Abstract: A system for detecting an ink consumption in an ink jet recording device comprises a non-volatile memory for storing an accumulated amount of ink consumption, update section for incrementing the stored amount by a new amount of ink consumption, a comparator for comparing the accumulated amount against a variable reference amount, and a display section for displaying the accumulated amount of ink consumption or a residual amount of ink in the ink jet recording device. The recorded amount includes total ink consumption by nozzle cleaning, nozzle suction and ink discharge.

Abstract: In an inkjet printer, print image data indicating a pattern of ejection and non-ejection nozzles is produced from print data received from a host computer and the print image data is searched in blocks for an effective block including data indicating at least one ejection nozzle to count effective blocks, wherein a block has a predetermined size. Ink consumption caused by a print operation is detected based on a count of the effective blocks.