JP2004062026A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device which secures energy-saving with a simple constitution regardless of the surface state of a fixing member. <P>SOLUTION: In a fixing device 11 provided with first and second fixing members 11 and 12 opposed to each other at the fixing position of a recording material carrying an unfixed toner image, one of the fixing members 11A is provided with: a heat recovering member 13 to recover the residual heat of the fixing member 11A after fixing by coming into contact with a heat source 12A to heat the fixing member 11A and the fixing member 11A; and a heat supply member 14 to supply the fixing member 11A with recovered heat before heating by the heat source 12A. The heat recovering member 13 and the heat supply member 14 individually come into contact with each other by corresponding to the surface state (13A) of the fixing member 11A. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing device and an image forming apparatus using the same, and more particularly, to a heat exchange mechanism.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a printing machine, a fixing process is performed to prevent a developed toner image transferred from a photoconductor forming a latent image carrier from peeling off from a transfer medium. Is executed.
In the fixing step, for example, an operation of permeating and fusing toner to a sheet or the like as an image carrier in a state where the toner used for the development process is melted by heating and pressing is adopted.
[0003]
As one of the fixing methods, there is a configuration using a belt wrapped around a plurality of rollers including a roller having a built-in heat source. This configuration has an advantage that the time required to start up to a predetermined fixing temperature can be reduced by using a belt having a small heat capacity as compared with a configuration using a heat roller fixing method in which rollers are opposed to each other.
[0004]
In the belt fixing method, the above-described fixing process is performed by the belt heated by the heat source coming into contact with the toner. As a heat source method for heating the belt, control and configuration are relatively simplified. An easy resistance heating method is often used.
[0005]
The resistance heating method used as a heat source consumes extremely high power, and is not preferable in terms of energy saving, which has been increasing in demand in recent years.
On the other hand, it is important for the toner to be subjected to the fixing process to be cooled and hardened as soon as possible when it penetrates into the transfer medium in a state where the toner is melted and softened by heating, in order to prevent the occurrence of the offset phenomenon. Therefore, from the viewpoint of energy saving, it is conceivable to reduce the fixing temperature by lowering the power consumption of the heat source.
In terms of lowering the fixing temperature, in terms of the material of the toner, in this case, a toner having a low softening point or melting point is necessarily selected, but the thermoplastic resin used in the toner is used. As a characteristic of, there is a property that when the softening point or melting point is lowered, the melt viscosity is necessarily lowered. In this property, the softening point or melting point of a thermoplastic resin is determined by the molecular weight, molecular weight distribution, crystallinity, cross-linking degree, and intermolecular force of the resin. It is necessary to lower the molecular weight and the degree of crosslinking or narrow the molecular weight distribution. Of these, the lower limit of the molecular weight distribution is determined from the limit of the storage stability of the resin, and therefore, if the molecular weight itself is reduced, the molecular weight becomes narrower inevitably.
[0006]
In general, when the molecular weight is reduced, the entanglement is loosened because the molecular chain is shortened, and the melt viscosity is lowered. Further, even when the molecular weight distribution becomes narrow, the entanglement of the molecular chains is also loosened, and the melt viscosity is lowered. Further, when the degree of cross-linking between molecules is reduced, each molecule becomes easy to move, so that the melt viscosity decreases. For this reason, when the fixing temperature is lowered, the offset phenomenon is likely to occur due to the characteristics of the toner, and a configuration for eliminating the offset phenomenon has been proposed (for example, Japanese Patent Publication No. 51-29835). . This publication discloses a configuration in which heat is applied to an object to be fixed in a fixing unit using a film sheet, and then the film is cooled while maintaining the adhesion between the film sheet and the object to be fixed, and the toner is solidified and then peeled off. Further, there is disclosed a configuration in which corrective cooling is performed in order to accelerate the cooling effect of the toner. As a method of promoting the latter cooling effect of toner, there is a configuration described in JP-A-5-273876 or JP-A-2001-22198.
[0007]
In JP-A-5-273876 and JP-A-2001-22198, a cooling means is provided at a position corresponding to the belt after the belt passes through the fixing nip portion, or the fixing nip portion is moved in the belt moving direction. There is disclosed a configuration in which a roller around which a belt passes through is used as cooling means.
[0008]
[Problems to be solved by the invention]
In the case of using forced cooling by air blowing, the surrounding air is caused to flow at the time of air blowing, thereby cooling other than the cooling points, or a device that dislikes temperature rise due to the dissipation of hot air by air blowing, for example, melting by heat occurred The coagulation that occurs later will adversely affect devices that contain toner that is likely to cause blocking. If water or another liquid is used as the heat medium instead of the air blowing, the equipment including the circulation path becomes large, which may lead to an increase in the size of the apparatus.
[0009]
As a configuration for suppressing the heat generated in the fixing device from affecting the peripheral portion, there is a configuration in which the fixing device is thermally isolated from the peripheral portion instead of cooling the members used in the fixing device. Specifically, a heat shield wall is provided that surrounds the entire area or a part of the fixing device excluding the fixing nip portion. In this configuration, the radiation of radiant heat or convective heat from the fixing device can be suppressed. However, even when such a configuration is adopted, if the temperature rises due to the heat storage of the heat shield wall itself, the ambient temperature around the temperature rises, and as a result, similar to the case of the cooling configuration described above, , Causing a toner blocking phenomenon or the like.
[0010]
As described above, the main purpose of the cooling or heat-shielding structure in the fixing device is to prevent the generated heat from being dissipated, and a part of the generated heat remains unused so that the energy consumption efficiency is reduced. It becomes worse, and it becomes difficult to achieve energy saving.
[0011]
As a configuration for effectively utilizing the heat generated in the fixing device, when the case of the belt fixing method is targeted, by transmitting the heat of the expanded portion heated by the heat source to the expanded portion of the reheating area that has passed through the cooling unit, A configuration for performing so-called heat exchange has been proposed (for example, Japanese Patent Application Laid-Open No. 2001-22198).
[0012]
In the above-mentioned publication, a heat exchanger is provided in contact with both sides of the extending portion of the belt, and after the heating, the extended portion that has passed through the fixing nip portion is absorbed by cooling, and the heat is opposed to the extended portion and the heat source. It is designed to transmit to the front extension. Further, there is disclosed a configuration in which a Peltier element capable of switching between heating and cooling by power supply is used as a heat exchanger to efficiently change the temperature at each of the extended portions on the cooling side and the heating side.
[0013]
However, this configuration has the following problem.
The Peltier element used to efficiently change the temperature at each extended portion requires an external power supply, and therefore requires a dedicated power supply for this element. This is a configuration in which a power consuming part is added separately from the heat source to be used, which goes against energy saving.
The Peltier element has a structure in which the surface layer is formed in an ingot or disk shape having a sandwich structure by ceramics provided on the surface layer, and is made rigid by ceramics. For this reason, it may be damaged if bent. For this reason, as shown in the above publication, the Peltier element is arranged to be brought into contact with a flat surface of another belt having a surface that comes into contact with the fixing belt or arranged to be brought into contact with the flat extended surface of the fixing belt. Will be adopted.
[0014]
When a Peltier element is used, heat exchange for the belt can be performed by being able to perform auxiliary heating and cooling, but the belt used in the fixing device conforms to the structure of the Peltier element as described in the above publication. It is not limited to one having a flat surface extending portion, and may have a curved extending surface. In such a case, there is a possibility that a heat exchanger capable of performing auxiliary heating and cooling cannot be used. In addition, in the above publication, one of the rollers around which the belt is wound is provided as a heating member having a heat source, and the other of the rollers is provided as a cooling member. As a result, the configuration may be complicated.
[0015]
Further, in the Peltier element, thermal conductivity of ceramics located on a surface layer portion is poor, so that a steep temperature change cannot be expected. Therefore, it is necessary to increase the power in order to select a steep temperature change, and as a result, the power consumption is likely to increase, so that energy may not be saved.
[0016]
SUMMARY OF THE INVENTION An object of the present invention is to provide a configuration in which energy saving can be ensured by a simple configuration regardless of the surface configuration of a fixing member, in view of the problem in the conventional fixing device described above, particularly, a fixing device in which the surface configuration of the fixing member is not flat. It is an object of the present invention to provide a fixing device and an image forming apparatus having the same.
[0017]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a fixing device including first and second fixing members facing each other at a fixing position of a recording material carrying an unfixed toner image, wherein one of the fixing members is heated by heating. A heat recovery member that contacts the fixing member and recovers residual heat of the fixing member after fixing in contact with the fixing member; and a heat supply member that supplies the recovered heat to the fixing member before heating by the heat source. The heat recovery member and the heat supply member are in contact with each other according to the surface configuration of the fixing member.
[0018]
According to a second aspect of the present invention, in addition to the first aspect, one of the fixing members has a curved surface.
[0019]
According to a third aspect of the present invention, in addition to the first aspect, the heat recovery member has a structure that can be bent along a surface of the fixing member.
[0020]
According to a fourth aspect of the present invention, in addition to the first aspect, one of the fixing members is formed of a belt, and the heat recovery member is formed of a flexible sheet. I have.
[0021]
According to a fifth aspect of the present invention, in addition to the first aspect, one of the fixing members is constituted by a roller having a built-in heat source, and the heat recovery member is located near an outer periphery of the fixing member. The heat supply member is arranged so as to be in contact with the outer periphery of the fixing member.
[0022]
According to a sixth aspect of the present invention, in addition to the first aspect of the present invention, the heat supply member is a good thermal conductor having a surface in contact with the heat recovery member and the fixing member. It is characterized by being constituted.
[0023]
According to a seventh aspect of the present invention, in addition to the first aspect, the heat recovery member and the heat supply member are configured to set the amount of heat supplied using an electromotive force generated corresponding to the recovered heat. It is characterized by having.
[0024]
According to an eighth aspect of the present invention, in addition to the seventh aspect, a member capable of utilizing a thermoelectric effect such as a Seebeck effect or a Peltier effect is used as the heat recovery member and the heat supply member.
[0025]
According to a ninth aspect of the present invention, in addition to the first aspect, the heat recovery member is provided near the fixing member, and the heat supply member contacts the fixing member. The heat supply member is provided so as to be in contact with the heat supply member and generates heat by an electromotive force generated in response to heat recovered in the heat recovery portion.
[0026]
According to a tenth aspect of the present invention, in addition to the ninth aspect, the heat recovery member is located at least above the fixing member.
[0027]
According to an eleventh aspect of the present invention, in addition to the seventh or eighth aspect, the heat recovery member forms a contact surface by arranging the resistor elements in a state of being spread within a predetermined area. Features.
[0028]
According to a twelfth aspect of the present invention, in addition to the eleventh aspect, the register element is disposed so as to be continuously folded repeatedly within a predetermined area.
[0029]
According to a thirteenth aspect of the present invention, in addition to the eleventh or twelfth aspect, the register element is provided with a sandwich structure in which thin films are positioned on both front and back surfaces.
[0030]
According to a fourteenth aspect of the present invention, in addition to the one of the eleventh to thirteenth aspects, the plurality of register elements are arranged in parallel.
[0031]
The invention according to claim 15 is characterized in that, in addition to the invention described in any one of claims 11 to 14, the register element can be independently turned on and off.
[0032]
According to a sixteenth aspect of the present invention, in addition to the one of the eleventh aspect or the fourteenth aspect, it is preferable that an arrangement interval of the resistor elements within a predetermined area is 0.01 to 5 mm. Features.
[0033]
According to a seventeenth aspect of the present invention, in addition to the one of the eleventh aspect or the fourteenth aspect, the register element is arranged such that an arrangement interval within a predetermined area is 0.01 to 5 mm. Features.
[0034]
In the invention according to claim 18, in addition to the invention according to any one of claims 7 or 8 and 11 to 16, the electromotive force corresponding to the heat recovered by the heat recovery member corresponds to the supplied heat amount control. This is characterized in that it is applied to a heat supply member adjusted to a voltage corresponding to the amount of heat generated.
[0035]
According to a nineteenth aspect, in addition to the ninth or tenth aspect, the heat recovery member is provided with a forced cooling unit.
[0036]
According to a twentieth aspect, the fixing device according to any one of the first to nineteenth aspects is used for an image forming apparatus.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a schematic diagram showing an example of an image forming apparatus to which a fixing device according to an embodiment of the present invention is applied.
The image forming apparatus shown in FIG. 1 also has a copying function capable of forming an electrostatic latent image on a photosensitive member serving as a latent image carrier based on image information obtained by reading a document and image information from a host computer or the like. The printer is a full-color printer that can perform visible image processing of an electrostatic latent image using a plurality of colors.
[0038]
In FIG. 1, a photosensitive member 2 which is a drum-shaped latent image carrier is arranged inside an image forming apparatus 1.
Around the photoconductor 2, a charging device 3, a writing device 4, a developing device 5, a transfer device 6, and a cleaning device 7, which execute image forming processing along the rotation direction of the photoconductor 2, are arranged.
[0039]
The writing device 4 used in the image forming apparatus 1 according to the present embodiment is provided with a laser light source capable of emitting a laser beam in accordance with an image signal from a control unit (not shown). However, writing light is emitted not only by an output signal from a computer but also by an image signal based on a document image read by a scanner 8 provided in the image forming apparatus 1. That is, the image forming apparatus 1 is provided with a document placing table 1A on the upper surface of the housing so that a document can be placed thereon, and a scanner 8 for reading a document image is provided below the document placing table 1A. Is provided.
The scanner 8 includes a reading optical system and a reading element having a well-known structure, and image information obtained by the reading element is output to the control unit.
[0040]
The writing device 4 is provided with a polygon mirror 4A, an fθ lens 4B, a BTL lens 4C, and a writing mirror 4D in addition to a laser light source (not shown), although not shown. The scanner 8 includes a scanning light source and a reflecting mirror. A first scanner unit 8A movable parallel to the document table, a second scanner unit 8B movable with a pair of mirrors for optical path conversion, a lens 8C and a CD element as an optical reading element. Provided substrate 8D.
[0041]
The transfer device 6 in the present embodiment includes a primary transfer device 6A for primary transfer of a visible image from the photoconductor 2 and a secondary transfer for secondary transfer from the primary transfer device 6A to a sheet such as a recording sheet. The device 6B is provided.
The primary transfer device 6A includes an intermediate transfer belt 6A1 wrapped around a plurality of rollers, and the primary transfer charger 6A2 disposed at a position where the intermediate transfer belt 6A1 and the photosensitive member 2 face each other. Can be transferred to the intermediate transfer belt 6A1.
An image of a color having a complementary color relationship with color separation can be superimposed and transferred to the intermediate transfer belt 6A1 by a developing device 5 described later, and the superimposed transferred image is recorded by a secondary transfer device 6B on a recording paper or the like. (Hereinafter, referred to as a sheet).
[0042]
The secondary transfer device 6B is composed of a charging roller that can be brought into contact with and separated from the intermediate transfer belt 6A1 in the primary transfer device 6A with the sheet conveyance path interposed therebetween, and the intermediate transfer is performed while nipping and conveying the moving sheet. The superimposed image on the belt 6A1 can be electrostatically transferred to a sheet.
The secondary charging device 6B can come into contact with the intermediate transfer belt 6A1 only at the time of transfer of a single color and at the time of collective transfer of a superimposed image. When the image of each color is transferred to the intermediate transfer belt 6A1, the intermediate transfer belt 6B can be used. The image is not disturbed by not touching 6A1.
[0043]
The sheet is fed by the sheet feeding device 9 to a secondary transfer position corresponding to a position where the intermediate transfer belt 6A1 and the secondary transfer device 6B face each other.
The paper feeding device 9 includes a paper feeding cassette 9A capable of storing recording paper, a feeding roller 9B for feeding out a sheet in the paper feeding cassette 9A, a separation roller pair 9C, a conveyance roller 9D, and a registration roller 9E. The sheet separated from the inside of the sheet feeding cassette 9A toward the next transfer position is fed after the registration timing is set by the registration roller 9E.
[0044]
In the present embodiment, it is also possible to feed a sheet of a different size or a different type from the sheet cassette. For this reason, a manual feed tray 9F is provided in the housing of the main body of the image forming apparatus, and a part of the manual feed tray 9F can be turned upside down. The movement of the sheet fed from the paper feed tray 9A between the manual feed tray 9F and the registration rollers 9E is performed. A transport roller 9D is disposed at a position where the roads join, and a feed roller 9B is disposed near the manual feed tray 9F.
[0045]
In the above configuration, the electrostatic latent image formed on the photoconductor 2 is subjected to visible image processing by the developing device 5 and transferred to the intermediate transfer belt 6A1 by the primary transfer device 6A.
When the image is a single color, the transfer image on the intermediate transfer belt 6A1 is secondarily transferred as it is to the sheet fed from the sheet feeding device 9 by the secondary transfer device 6B, and when the image is a plurality of colors, the intermediate transfer is performed. After the superimposed transfer onto the belt 6A1, the sheet is collectively transferred to the sheet by the secondary transfer device 6B.
The sheet after the secondary transfer is separated from the secondary transfer position, conveyed to the fixing device 11 via the conveying device 10, where the image is fixed and discharged.
[0046]
Hereinafter, an embodiment of the fixing device 11 according to the first to fourth and sixth aspects and the eleventh to fifteenth and seventeenth aspects will be described.
FIG. 2 is a diagram for explaining the principle configuration of the fixing device according to the embodiment of the present invention. The fixing device 11 shown in FIG. The image forming apparatus includes first and second fixing members 11A and 11B opposed to each other at a fixing position corresponding to a fixing nip portion capable of heating and pressing T, and a belt (hereinafter, referred to as a fixing belt 11A) is used for one of the fixing members. ing.
As the other fixing member, a pressure belt 11B that presses a sheet against the fixing belt 11A is used, and the fixing device 11 is configured to adopt a belt fixing method.
The fixing belt 11A is wound around a pair of rollers 12, 13, and one of the extending portions formed between the rollers moves in the same direction while abutting on the pressure belt 11B.
The fixing belt 11A is maintained at a fixing temperature by being heated by a heat source 12A using a resistance heating method built in one of the rollers 12 around which the fixing belt 11A is wound.
The heat source 12A is feedback-controlled by a temperature sensor (not shown) that detects the surface temperature of the fixing belt.
[0047]
On the fixing belt 11A, a heat recovery member 13 that is in contact with the inner side surface in the area of the fixing nip portion is arranged.
The heat recovery member 13 is brought into contact with the fixing belt 11A at a position where the residual heat after the fixing can be recovered in the fixing nip portion, and a fixing surface located on the side opposite to the fixing nip portion side on a surface opposite to the contact surface. It is integrated with the heat supply member 14 that contacts the extended surface of the belt 11A.
[0048]
The heat supply member 14 is made of a noble metal such as gold, silver and copper, or a good heat conductor such as aluminum. The heat supply member 14 is on the side that is in contact with the expanded surface of the fixing belt 11A, which is the opposite side to the integrated surface with the heat recovery member. The surface is positioned at the position before reheating by the heat source 12A.
[0049]
As the heat recovery member 13, a member is used in which both of the front and back surfaces can perform both cooling by heat absorption and heating by heat generation by power supply, which is one of the thermoelectric effects. In the configuration shown in FIG. Have been.
[0050]
The register element 13A is configured to be able to contact the surface of the fixing belt 11A according to the surface configuration thereof, and the arrangement interval between adjacent elements within a predetermined area is set to about 0.01 to 5 mm as shown in FIG. In this case, a sheet-like structure is used, which is repeatedly folded back and forth in a continuous state, or a sandwich structure sandwiched between thin films on both front and back sides. To be able to bend and deform.
[0051]
When the heat recovery member 13 is energized to the resistor element 13A, the surface in contact with the fixing belt 11A functions as a cooling surface, and the surface on the opposite side functions as a heat generating surface. Therefore, the heat supply member 14 integrated on the opposite side is heated, and the fixing belt 11A is preheated by the heat source 12A before reheating.
[0052]
In the present embodiment, the heat recovery member 13 can be brought into contact with the surface configuration of the fixing belt 11A according to the above configuration, so that a part of the fixing belt 11A has a curved surface as shown in FIG. However, it is possible to bend and deform according to the surface configuration. As a result, uniform contact can be made regardless of the surface configuration of the fixing belt 11A, so that heat absorption from the fixing belt 11A, that is, cooling unevenness can be eliminated, and the cooling effect of the fixing belt 11A can be enhanced.
[0053]
The configuration shown in FIG. 4 is a configuration based on the principle configuration shown in FIG. 2. In this configuration, the fixing belt 1A is wound around only the roller 12 having the heat source 12A therein, instead of a pair of rollers. Instead of the roller 13 shown in FIG. 2, an end in the extension direction is guided by a support member 11A1 that can guide the fixing belt 11A.
The support member 11A1 has a curved surface capable of pressing the fixing belt 11A against the pressure belt 11B side. The curved surface enlarges the fixing nip portion and makes the contact pressure with the toner T uniform, thereby reducing the unevenness in fixing due to uneven heating. It is designed to prevent occurrence. Therefore, the heat recovery member 13 is formed in contact with the curved surface of the fixing belt 11A.
[0054]
On the other hand, when the heater element 13A is energized, heat is generated on the surface opposite to the cooling surface, and the heat is transmitted to the heat supply member 14, so that the fixing belt 11A in contact with the heat supply member 14 It will be heated. Thereby, while cooling of the fixing belt 11A is promoted, cooling and curing of the toner to be fixed is promoted, and power consumption in the heat source 12A can be suppressed by preheating the fixing belt 11A.
[0055]
The resistor element 13A used for the heat recovery member 13 has a structure in which it is continuously folded back to be spread within a predetermined area as shown in FIG. 2, and a plurality of resistor elements 13A as shown in FIG. Can be juxtaposed. Also in this case, similarly to the above-described configuration, the arrangement interval between adjacent ones is set to 0.01 to 5 mm. This interval is set to eliminate temperature unevenness within a predetermined area.
[0056]
The control of energization of the resistor element 13 shown in FIGS. 2 and 5, that is, the on / off setting, is performed with reference to the temperature of the fixing belt 11A on the surface to be cooled or the surface on which heat is generated. That is, for the on / off setting, the thermocouple 13B whose operation state is switched at a predetermined temperature is used.
[0057]
The energization control of the resistor elements 13A for the configuration shown in FIG. 5 can be performed for each of the resistor elements 13A, so that fine temperature management can be performed corresponding to the surface temperature of the fixing belt 11A. That is, when the surface temperature of the fixing belt 11A is higher than the predetermined temperature, the power supply to any one of the register elements 13A is stopped.
Thus, the temperature control of the fixing belt 11A by the register element 13A is automated. As described above, the heat radiated by the cooling is used for heating the fixing belt 11A, so that the heat is circulated.
[0058]
In the above-described embodiment, since the rigid element 13 bends and deforms with respect to the fixing belt 11A as a fixing member, uniform contact can be made according to the surface configuration of the fixing belt 11A. It can be pressed by the collection member 13. As a result, the contact pressure of the fixing belt 11A with respect to the sheet S is increased, the contact with the toner T can be improved, and the efficiency of heat supply to the toner T can be increased. In addition, since the state of contact between the fixing belt 11A and the heat recovery member 13 after fixing is also improved, the efficiency of recovering residual heat is enhanced, the cooling effect of the toner is promoted, and the molten toner is reversely transferred to the transfer belt 11A. Can be reliably prevented.
[0059]
Next, an embodiment of the fixing device according to the inventions of claims 5, 7 to 10, 16 and 18 will be described.
This embodiment is characterized in that an electromotive force is generated corresponding to the heat recovered by the heat recovery member, and the fixing member is preheated by the heat supply member using the electromotive force.
In the fixing device 20 shown in FIG. 6, the first fixing member is constituted by a fixing roller 21 having a built-in heat source 21A, and the second fixing member is opposed to the fixing roller 21 so as to form a fixing nip. It is constituted by a roller 22.
[0060]
Unlike the configuration shown in FIG. 2, the heat recovery member 23 is arranged near the outer periphery of the fixing roller 21, and is arranged in a range including at least above the fixing roller 21. In the configuration shown in FIG. 6, the fixing rollers are arranged on three sides except for a fixing nip portion which is opposed to and abuts on the pressure roller 22. As a result, heat dissipated from the fixing roller 21 can be efficiently absorbed.
[0061]
As the heat recovery member 23, a member that can use the Seebeck effect or the Peltier effect, which is a thermoelectric effect of generating an electromotive force by a temperature difference based on the recovered heat, is used. In the configuration illustrated in FIG. 6, a thermocouple or a Peltier element is used. .
When a thermocouple or a Peltier element is used as the heat recovery member 23, particularly when a Peltier element is used, the material is ingot-shaped or disk-shaped, and as shown in FIG. It is also possible to dispose it only above the fixing roller 21 corresponding to a position where heat is easily absorbed.
[0062]
Since the heat recovery member 23 has a thermoelectric effect, it can be used as a flexible member capable of bending and deforming in a shape following the outer peripheral surface of the fixing roller 21 as shown in FIG. It is also possible to adopt a possible register element (for convenience, indicated by reference numeral 23 '). In this case, the configuration shown in FIG. 3 or FIG.
[0063]
The heat recovery members 23 and 23 ′ are connected to the input side of the voltage stabilizing device 24, and the output side of the voltage stabilizing device 24 is connected to a heat supply member 25 that contacts the peripheral surface of the fixing roller 21. ing.
The voltage stabilizing device 24 is a device that manages the temperature of the heat supply member 25, and can control an applied voltage including ON / OFF control of the heat supply member 25 so that the surface temperature of the fixing roller 21 reaches a predetermined temperature. It has become. In FIG. 8, arrows indicated by broken lines indicate signal paths of feedback signals for performing temperature management of the heat supply member 25.
[0064]
The heat supply member 25 is composed of a roller member capable of generating heat by the electric power applied from the voltage stabilizing device 24. In this configuration, a resistance heating element or a lamp is used. It is also possible to affix a resistor element, which is a thermoelectric element capable of performing the above, to the peripheral surface of the roller.
[0065]
In the present embodiment, in the above-described configuration, when the heat radiated from the fixing roller 21 is absorbed by the heat recovery member 23, the electromotive force is generated due to the temperature difference between the fixing roller 21 side and the opposite side of the heat recovery member 23. The voltage is generated, and the electromotive force is taken into the voltage stabilizer 24.
[0066]
The voltage stabilizing device 24 controls the voltage applied to the heat supply member 25 in accordance with the surface temperature of the fixing roller 21, and performs preheating of the fixing roller 21 using the heat supply member 25. As a result, the surface temperature of the fixing roller 21 is maintained at a predetermined temperature by heating from the heat supply member 25 serving as a heat source other than the heat source 21A, so that power consumption in the heat source 21A can be reduced. In this way, by converting the exhaust heat remaining in the fixing roller 21 into heat energy for heating the fixing roller 21, the load on the heat source 21A can be reduced and energy can be saved.
[0067]
The inventor of the present invention has compared the power consumption of the above configuration with that of the configuration having the configuration. As a result, the configuration shown in FIG. 6 was able to confirm that the energy saving was about 10%, and the configuration shown in FIG. In the configuration shown in FIG. 8 and FIG. 8, although a loss of about 10 to 15% is caused due to the narrow arrangement area of the heat recovery members 23 and 23 ', the load reduction at the heat source 21A is apparent. Energy saving was confirmed as compared with the case where it was not used.
[0068]
In order to efficiently and particularly extract a large amount of electromotive force generated in the heat recovery members 23 and 23 ', it is necessary to increase the temperature difference between the heat recovery members 23 and 23'. Hereinafter, an embodiment of the invention described in claim 19 will be described with respect to this configuration.
In FIG. 9, a radiation fin 26 is provided as a forced cooling means for increasing the temperature difference between the surface facing the fixing roller 21 and the surface opposite to the fixing roller 21 for the heat recovery member 23 shown in FIG. A configuration is shown in which the airflow F is brought into contact with the fins 26 by a blowing means (not shown). As a result, the heat radiation area can be increased, and the temperature difference between the heat absorbing surface in contact with the fixing roller 21 and the defaced surface on the opposite side can be increased.
[0069]
FIG. 10 shows a configuration in which a heat exchanger 27 capable of circulating a heat medium as forced cooling means is provided on the surface opposite to the side facing the fixing roller 23 for the heat recovery member 23 having the configuration shown in FIG. It is shown. In this configuration, water or oil or the like is used as a heat medium, and heat exchange is performed by a heat medium circulating through a cooling unit (not shown), thereby increasing the temperature difference between the heat absorbing surface and the heat radiating surface of the heat recovery member 23. be able to.
[0070]
The inventor conducted an experiment on the energy saving effect of the configuration shown in FIGS. 9 and 10, and found that the configuration shown in FIG. 9 increased the energy conversion efficiency by about 20% or more as compared with the configuration shown in FIG. 10, the energy saving of 20% or more was confirmed in the configuration shown in FIG. 10 as compared with the configuration shown in FIG. In addition, it was confirmed that the temperature around the fixing device could be stopped within 40 ° C. With such a configuration, heat can be recycled by the recovered heat, thereby suppressing an increase in the load on the heat source, realizing energy savings, and quickly raising the temperature of the fixing member, and further improving the inside of the apparatus. Can be suppressed by heat exchange, so that it is possible to prevent a device disposed around the fixing device from being adversely affected by heat.
[0071]
In particular, in the case where the resistor element 23 'provided in a shape following the outer peripheral surface of the fixing rotor 21 is used, the peripheral surface of the fixing roller 21 is compared with the case where an ingot-shaped or disk-shaped member having a normal structure is used. It can be confirmed that the energy can be further saved by about 10% as compared with the configuration shown in FIGS. As a result, the energy saving efficiency is improved regardless of the form or shape of the fixing member.
[0072]
【The invention's effect】
According to the first to fourth and sixth aspects of the present invention, the heat recovery member can be brought into contact with the surface of the fixing member in accordance with the surface configuration. In particular, in the second and third aspects of the invention, the fixing member has a curved surface. Can be brought into contact with the surface thereof. Moreover, in the invention according to claim 4, since the heat recovery member is formed in a flexible sheet shape, the contact property with respect to a curved surface can be improved. As a result, the contact state between the heat recovery member and the fixing member is improved irrespective of the surface configuration of the fixing member, the efficiency of recovering residual heat is improved, and the recovered heat is provided to the fixing member before heating. be able to. As a result, it is possible to reduce the load on the heat source originally provided to the fixing member, thereby saving energy. In addition, since the fixing member can be brought into the pre-heating state before reheating, the rise of the fixing member to a predetermined temperature can be speeded up, and the waiting time until the start of fixing can be shortened.
[0073]
According to the fifth, ninth, and tenth aspects of the present invention, even when the fixing member is constituted by a roller having a built-in heat source, the heat recovery member is disposed at a position where heat can be recovered more effectively. Since the recovered heat can be resupplied to the fixing member, the load on the heat source on the fixing member side can be reduced by a relatively simple configuration.
[0074]
According to the seventh and eighth aspects of the present invention, heat generation or cooling can be performed using an electromotive force generated in response to the recovered heat, so that the power supply to the heat recovery member and the heat supply member is specially provided. The need for preparation can be eliminated. This makes it possible to prevent an increase in power consumption and increase the energy saving rate.
[0075]
According to the eleventh to thirteenth aspects, since the surface configuration of the fixing member is made to correspond to the use of the resistor element, the state of contact with the fixing member can be made uniform, and the efficiency of heat recovery and supply can be improved. In particular, in the invention according to Claims 12 and 13, the fixing member can be bent and deformed by continuously and repeatedly folding within a predetermined area or by being formed into a sandwich structure by a thin film, so that the surface of the fixing member has a curved surface. Even in this case, it is possible to increase the efficiency of heat recovery and supply by making uniform contact.
[0076]
According to the fourteenth to sixteenth aspects of the present invention, a plurality of fusista elements capable of making uniform contact with the fixing member are arranged in parallel, so that the amount of heat recovery and the amount of heat supply can be variously set within the maximum and minimum ranges. Therefore, optimal temperature control for the fixing member can be performed. In particular, in the invention according to claims 15 and 16, since the on / off setting can be independently performed between the resistor elements with reference to a predetermined temperature, heat recovery and supply can be finely controlled by own electromotive force to fix the fixing member. Appropriate temperature can be achieved without requiring a special power supply.
[0077]
According to the seventeenth aspect, by setting the arrangement intervals of the resistor elements, it is possible to prevent the occurrence of temperature unevenness on the surface of the fixing member.
[0078]
According to the nineteenth aspect, the heat recovery member is provided with forced cooling means to improve the efficiency of recovering residual heat and to increase the temperature difference, thereby increasing the amount of generated electromotive force and increasing the amount of heat supply. The drop can be prevented. In addition, it is possible to quickly secure the amount of heat required for the supply.
[0079]
According to the twentieth aspect, it is possible to recover the residual heat generated in the fixing member having the heat source and to heat the fixing member before reheating. Since the generated electromotive force is used, the heat accumulated in the fixing member can be circulated, whereby the load on the existing heat source can be reduced and energy can be saved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of an image forming apparatus to which a fixing device according to an embodiment of the present disclosure is applied.
FIG. 2 is a schematic diagram for explaining a principle configuration of a fixing device according to an embodiment of the present invention.
FIG. 3 is a view for explaining a configuration of a heat recovery member used in the fixing device shown in FIG. 2;
FIG. 4 is a diagram for explaining an operation in the principle structure shown in FIG. 2;
FIG. 5 is a view for explaining another configuration of the heat recovery member shown in FIG. 2;
FIG. 6 is a diagram for explaining another configuration of the fixing device according to the embodiment of the present invention.
FIG. 7 is a diagram showing a partially modified example of the configuration shown in FIG. 6;
FIG. 8 is a diagram showing still another modified example of the configuration shown in FIG. 7;
FIG. 9 is a diagram for explaining another configuration of the fixing device according to the embodiment of the present invention.
FIG. 10 is a diagram showing a partially modified example of the configuration shown in FIG. 9;
[Explanation of symbols]
1 Image forming apparatus
11 Fixing device
11A First fixing member
11B Second fixing member
12A heat source
13,23,23 'Heat recovery member
13A resistor element
14,25 Heat supply member
24 Voltage stabilizer
26 Radiation fins as forced cooling means
27 Heat exchanger as forced cooling means

Claims (20)

In a fixing device including first and second fixing members opposed to each other at a fixing position of a recording material carrying an unfixed toner image,
One of the fixing members includes a heat source that heats the fixing member, a heat recovery member that contacts the fixing member and recovers residual heat of the fixing member after fixing, and the fixing member before the recovered heat is heated by the heat source. Wherein the heat recovery member and the heat supply member are in contact with each other according to the surface configuration of the fixing member. The fixing device according to claim 1,
The fixing device according to claim 1, wherein one of the fixing members has a curved surface. The fixing device according to claim 1,
The fixing device according to claim 1, wherein the heat recovery member has a configuration that can be bent along a surface of the fixing member. The fixing device according to claim 1,
One of the fixing members is constituted by a belt, and the heat recovery member is constituted by a flexible sheet. The fixing device according to claim 1,
One of the fixing members is constituted by a roller having a built-in heat source, the heat recovery member is located near the outer periphery of the fixing member, and the heat supply member is arranged in contact with the outer periphery of the fixing member. A fixing device. The fixing device according to claim 1, wherein
The fixing device according to claim 1, wherein the heat supply member is made of a heat conductor having a surface in contact with the heat recovery member and the fixing member. The fixing device according to claim 1,
A fixing device, wherein the heat recovery member and the heat supply member are configured to set the amount of heat to be supplied by using an electromotive force generated in response to the recovered heat. The fixing device according to claim 7,
A fixing device characterized in that a member capable of utilizing a thermoelectric effect such as a Seebeck effect or a Peltier effect is used as the heat recovery member and the heat supply member. The fixing device according to claim 1, wherein
The heat recovery member is provided in the vicinity of the fixing member, the heat supply member is provided in contact with the fixing member, and the heat is generated by an electromotive force generated in response to the heat recovered in the heat recovery unit. A fixing device having a configuration for causing a supply member to generate heat. The fixing device according to claim 9,
The fixing device, wherein the heat recovery member is located at least above the fixing member. The fixing device according to claim 7, wherein
The fixing device, wherein the heat recovery member forms a contact surface by arranging the resistor elements in a state of being spread over a predetermined area. The fixing device according to claim 11,
The fixing device according to claim 1, wherein the register element is repeatedly and repeatedly folded within a predetermined area. The fixing device according to claim 11, wherein
The fixing device is characterized in that the above-mentioned register element has a sandwich structure in which thin films are located on both front and back surfaces. The fixing device according to claim 11, wherein
A fixing device, wherein a plurality of the above-mentioned register elements are arranged in parallel. The fixing device according to claim 11, wherein
A fixing device according to claim 1, wherein said register element can be independently turned on and off. The fixing device according to claim 15,
The fixing device according to claim 1, wherein the barrel is capable of being turned on and off based on a predetermined temperature. The fixing device according to claim 11, wherein
The fixing device according to claim 1, wherein an arrangement interval of the register elements within a predetermined area is 0.01 to 5 mm. The fixing device according to any one of claims 7 or 8, and 11 to 16,
A fixing device, wherein an electromotive force corresponding to heat recovered by the heat recovery member is applied to a heat supply member adjusted to a voltage corresponding to a heat amount corresponding to supply heat amount control. The fixing device according to claim 9, wherein
A fixing device, wherein the heat recovery member is provided with a forced cooling unit. An image forming apparatus using the fixing device according to claim 1.

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