Patent ID: 7712857

Claim:
A printing apparatus for printing on a medium to be printed, comprising: an ink ejection section for intermittently ejecting ink while moving; an encoder for outputting a waveform signal indicating that said ink ejection section has moved by a predetermined distance; and a controller, wherein: in a case where said ink ejection section is to eject said ink during acceleration or deceleration, a section in which said ink ejection section has moved by said predetermined distance immediately prior to a certain section in which said ink ejection section is to move by said predetermined distance is regarded as a first section, a section in which said ink ejection section has moved by said predetermined distance immediately prior to said first section is regarded as a second section, a section in which said ink ejection section has moved by said predetermined distance immediately prior to said second section is regarded as a third section, and said controller calculates a velocity at which said ink ejection section moved in said second section and a velocity at which said ink ejection section moved in said third section based on respective periods in said waveform signal; said controller calculates an acceleration of said ink ejection section based on a difference between said velocity in said second section and said velocity in said third section that have been calculated; said controller calculates a velocity at which said ink ejection section is to move in said certain section based on said acceleration that has been calculated; based on said velocity in said certain section that has been calculated, said controller calculates a reference timing serving as a reference for ejecting said ink from said ink ejection section within a certain period in said waveform signal and as a reference indicating that said ink ejection section is to move in said certain section at a shorter interval than said predetermined distance, and a delay amount which is an amount of time for said ink ejection section to move by a distance (Vs×PGs/Vis)−(Vc×PG/Vi) (wherein Vc is the velocity of said ink ejection section in said certain section, Vs is a reference velocity, PG is a distance between said ink ejection section and said medium, PGs is a reference distance, Vi is an ink ejection velocity, and Vis is a reference ink ejection velocity); and said ink is intermittently ejected from said ink ejection section at a timing delayed by said delay amount from said reference timing.