HP Deskjet 3420 Color Inkjet Printer - Manual (Page 61)

calibrating print cartridges
After a print cartridge is replaced, align the print cartridges to ensure the best print
quality. Alignment is performed from the HP Inkjet Utility.
1. Open the HP Inkjet Utility .
2. Select the Calibrate panel.
3. Click the Align button, then follow the onscreen instructions.
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