HP Designjet T3500 Production eMFP - Manual (Page 63)

Load a roll onto the spindle
1. Open the roll cover.
2. Remove the black end of the spindle from the printer, then the blue end.
CAUTION: Be sure to remove the black end first. Removing the blue end first could damage the black
end.
WARNING! Do not insert your fingers into the spindle supports during the removal process.
ENWW Load a roll onto the spindle 53