Paper thickness adjusting mechanism for impact printer

Claim 1

An impact printer comprising a platen, a pair of fixed guide rails positioned parallel to one another and said platen, a marking module including first bearing means for supporting said module upon one of said guide rails and second bearing means for supporting said module upon the other of said guide rails, said first and second bearing means supporting said module for reciprocating movement parallel to said platen, and including adjustment means for pivoting said first bearing means about the axis of said one of said guide rails, and for causing said second bearing means to rotate and to be laterally displaced about the axis of said other of said guide rails, said adjustment means being characterized by including a toggle member including a first section pivotably connected to said marking module, a rotatable shaft acting on a second section of said toggle member for moving said toggle member to shift the position of said marking module, said rotatable shaft being substantially normal to said guide rails, said second bearing means including a first portion supported upon said toggle member, and a second portion supported upon said rotatable shaft, said first and second bearing portions opposing one another on opposite sides of said other of said guide rails, biasing means for urging said first and second bearing portions toward one another, resilient means for separating said marking module from said second section of said toggle member, and control means secured upon said rotatable shaft for adjusting the distance of separation between said marking module and said second section of said toggle member upon rotation of said shaft, said control means comprising positioning means and a control knob for locating said positioning means.