roller backer
A bookbinding machine, invented by the American,
Charles Starr and exhibited by him in 1851 at the
London exposition. It is used to create the
backing shoulders of a text block which has
previously been rounded, usually by hand. It
consists of a heavy roller pivoted above a pair of
jaws. The book is clamped with that part of the
text block equal to the extent of the backing
shoulders projecting above the jaws. The roller is
adjusted so that it swings back and forth across
the jaws in an arc that corresponds to the round
of the spine. The roller is then lowered so that
it presses on the spine and is rocked back and
forth to shape the spine into the proper shape,
bending the sections over the jaws and thus
creating the shoulders. If too great a pressure is
applied directly to the spine, the sections may be
buckled and creased on the binding edge; in
addition, the endpapers and several leaves of the
first and last sections may be cut by the edges of
the jaws. See also: BACKING ;ROUNDING AND BACKING
MACHINE . (164
, 339 )
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