Solutions
On the printer's control panel, select > Maintenance > Print Head Alignment to align the print head.
Solutions
If print quality does not improve even after aligning the print head, disable the bidirectional setting.
During bidirectional (or high speed) printing, the print head prints while moving in both directions, and vertical lines may be misaligned. Disabling this setting may slow down printing speed but improve print quality.
Windows
Select Quality Options as the Level setting on the printer driver's Main tab, and then clear High Speed.
Mac OS
Select Print Settings from the print dialog's pop-up menu, and then clear High Speed.