Hi everyone...new to this forum. I have an ongoing problem with my black ink. I use a bulk system with water-based ink. For months now my black has been dropping of after 2-6" of printing. I have cleaned the damper, cleaned the head, cleaned the line but the problem seems to still persisit. When I switch the black position on the head with another color it works for awhile(like I mentioned above) and then drops off again. I have been rack ing my brain as to what to do next. Please an advice wouls soooooo be appreciated.