Patent ID: 7080892

Claim:
A printing apparatus which performs printing by driving a printhead on the basis of print data transmitted from a host apparatus, comprising: main scanning means for scanning the printhead in a main scanning direction with respect to a printing medium; buffer means for storing print data; reception means for receiving, from the host apparatus, main scanning/printing direction information representing a main scanning/printing direction of the printhead; storage means for storing, in said buffer means, print data corresponding to the printing direction represented by the main scanning/printing direction information received from the host apparatus; and control means for controlling printing by the printhead on the basis of the main scanning/printing direction information and the print data stored in said buffer means, wherein said buffer means stores print data used for printing during scanning of the printhead by said main scanning means, a data amount which can be stored is smaller than a print data amount for printing by one main scanning of the printhead by a width printable by main scanning of the printhead by said main scanning means, said storage means stores print data received from the host apparatus during the printing by scanning the printhead in the main scanning direction by said main scanning means, said control means starts the printing before completing receiving of print data for one main scanning of the printhead, receives print data transmitted by the host apparatus in parallel with the printing by scanning of the printhead after starting the printing and, if print data is interrupted during the main scanning, performs the main scanning again in a direction represented by the main scanning/printing direction corresponding to the current main scanning, and when the print data are stored up to a position corresponding to a predetermined column unit in said buffer means, said control means starts printing by the printhead on the basis of the main scanning/printing direction information and the print data stored in said buffer means.