Advancing material of indeterminate length – By orbitally traveling material-engaging surface – Comprising rotary pinch pair
Reexamination Certificate
1998-08-24
2001-09-11
Hughes, S. Thomas (Department: 3726)
Advancing material of indeterminate length
By orbitally traveling material-engaging surface
Comprising rotary pinch pair
C226S177000
Reexamination Certificate
active
06286741
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a low-cost feed roller structure which can reliably transport a photosensitive material while maintaining the accuracy of the roller, and is preferably used in, for example, a printer-processor and the like.
2. Description of the Related Art
For example, a plurality of processing tanks which contain processing solutions or water for color development, bleach-fixing, rinsing, stabilization, and the like are provided in a photosensitive material processing apparatus (e.g., a printer-processor and the like) serving as an automatic processor. As a photosensitive material such as photographic printing paper or the like is successively conveyed into these processing tanks, the photosensitive material is processed.
Namely, a processing rack provided with a multiplicity of feed roller pairs is inserted into each processing tank. These feed rollers nip and transport the photosensitive materials for processing.
Recently, however, the use of photosensitive materials with broad widths, which is becoming increasingly desired, necessitates that the roller surface length, i.e. the length in the direction of the axis of the feed roller be lengthened so as to process these broad photosensitive materials.
However, if a conventional roller, which is formed in a pipe shape by extrusion molding of a resin material, is simply lengthened to broaden the roller surface length, then the concern arises that the deflection of the central part of the feed roller will become too marked and transportation failure, inclination, meandering, and the like of a photosensitive material may occur. A highly rigid metal pipe, rod or the like may be inserted into the core of the feed roller to increase the rigidity thereof so that the deflection can be reduced, however, if a metal pipe or the like is inserted into a feed roller, the manufacturing cost of the feed roller is disadvantageously increased.
SUMMARY OF THE INVENTION
In view of the aforementioned fact, an object of the present invention is to obtain a low-cost feed roller structure which can reliably transport a photosensitive material while maintaining the accuracy of the roller.
According to a first aspect of the present invention, a feed roller structure comprises a roller, having a coaxially-shaped two-layer structure formed by two-layer extrusion molding using thermoplastic resin, which is rotatably supported on a processing rack and feeds a photosensitive material inside a processing tank, wherein the two-layer structure of the feed roller comprises an internal layer portion and an external layer portion wherein the modulus of elasticity of either the thermoplastic resin constituting the external layer portion of the two-layer structure or the modulus of elasticity of the thermoplastic resin constituting the internal layer portion of the two-layer structure is 240 kgf/mm
2
or more, the modulus of elasticity of the thermoplastic resin constituting the other layer portion is 900 kgf/mm
2
or more, and the external diameter of the feed roller is 13.7 mm or more.
According to a second aspect of the present invention, a feed roller structure comprises a roller, having a coaxially-shaped two-layer structure formed by two-layer extrusion molding using thermoplastic resin, which is rotatably supported on a processing rack and feeds a photosensitive material inside a processing tank, wherein the two-layer structure of the feed roller comprises an internal layer portion and an external layer portion wherein the modulus of elasticity of the thermoplastic resin constituting the external layer portion of the two-layer structure is 240 kgf/mm
2
or more, the modulus of elasticity of the thermoplastic resin constituting the internal layer portion of the two-layer structure is 900 kgf/mm
2
or more, and the external diameter of the feed roller is within the range of from 13.7 mm to 45 mm.
In the feed roller structure of the present invention, a coaxially-shaped two-layer structure formed using thermoplastic resins, having a layer with a low modulus of elasticity and a layer with a high modulus of elasticity obviates the need for the insertion of a core such as a metal pipe or the like so that reduced manufacturing costs are achieved.
In the present invention, the modulus of elasticity is 240 kgf/mm
2
or more in the layer with the low modulus of elasticity, and the modulus of elasticity is 900 kgf/mm
2
or more in the layer with the high modulus of elasticity.
In the feed roller structure of the present invention, a two-layer structure is formed from a layer with a low modulus of elasticity and a layer with a high modulus of elasticity. The layer with a low modulus of elasticity is preferably formed using a simple thermoplastic resin substance, and is preferably formed using olefinic elastomer. The layer with a high modulus of elasticity has a modulus of elasticity of 900 kgf/mm
2
or more, and is preferably formed using thermoplastic resin containing fillers.
In the feed roller structure of the present invention, a two-layer structure is formed from an external layer portion with a low modulus of elasticity and an internal layer portion with a high modulus of elasticity. The external layer portion is preferably formed using a simple thermoplastic resin substance, and is preferably formed using olefinic elastomer. The internal layer portion has a modulus of elasticity of 900 kgf/mm
2
or more, and is preferably formed using thermoplastic resin containing fillers.
In the feed roller structure of the present invention, the external diameter of the roller is 13.7 mm or more, and preferably, the nip surface length is within the range of from 230 mm to 400 mm. In the feed roller structure of the present invention, when the external diameter of a roller is A, the internal diameter of the external layer is B, and the internal diameter of the internal layer is C, their ratio is preferably within the range of A:B:C=10:8 to 9.4:5 to 7.3.
In the feed roller of the present invention, the rigidity of the feed roller is enhanced by providing a layer having a high modulus of elasticity while maintaining the minimum external diameter of the feed roller so that the photosensitive material can be reliably transported while the accuracy of the roller is maintained when the feed roller, which is rotatably supported by a processing rack, nips and transports the photosensitive material inside a processing tank, without the occurrence of transportation failure, meandering, and the like of the photosensitive material.
In the feed roller structure of the present invention, when the external diameter of a roller is A, the internal diameter of the external layer portion is B, and the internal diameter of the internal layer portion is C, their ratio is preferably within the range of A:B:C=10:8 to 9.4:5 to 7.3, whereby a feed roller, which not only has a high rigidity but also has a superior workability, can be formed.
The manufacturing costs of the feed roller can be further reduced by forming the layer with the low modulus of elasticity using low-cost olefinic elastomer. Further, in the feed roller of the present invention, a layer with a high modulus of elasticity is formed using thermoplastic resin containing fillers to thereby obtain a highly rigid feed roller with a modulus of elasticity of 900 kgf/mm
2
or more.
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Butler Marc W.
Fuji Photo Film Co. , Ltd.
Hughes S. Thomas
Sughrue Mion Zinn Macpeak & Seas, PLLC
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