Is It Safe to Push Cleaning Fluid Through an HP 6958 Printhead Filter?

Question

I watched your video about extreme bone-dry printhead cleaning and recovering Epson printheads that most people would give up on. I tried cleaning the printhead on my HP OfficeJet 6958 because it is printing blank pages. I pushed cleaning fluid through the filter, and now I am worried that I may have damaged something inside the printhead. Is it bad to clean it this way? Can pressing fluid through the filter ruin the internal parts of the HP printhead?

Answer

In general, it is okay to clean a printhead by pushing cleaning fluid through the filter. That is a method we use here as well. The key is how much pressure is used, what direction the fluid is pushed, what fluid is being used, and whether the printhead is allowed to dry or short electrically before it is reinstalled.

For an HP OfficeJet 6958, the printhead is different from many Epson printheads. Epson printheads are usually piezoelectric, while HP OfficeJet printheads are thermal inkjet printheads. That means HP uses tiny heating elements to create bubbles that fire ink through the nozzles. Because of that design, the printhead can be damaged by overheating, running dry, electrical shorting, or physical contamination inside the nozzle chambers. However, simply pushing cleaning fluid through the filter does not automatically mean the printhead is ruined.

If you pushed fluid gently through the filter and saw liquid coming out of the nozzle plate, that usually means the ink channel is open or partially open. That is often part of the recovery process. However, if you used excessive pressure, there are a few possible risks. Too much pressure can separate internal layers, rupture a seal, force debris deeper into the printhead, or create cross-contamination between color channels. On some printheads, aggressive pressure can also cause fluid to leak into areas where it should not go, especially near the electrical contacts or internal circuitry.

The most important thing is not to reinstall the printhead while it is wet externally, especially near the gold contacts, ribbon cable area, or electronic board. Cleaning fluid or water on the electrical contacts can cause a short when the printer powers on. If that happens, the printer may report printhead-related errors, cartridge errors, or in some cases the printhead may fail completely. Before reinstalling, the printhead should be dried thoroughly on the outside. The nozzle plate can remain internally moist with cleaning solution or ink, but the electronics and contact areas must be dry.

Since your HP 6958 is printing blank pages, there are several possible causes.

The first possibility is that the printhead is still clogged. If the printer sat unused or the ink dried inside the nozzles, a blank page can happen even when the cartridges still contain ink. In this case, cleaning fluid through the filter may help, but one cleaning attempt is not always enough. Dried pigment or old ink can become very stubborn. You may need to soak the printhead, flush gently, let it sit, and repeat the process. Do not use high pressure. Gentle, steady pressure is much safer than forcing the fluid aggressively.

The second possibility is that air is trapped inside the printhead or ink delivery path. After cleaning, a printhead may contain cleaning solution and air instead of ink. If the printhead is reinstalled before ink has properly re-primed the channels, the printer may still print blank pages. Running one or two built-in cleaning cycles may help pull ink back through, but running too many cleaning cycles in a row can waste ink and fill the waste ink system. Give the printer time between cleanings.

The third possibility is cartridge or ink supply failure. The HP OfficeJet 6958 uses ink cartridges that supply ink to the printhead. If the cartridges are empty, dried at the outlet, not venting properly, or not making good contact, the printhead may not receive ink even if the printhead itself is clean. Make sure the cartridges are not depleted and that the ink outlet areas are not blocked. If you are using refilled or aftermarket cartridges, check that the vent is open and that ink can flow from the cartridge.

The fourth possibility is electrical failure in the printhead. If the printer was printing blank pages before the cleaning, the printhead may already have had an internal electrical failure. With thermal printheads, if the firing elements burn out or the internal circuitry fails, flushing will not restore printing. Cleaning can fix clogs, but it cannot repair burned heater elements or damaged electronics. If the printer recognizes the cartridges and printhead but still prints completely blank pages after proper priming, the printhead may be electrically dead.

The fifth possibility is a printer-side problem, not just a printhead problem. The carriage contacts, flex cable, logic board, or firmware communication can also cause printhead issues. If cleaning fluid got onto the contact area and the printer was powered on before it dried, there is also a chance of a short on the printer side. Inspect the printhead contacts and the matching contacts inside the carriage. They should be clean, dry, and free of corrosion, ink residue, or cleaning fluid.

If the printer gives an error code or message, that code is very important. Common HP printhead-related messages include "Printhead Problem," "Problem with Printhead," "Missing or Failed Printhead," "Ink System Failure," or cartridge-related errors. Some HP printers may also show alphanumeric error codes depending on the failure. Since your message mainly describes blank pages and does not mention a specific code, the troubleshooting path starts with ink flow, clogging, priming, and contact inspection. If an error code appears after cleaning, write it down exactly because it can help separate an ink-flow problem from an electrical or recognition problem.

Here is what I would do next. First, remove the printhead and inspect it carefully. Make sure the electrical contacts are completely dry. If there is any moisture around the contacts, let it dry longer. Second, gently blot the nozzle plate on a damp lint-free towel or coffee filter. You should see ink marks from the colors and black if ink is reaching the nozzles. If you see only cleaning fluid or nothing at all, the printhead may not be primed with ink yet. Third, check the cartridges. Make sure they contain ink and that the ink can flow. Fourth, reinstall everything and run a single printhead cleaning cycle from the printer menu. After that, print a nozzle check or print quality diagnostic page. Avoid running many cleanings back-to-back.

If you still get completely blank pages after confirming ink supply and cleaning, the printhead may be damaged or permanently clogged. It does not necessarily mean the act of pushing fluid through the filter ruined it. Many times, the printhead was already severely clogged or electrically weak before the cleaning attempt. The cleaning process simply reveals the condition of the printhead.

So, to answer your main question directly: no, it is not automatically bad to clean and press fluid through the filter. That is an accepted cleaning approach, and we do it here. The danger comes from using too much pressure, using the wrong fluid, letting liquid reach the electronics, reinstalling the printhead while the contacts are wet, or forcing debris deeper into the printhead. Gentle pressure and careful drying are the keys.

Addressing printer issues can be a complicated affair because many of these problems require hands-on testing, inspection, and sometimes repeated trial and error. Because of that, we are not able to provide remote troubleshooting, suggestions, or repair support for individual 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]. Due to high demand, the service is handled on a first-come, first-served basis, so it may take a few weeks before we can accept your printer for drop-off. Our repair options are structured for either whole-printer repair or specific part repair, with instructions provided on how to proceed. However, we understand that our rates may not be the most economical option for every situation. For that reason, we strongly recommend using self-help resources and online research whenever possible. A good place to start is YouTube, including our channel homepage at BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. You can use the search icon next to the "About" tab on the right-hand side of the YouTube channel menu to look for specific topics. I receive dozens of questions every day asking whether we have a video on a particular repair, and after making videos for the past nine years, it is difficult to remember every single one. YouTube's search function is usually the fastest way to find the most relevant video, and it may also suggest helpful videos from other repair channels.

Thanks again for reaching out and for watching the video. I hope this helps you feel a little more confident about what happened during the cleaning process and what to check next on your HP OfficeJet 6958.