JPH04298762A - Elastic roller - Google Patents

Abstract

PURPOSE:To improve the durability of the elastic roller by providing an urethane resin layer via a primer on a silicone rubber layer and essentially consisting of this primer of gamma-aminopropyl trimethoxysilane. CONSTITUTION:The silicone rubber layer having 10 to 80 deg. JIS-A hardness is provided on the arbor of the roller and the surface of this silicone rubber layer is ground to roughen the surface at need; thereafter, the surface is washed and the primer prepd. by using the gamma-aminopropyl trimethoxysilane as its essential component and properly diluting the same with an org. solvent, etc., is uniformly applied on this layer. The urethane resin is then applied at a desired thickness on this primer coated layer. Such various characteristics that while the surface layer has sufficient elasticity the layer has less permanent compression set and good wear resistance and is chemically stable are simultaneously satisfied by forming the surface layer into two-layered constitution in such a manner. Further, the interlayer adhesive strength increases as well.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic roller suitable for use as a developing roller in electrophotographic copying machines, laser beam printers, and the like.

0002

[Prior Art] Developing rollers for electrophotographic copying machines and laser beam printers have high surface conductivity, sufficient elasticity, low compression set, and a low coefficient of friction to withstand long-term use. It is necessary to satisfy various characteristics such as being small, having good wear resistance, and being chemically stable.

In order to meet these characteristics, rollers of this type have conventionally been coated with a composition made by adding conductive fillers to silicone rubber on the core shaft, or coated with a conductive composition. The core is coated with synthetic urethane rubber. However, although silicone rubber has excellent chemical stability, it has poor abrasion resistance, while urethane rubber has good abrasion resistance but has insufficient other mechanical properties, so both have their advantages and disadvantages. Ta.

[0004] As a result of the inventors' studies in order to satisfy these various characteristics at the same time, we have developed a two-layer structure in which silicone rubber with low compression set is coated on the roller core shaft, and a conductive urethane resin layer is provided on top of the silicone rubber. It has been found that the above-mentioned characteristics can be fully satisfied at the same time if the configuration is adopted. However, in this configuration, the adhesion between the silicone rubber layer and the conductive urethane resin layer is extremely poor, and even if a general-purpose silicone rubber adhesive or urethane adhesive is interposed between the two layers, the adhesive strength is extremely low. Ta. For this reason, even if such a two-layer roller is used, there is a problem that the surface layer peels off early, resulting in poor durability. Therefore, it has been desired to strengthen the adhesive force between the two layers and, by extension, improve the durability of the roller.

[0005]

[Problems to be Solved by the Invention] In view of the above points, the present invention provides an elastic roller in which a roller core shaft is coated with silicone rubber and a urethane resin layer is provided via a primer. The purpose is to significantly improve the adhesive force with the urethane resin layer and improve the durability of the elastic roller.

[0006]

[Means for Solving the Problems] The present invention provides an elastic rubber layer having a JIS-A hardness of 10 to 80 degrees on a roller core shaft, and a urethane resin layer provided thereon via a primer. In the roller, the primer is γ
- An elastic roller characterized by containing aminopropyltrimethoxysilane as a main component.

The silicone rubber material for the silicone rubber layer in the present invention has a hardness of 10 to 80 degrees (
JIS-A hardness) can be used. If the hardness after vulcanization is outside this range, sufficient elasticity may not be obtained and compression set may become large. The method for coating silicone rubber on the roller core shaft is to extrude silicone rubber that is solid at room temperature, such as heat-vulcanized silicone rubber (HTV), directly onto the core shaft using an extruder, or to form it into a sheet in advance. This can be done by a conventional method such as wrapping something around a roller core shaft, then putting it in a mold and vulcanizing it while applying pressure. Further, a room temperature liquid type material such as an addition reaction silicone rubber or a room temperature curing silicone rubber may be injected into a mold by injection molding or the like.

In the present invention, the surface of the silicone rubber layer is ground and roughened if necessary, and then washed, and then a primer containing γ-aminopropyltrimethoxysilane as the main component and diluted with an organic solvent as appropriate is applied. Apply evenly. As a coating method, spray coating, dipping, etc. can be used, and after coating to a thickness of about several μm, drying and baking are performed as necessary. Furthermore, a small amount of other adhesive compound or primer may be mixed with γ-aminopropyltrimethoxysilane within a range that does not impair the effects of the present invention. Note that although γ-aminopropyltrimethoxysilane is known as a silane coupling agent, adhesive strength equivalent to that of the present invention cannot be obtained even if other silane coupling agents are used.

[0009] Next, a urethane resin is coated on the primer coating layer to a desired thickness. As for the coating method, it is preferable to apply a resin paint in which a urethane resin is dispersed or dissolved in a suitable solvent by spray coating or the like. This surface layer made of urethane resin is provided in order to obtain the excellent abrasion resistance of urethane resin, and may be provided as thinly as does not impair various properties such as elasticity of the underlying silicone rubber layer.

[0010] When the obtained roller is used for developing purposes, a conductive substance is blended into the silicone rubber layer and the urethane resin layer so that the resistance value of each layer is 108.
It is sufficient if the conductivity is set to Ωcm or less.

The elastic roller of the present invention has a hardness of 1 after vulcanization.
It has a two-layer structure in which a urethane resin is placed on top of a silicone rubber layer of 0 to 80 degrees (JIS-A hardness), so it has sufficient elasticity and low compression set, and has good abrasion resistance and chemical resistance. It is possible to simultaneously satisfy the characteristics of stability. Furthermore, by selecting and using γ-aminopropyltrimethoxysilane as the interlayer adhesive between the silicone rubber layer and the urethane resin layer, the interlayer adhesive strength becomes extremely high, and the durability of the resulting roller is also improved.

0012

[Example] An example of the present invention will be described.

Example 1 After blasting and degreasing an aluminum core shaft with a diameter of 6 mm and a length of 300 mm, unvulcanized conductive silicone rubber (manufactured by Toray Dow Corning Co., Ltd.) was applied to the outer periphery using a rubber extruder. DY32-933U) was extrusion coated, placed in a mold, and pressure vulcanization molded. At this time, the silicone rubber had a resistance value of 102 Ωcm, a hardness of 50 degrees, and a compression set of 5%. Next, the surface of this was ground to an outer diameter of 18 mm, and then γ-aminopropyltrimethoxysilane (product name K, manufactured by Shin-Etsu Chemical Co., Ltd.)
BM903) was spray applied and air dried. Then, a conductive urethane paint (trade name: SPAREX DH20Z313, manufactured by Nippon Miractran Co., Ltd.) was spray-painted thereon and finished by drying in a constant temperature bath at 150° C. to produce an elastic roller of the present invention. The interlayer adhesive strength (peeling test: peel strength per unit length) of the obtained roller was examined and found to be 250 g/cm. Furthermore, when the obtained roller was incorporated into an actual copying machine and 10,000 sheets were passed, no image abnormality or damage to the roller occurred, and it had good durability.

Comparative Example As a comparison, rollers were manufactured in the same manner as in the examples except that various silane coupling agents other than γ-aminopropyltrimethoxysilane were used as primers, and interlayer adhesion was tested. The results were as follows.

Primer (product name)
Interlayer adhesion strength◎
・γ-Mercaptopropyltrimethoxysilane◎
(K
BM803) 40g/cm◎
・N-β (aminoethyl)γ-aminopropyltrimethoxysilane◎
(KBM603)
80g/cm◎ ・N-β (aminoethyl)
γ-aminopropylmethyldimethoxysilane◎
(KB
M602) 40g/cm◎
・γ-Aminopropyltriethoxysilane◎
(KB
E903) 140g/cm

00
16]

[Effects of the Invention] As described above, according to the elastic roller of the present invention, not only good elasticity and abrasion resistance can be obtained at the same time, but also the adhesive strength between the silicone rubber layer and the urethane resin layer is extremely high, so the durability is improved. An excellent and highly reliable elastic roller can be obtained.

Claims (1)

[Claims] Claim 1: The roller core shaft has a JIS-A hardness of 10 to 8.
1. An elastic roller comprising a 0 degree silicone rubber layer and a urethane resin layer provided thereon via a primer, wherein the primer contains γ-aminopropyltrimethoxysilane as a main component.