Line printer

A line printing method for a line printer having plural printing elements comprising the steps of:

• a) receiving gradation scale values of pixels for a line to be printed;
• b) storing a plurality of tables for correcting a density variation caused by common resistance unevenness;
• c) determining arithmetically a number of printing elements to be operated for printing for each particular gradation scale value based upon the gradation scale values for the line to be printed received in said step a);
• d) storing the number of printing elements determined for each particular gradation scale value in said step c);
• e) retrieving an optimal table for each gradation scale value to be printed from the plurality of tables stored in said step b) based upon the number of printing elements stored in said step d) and the gradation scale values received in said step a);
• and
• f) printing the line based upon the optimal tables retrieved in said step e),
• the gradation scale values received in said step a) being provided to the printing elements in parallel for printing in said step f).

A line printing system for a line head having a plurality of heating elements and capable of printing with a plurality of gradation scale values comprising:

• memory means for storing received gradation scale values of pixels for a line to be printed;
• arithmetic means, coupled to said memory means, for determining a number of heating elements to be heated for each of the gradation scale values for the line to be printed based upon the gradation scale values stored in said memory means;
• storage means for storing a plurality of tables for correcting a density variation in a printed line caused by common resistance unevenness;
• second storage means for storing the number of heating elements to be heated as determined by said arithmetic means for each of the gradation scale values;
• and
• control means, coupled to the line head, for retrieving an optimal table for each gradation scale value for the line to be printed from said storage means based upon a gradation scale value and the number of heating elements to be heated for the gradation scale value stored in said second storage means and for controlling the line head to print the line in accordance with the retrieved optimal tables,
• the gradation scale values being provided from said memory means to the line head in parallel for printing.

A line printing method for a line head having a plurality of heating elements and capable of printing with a plurality of gradation scale values comprising the steps of:

• a) storing received gradation scale values of pixels for a line to be printed;
• b) determining a number of the heating elements to be heated for each of the gradation scale values for the line to be printed based on the stored gradation scale values;
• c) storing the number of heating elements to be heated as determined in said step b);
• d) storing a plurality of tables for correcting a density variation in a printed line caused by common resistance unevenness;
• e) retrieving an optimal table for each gradation scale value for the line to be printed based upon a gradation scale value and the number of heating elements to be heated for the gradation scale value as stored in said step c);
• and
• f) controlling the line head to print the line in accordance with the retrieved optimal tables,
• the gradation scale values stored in said step a) being provided in parallel to the line head for printing in said step f).