Method for controlling inkjet printing apparatus

A method for controlling an inkjet printing apparatus which performs printing to an elongated printing medium based upon printing data having an image portion and a non-image portion, the inkjet printing apparatus being provided with a printing head having a plurality of nozzles composed of an opening portion from which ink is discharged, an ink chamber communicating with the opening portion to accommodate ink, and a piezoelectric element attached to the ink chamber via a vibrating plate, and a selector for adjusting a time period for performing voltage application to the piezoelectric element, the method comprising:

• a discharging step of performing continuous voltage application to a piezoelectric element of a nozzle to be used with a pulse number equal to or more than two waves per one printing pixel to deform the piezoelectric element, thereby discharging ink in the ink chamber from the opening portion;
• and
• a vibrating step of performing voltage application to the piezoelectric elements of all nozzles with a pulse number of one wave per one printing pixel to deform the piezoelectric elements, thereby imparting only vibrations to the inks for a fixed time period continuously in the ink chambers without discharging the inks, wherein
• voltages to be applied in the discharging step and the vibrating step are fixed and application times of the voltages are controlled by the selector,
• the discharging step is set so as to be performed to the image portion,
• the vibrating step is set so as to be performed to the non-image portion,
• the discharging step and the vibrating step are performed alternately,
• the inkjet printing apparatus performs printing at a page unit,
• the non-image portion includes a margin of a previous page side, a margin of the next page side, and a margin connecting the previous page side and the next page side, and
• in the vibrating step after the discharging step, 10 to 50 vibrations are applied to the piezoelectric element by the piezo actuator.