Epson 1390 White Ink Pump Issue: Why the White Underbase Won't Print

Question:
When connecting the white ink pump to the main line on an Epson 1390, the printer won't print the white underbase. However, if the pump is removed, the print is fine. What could be the problem?

Answer:

The good news is that your printhead itself is not the problem. The issue lies in the ink pressure supply system, specifically with how the white ink pump interacts with your main ink line. When you install the pump, the printer struggles to deliver adequate ink pressure to the printhead, which is why the white underbase isn't printing. Without the pump, ink flow occurs more freely, which explains why you see normal output.

Here are a few areas to check:

1. Ink Pressure & Circulation System

   • White ink is heavier and tends to settle quickly, so the circulation system needs to maintain a steady flow and consistent pressure. If the circulation or pump system cannot maintain adequate ink supply, the white layer won't form.

2. Secondary Tank Setup

   • Adding a secondary buffer tank can stabilize ink flow by maintaining pressure between the pump and the printhead. This is especially important in white ink management systems because clogs and interruptions are more common due to the density of the pigment.

3. Pump Compatibility & Flow Rate

   • Make sure your pump is rated correctly for your printer's system. Some peristaltic pumps, like the 24V Peristaltic Pump for DTF/DTG Printers White Ink Management System (https://bch-youtube-fan-store.myshopify.com/products/24v-peristaltic-pump-for-dtf-dtg-printers-white-ink-management-system), are designed for higher viscosity inks. If your pump's tubing or rollers are restricting flow, pressure can drop before it reaches the printhead.

4. Line Blockage or Air Leaks

   • Double-check that no air is trapped in the main ink line and that fittings are properly sealed. Even a minor leak or bubble can break pressure balance and prevent white ink delivery.

In short, your printhead is fine-it's the ink supply chain that needs attention. Strengthening the circulation system, ensuring consistent ink pressure, and possibly adding a secondary tank should help your white underbase print reliably.

Addressing printer issues can be complicated because of the hands-on nature of the problems. That's why we aren't able to provide remote troubleshooting, step-by-step repair support, or guarantee fixes through messaging. We do, however, provide an in-person evaluation and repair service through our local diagnostic facility (https://bchtechnologies.com/printer-repair-service). Please note that due to high demand, repairs are handled on a first-come, first-served basis, and it may take a few weeks before we can get to your printer. We repair entire printers or specific parts, and provide clear instructions for each process. That said, we understand our rates may not be the most economical, so we also encourage self-help through online research. A great place to start is our YouTube channel homepage (https://youtube.com/@bchtechnologies), where you can search for specific topics using the magnifying glass icon near the "About" tab. With over nine years of video tutorials, it's challenging to recall every upload, but YouTube's search will also surface helpful videos from other creators.

Thank you again for your thoughtful question. We appreciate your patience and continued support of BCH Technologies.