| 摘要 |
PURPOSE: To provide a method and apparatus for preliminarily investigating the exhaustion state of the ink in the storage part of an ink jet printing head. CONSTITUTION: The pulses corresponding to bits to be printed are serially sent to a counter 54 from a printing bit generator 50 to be counted. Each of the pulses corresponds to one ink liquid droplet discharged from each of the nozzles of a printing head 33. The number (m) of ink liquid droplets equal to the amt. of ink evaporated from a cartridge 15 within a prescribed time and the number N of ink liquid droplets discharged from the printing head equal to the ink amt. held within a storage part are stored in a memory 56. A clock circuit 58 sends one pulse to a central processor 45 at each time when the prescribed time is elapsed to send the number (m) of ink liquid droplets to an addition circuit 60 on the basis of the pulse. When the sum (m+Px) thereof is equal to N, a comparator 65 energizes a display circuit 67 to issue an alarm for the replacement of an ink cartridge. |
