Method and apparatus for setting and varying margins and line spacing on data printers

A control system for a data printer of the general type having at least one print head and means for holding printable stock in position relative to said print head for printing thereby, and including means for effectively moving the print head and printable stock relative one another for printing vertically spaced horizontal lines of characters with a line spacing between successive lines of characters comprising a plurality of discrete individually variable vertical increments, said control system comprising:

• a manually actuable control key device having at least one control key and means coupled thereto for producing electrical signals upon actuation of said control key;
• line-advancing means operatively associated with said means for moving said print head and printable stock, for causing advancement of the printable stock transversely relative to each said horizontal line of characters after printing thereof, thereby spacing each horizontal line of printed characters from the next ensuing horizontal line of characters to be printed;
• said line-advancing means including means responsive to said electrical signals by varying the amount of spacing between certain successive character lines as a function of particular actuation of said control key, said amount of spacing having at least three settings;
• said line-advancing means being responsive to particular electrical signals produced by said particular actuation of said control key by varying the line spacing between certain horizontal character lines in the particular number of said individually variable vertical increments selected by the said particular actuation of said control key.

In a data printing machine having a print head, a print head drive means coupled to said print head for laterally moving said print head to any of a plurality of mutually-spaced known positions along a print head lateral travel path, and a print media drive means for incrementally advancing a printing media with respect to said print head in a manner whereby successive lines of data printed on said printing media along said print head lateral travel path lie generally parallel to one another and in a manner whereby adjacent lines of data have a standard line spacing between them, said standard line spacing comprising a particular number of vertical increments, a positioning means including:

• a position-monitoring means operatively coupled to at least one of said print head and said print head drive means, for determining the lateral position of said print head along said path relative to a known reference location therealong;
• memory means operatively coupled to said position-monitoring means and said print media drive means for storing indicia representative of said lateral position of said print head, representative of said known reference location, representative of a given left-hand margin position and indicia representative of certain of said particular number of vertical increments of printing media advancement;
• control means coupled to said memory means, to said position-monitoring means, to said print media drive means, and to said print head and said print head drive means, for controlling the position of said print head relative to said printing media and said travel path, and actuating said print head to print along said path;
• a keyboard coupled to said control means for providing an interface for transmission of control signals from an operator to said control means, said control means selectively responding to said control signals to set said left-hand margin position and the vertical spacing between printed lines;
• said keyboard including:
• a left-direction head drive control means coupled to said print head drive means and to said memory means for moving said print head to the left of said set left-hand margin position, in order to reset said left-hand margin position leftward;
• and
• a right-direction head drive control means coupled to said print head drive means and to said memory means for moving said print head to the right of said set left-hand margin position, in order to reset said left-hand margin position rightward;
• and
• a run state control means for enabling said left-direction head drive control means to reset said left-hand margin position to the left a predetermined number of said mutually-spaced known positions for each increment of operation of said left-direction head drive control means;
• said left-direction head drive control means operable independently of the position of said print head along said lateral print head travel path and during periods of relative print head movement as during printing by said data printing machine, and for enabling said right-direction head drive control means to reset said left-hand margin position to the right a predetermined number of said mutually-spaced known positions, for each increment of operation of said right-direction head drive control means, said right-direction head drive control means operable independently of the position of said print head along said lateral print head travel path and during periods of relative print head movement as during printing by said data printer.

A method of printing data for a data printer by using a print head drive means to drive a print head laterally along a printing surface and past a plurality of mutually-spaced known positions lying along a lateral print head travel path, and vertically positioning said printing surface with respect to said print head such that successive lines of data printed on said printing surface along said print head lateral travel path have predetermined vertical spacing between said lines of data, and including the positioning of the print head by the steps of:

• laterally moving said print head to a desired margin position along said travel path;
• using electrically actuated signal means and a digital memory device to store a coded signal which identifies said desired margin position;
• using said stored coded signal in an electrical control means to index the printing of data by said print head so that the lines of data printed thereby are indexed at said desired margin position;
• and
• establishing a "run" state during which the print head moves laterally along said travel path printing characters and a left-direction print head drive control means is enabled in a manner to move a left-hand margin to the left incrementally in response to operation of said left-direction print head drive control means, said left-direction print head drive control means being operable independently of the position of said print head along said lateral print head travel path and during periods of relative print head movement as during printing by said data printer, and during which a right-direction print head drive control means is enabled in a manner to move said left-hand margin to the right incrementally in response to operation of said right-direction print head drive control means, said right-direction print head drive control means being operable independently of the position of said print head along said lateral print head travel path and during periods of relative print head movement as during printing by said data printer.