Patent ID: 6402278
Filing Date: 2002-06-11
Classification: B41J,H04N

Abstract:
A method of operating a drop-on-demand multi-tone printing apparatus having a series of channels arranged to receive ink from a source, each channel having a respective ink outlet, each pair of adjacent channels being separated by a respective dividing wall, and each dividing wall being movable in response to a respective wall signal comprising a first pulsed electrical signal to apply pressure pulses to the ink in the respective pair of the channels, whereby ink can be ejected from the outlets and deposited onto a recording medium, the method comprising the steps of:developing for each channel a respective channel signal comprising a second pulsed electrical signal in dependence upon whether ink is to be ejected from that channel, the channel signals for pairs of adjacent channels temporally overlapping each other and not being in phase with each other; and applying to each dividing wall as said wall signal a combination of the respective channel signals developed for the said pair of channels, the wall signals respectively applied to the walls bounding a channel together causing droplet ejection when the channel signal for that channel so requires.