Troubleshooting Ink Flow and Mixing Issues in an Epson L805 Modified DTF Printer

Customer Question:

I recently introduced an ink splitter into the return pipe of my modified Epson L805 DTF printer to regulate pressure. Initially, the nozzles performed flawlessly, but I observed two issues:

1. When performing a head cleaning while the pump is off, the white ink going to the dampers comes from the return pipe rather than the main white ink tank. I suspect the pump locks ink movement from the white tank when the pump is off. Should I perform head cleaning while the pump is running?

2. Before introducing the ink splitter, I noticed that white ink mixed with cyan in the return pipe when the circulation pump was on. I even observed cyan ink appearing in the white dampers at the LC (light cyan) position. My nozzle checks became perfect after switching to standard L805 dampers and installing the ink splitter. However, I later observed a layer of cyan floating on top of the white ink in the tank, even though there were no traces of cyan in the dampers or the ink splitter. Could this be residual cyan from previous contamination? Is this a common issue?

Answer:

Thank you for contacting us. I sincerely apologize for the delay in responding to your inquiry. I understand that printer issues are always urgent, and I want to give you a detailed and thoughtful response. At BCH Technologies, we truly appreciate your engagement and support, primarily through our YouTube channel (https://youtube.com/@bchtechnologies). Your feedback is invaluable in helping us refine our expertise and develop better solutions.

Now, let’s go over the issues you’re experiencing:

Should You Perform Head Cleaning While the Pump is On?

Your description shows that when the pump is off, it prevents ink from flowing freely from the main white ink tank, possibly acting as a check valve. This would explain why the ink drawn during head cleaning comes from the return pipe rather than the tank.

Recommendation: It is generally best to perform a head cleaning while the pump is running. This ensures a steady flow of ink from the tank and prevents the system from pulling ink from unintended sources, such as the return line. You can test this by manually turning on the pump during a cleaning cycle and observing whether ink flows more consistently from the main tank.

Cyan Ink Mixing into the White Tank

Before introducing the ink splitter, you initially observed cyan ink contamination in the return pipe and white dampers. After switching to usual L805 dampers and adding the splitter, your nozzle checks improved, but later, you noticed a layer of cyan floating on top of the white ink in the tank, even though no cyan was present in the dampers or the splitter. Here are some possible explanations:

1. Residual Ink Contamination: Since you didn’t completely dispose of the previously mixed ink, a small amount of residual cyan could still be in the system. Over time, lighter ink components like cyan can separate and float to the top of denser white ink, creating the layering effect you observed.

2. Micro Backflow in the System: Even if cyan isn’t visibly mixing in the dampers or return lines, minor fluctuations in pressure may be causing small amounts of cyan to seep into the tank. This could happen if the ink system isn’t fully sealed or if pressure imbalances occur when the pump cycles on and off.

3. Ink Density Differences: White ink contains heavy titanium dioxide pigments, which tend to settle at the bottom, whereas cyan ink has lower density and can float when mixed. Since you siphoned the bottom layer and only partially disposed of the mixed ink, any remaining traces of cyan could have resurfaced over time.

Solutions:

• Agitate the White Ink Tank: Gently stirring or shaking the tank can help reintegrate any minor ink separation.

• Completely Purge and Refill: If cyan contamination continues, the tank may need to be emptied, cleaned, and refilled with fresh white ink.
  

• Check for Pressure Imbalances: Ensure that no leaks or improper pressure levels are causing unintended ink movement within the system.

Your modifications have significantly improved performance, but residual contamination from earlier mixing may still affect your results. If the issue persists, carefully monitoring how ink moves during pump cycles might provide further insights.

Addressing printer issues can be complex, mainly since troubleshooting often requires hands-on adjustments. We cannot offer remote troubleshooting or repair support, but we provide in-person evaluations at our BCH Technologies repair facility (https://bchtechnologies.com/printer-repair-service). Due to high demand, we operate on a first-come, first-served basis, and it may take a few weeks before we can accept a drop-off. Our repair services cover both complete printers and specific parts, with clear guidance on the process. However, we understand that our rates may not be the most cost-effective option. We highly encourage self-research using online resources like our YouTube channel (https://youtube.com/@bchtechnologies). You can use the search icon on our channel’s homepage, next to the "About" section to find specific troubleshooting videos.

Thank you again for your support and patience in resolving this issue. Let me know if you need any further clarification.