First, make sure the nozzle on the Inventor IIS has no filament hanging from the bottom of it. You can simply break this off with the included pliers. Note: When the printer is idle, the motors are off and you can push the platform up or down to get access to the nozzle.
Using the built-in touchscreen, navigate through 'Tools > Settings > Scroll (Down Arrow) > Extruder Calibration'
Once the printer has finished moving around, you'll need to place a single sheet of paper on the print bed.
Next up, click the '-' icon on screen once and wiggle the paper. You will initially feel no resistance. Repeat this process, and as you continue the paper will begin to get caught between the Print bed and the nozzle. Once you feel resistance while wiggling paper back and forth you can continue to the next step.
Continuing on from the previous step, once you feel resistance on the paper, you can remove the paper and click 'Okay' and 'Finish'.
To finish off the extruder calibration, you'll need to perform a 'level'. You can follow the article for this here: http://help.makersempire.com/hardware-help/how-do-i-level-the-bed-on-the-inventor-iis
Tags: Calibrate , calibration , nozzle height , not sticking , too close , not close enough