The term ''fusing fix'' denotes the degree of permanence of an electro
photographic toner image that has been thermally attached to a paper s
ubstrate by a hot roll fuser. The widespread change from acid to alkal
ine papermaking for commercial copy papers was accompanied in many cas
es by a reduction in fusing fix. To study this problem, a set of 25 mo
del papers was produced with three different types of internal size, t
hree types of inorganic filler, and three types of surface treatment.
The papers were extensively characterized for their chemical and physi
cal properties, sample sets were printed in three different high-speed
copiers, and the fusing fix of the resulting images was quantified by
the crease test. Out of 47 measured parameters, the crease width had
a significant correlation only with the dispersive component of the su
rface energies of the papers. A hypothesis was constructed to explain
how changes in the paper constituents affect both the surface energy a
nd fix of the papers.