JP4760901B2 - Method for producing heat equalizing member for fixing device and heat equalizing member for fixing device - Google Patents

Description

  The present invention relates to a method for manufacturing a soaking member for a fixing device, and more particularly to a method for producing a soaking member used for a fixing device in an electrophotographic image forming apparatus (a copying machine or a printer).

  The present invention also relates to a heat equalizing member for such a fixing device.

In a fixing device used in an image forming apparatus such as an electrophotographic copying machine or a printer, a roller or belt having a low heat capacity is used as a fixing member for heating and / or pressurizing a conveyed sheet in order to shorten a warm-up time. Is often used. When such a low heat capacity roller or belt is used, the temperature rises faster, but heat transfer hardly occurs in the longitudinal direction of the roller (belt width direction). For this reason, a heat pipe in which a working fluid (water, etc.) is sealed in a pipe of a metal (copper, aluminum, etc.) with good heat conduction along the roller and belt is disposed and pressed as a soaking member. As a result, by utilizing the latent heat of the working fluid sealed in the heat pipe, the temperature distribution difference in the longitudinal direction of the roller (the width direction of the belt) is reduced, and the temperature is equalized.
JP-A-7-28351

  By the way, when a heat pipe is directly pressed against a fixing member such as a roller or a belt, toner or paper powder slightly offset at the time of image fixing adheres to the surface of the heat pipe as dirt. If toner or paper powder accumulates on the surface of the heat pipe, the heat pipe cannot be uniformly contacted with the fixing member, and the soaking effect is reduced. In addition, there is a problem that accumulated dirt is dropped and the image on the sheet becomes dirty.

  Accordingly, a means for preventing contamination by forming a heat-resistant release layer made of a fluororesin on the surface of the heat pipe can be considered. When providing such a heat-resistant release layer made of a fluororesin, it is generally assumed that a commercially available heat pipe is coated with the fluororesin and then fired. However, there is a danger that the internal pressure of the heat pipe may rise and burst or break during firing. Also, the yield is impaired.

  In addition, it has been devised that a heat-resistant release layer made of a fluororesin covered with a reinforcing cylinder made of a rigid metal (stainless steel, iron, etc.) is externally fitted to a heat pipe and used as a soaking member. (JP-A-7-28351). However, in such a configuration, the thermal conductivity of the soaking member as a whole is lowered, and soaking performance is lowered. Further, since the extra heat capacity of the reinforcing cylinder is added to the heat pipe, the heat capacity increases and the warm-up time increases. Furthermore, since a reinforcing cylinder is used separately from the heat pipe, there arises a problem of high cost.

  Accordingly, an object of the present invention is to provide a heat equalizing member for a fixing device that can be manufactured safely, in a high yield, and at a low cost. It is providing the manufacturing method of a member.

  Another object of the present invention is to provide a heat-equalizing member for a fixing device that is less likely to get dirt on the surface, has good heat-uniforming performance, has a small heat capacity, and is inexpensive.

In order to solve the above problems, a method for producing a heat equalizing member for a fixing device according to the present invention includes
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe by firing ,
Through the other end of the pipe in which the heat-resistant release layer is formed , a working fluid is injected into the pipe from the outside ,
Thereafter, welding is performed to seal the other end.

  In this specification, “heat-resistant release layer” means durability against heat at a temperature suitable for fixing by a fixing device, and peeling of toner, paper powder, etc. compared to the metal material of the underlying pipe Means a layer having the property of being easily processed.

  The “operating fluid” is a liquid enclosed (or enclosed) in the pipe that reduces a difference in temperature distribution in the longitudinal direction of the pipe due to latent heat during evaporation and condensation (water Etc.).

  “Welding” is a concept including brazing.

In the method for producing a heat equalizing member for a fixing device according to the present invention, after the heat-resistant release layer is formed on the outer peripheral surface of the pipe by firing , the working liquid is injected into the pipe to seal the pipe. Therefore, when the heat-resistant release layer is formed by firing , the internal pressure of the pipe is not increased and is not ruptured or damaged. Therefore, according to this manufacturing method, the heat equalizing member for the fixing device is manufactured safely and with a high yield. Further, according to this manufacturing method, since the number of members is small as compared with the conventional example (Japanese Patent Laid-Open No. 7-28351) using the reinforcing cylinder, the heat equalizing member for the fixing device is manufactured at a low cost. Since the produced soaking | uniform-heating member has the said heat-resistant release layer in the outermost periphery, it is hard to adhere dirt on the surface. Moreover, since the produced heat equalizing member has the said pipe and the said heat-resistant release layer closely_contact | adhered, heat equalization performance is favorable and there is little heat capacity. In addition, the heat-resistant release layer of the heat equalizing member has durability against heat at a temperature suitable for fixing by the fixing device, and therefore, the fixing member for heating and / or pressurizing the conveyed sheet. Thus, the soaking member can stably maintain contact over a long period of time. Therefore, the soaking effect is stabilized and sustained.

  In the method for manufacturing a heat equalizing member for a fixing device according to an embodiment, after the heat-resistant release layer is formed and before the working fluid is injected, a first plastic working is performed, and the other end of the pipe is reduced in diameter. It is characterized by doing.

  In the method for manufacturing a heat equalizing member for a fixing device according to this embodiment, the injected hydraulic fluid is less likely to spill from the pipe during and after the injection of the hydraulic fluid.

  In the method for manufacturing a heat equalizing member for a fixing device according to an embodiment, when the other end of the pipe is sealed, a second plastic working is performed, and after the other end of the pipe is closed, the welding is performed. It is characterized by performing.

  In the manufacturing method of the heat equalizing member for a fixing device according to this embodiment, the other end of the pipe is reduced in diameter by the first plastic working. The other end can be easily closed.

In the method of manufacturing a heat equalizing member for a fixing device according to one embodiment,
Of the outer peripheral surface of the pipe, the region for forming the heat-resistant release layer is only an inner region excluding outer end regions at both ends with respect to the longitudinal direction of the pipe,
When performing the welding, a heat dissipation tool is brought into contact with the outer end region on the other end side of the pipe, and heat is released from the outer end region through the heat dissipation tool.

  In the present specification, the “outer end region” of the pipe refers to a region other than the inner region through which a predetermined maximum size sheet (recording material) passes in the fixing device using the heat equalizing member for the fixing device. That is, it corresponds to a region that does not contribute to fixing of the toner image.

  In the method for manufacturing a heat equalizing member for a fixing device according to this embodiment, when performing the welding, a heat radiating tool is brought into contact with the outer end region on the other end side of the pipe so that the heat dissipation is performed from the outer end region. Dissipate heat through the tool. Therefore, it is possible to prevent the heat-resistant release layer from being deteriorated by the heat of the welding, or the internal pressure of the pipe from being increased to be ruptured or broken.

In another aspect, a method for producing a heat equalizing member for a fixing device according to the present invention includes:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by performing powder electrostatic coating of fluororesin on the outer peripheral surface of the internal region of the pipe and then firing the fluororesin.

In the method for manufacturing a heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, a method for producing a heat equalizing member for a fixing device according to the present invention includes:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by applying a dispersion paint in which a fluororesin powder is dispersed in water on the outer peripheral surface of the inner region of the pipe, and then baking the dispersion paint. And

In the method for manufacturing a heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, a method for producing a heat equalizing member for a fixing device according to the present invention includes:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by covering the outer peripheral surface of the inner region of the pipe with a tube made of a fluororesin and then firing the tube.

In the method for manufacturing a heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, a method for producing a heat equalizing member for a fixing device according to the present invention includes:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by immersing the outer peripheral surface of the inner region of the pipe in a molten fluororesin, causing the fluororesin to adhere around the outer peripheral surface, and the fluorine adhering around the outer peripheral surface. After the resin film thickness is made constant by using a film thickness regulating blade, the fluororesin is baked.

In the method for manufacturing a heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, a method for producing a heat equalizing member for a fixing device according to the present invention includes:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by applying a molten fluororesin to the outer peripheral surface of the internal region of the pipe using a roll coater and then firing the fluororesin.

In the method for manufacturing a heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In the method for manufacturing a heat equalizing member for a fixing device according to an embodiment, after the heat-resistant release layer is formed and before the working fluid is injected, a first plastic working is performed, and the other end of the pipe is reduced in diameter. It is characterized by doing.

In the method for manufacturing a heat equalizing member for a fixing device according to this embodiment, the injected hydraulic fluid is less likely to spill from the pipe during and after the injection of the hydraulic fluid.

In the method for manufacturing a heat equalizing member for a fixing device according to an embodiment, when the other end of the pipe is sealed, a second plastic working is performed, and after the other end of the pipe is closed, the welding is performed. It is characterized by performing.

In the manufacturing method of the heat equalizing member for a fixing device according to this embodiment, the other end of the pipe is reduced in diameter by the first plastic working. The other end can be easily closed.

In the method of manufacturing a heat equalizing member for a fixing device according to one embodiment,
Of the outer peripheral surface of the pipe, the region for forming the heat-resistant release layer is only an inner region excluding outer end regions at both ends with respect to the longitudinal direction of the pipe,
When performing the welding, a heat dissipation tool is brought into contact with the outer end region on the other end side of the pipe, and heat is released from the outer end region through the heat dissipation tool.

In the method for manufacturing a heat equalizing member for a fixing device according to this embodiment, when performing the welding, a heat radiating tool is brought into contact with the outer end region on the other end side of the pipe so that the heat dissipation is performed from the outer end region. Dissipate heat through the tool. Therefore, it is possible to prevent the heat-resistant release layer from being deteriorated by the heat of the welding, or the internal pressure of the pipe from being increased to be ruptured or broken.

The heat equalizing member for the fixing device of the present invention is:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe by firing,
Through the other end of the pipe in which the heat-resistant release layer is formed, a working fluid is injected into the pipe from the outside,
Thereafter, the heat equalizing member for the fixing device is manufactured by welding and sealing the other end.

In the heat equalizing member for a fixing device according to the present invention, after the heat-resistant release layer is formed by firing on the outer peripheral surface of the pipe, the working liquid is injected into the pipe and the pipe is sealed. Therefore, when the heat-resistant release layer is formed by firing, the internal pressure of the pipe is not increased and is not ruptured or damaged. Therefore, the heat equalizing member for the fixing device is manufactured safely and with a high yield. Further, since the heat equalizing member for the fixing device has the heat-resistant release layer on the outermost periphery, it is difficult for dirt to adhere to the surface. Moreover, in this soaking | uniform-heating member, since the said pipe and the said heat-resistant release layer are closely_contact | adhered, soaking | uniform-heating performance is favorable and there is little heat capacity. In addition, since the number of members is smaller than that of a conventional example using a reinforcing cylinder (Japanese Patent Laid-Open No. 7-28351), this soaking member is manufactured at a low cost. In addition, the heat-resistant release layer has durability against heat at a target temperature suitable for fixing by a fixing device, and therefore the above-described leveling member is fixed to the fixing member for heating and / or pressing the conveyed sheet. The thermal member can maintain a stable contact over a long period of time. Therefore, the soaking effect is stabilized and sustained.

  In the heat-equalizing member for a fixing device according to an embodiment, the heat-resistant release layer is formed only in an inner region of the pipe excluding outer end regions on both ends in the longitudinal direction.

  In the heat-equalizing member for a fixing device according to this embodiment, the heat-resistant release layer is formed only in the inner region of the pipe excluding the outer end regions on both ends in the longitudinal direction. When stopping, the heat radiating tool is brought into contact with the outer end region, and heat can be radiated from the outer end region through the heat radiating tool. In such a case, it is possible to prevent the heat-resistant release layer from being deteriorated by the heat of the welding, or the internal pressure of the pipe from being increased to be ruptured or broken.

  In the heat equalizing member for a fixing device according to one embodiment, the material of the heat-resistant release layer is a fluororesin.

  In the heat-equalizing member for a fixing device of this embodiment, since the material of the heat-resistant release layer is a fluororesin, it is excellent in heat resistance and releasability and is inexpensive.

In another aspect, the heat equalizing member for a fixing device of the present invention is:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by powder-coating fluororesin on the outer peripheral surface of the internal region of the pipe and then firing the fluororesin.

In the heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, the heat equalizing member for a fixing device of the present invention is:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by applying a dispersion paint in which a fluororesin powder is dispersed in water on the outer peripheral surface of the inner region of the pipe and then firing the dispersion paint. And

In the heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, the heat equalizing member for a fixing device of the present invention is:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by covering the outer peripheral surface of the inner region of the pipe with a tube made of a fluororesin and then firing the tube.

In the heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, the heat equalizing member for a fixing device of the present invention is:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by immersing the outer peripheral surface of the inner region of the pipe in a molten fluororesin, attaching the fluororesin around the outer peripheral surface, and attaching the fluororesin attached around the outer peripheral surface. The film thickness is made constant by using a film thickness regulating blade, and then the fluororesin is baked.

In the heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

In another aspect, the heat equalizing member for a fixing device of the present invention is:
Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by applying a molten fluororesin to the outer peripheral surface of the internal region of the pipe using a roll coater and then firing the fluororesin.

In the heat equalizing member for a fixing device of this aspect, the heat-resistant release layer is easily formed.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 shows a cross-sectional structure of a fixing device including a heat equalizing member according to an embodiment of the present invention. This fixing device is used to fix a toner image on a sheet in an electrophotographic image forming apparatus (such as a copying machine or a printer).

  As shown in FIG. 1, this fixing device generally includes a fixing roller 2, a heating belt 1 around which the fixing roller 2 is wound, a pressure roller 5, a soaking member 8, an exciting coil 3, and a magnetic member. The body core 4, the temperature sensor 50, the control circuit 60, and the high frequency inverter 70 are provided. Reference numeral 90 denotes a sheet as a sheet.

  The fixing roller 2, the pressure roller 5, and the soaking member 8 are cylindrical members that extend perpendicular to the paper surface of FIG. 1, are arranged in parallel to each other, and both ends are rotatable to bearing members (not shown). It is supported by.

  In this example, the fixing roller 2 includes a metal core 2a made of stainless steel and a silicone sponge layer 2b having a thickness of 10 mm that covers the outer peripheral surface of the metal core 2a. The diameter of the fixing roller 2 as a whole is set to 40 mm.

  Although not shown in detail, the heating belt 1 is composed of a heat generating layer made of a 40 μm thick Ni belt that generates eddy current by electromagnetic induction and a 200 μm thick silicone rubber layer formed on the surface thereof. It is composed of a heat-resistant elastic layer and a heat-resistant release layer made of PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) having a thickness of 30 μm which is coated on the surface and prevents adhesion of toner or the like.

  The pressure roller 5 is composed of a core metal 5a made of STKM (carbon steel pipe for mechanical structure) having a diameter of 35 mm, a heat-resistant elastic layer 5b made of two layers of Si rubber and Si sponge, and PFA coated on the surface thereof. And a heat-resistant release layer 5c. The pressure roller 5 is urged toward the fixing roller 2 with a pressing force of about 500 N by a pressure mechanism (not shown) using a spring or the like. As a result, the pressure roller 5 forms a nip portion for fixing having a dimension of about 12 mm in the conveyance direction of the paper 90 with the heating belt 1 surrounding the fixing roller 2.

  As shown in FIG. 2 (d), the soaking member 8 is generally formed in close contact with a cylindrical copper pipe 10 in which water 13 as a working fluid is sealed, and the outer peripheral surface of the copper pipe 10. It is comprised with the heat-resistant release layer 12 which consists of a PFA tube. The heat equalizing member 8 is urged toward the pressure roller 5 by a pressure mechanism (not shown) using a spring or the like.

  The pressure roller 5 is rotationally driven at a predetermined peripheral speed in a counterclockwise direction indicated by an arrow b in FIG. 1 by a drive mechanism (not shown). The heating belt 1 is rotated along with the fixing roller 2 by the rotation of the pressure roller 5 by the frictional force with the pressure roller 5 at the nip portion, and rotates in the clockwise direction indicated by an arrow a in FIG. The heat equalizing member 8 is also rotated in the clockwise direction indicated by an arrow c in FIG. 1 following the rotation of the pressure roller 5 by the frictional force with the pressure roller 5.

  The exciting coil 3 is provided to generate a magnetic flux upon receiving power supply from the high frequency inverter 70. The exciting coil 3 is formed by winding a wire bundle in an elliptical shape a plurality of times (about 10 times in this example) along the longitudinal direction of the fixing roller 2. In FIG. 1, 3a indicates the forward path portion of the conductor bundle, and 3b indicates the return path portion of the conductor bundle. One conductor bundle has a diameter formed by bundling 114 strands (copper wires having a diameter of about 0.18 mm to 0.20 mm, which are insulated and coated with enamel) in order to increase current-carrying efficiency. It is a known stranded wire (Litz wire) of about several mm.

  The magnetic core 4 includes a substantially chevron-shaped main core 4a disposed along the outer periphery of the heating belt 1, and a central core 4b provided so as to protrude from the center toward the heating belt 1 in the circumferential direction of the main core 4a. And hem cores 4c and 4d provided to protrude from both end portions toward the heating belt 1 in the circumferential direction of the main core 4a. The central core 4b enters the gap between the forward path portion 3a and the return path portion 3b of the exciting coil 3. The bottom cores 4c and 4d cover the outer edges of the forward path portion 3a and the return path portion 3b of the exciting coil 3. Each part of the magnetic core 4 is made of MnZn-based ferrite. As a result, the magnetic flux generated by the exciting coil 3 passes from the central core 4b to the left side of the main core 4a in FIG. 1, passes through the bottom core 4c and the heat generating layer of the heating belt 1, and returns to the central core 4b. Form. In contrast, a magnetic circuit is formed from the central core 4b to the main core 4a in FIG. 1 through the right side portion, the bottom core 4d, and the heat generating layer of the heating belt 1 and returning to the central core 4b. As described above, when the magnetic flux passes through the heat generating layer of the heating belt 1 and the magnetic flux alternates, an eddy current is generated in the heat generating layer to generate heat.

  The temperature sensor 50 is, for example, a non-contact infrared temperature sensor, and is disposed so as to face and approach the outer peripheral surface of the heating belt 1. Note that a contact thermistor may be used for the temperature sensor 50. A detection signal from the temperature sensor 50 is input to the control circuit 60. The control circuit 60 controls the high frequency inverter 70 based on the detection signal of the temperature sensor 50, and the power from the high frequency inverter 70 to the exciting coil 3 so that the surface temperature of the heating belt 1 becomes a target temperature suitable for fixing. Increase or decrease the supply. As the temperature sensor 50, in addition to the infrared temperature sensor, a thermostat or the like for ensuring safety may be used.

During the fixing operation, as described above, the pressure roller 5 is rotationally driven counterclockwise in FIG. 1, and the fixing roller 2 and the heating belt 1 are rotated clockwise in FIG. At the same time, the heat generation layer of the heating belt 1 generates heat by electromagnetic induction due to the magnetic flux generated by the exciting coil 3, and the surface temperature of the heating belt 1 is automatically controlled to reach the target temperature (about 180 ° C. in this example). In this state, a sheet 90 as a sheet having an unfixed toner image 91 formed on one side is fed from the right side in FIG. 1 to a nip formed by the heating belt 1 and the pressure roller 5 by a conveyance mechanism (not shown) . It is. The sheet 90 fed to the nip portion is heated by the heating belt 1 when passing through the nip portion. As a result, the unfixed toner image 91 is fixed on the paper 90. The sheet 90 passing through the nip portion is discharged leftward in FIG. Note that an OHP sheet or the like may be used instead of the sheet 90.

  When small-size paper is continuously passed, the heat of the heating belt 1 in the area where the paper does not contact in the width direction (non-paper passing area) is not deprived. The heat stays in the non-sheet passing area of the paper and tries to increase the temperature locally. Here, the heat equalizing member 8 removes heat from the non-sheet passing region of the heating belt 1 and the pressure roller 5 and uses the latent heat of the sealed working fluid to equalize the heat equalizing member 8 in the longitudinal direction. To do. Thereby, the temperature distribution difference in the width direction of the heating belt 1 (longitudinal direction of the pressure roller 5) is reduced, and soaking is achieved.

  If the heat equalizing member 8 is not provided, when the large size paper is passed after passing the small size paper, the toner is overmelted in the non-paper passing area, and the high temperature offset is caused. May occur, or uneven gloss may occur. If the temperature further rises, melting of parts around the fixing device also occurs.

  As described with respect to the conventional example, when the heat pipe is directly pressed against the pressure roller, toner or paper powder slightly offset at the time of image fixing adheres to the surface of the heat pipe as dirt. On the other hand, in this embodiment, since the heat-resistant release layer 12 made of PFA is provided on the outermost periphery of the soaking member 8, dirt is hardly attached to the surface.

  Moreover, in this heat equalization member 8, since the copper pipe 10 and the heat-resistant release layer 12 are closely_contact | adhered, heat equalization performance is favorable and there is little heat capacity. Further, since the number of members is smaller than that of the conventional example (Japanese Patent Laid-Open No. 7-28351) using the reinforcing cylinder, the soaking member 8 is manufactured at a low cost. Further, since the heat-resistant release layer 12 has durability against heat at a target temperature suitable for fixing (in this example, about 180 ° C.), the heat equalizing member 8 is stable over a long period of time against the pressure roller 5. And keep in touch. Therefore, the soaking effect is stabilized and sustained.

  2A to 2D illustrate the manufacturing process of the soaking member 8.

  First, as shown in FIG. 2A, an elongated copper pipe 10 is prepared in which the left end 10e as one end is sealed and the right end 10f as the other end is opened. In this example, the copper pipe 10 is a single piece having a diameter of 21 mm and a thickness of 0.8 mm.

  A primer 11 is applied to the outer peripheral surface 10a of the copper pipe 10 to enhance the adhesive force of the heat-resistant release layer described below. In this example, the material of the primer 11 is a fluororesin component (polytetrafluoroethylene) having adhesiveness between a binder component (acrylic, polyamideimide, polyimide, polyphenylene sulfide, polyethersulfone, etc.) having adhesiveness with a metal and a fluororesin. Fluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, a mixture of tetrafluoroethylene / hexafluoropropylene copolymer and the like) are generally used for adhesion of metal and fluororesin. It is what has been.

  Next, as shown in FIG. 2B, the heat-resistant release layer 12 made of PFA is formed in close contact with the outer peripheral surface 10a of the copper pipe 10 (more precisely, the outer peripheral surface of the primer 11). In this example, as a method for forming the heat-resistant release layer 12, a copper pipe 10 is covered with a PFA tube and fired at about 400 ° C.

  Here, the region where the heat-resistant release layer 12 is formed is only the inner region A of the copper pipe 10 excluding the outer end regions B and C on both ends in the longitudinal direction. The internal area A substantially corresponds to an area through which a maximum size sheet scheduled by the fixing device passes.

  The region where the primer 11 is applied is set with a margin so as to be slightly wider than the inner region A in the longitudinal direction of the copper pipe 10.

  Next, as shown in FIG. 2C, the first plastic working is crushed to reduce the diameter of the right end 10f of the pipe 10 (the right end 10f is not yet closed at this stage). Subsequently, water 13 as a working fluid is injected into the pipe 10 from the outside through the right end 10f having a reduced diameter. Here, since the diameter of the right end 10f of the pipe 10 is reduced, the already injected water 13 is unlikely to spill from the pipe 10 during and after the injection of the water 13.

  Next, as shown in FIG. 2 (d), a vacuum pump (not shown) is connected to the right end 10f of the pipe 10 to evacuate the inside of the pipe 10, and in this vacuum state, crushing as a second plastic working is performed. The right end 10f of the pipe 10 is closed (temporary sealing).

  Subsequently, after removing the vacuum pump, brazing as welding is performed to seal the right end 10f of the pipe 10 (main sealing).

  Here, when sealing the right end 10f of the pipe 10 by welding, if no contrivance is given, the temperature of the pipe 10 rises due to the heat of welding, and the heat-resistant release layer 12 is deteriorated or damaged. There is a fear. Therefore, in this embodiment, as shown in FIG. 3, when welding is performed, heat is radiated using the heat radiation tool 20.

  Specifically, the heat radiating tool 20 sandwiches the outer end region C on the right end 10f side of the pipe 10 (more precisely, the portion 10c of the outer end region C that is left with the original outer diameter) from both sides. A pair of fixing tools 15A, 15B for fixing at one end, a pair of cooling heat pipes 16A, 16B each having one end penetrating the fixing tools 15A, 15B, and the other end side of the cooling heat pipes 16A, 16B A pair of heat sinks 17A and 17B attached to the.

  The fixtures 15A and 15B and the heat sinks 17A and 17B are made of members having good thermal conductivity such as aluminum and copper. A curved surface having the same curvature as the original outer diameter of the pipe 10 is formed on the surface of the fixtures 15A and 15B on the pipe 10 side so as to increase the contact area with the pipe 10. The heat sinks 17A and 17B are provided with a large number of fins so as to increase the surface area. The heat pipes 16A and 16B for cooling are made of cylindrical copper pipes filled with water as a working fluid.

  When welding is performed, a portion 10c of the outer end region C on the right end 10f side of the pipe 10 that is left with its original outer diameter is sandwiched and fixed from both sides by the fixtures 15A and 15B. The heat sinks 17A and 17B are cooled by the cooling fan 18. In this state, as shown in FIG. 2D, the right end 10f of the pipe 10 is sealed by welding (brazing). The heat of welding is transmitted from the right end 10f of the pipe 10 to the portion 10c remaining with its original outer diameter, the fixtures 15A and 15B, the cooling heat pipes 16A and 16B, and the heat sinks 17A and 17B. Then, with the help of the cooling fan 18, heat is efficiently radiated from the heat sinks 17A and 17B into the atmosphere. In this case, the inner region A of the pipe 10 is suppressed to a temperature of about 260 ° C. or less that the heat resistant release layer 12 can withstand. Accordingly, it is possible to prevent the heat-resistant release layer 12 of the heat equalizing member 8 from being deteriorated by the heat of welding, or the internal pressure of the pipe 10 from being increased to be ruptured or damaged.

  In addition, in this example, although air cooling is performed using the heat radiating tool 20, it is not restricted to this. As a means for radiating the heat of welding, for example, pipes for circulating refrigerant may be provided through the fixtures 15A and 15B, and water cooling or oil cooling with water or oil may be performed.

  In the above example, as a method for forming the heat-resistant release layer 12, the outer periphery of the copper pipe 10 is covered with a PFA tube and fired. Of course, this is not a limitation.

  For example, the heat resistant release layer 12 may be formed by powder electrostatic coating of fluororesin on the outer peripheral surface of the inner region A of the pipe 10 and then firing the fluororesin.

  Alternatively, the heat-resistant release layer 12 may be formed by applying a dispersion paint in which a fluororesin powder is dispersed in water on the outer peripheral surface of the inner region A of the pipe 10 and then firing the dispersion paint. good.

  Further, the outer peripheral surface of the inner region A of the pipe 10 is immersed in a molten fluororesin so that the fluororesin is attached around the outer peripheral surface, and the film thickness of the fluororesin attached around the outer peripheral surface is determined by a film thickness regulating blade. Then, the heat-resistant release layer 12 may be formed by baking the fluororesin.

  Alternatively, the heat-resistant release layer 12 may be formed by applying a molten fluororesin to the outer peripheral surface of the inner region A of the pipe 10 using a roll coater and then firing the fluororesin.

  In the above example, the material of the pipe 10 is made of copper, but aluminum or the like may be used. The material of the pipe 10 is desirably a metal material having good thermal conductivity and a certain degree of rigidity.

  In the above example, the material of the heat-resistant release layer 12 is PFA. However, the material is not limited to this. As a material for the heat-resistant release layer 12, in addition to PFA, PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PFEP (perfluoroethylene / hexafluoropropylene copolymer), etc. The fluororesin may be used. Since these are fluororesins, they are excellent in heat resistance and releasability and are inexpensive. Therefore, it is preferably used.

It is a figure which shows the cross-sectional structure of the fixing device provided with the heat equalization member of one Embodiment of this invention. It is process drawing which shows the manufacturing process of the said heat equalization member. It is a figure which shows the aspect which air-cools using a thermal radiation tool.

DESCRIPTION OF SYMBOLS 1 Heating belt 2 Fixing roller 3 Excitation coil 4 Magnetic body core 5 Pressure roller 8 Heat equalizing member 10 Copper pipe 12 Heat-resistant release layer

Claims (20)

Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe by firing ,
Through the other end of the pipe in which the heat-resistant release layer is formed , a working fluid is injected into the pipe from the outside ,
Then, the manufacturing method of the soaking | uniform-heating member for fixing devices which welds and seals the said other end. In the manufacturing method of the soaking | uniform-heating member for fixing devices of Claim 1,
After forming the heat-resistant release layer and before injecting the hydraulic fluid, a first plastic working is performed to reduce the diameter of the other end of the pipe. . In the manufacturing method of the soaking | uniform-heating member for fixing devices of Claim 2,
When the other end of the pipe is sealed, a second plastic working is performed, the second end of the pipe is closed, and then the welding is performed. . In the manufacturing method of the soaking | uniform-heating member for fixing devices of Claim 1,
Of the outer peripheral surface of the pipe, the region for forming the heat-resistant release layer is only an inner region excluding outer end regions at both ends with respect to the longitudinal direction of the pipe,
A heat equalizing member for a fixing device, wherein when performing the welding, a heat radiating tool is brought into contact with the outer end region on the other end side of the pipe, and heat is radiated from the outer end region through the heat radiating tool. Manufacturing method. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by performing powder electrostatic coating of fluororesin on the outer peripheral surface of the internal region of the pipe and then baking the fluororesin. Production method. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by applying a dispersion paint in which a fluororesin powder is dispersed in water on the outer peripheral surface of the inner region of the pipe, and then baking the dispersion paint. A method for producing a soaking member for a fixing device. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by covering the outer peripheral surface of the inner region of the pipe with a tube made of a fluororesin and then firing the tube. . Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by immersing the outer peripheral surface of the inner region of the pipe in a molten fluororesin, causing the fluororesin to adhere around the outer peripheral surface, and the fluorine adhering around the outer peripheral surface. A method for producing a heat-uniforming member for a fixing device, wherein the film thickness of the resin is made constant using a film thickness regulating blade, and then the fluororesin is baked. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
Manufacturing a heat equalizing member for a fixing device in which a working fluid is injected into the pipe from the outside through the other end of the pipe in which the heat-resistant release layer is formed, and then the other end is sealed by welding. A method,
The heat-resistant release layer is formed by applying a molten fluororesin to the outer peripheral surface of the inner region of the pipe using a roll coater and then firing the fluororesin. Manufacturing method of thermal member. In the manufacturing method of the soaking | uniform-heating member for fixing devices in any one of Claim 5 thru | or 9,
After forming the heat-resistant release layer and before injecting the hydraulic fluid, a first plastic working is performed to reduce the diameter of the other end of the pipe. . In the manufacturing method of the soaking | uniform-heating member for fixing devices of Claim 10,
When the other end of the pipe is sealed, a second plastic working is performed, the second end of the pipe is closed, and then the welding is performed. . In the manufacturing method of the soaking | uniform-heating member for fixing devices in any one of Claim 5 thru | or 9,
Of the outer peripheral surface of the pipe, the region for forming the heat-resistant release layer is only an inner region excluding outer end regions at both ends with respect to the longitudinal direction of the pipe,
A heat equalizing member for a fixing device, wherein when performing the welding, a heat radiating tool is brought into contact with the outer end region on the other end side of the pipe, and heat is radiated from the outer end region through the heat radiating tool. Manufacturing method. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe by firing,
Through the other end of the pipe in which the heat-resistant release layer is formed, a working fluid is injected into the pipe from the outside,
Then, a heat equalizing member for a fixing device manufactured by welding and sealing the other end. The soaking member for a fixing device according to claim 13 ,
The heat-resisting release layer is formed only in an inner region of the pipe excluding outer end regions on both ends in the longitudinal direction. The heat equalizing member for a fixing device according to claim 13 or 14 ,
A heat-uniforming member for a fixing device, wherein the heat-resistant release layer is made of a fluororesin. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resisting release layer is formed by subjecting the outer peripheral surface of the inner region of the pipe to electrostatic powder coating of fluororesin and then baking the fluororesin. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by applying a dispersion paint in which a fluororesin powder is dispersed in water on the outer peripheral surface of the inner region of the pipe and then firing the dispersion paint. A soaking member for a fixing device. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
A heat equalizing member for a fixing device, wherein the heat-resistant release layer is formed by covering the outer peripheral surface of the inner region of the pipe with a tube made of a fluororesin and then firing the tube. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by immersing the outer peripheral surface of the inner region of the pipe in a molten fluororesin, attaching the fluororesin around the outer peripheral surface, and attaching the fluororesin attached around the outer peripheral surface. A heat equalizing member for a fixing device, which is formed by making the film thickness constant by using a film thickness regulating blade and then baking the fluororesin. Prepare an elongated cylindrical pipe made of a metal material, sealed at one end and open at the other end,
Forming the heat-resistant release layer in close contact with the outer peripheral surface of the pipe,
For a fixing device manufactured by injecting a working fluid from outside into the pipe through the other end of the pipe in which the heat-resistant release layer is formed, and then sealing the other end by welding. Soaking member,
The heat-resistant release layer is formed by applying a molten fluororesin to the outer peripheral surface of the inner region of the pipe using a roll coater and then firing the fluororesin. Thermal member.

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