US 4,251,161 AGranted

Control unit for a serial printer

AssigneeIng. C. Olivetti & C., S.p.A.

InventorsMarcello Cresti, Franco Ugo

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Abstract

A serial printer comprises a carriage 1 movable along a printing line by a motor MC with a feedback transducer FBC signalling increments of carriage advance. A daisy wheel 2 carries characters to be printed and is rotated by a stepping motor MS with a feedback transducer FBS. In order to maximize printing speed without complex control of the carriage speed a control unit signals when the carriage 1 reaches each printing point in response to feedback pulses from FBC, whether fixed or proportional spacing is used. If the motor MS has by then completed character selection, as determined by counting feedback pulses from FBS, the carriage is not stopped and printing takes place on-the-fly. If character selection has not been completed, the carriage is stopped and printing is effected when character selection is completed.

Claims9

Dependent claims

A serial printer comprising a carriage moved by a command unit along a printing line from a preceding print position to a new print position, a print hammer, a type member mounted on the carriage and rotatable intermittently, for positioning a selected character in front of said print hammer for the impact of the selected character on said print position, first sensing means responsive to the angular positions of said type-member for sensing whether a positioning operation of the selected character in front of said hammer has been effected, second sensing means for sensing positions of the carriage proximate to said new print position, and a control unit responsive to said first and second sensing means, for selectivley controlling said command unit and said hammer, wherein said control unit conditions said command unit to arrest said carriage in correspondence with said new print position in response to a not yet effected positioning of the selected character when said proximate position of the carriage is reached, wherein said control unit conditions said command unit to move said carriage through said new print position in response to an already effected positioning operation and wherein said control unit actuates said hammer when both the positioning of the selected character has been effected and said carriage has reached said new position.

Dependencies are inferred from the claim text.