it only depends on how old is your printer... if it's one year (or more) old than difference is in heads - 'cause Seiko changed some parts on new heads (added tubing...)
hp might have newer firmware....
but basically this are same machines: colorpainter 64 / cs6060 / hp9000
tubing is added cause on older heads ink tube that was connected to head was fixed with head and in that way motion of heads (wile printing) was deforming "o" ring that was preventing air leak. in that way you got air leak / ink starvation in the middle of the print!
but now with this added tubing, motion is not so "hard" like before, and in that way no deformed "o"ring - no air leak - no ink starvation any more...
mmhhhh...I had those "o" rings replaced 2 months ago.
Seiko techs have told me minor improvements have been done, like flat connector that was outside the chain carrying ink lines is now on the inside. This prevents wear away with graze.
Anything elese?
Is the printer now more stable and trouble free operation?
