JPH07285702A - Sponge rubber roll and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a silicone sponge rubber roll, in which the adhesion of toner and foreign material to the surface thereof is eliminated and a rubber roll can be rotated by the small driving force and abrasion of a rubber roll with age is reduced. CONSTITUTION:In a silicone sponge rubber roll provided with a foamed body, which has a skin layer on the surface thereof, in the peripheral part of a metal core thereof, the skin layer is formed with irregularity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicone sponge rubber for use around an electrophotographic system such as a printer, a copying machine, and a facsimile machine used as an office automation equipment, around a photosensitive drum, around a fixing portion, and for paper feeding. The present invention relates to a roll and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a charging roll, a developing roll, a conveying roll, a transfer roll and a clear roll around a photosensitive drum of an electrophotographic system such as a printer, a copying machine and a facsimile. There is a demand for downsizing and weight reduction of printing rolls, pressure rolls around the fixing section, fixing rolls, cleaning rolls, paper feed rolls, etc., and high quality printing. Requires a larger contact area at low pressure, so a sponge rubber roll was used instead of a hard rubber type rubber roll. These sponge rubber rolls are formed by forming a non-foamed and uncured rubber layer on the outer periphery of the core metal, and heating with a mold to foam and cure, or without using a mold, in a heating furnace. It is a general method to mold a rubber roll having a skin layer on the surface by a so-called free-foam curing method, or to mold a rubber roll having the skin layer removed by grinding the surface thereafter. It was The sponge rubber roll having a skin layer obtained by such a method was a rubber roll having a very high surface smoothness.

However, the sponge rubber roll having such a skin layer has a smooth surface and has an adhesive property peculiar to rubber, so that the toner easily adheres to the surface and the friction resistance of the surface is high, so that the rubber roll is There is a problem that a large driving force is required to rotate the. In order to solve this problem, a rubber roll having a surface coated with a coating material has a problem that the adhesion between the coating layer and the sponge layer is unstable, changes over time easily occur, and the durability is poor. Further, the surface of the sponge rubber roll obtained by grinding and removing the surface skin layer has a problem that its physical strength is weaker than that of the surface of the skin layer, and it gradually wears and its outer diameter changes greatly.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems of the prior art. Toners, foreign substances, etc. do not adhere to the surface of the rubber roller, and the rotational driving force of the rubber roll can be small, and it can be used for a long time. The present invention provides a silicone sponge rubber roll and a method for producing the same, which is less likely to change due to abrasion.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, and it is an effective means to provide a skin layer in order to reduce the wear that occurs on the surface over time during actual use. Further, they have found that it is effective to give unevenness to the surface in order to prevent adhesion of toner, foreign matter, etc. to the surface and reduce frictional resistance, and have completed the present invention. That is, the silicone sponge rubber roll is characterized in that the skin layer is textured in a rubber roll provided with a foamed body having a skin layer on the outer peripheral portion of the core metal, and a method for producing the same.

The present invention will be described in more detail. As a material used for a sponge rubber roll, a silicone rubber foam having excellent properties such as compression set, temperature dependence and weather resistance is preferable. When the roll is explained, it is not particularly limited,
Diorganopolysiloxane, preferably having at least two alkenyl groups in one molecule, such as a copolymer of dimethylsiloxane and methylvinylsiloxane,
Examples thereof include a copolymer of dimethyl siloxane or methylphenyl siloxane and methyl vinyl siloxane, a copolymer of dimethyl siloxane and methyl allyl siloxane, and the like. These have a silanol group, trimethyl silyl group, dimethyl vinyl group at the molecular chain end. It is blocked with a silyl group or a methylphenylvinylsilyl group. Further, the reinforcing silica is filled therein, but fumed silica, wet silica, diatomaceous earth or the like whose surface is treated with silane, siloxane or the like to be hydrophobic may be used. To this, for example, 2,2′-azobisisobutylnitrile, azodicarbonamide or the like is added as a foaming agent and a so-called organic peroxide such as benzoylperoxide is added as a curing agent.
One or more of 2,4-dichlorobenzoylperoxide, dicumylperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and the like are used in combination.

Further, as the sponge rubber roll material of the present invention, a conductive agent such as carbon black, a metal oxide and a material whose surface is subjected to a conductive treatment is added to give a conductive silicone.
A sponge rubber roll may be used, and its resistance value can be adjusted by adjusting the addition amount of the conductivity-imparting agent and the foaming ratio. In that case, as the curing method, in addition to using the above-mentioned organic peroxide, an organohydrogenpolysiloxane having at least two hydrogen atoms (≡SiH groups) bonded to silicon atoms in the molecule, that is, a molecule Methyl hydrogendiene polysiloxane whose both chain ends are blocked with trimethylsilyl group, copolymer of dimethylsiloxane and methylhydrogen polysiloxane whose both molecular chain ends are blocked with trimethylsilyl group, tetramethylhydrogencyclotetrasiloxane, etc. So-called addition-type vulcanization may be carried out using a platinum catalyst, that is, platinum black, platinum sponge, chloroplatinic acid, chloroplatinic acid, a reaction product of chloroplatinic acid and monovalent alcohol, or the like.

The present invention is a sponge rubber roll having a skin layer with a textured surface. The method for producing the sponge rubber roll is as follows.
The outer periphery of the treated core metal is uniformly molded. For this, the rubber material may be integrally dispensed together with the core metal using an extruder with a crosshead, or the material may be dispensed into the mold without heating by compression, injection or transfer method using a mold. A method of filling, integrating with the cored bar, and then taking it out may be used.

Next, the integrally molded unfoamed and uncured rubber surface is subjected to uneven processing, but the method is not particularly limited. In the previous method of filling the material in the mold,
In advance, roughen the inner surface of the mold cavity to a matte finish by an appropriate method, such as sand blasting or shot blasting,
It is also possible to form a mesh-like groove by means of etching, machining, etc., and then make an uneven surface by transferring the inner surface to the rubber roll surface.The surface can also be sandblasted or shot blasted to give a satin finish. The surface of the rubber roll may be pressed against the flat plate that has been roughened or has been subjected to a net-like groove process by etching machining or the like to perform the concavo-convex process. At this time, the roughness of the unevenness of the rubber roll surface is Rm.
ax (depth to the lowest part of the concave part based on the peak of the convex part)
0.05 to 0.5 mm is preferable, and if it is smaller than 0.05 mm, unevenness is leveled by foaming during heat foaming.
Roughness is reduced, and as a result, the effect of unevenness is likely to disappear, and if it is larger than 0.5 mm, surface wear over time tends to be large, which is not preferable. Then, it is heated, foamed and cured, but the method is not particularly limited, and it is put in a hot air drying furnace, infrared ray, far infrared ray vulcanization furnace, UHF wave vulcanization furnace or the like as it is, so-called free-flowing. It may be foamed and cured, or may be set in a cavity having a diameter larger than the dispensing outer diameter and heated and foamed by using a mold. At that time, it is preferable that the mold cavity diameter is at least 1 mm or more larger than the outer diameter of the dispensing rubber roll. This is because if it is less than 1 mm, the unevenness on the surface of the rubber roll is likely to be leveled due to the foaming pressure during foaming.

Similarly, the unfoamed and unvulcanized rubber is integrally dispensed together with the core metal, and then the rubber surface has a particle size of 0.1 to 1
It is also possible to uniformly press the particles having a diameter of mm, heat the same in the same manner, foam and harden the particles, and then remove the particles and subject the rubber surface to unevenness. At this time, the particle size is 0.1 m
If it is smaller than m, the roughness of the rubber surface tends to be small, and if it is larger than 1 mm, the surface wear tends to be large, which is not preferable. The material of the particles is not particularly limited as long as it can withstand heating, but examples thereof include glass beads, metal powder, sand and salt. Further, the smooth skin layer after foaming and curing may be provided with irregularities by an appropriate means such as sand blasting or shot blasting. In this case, however, the skin layer is excessively polished so that it does not become too thin. So you have to be careful
If possible, it is preferable to provide unevenness during unfoaming or foam hardening.

The present invention will be described in detail with reference to examples. (Example 1) Silicone compound KE904Fu
[Shin-Etsu Chemical Co., Ltd. product name] 100 parts by weight, curing agent / C-2 [same as above] 0.5 parts by weight, curing agent / C-3 [same as above] 2 parts by weight, foaming agent / AIBN [same as above] A kneaded product containing 3 parts by weight was subjected to a primer treatment in advance using an extruder equipped with a crosshead die, and the diameter was 10 mm × 26.
Extruded with a 0 mmL stainless steel core bar to obtain an integrally dispensed product with a rubber outer diameter of 14 mm, and then etching the surface in advance and pressing it onto a copper plate with a roughness Rmax of 0.1 mm, Was uniformly subjected to uneven processing, mounted in a cylindrical mold having an inner diameter of 16 mm, and heated at 200 ° C. for 30 minutes using a hot air dryer to foam-cure. After that, the rubber was cut into a length of 220 mm and further heat-treated at 200 ° C. for 4 hours using a hot air dryer to obtain a silicone sponge rubber roll having a skin layer with irregularities on the surface. Further, at the same time, a sponge rubber roll having a smooth skin layer, which was prepared in the same manner and was not subjected to surface unevenness processing, was prepared, and the friction coefficient of both was measured. The results are shown in Table 1. In addition, both
The state of toner adhesion on the surface of the rubber roll mounted on the actual machine was compared with that after 2000 sheets of A4 size PPC paper were passed and compared, the sponge rubber roll with uneven surface is better. I got good results.

[0012]

[Table 1]

(Examples 2, 3 and Comparative Example) Silicone
Rubber compound KE151u [trade name, manufactured by Shin-Etsu Chemical Co., Ltd.] 100 parts by weight, organohydrogen polysiloxane C-153A [same as above] 3 parts by weight, platinum catalyst Cat-PL-2 [same as above] 0.3 parts by weight Parts, 1 part by weight of non-acyl organic peroxide / C-3 [same as above], 6 parts by weight of acetylene black, and 2 parts by weight of blowing agent / AIBN [same as above], a kneaded product was subjected to primer treatment using an extruder. The outer diameter of the rubber is 1 with the core metal treated with electroless nickel plating on the surface of the free-cutting steel with a diameter of 8 mm x 330 mmL.
2 mm, glass beads having an average particle size of 0.3 mm were evenly pressed onto the surface, and the temperature was set in a far infrared drying furnace at 350 ° C.
After heating for 5 minutes to foam and cure, use a hot air dryer to
Heat treatment was performed at 0 ° C. for 4 hours. Then, the glass beads adhering to the surface were removed by immersing in a toluene solvent for about 1 hour for swelling, and the solvent was air-dried and volatilized to obtain a sponge rubber roll (Example 2) having a skin layer with irregularities on the surface. . Similarly, a rubber roll (Example 3) in which the skin layer on the surface is sandblasted to a Rmax of 0.01 mm (Example 3) and a rubber roll (Comparative Example) in which the skin layer is completely ground is used without foaming and pressing the glass beads. It was produced and cut into rubber lengths of 290 mm to obtain three types of rubber rolls. Table 2 shows the changes in the outer diameter of the rubber roll when these were pressed against a glass plate with a load of 1.5 kg and the rubber roll was rotated. The numbers in the table represent the reduction value (unit: mm) of the outer diameter of the rubber roll.

[0014]

[Table 2]

From these results, it can be seen that the rubber roll having the skin layer on the surface has a smaller amount of change in the outer diameter than the surface-ground rubber roll and is excellent in wear resistance.

[0016]

The silicone sponge rubber roll of the present invention has an uneven surface, as compared with the conventional silicone sponge rubber roll having a smooth skin layer, so that toner adhesion is prevented. Since the amount is small and the surface friction resistance is small, the rotational driving force of the rubber roll is small, and good printing can be performed. Further, it is a silicone sponge rubber roll having a physical strength stronger than that of a rubber roll whose surface is ground and having excellent wear resistance over time.

Claims (2)

[Claims] 1. A silicone sponge rubber roll characterized in that a skin layer is provided with a concavo-convex pattern in a rubber roll having a foamed body having a skin layer on the surface of the cored bar. 2. The silicone rubber according to claim 1, wherein an unfoamed and uncured rubber layer is provided on the outer peripheral portion of the cored bar, and the surface of the rubber layer is subjected to concavo-convex processing and then heated and foamed and cured.
A method for producing a sponge rubber roll.