| 摘要 |
PURPOSE:To minimize variation in the discharge condition of ink from a nozzle by positioning all liquid paths of a plurality of ink discharge nozzles arranged vertically in a row with respect to a recording head above the ink liquid surface of an ink reservoir section to impart a proper negative pressure to ink in the liquid path. CONSTITUTION:The liquid surface of an ink A in an ink reservoir section 4 is communicated with the outside air while nozzles 16 done therewith. Consequently, a negative pressure of L works on the ink in the highest one of the paths 15 in terms of a head difference. With the consumption of the ink, the ink liquid surface of the ink reservoir section 4 further drops by H, which applies a negative pressure of (L+H) in terms of head difference. Likewise, a negative pressure ranging from M to (M+H) works on the ink in the lowest one of the liquid paths 15. In this manner, proper impartment of the negative pressure makes the meniscus 26 of an ink liquid in the nozzle 16 concave and the retreatment thereof is also held within an appropriate range. Even in the discharging of from the nozzle 16, a specified amount of liquid drops are discharged to ensure a better interruption of the ink discharge thereby maximizing the driving efficiency of an ink discharge driving element 17. |
