Kyocera has introduced aqueous ink jet printhead suitable for high speed single pass printing by making use of 2,656 nozzles aligned in 108 mm, from which 12 pl drop can be ejected at 30 kHz. In order to improve their productivity, the authors have been studying on the design through the steps as follows.Firstly, acoustic period of a drop ejector is shortened by reduction in pressurizing cavity area, or bend mode actuator compliance. This modification worked as intended but made the drop ejection speed slower due to decrease in cavity volume deformation. In order to compensate the pressure fall, drive voltage rise to 109% of original design.Secondly, for higher flow rate inside the manifold, they are expanded in cross sectional area, not in their thickness but by their depth particularly, or dimension in perpendicular direction to print width horizontally. It is due to restriction for the expansion in height, not to extend descender together that has influence on acoustic period. As a result, cross sectional area of the manifolds are increased 14 % from original design by 5 mm expansion of printhead dimension in depth.By implementation of all these design changes, newly developed printhead can be driven up to 40 kHz with 12 pl drop from same number of nozzles as original model. In spite of 32% higher flow rate from the original model, the developed model show stable printing performance up to 1,680 mm/s