JP2006251654A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device having a mechanism by which thermal resistance is hard to be lowered. <P>SOLUTION: In the fixing device which fixes an unfixed toner image on a recording medium which carries the unfixed toner image by applying heat and pressure to the recording medium, it has a heater having a built-in heating source, a pressurizer pressure welded to the heater and by which the heat and the pressure are applied to the recording medium by passage of the recording medium between the pressurizer and the heater and a heat insulation cover which covers the heater and/or the pressurizer and has a heat reflection layer for reflecting radiant heat from the heater and/or the pressurizer, a first heat insulation layer for covering the heat reflection layer and a second heat insulation layer having thermal resistance lower than the thermal resistance of the first heat insulation layer for covering the first insulation layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fixing device for fixing an unfixed toner image on a recording medium by applying heat and pressure to the recording medium carrying the unfixed toner image.

In recent years, with the spread of computers, image forming apparatuses centering on printers have become widespread as means for printing information created on computers on paper. Technology related to elements is also widespread. Many of these image forming apparatuses include a fixing device that generates heat, and the toner image on the paper is fixed using the heat. Since such a fixing device generates heat, it tends to be expensive. For this reason, in order to increase the heat retaining property inside the fixing device where the toner image is fixed and prevent heat diffusion, a heat insulating cover surrounding the fixing device is conventionally provided. Among such heat insulating covers, by using a vacuum heat insulating material configured by vacuum-sealing a base material such as glass fiber having a low thermal conductivity in a bag of a laminated film, as a material constituting the inside of the heat insulating cover, A device for improving the heat insulating property of the heat insulating cover has been proposed (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2003-271044

  Generally, the fixing device is provided with a heating roll having a built-in heating source, and the surface temperature of the heating roll is as high as 160 to 200 ° C. In order to prevent the heat insulating cover from being heated excessively by such a high temperature, a metal heat reflecting plate that reflects heat is often used on the surface of the heat insulating cover on the heating roll side. Even when such a heat reflecting plate is used, the temperature of the surface of the heat reflecting plate on the side opposite to the heating roll may rise to about 130 ° C. On the other hand, since the heat resistant temperature of the layer (so-called gas barrier layer) encapsulating the base material in the vacuum heat insulating material is 100 to 120 ° C., such a heat reflecting plate and the vacuum heat insulating material described in Patent Document 1 are used. Even if the heat insulating cover is configured in combination, it is difficult to keep the heat resistance for a long time.

  In view of the above circumstances, an object of the present invention is to provide a fixing device having high heat resistance.

In order to achieve the above object, the fixing device of the present invention comprises:
In a fixing device for fixing the unfixed toner image on the recording medium by applying heat and pressure to the recording medium carrying the unfixed toner image,
Heating roll with built-in heating source,
A pressurizer that presses against the heating roll and applies heat and pressure to the recording medium by passing the recording medium between the heating roll, and a heat insulating cover that covers the heating roll and / or the pressurizer. The heat reflecting layer that reflects the radiant heat from the heating roll and / or the pressurizer, the first heat insulating layer that covers the heat reflecting layer, and the heat resistance of the first heat insulating layer that covers the first heat insulating layer The heat insulation cover which has the 2nd heat insulation layer which has heat resistance lower than the property is provided.

  Since the fixing device of the present invention has a layer structure in which two types of layers covering the heat reflecting layer overlap in order of increasing heat resistance, the layer directly covering the heat reflecting layer includes a layer having excellent heat resistance. A layer having poor heat resistance is provided on the outside, and a material having excellent heat insulation but low heat resistance can be applied, and the heat insulation cover as a whole maintains high heat resistance while maintaining heat insulation effect.

  In the fixing device of the present invention, the form “the heat reflection layer is made of a metal plate” is a preferable form.

  Since the metal plate has a remarkable property of reflecting heat, the heat insulating property of the fixing device of the present invention can be improved by using the metal plate as a material constituting the heat reflecting layer.

  In the fixing device of the present invention, “the first heat insulating layer includes a spacer that maintains a gap between the heat reflecting layer and the second heat insulating layer, and a gas that exists in the gap maintained by the spacer. The form of “consisting of” is also a preferable form.

  With such a fixing device, the portion in direct contact with the heat reflecting layer becomes a gas present in the gap and the gap held by the spacer, so that heat from the heat reflecting layer is transmitted to the second heat insulating layer. The main part is limited to the surface where the spacer is in contact with the second heat insulating layer, and the heat resistance of the fixing device of the present invention can be enhanced.

  Further, in the fixing device of the present invention, “a spacer in which the first heat insulating layer is formed integrally with the heat reflecting layer and maintaining a gap between the heat reflecting layer and the second heat insulating layer; A form of “consisting of air existing in a gap maintained by the spacer” is also a preferable form.

  In general, since air has a large heat insulating effect, in the fixing device of the present invention, the heat insulation of the fixing device of the present invention can be improved by using the air in the gap maintained by the spacer as a heat insulating material. In addition, the manufacturing cost can be reduced by providing a configuration in which the heat reflecting layer and the spacer are integrated.

  In the fixing device of the present invention, a form in which “the first heat insulating layer is a heat insulating sheet attached on the heat reflecting layer” is also a preferable form.

  Since the first heat insulating layer obtained by simply sticking the heat insulating sheet on the heat reflecting layer is a heat insulating layer that can be easily manufactured, the manufacturing cost of the fixing device of the present invention can be reduced.

  In the fixing device of the present invention, a form in which “the second heat insulating layer is a vacuum heat insulating material formed by vacuum-sealing a base body in a laminated film bag” is also a preferable form.

  The vacuum heat insulating material has an excellent heat insulating effect among heat insulating materials, and in the fixing device of the present invention, by adopting this vacuum heat insulating material as a material for the second heat insulating layer constituting the heat insulating cover, The heat insulating property of the fixing device of the present invention can be enhanced.

  According to the fixing device of the present invention, even if a heat insulating material having a low heat resistance temperature is used as the heat insulating material for the fixing device, a fixing device having high heat resistance and a large heat insulating effect as a whole can be realized.

[First Embodiment]
Hereinafter, a first embodiment of the fixing device of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view of the fixing device of the present embodiment.

  As shown in the figure, the fixing device 10 according to the present embodiment is roughly divided into a heater 11 that generates heat to fix the toner on the paper and a heater 11 that applies pressure to the paper. The pressure device 14 includes a heat insulating cover 20 that surrounds the heater 11 and the pressure device 14 and prevents heat generated from the heater 11 from diffusing outside.

  In the heater 11, heat is generated by the heater 12, and this heat is transmitted to a substantially cylindrical heating roll 110 that surrounds the heater 12, and this heat is used for toner fixing on the paper. FIG. 1 shows a cross section of the cylindrical heating roll 110. The cylindrical inner surface of the heating roll 110 is an aluminum cored bar 111, and an elastic layer 112 made of an elastic material is overlaid on the cored bar 111. Further, the outer surface of the elastic layer 112 is covered with toner. A release layer 113 is provided to make it easier to separate from the heating roll.

  The pressurizer 14 has a configuration in which an endless belt 141 surrounds the belt guide 143 attached to the support 142 and the pressing portion 13.

  As shown in the drawing, the heat insulating cover 20 is provided around the heater 11 and the pressure device 14, respectively, and an unfixed toner image 301 is used by utilizing a gap between the two heat insulating covers 20. The sheet 30 having the above is conveyed into the fixing device 10 from the right side of the figure.

  In the fixing device 10, the pressing portion 13 is pressed against the heating roll 110 via the endless belt 141 to form a nip, and in this state, the heating roll 110 rotates in the direction indicated by the arrow B in FIG. The endless belt 141 rotates around the support 142, the pressing portion 13, and the belt guide 143 in the direction indicated by the arrow A in the drawing. The sheet 30 conveyed into the fixing device 10 from the right side of the drawing receives heat and pressure between the heating roll 110 and the endless belt 141, thereby fixing the unfixed toner image 301. As shown by an arrow D in the figure, the sheet passes through the gap between the heat insulating covers 20 and is conveyed to the outside of the fixing device 10 from the left side of the figure.

  In the fixing device 10, the heating roll 110 is a roll having a total length of 330 mm and a shaft diameter of 26φ, the thickness of the release layer 113 is 60 μm, and the thickness of the cored bar 111 is 1.6 mm. The heater 12 is a 1.1 kW halogen heater, and by operating the heater 12, heat is supplied so that the temperature of the surface of the heater 11 is maintained at 160 ° C. The endless belt 141 has a belt width (the width of the endless belt 141 in the direction perpendicular to the drawing) of 344 mm, and surrounds the support 142, the pressing portion 13 and the belt guide 143 in a substantially circumferential shape. The shaft diameter is 30 mm. The endless belt 141 has a thickness of 80 μm.

  The heat insulating cover 20 is formed of a steel plate having a thermal conductivity of 80 W / mK and a thickness of 0.2 mm on the side directly facing the heater 11 and the pressurizer 14, and heat for reflecting the heat generated from the heater 11. A reflective layer 21a is provided. In general, since a metal plate such as a steel plate has a remarkable property of reflecting heat, the heat insulating property of the fixing device 10 can be improved by using the metal plate as a material constituting the heat reflecting layer. Further, the outer surface of the heat reflecting layer 21a is integrally formed with the heat reflecting layer 21a, and has a height of 1. mm extending in parallel with the length direction of the roll of the heater 11 (direction perpendicular to the sectional view of FIG. 1). A plurality of 5 mm ribs 211 are arranged in a concavo-convex shape, and as shown in FIG. 1, the base 23 </ b> B is vacuum-sealed in a bag of a laminated film 23 </ b> A on the leading ends of these ribs 211. The layers made of the vacuum heat insulating material 23 (thermal conductivity 0.01 W / mk, thickness 4.0 mm) are overlapped.

  2 is an external perspective view showing the heat reflecting layer having ribs on the outer surface extracted from the fixing device shown in FIG.

  As shown in FIG. 2, the outer surface of the heat reflecting layer 21 a has an uneven shape due to the ribs 211 arranged at equal intervals. The plurality of ribs 211 are formed integrally with the heat reflecting layer 21a by pressing a steel plate.

  As shown in the cross-sectional view of FIG. 1, a layer made of the vacuum heat insulating material 23 is overlaid on these ribs 211, and as a result, the surface where the vacuum heat insulating material 23 contacts the heat reflecting layer 21 a is Limited to the vicinity of the tip. The heat-resistant temperature of the vacuum heat insulating material 23 is 100 to 120 ° C, while the surface temperature of the heat reflecting layer 21a may rise to 130 ° C. Thus, the rib 211 is provided on the heat reflecting layer 21a, A fixing device having high heat resistance is realized by reducing the contact area between the vacuum heat insulating material 23 and the heat reflecting layer 21a.

  In the fixing device 10 shown in FIG. 1, the space surrounded by the adjacent ribs 211 and the vacuum heat insulating material 23 is filled with air 22. Since air has a large heat insulation effect, the heat insulation of the fixing device 10 can be enhanced by filling the space inside the heat insulation cover 20 with air.

  In the above description, the layer composed of the ribs 211 and the air 22 constitutes an example of the first heat insulating layer referred to in the present invention, and the layer of the vacuum heat insulating material 23 corresponds to the second heat insulating layer referred to in the present invention. It corresponds to an example.

  Furthermore, a cover layer 24 that covers the vacuum heat insulating material 23 is provided outside the vacuum heat insulating material 23. The cover layer 24 is made of heat-resistant polycarbonate mixed with 10% of glass, and its thermal conductivity is 0.2 W / mK. The cover layer 24 enhances the heat insulating effect and also plays a role of protecting the heat insulating cover 20.

The above is the description of the first embodiment.
[Second Embodiment]
The second embodiment of the fixing device of the present invention will be described below.

  The fixing device of the second embodiment is a fixing device using a heat reflecting layer having convex pins instead of the heat reflecting layer 21a having ribs 211 shown in FIG. 1 and FIG. The configuration of each unit other than the layers is the same as the configuration of each unit of the fixing device 10 described in the first embodiment. For this reason, the overlapping description about these structures is abbreviate | omitted here, and it demonstrates focusing on the structure of the outer surface of a heat | fever reflection layer.

  FIG. 3 is an external perspective view showing a heat reflecting layer having convex pins.

  The heat reflection layer 21b shown in FIG. 3 includes a plurality of convex pins 212 on the outer surface thereof, and the plurality of pins 212 are formed integrally with the heat reflection layer 21b by pressing a steel plate. Yes. As the material of the heat reflecting layer 21b and the pin 212, the same steel plate as the rigid plate used in the heat reflecting layer 21a shown in FIGS. 1 and 2 is used.

  A layer made of the vacuum heat insulating material 23 shown in FIG. 1 overlaps the pin 212 shown in FIG. 3, so that the surface where the vacuum heat insulating material 23 comes into contact with the heat reflecting layer 21 b is limited to the tip of the pin 212. . As a result, like the first embodiment, the fixing device of the second embodiment can reduce the contact area between the vacuum heat insulating material 23 and the heat reflecting layer 21b, and realize a fixing device having high heat resistance. Is done. Further, the space formed between the vacuum heat insulating material 23 supported by the plurality of pins 212 and the heat reflecting layer 21b contains air having a high heat insulating effect, and as a result, the heat insulating property of the fixing device. Will improve.

  In the second embodiment, the layer composed of the pin 212 and the air 22 constitutes an example of the first heat insulating layer referred to in the present invention.

The above is the description of the second embodiment.
[Third Embodiment]
Hereinafter, a fixing device according to a third embodiment of the present invention will be described.

  The fixing device according to the third embodiment is a fixing device in which a flocking seal, which is a kind of heat insulating sheet, is attached to the outer surface of a heat reflecting layer. The fixing device of the third embodiment is different from the fixing device 10 described in the first embodiment in that the layer composed of the rib 211 and air shown in FIGS. 1 and 2 is replaced with the layer of the flocked seal. It is a point. The configuration of each unit other than this point is the same as the configuration of each unit of the fixing device 10 described in the first embodiment. For this reason, the duplication description about these structures is abbreviate | omitted here and the flocking seal | sticker currently affixed on the outer surface of a heat | fever reflection layer is demonstrated.

  FIG. 4 is an external perspective view showing a flocked seal stuck on the outer surface of the heat reflecting layer.

  The heat reflecting layer 21c shown in FIG. 4 has a flocked seal 213 attached on the outer surface thereof. The flocked seal used in the third embodiment is a heat-resistant flocked seal VHN-90HR manufactured by Dainippon Ink Industries, Ltd., and is a flocked seal excellent in heat resistance that can be used even at high temperatures near the fixing device. The hair seal 213 is filled with heat-resistant artificial hair 214. The layer made of the vacuum heat insulating material 23 shown in FIG. 1 overlaps with such heat-resistant artificial hair 214, thereby preventing the vacuum heat insulating material 23 from coming into direct contact with the heat reflecting layer 21c. . As a result, as in the first embodiment, the fixing device of the third embodiment prevents heat from being directly transferred from the heat reflecting layer 21c to the vacuum heat insulating material 23, thereby realizing a fixing device having high heat resistance. The

  In the third embodiment, the layer of the flocked seal 213 corresponds to an example of the first heat insulating layer according to the present invention.

The above is the description of the third embodiment.
[Summary]
Finally, in each of the fixing devices of the first to third embodiments described above, the results of measuring the power consumption, the average temperature of the inner surface of the vacuum heat insulating material, and the average temperature of the outer surface of the cover layer are as follows. A fixing device having a structure in which a layer made of a vacuum heat insulating material overlaps the entire outer surface of the heat reflection layer will be described with reference to a comparative example. The fixing device of this comparative example corresponds to a fixing device in which the rib 211 and the air layer in FIG. 1 do not exist and the layer made of the vacuum heat insulating material directly overlaps the entire outer surface of the heat reflecting layer.

  FIG. 5 is a diagram illustrating measurement results of power consumption and temperature performed in each of the fixing devices of the first to third embodiments and the fixing device of the comparative example.

  As shown in the figure, the fixing device of the comparative example consumes 64.3 W, whereas the fixing device of the first embodiment has 56.1 W, and the fixing device of the second embodiment has 53.2 W. The value is much smaller than that of a conventional fixing device.

  Further, the average temperature of the inner surface of the vacuum heat insulating material (shown as temperature 1 in the figure) is 125.8 ° C. in the comparative fixing device and exceeds the heat resistant temperature range of 100 to 120 ° C. of the vacuum heat insulating material. In contrast, in the first embodiment, 99.8 ° C., and in the fixing device of the second embodiment, 97.3 ° C., both of which are lower than the heat resistance temperature of the vacuum heat insulating material, compared with the fixing device of the comparative example, It shows that these fixing devices have high heat resistance. Further, in the case of the third embodiment, the temperature is 114.1 ° C. and has sufficient heat resistance.

  Further, the average temperature of the outer surface of the cover layer (shown as temperature 2 in the figure) is 45.7 ° C. in the first embodiment compared to 68.7 ° C. in the fixing device of the comparative example, and the fixing in the second embodiment. In the apparatus, 43.2 ° C. and in the third embodiment, 57.6 ° C., both values are low, and the fixing devices of the first to third embodiments are compared with the fixing device of the comparative example. It shows that it has high heat insulation.

  The above is the description of each embodiment of the present invention.

  In each of the fixing devices of the first to third embodiments described above, the second heat insulating layer referred to in the present invention is a layer made of a vacuum heat insulating material. The heat insulating layer may have a higher thermal conductivity than the vacuum heat insulating material but may be a cheap glass wool or a layer made of a foamed resin material.

1 is a schematic cross-sectional view of a fixing device according to an embodiment. FIG. 2 is an external perspective view showing a heat reflecting layer having ribs on an outer surface extracted from the fixing device shown in FIG. 1. It is an external appearance perspective view showing the heat | fever reflection layer which has a convex pin. It is an external appearance perspective view showing the flock seal stuck on the outer surface of a heat reflective layer. It is a figure showing the measurement result of the power consumption and temperature which were performed in each fixing device of 1st Embodiment-3rd Embodiment, and the fixing device of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixing device 11 Heater 12 Heater 13 Pressure pad 14 Pressurizer 20 Heat insulation cover 23A Laminated film 23B Base | substrate 23B
23 vacuum heat insulating material 21a heat reflection layer 211 rib 24 cover layer 21b heat reflection layer 212 pin 21c heat reflection layer 213 flocking seal 214 artificial hair

Claims (6)

In a fixing device for fixing the unfixed toner image on the recording medium by applying heat and pressure to the recording medium carrying the unfixed toner image,
Heating roll with built-in heating source,
A pressurizer that presses against the heating roll and applies heat and pressure to the recording medium by passing the recording medium between the heating roll, and a heat insulating cover that covers the heating roll and / or the pressurizer. The heat reflecting layer that reflects radiant heat from the heating roll and / or the pressurizer, the first heat insulating layer that covers the heat reflecting layer, and the first heat insulating layer that covers the first heat insulating layer And a second heat insulating layer having a heat resistance lower than the heat resistance of the fixing device.   The fixing device according to claim 1, wherein the heat reflecting layer is made of a metal plate.   The first heat insulating layer is composed of a spacer that keeps a gap between the heat reflecting layer and the second heat insulating layer, and a gas that is present in the gap kept by the spacer. The fixing device according to claim 1.   The first heat insulating layer is formed integrally with the heat reflecting layer, and there is a spacer that maintains a gap between the heat reflecting layer and the second heat insulating layer, and a gap that is maintained by the spacer. The fixing device according to claim 1, wherein the fixing device comprises air.   The fixing device according to claim 1, wherein the first heat insulating layer is a heat insulating sheet attached to the heat reflecting layer.   2. The fixing device according to claim 1, wherein the second heat insulating layer is a vacuum heat insulating material in which a base body is vacuum-sealed in a laminated film bag.

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