Digital BW, The Print

I'm having troubles with Carbon-6. 

This is the first time I've tried it. I bought el cheapo refillable carts from eBay and loaded 
them with the ink.

Unfortunately, I've only been able to achieve less than perfect results. No amount of cleaning 
seems to help.

What do you think is causing the problem? Bad carts? Trapped air?

[URL=http://img179.imageshack.us/my.php?
image=bandingbi0.jpg][IMG]http://img179.imageshack.us/img179/8696/bandingbi0.th.jpg[
/IMG][/URL]