Roll or roller – Concentric layered annulus – Specific composition
Reexamination Certificate
2002-11-27
2004-09-21
Rosenbaum, Irene Cuda (Department: 3726)
Roll or roller
Concentric layered annulus
Specific composition
C492S059000, C428S492000
Reexamination Certificate
active
06793611
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper-feeding roller and a method of manufacturing the paper-feeding roller. More particularly, the present invention relates to a paper-feeding roller having a high degree of flexibility and moldability and having improved performance of feeding objects such as paper for plain paper copy (PPC) and capable of effectively preventing non-feeding of silica paper.
2. Description of the Related Art
The rubber roller is used in a paper-feeding mechanism of an ink jet printer, a laser printer, an electrostatic copying apparatus, a facsimile apparatus, an automatic teller machine machine (ATM), and the like. The rubber roller is required to feed objects such as a sheet of paper or a film by picking up the objects one by one separately from the objects piled up one upon another. Therefore, the rubber roller is demanded to have a high degree of flexibility and wear resistance.
The paper-feeding roller of this kind is desired to feed various kinds of printing media such as paper for PPC, silica paper, Chinese paper, an OHP film, and photo-printing paper by picking them up one by one separately without non-feeding thereof.
As disclosed in Japanese Patent Application Laid-Open No. 11-236465, the present applicant proposed the paper-feeding roller composed of the thermoplastic elastomer composition formed by mixing the rubber component, the hydrogenated styrene thermoplastic elastomer, and the olefin resin with one another; dynamically crosslinking the rubber component with the resinous crosslinking agent; and dispersing the rubber component in the hydrogenated styrene thermoplastic elastomer and the olefin resin. In the thermoplastic elastomer composition, the mixing ratio of the hydrogenated styrene thermoplastic elastomer as well as the olefin resin to the rubber is set to a certain range. Thereby the paper-feeding roller composed of the thermoplastic elastomer composition is favorable in its wear resistance, friction coefficient, compression set, and capable of preventing occurrence of blooming. Thus the paper-feeding roller is superior in its feeding performance.
The paper-feeding roller disclosed in Japanese Patent Application Laid-Open No. 2-70636 has the rubber layer containing 100-300 parts by weight of the softener and 10-300 parts by weight of titanium oxide for 100 parts by weight of EPDM (ethylene-propylene-diene rubber) in the surface thereof. The paper-feeding roller is intended to prevent ultraviolet rays from deteriorating its friction coefficient by the use of the EPDM rubber and the titanium oxide.
The paper-feeding roller disclosed in Japanese Patent Application Laid-Open No.2001-38971 is composed of silicone rubber containing the inorganic fibrous reinforcing material and the inorganic particulate filler. Titanium oxide is exemplified as the inorganic particulate filler. The proposal is intended to provide the paper-feeding roller superior in unadhesiveness to tack paper which has adhesiveness on the back side of thermal recording paper.
However, the paper-feeding roller proposed by the present applicant and disclosed in Japanese Patent Application Laid-Open No. 11-236465 has a possibility of non-feeding of paper containing much silica, in the case where it feeds a large number of the paper containing much silica, although the paper-feeding roller has a high friction coefficient for plain paper. Thus the paper-feeding roller has room for improvement in the feeding force for the silica paper or the like.
The vulcanized EPDM rubber roller and the vulcanized chlorinated polyethylene rubber roller hitherto used are liable to give rise to non-feeding for silica paper. Further these substances have a low moldability.
Since the paper-feeding roller disclosed in Japanese Patent Application Laid-Open No. 2-70636 contains the EPDM rubber only, the paper-feeding roller has a low force for feeding paper Immediately after the paper is started to be supplied to the roller and has problems that the material has a low moldability and the manufacturing cost is high.
Since the paper-feeding roller disclosed in Japanese Patent Application Laid-Open No.2001-38971 is composed of the silicone rubber, the paper-feeding roller has a low force for feeding paper immediately after the paper is started to be supplied to the roller. Further the cost of the material for the paper-feeding roller is high and has a low moldability.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-described problems. Therefore it is an object of the present invention to provide a paper-feeding roller having rubber-like durability, elasticity, flexibility, resin-like moldability, and a high wear resistance and a sufficient force for feeding silica paper.
To solve the above-described problem, the present invention provides a paper-feeding roller formed by cylindrically molding a thermoplastic elastomer composition containing a thermoplastic resin or a thermoplastic elastomer in which a rubber or a thermoplastic elastomer which can be crosslinked is dispersed by dynamic crosslinking. A surface layer of the paper-feeding roller contains titanium oxide at not less than 1.5% nor more than 50% in a volume fraction.
The thermoplastic elastomer composition of the paper-feeding roller of the present invention contains the thermoplastic resin or the thermoplastic elastomer in which the rubber or the thermoplastic elastomer which can be crosslinked is dispersed by dynamic crosslinking. Therefore the paper-feeding roller has a rubber-like durability, elasticity, flexibility, resin-like moldability, and a high wear resistance. The paper-feeding roller contains the titanium oxide at not less than 1.5% nor more than 50% in a volume fraction in its surface layer which contacts objects such as paper. Therefore the paper-feeding roller reduces the degree of non-feeding of silica paper which is a problem to be solved and has a preferable feeding force before and after paper is supplied thereto.
The amount of the titanium oxide to be contained in the surface layer of the paper-feeding roller in a volume fraction is not less than 1.5% nor more than 50%, favorably not less than 3.0% nor more than 45%, and more favorably not less than 6.0% nor more than 40%.
If the amount of the titanium oxide is contained in the surface layer of the roller in the volume fraction at less than 1.5%, it is impossible to obtain sufficient feeding force for silica paper. If the amount of the titanium oxide is contained in the surface layer of the roller in the volume fraction at more than 50%, the roller has a high hardness. Consequently the roller has a low friction coefficient or a low mechanical strength. Thus there is a possibility that the roller cannot be put into practical use.
The surface layer means the range of the thickness of the roller less than 5% and preferably less than 3% of the entire thickness thereof from the upper surface thereof. The surface layer may appear when the wear of the roller advances during the use thereof. In the case of a dynamically crosslinked material, a skin rich in resin and not crosslinked thermoplastic elastomer is formed on the surface layer of the roller. Thus it is necessary that the amount of the titanium oxide contained in the resinous phase (matrix phase) falls in the above-described range.
It is preferable that the thermoplastic elastomer composition is formed by dispersing a compound (B) containing a rubber component whose main component is EPDM by dynamic crosslinking in a compound (A) containing a styrene thermoplastic elastomer as a main component thereof. Thereby it is possible to increase an initial friction coefficient of the roller for plain paper and also increase the feeding force thereof for initial and subsequent feeding of silica paper. Thus the roller is capable of displaying high and stable feeding force for various kinds of paper.
The compound (A) contains not less than 15 nor more than 500 parts by weight of a softener and favorably not less than 25 nor more than 400 parts by we
Hattori Takayuki
Mizoguchi Tetsuo
Okuyama Hideyuki
Birch & Stewart Kolasch & Birch, LLP
Cuda Rosenbaum Irene
Sumitomo Rubber Industries Ltd.
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