JP2006344532A - Heating roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a rise time and to improve thermal responsiveness of a heating roller for conveying a workpiece while heating it by heating the outer surface of the heating roller to a predetermined temperature. <P>SOLUTION: A carbon graphite sheet is spirally wound around the outer peripheral part of a roller body 10 of the heating roller through a heat insulating layer 17 to form a carbon graphite layer 18, and a current is applied to the carbon graphite layer 18 to heat the outer surface of the heating roller to the predetermined temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heating roll, and more particularly to a heating roll provided with a heating means.

  When pressurizing the workpiece by the roll, a heating roll is used in order to set the surface temperature of the roll itself to a predetermined temperature and thereby heat the workpiece. Such a heating roll has a heating means inside, and the surface temperature is set to a predetermined temperature by the heat generated by the heating means.

  One of the conditions required for such a heating roll is to shorten the startup time. This is a condition determined by how long it takes to reach a predetermined temperature after starting energization. In order to shorten such start-up time, as disclosed in, for example, Japanese Patent Laid-Open No. 10-48986, a thin film of a heating element made of EL is formed on the outer peripheral surface of the roll, or Japanese Patent Laid-Open No. 2001-2001 As disclosed in Japanese Patent No. 313160, measures such as forming a magnetic metal layer that generates Joule heat by an induced current on the surface of the core metal are taken. Alternatively, as disclosed in JP-A-9-62131, a heat-resistant elastic body layer is provided on the outer peripheral surface of the fixing roll cylinder via a gap, and a fluid having good heat conductivity, such as silicon, is provided in the gap. Oil and fine powder of carbon graphite are enclosed.

However, even with the various measures described above, there is a problem that the start-up time is not sufficiently shortened and the intended purpose cannot always be achieved.
Japanese Patent Laid-Open No. 10-48986 JP 2001-313160 A JP-A-9-62131

  The subject of this invention is providing the heating roll with short start-up time.

  Another object of the present invention is to provide a heating roll having high energy conversion efficiency, less power consumption, and capable of maintaining the surface temperature at a desired temperature.

  Still another object of the present invention is to provide a heating roll excellent in thermal responsiveness at startup.

  Yet another object of the present invention is to provide a heating roll that can significantly shorten the heat-up time.

  Still another object of the present invention is to provide a heating roll that is lightweight and has a short start-up time.

  The above-described problems and other problems of the present application will be made clear by the technical idea of the present invention and the embodiments thereof described below.

The main invention of the present application is a heating roll provided with heating means,
The present invention relates to a heating roll characterized in that the heating means is carbon graphite. Here, sheet-like carbon graphite may be wound around the outer periphery to serve as a heating means, and the carbon graphite may be energized to generate heat. Alternatively, a carbon graphite sheet having electrodes on both sides may be wound around the outer periphery to form a heat generating means, and a high frequency voltage may be applied to the electrodes on both sides to heat the carbon graphite sheet by dielectric heating.

  Carbon graphite heat generating means may be provided on the outer periphery of the roller body through a heat insulating layer. The heat insulating layer may be a bonded molded body of polyimide balloon. The heat insulating layer may be a ceramic layer. The heat insulating layer may be a foamed resin layer. Further, a rubber sheet may be coated on the outer peripheral portion of the heating means made of carbon graphite. Alternatively, a predetermined portion of the carbon graphite sheet may be connected to a lead wire, and connected to an external drive circuit via a slip ring to be energized. Further, predetermined portions of the electrodes on both sides may be connected to a lead wire and connected to an external high frequency power supply circuit via a slip ring.

  The main invention of the present application relates to a heating roll provided with a heating means, wherein the heating means is carbon graphite.

  Therefore, according to such a heating roll, it is possible to shorten the start-up time of the heating roll and improve the responsiveness by utilizing the good thermal conductivity of the carbon graphite itself. Therefore, the time from the start of energization until reaching a predetermined temperature can be greatly shortened.

  In particular, according to a configuration in which sheet-like carbon graphite is wound around the outer periphery to serve as a heat generating means, and the carbon graphite is heated by generating electricity, the carbon graphite sheet generates heat due to Joule heat, which causes the heating roll to While being heated effectively, the start-up time can be greatly shortened.

  In addition, according to the configuration in which the carbon graphite sheet having electrodes on both sides is wound around the outer peripheral portion as a heating means, and the carbon graphite sheet is heated by dielectric heating by applying a high frequency voltage to the electrodes on both sides, the electrodes on both sides The carbon graphite sheet having the structure constitutes a capacitor, and heat is generated by the principle of dielectric heating due to the dielectric loss caused by the high frequency voltage applied to the capacitor, thereby effectively heating the roll. Moreover, such heating can significantly reduce the heat-up time.

  The present invention will be described below with reference to embodiments shown in the drawings. As shown in FIGS. 1 and 2, the heating roll of the present embodiment is hollow and includes a roll body 10 having a predetermined diameter. The roll body 10 has flanges 11 and 12 fixed to both ends thereof, and a hollow shaft 13 is attached so as to penetrate the flanges 11 and 12.

  A carbon graphite layer 18 is formed on the outer peripheral surface of the roll body 10 of such a heating roll via a heat insulating layer 17. Here, the gap between the carbon graphite layers 18 is filled with an insulating resin 19 such as an epoxy resin. Then, the covering rubber 20 is attached so as to cover the outer peripheral side of the carbon graphite layer 18.

  Here, the heat insulating layer 17 is formed by bonding polyimide hollow balloons to each other to form a cylindrical shape. A heat generating layer made of a carbon graphite sheet 18 is formed on the outer peripheral surface of the heat insulating layer 17 made of such a polyimide hollow balloon.

  Here, the polyimide balloon constituting the heat insulating layer 17 (see FIG. 3) is produced by reacting dianhydride such as ODPA, BTDA, PMDA, and diamine such as ODA, PDA, DDS, etc. It is a lightweight granule having a density of 0.3 to 0.8 mm, a density of 1.5 to 2.5 pcs, a glass transition temperature of 299 ° C., and a heat resistant temperature of 300 ° C. or higher. Such a balloon is supplied as a trade name TEEK from Unitika Co., Ltd., for example. Such particles are joined to each other with a heat resistant resin, thereby forming the panel 10.

  As described above, the polyimide balloon is a hollow particle having a particle size of 0.3 to 0.8 mm, has fine bubbles effective for heat insulation, and has a heat insulation equivalent to a resin heat insulating material such as urethane or styrene. Has characteristics. That is, the value is 0.02-0.04 W / mK. Moreover, it is a highly flame-retardant material, and there is little shape change with respect to a flame. Moreover, since it is a structure of the above composition and is a wholly aromatic polyimide, it has the property excellent in chemical resistance and electrical insulation. Furthermore, it has excellent durability against electron beams and radiation. Moreover, such a hollow balloon is a foam molded from a balloon obtained in an intermediate process of polyimide foam molding, and enables molding of a three-dimensional shape and filling of a complicated internal space.

  On the other hand, the carbon graphite sheet 18 joined to the outer peripheral side is a natural carbon-based material. Carbon exists stably in the form of diamond, graphite (graphite), and amorphous carbon. In particular, the graphite is black and opaque, has a hexagonal crystal structure, and is an electrical and thermal conductor. In particular, a graphite sheet can be obtained by rolling naturally occurring graphite. Graphite sheets produced by rolling from natural graphite are characterized by low cost.

  When an organic synthetic film such as an acrylic resin film using acrylonitrile is baked in the absence of oxygen instead of using natural graphite, a sheet-like graphite is obtained. A graphite sheet made of a polymer material has the advantages of flexibility and compression elasticity and good compatibility with the other party. Therefore, as the carbon graphite sheet 18 joined to the outer peripheral side of the heat insulating layer 17, a graphite sheet obtained by firing acrylonitrile or the like can be used in addition to those manufactured from natural graphite.

  As described above, the carbon graphite layer 18 is formed on the outer surface of the heat insulation layer 17 by winding the ribbon-like carbon graphite sheet. This carbon graphite layer 18 constitutes a heat generating means. For energization, lead wires 23 and 24 are connected to both ends of the sheet constituting the carbon graphite layer, respectively. These lead wires 23 and 24 pass through the hollow portion of the hollow shaft 13 and are connected to the conductor patterns 27 and 28 of the slip ring 26 attached to the end of the hollow shaft 13. The conductor patterns 27 and 28 are in sliding contact with the fixed brushes 29 and 30, respectively.

  Here, a carbon graphite sheet 18 in the form of a ribbon is wound to form a carbon graphite layer 18. However, such a carbon graphite layer 18 is used for insulation between adjacent carbon graphite layers 18. Insulated by a material with excellent insulating properties. Examples of insulating materials that can be used include liquid crystal films, liquid crystal paints, epoxy paints, polyamide films, kapton films, ten films, two-layer polyethylene terephthalate films, melamine films, various other resin paints and resin films, and nylon films. It's okay. In addition, it is possible to insulate with a glass cloth. Furthermore, the carbon graphite layers 18 may be insulated by a ceramic coating.

  Therefore, according to the heating roll having such a configuration, when the brushes 29 and 30 are brought into sliding contact with the conductor patterns 27 and 28 of the slip ring 26 while rotating the heating roll, the brushes 29 and 30 and the conductor patterns 27 and 28 are passed through. Electricity is supplied from the lead wires 23 and 24 to the carbon graphite layer 18. Therefore, the carbon graphite 18 itself generates heat by this energization. Since the carbon graphite layer 18 is in contact with the heat insulating layer 17 on the inner side, it is difficult for heat to be transferred to the inner side. For this reason, the temperature on the outer peripheral side coated with the covering rubber 20 rapidly increases. In particular, since the carbon graphite layer 18 itself has high heat transfer properties, the carbon graphite layer 18 reaches a predetermined temperature in a very short time, and the start-up time can be remarkably shortened. Moreover, since it has a small heat capacity and is insulated by the heat insulating layer 17, it has a feature of extremely low power consumption.

  In the above embodiment, a polyimide foam molded body is used as the heat insulating layer 17, but instead of such a configuration, as shown in FIG. Also good. Alternatively, as shown in FIG. 5, a heat insulating layer made of the foamed resin layer 34 may be used.

  Further, in the above embodiment, as shown in FIG. 1, the carbon graphite layer 18 is formed by winding the carbon graphite having a ribbon shape around the outer surface of the roll spirally. Instead, as shown in FIG. 6, a carbon graphite sheet having a width substantially equal to the entire length of the roll may be wound directly on the surface of the heat insulating layer 17. Also in this case, by connecting the lead wires 23 and 24 to both ends in the axial direction, energization is performed in the length direction of the roll, and the carbon graphite layer 18 generates heat by Joule heat.

  Such a heating roll can be used, for example, as a heating-type fixing roll of a copying machine, but can also be widely used as a roll that performs heating while applying pressure. Depending on the purpose, the outer diameter and length of the roll can be changed to various dimensions.

  Next, another embodiment will be described with reference to FIGS. In this embodiment, the carbon graphite sheet 40 made of sheet-like carbon graphite and the electrodes 41 and 42 on both sides generate heat by dielectric heating.

  On the roll body 10 through which the hollow shaft 13 penetrates the central part, a heat insulating layer 17 similar to that of the above embodiment is formed, and on the outer peripheral side of the heat insulating layer 17, a space between concentric electrodes 41 and 42 is formed. A dielectric heating means having a carbon graphite layer 14 disposed thereon is disposed. A covering rubber 43 is attached to the outer peripheral side of the outer electrode 42 to constitute a heating roll. The inner and outer electrodes 41 and 42 are connected to the high frequency power supply circuit 45 via the lead wires and the slip ring 26 of the above embodiment.

  As described above, when the carbon graphite layer 40 constituting the dielectric is inserted between the opposing electrodes 41 and 42 on both sides and a uniform high-frequency electric field E [V / cm] is applied, the electric power given by the following formula in the dielectric is obtained. Is consumed.

Po = KE ² = (5/9) · fε _s tan δ · E ² × 10 ⁻¹² [W / cm ³ ]
Here, K: equivalent conductivity [Ω ⁻¹ · cm ⁻¹ ], f: frequency [Hz], ε _s : relative permittivity, and δ: dielectric loss angle.

Thus, the power consumption, that is, the amount of heat generation, is proportional to the frequency f, the square of the electric field strength E, and ε _s · tan δ regardless of the size and shape of the dielectric. Here, ε _s · tan δ is called a loss coefficient, and is determined by the type, nature, state, temperature, and frequency of the dielectric.

  Therefore, according to such a carbon graphite sheet 40, a high-frequency voltage is applied to the electrodes 41 and 42 on both sides via the slip ring 26 by the high-frequency power circuit 45, thereby being sandwiched between the electrodes 41 and 42 on both sides. When a uniform high-frequency electric field is applied to the carbon graphite layer 40, power is consumed due to the internal loss of the carbon graphite layer 40 itself, and the carbon graphite layer 40 itself generates heat as the power is consumed. .

  Such heat generation is generated immediately below the covering rubber 43 and at the outer peripheral portion of the roll. In addition, since the heat insulating layer 17 is interposed on the center side, heat does not escape to the center side, thereby enabling the outer periphery of the roll to be effectively heated. In addition, since such a heating roll is heated by the heat generation of the carbon graphite layer 40 itself constituting the dielectric, no heat transfer material is interposed, and the temperature can be raised in a very short time. The start-up time is shortened and the heat-up time can be remarkably shortened. Such a roll can also be used as, for example, a heating fixing roll of a copying machine.

  Such a heating roll can be used, for example, as a heating-type fixing roll of a copying machine, but can also be widely used as a roll that performs heating while applying pressure. Depending on the purpose, the outer diameter and length of the roll can be changed to various dimensions.

  The present invention can be used as a heating roll for heating a workpiece such as a fixing roll of a copying machine.

It is the principal part perspective view which fractured | ruptured some coating rubber | gum of a heating roll. It is a longitudinal cross-sectional view of the heating roll. It is an expanded sectional view of the part of the perimeter side of the heating roll. It is a principal part expanded sectional view of the outer peripheral part of the heating roll which used the ceramic layer as a heat insulation layer. It is a principal part expanded sectional view of the outer peripheral part of the heating roll using the foamed resin layer as a heat insulation layer. It is an external appearance perspective view which shows winding of the carbon graphite sheet of the heating roll of a modification. It is sectional drawing in a surface perpendicular | vertical to the axial center of the heating roll of another embodiment. It is an expanded sectional view of the part of the perimeter side of the heating roll.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Roll body 11, 12 Flange 13 Hollow shaft 17 Heat insulation layer 18 Carbon graphite layer 19 Insulation resin 20 Cover rubber 23, 24 Lead wire 26 Slip ring 27, 28 Conductive pattern 29, 30 Brush 33 Heat insulation ceramic layer 34 Foamed resin layer 40 Carbon Graphite layer 41, 42 Electrode 43 Coated rubber 45 High frequency power circuit

Claims (10)

In a heating roll provided with a heating means,
A heating roll, wherein the heat generating means is carbon graphite.   The heating roll according to claim 1, wherein sheet-like carbon graphite is wound around an outer peripheral portion to form a heat generating means, and the carbon graphite is energized to generate heat.   2. A carbon graphite sheet having electrodes on both sides is wound around an outer peripheral portion to form a heating means, and a high frequency voltage is applied to the electrodes on both sides to heat the carbon graphite sheet by dielectric heating. The heating roll described.   The heating roll according to claim 2 or 3, wherein the heat generating means of carbon graphite is provided on the outer peripheral portion of the roller body through a heat insulating layer.   The heating roll according to claim 3, wherein the heat insulating layer is a bonded molded body of a polyimide balloon.   The heating roll according to claim 3, wherein the heat insulating layer is a ceramic layer.   The heat roll according to claim 3, wherein the heat insulating layer is a foamed resin layer.   The heating roll according to any one of claims 1 to 3, wherein a rubber sheet is coated on an outer peripheral portion of the heating means made of carbon graphite.   The heating roll according to claim 2, wherein a predetermined portion of the carbon graphite sheet is connected to a lead wire, and is connected to an external drive circuit via a slip ring to be energized. The heating roll according to claim 3, wherein predetermined portions of the electrodes on both sides are connected to a lead wire and are connected to an external high-frequency power circuit through a slip ring.

Images