(Cover Off if you don’t already run it with it of anyway)
Wind down the capping stations – to TOTALLY clear the heads.
Push head carriage assembly out of the way.
Clamps off the drain pipes.
Fill the caps with solvent / cleaning fluid to a ‘miniscus’ (fluid dome)
Push heads back into place and VERY carefully re align them whilst..
…wind up the capping station.
Leave over night.
Run a clean cycle or two & test print.
If it’s still patchy – you might have to manually draw ink through with a syringe & clean again.
BIG IMPORTANT NOTE:
The ink levels in the PAIRS (Blk/Cy & Yel/Mag) must be as near to the same as possible or the risk of siphoning is very real.
you need the Roland tool which inserts in to an hole under the machine below the heads, which allows you to wind the heads down. Use some small bulldog clips to clamp the pump line but be careful if they are the plastic pipes as they can clog with ink the rubber ones can as well but don’t seem to be as bad.