Flight Time Adjustment of Print Hammers
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Impact printers with electromagnetically actuated clapper-type armatures and hammer flight times adjusted as a function of the armature seal time (the time elapsing between the firing of the armatures and their hitting the magnet yoke) are subject to flight time differences and thus to different impact energies leading to non-uniform ribbon wear. If the flight time is adjusted (under load) by changing the magnetic resistance of the air gap of the clapper-type armatures, the impact energy is substantially the same. When multi-ply paper is printed, the magnetic resistance of the air gap is reduced by a high-conductivity metallic bar which is used for the magnetic flux and which is common to all clapper-type armatures of a print hammer bank.