Control method of ink jet printer

An ink jet printer in which a carriage is reciprocateably disposed along a platen and a plurality of ink jet heads each having a nozzle are mounted on the carriage in such a manner that said nozzles are opposed to a printing face of said platen, comprising:

• a control circuit, said control circuit comprising:
• a CPU;
• a RAM in which predetermined record data for one line and timing data for ink ejection transmitted from the CPU are written;
• a RAM controller for controlling said RAM based on an output signal from said CPU;
• and
• a timing signal generating circuit for receiving the record data and the timing data for each dot read from said RAM by said RAM controller to transmit the record data and the timing data to a head driver for operating the nozzle of each of said ink jet heads;
• wherein said timing data is adjusted by said control circuit to adjust ejection timing of the ink from the nozzle.

An ink jet printer having a plurality of ink jet heads which are mounted on a carriage that reciprocates in a direction substantially orthogonal to a conveying direction of a recording sheet and are deviated in the reciprocating direction of the carriage, comprising:

• a CPU for outputting record data;
• a record data memory for sequentially storing a predetermined volume of record data while said ink jet heads are moving along a recording path;
• a timing data memory for associating the same ejection timing of each of said ink jet heads with a different bit to form one byte, for storing timing data with the number of bytes larger than the number of bytes necessary for determining ejection time of one dot into an address position which is associated with the ejection timing, and for storing data indicative of the ejection timing of each ink jet head in an address corresponding to the ejection timing of each ink jet head;
• a timing signal generating circuit for reading and outputting the record data for one dot corresponding to each ink jet head from said record data memory, and for reading data indicative of the ejection timing of each ink jet head for each dot in address order from said timing data memory to output an ejection signal at a predetermined ejection timing corresponding to each ink jet head;
• and
• a head driver for operating each ink jet head based on said record data for each dot and said ejection signal corresponding to each ink jet head to eject the ink corresponding to said record data at said predetermined ejection timing.