Browse Prior Art Database

Hot Roll Treatment

IP.com Disclosure Number: IPCOM000084505D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brandon, FY: AUTHOR [+3]

Abstract

In one form of electrophotographic copying thermoplastic toner powder is transferred from an image area to a copy substrate. Subsequently, the thermoplastic toner is fixed to the copy substrate by feeding the substrate through a pair of pressurized rolls, at least one of which is heated to a temperature which causes the powder to fuse to the substrate. Where the copy substrate is paper, which it usually is, the paper will normally include rosin sizing. Such rosin sizing is thermoplastic which allows some amounts of rosin to be transferred from the paper to the surface of the hot roll. As the amount of rosin on the hot roll surface increases, there is an increasing tendency for paper passing through the hot roll system to cling to and wrap around the hot roll, rather than pass through the roller system.

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Hot Roll Treatment

In one form of electrophotographic copying thermoplastic toner powder is transferred from an image area to a copy substrate. Subsequently, the thermoplastic toner is fixed to the copy substrate by feeding the substrate through a pair of pressurized rolls, at least one of which is heated to a temperature which causes the powder to fuse to the substrate. Where the copy substrate is paper, which it usually is, the paper will normally include rosin sizing. Such rosin sizing is thermoplastic which allows some amounts of rosin to be transferred from the paper to the surface of the hot roll. As the amount of rosin on the hot roll surface increases, there is an increasing tendency for paper passing through the hot roll system to cling to and wrap around the hot roll, rather than pass through the roller system.

Potential paper wrap problems due to rosin contamination of the hot roll are avoided, by periodically heating the roll to a temperature greater than the normal hot roll fusing temperature for a short period of time. The elevated temperature causes the rosin sizing which is present on the hot roll to either volatilize from the roll or to change its characteristics, in such a way that it no longer causes paper to adhere to the hot roll.

This extreme heating procedure is capable of being initiated either by a machine operator, or as a programmed part of the machine's operating cycle, such as, during nonoperating hours or as a part of an automatic ma...