Controlling drop charge using drop merging during printing

A continuous liquid ejection system comprising:

• a liquid chamber in fluidic communication with a nozzle, the liquid chamber containing liquid under pressure sufficient to eject a liquid jet through the nozzle;
• a drop formation device associated with the liquid jet, the drop forming device being configured to produce a modulation in the liquid jet to selectively cause portions of the liquid jet to break off into one or more pairs of drops traveling along a path, each drop pair separated on average by a drop pair period, each drop pair including a first drop and a second drop in response to input image data, the drop formation device also being configured to produce a modulation in the liquid jet to selectively cause portions of the liquid jet to break off into one or more third drops traveling along the path separated on average by the same drop pair period, the third drop being larger than the first drop and the second drop in response to input image data;
• a charging device including:
• a charge electrode associated with the liquid jet;
• and
• a source of varying electrical potential between the charge electrode and the liquid jet, the source of varying electrical potential providing a waveform, the waveform including a period that is equal to the drop pair period of formation of the drop pairs or the third drops, the waveform including a first distinct voltage state and a second distinct voltage state, the charging waveform being independent of input image data, the charging device being synchronized with the drop formation device to produce a first charge state on the first drop of the drop pair, a second charge state on the second drop of the drop pair, and a third charge state on the third drop;
• and
• a drop merging mechanism configured to cause the first drop and the second drop of the drop pair to combine with each other to form a fourth drop having a fourth charge state;
• and
• a deflection device configured to cause the third drop to begin traveling along a first trajectory and cause the fourth drop to begin traveling along a second trajectory, the first and second trajectories being different when compared to each other.