A "why did my printer do this" curiosity

[John V.]

Learning is good... Just thought I'd throw this out there..

My Epson 4900 had a completely blocked MK/PK channel right after switching inks. When I had PK loaded up, I printed a nozzle check and everything was good, so something odd happened right after the ink switch. What could cause this?

How I came to notice this blockage...  I went to do a MK print, and all the blacks came out green. I'm curious as to why...

In case that was confusing, these are the events:

1) had PK loaded, printed nozzle check, everything is good
2) switched to MK (I should have ran another check, but didn't)
3) ran MK print that came out with the green
4) printed nozzle check to discover MK totally blocked
5) ran normal cleaning cycle (still blocked) followed by 3 power cleans, finally unblocked.
6) things seem to be back to normal.

??

[Paul2660]

This happens, at times with my 9900, same issue, however more often than not when switching from MK to PK.  Since I had a complete head replacement and new dampers, I have not seen it since.

I believe it's a pressure issue, as it would be next to impossible to have a series of clogs that will take out an entire channel.  The series of cleanings however get it back since you are pushing new ink to the channel. 

Paul

[jferrari]

Since I had a complete head replacement

I remember one time (at band camp) my wife suggested that I, too, do this!