Copier/printer operating with interrupts

A copier and/or printer apparatus (10) that supports plural interrupts. When a job is tagged as an interrupt job, the queueing of jobs in a buffer memory (48) switches from FIFO (first in first out) to LIFO in order to process the interrupt job as soon as prescribed. Another job may interrupt the first interrupt job still adhering to the LIFO operation making it the active job as soon as prescribed. When this second interrupt job is completed, the first interrupt job resumes. When the first interrupt job is completed, the job that was interrupted resumes. The original job that was interrupted may have been the first-out job of a FIFO job queue. Interrupting an interrupt is thus possible in an electronic copier and/or printer. The limiting factor is the maximum number of jobs that memory space has been allocated for on power-up of the machine. There thus may be supported interrupting a "normal" job, interrupting a queue of "normal" jobs, proofing a page, and proofing a page within an interrupt job (2 levels of interrupt). With the apparatus configured as a copier/printer, the machine thus supports interrupting a print job with a copy job, interrupting a copy job that interrupted a print job (2 levels of interrupt) and proofing a page within a job that interrupted a copy job that interrupted a print job (3 levels of interrupt).