Descender printing system for dot matrix printer

Claim 1

In a dot matrix printer of the kind comprising a print head, including a plurality of print elements disposed in a vertical array, for printing characters on a record sheet supported upon a platen in a format m × n of m horizontal column increments and n vertical row increments, a carriage for moving the print head across the record sheet in a horizontal printing direction with the lowermost printing element normally aligned with a horizontal base print line on the record sheet, and control means, including a FIFO input store, for actuating the print elements and the carriage in response to a received signal including a series of code words representative of characters to be printed and of other functions of the printer, the improvement comprising: descender decoder means for decoding code words representative of descender characters that include descender components to be located below the base print line, prior to printing; descender shift means, coupled to the descender decoder means, for shifting the record sheet upwardly through a distance L equal to p row increments, from a normal print position to a descender print position, thereby aligning p print elements below the base print line for printing each descender character, where p < n; and shift reset means, included in the descender shift means, for shifting the record sheet downwardly through distance L from the descender print position to the normal print position, after completion of printing of a descender character, to permit printing a subsequent character entirely above the base line.

Claim 7

The method of printing, utilizing a dot matrix printer of the kind comprising a print head including a plurality of print elements disposed in a vertical array, for printing characters on a record sheet supported upon a cylindrical platen in a format m × n of m column increments and n row increments, a carriage for moving the print head across the record sheet in a horizontal printing direction with the lowermost printing element normally aligned with a horizontal base print line on the record sheet, and control means, including a FIFO input store, for actuating the print elements and the carriage in response to a received signal including a series of code words representative of characters to be printed and of other functions of the printer, comprising the following steps: A. monitoring the code words to detect each code word representative of a descender character that includes a descender component to be located below the base print line, prior to printing; B. shifting the record sheet upwardly through a distance L equal to p row increments, from a normal print position to a descender print position, to align p print elements of the print head below the base print line for printing each descender character, where p<n; and C. shifting the record sheet downwardly through distance L from the descender print position to the normal print position, after completion of printing of a descender character, to permit printing a subsequent character entirely above the base line.

Claim 8

The method of printing, utilizing a dot matrix printer of the kind comprising a print head including a plurality of print elements disposed in a vertical array, for printing characters on a record sheet supported upon a cylindrical platen in a format m × n of m column increments and n row increments, a carriage for moving the print head across the record sheet in a horizontal printing direction with the lowermost printing element normally aligned with a horizontal base print line on the record sheet, and control means, including a FIFO input store, for actuating the print elements and the carriage in response to a received signal including a series of code words representative of characters to be printed and of other functions of the printer, comprising the following steps: A. monitoring the code words to detect each code word representative of a descender character that includes a descender component to be located below the base print line, prior to printing; B. shifting the record sheet upwardly through a distance L equal to p row increments, from a normal print position to a descender print position, to align p print elements of the print head below the base print line for printing each descender character, where p<n; and C. shifting the record sheet downwardly through distance L from the descender print position to the normal print position, after completion of printing of a descender character, to permit printing a subsequent character entirely above the base line.