The Roland XR-640 and XF-640 are workhorses, and almost every print quality complaint on them traces back to one of six causes. Work through this list in order – cheapest first – and you will fix most faults without calling a technician.
Start With the Right Head
Both the XR-640 and the XF-640 use the Epson DX6 printhead, Roland part number 6701409010 – 1,440 nozzles arranged in 8 rows of 180, native 360 dpi, variable drop from 1.5 pl up to 21 pl, typical firing frequency 8 kHz.
DX6 and DX7 are not interchangeable. They are different generations with different nozzle plates and different drive requirements. Machines in the same family – VS, RA, RE, RF, XT, EJ, RT, BN-20 – also use the DX6, so the part number is shared, but always confirm against your serial number before ordering.
DX6 heads also require DX6 valve dampers. Fitting a standard damper to a DX6 machine is a common and avoidable cause of ink starvation.
Symptom Table
| Symptom | Most likely cause | What to do |
|---|---|---|
| Thin horizontal bands in solid fills | Clogged or deflected nozzles; worn wiper | Nozzle check, clean wiper and cap, then a normal cleaning cycle |
| One colour missing entirely | Air in the ink line, damaged damper, or a dead channel | Check the damper for bubbles, purge the line, test the head cable |
| Vertical lines or random offset | Dirty encoder strip, worn feed roller, wrong media feed calibration | Clean the encoder strip, re-run feed calibration |
| Colour shift across the print | Partial nozzle dropout in one channel; ink settling | Recover the channel with cleaning before touching the ICC profile |
| Ink smearing at the edges | Head height too low, media cockling, static | Raise head height, check heater settings, check the media path |
| Fine spray or mist on the media | Deflected nozzles, dirty head face, wrong vacuum | Clean the head face, check the wiper, reduce vacuum |
Rule of thumb: if the problem is regular and repeats down the whole print, it is mechanical (feed, encoder, encoder strip). If it is irregular and follows the head, it is a nozzle or ink delivery problem.
The Cheap Fixes, In Order
- Nozzle check and one cleaning cycle. Never run five cleaning cycles in a row – you waste ink and can flood the cap.
- Wiper blade. A worn wiper leaves a film of ink on the head face, which is exactly what produces spray and deflection.
- Cap top. Check the seal. A cap that leaks means the head dries out overnight and you start every morning with missing nozzles.
- Dampers. Look for air bubbles. On a DX6 machine, always fit DX6 valve dampers.
- Encoder strip. Clean it, then inspect it against the light for scratches. A scratched strip cannot be cleaned – it has to be replaced.
- Head cables. When a new head is fitted, replace the head data cables at the same time. Fitting a new head on worn cables is one of the most common causes of premature failure.
When It Really Is the Head
A head is genuinely finished when the same nozzles fail to recover after cleaning, the cap and wiper have been replaced, the dampers have been checked, and the fault has been confirmed on a second nozzle check. Head strikes – a corner of media lifting into the head – are the usual cause of sudden, permanent damage.
FAQ
How do I know if my Roland needs a DX6 or a DX7?
Check the part number on the head and the printer’s service documentation. The XR-640 and XF-640 take the DX6 (6701409010). Never fit a DX7 into a DX6 machine or the reverse.
Why does my print lose quality after a head replacement?
Usually calibration: head rank not entered, alignment not re-run, or old head cables left in place. See our guide to printhead replacement.
How clean should the wiper be?
Clean it every week, replace it every three to six months of regular production.
Parts for the XR-640 and XF-640
We supply printheads, dampers, cap tops, wiper blades and encoder strips for the Roland XR-640, XF-640 and the rest of the DX6 family. Send us your model and serial number via our contact form and we will confirm compatibility before you buy.