Printer

Claim 1

In a printer having respective control means for print hammers which are arranged in a plurality of columns and each of which is displaceable between a rest position and a print position, and having respective deformable elastic bodies maintained in deformed condition by the associated print hammers in the rest position, improved magnetic circuit control means associated with each of said columns for holding each said print hammer at said rest position and selectively releasing said print hammers for displacement to said print position, a permanent magnet common to each of the columns, a first hammer hold magnetic circuit portion associated with each hammer including a portion of the associated print hammer and a second reLease magnetic circuit portion associated with each hammer including release coil means, said release coil means including means for applying signals thereto, said first and second magnetic circuit portions being connected in parallel with said permanent magnet, each of said magnetic circuit control means being adapted to hold said respective hammer at said rest position and to release said respective hammer upon application of a signal to its release coil means by said signal applying means in a direction so as to decrease the magnetomotive force applied to said hammer, the energy stored in the respective deformed body displacing said respective hammer from said rest position to said print position upon said decrease in said magnetomotive force, said release coil having applied thereto a further signal by said signal applying means when said associated hammer is displaced from its rest position and at least one other hammer associated with said common permanent magnet is to be released from its respective rest position so that the operating point of said common permanent magnet is substantially returned to the original operating point before said at least one other print hammer is released from a rest position.