Hi TK8. Epson printers, including XP-970, contain a permanent print head that needs to be charged with all colors to work. Even when you are printing black text only, a small amount of color ink is used to keep the print head charged, preventing air bubbles from entering. Air bubbles can damage the print head. Additionally, the ISO print speed of this printer is 8.5 ppm in black or 8.0 ppm in color. For more information, please visit the official Epson Support website. Regards, Bobby - The Epson Team.