heated to 160 to 180 ° C. during use. In this case, even if there is a difference in thermal expansion coefficient, the problem due to the difference in thermal expansion coefficient can be eliminated by interposing a rubber layer having heat resistance and elastically deformable. It is also possible to form an electrically insulating heat-resistant paint layer on the heating element pattern 3 and to form a diffusion layer of an elastic rubber layer thereon.

  FIG. 3 is a plan view showing a modification of the heating element pattern of the heat roller according to the present invention. In this example, the heating element pattern 3 includes a plurality of heating element narrow shapes 3a that extend linearly in parallel to the roller axis, and an annular portion 3b that is formed at both ends of the heating element narrow shape 3a and extends in an annular shape. And 3c. The annular portions 3b and 3c extend to the side surface of the cylindrical pipe, and electrically connect the heating element strip and the power supply terminals 5a and 5b. By forming an elastic rubber layer functioning as a heat diffusion layer so as to cover the heating element pattern 3 and covering the thin fluorine tube thereon, the outer peripheral surface of the heat roller can be heated to a more uniform temperature.

  The heat roller shown in FIGS. 1 and 2 is mounted so as to be in pressure contact with the pressure roller via a pressure bonding mechanism, thereby realizing a heat roll fixing device.

It is a diagrammatic sectional view showing an example of a heat roller according to the present invention. It is a diagrammatic sectional view showing a modification of the heat roller according to the present invention. It is a top view which shows the modification of a heat generating body pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat roller 2 Cylindrical pipe 3 Heating element pattern 4 Fluororesin tube 10 Thermal diffusion layer 11 Release material layer

Claims (4)

A cylindrical pipe made of ceramic material and electrically insulating;
A heating element pattern formed by plating on the outer peripheral surface of the cylindrical pipe;
Mounted on the outer peripheral surface of the cylindrical pipe so as to cover the heating element pattern, an electrically insulating fluororesin tube,
A heat roller comprising power supply terminals provided at both ends of the cylindrical pipe, respectively, for supplying power to the heating element pattern. A cylindrical pipe made of ceramic material and electrically insulating;
A heating element pattern formed by plating on the outer peripheral surface of the cylindrical pipe;
An electrically insulating rubber layer formed on the outer peripheral surface of the cylindrical pipe so as to cover the heating element pattern and diffusing heat generated from the heating element pattern;
A release layer or fluororesin tube formed on the rubber layer;
A heat roller comprising power supply terminals provided at both ends of the cylindrical pipe, respectively, for supplying power to the heating element pattern.   3. The heat roller according to claim 1, wherein the heating element pattern is formed on an outer peripheral surface of a cylindrical pipe made of a ceramic material by an electroless plating process. The heat roller according to any one of claims 1 to 3, wherein the heating element pattern includes a plurality of heating element strips extending linearly in parallel with a roller axis, and both ends of the heating element strips. And a circular portion extending in an annular shape and electrically connecting the heating element strip and the power supply terminal.