Printing apparatus of character wheel selection, stop and simultaneously printing type

Claim 1

A printing apparatus of the character wheel selection, stop and simultaneously printing type comprising: a plurality of character wheels; a shaft rotatably bearing said character wheels; a plurality of friction springs engaged with said character wheels each having a normally smaller inner diameter than the diameter of said shaft to frictionally engage the circular surface thereof and thereby transmit a rotational force from said shaft to said character wheels; a ferro-magnetic member provided on a side of each of said character wheels; a comb-tooth-like magnetic plate having a permanent magnet and being magnetically engagable with said ferro-magnetic members to thereby apply a restraining force to said character wheels; a plurality of coils each associated with a character wheel for disengaging said magnetic plate from said ferro-magnetic members at selected times, thereby causing associated character wheels to rotate with said shaft under the rotational forces transmitted by said springs; stop means for simultaneously causing each of said character wheels to be stationary at a prescribed printing position; an eccentrically mounted printing platen for effecting printing when said plural character wheels are caused to be stationary by said stop means; gears for rotating said shaft and said printing platen; and a motor engaged with said gears; wherein, during a first rotation of said shaft, said coils are selectively energized to cause associated character wheels to rotate therewith, during a second rotation of said shaft, said stop means causes said character wheels to be stationary at prescribed printing positions and said platen effects printing, and during a third rotation of said shaft, said stop means releases said character wheels causing them to rotate to prescribed reset positions to be there restrained by said magnetic plate.