Patent Application
20070045935
1. Field of the Invention
This invention relates to a feed roller apparatus, comprising; a feed roller centerpiece having first and second ends, a shaft operatively connected to the first and second ends of the centerpiece, and a textured metallic layer located substantially adjacent to an outer surface of the centerpiece.
2. Description of the Related Art
Prior to the present invention, as set forth in general terms above and more specifically below, it is known, that inkjet printers incorporate shaft assemblies to transport paper from the input region of the printer, through the print zone, and to the output area of the printer. These shafts must accurately accelerate and transport the paper, position the paper to very high tolerance in the print zone, and control the removal of the paper for output.
Traditional feed roller designs have incorporated rubber tire feed rollers. While these designs have been successful in the past, there are several fundamental limitations of this technology that cause it to be unsuitable for the newest generation of printers. For example, rubber tire rollers deform over time where the upper pinch rollers rest on the tires due to the high normal force applied to the pinch rollers. This deflection creates a variation in diameter of the feed roller, thereby changing the speed at which the paper is advanced during printing and causing errors in the absolution position of the paper in the print zone. These effects create an uneven distribution of ink on the page, manifesting itself in periodic banding on the printed material.
It is also known that metal shaft assemblies do not deflect under the higher normal force used for controlling the media. This allows for much better control of the paper speed and position in the print zone. While metal shafts with adhesive and grit coatings have been used in competitive printers for several years, the primary disadvantage of the current solutions is that the shafts are a single function shaft. The printers require multiple motors to drive the feed roller, carriage, pick tire, and other functions of the printer. Also, the adhesive and grit texture used can be scraped off due to abusive handling during shipping and assembly, or when printing high volumes of paper. Also, paper dust tends to accumulate on the adhesive and grit coatings. Consequently, a more advantageous system, then, would be provided if the banding could be eliminated while avoiding the use of adhesive and grit coatings.
It is apparent from the above that there exists a need in the art for a feed roller that eliminates periodic banding on the printed material and avoids the use of adhesive and grit coatings. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.
Generally speaking, an embodiment of this invention fulfills these needs by providing a feed roller apparatus, comprising; a feed roller centerpiece having first and second ends, a shaft operatively connected to the first and second ends of the centerpiece, and a textured metallic layer located substantially adjacent to an outer surface of the centerpiece.
In certain preferred embodiments, the feed roller centerpiece is constructed of extruded aluminum and includes a web structure on the inside for stiffness. Also, the shaft includes at least two shafts such that one shaft is inserted into one end of the centerpiece and the other shaft is inserted into the other end of the centerpiece. Finally, the textured metallic layer is constructed of any suitable meltable material which can be applied to the outer surface of the centerpiece using metal deposition arc spray technology.
In another further preferred embodiment, the feed roller apparatus uses arc spray (metal deposition) coating for the grit texture which is combined with a three-piece, close tolerance, feed roller assembly that is lightweight and accurate.
The preferred feed roller apparatus, according to various embodiments of the present invention, offers the following advantages: lower cost due to the faster cycle time capability; higher benefit to the final product, as the shaft can provide multiple functions in the printer; infinite texture characteristics, as the material can be changed to anything that can be melted and sprayed; enhanced supply chain as the number of suppliers can be streamlined by having the complete assembly done at each supplier location; decreased banding; reduction in printer weight; and elimination of the grit and adhesive. In fact, in many of the preferred embodiments, these factors of lower cost, higher benefit to the final product, infinite texture characteristics, decreased banding, reduced printer weight, and the elimination of the grit and adhesive are optimized to an extent that is considerably higher than heretofore achieved in prior, known feed roller apparatus.
The above and other features of the present invention, which will become more apparent as the description proceeds, are best understood by considering the following detailed description in conjunction with the accompanying drawings, wherein like characters represent like parts throughout the several views and in which:
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It is to be understood that one of the key aspects of the present invention is that the precision grit feed roller 40 can incorporate multiple functions into the media handling unit from a single power source. For example, the present invention does not need separate motors to drive shafts 4, 6 and center section 8. Also, the shafts 4, 6 can employ various stages of knurls and pressed on gears to provide transmission functions.
Once given the above disclosure, many other features, modifications or improvements will become apparent to the skilled artisan. Such features, modifications or improvements are, therefore, considered to be a part of this invention, the scope of which is to be determined by the following claims.
