Ebay sells those rubber roller exit tires, less than $10 for 4 pieces. Search keyword: fi-6130 roller tires. Just bought these because mine are apparently melting due to heat or something and causing the papers to jam up in all directions.
Since the area near to rollers keeps getting hot or staying warm even when not using, I decided to just keep the top unit open/separated when not using.
These two videos helped in the assembly of the unit: