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METHOD FOR PREVENTING WRAPPING OF EXTRUDATE ON NIP ROLL

IP.com Disclosure Number: IPCOM000027300D
Original Publication Date: 1996-Feb-29
Included in the Prior Art Database: 2004-Apr-07
Document File: 2 page(s) / 75K

Publishing Venue

Xerox Disclosure Journal

Abstract

Proposed is a method for preventing the adhesion of extrudate to a nip roll. Referring to the accompanying figure, there is shown an extrusion system 10 comprising a heated extruder barrel 12, nip rolls 16 and 18, belt 22, and a sprayer 20. When belt 22 is used as a post extrusion cooling station, extrudate 14 frequently wraps around one of the rolls 16 and 18. Wrapping occurs when the extrudate 14 melt temperature is, for example, at approximately 420 degrees Fahrenheit for extruding xerographic toners. Most likely, the extrudate 14 will wrap around the lower roll 18 rather than the upper roll 16. Observations indicate that the adhesion of extrudate 14 to roll 18 prevails during winter months when the dew point temperature of the ambient is lower than that at the surfaces of rolls 16 and 18.

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XEROX DISCLOSURE JOURNAL

METHOD FOR PREVENTING Proposed Classification WRAPPING OF EXTRUDATE ON
NIP ROLL
George R. Hsu
Luis Garcia
David Douthitt
Kathy Wright

U.S. C1.425/308 Int. C1. AOlj 21/02

- 10 12

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16

I

20

XEROX DISCLOSURE JOURNAL - Vol. 21, No. 1 January/February 1996 85

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METHOD FOR PREVENTING WRAPPING OF EXTRUDATE ON NIP

ROLL (Contld)

Proposed is a method for preventing the adhesion of extrudate to a nip roll. Referring to the accompanying figure, there is shown an extrusion system 10
comprising a heated extruder barrel 12, nip rolls 16 and 18, belt 22, and a sprayer 20. When belt 22 is used as a post extrusion cooling station, extrudate 14 frequently wraps around one of the rolls 16 and 18. Wrapping occurs when the extrudate 14 melt temperature is, for example, at approximately 420
degrees Fahrenheit for extruding xerographic toners. Most likely, the extrudate 14 will wrap around the lower roll 18 rather than the upper roll 16.
Observations indicate that the adhesion of extrudate 14 to roll 18 prevails during winter months when the dew point temperature of the ambient is lower than that at the surfaces of rolls 16 and 18.

The problem is corrected by spraying the lower roll 18 with a fine mist of water from sprayer 20. The water forms a thin film on the surface of roll 18 and acts as a release agent to prevent extrudate 14 from adhering thereto. Water is projected upward from sprayer...