JPS6157634B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a pressure roll provided in a heating and pressure fusing device using an anti-offset liquid used in the fixing process of an electrophotographic copying device. This invention relates to a pressure roll that achieves uniform pressure distribution and complete prevention of penetration of anti-offset liquid from both ends of the roll.

As shown in FIG. 1, a conventionally known heating and pressure fusing device is mainly composed of a heating roll 1 and a pressure roll 2, and the heating roll is connected to a metal pipe 5.
A heating element 3 is provided inside the metal pipe, and the surface of the metal pipe is coated with a non-adhesive resin 4, and the thermoplastic resin powder (hereinafter referred to as toner) of the unfixed image is fused with heat and pressure. Silicone oil or the like is used as a preventive liquid to wet the surfaces of the heating roll and pressure roll.

The pressure roll has a heat-resistant and elastic deformable material 7 on a metal support shaft 6 (hereinafter referred to as roll core).
For example, mold silicone rubber (hot-flow molding)
Furthermore, a thin-walled tube 8 (hereinafter referred to as sleeve) made of non-adhesive resin is placed on the surface of the molded silicone rubber.
The silicone rubber and sleeve are glued together.

Then, a ring seal 9 is made of an oil-resistant deformable material, and the ring seals are attached with a silicone rubber adhesive to the surfaces of both ends of a pressure roll in which a deformable material such as silicone rubber is molded on the cylindrical surface of the roll core. The cylindrical surface of the ring seal and the sleeve are bonded with the same adhesive to create an oil-resistant pressure roll that deforms under pressure, and the outside of the ring seal is covered with a fixing ring 10 (made of a rigid material). For example, it is fixed with a metal ring) to form a variable pressure roll as shown in FIG.

However, with such a structure, the anti-offset liquid permeates through the bonded area between the ring seal and the roll core and the bonded area between the ring seal and the sleeve, swells the adhesive and peels off the bonded area, and eventually the anti-offset liquid is released. It has the disadvantage that it penetrates into the mold rubber inside and causes the mold rubber to swell. This also causes uneven pressure distribution and nip width across the pressure roll, as well as poor adhesion between the mold rubber and the sleeve.
It also has drawbacks such as the problem of paper wrinkles. There is also the problem that the rubber on the side surface of the ring seal that contacts the corner of the fixing ring wears out or cracks (see FIG. 2).

Further, even if a ring seal made of an oil-resistant deformable material disclosed in Japanese Patent Publication No. 47-20747 was used, swelling of the ring seal itself could be prevented, but swelling of the adhesive could not be prevented. Also, it would be better to use a non-swelling adhesive as the adhesive, but the adhesive part mentioned above is subject to high heat and strong mechanical deformation, and the adherend may be molded rubber such as silicone rubber or a metal roll core. For example, since the sleeve is made of non-adhesive tetrafluoroethylene-hexafluoropropylene copolymer resin (hereinafter referred to as EEP), an adhesive with heat resistance and high adhesiveness is, for example, RTV-108 (General・Currently, the adhesive is limited to silicone rubber adhesives such as those manufactured by Electric Silicone Products Department, and no adhesive with non-swelling properties has yet been developed. In other words, the conventional pressure roll could not prevent swelling at the end of the pressure roll.

The above has described a pressure roll with a structure having a sleeve on the molded rubber surface, but a pressure roll without a sleeve on the molded rubber surface can also be made by vulcanizing and molding silicone rubber, for example. When the obtained pressure roll is attached to a heating and pressurizing device and fixing is performed while supplying anti-offset liquid, the anti-offset liquid penetrates from both end surfaces of the roll while the pressure roll is in use, resulting in 4000
After ~5,000 copies, swelling occurred at both ends of the roll, resulting in significant changes in the outer diameter and hardness of the roll, making it impossible to achieve satisfactory fixing.

The inventor of the present invention has conducted various studies to eliminate such drawbacks in conventional pressure rolls, and has found that by preventing the offset prevention liquid from penetrating from both ends of the pressure roll, unevenness of the roll surface can be prevented. The present invention was completed by discovering that it is possible to prevent such swelling.

An object of the present invention is to provide a pressure roll that uses an anti-offset liquid and is used in the fixing process of an electrophotographic copying apparatus, in which the pressure distribution on the roll surface and the nip width are always maintained uniform. It is to be.

Another object of the present invention is to provide a pressure roll for a fixing process that uses an anti-offset liquid, in which the end portion of the roll is prevented from swelling due to the anti-offset liquid.

Generally speaking, the above purpose is to provide ring seals made of a heat-resistant, elastic, deformable material with a hardness higher than that of the molded rubber on both end sides of the molded rubber molded into the roll core. It is achieved by doing so.

Furthermore, the above-mentioned object of the present invention is to install ring seals made of a heat-resistant and elastic deformable material having higher hardness than the molded rubber molded into the roll core on both end sides of the molded rubber; This is also accomplished by providing a sheet of oil-resistant non-swelling material on the outside.

According to another preferred embodiment of the present invention, the inner surface of the ring seal (the surface facing the molded rubber)
In addition to providing an oil-resistant non-swelling sheet on the ring seal, an anti-offset liquid permeation prevention layer is provided on the outer surface of the ring seal to more fully prevent swelling of the end of the pressure roll and damage to the ring seal caused by the fixing ring. can do.

According to the present invention, the sheet of oil-resistant, non-swelling material applied to the side surface of the ring seal can be made of a thin plate such as plastic film or aluminum foil, and the portion to be joined to the roll core or sleeve is oil-resistant and non-swellable. The bonding can be carried out by gluing with a heat-resistant adhesive, such as an epoxy resin, or by a heat-sealing process. Preferably, the same type of resin is used for the plastic sheet and the sleeve.

In carrying out the present invention, the material constituting the ring seal may be any heat-resistant and elastic material, such as heat-vulcanized silicone rubber.

The ring seal used in the present invention is a heat-resistant deformable material that has a higher hardness than molded rubber, but the present invention prevents swelling of the rubber and "settling" of the rubber.
This was done based on the fact that the hardness of the rubber has a close relationship with the hardness of the rubber.

The hardness of this ring seal must be greater than the hardness of the molded rubber molded into the roll core, such as silicone rubber (for example, JIS hardness of 40°), but the difference in hardness between the ring seal and the molded rubber is approximately JIS hardness. The angle may be 5° or more, and the preferred range is 50 to 20°. The hardness of the ring seal should be greater than the hardness of the mold rubber in terms of preventing offset prevention liquid from penetrating, but in terms of roll pressure distribution and nip width, the difference in hardness from the mold rubber should be at most 20 degrees. It is desirable not to exceed it.

As a material for forming the anti-offset liquid penetration prevention layer 15 (FIG. 6), for example, a fluorine-based synthetic resin paint is used.

The pressure roll obtained in this way provides the pressure distribution and uniform nipple width on the roll surface necessary to heat-fuse and fix the unfixed toner image on the paper and obtain a good copy image. This eliminates the problem of paper wrinkles and also prevents the offset prevention liquid from penetrating, so it can be used for a long period of time.

The present invention will be specifically explained using the following reference examples and examples.

Reference example (see Figure 3) The roll 6 is made of a heat-resistant and oil-resistant rubber, such as silicone rubber 7, which swells with offset prevention liquid.
A pressure roll 1 was made by vulcanization molding, and the pressure roll thus obtained was attached to a heating and pressing device in the fixing process of an electrophotographic copying machine, and fixing was performed while supplying an anti-offset liquid. During use of the pressure roll, penetration of the anti-offset liquid progresses from both end surfaces of the roll, and after 4000 to 5000 copies, extreme swelling occurs at both ends of the roll (the part of the roll that rises from the dotted line in Figure 3). The outer diameter and hardness of the roll changed significantly, making it impossible to perform satisfactory fixing.

According to the present invention, ring seals made of a heat-resistant deformable material having a hardness higher than that of the molded rubber applied to the pressure roll are provided on both end faces of the molded rubber, thereby forming a sleeve on the surface of the pressure roll. If the pressure roll does not have one, the both ends of the pressure roll are made of high hardness ring seals, which prevents the pressure roll from expanding at the end surface, which occurs with conventional pressure rolls. The pressure distribution on the surface and the nip width are always maintained uniformly, eliminating the occurrence of paper wrinkles, etc., and when the pressure roll has a sleeve on the surface, in addition to the swelling prevention effect of the ring seal in the above case, the heating Even when used repeatedly under pressure with a roll, the ring seal itself hardly wears out, so the adhesion between the sleeve and the ring seal is maintained well, and the anti-offset liquid permeates between the sleeve and the ring seal. As a result, the effect of preventing the adhesive bonding the mold rubber and the ring seal from swelling can be obtained.

Example 1 (see Figure 4) Silicone rubber 7 is vulcanized and molded onto a metal roll core 6 using low hardness silicone rubber (rubber for heat vulcanization molding with a JIS hardness of 30 to 40 degrees), and the molded rubber 7 is obtained. A rubber ring 9a is made of the same type of silicone rubber with higher hardness, and is adhered to both ends of the molded rubber 7 with a silicone rubber adhesive to form a pressure roll as shown in Fig. 4, which is immersed in anti-offset liquid. After swelling and adjusting the outside diameter and hardness of the roll, we installed a heating and pressurizing device that uses anti-offset liquid and performed a fixing operation, and the changes in dimensions and hardness of the pressure roll were stable and uniform. A wide nip width was obtained, paper wrinkles were reduced, and copy quality was good. When a fluorinated ethylene elastomer paint (trade name: Perflon) was applied to the surface of the rubber ring 9a shown in FIG. 6, the amount of swelling at both ends of the roll could be reduced.

In this example, a pressure roll in which an anti-offset liquid is applied directly to the mold rubber surface has been described, but other embodiments of the pressure roll in which a sleeve made of non-adhesive resin is provided on the mold rubber surface have been described. The aspect will be explained below.

A pressure roll having a sleeve according to the present invention will be explained with reference to FIG. Rubber is molded on the cylindrical surface of the metal roll core 6, and a rubber ring 9a having a harder hardness than the mold rubber 7 is adhered to both end sides of the mold rubber 7 and the cylindrical surface of the roll core 6 with a silicone rubber adhesive, and a non-adhesive ring is formed around the mold rubber. The molded rubber 7 and the heat-resistant rubber ring 9a are simultaneously bonded together. The above structure is the same as that of the pressure roll, but in the case of the rubber ring 9a as shown in Fig. 5, a heat-resistant rubber elastic material is sufficient, but oil resistance is not required. Any type of rubber or elastomer or glastomer material may be used. Next, in order to cover the rubber rings 9a used as seal rings and the adhesive portions on both end side surfaces of the pressure roll having the above configuration with an oil-resistant and non-swelling material sheet 12,
The oil-resistant, non-swelling material sheet is bonded to the outer surface of the rubber ring 9a, the inner surface of the sleeve 8, and the cylindrical surface of the roll core 6 using an adhesive or heat-sealing process, and then a rigid material is attached as shown in FIG. The resulting fixing ring 10 is attached to the cylindrical surface of the non-swelling material sheet 12 corresponding to the portion covered with the roll core 6, and the fixing ring 10 is further prevented from shifting laterally with a circlip 11. A flexible resin film, metal foil, or the like is used as the oil-resistant non-swelling material sheet, and it is preferable to form the sheet in the form of a disk with holes into the desired shape using a press, then pass it through a roll core and perform a predetermined bonding process. In another embodiment of the present invention shown in FIG.
A thin disc-shaped oil-resistant non-swelling material sheet 12 is adhesively coated on the side surfaces of both ends of the roll, and the above-described heat-resistant and high hardness rubber ring 9a is further adhered onto the sheet 12 to form a molded rubber 7. An oil-resistant non-swelling material sheet 12 is placed in the middle of the rubber ring 9a. Next, a silicone rubber adhesive is applied to the rolled surface of the molded rubber and a non-adhesive sleeve 8 is coated and adhered thereto. It is necessary to form an adhesive overlay 14 at the corner of the bonded portion between the rubber ring 9a and the sleeve 8. Since the anti-offset liquid penetrates into the rubber ring 9a and the built-up adhesive 14, the surface of the rubber ring and the surface of the built-up part 14 of the adhesive are coated with fluoroelastomer paint to prevent the penetration of the anti-offset liquid. A prevention layer 15 is formed, a wear-resistant oil-resistant deformable material 13 is attached covering the corners where the fixing ring and the rubber ring contact, and the rubber ring 9a and the fluoroelastomer paint 15 are protected against physical or mechanical damage from the outside. protect against harmful effects. Next, a fixing ring 10 is attached to the side surface of the abrasion-resistant and oil-resistant deformable material 13, and this is fixed with a circlip 11.

Next, a pressure roll having a sleeve according to the present invention will be explained by way of examples.

Example 2 (see FIG. 5) The surface of a metal roll core is treated with a primer for coating with silicone rubber, and heat-curable silicone rubber (hardness: about 40°) is molded and vulcanized. Next, heat-resistant heat-curable silicone rubber (hardness approximately 45-50°)
A disc-shaped rubber ring with a hole is made using silicone rubber adhesive, which is adhered to both sides of the molded rubber attached to the roll core with silicone rubber adhesive.After rough polishing the resulting roll surface, non-adhesive tetrafluoroethylene-6F is used. The inner surface of a sleeve made of chemically propylene copolymer resin (hereinafter referred to as FEP) is etched with a mixture of sodium naphthalene and tetrahydrofuran, and then coated and bonded to the surface of a rubber roll with a silicone rubber adhesive.

Next, an oil-resistant, non-swelling, 0.05 mm thick FEP sheet or ETFE (ethylene-tetrafluoroethylene copolymer) sheet is made into a disc shape with holes similar to the one used to make the rubber ring, and is pressed using a press as shown in Figure 5-12. The FEP sheet is plastically deformed into the shape shown in the figure, and the area that will be bonded to the rubber ring and roll core is treated with the above etching solution. Glue with epoxy adhesive. The etched end-treated portion where the FEP sheet and the inner surface of the sleeve came into contact had the effect of preventing the offset prevention liquid from penetrating, even if the inner surface of the FEP sleeve and the FEP sheet were simply in contact without any special adhesion. Even better results can be obtained by heat-sealing the sleeve and FEP sheet to completely adhere them. Next, attach a fixing ring to the top of the FEP sheet and secure this ring with a circlip.
The pressure roll obtained as described above is completely prevented from penetrating the anti-offset liquid from the outside, and the rubber ring and molded rubber are completely unaffected by the anti-offset liquid, and can withstand long-term use, compared to conventional rolls. of things
It has a lifespan of more than 15 times, and there is no change in the outer diameter, hardness, or pressure of the roller over time, and the FEP sheet that comes into contact with the corner of the fixing ring does not wear or crack, and the rubber ring has no physical influence. without receiving
The drawbacks of traditional pressure rolls are completely eliminated.

Example 3 (see FIG. 6) Silicone rubber is molded onto a roll core in the same manner as in Example 2. Aluminum foil was used as an oil-resistant, non-swelling material to prevent penetration of the offset prevention liquid, and it was processed into a circular shape with holes in the same way as in Example 2, and both sides were treated with primer, which was the same as heat-resistant molded rubber. A rubber ring is made from silicone rubber with a hardness approximately 5 to 20 times higher than the mold rubber, and is adhered to the aluminum foil using a silicone rubber adhesive.Then is also adhered to the sides of both ends of the mold rubber to create a roll shape. A non-adhesive sleeve similar to that in Example 2 was internally treated with an etching solution and coated and adhered to the surface of the roll with a silicone rubber adhesive.
Next, coat the outer surface of the rubber ring attached to the roll with a fluorine-based paint (for example, product name: Perflon, Kinyosha Co., Ltd. A thin collar (packing sheet) made of nylon resin is applied to the area where the surface of the paint layer contacts the fixing ring, and then a fixing ring is applied. A pressure roll as shown in Fig. 6 was made by attaching the parallel circlips.

As shown in Fig. 6, the pressure roll obtained as described above has a structure that double prevents penetration of offset prevention liquid from the outside, so it is much more effective than conventional processing rolls. It shows excellent effects, and there is no change in the hardness or dimensions of the rubber ring, and the nip width required for fixing remains uniform over a long period of time.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional heat and pressure fusion device.
FIG. 2 shows a deformation state of the ring seal of a conventional pressure roll during use, and FIG. 4 shows a pressure roll according to the present invention. It is a diagram showing an example of the third embodiment.
The figure is a diagram showing the dimensional change of a conventional pressure roll swollen by an offset prevention liquid, and FIGS. 5 and 6 are diagrams showing other embodiments of the pressure roll according to the present invention. be. In the figure, 1... heating roll, 2... pressure roll, 3...
Heater, 4... Non-adhesive resin, 5... Metal roll tube, 6... Roll core, 7... Mold rubber, 8... Sleeve, 9... Ring seal, 9a... Rubber ring,
10...Fixing ring, 11...Circlip, 12
...Oil-resistant non-swellable material, 13...Oil-resistant variable shape material, 14...Adhesive, 15...Offset prevention liquid permeation prevention layer.

Claims (1)

[Scope of Claims] 1. In a pressure roll for an electrophotographic heating and pressure fusing device that uses an offset prevention liquid, both end surfaces of the molded rubber attached to the roll core of the pressure roll have a hardness higher than that of the molded rubber. 1. A pressure roll for an electrophotographic heating and pressure fusing device, characterized in that it is provided with a ring seal made of a heat-resistant variable shape material. 2. The electrophotographic heating pressure melting device according to claim 1, wherein the ring seals are installed on both end side surfaces of the molded rubber, and a sheet of an oil-resistant non-swellable material is further provided on the outside thereof. Pressure roll for application equipment. 3. A patent claim characterized in that sheets of a heat-resistant non-swelling material are provided on both end surfaces of the molded rubber, the ring seal is provided on the outside of the sheet, and an offset prevention liquid permeation prevention layer is further provided on the outside of the sheet. A pressure roll for an electrophotographic heating and pressure fusing device according to item 1.