Diagnosis
The presence of faint horizontal lines or "banding" in your text and images indicates that specific nozzles in the print head are either partially obstructed or completely air-locked. While you have already attempted standard head cleanings, these cycles often fail when ink has dried into a crusty residue inside the nozzle plate or when air bubbles have entered the ink lines during a period of inactivity. Because the ET-4850 uses a permanent print head, these clogs can become stubborn. If you have run three or more standard cleanings without improvement, you are likely dealing with a "hard clog" or a vacuum lock. Continuing to run standard cleanings is counterproductive; it floods the maintenance box with waste ink and can actually cause the ink to foam, creating more air bubbles that prevent a consistent flow of ink to the page, which explains why the lines persist despite your efforts.
How to Fix It
To resolve this, you must move beyond standard cleaning and perform a Power Cleaning, which uses a high-pressure pump to force ink through the lines and clear obstructions. Note that this process consumes a significant amount of ink and requires the maintenance box to have sufficient capacity.
- Load a sheet of plain A4 or Letter paper into the rear feed.
- On the printer's home screen, navigate to Settings (the gear icon).
- Select Maintenance from the menu.
- Scroll down and select Power Cleaning.
- The printer will display a warning about ink levels. Confirm that your ink tanks are filled at least one-third full; if they are lower, refill them now to prevent air from being sucked into the lines.
- Select Start and wait for the process to complete. This typically takes 10 to 15 minutes. Do not turn off the printer or open the scanner lid during this time.
- Once finished, do not immediately print a document. Navigate back to Maintenance and select Print Head Nozzle Check.
- Examine the printed pattern. If there are still gaps in the grid lines, turn the printer OFF and let it sit for at least 12 hours. This allows any loosened ink particles to dissolve and air bubbles to settle before the next attempt.
If That Didn't Work
- Manual Print Head Alignment: Sometimes "lines" aren't clogs but misalignment. Go to Settings > Maintenance > Print Head Alignment. Follow the on-screen prompts to select the pattern with the least visible banding. This recalibrates the timing of the nozzle firings.
- Paper Type Mismatch: If you are using heavy cardstock or glossy paper but the printer is set to "Plain Paper," the ink flow will be insufficient, causing gaps. Ensure the settings in your print dialog match the actual media loaded in the tray.
- Wet-Vac Nozzle Flush: For extreme clogs, you can use a specialized print head cleaning kit (containing an ammonia-based solution). Carefully drip 2-3ml of solution onto the print head nozzles using a syringe and a small piece of lint-free cloth to "wick" the ink out from underneath the head.
- Check for Air Bubbles: Open the printer cover and check the translucent ink tubes leading to the print head. If you see large gaps of air in the tubes, a Power Cleaning is the only software fix, but you may need to run it twice (separated by 12 hours) to fully prime the lines.
Heads Up
- Maintenance Box Limit: Power Cleanings fill the maintenance box rapidly. If you receive a "Maintenance Box Full" error, you will need to replace the waste ink pad (Part No: T04D1) before you can perform further cleaning.
- The 12-Hour Rule: Never run more than two Power Cleanings in a 24-hour period. Over-cleaning can overheat the print head and permanently damage the piezoelectric crystals.
- Preventative Printing: To avoid future clogs, print at least one page containing all four colors every week. This keeps the ink moving and prevents the nozzles from drying out.
- Ink Quality: Only use genuine Epson 502 ink. Third-party inks often have different viscosities and surface tensions, which can lead to more frequent clogging and banding on the ET-4850 model.