Printer system and method of controlling operation of the same

摘要

To reduce the necessary storage capacity of the internal memory of a printer, a printing start command is transmitted from a printer controller to a printer by asynchronous transfer before the transmission of image data. Isochronous transfer of image data to be printed in packet units starts upon elapse of a fixed period of time following transmission of the printing start command. Image data thenceforth is transmitted from the printer controller to the printer successively by isochronous transfer at a fixed period. Since the image data is transmitted from the printer controller to the printer at the fixed period, printing can be performed at a constant speed without requiring that the printer be provided with an image memory for storing image data representing one frame of an image. In a case where a transfer request command is supplied from the printer to the printer controller, the image data is transmitted from the printer controller to the printer in response to the transfer request command. <IMAGE>