Patent ID: RE41043

Claim:
A duplex printing method in a printing apparatus having a duplex printing function to print incoming print data on both sides of a single print sheet, the duplex printing method comprising: sequentially converting the incoming print data into images corresponding to respective pages and storing the images of the pages; determining whether there are the images having two side pages to be printed on both sides of the single print sheet among the images of the respective pages; if it is determined] wherein upon determining that there are the images having the two side pages, formingt a dual queue having both odd page image related information and even page image related information corresponding to the two side pages, respectively; variably scheduling a printing sequence of the pages to be printed using the dual queue and performing the duplex printing function; and repeating the converting of the incoming print data, the determining of whether there are the images having the two side pages, the forming of the dual queue, and the scheduling of the printing sequence until the incoming print data is completely received and printed.