HP OfficeJet Pro 6960 Not Printing Black After Replacing the Printhead and Cartridge: Causes and Fixes

Question

I have an HP OfficeJet Pro 6960 printer that will not print black ink. I have already replaced both the black cartridge and the printhead, but the printer still does not print black. The color inks appear to work, but I cannot get any black output. What else should I check, and what can I do to fix the problem?

Answer

Since you have already replaced both the cartridge and the printhead on your HP OfficeJet Pro 6960 and black still does not print, I would not immediately assume that the new printhead is clogged. There are several other parts of the ink-delivery and maintenance system that can cause exactly this symptom.

1. First Determine Whether Black Ink Is Completely Missing

Print a print-quality diagnostic page or another internal test page directly from the printer's control panel.

Look closely at the black section.

If the black section is completely blank while cyan, magenta, and yellow print normally, this usually indicates that black ink is not reaching the nozzles or the black nozzles are not firing.

If you see some black lines but they are broken, faded, or missing in sections, the problem is more likely related to ink starvation, air in the black ink path, clogged nozzles, or insufficient priming.

This distinction is important because a completely blank black channel can point to a different problem than a partially clogged black channel.

2. Check the Black Cartridge Carefully

Even though you replaced the cartridge, the cartridge can still be part of the problem.

Make sure the cartridge is actually supplying ink. If you are using a refilled or aftermarket HP 902-series cartridge, inspect the air vent carefully. A blocked vent can prevent ink from leaving the cartridge.

Also make sure that any shipping tape, protective plastic, or sealing material has been completely removed.

A cartridge may appear full but still fail to supply ink because of:

• A blocked air vent.

• An internal airlock.

• A defective outlet valve.

• Improper refilling.

• A damaged cartridge seal.

• Poor contact between the cartridge and printer.

• A cartridge chip or compatibility issue.

If possible, testing with another known-good black cartridge is helpful. The fact that a cartridge is new does not always mean that it is functioning correctly.

3. Check Whether Black Ink Is Reaching the Printhead

This is especially important because you have already changed the printhead.

The cartridge supplies ink into the printhead through an ink inlet. If that inlet remains dry, replacing the printhead will not solve the problem because the new printhead will simply experience the same lack of ink.

Remove the cartridge and inspect the black ink inlet area on the printhead. You are looking for evidence that black ink is actually reaching the inlet.

If the black inlet remains unusually dry compared with the color channels, you may have an ink-supply problem rather than a printhead problem.

On printers that have been unused for a long time, dried ink can also accumulate around the inlet or cartridge interface and interfere with ink transfer.

4. The Replacement Printhead May Need to Be Primed

A replacement printhead may contain air when installed. The printer's normal initialization process should draw ink into the head, but it does not always do so successfully.

If the black channel contains a large air pocket, repeated cleaning cycles may not immediately restore black printing.

This is why replacing a printhead sometimes appears to make no difference-the original problem may have been ink starvation, and the replacement head is now experiencing the same condition.

Avoid running a large number of cleaning cycles one after another. Each cleaning uses ink and sends ink into the printer's waste-ink system. A few cleaning cycles may be reasonable, but repeatedly running ten or twenty cleanings usually wastes a considerable amount of ink without correcting a mechanical priming problem.

5. Examine the Capping Station and Purge/Pump System

This is one of the most important things to consider when a new printhead still will not print a particular color.

When the printer performs a cleaning cycle, the printhead parks over a rubber sealing area commonly called the capping station. A pump then creates suction and draws ink through the printhead.

If the capping station cannot seal correctly or the pump cannot create enough suction, the printer may fail to prime the black channel.

Possible problems include:

• Dried ink on the capping station.

• A damaged or distorted cap.

• Blocked waste-ink tubing.

• A weak or failed purge pump.

• A disconnected pump tube.

• Heavy ink buildup around the maintenance station.

• A mechanical problem preventing the printhead from parking correctly.

If the printer cannot draw ink through the black nozzles, replacing cartridges and printheads may not help.

This is an area that is often overlooked because the maintenance station is located inside the printer and is not normally visible during regular operation.

6. Check the Electrical Contacts

The printhead contains many individual nozzle circuits. If the electrical connection between the printhead and printer is poor, one ink channel can potentially fail even though the other colors continue printing.

Turn the printer off and disconnect the power before inspecting anything internally.

Check the electrical contacts on the printhead and the corresponding contacts inside the printer.

Look for:

• Ink contamination.

• Bent contacts.

• Corrosion.

• Damaged contact pads.

• Debris.

• Improper seating of the printhead.

Do not aggressively scrape or sand the contacts. They can be damaged very easily.

After reinstalling the printhead, make sure that it is fully seated and that any locking mechanism is completely engaged.

7. Do Not Rule Out a Defective Replacement Printhead

A replacement part can also be defective.

This is particularly worth considering if the replacement printhead was refurbished, used, or obtained from an unknown source.

A printhead contains separate firing circuits for black, cyan, magenta, and yellow. It is therefore possible for the color channels to function while the black channel has an electrical or internal ink-flow problem.

If both the original and replacement printheads produce exactly the same completely blank black result, however, I would investigate the printer itself before purchasing another printhead.

8. Check Whether the Printer Can Produce Black Using Composite Black

Try printing a color image or document rather than a black-only document.

Some HP printers can produce a dark color by combining cyan, magenta, and yellow under certain printing conditions. This is sometimes called composite black.

If the printer can produce a dark gray or black-looking color from the three color cartridges but the actual pigment-black channel remains completely missing on a diagnostic page, that further supports the conclusion that the dedicated black ink channel is not functioning.

A diagnostic page is more useful for troubleshooting than an ordinary document because printer drivers can sometimes substitute colors depending on the selected paper type and print settings.

9. Check the Printer Driver and Paper Settings

This is less likely if black is missing from the printer's own internal test page, but it is still worth mentioning.

If black only disappears when printing from the computer, check:

• Paper type.

• Print quality.

• Grayscale settings.

• Black-ink-only settings.

• Printer driver.

• Application-specific print settings.

Try printing an internal diagnostic page directly from the printer. If black is also missing there, the computer, application, and printer driver are probably not responsible.

10. Consider a Mainboard or Printhead-Drive Circuit Problem

If you have confirmed all of the following:

• The cartridge contains ink.

• The cartridge is venting correctly.

• Black ink reaches the printhead.

• The printhead is properly primed.

• The maintenance station can create suction.

• The electrical contacts are clean and undamaged.

• A second known-good printhead has been tested.

Then the problem may be electrical rather than related to ink flow.

The printer's electronics control the firing pulses sent to the printhead nozzles. A failure in the printhead-driving circuit, carriage electronics, cable connection, or main logic board could prevent the black nozzles from firing.

This is less common than cartridge, ink-flow, printhead, or maintenance-station problems, so I would investigate those possibilities first.

11. Pay Attention to Any Error Message or Error Code

You did not mention an error code in your question. If the printer later displays an error such as an Ink System Failure, printhead problem, incompatible cartridge, or a hexadecimal code beginning with something similar to 0xC19A, write down the exact message and code.

Those errors can significantly change the troubleshooting path.

For example, an ink-system or printhead error suggests that the printer is detecting an electrical, pressure, cartridge, or printhead-related problem rather than simply experiencing clogged nozzles.

The exact error code matters, so it is better to troubleshoot the actual code rather than treating all HP ink-system errors as the same problem.

12. What I Would Check Next on Your HP 6960

Since you have already replaced the printhead and cartridge, my next troubleshooting sequence would be:

1. Print an internal nozzle or print-quality diagnostic page.

2. Confirm whether black is completely blank or only partially missing.

3. Verify that the black cartridge is vented and supplying ink.

4. Check whether black ink is physically reaching the printhead inlet.

5. Inspect the printhead contacts and reinstall the printhead carefully.

6. Run only a limited number of cleaning cycles.

7. Inspect the capping station and purge system for dried ink or loss of suction.

8. If possible, verify the replacement printhead with a known-good cartridge.

9. Only after the ink-delivery and maintenance systems have been ruled out would I begin suspecting an electrical problem with the carriage electronics or printer mainboard.

Because both the cartridge and printhead have already been replaced, I would pay particular attention to ink delivery and the purge/capping station. If the printer cannot pull black ink through the printhead during initialization or cleaning, replacing the printhead alone will not correct the problem.

Addressing printer problems can be complicated because many of the most important diagnostic steps require hands-on inspection. For that reason, we're unable to provide individualized remote troubleshooting, repair guidance, or remote support for printer repairs. We do offer an in-person evaluation and repair service through our local printer diagnostic and repair facility [https://bchtechnologies.com/printer-repair-service]. Because demand is high, the service operates on a first-come, first-served basis, and there may be a wait of several weeks before a printer can be scheduled for drop-off. We can service either an entire printer or certain individual components, and the service page provides instructions for proceeding. We also recognize that professional repair is not always the most economical option, so we strongly encourage self-help and independent online research whenever practical. A good place to begin is YouTube and our BCH Technologies YouTube channel [https://youtube.com/@bchtechnologies]. On our channel homepage, use the search icon located near the "About" section on the right side of the menu bar to search for the particular printer, component, or symptom you are working on. I receive dozens of questions every day asking whether we have a video covering a particular subject. After creating printer-repair videos for more than nine years, it is difficult to remember every video we have published, so searching the channel directly is usually the fastest method. YouTube may also recommend useful videos from other repair channels that address the same issue.

Thank you again for reaching out and for supporting BCH Technologies. I hope these troubleshooting points give you a clearer direction for diagnosing why your HP OfficeJet Pro 6960 is still not producing black ink.