Patent ID: 7794034

Claim:
An image formation apparatus for forming a relatively large ink drop by sequentially discharging a plurality of ink drops from an ink drop discharging head, the image formation apparatus comprising: a pressure generating means being configured to generate pressure in an ink chamber to discharge ink drops in response to a drive pulse; and a drive pulse supplying means configured to supply drive pulses to the pressure generating means, the drive pulses being configured to cause the pressure generating means to: contract a volume of the ink chamber without first expanding the volume of the ink chamber to discharge an ink drop, discharge a first ink drop at a first drop speed, discharge at least one intermediate ink drop other than an ink drop that is not followed by any more of the ink drops in a given printing cycle (a last ink drop) at an interval substantially equal to (n+1/2)×Tc but not equal to n×Tc and at an intermediate drop speed, discharge the last ink drop at an interval substantially equal to n×Tc but not equal to (n+1/2)×Tc and at a last drop speed, wherein the first drop speed is faster than the intermediate drop speed, the last drop speed is faster than the first drop speed and the intermediate drop speed, and the last ink drop gathers the at least one intermediate ink drop and subsequently merges with the first ink drop before reaching a print target medium to form the large ink drop, where n is an integer equal to or greater than 1, and Tc represents a resonance cycle of a pressurized ink chamber of the image formation apparatus, the interval being measured from when a corresponding preceding ink drop is discharged.