Digital printing system which retains recent files for rapid output

The present invention relates to a digital printing apparatus, particularly a relatively high-speed printing apparatus which is shared among numerous independent users. A printing system, available to a population of users on a network, checks whether files in recently-received print jobs are identical to files which have been previously decomposed or rasterized within a particular time frame prior to the submission of the job. If it is detected that a file to be printed in a recently-submitted job is identical to a file which has already been rasterized with the rasterized image available in memory, the system substitutes the already-rasterized file for the file submitted with the job, thus saving the time and resources for rasterizing the file in the recently-submitted job.