These instructions were taken from a lexmark T64X which is almost the same printer.

They are basically correct and will get the job done but are most likely not exact.

NOTE: The first time I did this the CONFIG MENU did not appear until I hit the right arrow. There also appeared to be some slight differences in the way the menus functioned. Thus, use your common sense and a little exploration and the SELECT and RETURN buttons and the ARROW keys to locate the 'Reset counter' option within the menu.

1. Turn the printer off
2. Enter the Configuration Menu by holding down the SELECT and RETURN buttons while powering on the printer until the display reads PERFORMING SELF TEST. After the self test, the display will read CONFIG MENU
3. Press the right arrow side of the MENU button until MAINTENANCE PAGE COUNT is on the display
4. Press the SELECT button. RESET should be displayed
5. Press the SELECT button again to reset
6. Press the RETURN button to return to the Configuration Menu and press the left arrow side of the MENU button to exit the Configuration Menu 

 NOTE: YOU WILL LIKELY NEED TO LOCATE 'EXIT THE CONFIGURATION MENU' AND SELECT IT TO GET OUT OF THE MENU  and return to the normal interface. If I recall correctly, the RETURN button brought me to the menu where I could arrow over to the 'EXIT CONFIG MENU' selection.

 You will then likely have to use the arrow to toggle over to the " EXIT CONFIGURATION MENU' Selection and press 'SELECT" to exit back to the normal printer menus.