JP2963635B2 - Pressure roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure roller in a fixing section of an electronic copying machine or a laser beam printer (hereinafter abbreviated as LBP).

[0002]

2. Description of the Related Art Conventionally, as a pressing roller in a fixing section of an electronic copying machine or an LBP, a roller in which a fluororesin sleeve is coated on the outer periphery of a rubber roller containing a cored bar is known in order to improve the releasability of toner. . The conventional roller of this type is, for example, as disclosed in Japanese Patent Publication No. 50-7097 or Japanese Patent Publication No. 51-27276, in which the inner diameter of the cylindrical mold loaded inside the cylindrical mold is reduced. Both ends of the fluororesin sleeve having a small outer diameter are fixed to the side mold that holds the metal core, and in this state, a rubber material is injected and filled into the annular space between the metal core and the sleeve at a high pressure, and the sleeve is filled with the filling pressure. It has been manufactured by a method in which the sleeve is brought into close contact with the inner peripheral surface of the cylindrical mold while expanding, and the sleeve is integrated with the rubber material.

[0003]

In the conventional pressure roller manufactured by the above method, especially when a thin fluororesin sleeve having a wall pressure of 0.1 mm or less is used, the tensile stress of the sleeve is low. In addition, there is a problem that the adhesion between the sleeve and the rubber material is not sufficient, and the sleeve and the rubber layer often peel off, resulting in a short life as a pressure roller.

In recent years, the inner surface of a fluororesin sleeve has been subjected to an etching treatment using a treatment solution obtained by dissolving sodium metal and naphthalene typified by Tetra H (trade name of Junko Co., Ltd.) in tetrahydrofuran or ethylene glycol dimethyl ether (hereinafter referred to as SNT). Abbreviated as law)
From this, it was found that by changing to a treatment method using a treatment solution in which metallic sodium was dissolved in liquid ammonia (hereinafter abbreviated as SA method), the adhesion durability between the sleeve and the rubber layer was drastically increased. A pressure roller in which the inner surface of a fluororesin sleeve has been treated by the SA method has been widely used.

[0005] However, even if a fluororesin sleeve whose inner surface is treated by the SA method is used, depending on the type of the silicone rubber, there may be no adhesion durability at all.
Such a tendency is more remarkable especially in a heat-curable silicone rubber which is cured by a peroxide than an addition-type silicone rubber. This is in contrast to the fact that the conventional fluororesin sleeve treated by the conventional SNT method did not have much selectivity in the type of silicone rubber, and that the fluororesin sleeve treated by the SA method was used. However, in some cases, a pressure roller having good durability cannot be supplied stably. Therefore, the present invention provides the above-described S
It is an object of the present invention to provide a pressure roller having good adhesion durability between the sleeve and the rubber layer even when the inner surface is treated by the method A.

[0006]

Means for Solving the Problems In order to achieve the above object, a pressure roller according to the present invention has a silicone rubber layer coated on an outer periphery of a metal core, and an inner surface of which is formed by a liquid ammo.
Etching with a treatment solution in which metallic sodium is dissolved in the near
Is intended to its features in that crosslink density of the silicone rubber layer of the pressing roller coated Te following fluororesin sleeve thickness 0.1mm was grayed treatment is 2.0 × 10 ^{over 4} mole / cc or more, the In the present invention, a silicone rubber having a crosslink density of 2.010 ^-4 mole / cc or more is used as an elastic layer covering the outer periphery of the core metal, and a 0.1 mm thick fluorine coated on the rubber is used.
Metallic sodium immersion in liquid ammonia
Having etched with a processing solution prepared by dissolving beam, the adhesion <br/> fluororesin sleeve and the elastic body layer is significantly improved, which can hold the durability of the pressing roller over time It is.

The rubber hardness of the elastic layer made of silicone rubber according to the present invention is not particularly limited, and can be arbitrarily selected within the range of 4 to 55 degrees according to JIS, and contains a base vinyl group. As the polyorganosiloxane, methylvinylpolysiloxane is generally used, but methylphenylvinylpolysiloxane and the like can also be used.

The method of compounding the filler for the elastic layer is not particularly limited, but usually 10 to 300 parts by weight of the reinforcing filler and the extending filler are used per 100 parts by weight of the base polyorganosiloxane. To some extent. As the reinforcing filler, wet silica or dry silica (fumed silica) is generally used. Here, the wet silica is a reinforcing silica made of silicon dioxide (SiO ₂ ). As a production method, a direct method of directly decomposing sodium silicate with sulfuric acid or reacting sodium silicate with salts. There are various methods such as an indirect method in which silicate is formed and then decomposed with sulfuric acid or carbon dioxide gas.

A typical wet silica is Nipsil V
N3 (trade name, manufactured by Nippon Silica Industry Co., Ltd.), Carplex CS-5 (trade name, manufactured by Shionogi Pharmaceutical Co., Ltd.), Starsil S (trade name, manufactured by Kamishima Chemical Industry Co., Ltd.), Toksil US (trade name, manufactured by Tokiyama Corporation), Shilton R-2
(Trade name of Mizusawa Chemical Industry Co., Ltd.), Hysil 223
[Hisil 223 PPG (US) product name], Ultrasil VN3 [Ultrasil VN3 Degussa (Germany) product name], Vulkasil S [Vulkasil S Bayer (Germany) product name], etc. And a grade having an average particle size of 30 μm or less, preferably 5 μm or less is used.

[0010] Wet silica is a reinforcement made of silicon dioxide produced by a thermal decomposition method of silicon halide or by heating and reducing silica sand to oxidize vaporized SiO in air or a thermal decomposition method of organic silicon compounds. Silica, Aerosil 20
0 and Aerosil R972 (trade name, manufactured by Nippon Aerosil Co., Ltd.), Cab-O-Sil MS-5 (trade name, manufactured by Cabot Corp., USA), Leolosil QS102
(Trade name, manufactured by Tokuyama Corporation). In the present invention, if necessary, wet silica and dry silica may be used in combination. Further, a wetting agent (wetter) may be added for the purpose of preventing secondary bonding due to the activity of the silica surface. Examples of these wetting agents include silicone resins, alkoxysilanes and siloxanes, hydroxysilanes and siloxanes, and silazane. , Organic acid esters, polyhydric alcohols and the like.

The bulking filler is a component necessary for maintaining the mechanical properties of the silicone rubber, that is, properties that are indispensable to function as an elastic layer, such as physical strength, rubber strength, and compression set. Quartz powder, diatomaceous earth, novacurite (siliceous sandstone), zirconium silicate, clay (aluminum silicate), talc (hydrous magnesium silicate), wollastonite (calcium metasilicate), titanium oxide, zinc oxide, oxide Examples include magnesium, alumina (aluminum oxide), barium sulfate, lithopone, molybdenum disulfide, and mica (mica powder) graphite.

In order to impart conductivity to the elastic layer, various conductivity-imparting agents may be used as fillers to reduce the volume resistivity to 10 ¹³ Ω · cm or less. As conductive carbon black such as acetylene black and Ketjen black, graphite, silver,
Examples thereof include metal powders such as copper and nickel, conductive zinc white, and carbon fibers. Carbon black is generally used.

In the present invention, a heat-resistant agent such as cerium oxide may be added.
It is not a type in which a latex made of a mixture of a fluoro rubber and a fluoro resin, such as Daiel Latex GLS-213 (trade name, manufactured by Daikin Industries, Ltd.), is coated on the outer periphery of the silicone rubber roller.
There is no need to fire at a temperature of about ° C. Therefore, it is not always necessary to add a heat-resistant auxiliary such as cerium oxide.

In general, a pressure roller made of silicone rubber is often supplied in a colored state in a reddish color, and in this case, it is common to use a reddish colorant as a coloring agent. , SRIS1108 (Japanese Rubber Association Standard) can be applied, and if it is necessary to pay attention to the orientation in the rubber during processing, Bayerox 130M (a product manufactured by Bayer AG (Germany)) Spherical grade having an average particle size of 0.3 μm or less as in
What is necessary is just to add about weight%. Recently, CP-21 (Torre Dow Corning.
In many cases, about 0.3 to 4% by weight of a silicone masterbatch having a content of about 50%, such as a product name of Silicone Co., Ltd.) is added.

As the vulcanizing agent in the present invention, in the case of a heat-curable silicone rubber, an ordinary organic peroxide for silicone rubber can be used, and benzoyl peroxide, bis 2,4-dichlorobenzoyl peroxide, Mil peroxide, di-tert-butyl peroxide, tert-butyl perbenzoate, paramonochlorobenzoyl peroxide, 2,5-dimethyl-
2,5-di- (tert-butylperoxy) -hexane, tert-butylcumyl peroxide, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyisopropyl carbonate, 1,3-bis ( Tertiary butylperoxy) -3,3,5-trimethylcyclohexane, tertiary butylperoxy 3,3,5-hexanoate and the like are exemplified, but dicumyl peroxide or 2,5-di (tertiary butyl- The use of (oxy) -hexane is common. Further, in the present invention, instead of the heat vulcanization type using the above-described organic peroxide as a vulcanizing agent, in the presence of a platinum catalyst, an addition type comprising a vinyl group-containing polysiloxane and a hydropolysiloxane may be used. Of course it is good.

As a material for the fluororesin sleeve used in the present invention, a copolymer of tetrafluoroethylene and perfluoroalkylvinyl ether (hereinafter abbreviated as PFA) having a thickness of 0.1 mm or less is generally used. According to the above, a conductivity-imparting agent such as carbon black is added to the above-mentioned PFA to obtain a conductive powder having a volume resistivity of 10 ¹³ Ω · cm or less.
A pressure roller as an FA may be formed. In particular, the present invention is effective for conductive PFA whose inner surface has been treated by the SA method described above. This means that in the case of conductive PFA, 5 parts of conductive carbon black is added to 100 parts by weight of normal PFA.
Since it is made by adding about 50 parts by weight, active points (cross-linking points) on the etched PFA surface are reduced, so that the adhesive strength between PFA and rubber can be increased by increasing the active points on the rubber side. It is thought to be.

The adhesion between the fluororesin sleeve and the silicone rubber in the present invention is performed by applying a silicone-based primer such as Chemloc 607 (trade name, manufactured by Lord Far East, Inc.) to the inner surface of the fluororesin sleeve that has been subjected to the inner surface treatment. Then, by vulcanizing the elastic layer made of silicone rubber, it can be used by being adhered to the elastic layer. Further, the adhesion of the elastic layer of the core metal can be achieved by using a silicone-based primer such as Primer No. 16 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). After previously activating the surface with sandplast or the like, degreased with methylene chloride or the like, a primer is applied, and if necessary, baked at 130 ° C. for about 30 minutes before use.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, an embodiment of the present invention will be described. As shown in FIG. 1, a pressure roller 1 has a metal core 2 covered with an elastic layer 3 made of silicone rubber. 3
Is coated with a fluororesin sleeve 4 having a thickness of 0.1 mm or less whose inner surface is treated by the SA method. The elastic layer 3 is made of a silicone rubber composition having a crosslink density of 2.0 × 10 ⁻⁴ mole / cc or more.

The crosslinking density of the silicone rubber is measured by a toluene swelling method as disclosed in Japanese Patent Publication No. 4-38579. That is, a 5 mm x 20 mm sample was cut out from a rubber sheet vulcanized and molded to a thickness of 2 mm, immersed in 50 ml of toluene, and the weight of the sample containing toluene was measured every predetermined appropriate time, and 24 hours was measured. When the difference between the two measurement values measured apart is 1% or less of the sample weight, the sample weight is defined as W (g). Next, the sample was air-dried, and then dried at 120 ° C. for 3 hours to remove toluene. The weight W ₀ (g) was measured, and the sample was placed on a platinum boat and placed in a nitrogen stream at a heating rate of 10 ° C./min or less. Heat to ℃
After holding at 900 ° C. for 10 minutes, the mixture is cooled and the weight Wf (g) of the remaining sample is measured. Using the above measurements, the number of crosslinks contained in 1 cc of vulcanized rubber, N ₀ / V ₀ (mole / cc), is calculated by the following equation.
And determine the crosslinking density.

[0020]

(Equation 1)

[0021]

(Equation 2)

The crosslink density referred to here is the crosslink formed by the vinyl group in the methyl vinyl silicone rubber,
The number of crosslinks contained per cc of silicone rubber after crosslinking, including both the crosslinks formed between the silica and the siloxane polymer in the silicone rubber. It can be adjusted by changing the ratio of the group.

The crosslinking density is 2.0 × 10 ^-4 mole as described above.
Table 1 shows the physical properties of the silicone rubber of
C, and the rollers of Examples 1 to 9 were prepared by changing the physical properties of the fluororesin layer to I, II, and III as shown in Table 2, and the crosslink density was 2.0 × 10 ⁻⁴ mole. The physical properties of the elastic layer made of silicone rubber of less than / cc are represented by D and E shown in Table 1, and the sleeve 4 and the elastic layer 3 of the pressure roller of the comparative example using the fluororesin layer shown in Table 2 are used. Was subjected to an adhesive peel test. As this adhesive peel test, two slits were made at 10 mm intervals in the axial direction of the material,
A part of the surface sleeve 4 is peeled off by pulling, and this part is clamped to a tensile tester and subjected to a 90 ° peeling test.
With respect to the roller after heating for 70 hours, the rubber residual ratio and the adhesive strength of the peeled surface were examined. The physical properties of the silicone rubber material of the elastic layer 3 and the physical properties of the fluororesin layer 4 used in the experiment are shown in Tables 1 and 2 as described above, and the results of the peeling test are shown in Table 3.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

From the results shown in Table 3 above, the initial examples 1 to 9 all have good adhesive strength, while the comparative examples 1 to 9.
In No. 3, the rubber residual ratio was found to be slightly lower. However, in the adhesion test after 70 hours at 230 ° C. (indicated as simply after heating in Table 3), the crosslink density was 2.0 × 10 ⁻⁴ mole / c.
c It was found that only the materials of Examples 1 to 9 using the above silicone rubber retained the adhesive strength, and all of Comparative Examples 1 to 6 lost the adhesive strength.

Next, in order to evaluate the durability of each of the above samples, a paper passing test was performed by a copying machine, and the results shown in Table 4 were obtained.
As a method of evaluating the durability in this paper passing test, the diameter of the heating roller is 50 mm, its surface temperature is 200 ° C, and the nip load is
With a specification of 60kgf / total and wind speed of 250mm / sec, 50 blank sheets /
After passing between the fixing rollers at a speed of one minute, the occurrence of peeling of the sleeve 4 and the elastic layer 3 was evaluated as its life. In addition,
As the pressure roller in the evaluation method, a roller having an outer diameter of 50 mm, a thickness of an elastic layer made of silicone rubber of 5 mm, a thickness of a fluororesin sleeve of 50 μm, and a length of the elastic layer of 340 mm was used.

[0029]

[Table 4]

As can be seen from the results in Table 4, the roller of this embodiment has extremely good adhesion between the fluororesin sleeve 4 and the elastic layer 3 and has a long-term durability. There was no occurrence of fixing unevenness, paper wrinkles, curling, or the like, which would cause a problem in image formation.

Although the silicone rubber of the present invention has been mainly described as being bonded to a fluororesin sleeve whose inner surface has been treated by the SA method, not only such bonding but also SN has been described.
It is also used for bonding to a fluororesin sleeve that has been internally treated by the T method or a fluororesin sleeve that has been treated by corona discharge or the like.

[0032]

The pressure roller according to the present invention has a crosslink density of 2.0 × 10 ⁻⁴ mole as an elastic layer covering the outer periphery of the cored bar.
Use silicone rubber of / cc or more and coated with it
The inner surface of the 0.1mm thick fluororesin sleeve is
Etching with a processing solution in which metallic sodium is dissolved
Since the treatment is performed, the adhesion between the fluororesin sleeve and the elastic layer is remarkably improved, and the durability as a pressure roller can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a pressure roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure roller 2 Core metal 3 Silicone rubber layer 4 Fluororesin layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16C 13/00 F16C 13/00 A G03G 15/20 103 G03G 15/20 103 // B29K 27:12 83:00 105: 24 B29L 31:32 (58) Fields investigated (Int.Cl. ⁶ , DB name) B29D 31/00 B29C 35/02 B29C 63/18 C08J 7/00 C08L 83/00 F16C 13/00 G03G 15/20 B32B 27 / 00-27/42

Claims (3)

(57) [Claims] 1. A metallic sodium rubber layer coated on the outer periphery of a silicone rubber layer coated on the outer periphery of a core metal in liquid ammonia.
0.1mm thickness etched with processing solution in which
The following fluororesin sleeve Te coated pressure roller crosslink density of the silicone rubber layer of 2.0 × 10 ^{over 4} mole / cc
A pressure roller characterized by the above. 2. The method according to claim 1, wherein the fluororesin sleeve is tetrafluoro.
Co of Roechiren and path perfluoroalkyl vinyl ether
Volume resistivity is 10 ¹³ Ω by adding conductive material to polymer
2. The method according to claim 1, wherein the conductive property is not more than cm.
Pressure roller. 3. The method according to claim 1, wherein said silicone rubber is a heat-curable silicone.
The rubber according to claim 1 or 2,
Pressure roller.