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Uniform Pressure Roll

IP.com Disclosure Number: IPCOM000042672D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Bruning, TE: AUTHOR [+2]

Abstract

Paired pressure rolls are commonly used for compressing film-like media. Examples are calendering rolls for paper and pressure fusing rolls for printers. Unless steps are taken to compensate for the bending of the rolls under load, the pressure distribution across the width is nonuniform, which results in nonuniform fixing of the toner to the paper. Compensation techniques typically used in pressure fusing devices have the undesirable side effects of creating shearing and buckling forces in the media. A means is illustrated in the figure for achieving uniform pressure distribution without creating shearing and buckling forces. Three methods of compensating for the bending of the roll are low enough in cost to be used in printers.

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Uniform Pressure Roll

Paired pressure rolls are commonly used for compressing film-like media. Examples are calendering rolls for paper and pressure fusing rolls for printers. Unless steps are taken to compensate for the bending of the rolls under load, the pressure distribution across the width is nonuniform, which results in nonuniform fixing of the toner to the paper. Compensation techniques typically used in pressure fusing devices have the undesirable side effects of creating shearing and buckling forces in the media. A means is illustrated in the figure for achieving uniform pressure distribution without creating shearing and buckling forces. Three methods of compensating for the bending of the roll are low enough in cost to be used in printers. The first involves crowning the roll such that the diameter in the middle of the roll is larger than at the ends. When the rolls are loaded, their beam deflection is such that a uniform pressure is created along their length. The problem with this method is that the varying circumference of the roll results in a higher surface speed at the center. This creates a shearing force in the paper that tends to wrinkle the paper. Another common method is to skew the axes of the rolls relative to each other. The rolls then wrap around each other upon loading and create a nearly uniform pressure distribution. Since the axes of revolution are not parallel, there is a shearing force created by the translational components of the surface velocity vectors. This again can cause the paper to wrinkle. A third method decouples the fi...