Epson 1390 Printhead Cleaning Problem: Why Cleaning Fluid Comes Out of the Adjacent Color Channel

Question

I followed the steps to unclog the printhead on an Epson 1390 printer, and the cleaning process was explained clearly. However, after reassembling the printer, I tested the printhead by using a syringe to inject cleaning liquid into one color channel. Instead of coming out only through that color's nozzles, the liquid came out through the adjacent color channel. What could cause this problem?

Answer

If you inject cleaning liquid into one color channel on an Epson 1390 printhead and the liquid comes out through the adjacent color channel, that usually means the two channels are no longer properly isolated from each other. In a healthy Epson 1390 printhead, each color has its own separate ink path. When you push cleaning fluid into the cyan channel, for example, it should only come out through the cyan nozzles. It should not travel into magenta, yellow, black, or any neighboring channel.

The exact cause depends on how the printhead was cleaned.

If you removed the printhead and took the manifold or internal printhead assembly apart, one possibility is that the core of the printhead was not reassembled securely. The Epson 1390 printhead has very small internal seals and layered ink passages. If the core, manifold, gasket, or sealing surface is not seated correctly, cleaning fluid can leak from one color path into another. Even a small gap can allow fluid to cross over into an adjacent channel. In that case, the issue may not be a clog anymore; it may be a sealing or reassembly problem.

I would first inspect the manifold area, rubber gasket, and seating surface. Make sure the gasket is not pinched, swollen, torn, flattened, misplaced, or contaminated with dried ink or cleaning solution. Also check that the manifold is sitting evenly and that all screws are tightened evenly. If one side is tighter than the other, the seal can become uneven, allowing fluid to escape into a neighboring channel. Be careful not to overtighten the screws, though, because that can crack plastic parts or distort the sealing surface.

If you did not take the printhead itself apart, then the more likely problem is internal printhead damage. This may include printhead delamination, a cracked internal ink channel, damaged bonding between the ink layers, or separation around the nozzle plate. Printhead delamination means the internal layers of the printhead have started separating. Once that happens, the individual color channels may no longer be sealed from each other. Cleaning fluid, ink, or air can then travel sideways into an adjacent color path.

Another common cause is too much syringe pressure during unclogging. Epson printheads are delicate. When a clog is stubborn, it is tempting to push harder with the syringe, but excessive pressure can damage the internal ink channels or separate the laminated layers. Once the internal barrier between two colors is broken, cleaning will not restore it. In fact, adding more pressure may make the problem worse.

Before assuming the printhead is permanently damaged, make sure the liquid is not simply overflowing across the outside of the printhead. Sometimes cleaning fluid comes out of the correct nozzle area, spreads across the bottom surface of the printhead, and appears to be coming from another channel. Also check whether fluid is leaking from the top manifold area and running sideways. External leakage can sometimes look like internal cross-channel leakage.

A good test is to clean the outside of the printhead completely, dry the surface, and then apply very light pressure to one channel at a time. Watch carefully where the first drop appears. If the first fluid appears at the correct nozzle row and then spreads across the surface, the channels may still be separated internally. However, if fluid truly enters one inlet and immediately exits through a neighboring inlet, outlet, or nozzle row, then the internal channels are likely compromised.

If the problem is caused by a loose manifold, bad gasket, or improper reassembly, reseating the parts may fix it. If the problem is caused by delamination or an internal crack, the printhead usually needs to be replaced. Unfortunately, cleaning cannot repair a physically damaged printhead.

Sometimes, when the delamination is minor, the printhead may appear to work for light printing. It may even print normally for a short time if the printer is not used heavily. However, most of the time, a printhead with cross-channel leakage will either mix colors, lose pressure, fail nozzle checks, or stop ejecting ink properly. In more severe cases, the printhead may not print at all because it cannot maintain the correct pressure inside each color channel.

At this point, I would stop forcing cleaning liquid through the printhead. Continued pressure testing can enlarge the damaged area. Instead, inspect the gasket and manifold seating, confirm that each channel is being tested separately, and use only gentle pressure. If the cross-leak remains after reseating everything, the printhead is most likely physically damaged and replacement would be the practical solution.

Addressing printer issues can be a complicated process because many of these problems require hands-on inspection. For that reason, we are not able to provide remote troubleshooting, suggestions, or step-by-step repair support for printer repairs. We do offer an in-person evaluation and repair service through our local diagnostic facility, BCH Technologies Printer Repair Service [https://bchtechnologies.com/printer-repair-service]. Because demand is high, we operate on a first-come, first-served basis, so it may take a few weeks before we can accept your printer for drop-off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. However, we understand that our repair rates may not be the most economical option for everyone. For that reason, we strongly recommend self-help through online research. You can begin by checking YouTube or visiting our YouTube channel homepage, BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. Use the search icon next to "About" on the right-hand side of the menu bar to look for specific repair topics. I receive dozens of questions every day asking about videos for specific problems. Since we have created videos over the past nine years, it is difficult to remember every single one, so YouTube's search function is usually the most efficient way to find the right video. YouTube may also suggest helpful repair videos from other channels.

Thank you again for watching our videos and for taking the time to describe the problem clearly. I hope this helps you determine whether the issue is a gasket/manifold sealing problem or internal printhead damage.