Epson L1800 Printing Only Small Black Lines – Causes and Fixes

Question:
Why does my Epson L1800 only print small black lines instead of the correct image? Before this happened, the clear encoder strip had paint spots on it, and after cleaning, the test page now only shows black streaks.

Answer:

When a printer outputs only small black lines instead of proper images, the problem often points to how the printhead nozzles are being controlled. Epson’s piezoelectric printhead technology uses a set of piezo jets that can manage hundreds of nozzles with only a few signal lines. Essentially, the printer sends electrical pulses that decide which row of nozzles will fire ink at any given time.

If these pulses are disrupted, the nozzles won’t open and close correctly. This can lead to incomplete patterns, long trails of ink, or the appearance of repeated black lines across the page. Based on your description, here are the most likely causes:

1. Printhead Malfunction – The nozzles may be clogged, damaged, or not responding correctly to signals. A partially failing printhead can exhibit precisely the type of streaking you’re seeing.

2. FFC Cable Issues – The flat flexible cables (FFC) that connect the printhead to the mainboard may have damage, poor contact, or contamination. Even a slight misalignment or corrosion on the connector can disrupt nozzle firing signals.

3. Mainboard Driver Problems – The power driver chip, which regulates the pulses sent to the nozzles, may be faulty. If it fails to distribute signals correctly, you’ll see printing errors such as repeating lines or missing patterns.

4. Oscillator Malfunction – The oscillator on the mainboard keeps the signal timing precise. If it malfunctions, the synchronization of nozzle firing is lost, causing erratic output.

Since the issue began after you noticed spots on the clear encoder strip, it’s also worth ensuring that the strip was cleaned carefully. The encoder strip tells the printhead its exact horizontal position. If smudges remain or if it was scratched during cleaning, the head may misalign during printing, contributing to strange, repeating lines.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. For that reason, we’re not able to provide remote troubleshooting, suggestions, or support for printer repairs. We do offer an in-person evaluation and repair service (https://bchtechnologies.com/printer-repair-service) through our local diagnostic facility. Please note that due to high demand, our repairs operate on a first-come, first-served basis, and it may take a few weeks before your printer can be dropped off. Our service can handle both full printer repairs and individual part replacements, with clear instructions for how to proceed. That said, we understand our rates aren’t the most budget-friendly option, so we always encourage self-help research. A great place to start is our YouTube channel’s homepage (https://youtube.com/@bchtechnologies). You can use the search icon next to “About” in the menu bar to locate specific videos, which may cover issues similar to yours.

Thank you once again for sharing your issue with us. Your participation helps strengthen the printing community, and we’re always glad to provide as much insight as possible.