JP2007233405A - Heat roller and fixing apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a heat roller containing a planar heat-emitting body and improving heat efficiency, and to provide a fixing apparatus that uses the heat roller. <P>SOLUTION: The heat roller is provided with a cylindrical planar heat-emitting body, in which a resistance member is imbedded in an insulating member. The planar heat-emitting body is installed between the inner tube and the outer tube. The resistance member is formed so that heat-emitting density of the planar heat-emitting body is varied in the axial direction of the heat roller. In the axial direction, the heat-emitting density of the planar heat-emitting body is greater in the central part than in the end parts. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat roller and a fixing device using the heat roller. In particular, the present invention relates to a heat roller suitable for use in, for example, a fixing device used in an electrophotographic apparatus, and a fixing device including the heat roller.

  An electrophotographic apparatus (such as a copying machine, a facsimile machine, and a printer) includes an image forming apparatus and a fixing device for fixing an image formed by the image forming apparatus and transferred onto a sheet. The fixing device includes a heat roller.

  The heat roller is composed of a metal ring, rubber covering the metal ring, and a halogen lamp arranged inside the metal ring. However, the halogen lamp has low thermal efficiency, and the rubber covering the metal ring further reduces the thermal efficiency. In addition, it takes several tens of seconds to several minutes to reach a predetermined temperature, and preheating is necessary during standby.

  Recently, a direct heating type heat roller including a planar heating element in which a resistance member is embedded in an insulating member has been developed. In this heat roller, when a current is passed through the resistance member, the resistance member generates heat and conducts heat, so that the heat efficiency is high. The planar heating element is initially formed as a flat heating element sheet, and the heating element sheet is rounded into a cylindrical shape to form a cylindrical planar heating element. Since the sheet heating element cannot maintain the cylindrical shape as it is, it is used by being attached to the inner surface of a metal cylindrical tube. However, it is difficult to attach the planar heating element to the inner surface of the cylindrical tube.

  Therefore, a method of manufacturing a heat roller has been proposed in which a cylindrical sheet heating element is sandwiched between double tubes composed of an inner tube and an outer tube. First, an inner tube is disposed on the inner surface side of a cylindrical sheet heating element, and an outer tube is disposed on the outer surface side of the heating element. Then, when a pressurized fluid is supplied to the inner tube and the inner tube and the planar heating element are expanded toward the outer tube, the planar heating element comes into close contact with the inner and outer tubes. In this manufacturing method, the planar heating element and the inner tube and the planar heating element and the outer tube do not have to be in close contact with each other at first, so that the assembling work is simple.

  It has been demanded to further improve the heat roller including such a planar heating element to improve the thermal efficiency.

  An object of the present invention is to provide a heat roller that includes a sheet heating element and can improve thermal efficiency, and a fixing device using the heat roller.

  The heat roller according to the present invention is in close contact with a cylindrical planar heating element in which a resistance member is embedded in an insulating member, an inner tube that is in close contact with the inner surface of the planar heating element, and an outer surface of the planar heating element. The resistance member is formed such that the heat generation density of the planar heating element changes in the axial direction of the heat roller.

  In this configuration, the heat generated by the planar heating element is transmitted to the medium via the outer tube. The resistance member of the planar heating element is formed in, for example, a meandering pattern, and the resistance member pattern directly affects the temperature of the outer tube and causes temperature unevenness of the outer tube. In particular, since the difference between the temperature at the end of the outer tube and the temperature at the center of the outer tube is increased, the heat generation density of the planar heating element is changed so as to change with respect to the axial direction of the heat roller. The temperature unevenness of the outer tube can be reduced.

  A fuse is formed in a part of the resistance member. A temperature sensor is provided in the same layer as the resistance member.

  The planar heating element includes a plurality of resistance members connected in parallel.

  The heat roller of the present invention includes a first cylindrical planar heating element in which a first resistance member is embedded in an insulating member, and a first closely contacting the inner surface of the first planar heating element. A tube, a second tube that is in close contact with the outer surface of the first planar heating element, and a second cylinder that is in close contact with the outer surface of the second tube and in which the second resistance member is embedded in an insulator A sheet-like planar heating element and a third tube in close contact with the outer surface of the second planar heating element, and at least one of the first and second resistance members is a heat generation density of the planar heating element Is formed so as to change in the axial direction of the heat roller.

  The fixing device of the present invention includes a heat roller having the above-described configuration and a pressure roller pressed against the heat roller, and performs fixing at a pressure contact portion between the heat roller and the pressure roller. Features.

  Further, the fixing device of the present invention includes a heat roller having the above-described configuration, a fixing roller, a belt stretched between the heat roller and the fixing roller, and the fixing roller via the belt. A pressure roller in pressure contact, and fixing is performed at a pressure contact portion between the belt and the pressure roller.

  The fixing device according to the present invention includes a first heat roller having the above-described configuration, a fixing roller, a belt stretched between the first heat roller and the fixing roller, and the belt. And a second heat roller pressed against the fixing roller, and fixing is performed at a pressure contact portion between the belt and the second heat roller.

  In the heat roller of the present invention, it is possible to supply heat that is always stable and has little temperature unevenness even during high-speed rotation. The degree of freedom of the outer diameter of the outer tube of the heat roller is high and can be made smaller than a heat roller using a halogen lamp. It has a fuse function in case of abnormal heating, and power supply input can be cut off immediately when abnormal. The temperature can be measured with a temperature sensor built in the sheet heating element without newly arranging a temperature measurement component. The temperature distribution in the heat generation region is uniform, and the temperature unevenness can be minimized.

  The present invention will be described below with reference to embodiments shown in the accompanying drawings.

  FIG. 1 is a side view showing an embodiment of a fixing device including a heat roller of the present invention. The fixing device 10 includes a heat roller 12 and a rubber-coated pressure roller 14 that is in pressure contact with the heat roller 12. The paper 16 is conveyed between the heat roller 12 and the pressure roller 14, and the toner carried on the paper 16 is melted by the heat generated by the heat roller 12, and between the heat roller 12 and the pressure roller 14. Pressurized and fixed.

  FIG. 2 is a sectional view showing the heat roller 12 of FIG. The heat roller 12 includes a cylindrical sheet heating element 26, an inner tube 28 that is in close contact with the inner surface of the sheet heating element 26, and an outer tube 30 that is in close contact with the outer surface of the sheet heating element 26.

  FIG. 3 is a sectional view showing the heat roller 12 taken along line III-III in FIG. The sheet heating element 26 includes a heating element sheet 26a in which a resistance member 32 is embedded in insulating members 34 and 36. The resistance member 32 is formed on the insulating member 34 and covered with the insulating member 36. For example, the insulating members 34 and 36 are made of a polyimide heat resistant resin, and the resistance member 32 is made of stainless steel. The heating element sheet 26a is made as a flat sheet, rounded and joined at both ends of the sheet to form a cylindrical sheet heating element 26. The inner tube 28 is made of a relatively soft aluminum material so as to be easily deformed, and the outer tube 30 is made of a relatively hard aluminum material so that the heat roller 12 maintains a cylindrical shape. For example, the inner pipe 28 is made of pure aluminum (JIS name 1050, linear expansion coefficient 23.6), and the outer pipe 30 is made of Al-Mg-Si (JIS name 6063, linear expansion coefficient 24.4). The outer tube 30 is made of a material that is stronger than the inner tube 28.

  FIG. 4 is a plan view showing a pattern of the resistance member 32 on the insulating member 34 of the heating element sheet 26a. The resistance member 32 is formed on the insulating member 34 so as to meander. An insulating member 36 is laminated on the insulating member 34 on which the resistance member 32 is formed. By causing a current to flow through both ends of the resistance member 32, the resistance member 32 generates heat, and the generated heat is transmitted to the paper 16 via the outer tube 30.

The heat roller 12 including the planar heating element 26, the inner tube 28, and the outer tube 30 is manufactured by a tube expansion method using a tube expansion outer shape and fluid pressure. First, the inner tube 28 is disposed inside the cylindrical sheet heating element 26 and the outer tube 30 is disposed outside the sheet heating element 26 to form a heat roller assembly. At this time, there may be a gap between the sheet heating element 26 and the inner tube 28, and there may be a gap between the sheet heating element 26 and the outer tube 30. Can be easily performed. Next, the heat roller assembly is inserted into the outer shape for expanding the tube, and a pressurized fluid (for example, water) is supplied into the inner tube 28 at a pressure of 60 kg / cm ² . Then, the inner tube 28 expands, the inner tube 28 closely contacts the sheet heating element 26 and expands the sheet heating element 26, and the sheet heating element 26 contacts the outer tube 30 and expands the outer tube 30. . Expansion of the outer tube 30 is limited by the outer shape for tube expansion. In this way, the inner tube 28 is in close contact with the sheet heating element 26, and the sheet heating element 26 is in close contact with the outer tube 30.

  FIG. 5 is a partial cross-sectional front view showing an example of the heat roller 12. In FIG. 5, in the heat roller 12, the length of the outer tube 30 is smaller than the length of the inner tube 28.

  FIG. 6 is a front view showing an electrode attached to the heat roller 12 of FIG. The outer tube 30 of the heat roller 12 is supported by a support member 38. A terminal portion extending from the resistance member 32 of the planar heating element 26 of the heat roller 12 is connected to the power supply member 40. Reference numeral 40a denotes a lead wire.

  FIG. 7 shows the area of the sheet heating element 26 of the heat roller 12 according to the present invention, and FIGS. 8 and 9 show the pattern of the resistance member 32 of the sheet heating element 26 of the heat roller 12. FIG. 8 is a partially enlarged sectional view of the planar heating element 26 shown in FIG.

  In FIG. 7, the planar heating element 26 is divided into a region A located at both ends, a region B located inside the region A, and a region C located in the center. 8 and 9, the pattern of the resistance member 32 of the planar heating element 26 is set so that the heat generation density in the region A is the highest, the heat generation density in the region B is the next highest, and the heat generation density in the region C is low. ing.

For example, the heat generation density in region A is 7.2 W / cm ² , the heat generation density in region B is 5.4 W / cm ² , and the heat generation density in region C is 4.54 W / cm ² . The line width of the resistance member 32 in the region A is formed with 1.46 mm, the line width of the resistance member 32 in the region B is formed with 1.46 mm, and the line width of the resistance member 32 in the region C is formed with 2.03 mm. ing. The resistance member 32 is made of stainless steel.

FIG. 10 is a view showing the temperature distribution of Sample 1 of the comparative example in which the heat generation density of the pattern of the resistance member of the planar heating element is uniform. In this example, the total calorific value of the 330 mm × 61 mm pattern area was set to 1076 W (heat generation density 5.4 W / cm ² ). As shown in FIG. 10, the temperature at the end of the outer tube 30 is extremely lowered as compared with the temperature at the center of the outer tube 30.

  FIG. 11 is a diagram showing the temperature distribution of Sample 2 in which the heat generation density of the pattern of the resistance member 32 of the planar heating element 26 varies. The heat generation density of the resistance member 32 of the planar heating element 26 is the same as that described with reference to FIGS. The total amount of heat generated in the pattern area is the same as that described with reference to FIG. As can be seen from FIG. 11, the temperature at the end of the outer tube 30 reached a peak, and the temperature at the center of the outer tube 30 slightly decreased from the peak value. The temperature distribution of the outer tube 30 as a whole was considerably averaged.

  In both sample 1 and sample 2 of the heat roller 12, the length of the outer tube 30 is 380 mm, the length of the inner tube 28 is 340 mm, and the thicknesses of the inner tube 28 and the outer tube 30 are all 0.5 mm. These samples were energized, and the temperature distribution with respect to the distance in the length direction of the heat roller 12 when the position of the heat roller 12 reached 160 ° C. was measured. 10 and 11 show this result.

The maximum temperature and the minimum temperature of the outer tube 30 are as follows. (Unit: ° C)
Maximum temperature Minimum temperature Rise time (s)
Sample 1 159.5 ℃ 101.6 ℃ 14.3
Sample 2 161.6 ℃ 144.8 ℃ 14.7
From this result, although the temperature unevenness of 57.9 ° C. occurred in the sample 1 of the comparative example, the temperature unevenness of 16.8 ° C. could be reduced in the sample 2 of the present invention.

  As described above, according to the present invention, by changing the heat generation density of the pattern of the resistance member 32 of the planar heating element 26, the temperature unevenness on the surface of the outer tube 30 is reduced without sacrificing the temperature increase time. We were able to.

  FIG. 12 is a view showing another example of the pattern of the resistance member 32 of the sheet heating element 26 of the heat roller 12. In FIG. In the example shown in FIGS. 8 and 9, the resistance member 32 includes two patterns 32 </ b> X and 32 </ b> Y divided into the upper side and the lower side in FIG. 9. In the example shown in FIG. 12, the resistance member 32 is not divided. In FIG. 12, the planar heating element 26 is partitioned into a region A located at both ends, a region B located inside the region A, and a region C located in the center. 8 and 9, the pattern of the resistance member 32 of the planar heating element 26 is set so that the heat generation density in the region A is the highest, the heat generation density in the region B is the next highest, and the heat generation density in the region C is low. ing.

  FIG. 13 is a view showing an example in which an outer layer 42 is provided on the outer surface of the outer tube 30 of the heat roller 12. As shown in FIG. The outer layer 42 is formed by a fluororesin coating.

  FIG. 14 is a view showing another example in which an outer layer 42 is provided on the outer surface of the outer tube 30 of the heat roller 12. The outer layer 42 is made of silicone rubber. As shown in FIGS. 13 and 14, by providing the outer layer 42 on the outer surface of the outer tube 30, it is possible to cope with various combinations of the layout of the heat roller 12 in the fixing device, the nip width, and the toner to be used. Can do. In addition, by optimizing the thickness of the silicone rubber, the unevenness of the pattern of the resistance member 32 that appears on the surface of the outer tube 30 when the outer tube 30 of the double tube heat roller 12 is made thin and there is no temperature unevenness. Therefore, it is possible to shorten the heating time while ensuring the print quality.

  15 and 16 are views showing an example in which a heat-resistant filler layer is formed between the cylindrical tube and the planar heating element 26. FIG. In FIG. 15, a heat-resistant filler layer 44 for assisting adhesion is provided between the outer tube 30 and the sheet heating element 26, and a heat-resistant filler layer 46 for assisting adhesion is formed in the sheet heating element 26. And the inner pipe 28. The filler layers 44 and 46 prevent an abnormal temperature increase due to heating when there is a poor adhesion, and enables uniform and stable heat transfer.

  In FIG. 16, a heat-resistant filler layer 44 that assists adhesion is provided only between the outer tube 30 and the planar heating element 26. Further, in the configuration of FIGS. 15 and 16, an air vent hole can be formed in the inner tube 28 at an appropriate size and interval. This is a device for suppressing the generation of bubbles and improving adhesion.

  In FIG. 3, the example which changed the thickness of the heat resistant resin film of the insulating members 34 and 36 of the planar heating element 26 is shown. Since a heat resistant resin film is used as the insulating material, the film thickness can be selected. The insulation member 36 on the outer tube 30 side where heat is to be actively transmitted is thin, and the insulation member 34 on the inner tube 28 side that is loaded during the production of a double tube is thick, so that the product has high stability and heat transfer efficiency. The temperature rise time can be shortened. By controlling the thickness of the heat-resistant resin film without using complicated mechanisms and controls, a more optimal thermal design becomes possible.

  FIG. 17 is a diagram showing an example in which a fuse 48 and a temperature sensor 50 are provided on the sheet heating element 26. The fuse 48 is formed by locally reducing the volume of a part of the line of the resistance member 32 so that the fuse 48 is disconnected when an excessive current flows. The fuse 48 is formed by reducing the line width without decreasing the line height of the resistance member 32, and prevents the pattern of the resistance member 32 after the heat roller 12 is formed from becoming poor adhesion. Yes. Further, since the line width is reduced, secondary processing in the height direction is not required when creating the pattern of the resistance member 32, and the cost is reduced. Conventionally, the fuse function is provided outside the heat roller 12, but in the present invention, since the fuse 48 is formed as a part of the pattern of the resistance member 32, the resistance member 32 can be immediately applied to abnormal heating. It becomes possible to cut off the energization and the safety is greatly improved.

  FIG. 19 is a diagram showing the arrangement of the temperature sensor 50. As shown in FIG. 17 and 19, the temperature sensor 50 is made of, for example, a thermistor, and is provided in the same layer as the resistance member 32 between the insulating members 34 and 36. By forming the temperature sensor 50 in the same layer as the pattern of the resistance member 32, after forming the double pipe, it becomes a heat roller 12 with a built-in temperature sensor, and it is not necessary to use a temperature sensor newly, and the design of the device The degree of freedom is greatly improved. The problem of coating deterioration due to sliding friction with the outer peripheral surface of the heat roller when using an external temperature sensor can also be prevented.

  Further, by bringing the temperature sensor 50 closer to the resistance member 32 that is a heat source, efficient temperature control becomes possible. The external temperature sensor generally used has a sensor part attached to an elastic body, and the outer periphery is coated with a protective layer. In the present invention, an elastic body is not required, and the sensor protective layer can also be used as the insulating members 34 and 36 sandwiching the resistance member 32, which is advantageous in terms of cost, including assembly.

  FIG. 18 is a diagram showing an example in which the planar heating elements 26 are connected in parallel and are composed of a plurality of resistance members 32A and 32B. For example, in this configuration, both the heater patterns A and B are energized when a rapid temperature increase is required at power-on and a print command. If the design can secure the fixing temperature by energizing only the heater pattern A after reaching the predetermined temperature, the power consumption can be reduced.

  FIG. 20 is a diagram showing an example of the triple tube heat roller 12. As shown in FIG. The triple tube heat roller 12 includes a first cylindrical planar heating element 26X in which a resistance member 32 is embedded in the insulating members 34 and 36, and a first closely contacting the inner surface of the first planar heating element 26X. Tube (inner tube) 28X, a second tube 29 (inner tube) in close contact with the outer surface of the first planar heating element 26X, and a second cylindrical surface in close contact with the outer surface of the second tube 29 And a third tube (outer tube) 30X that is in close contact with the outer surface of the second sheet heating element 26Y. Each of the first planar heating element 26X and the second planar heating element 26Y has the same structure as the planar heating element 26 described above.

  The pattern of the resistance member 32 of the first planar heating element 26X is different from the pattern of the resistance member 32 of the second planar heating element 26Y. For example, as described with reference to FIGS. 7 to 9 and 12, the pattern C of the resistance member 32 of the second planar heating element 26Y is formed so that the heat generation density at the end portion is increased. The pattern D of the resistance member 32 of the planar heating element 26X of 1 is formed to have a uniform heat generation density. The pattern C is suitable for normal printing, and the pattern D is used as preheating for continuous printing. Therefore, only pattern C is used for printing one sheet, and both patterns C and D are used for continuous printing of a plurality of sheets. Heat loss during continuous printing is minimized, and printing is possible immediately after the paper is loaded.

  In addition, when the speed and specifications of a conventional heat roller using a halogen lamp are changed, it takes time for the thermal design and trial production period of the fixing device including the change of the light distribution of the halogen lamp. In the triple-pipe heat roller 12 of the present invention, if a sheet heating element having several types of heat generation patterns is prepared in advance, it is not necessary to make a new heat source prototype by combination, thereby reducing the trial period and cost. Connected.

  FIG. 21 is a view showing an example of a fixing device including the heat roller 12 having the planar heating element 26. As shown in FIG. The fixing device 10 includes a heat roller 12 and a pressure roller 14. In FIG. 1, the heat roller 12 is disposed above the pressure roller 14, whereas in FIG. 21, the heat roller 12 is disposed below the pressure roller 14.

  FIG. 22 is a view showing an example of a fixing device including the heat roller 12 having the planar heating element 26. As shown in FIG. The fixing device 10 includes a heat roller 12 and a heat roller 18. The heat roller 18 can have substantially the same configuration as the heat roller 12.

  The fixing device 10 shown in FIGS. 1 and 21 is used in a monochrome printer or the like, and can heat the printing surface or the back surface of the paper 16 to provide a fixing device with no waiting time. Also. The fixing device 10 shown in FIG. 22 is used in a color printer, a high-speed printer, or the like that requires a fixing heat amount, and can effectively perform fixing by simultaneously heating the printing surface and the back surface of the paper 16.

  23 and 24 are diagrams showing an example in which the heat roller 12 is used in the belt-type fixing device 10. FIG. In FIG. 23, the belt-type fixing device 10 is in pressure contact with the fixing roller 20 via the heat roller 12, the fixing roller 20, the belt 22 stretched over the heat roller 12 and the fixing roller 20, and the belt 22. And a pressure roller 24. In this case, the heat generated by the heat roller 12 is transmitted to the paper 16 via the belt 22, and the toner carried on the paper 16 is melted and pressurized by the heat generated by the heat roller 12, and fixed. Is done.

  In FIG. 24, a heat roller 25 is used instead of the pressure roller 24 of FIG. The heat roller 25 can be configured similarly to the heat roller 12.

  The belt-type fixing device 10 can shorten the temperature rising time by using the fixing endless belt 22 having a low heat capacity as a heating target, and can further shorten the temperature rising time.

  FIG. 25 is a view showing another device 70 including the heat roller 12 having the planar heating element 26. The device 70 is, for example, a large electrophotographic printer, and the heat roller 12 is used at a place other than the fixing device. In FIG. 27, there are a photosensitive drum 72 and a fixing flash lamp 74. The heat roller 12 is used as a paper moisture removing roller 76 disposed on the upstream side of the photosensitive drum 72. The heat roller 12 is used as a drum dew condensation prevention roller 78 disposed inside the photosensitive drum 72. The heat roller 12 is used as a preheat roller 80 disposed between the photosensitive drum 72 and the fixing flash lamp 74. The heat roller 12 is used as a sheet wrinkle stretching roller 82 disposed on the downstream side of the fixing flash lamp 74.

  As described above, the heat roller 12 (a) removes moisture from the paper before transfer, (b) prevents condensation on the photosensitive drum, (c) performs preheating before flash fixing, (d) after fixing. Can be used to wrinkle media. The heat roller 12 need not be used in all of the above examples. The application of the heat roller 12 is not limited to the example shown in FIG. Since the resistance value of the sheet heating element 26 can be set freely and easily, versatility other than the fixing device is enhanced.

  FIG. 26 is a diagram showing an example of power consumption of the fixing device 10 including the heat roller 12 having the planar heating element 26 and a change in the temperature of the heat roller 12. A curve P indicates power consumption, and a curve Q indicates the temperature of the heat roller 12. When a print command is received, the maximum power to raise the heat roller to the fixing temperature is applied (time point D), the input power is reduced when the fixing temperature is reached (time point E), and the power supply is stopped after printing is completed. (Time F). G indicates a printing period, and H indicates a standby period. When a printing command is input again, heating of the heat roller is started (time point I).

  FIG. 27 is a graph showing changes in power consumption and roller surface temperature when a halogen lamp is used. A curve P indicates power consumption, and a curve Q indicates the temperature of a heat roller having a halogen lamp. When a printing command is received, the maximum power for raising the heat roller to the fixing temperature is input (time point D), the input power is suppressed when the fixing temperature is reached (time point E), and the power supply is small after printing is completed. Maintain at value (time point F). G indicates a printing period, and H indicates a standby period. When a printing command is input again, heating of the heat roller is started (time point I).

  The heat roller having a halogen lamp has lower thermal efficiency than the direct heating type heat roller 12, and preheating is required to satisfy the temperature raising performance even after the printing is completed. The direct heating type heat roller 12 makes use of the advantage that it has an excellent temperature rise time, and can be controlled to reduce power consumption.

  The features of the plurality of embodiments described above can be implemented in appropriate combination.

  As described above, according to the present invention, it is possible to provide a heat roller including a planar heating element and having excellent thermal efficiency. In the heat roller of the present invention, it is possible to supply heat that is always stable and has little temperature unevenness even during high-speed rotation. The degree of freedom of the outer diameter of the outer tube of the heat roller is high and can be made smaller than a heat roller using a halogen lamp. It has a fuse function in case of abnormal heating, and power supply input can be cut off immediately when abnormal. The temperature can be measured with a temperature sensor built in the sheet heating element without newly arranging a temperature measurement component. The temperature distribution in the heat generation region is uniform, and the temperature unevenness can be minimized.

  As described above, according to the present invention, it is possible to provide a heat roller including a planar heating element and having excellent thermal efficiency. In addition, a fixing device using such a heat roller with good thermal efficiency can be provided, and can be widely used in electrophotographic devices and the like.

It is a side view showing an example of a fixing device including a heat roller of the present invention. It is sectional drawing which shows a heat roller. It is sectional drawing which shows the heat roller taken along line III-III of FIG. It is a top view which shows the pattern of the resistance member of a planar heating element. It is a partial section front view showing an example of a heat roller. It is a front view which shows the place which attaches an electrode to the heat roller of FIG. It is a figure which shows the area | region of the planar heating element of a heat roller. It is the elements on larger scale which show the pattern of the resistance member of the planar heating element of the heat roller of FIG. It is a figure which shows the pattern of the resistance member of the planar heating element of the heat roller of FIG. It is a figure which shows the temperature distribution of the sample with the uniform heat_generation | fever density of the pattern of the resistance member of a planar heating element. It is a figure which shows the temperature distribution of the sample from which the heat_generation | fever density of the pattern of the resistance member of a planar heating element changes. It is a figure which shows the other example of the pattern of the resistance member of the planar heating element of a heat roller. It is a figure which shows the example which provided the outer layer in the outer surface of the outer tube | pipe of a heat roller. It is a figure which shows the other example which provided the outer layer in the outer surface of the outer tube | pipe of a heat roller. It is a figure which shows the example which formed the heat resistant filler layer between the cylindrical tube and the planar heating element. It is a figure which shows the other example which formed the heat resistant filler layer between the cylindrical tube and the planar heating element. It is a figure which shows the example which provided the fuse and the temperature sensor in the planar heating element. It is a figure which shows the example which consists of a several resistance member by connecting a planar heating element in parallel. It is a figure which shows arrangement | positioning of a temperature sensor. It is a figure which shows the example of a triple tube heat roller. It is a figure which shows the example of the fixing device containing a heat roller. It is a figure which shows the example of the fixing device containing a heat roller. It is a figure which shows the example of the fixing device containing a heat roller. It is a figure which shows the example of the fixing device containing a heat roller. It is a figure which shows the example of the apparatus containing a heat roller. It is a figure which shows the example of the power consumption of the fixing device containing the heat roller which has a planar heating element, and the temperature change of a heat roller. It is a figure which shows the example of the power consumption of the fixing device containing the heat roller which has a halogen lamp, and the temperature change of a heat roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixing device 12, 18, 25 Heat roller 14, 24 Pressure roller 16 Paper 22 Belt 26 Planar heating element 28 Inner tube 30 Outer tube 32 Resistance member 34, 36 Insulation member 48 Fuse 50 Temperature sensor

Claims (8)

  A cylindrical planar heating element in which the resistance member is embedded in the insulating member, an inner tube in close contact with the inner surface of the planar heating element, and an outer tube in close contact with the outer surface of the planar heating element, The resistance member is formed so that a heat generation density of the planar heating element changes in an axial direction of the heat roller.   The heat roller according to claim 1, wherein a fuse is formed in a part of the resistance member.   The heat roller according to claim 1, wherein a temperature sensor is provided in the same layer as the resistance member.   The heat roller according to claim 1, wherein the planar heating element includes a plurality of resistance members connected in parallel.   A first cylindrical sheet heating element in which a first resistance member is embedded in an insulating member; a first tube closely contacting the inner surface of the first sheet heating element; and the first sheet shape. A second tube closely contacting the outer surface of the heating element, a second cylindrical planar heating element closely contacting the outer surface of the second tube, and a second resistance member embedded in an insulator; A third tube closely contacting the outer surface of the second planar heating element, and at least one of the first and second resistance members has a heat density of the planar heating element that varies in the axial direction of the heat roller. The heat roller is formed as described above.   A heat roller according to any one of claims 1 to 5 and a pressure roller pressed against the heat roller, wherein fixing is performed at a pressure contact portion between the heat roller and the pressure roller. A fixing device characterized.   The heat roller according to claim 1, a fixing roller, a belt stretched between the heat roller and the fixing roller, and pressed against the fixing roller through the belt. And a pressure roller, and fixing is performed at a pressure contact portion between the belt and the pressure roller.   The first heat roller according to any one of claims 1 to 5, a fixing roller, a belt stretched between the first heat roller and the fixing roller, and the belt via the belt. And a second heat roller in pressure contact with the fixing roller, wherein the fixing is performed at a pressure contact portion between the belt and the second heat roller.

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