Patent Application
20090261525
1. Field of the Invention
This invention relates to a paper-feeding roller assembly designed for use in a machine that requires paper-feeding, and more particularly, to a magnetic paper-feeding roller assembly that uses magnetic attraction forces to facilitate a paper-feeding operation.
2. Description of the Related Art
In the course of rotation of the rollers 31, 32, the teeth 311 of the catch roller 31 catch the piece of paper 2 that is being fed through the gap 30. To ensure that the piece of paper 2 can be fed through the gap 30 without being marked-up or damaged, the size of the gap 30 is appropriately set by the end caps 33. If the gap 10 is too large, the catching force may be insufficient to catch the piece of paper 2 to feed it through the gap 10. On the other hand, if the gap 30 is too small, the pressing force against the piece of paper 2 can become excessive, resulting in press marks being formed thereon by the teeth 311.
As a result, the manufacturing and assembly requirements of the end caps 33 and the rollers 31, 32 are high. Such high precision in manufacture can be a challenge and may complicate the assembly process. Furthermore, any other components associated with the movement of the roller assembly 3, such as the spring elements 34, may also damage the piece of paper 2.
Therefore, it is an object of the present invention to provide a magnetic paper-feeding roller assembly that is capable of overcoming the above-mentioned drawbacks of the prior art.
According to the present invention, a magnetic paper-feeding roller assembly is adapted to feed a piece of paper in a machine that requires paper-feeding and that includes a casing. The magnetic paper-feeding roller assembly includes a first roller and a second roller, both of which are adapted to be pivotably mounted in the casing. The first roller is made of a magnetically attractive material. The second roller produces a magnetic force to magnetically attract the first roller toward the second roller so as to maintain a predetermined gap between the first roller and the second roller.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:
Referring to
The second roller 6 has a peripheral surface 611 and includes an anti-slip layer 612 disposed on the peripheral surface 611. The second roller 6 further includes a nonmagnetic tube 61 that has the peripheral surface 611, and at least one magnetic unit 62 disposed in the tube 61. The tube 61 has opposite ends, and, in the preferred embodiment, a pair of the magnetic units 62 are disposed in the tube 61 proximate respectively to the ends of the tube 61. In the preferred embodiment, the two magnetic units 62 are disposed in the tube 61 in such a manner that like magnetic poles of the magnetic units 62 face each other. The second roller 6 additionally includes two caps 63 that cover respectively the ends of the tube 61.
In the preferred embodiment, the tube 61 is made of a nonmagnetic stainless steel material, and the first roller 5 is made of a magnetically attractive stainless steel material. It is noted that the magnetic units 62 produce magnetic fields that extend out of the tube 61, as shown in
Therefore, unlike the prior art described beforehand, because neither of the first and second rollers 5, 6 is formed with paper-catching teeth, the holding force of the first and second rollers 5,6 can be distributed evenly and smoothly across the piece of paper 7 without leaving pinch marks thereon and thereby avoiding damage to the piece of paper 7.
It should be noted that, in other embodiments of the present invention, the paper-feeding function can be performed without the use of the anti-slip layer 612. The anti-slip layer 612 disposed on the peripheral surface 611 of the tube 61 only enhances the holding and frictional contact force with the paper 7 during a paper-feeding operation.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
