Line printer

A line printer comprising:

• a main frame;
• a selectively rotatable type-carrying drum rotatably mounted in said main frame and having a plurality of rows of type in the periphery thereof corresponding to columns of letters to be printed;
• a plurality of hammers corresponding in number to said rows of type being pivotably mounted to said main frame and positioned adjacent to and spaced from said periphery of said drum for effecting the printing operation;
• a cam shaft journalled in said main frame and adapted to be continuously rotated during the printing operation by motor means;
• a sub frame;
• a plurality of selector levers pivoted at one end on a common selector lever shaft mounted in said sub frame, each being positioned in alignment with the respective hammers;
• a plurality of drive levers pivoted at one end thereof to the other ends of said selector levers, respectively, and spring biasing means connected between said sub frame and said drive levers for urging said selector levers to pivot in one direction, said drive levers being disposed adjacent to said cam shaft such that when said selector levers are pivoted in the other direction against the biasing force of said spring biasing means, the other ends of said drive levers engage said cam shaft which, during rotation thereof, operates through a cam portion thereon to push said other ends of said drive levers into abutment with one end of said hammers so as to pivot the hammers to cause them to strike against the periphery of said drum;
• a plurality of selector magnets provided in association with said selector levers, respectively;
• a plurality of selector iron pieces provided adjacent to said selector magnets, respectively, and connected to said selector levers to be attracted by the magnets when the magnets are energized whereby the selector levers are pivoted in said other direction;
• and
• a control circuit connected to said selector magnets for selectively energizing the selector magnets;
• said selector magnets, said selector iron pieces, said selector lever shaft, said selector levers and said drive levers being mounted upon said sub frame which is formed as a separate member from said main frame, and said sub frame being adjustably secured to said main frame so that the position of the sub frame is adjustable relative to the main frame, whereby said drive levers are simultaneously properly positioned with respect to said cam shaft.