Browse Prior Art Database

FUSER ROLL TEMPERATURE CONTROL

IP.com Disclosure Number: IPCOM000027795D
Original Publication Date: 1999-Oct-31
Included in the Prior Art Database: 2004-Apr-09
Document File: 4 page(s) / 148K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is a fuser temperature control for use in an electrophotographic printing machine. Paper with toner applied thereon passes between a pair of rollers. When the rollers are heated the toner melts and attaches to the paper by flowing into micro-crevices in the paper. Since the paper briefly contacts the heated rollers, roll pressure, temperature, and toner characteristics are critical to the fusing process.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 54% of the total text.

Page 1 of 4

XEROX DISCLOSURE JOURNAL

FUSER ROLL TEMPERATURE CONTROL

Proposed Classification Richard H. Tuhro U. S. C1. 399/330

Int. Cl. G03g 15/20

14

Disclosed is a fuser temperature control for use in an electrophotographic printing machine. Paper with toner applied thereon passes between a pair of rollers. When the rollers are heated the toner melts and attaches to the paper by flowing into micro-crevices in the paper. Since the paper briefly contacts the heated rollers, roll pressure, temperature, and toner characteristics are critical to the fusing process.

Coated papers present special problems. A temperature set too high vaporizes water trapped in the paper causing the coating to blister. Alternatively, when the temperature is too low the toner does not melt sufficiently for proper adhesion. The difference between paper blister and toner blister (not sticking) commonly called "temperature droop" is relatively small and in the range of about 12°C. Normally, a good temperature control system maintains this temperature, but if heavier paper is used the heat removed from the fusing rollers can exceed the heater's ability to replace it. This is especially true in mid- volume printing machines operating on limited electrical line power. In this case,

XEROX DISCLOSURE JOURNAL - Vol. 24 No. 5 SeptembedOctober 1999 215

[This page contains 1 picture or other non-text object]

Page 2 of 4

FUSER ROLL TEMPERATURE CONTROL (Cont'd)

"temperature droop" causes the fuser to operate outside its narrow range of effectiveness when fusing a number of heavy sheets.

Increasing the thermal mass of the fuser roll reduces "temperature droop". This works up to a point where the fuser thermal mass can only be increased within the limits of available space. Furthermore, increasing thermal mass increases the time required to heat the fuser rolls to operating temperature. Since warm up time is often a machine operating goal that can counter the low electrical power goal, the thermal mass of the fuser rolls is limited.

Two problems associated with temperature control of a heated roll fusing system have been identified: limited ability to accommodate peak loads from heavy paper, and extended warm up time. This disclosure addresses these problems with a fuser temperature control shown as fuser roll 10 in the accompanying figure. Fuser roll 10 comprises a concentric tube having an outer layer 12 of metal or rubber, a first chamber 14 containing a material that aides temperature control, and a second chamber 16 for holding a heater (not shown). The material contained in chamber 14 undergoes a phase change to absorb or release heat at the fuser set point temperatures. A thumper 18 induces freezing of the phase control material. Suitable phase change materials can be fou...