JP5113410B2 - Manufacturing method of fixing belt - Google Patents

Description

The present invention relates to a method of manufacturing a fixing belts used in the fixing device for fixing by heating an unfixed toner on a recording medium in an image forming apparatus such as a copying machine or a printer.

  Conventionally, a cylindrical fixing belt is pressed against a heating roller by a pressure pad provided on the inside thereof to form a nip portion, and a recording medium on which unfixed toner is transferred is passed through the nip portion. There is known a fixing device for fixing a contact toner to a recording medium.

  In the fixing belt of this type of fixing device, when the parallelism between the heating roller and the pressing pad is not sufficient, or when there is a difference in circumferential length between both ends of the fixing belt, the fixing belt is orthogonal to the conveyance direction of the recording medium. In order to prevent the meandering, guides are provided at both ends of the fixing belt. However, when the end portion of the fixing belt hits the guide due to meandering of the fixing belt, the end portion of the fixing belt receives a reaction force from the guide. As a result, the heat-resistant sheet swells outward along the gap (winding) A between the heat-resistant sheets of the outermost layer, and the quality of the fixed image may be deteriorated.

  Further, when the fixing belt passes through the nip portion, the fixing belt warps inward, tensile stress is generated on the inner peripheral surface, and the inner winding tends to open.

  In addition, an elastic layer such as a fluororesin is provided outside the outermost layer of the fixing belt to improve releasability. However, if air remains when the elastic layer is covered, the surface of the elastic layer swells, and fixing is performed. There is a possibility of adversely affecting the image quality later.

  In order to improve the strength against buckling of the end portion caused by meandering of the fixing belt in Patent Document 1, the applicants of the present application wound a plurality of heat-resistant sheets 31A and 31B in a spiral shape as shown in FIG. The fixing belt 31 is proposed in which layers are formed and the spiral winding angles of the heat-resistant sheets 31A and 31B are different for each layer. Also, in Patent Document 2, in order to prevent image noise due to frictional static electricity between the fixing belt and the recording medium, as shown in FIG. 4, the inside is a conductive sheet 32A, and the other is an insulating sheet 32B. In addition, a fixing belt 32 is proposed in which the sheets 32A and 32B are flatly wound.

However, even with these fixing belts 31 and 32, the strength against the end buckling due to the meandering and the strength against the tension on the inner surface of the nip portion are not sufficient. Further, the residual problem of air when an elastic layer in the outermost layer of the fixing belt has not been solved yet.
JP 2004-240311 A Japanese Patent Laying-Open No. 2005-62562

Therefore, the present invention improves the strength against the buckling of the end due to the meandering of the fixing belt and the strength of the inner surface of the fixing belt at the nip, and also prevents air remaining when the outermost layer of the fixing belt is coated with the elastic layer. prevention to, and to provide a method of manufacturing a fixing belts capable of enhancing the image quality.

In order to solve the above-described problems, the present invention provides a method for manufacturing a cylindrical fixing belt in which a plurality of heat-resistant sheets are laminated and bonded together. A spiral wound layer is formed by spirally winding, a flat heat-resistant sheet is wound on the adhesive layer of the spiral wound layer to form a flat wound layer, and adhesion between the spiral wound layer and the flat wound layer The agent is cured to form a belt base material, the elastic layer tube is coated on the belt base material, fired, and contracted while removing air from the windings of the flat wound layer to form an elastic layer It consists of a process.

According to the fixing belt manufactured in accordance with the present invention, the winding of the flat wound layer provided on the outer side of the substrate is parallel to the axis of the fixing belt, so that the winding is inclined with respect to the axis of the fixing belt. Compared with a base material provided with a spiral wound layer on the outside, buckling that rises along the winding is less likely to occur when the end of the fixing belt hits the guide due to meandering of the fixing belt.

  In addition, since the winding of the spirally wound layer provided on the inner side of the substrate is oblique to the axis of the fixing belt, a flat wound layer having a winding parallel to the axis of the fixing belt is provided on the outer side. Compared to the base material formed, the winding is less likely to open due to the tensile stress generated on the inner peripheral surface when the fixing belt passes through the nip portion.

  Further, since the flat wound layer is provided on the outside of the base material, air can be easily removed along the winding of the flat wound layer when the elastic layer is coated on the flat wound layer.

  The thickness of the heat-resistant sheet forming the flat wound layer of the substrate is not more than the thickness of the heat-resistant sheet forming the spiral wound layer and not more than 50 μm, and the gap between the winding direction end faces of the flat wound layer Is preferably 0.5 mm or less.

  It is preferable to provide an elastic layer outside the flat wound layer of the substrate.

  As the heat-resistant sheet, polyimide (PI). A resin sheet selected from the group consisting of polyamide-imide (PAI), polyetherimodo (PEI), polyetheretherketone (PEEK), and polyphenylene sulfide (PPS) can be used.

  As the elastic layer, fluororesin or silicon rubber can be used.

The fixing belt manufactured according to the present invention has a base material composed of a spirally wound layer in which a heat resistant sheet is spirally wound on the inner side and a flat wound layer in which a heat resistant sheet is wound flatly on the outer side. The strength against buckling when the end portion hits the guide is improved, the strength against tensile stress generated on the inner peripheral surface when the fixing belt passes through the nip portion is improved, and the quality of the fixed image is also improved.
Further, since the kick set a flat winding layer on the outside of the substrate, when coated with an elastic layer on top of the flat-wound layer, it is possible to easily remove air along the winding th flat winding layer, processed Is easy, and the elastic layer can be formed smoothly, so that the quality of the fixed image is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1A and 1B show a fixing belt 10 manufactured by the method according to the present invention. The fixing belt 10 is cylindrical and includes an elastic layer 12 on a belt substrate 11. The belt base 11 consists of two layers, an inner side and an outer side. The inner layer is a spirally wound layer 13 obtained by spirally winding a film-like heat-resistant sheet. The outer layer is a flat wound layer 14 obtained by flatly winding a film-like heat-resistant sheet, and is adhered to the spirally wound layer 13 via an adhesive layer (not shown).

  The inner spirally wound layer 13 is formed by spirally winding an elongated heat-resistant sheet with a gap S so that the edges do not overlap each other. This is because, when the edges overlap, a step is generated by the thickness of the heat-resistant sheet, a step is also generated in the flat wound layer 14 provided thereon, and the final surface is not flat. If the gap S of the spirally wound layer 13 is too large, streaks remain, and therefore, it is preferably 0.5 mm or less from the viewpoint of the strength, surface flatness, and workability of the belt base material 11. The thickness of the heat-resistant sheet forming the spirally wound layer 13 needs to be 50 μm in terms of strength. The spiral angle of the spiral wound layer 13 (the angle in the spiral winding direction with respect to the axis of the cylindrical belt substrate) θ is arbitrary, but is preferably about 45 ° to 60 °.

  The outer flat wound layer 14 is formed by winding an elongated heat-resistant sheet so that two longitudinal edges are adjacent to each other with a gap A around the longitudinal direction. This is because when the edges overlap, a step is generated by the thickness of the heat-resistant sheet, and a step is also generated in the elastic layer provided thereon, so that the final surface is not flat. If the gap A of the flat wound layer 14 is too large, streaks remain, so that it is preferably 0.5 mm or less from the viewpoint of the strength, surface flatness, and workability of the belt substrate 11. The thickness of the heat-resistant sheet for forming the flat wound layer 14 is not more than the thickness of the heat-resistant sheet for forming the spirally wound layer 13 and not more than 50 μm, and preferably 25 μm.

  As the heat-resistant sheet for forming the spirally wound layer 13 and the flat wound layer 14, polyimide (PI). Polyamide-imide (PAI), polyetherimodo (PEI), polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and the like can be used. As the adhesive layer, perfluoroalkoxy alkane (PFA) or fluorinated ethylene propylene (FEP) can be used.

  The elastic layer 12 is coated on the belt base material 11. The thickness of the elastic layer 12 is 10 to 85 μm, preferably 30 to 50 μm, more preferably 30 μm. As the heat-resistant material for forming the elastic layer 12, fluororesin or silicon rubber can be used. The elastic layer 12 may be formed by spirally winding a heat-resistant sheet on the flat wound layer 14 of the belt base material 11 in the same manner as the spiral wound layer 13. It may be deposited on the flat wound layer 14 of the material 11. A release layer (not shown) made of, for example, a fluorine-based resin may be further formed on the elastic layer 12.

  Next, a method for manufacturing the fixing belt having the above configuration will be described. The mandrel of the belt winding machine is rotated, and the heat-resistant sheet for spiral winding having the adhesive layer applied on one side is supplied onto the mandrel so that the adhesive layer faces outward from the direction inclined with respect to the axis of the mandrel. Thereby, a heat-resistant sheet is wound helically on a mandrel, and a spiral wound layer is formed (spiral winding process). Subsequently, a flat-winding heat-resistant sheet is supplied onto the adhesive layer of the spirally wound layer from a direction orthogonal to the mandrel axis. Thereby, a flat winding layer is formed on the adhesive layer of the spiral winding layer (flat winding step). The cylindrical member on which the spirally wound layer and the flatly wound layer are formed is taken out from the mandrel and temporarily fixed, and both ends are roughly cut (temporary fixing step). The roughly cut cylindrical member is fired to cure the adhesive between the spirally wound layer and the flatly wound layer (fixing step). And this cylindrical member is cut | disconnected by arbitrary length, and it is set as a belt base material (edge part cutting process). Finally, the elastic layer tube expanded on the belt base material is coated, fired and contracted to form an elastic layer (elastic layer forming step). In this elastic layer forming step, the air between the belt base material and the elastic layer escapes outside from the winding of the flat wound layer of the belt base material. Since the winding is parallel to the axis of the belt base material, the air easily escapes to the outside, but it is preferable to forcibly suck the air as necessary.

FIG. 2 shows a fixing device 20 having a fixing belt 10 manufactured by the method according to the present invention. The fixing belt 10 is supported by the pressure pad 21 being inserted inside, and is pressed against the heating roller 22 via the pressure pad 21. The surface of the pressure pad 21 facing the heating roller 22 is concavely curved toward the center of the fixing belt 10 in order to form a nip portion 23 between the fixing belt 10 and the heating roller 22. Guides (not shown) are provided at both ends of the fixing belt 10 to restrict the meandering of the fixing belt 10. The heating roller 22 has a heater 24 inside. Instead of the heater 24, the heating roller 22 can be heated by an induction heating device. A thermistor 25 is provided close to the outer surface of the heating roller 22, and the temperature of the surface of the heating roller 22 is controlled to a predetermined temperature by controlling the heater 24 based on the temperature of the surface of the heating roller 22 detected by the thermistor 25. To be maintained. The heating roller 22 is rotationally driven in the direction of the arrow by a driving unit (not shown), and the fixing belt 10 is driven to rotate in the direction of the arrow. When the recording medium 26 on which the unfixed toner image T is transferred to the nip 23 between the heating roller 22 and the fixing belt 10 is conveyed toward the heating roller 22 side, the unfixed image on the recording medium 26 is unfixed. The toner image T is heated and pressurized to be fixed.

  When the fixing belt 10 meanders in the axial direction in FIG. 1 during operation of the fixing device 20 and hits a guide (not shown), a load acts on the end of the fixing belt 10 due to a reaction force from the guide. In general, this load causes buckling to swell in the direction perpendicular to the axis of the fixing belt 10, but if there is an oblique winding around the axis of the cylindrical fixing belt 10, Buckling occurs as it rises along the eyes. However, in the present invention, there is a flat wound layer 14 on the outer side of the belt base 11, and the winding is parallel to the axial center of the cylindrical fixing belt 10, so that the seat rises along the winding. It is hard to bend.

  Further, when the fixing belt 10 passes through the nip portion 23 during the fixing operation, the fixing belt 10 warps inward and tensile stress is generated on the inner peripheral surface, but the spirally wound layer 13 provided on the inner side of the fixing belt 10. Since the winding is oblique to the axial center of the cylindrical fixing belt 10, the winding is difficult to open due to tensile stress.

  Therefore, the fixing belt 10 of the present invention does not disturb the fixed image due to the bulge or breakage along the winding of the fixing belt 10, and can fix the image with good image quality. Further, since the strength against buckling of the outer surface of the end portion and the tension of the inner surface of the nip portion 23 is high and damage is difficult, the life of the fixing belt 10 is improved.

  The inventors conducted experiments to confirm the effect of the fixing belt of the present invention. First, as shown in Table 1, glossy paper, OHP, and plain paper are obtained by a fixing device using a fixing belt in which the thickness of the inner spiral winding layer and the outer flat winding layer and the gap A between the outer flat winding layers are variously changed. The formed solid toner image composed of yellow and magenta was fixed, and it was confirmed whether or not streaks were generated in the toner image due to the presence of the gap A in the outer flat wound layer. In Table 1, “◎” indicates that no streak was confirmed, and “◯” indicates that a streak was slightly confirmed. The sample that was ○ in the first experiment was retested. As a result, it was found that the gap between the outer flat wound layers is preferably 0.5 mm or less. Further, as in the fixing belt of Sample No. 4, when the thickness of the inner spirally wound layer is 25 μm, the belt is deformed. Therefore, it was found that the thickness of the inner spirally wound layer needs to be 50 μm in terms of strength. Further, it has been found that the outer flat wound layer is preferably 50 μm or less, preferably 25 μm. In addition, it is most suitable in terms of image quality when the thickness of the inner spiral wound layer of sample number 2 is 50 μm, the thickness of the outer flat wound layer is 25 μm, and the gap A between the outer flat wound layers is 0.5 mm. I understood.

  Next, as shown in Table 2, the fixing belts of various winding forms were run, and the travel distance when the fixing belt rotated without damage was obtained. The travel distance in Table 2 indicates the minimum value among five experiments conducted for each sample. The travel distance is expressed by the circumference of the fixing belt × the number of revolutions (km), and the target is 140 km. The inner layer was a 50 μm thick PI heat-resistant sheet, the intermediate layer was 25 μm, a PI heat resistant sheet, the outer layer was a 25 μm PI heat resistant sheet. The elastic layer of the surface layer was a 30 μm PFA tube. Sample Nos. 1 and 2 are conventional examples in which the outer layer of the fixing belt is a spirally wound layer, and Sample No. 3 shows the present invention in which the outer layer is a flat wound layer and the others are spirally wound layers. Is another embodiment of the present invention in which the outer layer is a flat wound layer and the others are spiral wound layers, and an elastic layer is provided on the flat wound layer. When the sample number 2 of the conventional example and the sample number 3 of the present invention were compared, the traveling distance was remarkably increased, and the superiority of the present invention was confirmed. In addition, when Sample No. 1 of the conventional example and Sample No. 4 of the present invention were compared, the travel distance was significantly increased by providing the elastic layer, and the superiority of the present invention was confirmed.

FIG. 2A is a front view and a cross-sectional view of a fixing belt manufactured by the method according to the present invention. FIG. 3 is a cross-sectional view of a fixing device using a fixing belt manufactured by the method according to the present invention. FIG. 9 is a front view illustrating an example of a conventional fixing belt. FIG. 10 is a front view showing another example of a conventional fixing belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixing belt 11 Belt base material 12 Elastic layer 13 Spiral winding layer 14 Flat winding layer

Claims (1)

In the manufacturing method of a cylindrical fixing belt formed by laminating and bonding a plurality of heat-resistant sheets,
A spiral wound layer is formed by spirally winding a heat-resistant sheet for spiral winding with an adhesive layer applied on one side so that the adhesive layer is on the outside,
A flat wound layer is formed by winding a flat wound heat-resistant sheet on the adhesive layer of the spiral wound layer,
The adhesive between the spiral wound layer and the flat wound layer is cured to form a belt substrate,
A method for producing a fixing belt, comprising coating a tube for an elastic layer on a belt base material, firing, and shrinking while removing air from a winding of the flat wound layer to form an elastic layer.

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