JPH0273282A - Pressurizing roller for toner image fixing device and production thereof - Google Patents

Abstract

PURPOSE:To decrease the contamination with toners and to improve fixability by constituting a coating for covering a core roller of an elastic material formed by vulcanizing an ethylene acryl rubber compsn. CONSTITUTION:Transfer paper P with its transfer surface faced upward is carried into a feed base 3 at the time of fixing of a toner image T. The toner image T carried between a fixing roller 1 and a pressurizing roller 21 is welded to the transfer paper P and is ejected to the outside of a machine via an ejection base 4. The pressurizing roller 21 is formed of the core roller 101 made of metal and the coating layer 111 with which the outer peripheral surface of the roller is coated. The coating layer 111 is constituted of the elastic material formed by adding 2.5pts.wt. lubricant/vulcanizing agent to 100pts.wt. ethylene acryl rubber compsn. and vulcanizing the compsn. The fixability obtd. by continuous copying is then good and the contamination with the toners is decreased. The winding of the transfer paper P on the roller 21 and the generation of back stains are prevented.

Description

Detailed Description of the Invention A1 Object of the Invention (1) Industrial Application Field The present invention relates to a pressure roller for a toner image fixing device used in, for example, an electrophotographic copying machine, and in particular to a pressure roller for a toner image fixing device used in an electrophotographic copying machine. The present invention relates to a pressure roller that rotates while being pressed by a fixing roller in order to heat and fix an image, and a method for manufacturing the same.

(2) Conventional technology Conventionally, this type of pressure roller has been used as (a) one in which the coating layer covering the core roller is made of silicone rubber (see Japanese Patent Application Laid-Open No. 59-215848); (b) coating layer of,
An inner layer made of silicone rubber, ethylene/propylene rubber, etc., and a toner-releasable outer layer made of a fluorine resin tube laminated on the outer circumferential surface of the inner layer (
(Refer to Japanese Patent Publication No. 47-20747, Japanese Patent Publication No. 618469), (C) The coating layer is made of an inner layer made of silicone rubber and a toner-releasable outer layer made of a fluorine resin laminated on the outer peripheral surface of the inner layer. Composed (Unexamined Japanese Patent Publication 1983
-217010, JP-A No. 61-185775), etc. are known.

(3) The invention seeks to solve i! ! ! However, in the case of the pressure roller in (a) above, the material is expensive, and the toner release agent applied to the fixing roller easily swells, resulting in a decrease in physical properties such as hardness and tensile strength. In addition, in the case of the pressure roller (b), there are problems such as increased material cost for the outer layer and poor recovery of the concave nip formed when the pressure roller stops rotating. Furthermore, in the case of the pressure roller (C), there is a problem that the outer layer has poor abrasion resistance and poor adhesion.

On the other hand, in terms of manufacturing, in the case of the pressure roller mentioned above, there is a problem in that the tube coating process is complicated and the manufacturing cost is high, and in the case of the pressure roller mentioned in (C), When forming the outer layer, it is necessary to apply fluorine resin powder directly or in the form of a Latinx to the outer surface of the inner layer, and then bake it at a high temperature of 300°C or higher, which reduces equipment costs and consumption. There is a problem that this results in an increase in the amount of energy and therefore a high production cost.

An object of the present invention is to provide the pressure roller and its manufacturing method that can solve the various problems described above.

B1 Structure of the Invention (1) Means for Solving the Problems The present invention provides a pressure roller that rotates under pressure from a fixing roller in order to heat and fix a toner image formed on a sheet-like substrate. The first feature is that the covering layer is made of an elastic body obtained by vulcanizing an ethylene-acrylic rubber composition.

Further, in the present invention, in a pressure roller that rotates under pressure from a fixing roller in order to heat and fix a toner image formed on a sheet-like substrate, a coating layer that covers a center roller is formed on an inner layer and an outer circumferential surface of the inner layer. The second feature is that the inner layer is made of an elastic material obtained by vulcanizing an ethylene-acrylic rubber composition, and the outer layer is made of fluororubber.

Furthermore, in manufacturing a pressure roller that rotates while being pressed by a fixing roller in order to heat and fix a toner image formed on a sheet-like substrate, the present invention involves subjecting an ethylene-acrylic rubber composition to vulcanization molding. and a step of sequentially applying a fluororubber composition solution, drying and baking to the outer peripheral surface of the inner layer to obtain a thin outer layer of fluororubber. This is the third feature.

(2) Effect According to the first feature, the elastic body made by vulcanizing the ethylene/acrylic rubber composition has excellent heat resistance and toner release agent resistance, so that the hardness and tensile strength of the coating layer are improved. Since the deterioration of physical properties such as the like is suppressed, and the concave nip recovers well, changes in the outer diameter of the pressure roller can be minimized. Furthermore, since the composition has low toner stain resistance, it is possible to prevent the sheet-like substrate from wrapping around the pressure roller and from staining the back of the sheet-like substrate due to molten toner, and the composition is relatively inexpensive. Therefore, the manufacturing cost of the pressure roller can be reduced.

According to the second feature, it is possible to provide a pressure roller that has excellent toner stain resistance and wear resistance in addition to the above characteristics. Also, since the outer layer only needs to be extremely thin,
It is possible to suppress an increase in the manufacturing cost of the pressure roller due to the use of fluorine rubber.

Furthermore, according to the third feature, the forming process of the inner layer and the forming process of the outer layer can be simplified, and especially when forming the outer layer, the low baking temperature allows the outer layer to be firmly bonded to the inner layer at a high temperature. Can be done.

(3) Embodiment FIG. 1 shows a toner image fixing device used in an electrophotographic copying machine, which consists of a fixing roller 1 located on the upper side and heated to a predetermined temperature, and a pressurizing roller 1 on the lower side. Both rollers 1.2° are in sliding contact with each other, the fixing roller l is moved clockwise, and the pressure roller 2. rotate counterclockwise.

On the right side of the pressure roller 21 is a carrying-in table 3 for sheet-like substrates, and on the left side is a carrying-out table 4 for sheet-like substrates. It is arranged close to the outer peripheral surface.

A toner release agent applying mechanism 5 is provided on the fixing roller 1 side. The applying mechanism 5 includes a container 6 containing a silicone oil-based toner release agent, a metering roller 7 whose outer periphery is partially soaked in the toner release agent, and a metering roller 7 .
It includes a metering blade 8 that is close to the outer peripheral surface, and a donor roller 9 that rotates in sliding contact with the metering roller 7 and the fixing roller 1, respectively.

When fixing a toner image, a sheet-like substrate, such as a transfer paper P, on which the toner image T is formed, is conveyed on a loading table 3 with its transfer surface facing upward, and is transferred to a fixing roller 1 and a pressure roller 28. The toner image T is fused to the transfer paper P there.

Thereafter, the transfer paper P is conveyed on the carry-out table 4 and ejected out of the machine.

After the toner release agent adheres to the outer circumferential surface of the metering roller 7 , the adhesion amount is adjusted by the metering blade 8 , and then transfers to the donor roller 9 , whereupon it is applied to the outer circumferential surface of the fixing roller 1 . This toner release agent prevents the toner image T from being transferred to the outer peripheral surface of the fixing roller 1.

Next, the pressure roller 2I will be described in detail.

The pressure roller 21 is a metal core roller 10. and a coating layer 111 that covers the outer peripheral surface of the coating layer 11.
．． is composed of an elastic body made from a vulcanized ethylene-acrylic rubber composition.

The ethylene/acrylic rubber composition includes ethylene,
This corresponds to a copolymer of methyl acrylate and a carboxyl group-containing crosslinking site 7mer to which a vulcanizing agent is added. This type of composition is commercially available from DuPont under the trade name Baymac G. If necessary, a reinforcing filler such as carbon black, an anti-aging agent, a vulcanization aid, a polyester plasticizer, etc. are added to the composition.

Since the elastic body has excellent heat resistance and toner release agent resistance, the covering layer 11. The pressure roller 2. suppresses deterioration of physical properties such as hardness and tensile strength, and also has good recovery properties of the concave dip n. The change in the outer diameter of the can be minimized.

While the fixing operation is stopped, the fixing roller 1 and the pressure roller 2. is in direct contact with the fixing roller L, and the toner adhering to the fixing roller L is transferred to the pressure roller 2. The coating layer 11. may be transferred to the coating layer 11. Since the toner stain resistance is low, it is possible to prevent the transfer paper P from being wrapped around the pressure roller 21 and the back of the transfer paper P from being stained due to the molten toner.

Furthermore, since the composition is relatively inexpensive, the manufacturing cost of the pressure roller 2I can be reduced.

Covering layer 11. For molding, conventionally known methods such as press molding and injection molding are applied.

The fixing roller 1 is made by laminating a coating layer 14 such as fluororubber on the outer circumferential surface of a hollow core-forming roller 13 having a heater 12 therein.

FIG. 2 shows another embodiment of the pressure roller, and the pressure roller 2□ is made up of a metal core roller 10□ and a coating layer 11□ covering the outer peripheral surface of the roller, and the coating layer 11z is , an inner layer 11a and a thin toner releasable outer layer 11b laminated on the outer peripheral surface of the inner layer 11a.

The inner layer 11a is made of an elastic material obtained by vulcanizing an ethylene/acrylic rubber composition in the same manner as described above, and the outer layer 11b is made of fluororubber.

The fluororubber is a fluorinated elastic polymer, and therefore is a vulcanized fluororubber composition, and includes any conventionally known fluororubber compositions, such as:
Vinylidene fluoride-based fluorine comb compositions such as vinylidene fluoride/hexafluoropropylene copolymer, vinylidene fluoride/hexafluoropropylene/tetrafluoroethylene terpolymer, tetrafluoroethylene/propylene copolymer, and perfluorovinyl ether This applies to rubber compositions based on rubber compositions.

Pressure roller 2, which will be described later. In the production of the above-mentioned vinylidene fluoride-based fluorine comb composition, for example, DuPont's trade name Pyton E-60C is used from the viewpoint of processability and performance.

As described above, when the outer layer 11b made of fluororubber is provided on the outer peripheral surface of the inner layer 11a, the pressure roller 2□ has excellent toner stain resistance and abrasion resistance in addition to the above-mentioned properties of the inner layer 11a. can be provided.

Furthermore, since the outer layer 11b may be thin, it is possible to suppress an increase in the manufacturing cost of the pressure roller 2t due to the use of fluororubber. The thickness of the outer layer llb is preferably 200μ
m or less.

The inner layer 11a is the covering layer 11. The outer layer 11b is formed by applying a fluororubber composition solution, drying, and baking to the outer peripheral surface of the inner layer 11a. This baking process involves vulcanization of the fluororubber composition.

The fluororubber composition solution is an emulsified aqueous solution (latex) of the fluororubber composition, a vulcanizing agent, etc., or a solution obtained by dissolving the fluororubber composition in a solvent and adding a vulcanizing agent, etc. Refers to materials that can form a fluororubber layer by coating and heating and drying.9 Examples include those in which a vinylidene fluoride-based fluororubber composition is dissolved in a ketone solvent and vulcanized with a polyamine or polyol-based vulcanizing agent. be able to.

As a method for applying the fluororubber composition solution, conventionally known spray coating, dip coating, etc. are commonly used.

The baking temperature of the fluororubber composition after coating and drying is 180℃.
~230'C1 Also, the appropriate baking time is 4 to 16 hours.

According to the manufacturing method, the process of forming the inner layer 11a and the process of forming the outer layer 11b can be simplified. especially,
When forming the outer layer 11b, the outer layer 11 is heated at a low temperature.
b can be firmly adhered to the inner layer 11a.

Hereinafter, specific examples will be described.

[Example 1] Pressure roller 2 in FIG. In the production of Tsukusela DT) was kneaded using an oven roll to obtain a sheet-like product.

The sheet-like material is wound around an iron core roller 10 coated with adhesive, placed in a press molding machine, and heated to 177°C1.
Vulcanization molding was carried out under conditions for 40 minutes, and then the surface was polished to finish the outer diameter, thereby obtaining a pressure roller 21 having a coating layer 11+.

The pressure roller 21 is mounted on an FX5990 electrophotographic copying machine (
Continuous copying was performed using a toner image fixing device manufactured by Fuji Xerox Co., Ltd.).

The fixability of the images obtained by this continuous copying was satisfactory.

Also, the coating layer 11 after passing 10,000 sheets. The change in hardness was within 7°, and the change in outer diameter was also small. Covering layer 1
1. Although some toner stains were observed on the surface of the pressure roller 2. There was no occurrence of wrapping of the transfer paper or staining of the back of the transfer paper.

[Example 2] In manufacturing the pressure roller 2□ shown in FIG. 2, the coating layer 11 of Example 1 was used. An inner layer 11a having the same structure as the above was vulcanized and molded by the same method.

Vulcanization to prepare a fluorine rubber composition solution
15 parts by weight of magnesium oxide (trade name: Carbon MT) were mixed to obtain a mixture, and this mixture @ parts by weight of IJlO was
The mixture was added to a mixed solution of 63 parts by weight of methyl ethyl ketone and 27 parts by weight of methyl isobutyl ketone as an organic solvent and thoroughly stirred.

The fluorine rubber composition solution was applied to the surface of the inner layer 11a by air spray coating, and after air drying for about one day, it was placed in a heating furnace and baked at 200 ° C. for 54 hours. A pressure roller 2□ having a fluororubber outer layer 111b having a thickness of about 40 μm was obtained.

Continuous copying was performed using the pressure roller 2□ under the same conditions as in Example 1.

The fixability of the image obtained by this continuous copying was satisfactory (trade name: Paiton E-60C).

Further, the change in hardness of the coating layer 11□ after passing 100,000 sheets was within 4°, the amount of wear was less than 1 μm, and no change in outer diameter was observed.

There was almost no toner lη on the surface of the outer layer 11b, and the adhesive strength between the inner and outer layers 11a and 11b was maintained.

C9 Effects of the Invention According to the invention described in claim (1), it is possible to provide an inexpensive pressure roller that is durable and has low toner stain resistance.

Further, according to the invention as set forth in claim (2), it is possible to provide an inexpensive pressure roller with particularly improved toner stain resistance and abrasion resistance.

Furthermore, according to the invention described in claim (3), it is possible to simplify the pressure roller manufacturing operation, reduce manufacturing costs, and particularly improve the adhesive strength of the inner and outer layers.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing a toner image fixing device to which one embodiment of the present invention is applied, and FIG. 2 is a cross-sectional view of another embodiment of the present invention. P... Transfer paper as a sheet-like substrate, T... Toner image, 28, 2□... Pressure roller, 10. ．． 10.・・・
・Core roller, 11+, ]lz...covering layer, Ila...
・Inner layer, llb...outer layer patent Applicant: Fuji Xerox Co., Ltd. Representative Patent Attorney Kendo Ochiai 1) Hidetaka Naka 2
:〉1 Figure 1 7/1

Claims (1)

[Scope of Claims] (1) In order to heat and fix the toner image formed on the sheet-like substrate, in the pressure roller that rotates while being pressed by the fixing roller, the coating layer covering the center roller is made of ethylene acrylic. A pressure roller for a toner image fixing device, comprising an elastic body made of a vulcanized rubber composition. (2) To heat and fix the toner image formed on the sheet-like substrate,
In the pressure roller that rotates under pressure from the fixing roller,
The coating layer that covers the core roller is composed of an inner layer and a thin toner-releasable outer layer laminated on the outer peripheral surface of the inner layer, and the inner layer is made of an elastic body made of a vulcanized ethylene-acrylic rubber composition, and A pressure roller for a toner image fixing device, wherein the outer layer is made of fluororubber. (3) In manufacturing a pressure roller that rotates while being pressed by a fixing roller in order to heat and fix the toner image formed on a sheet-like substrate, an ethylene-acrylic rubber composition is vulcanized and molded to provide elasticity. and a step of sequentially applying a fluororubber composition solution, drying, and baking to the outer peripheral surface of the inner layer to obtain a thin outer layer of fluororubber. A method for manufacturing a pressure roller for a toner image fixing device.