Tech Tip: Understand and Fix Clogged Nozzles

bad-clogged-nozzlesAre you noticing unwanted white lines in your prints?

Do your prints have a strange color cast or appear dull but you aren’t using a filter?

Is your printer printing out blank pages?

Your nozzles are clogged.

No need to panic: we’ve created a step-by-step troubleshooting process you can use to recover your clogged inkjet nozzles.

In this article, we’ll take a look at the causes, symptoms, and solutions for a clogged printhead.

In a hurry to fix your printer? Go straight to the solutions.

Before we look at recovering your nozzles, it’s important to understand what causes clogs in the first place so you can prevent new clogs from forming.

What causes print head nozzles to clog?

The most common causes are:

  1. inactivity
  2. a dusty environment
  3. low humidity

Let’s go through the list.

Inactivity: you’re not printing enough

From our experience, the number one cause of printhead clogs is infrequent usage.

If your printer sits idle for long periods of time until the next job needs to be printed (often weeks to months apart) the ink hasn’t been circulating through the channels. An idle print head will dry up and nozzles will clog.

At the very least, we recommend running a nozzle check every few days to circulate ink through the print head.

Your print environment is dusty

If your print environment is dusty, the dust particles can get inside the printhead,block nozzles, and prevent them from firing.

A dusty printhead is a sure cause of headaches.

If possible, relocate your printer to a non-dusty area. Keep the printer covered when not in use, and cover carpets or other dusty flooring with a dust-free mat under the printer.

Relative humidity is often overlooked

It’s important to check the relative humidity level in your printing environment to ensure that it’s between 40%-60% . When relative humidity is lower than 40%, it’s likely that ink will dry out and cause nozzle clogs.

To raise humidity in your print environment, consider purchasing a non-misting, evaporative humidifier. Also, if the printer is located near a heater or exhaust vent, relocate the printer or the vent to keep dry air flow to a minimum.

Expired inks can damage your printhead

Check your inks to make sure they haven’t expired. Expired inks can turn to sludge (the solution dries up) or contain mold (water-based inks only). Your print head nozzles were not designed to pass sludge and mold through the precision inking system and it may be permanently damaged by old ink.

We recommend never using expired inks.

It’s also important to always store inks properly (cool, dry area out of direct sunlight, and use within a timely manner).

Now that you know what factors cause clogged nozzles, let’s explore the symptoms of clogged nozzles.

Symptoms of clogged nozzles


The 2 main symptoms of clogged nozzles are banding and color shifts in prints.

Let’s talk about banding. What is banding? Banding is unwanted and unexpected horizontal white lines, running the width of your print. The white lines appear where ink should have been laid down, but the corresponding nozzles aren’t firing properly due to a clog.

Another type of banding, dark bands, can be caused by a misaligned print head and is a topic for another time.

Has color shifted dramatically in your prints? Do colors look dull or are they missing completely? For example, your image might have a pink cast throughout, that could mean cyan nozzles are not spraying ink.

The print example above shows samples of both banding and color shifts.

In the most extreme cases of clogged nozzles, blank prints can result.

When your nozzles are all clogged across the board, the printer will print out a blank page.

Knowing the causes and symptoms of printhead clogs is important to prevent them in the future and recognize them if they do occur, but if you’re reading this article, you most likely want to know…

How to fix clogged nozzles


Depending on the severity of the issue, the fix can be as simple as running a nozzle check followed by a head cleaning. Or it can be more complex, such as considering the cost of a new print head vs the cost of buying a new printer (after your warranty has expired).

Here are some general troubleshooting steps to confirm and fix nozzle clogs. Note: it’s important to run manual nozzle checks and cleanings in the steps below. Auto nozzle checks and cleanings are not recommended as they tend to be inaccurate and misleading.

Step-by-step instructions to recover your nozzles

  1. Run a nozzle check to confirm the which color channels have clogged nozzles. If you notice a broken pattern in any of the channels or a missing channel (see the image above) then…
  2. Run a normal/regular head cleaning for the channel pair(s) with clogs.
  3. Run another nozzle check to verify the effect of the cleaning.
  4. If the nozzles are recovered, your job is done. If nozzles are still out, repeat steps 1-3 no more than 3 times. If after the third time the nozzles are still clogged…
  5. Repeat step 4, but this time run a “powerful” head cleaning in place of a normal head cleaning.
  6. Repeat the powerful head cleaning no more than 3 times and print a nozzle check after each cleaning. If powerful head cleaning seems to be making progress in recovering nozzles, follow up with a normal head cleaning at the end to restore the correct ink pressure at the print head.
  7. Are the nozzles still clogged? You have a few options depending on your current warranty status.
  8. Are you in warranty?
    1. Call your printer manufacturer to get a new print head or replace the affected print heads.
  9. Out of warranty?
    1. Consider the cost of a print head replacement (varies by printer but is typically the most expensive part to replace), plus travel and labor costs vs getting a new printer. Recommended
    2. If you are desperate to recover an out-of-warranty printer, you can try puddling the cap. This process is not recommended by Spectraflow or by Epson. Performing this procedure may void your warranty and/or make your printer unrepairable. Consider this a last-ditch effort to keep a printer out of the recycling center.
      1. The process involves pouring distilled water on a paper towel until damp then parking the printhead over it for 4-8 hours.
      2. In theory, the water may unclog the nozzles when given enough time to dissolve the clog. Your mileage may vary and you may have to repeat the puddling  process a few times.

Key Takeaways

When it comes to print head maintenance, be proactive. Your goal is to prevent nozzle clogs before they start (especially if your warranty is almost up).

You can avoid nozzle clogs by regularly using your printer to circulate ink. If you print infrequently, at the very least perform a manual (not auto) nozzle check every 3-5 days to move ink through the entire print head. For regular use, run manual nozzle checks before printing. If you notice breaks in the nozzle check pattern or channels that are completely out, follow the cleaning steps outlined above.

Spectraflow is always available to field your questions about color workflow and other printer-related issues you may encounter! You can contact us here or give us a call at 415-382-8681