Cleaning the print heads removes any blockages in the print head nozzles. Clean the print heads if printing is faint or a specific color fails to print.
Aligning the print heads corrects the installation positions of the print heads, lessening deviated colors and lines.
By printing a nozzle check pattern, you can check whether the print heads are working properly. Print the pattern if printing becomes faint or a specific color fails to print.
To prevent smudges on the back side of the paper, executed Bottom Plate Cleaning before you execute duplex printing.
http://www.print-digital.info/articles/printer-maintenance.html
