JP6361158B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus, and more particularly to image fixing and drying of a sheet member in an electrophotographic image forming apparatus or an ink jet image forming apparatus.

  In the technical field of image forming apparatuses, a process for fixing the formed image is often performed after the image is formed on the sheet member by various methods such as an electrophotographic method and an ink jet method. At this time, the sheet member is preferably pressed by a roller and heated by some means. When the melted toner or ink is entangled with the fibers of the sheet member and the sheet member is further cooled, the formed image can be firmly fixed on the sheet member.

  Many of the conventional fixing devices are provided with a halogen lamp inside the roller, and when the halogen lamp emits light, the roller is heated by light emitted from the halogen lamp, and a temperature sensor provided on the roller surface indicates that the target temperature has been reached. After checking, the toner and ink are melted by the heat and pressure of the roller by passing through the sheet coated with toner and ink, entangled with the fibers of the sheet member, and the melted toner and ink are solidified by cooling. It was possible to fix the sheet member.

  However, the fixing method using the conventional halogen lamp requires a long time to reach the target temperature (rise time), and when using the printer, the user is dissatisfied with the printer rise time and the power consumption per hour (TEC). Value).

  Today, inkjet is also required to increase the speed. However, if the ink is so thirsty that it contains a lot of moisture, the bottom image will appear when the printed image is smeared on the back or when a large amount of printed material is loaded. There arises a problem such as sticking to the back of the image. Therefore, a drying device for drying ink is required today.

  In contrast to such a method of heating using a halogen lamp, Patent Documents 1 and 2 disclose a method of heating using the principle of high-frequency dielectric. Patent Documents 1 and 2 are prior art examples of a fixing device that performs high-frequency dielectric heating. In the fixing device disclosed in Patent Document 1, heating is performed by applying high-frequency power to the electrodes, unlike the conventional heating of rollers and belts by light emission of a halogen lamp.

  Generally speaking, high frequency dielectric heating has the advantage that it can be rapidly and uniformly heated and dried. However, Patent Document 1 and Patent Document 2 attempt to directly heat the toner and ink on the sheet member by applying high-frequency power to the rod-shaped electrode. However, it has been experimentally found that the toner may not self-heat even when high frequency power is applied. In addition, even when the ink is dried, there is a problem that the drying efficiency is lowered due to factors such as the type of ink, the amount of ink, the film thickness, and the area.

  SUMMARY OF THE INVENTION An object of the present invention is to enable rapid and uniform heating and drying in a fixing device of an image forming apparatus, while overcoming the problems of a system in which a heating target is directly heated by high-frequency dielectric.

In order to achieve the above object, one aspect of the present invention provides a high frequency dielectric control circuit, a high frequency dielectric power supply circuit controlled by the high frequency dielectric control circuit, and a first conductive rotation to which the high frequency dielectric power supply circuit is connected. Body, a high dielectric member covering the first conductive rotator, and a second conductive rotation provided at a position facing the first conductive rotator and connected to the high frequency dielectric power supply circuit. The high-frequency dielectric power supply circuit applies a high-frequency AC electric field voltage to the first and second conductive rotating bodies, and the first conductive rotating body includes the first conductive rotating body. provided below the second electrically conductive rotating object, the high dielectric member covering the first electrically conductive rotating object is a gel-like, is contained in the low dielectric member through electromagnetic waves, the high-frequency dielectric power supply circuit , By the return current from the second conductive rotor, Voltage of the field, and wherein the monitoring current, or frequency.

  According to the present invention, rapid and uniform heating and drying can be performed in a fixing device of an image forming apparatus.

It is a conceptual diagram for demonstrating the principle of the high frequency dielectric utilized by embodiment. 1 is a diagram illustrating a configuration of a fixing device according to a first embodiment of the present invention. It is a figure which shows the structure of the fixing device of 2nd Embodiment by this invention. It is a figure which shows the structure of the fixing device of 3rd Embodiment by this invention. It is a figure which shows the structure of the fixing device of 4th Embodiment by this invention. It is a figure which shows the structure of the heat-generating layer made into the multilayer which can be used in the said embodiment.

  Embodiments according to the present invention to be described below use on-demand dielectric heating to compress the rise time of the image forming apparatus and enable on-demand fixing that instantly starts up the printer. In addition, by compressing the rise time of the image forming apparatus, it is possible to eliminate user dissatisfaction and reduce power consumption (TEC value) per hour. Note that when using high-frequency dielectric heating, the toner or ink originally intended to be heated is not directly heated, but indirectly heated by the configuration described later. The principle of high frequency dielectric heating will be briefly described below.

FIG. 1 is a conceptual diagram for explaining the principle of high-frequency dielectric used in this embodiment.
High-frequency dielectric heating is a heating method used for a dielectric that is a substance having a dielectric property superior to conductivity. The dielectric contains few free electrons but instead contains many dipoles with positive and negative equivalent charges on both sides of the molecule (Fig. 1 (A)). , (B)).

  As the direction of the electric lines of force applied from the outside changes, the dipole tries to change the axial direction of the array without changing the average position (FIG. 1C). However, if the vibration of the dipole cannot catch up with the change in polarity of the electric field, the difference becomes a dielectric loss, and heat is generated due to the dielectric loss. Therefore, the ease of vibration of the dielectric affects the heating efficiency.

  In addition, dielectric heating is possible not only with high frequency but also with microwaves. In this specification, the term “high-frequency dielectric” includes dielectric by microwave.

The advantage of high-frequency dielectric heating is that the dielectric to be heated can be heated uniformly at high speed in the order of several seconds. In an external heating method such as a halogen heater, the heat transfer to the center is due to the heat conduction of the object to be heated. For this reason, even if the outside temperature rises, the central portion does not readily rise in temperature, and it takes a long time to raise the temperature inside. On the other hand, since the heating target itself generates heat, it does not require heat conduction time and can be heated uniformly in a short time.
In the present embodiment, such high-frequency dielectric heating is indirectly heated instead of directly heating the ink by the configuration described below.

<First Embodiment>
Heat and pressure are required to melt the toner and dry the ink in order to fix the toner or ink on the sheet member. Therefore, as shown in FIG. 2, the present embodiment includes a high dielectric member 106, a conductive roller 105, a high frequency dielectric power supply circuit 101, and a conductive counter roller 103 as heat sources. In addition, a sheet member conveying roller pair 120 for conveying the sheet member 121 and a cleaning mechanism 122 for adjusting excess toner are also provided. Since the basic principle of heat generation has been described above, it will be omitted here and a specific operation will be described.

  First, in a system in which the fixing device is mounted, a printing start signal is transmitted from the system to the high frequency dielectric control circuit 100 before the conveyance of the sheet member 121 is started. The high-frequency dielectric control circuit 100 turns on the high-frequency dielectric power supply circuit 101, controls the AC voltage and frequency of the high-frequency power supply so as to have a preset target value, changes the rotating electrode, and applies it to the conductive roller 105. .

  In the present fixing device, it is necessary to cause the fixing device to generate heat in order to apply heat to the sheet member 121 coated with toner or ink. Therefore, in the present embodiment, the high-frequency dielectric control circuit 100 and the high-frequency dielectric power supply circuit 101 are a high-dielectric body located between the conductive roller 105 and the conductive counter roller 103 connected via the rotating electrodes 102 and 104. An AC electric field is applied to the member 106. As a result, the molecular dipole in the high dielectric member 106 covering the periphery of the conductive roller 105 is vibrated at a high speed by applying an AC electric field at a high frequency, causing collision, vibration, friction, etc. to generate heat.

  In this AC power supply circuit, the return current from the counter electrode and the temperature sensor provided on the surface of the high dielectric member 106 are constantly monitored for the voltage, current and frequency of the AC electric field to prevent abnormal temperatures and A function is also provided that enables maintenance and management of the heat generation temperature of the high-dielectric material with respect to the temperature, and further makes it possible to control temperature fluctuations due to differences in material and thickness when the sheet member passes.

  Next, when the fixing device reaches a target temperature, the high-frequency dielectric control circuit 100 transmits a signal indicating that preparation for fixing of the sheet member 121 is complete to the system. Upon receiving this signal, the system starts conveying the sheet member 121 coated with the toner or ink created by the image forming function. The sheet member 121 is conveyed to the fixing device by the action of the sheet member conveying roller pair 120. The toner on the sheet member 121 is melted by heat generated by the high dielectric member 106 and pressure applied by the conductive facing roller 103 and the conductive roller 105. Further, the ink can be dried and fixed on the sheet member 121.

  After fixing, the sheet member 121 is again discharged to the sheet discharge device of the system by the sheet member conveying roller pair 120, and a series of fixing operations is completed. At this time, in the present fixing device, the sensor confirms that the sheet member 121 has exited the fixing device. The high frequency dielectric control circuit 100 transmits a stop signal to the high frequency dielectric power supply circuit 101 to stop the high frequency power supply output.

  At this time, when the sheet member is continuously conveyed, the high-frequency power output is continued as it is to prevent the heat generation temperature of the fixing device from decreasing.

  Further, although described as the conductive roller 105 in this embodiment, the conductive roller referred to here is a rigid metal (for example, iron, copper, aluminum, etc.), a conductive resin, or a resin surface. The metal coated member is shown. Further, the material of the high dielectric member here is preferably a substance having a high relative dielectric constant.

  According to the present embodiment described above, rapid and uniform heating and drying can be performed in the fixing device for the reasons described in the merits of the high-frequency dielectric heating, so that the needs for on-demand printing can be met. In addition, power consumption per hour can be suppressed. On the other hand, unlike the configuration in which the ink or toner on the sheet member is directly heated, the high dielectric member 106 in which the gel-like member is encapsulated is heated by instantaneously raising the temperature. For example, the temperature rise efficiency is not affected by the type and amount of ink, film pressure, area, and the like. Although it is difficult to perform high-frequency dielectric heating on the toner, according to the configuration of the present embodiment, high-frequency dielectric heating can be applied to a fixing device that heats the toner.

  In the fixing device shown in FIG. 2, in addition to the heat generating structure (high dielectric member 106 + conductive roller 105 + conductive counter roller 103), an interlock function is provided for opening and closing the shield cover 108. Since this embodiment uses high frequency dielectric heating, electromagnetic wave leakage occurs, and there is a concern about the influence on the human body or malfunction of the system itself. Therefore, the entire fixing device is covered with a shield cover 108 made of a conductive member except for the entrance / exit of the sheet member 121 and connected to the FG of the high frequency dielectric power supply circuit 101 to prevent leakage of electromagnetic waves as much as possible.

  In order to prevent leakage of electromagnetic waves, a system equipped with this fixing device detects the opening and closing of these covers with a sensor when opening the shield cover 108 or system housing cover during maintenance, thus preventing leakage of electromagnetic waves. Therefore, it has a function of turning off the output of the high frequency dielectric power supply circuit 101 in software and hardware (such as turning off the control power supply of the high frequency dielectric power supply circuit).

In addition, the high frequency mentioned here is 10kHz in the ISM band (Industry-Science-Medical) of the frequency band designated for using the radio wave as an energy source for industry, science, and medicine by the International Telecommunications Union (ITU). The range of 30 GHz. In general, it is preferable to use frequencies of 13.56 MHz, 27.12 MHz, 40.68 MHz, 915 MHz, 2.45 GHz, 5.8 GHz, and 24.125 GHz that are generally used for industrial use.
According to the configuration described above, the influence of electromagnetic waves can be avoided.

<Second Embodiment>
A modification (second embodiment) of the above embodiment will be described with reference to FIG.
Usually, in order to increase the calorific value and to prevent thermal deformation, the dielectric includes the use of a liquid or gel-like material centered on water that exhibits a high relative dielectric constant and a high dielectric loss tangent value. Conceivable. However, when these materials are used, they generate heat and evaporate.

  Therefore, these dielectrics are covered with a low dielectric member 107 in order to prevent evaporation. For example, as shown in FIG. 3, a low dielectric member 107 made of a material that transmits electromagnetic waves generated by an alternating electric field such as silicon rubber or Teflon (registered trademark) is used. For example, silicon rubber or Teflon is processed into a cylindrical bag shape, a high dielectric member 106 is injected therein, and is bonded and fixed to the conductive roller 105 in a cylindrical shape.

  Also, silicon rubber, other rubber members, or Teflon is foamed into a cylindrical shape, and liquid or gel-like high dielectric member 106 is injected or impregnated into the foamed hole, and liquid leakage from both ends of the roller is caused by post-processing. Such a method may be employed that welding is performed so as not to occur, and then the adhesive roller 105 is bonded and fixed.

  As described above, by using a rubber member or a Teflon member and injecting a high dielectric member 106 in the form of a liquid or a gel, it is deformed by pressure at the time of contact with the conductive facing roller 103 provided at the facing position, and the nip A width can be secured, which is effective when fixing the sheet member 121 coated with toner or ink. In addition, transpiration of the high dielectric can be prevented.

<Third Embodiment>
With reference to FIG. 4, still another modified example (third embodiment) of the above embodiment will be described.
The first or second embodiment has a limit in securing the nip width. Since the nip width is small, the passing width of the AC electric field is small, and the volume of the high dielectric material that generates heat is small, so that it is difficult to cope with high speed. Therefore, in the present embodiment, the area and volume of contact between the high dielectric and the counter electrode are increased by forming the high dielectric and the counter electrode in a belt shape. For this reason, since the heat generation area of the high dielectric can be secured, it is possible to cope with high speed.

A specific configuration and operation will be described below.
In order to fix the toner on the sheet member to which the toner or ink is applied, it is necessary to melt the toner. Also, heat and pressure are required to dry the ink. As shown in FIG. 4, the present embodiment includes conductive rollers 103a and 105a, a high dielectric belt 106a, a high frequency power supply circuit 101, and a conductive counter belt 103b as heat sources. Since the basic principle of heat generation has been described above, it will be omitted here and a specific operation will be described.

  First, in a system in which the fixing device is mounted, a printing start signal is transmitted from the system to the high frequency dielectric control circuit 100 before the conveyance of the sheet member 121 is started. The high-frequency dielectric control circuit 100 turns on the high-frequency dielectric power supply circuit 101, controls the AC voltage and frequency of the high-frequency power supply so as to have a preset target value, and changes the rotating electrode to the conductive rollers 103a and 105a. Apply.

  Here, the fixing device needs to heat the fixing device in order to apply heat to the sheet member 121 coated with toner or ink. Therefore, the high-frequency dielectric control circuit 100 and the high-frequency dielectric power supply circuit 101 are connected to the conductive roller 105a connected by changing the rotating electrode and the high dielectric belt 106a attached so as to contact the roller and the conductive counter belt 103b. Apply an alternating electric field. As a result, a molecular dipole in a high dielectric covering the periphery of the conductive roller 105a is vibrated at a high speed by applying an AC electric field at a high frequency, and heat is generated by causing collision, vibration, friction, and the like.

  Furthermore, in the present embodiment, as shown in FIG. 4, a plurality of fixed electrodes 109 are provided inside the high dielectric belt 106a. For this reason, when an AC electric field is applied by the high frequency dielectric power supply circuit 101, rapid and uniform heat generation occurs.

  In this AC power supply circuit, the return current from the conductive roller 103a in contact with the conductive opposing belt 103b and the temperature sensor provided on the surface of the high dielectric belt 106a are used to measure the voltage, current, The frequency is constantly monitored to prevent abnormal temperatures, to maintain the heat generation temperature of the high dielectric relative to the target temperature, and to control the temperature fluctuation due to the difference in material and thickness when the sheet member 121 passes. A function is also provided.

  Next, when the fixing device reaches a target temperature, the high-frequency dielectric control circuit 100 transmits a signal indicating that preparation for fixing of the sheet member 121 is complete to the system. Upon receiving this signal, the system starts transporting the sheet member 121 coated with the toner and ink produced by the image forming function, and transports the sheet member 121 to the main fixing device through the pair of sheet member transport rollers 120. The toner can be melted by heat generation and pressure applied by the conductive opposing belt 103b and the high dielectric belt 106a. Further, the ink can be dried and fixed on the sheet member 121.

  After fixing, the sheet member 121 is again discharged to the sheet discharge device of the system by the sheet member conveying roller pair 120, and a series of fixing operations is completed. At this time, the fixing device confirms with the sensor that the sheet member 121 has left the fixing device. Then, a stop signal is transmitted from the high frequency dielectric control circuit 100 to the high frequency dielectric power supply circuit 101 to stop the high frequency power supply output. At this time, when the sheet member 121 is continuously conveyed, the high-frequency power output is continued as it is to prevent the heat generation temperature of the fixing device from decreasing.

  According to this embodiment described above, a further nip width can be obtained than in the above-described embodiments. Therefore, it is possible to increase the amount of heat per unit time applied to the sheet member, and further increase the speed.

  In the first and third embodiments, the roller (conductive counter roller 103 in FIG. 2) and the belt (conductive counter belt 103b in FIG. 4) at the position opposite to the high dielectric member 106 are innocent. In the case of using metal, the toner or ink applied to the sheet member 121 may partially stick to the metal surface due to the pressure of the high dielectric roller or belt, causing image peeling on the sheet member surface.

  Therefore, it is preferable to perform a surface treatment of a releasable material (for example, silicon or Teflon) that allows electromagnetic waves to pass through a member that contacts the toner or ink application surface of the sheet member 121. By doing so, the strength of the adhesion force of the toner and the ink agent to the sheet member 121 is greater than the adhesion force of the toner and the ink to the member that contacts the toner and the ink application surface, and the separation of the toner and the ink can be prevented. . FIG. 4 shows an example in which such a releasable material 107a is surface-treated to a high dielectric belt 106a. Note that the technical idea of processing the surface of the releasable material 107a can be applied to the high dielectric member 106 and the low dielectric member 107 in the first and second embodiments.

<Fourth Embodiment>
With reference to FIG. 5, still another modified example (fourth embodiment) of the above embodiment will be described. In the third embodiment, the high dielectric material and the counter electrode are formed in a belt shape, so that a large nip portion is provided, and a heat generation area in contact with the sheet member is ensured, thereby making it possible to cope with high speed. However, in the structure of the third embodiment, since the high dielectric belt 106a and the conductive opposing belt 103b are in contact, when the sheet member coated with ink or toner is conveyed, the sheet member Depending on the material, there is a risk that the image contacts the belt before the ink or toner is melted and fixed on the sheet surface, and the image of the ink or toner is damaged or broken.

  Therefore, in the present embodiment, as shown in FIG. 5, the upstream stepping motor 140a, the downstream stepping motor 140b, and the upper unit movable that move the unit (referred to as the upper unit in this description) that operates the conductive facing belt 103b up and down. In addition to the screw portion 141 and the threaded bracket 142, a sensor 143 for confirming the home position is further provided on the upstream side and the downstream side. In addition, this configuration provides a mechanism that can change the inclination of the upper unit between the upstream side and the downstream side.

  By doing so, depending on the type of sheet member and ink, the strength of the AC electric field can be weakened by increasing the gap between the upstream side and the lower unit (referring to a unit that operates the high dielectric belt 106a), By gradually going to the downstream side, it becomes possible to apply high heat to the ink or toner on the image, and it becomes possible to gradually dry and spread, reducing the risk of damaging or destroying the image. In addition, by changing the gap between the upper unit on the upstream side and the downstream side with respect to the lower unit, the intensity of the AC electric field can be changed, and it becomes possible to gradually apply heat to the ink and toner. Heating according to the toner and sheet type is possible.

A specific configuration and operation will be described below.
In order to fix the toner on the sheet member to which the toner or ink is applied, it is necessary to melt the toner. Also, heat and pressure are required to dry the ink. As shown in FIG. 5, this embodiment includes conductive rollers 103a and 105a, a high dielectric belt 106a, a high frequency dielectric power supply circuit 101, and a conductive counter belt 103b as heat sources. Since the basic principle of heat generation has been described above, it will be omitted here and a specific operation will be described.

  First, in a system in which the fixing device is mounted, an upper unit having a conductive opposing belt 103b is transmitted simultaneously with a print start signal transmitted from the system to the high frequency dielectric control circuit 100 before the conveyance of the sheet member 121 is started. When the sheet, ink, toner information and the like are transmitted to the drive control circuit (not shown), the upper unit drive control circuit sends the upper unit and lower unit (conducting rollers 103a, 105a based on the information previously stored in the ROM). Voltage information for adjusting the gap information of the unit having the high dielectric belt 106a and the strength of the applied AC electric field is generated, the voltage information is transmitted to the high frequency dielectric control circuit 100, and the high frequency dielectric power supply circuit 100 is supplied with the AC electric field. Set the value.

  The gap information is transmitted to a driver circuit for driving the upstream and downstream stepping motors 140 for gap adjustment from the home position and a control circuit for controlling the rotation speed of the stepping motor 140 based on the gap information. After that, by rotating the stepping motor 140 with the upper unit operating screw portion 141 provided on the upstream and downstream sides, the screw-processed bracket 142 whose mounting angle is freely changed is returned to return the upstream and downstream sides of the upper unit. Each side gap is varied. Note that the “stepping motor 140” is a designation of a stepping motor that is intended not to specify the upstream side or the downstream side, or to indicate both.

  Next, the high-frequency dielectric control circuit 100 turns on the high-frequency dielectric power supply circuit 101 and sets the AC voltage and frequency of the high-frequency power supply so that the target value is set based on the voltage information. Next, since the fixing device needs to heat the fixing device in order to apply heat to the sheet member 121 coated with toner or ink, the high frequency dielectric control circuit 100 and the high frequency dielectric power supply circuit 101 change the rotating electrode. An AC electric field is applied to the connected conductive roller 105a and the high dielectric belt 106a attached so as to contact the roller and the conductive opposing belt 103b. As a result, a molecular dipole in a high dielectric covering the periphery of the conductive roller 105a is vibrated at a high speed by applying an AC electric field at a high frequency, and heat is generated by causing collision, vibration, friction, and the like.

  Furthermore, in this embodiment, as shown in FIG. 5, a plurality of fixed electrodes 109 are provided inside the high dielectric belt 106a. For this reason, when an AC electric field is applied by the high frequency dielectric power supply circuit 101, rapid and uniform heat generation occurs. In this embodiment, a plurality of fixed electrodes are provided on the inner side of the high dielectric belt 106a in both FIGS. 4 and 5, but in this embodiment, various dry distances can be obtained by subdividing and consolidating the fixed electrode width. If the drying distance is fixed, a single plate electrode is also possible.

  In this AC power supply circuit, the return current from the conductive roller 103a in contact with the conductive opposing belt 103b and the temperature sensor provided on the surface of the high dielectric belt 106a are used to measure the voltage, current, The frequency is constantly monitored to prevent abnormal temperatures, to maintain the heat generation temperature of the high dielectric relative to the target temperature, and to control the temperature fluctuation due to the difference in material and thickness when the sheet member 121 passes. A function is also provided.

  Next, when the fixing device reaches a target temperature, a signal indicating that the sheet member 121 is ready for fixing is transmitted from the high frequency dielectric control circuit 100 to the system. At the same time, the upper unit and the lower unit are moved to the upper and lower drive gears. The rotation starts after 144 is changed. At this time, if the upper unit and the lower unit are not completely in contact with each other, only the lower unit rotates to suppress power consumption, and the upper unit may not rotate. Upon receiving this signal, the system starts transporting the sheet member 121 coated with the toner and ink produced by the image forming function, and transports the sheet member 121 to the main fixing device through the pair of sheet member transport rollers 120. When the heat generation, the conductive facing belt 103b and the high dielectric belt 106a are in contact, the toner can be melted by the applied pressure. Further, the ink can be dried and fixed on the sheet member 121.

  After fixing, the sheet member 121 is again discharged to the sheet discharge device of the system by the sheet member conveying roller pair 120, and a series of fixing operations is completed. At this time, the fixing device confirms with the sensor that the sheet member 121 has left the fixing device. Then, a stop signal is transmitted from the high-frequency dielectric control circuit 100 to the high-frequency dielectric power supply circuit 101 to stop the output of the high-frequency power supply and at the same time stop the movement of the fixing unit (comprising an upper unit, a lower unit and a drive and control circuit).

  At this time, the upper unit moving screw part 141 is rotated by rotating the stepping motor 140 to return the screw-processed bracket 142 whose mounting angle is freely changed, so that the gap between the upstream side and the downstream side of the upper unit is reduced. Move each in the direction of narrowing and return to the home position. At this time, when the sheet member 121 is continuously conveyed, the high-frequency power output and the gap between the fixing units are kept as they are in order to prevent the heat generation temperature of the fixing device from decreasing.

  According to the present embodiment described above, it is possible to adjust the influence on the strength of the alternating electric field and the printed matter further than the above-described embodiments. Therefore, optimum drying applied to the sheet member is possible.

  In the first and third embodiments, the roller (the conductive counter roller 103 in FIG. 2) and the belt (the conductive counter belt in FIGS. 4 and 5) at the position opposite to the high dielectric member 106 are used. 103b), when the solid metal is used, the toner or ink applied to the sheet member 121 is partially stuck to the metal surface due to the pressure of the high dielectric cola or belt, and the image peeling on the surface of the sheet member is performed. Will be caused.

  Therefore, it is preferable to perform a surface treatment of a releasable material (for example, silicon or Teflon) that allows electromagnetic waves to pass through the member of the sheet member 121 that contacts the toner or ink application surface. By doing so, the strength of the adhesion force of the toner and the ink agent to the sheet member 121 is greater than the adhesion force of the toner and the ink to the member that contacts the toner and the ink application surface, and the separation of the toner and the ink can be prevented. . FIG. 6 shows an example in which such a releasable material 107a is surface-treated to a high dielectric belt 106a. Note that the technical idea of processing the surface of the releasable material 1007a can be applied to the high dielectric member 106 and the low dielectric member 107 in the first and second embodiments.

  In the description of the second embodiment described above, it has been described that the high dielectric is covered with a low dielectric member so as not to evaporate the high dielectric, and the heat generating layer is multilayered. However, depending on the size and shape of the apparatus, there may be a case where the unit for performing the main fixing or drying cannot be enlarged. In particular, when the belt shape shown in FIGS. 4 and 5 is used, it is necessary to process the heat generating layer as thin as possible.

  Therefore, as shown in FIG. 6, a rubber member or a Teflon member is formed into a film shape, an adhesive layer is provided between the films, and the layers are laminated to obtain an arbitrary diameter shape. At this time, in the adhesive layer, it is desirable to use a high dielectric adhesive (such as vinyl acetate, urethane, vinyl, or vinyl urethane material) in order to increase the temperature or adjust the temperature.

Furthermore, in order to accelerate or adjust the temperature rise, it is generally said that the amount of heat generated by dielectric heating can be calculated by the following equation.
P = 1 / 1.8 * 10 ⁻¹⁰ * ε′r · tan δ · f · E ² (W / m ³ )
P: Calorie (W / m ³ )
ε′r · tan δ: loss factor f: frequency (Hz)
E: Electric field strength (V / cm)
From the above, the amount of heat is proportional to the frequency and proportional to the loss factor.

From this, the loss factor of the substance is as follows.
ε′r = ε′r · tan δ
ε′′r: dielectric loss
ε′r: relative permittivity
tan δ: Dielectric loss tangent From the above, members having different relative dielectric constants and dielectric loss tangents (dielectric heating promoting members) are added to the adhesive. By doing so, further temperature rise and temperature rise control can be expected. For example, ABS, PC, PA6, PVC, PE, PEEK, LCP, POM, PES, PEI, PBT, PPS, PSF and other resins, NaCl (sodium chloride), carbon powder, ceramic powder, and the like are added.

DESCRIPTION OF SYMBOLS 100 High frequency dielectric control circuit 101 High frequency dielectric power supply circuit 102 Rotating electrode 103 Conductive counter roller 104 Rotating electrode 105 Conductive roller 106 High dielectric member 107 Low dielectric member 108 Shield cover 120 Sheet member conveyance roller pair 121 Sheet member 122 Cleaning mechanism 103a conductive roller 103b conductive opposite belt 105a conductive roller 106a high dielectric belt 107a releasable material 140a upstream stepping motor (gap adjustment motor)
140b Downstream stepping motor (gap adjustment motor)
141 Upper unit moving screw part

Japanese Patent No. 4515175 JP 2008-129540 A

Claims (6)

A high frequency dielectric control circuit;
A high-frequency dielectric power supply circuit controlled by the high-frequency dielectric control circuit;
A first conductive rotor to which the high-frequency dielectric power supply circuit is connected;
A high dielectric member covering the first conductive rotating body;
A second conductive rotator provided at a position facing the first conductive rotator and connected to the high-frequency dielectric power supply circuit;
The high-frequency dielectric power supply circuit applies a high-frequency AC electric field voltage to the first and second conductive rotors,
The first conductive rotator is provided below the second conductive rotator,
High dielectric member covering the first electrically conductive rotating object is a gel-like, is contained in the low dielectric member through electromagnetic waves,
The fixing device , wherein the high-frequency dielectric power supply circuit monitors the voltage, current, or frequency of the AC electric field based on a return current from the second conductive rotating body . A plurality of the first conductive rotating bodies are provided,
The high dielectric member has a belt shape and is cross-linked to the plurality of first conductive rotating bodies;
The fixing device according to claim 1, wherein a fixed electrode is provided between the plurality of first conductive rotators.   The fixing device according to claim 1, wherein an interlock function is provided for opening and closing a shield cover that covers the fixing device.   4. The fixing device according to claim 1, wherein the member that contacts the toner or ink application surface of the sheet member is subjected to surface processing with a releasable material. 5.   5. The fixing device according to claim 1, further comprising a mechanism capable of arbitrarily changing a gap between the first conductive rotator and the second conductive rotator. 6. .   An image forming apparatus comprising the fixing device according to claim 1.

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