HP OfficeJet Pro 6958, 6968, and 6978 Printhead Stuck on the Right: Carriage Jam Troubleshooting

Question:

I have an HP OfficeJet Pro 6958, 6968, or 6978 printer with the printhead stuck on the right side. I followed the steps to reset the ink bed all the way back, but when I turn the printer on, the carriage slides back, then forward, then back again, and gets stuck on the right side once more. What else should I check?

Answer:

For this HP OfficeJet Pro 6958, 6968, or 6978 carriage jam problem, if you already reset the ink bed or service station area and the carriage still moves left and right before returning to the right side and getting stuck again, the next things I would check are the CR encoder strip and the CR scale/encoder system.

The carriage movement you described is important. When the printer powers on, the carriage usually performs a startup routine. It moves back and forth so the printer can locate the carriage position, check the service station, and confirm that the printhead carriage can travel properly across the rail. If the printer cannot correctly read the carriage position, it may move in one direction, reverse, try again, and then stop with a carriage jam or printhead stuck error.

On these HP OfficeJet Pro models, the printer depends on the carriage return encoder system to know exactly where the printhead carriage is. The clear plastic encoder strip, sometimes called the CR encoder strip or timing strip, runs horizontally behind the carriage. The carriage has an optical sensor that reads tiny marks on this strip. If the strip is dirty, loose, scratched, out of position, or not sitting correctly inside the carriage sensor, the printer may think the carriage is somewhere it is not. That can cause the carriage to slam, hesitate, move back and forth, or park itself incorrectly on the right side.

Here are the main things to inspect:

First, check the CR encoder strip. It is usually a thin, clear plastic strip stretched across the carriage path. It may look almost transparent, so use a flashlight if needed. If there is ink mist, grease, dust, or fingerprints on the strip, the sensor may not be able to read it correctly. Clean it gently with a lint-free cloth slightly dampened with water. Do not use excessive pressure, and do not pull hard on the strip, because it can come off its mounting points or become damaged.

Second, make sure the encoder strip is properly threaded through the carriage sensor. Sometimes during a jam, manual carriage movement, or service station repair, the strip can pop out of the sensor slot on the back of the carriage. When that happens, the printer can no longer track the carriage position, even though the carriage itself may still move. The printer may then drive the carriage incorrectly and stop again on the right side.

Third, inspect both ends of the encoder strip. The strip should be attached securely on both sides and should not be twisted, hanging loose, or stretched at an odd angle. If the strip is not sitting straight across the carriage path, the sensor may misread it.

Fourth, check the CR scale or encoder sensor area on the carriage. If the optical sensor inside the carriage is contaminated with ink spray or paper dust, it may fail to read the strip even if the strip itself is clean. You may not be able to see deep inside the sensor easily, but check for obvious ink buildup or debris around the rear of the carriage where the strip passes through.

Fifth, confirm that the carriage rail and service station are not physically blocking movement. Since you already reset the ink bed, the service station may not be the only issue, but it is still worth checking that the wiper, cap station, or any loose plastic part is not rising too high and catching the bottom of the carriage. A small obstruction on the right side can make the printer appear to reset correctly while powered off, but jam again during startup.

Also check for small pieces of paper, broken plastic tabs, or dried ink buildup around the right-side parking station. A carriage jam does not always mean a large object is blocking the printhead. Sometimes even a small piece of torn paper or a slightly displaced service station part can stop the carriage during the initialization cycle.

If the printer gives a specific error message such as Carriage Jam, Printhead Stuck on the Right, or a similar startup jam warning, that error generally means the printer detected that the carriage could not complete its expected travel or could not confirm its position. In your case, because the carriage moves back and forth before getting stuck again, I would prioritize the CR encoder strip, CR scale alignment, and carriage sensor path before replacing major parts.

A good troubleshooting sequence would be:

1. Turn the printer off and unplug it.

2. Manually move the carriage gently to the center if it can move freely.

3. Inspect the right-side service station for anything raised, loose, or jammed.

4. Locate and clean the CR encoder strip carefully.

5. Make sure the encoder strip is correctly seated through the carriage sensor.

6. Check that the strip is attached on both ends and is not twisted.

7. Move the carriage gently by hand from side to side to feel for resistance.

8. Plug the printer back in and test the startup cycle.

If the carriage still returns to the right and jams after the encoder strip and service station are checked, then the issue may be deeper. Possible causes include a damaged carriage sensor, a cracked carriage assembly, a damaged encoder strip, a failing carriage motor, a worn belt, or a service station that is not resetting correctly even though it appears to be in place.

For this type of problem, I would not immediately assume the printhead itself is bad. A stuck carriage on the right side is often more related to carriage positioning, encoder reading, or mechanical obstruction than to the ink nozzles or printhead electronics.

Addressing printer issues can be a complicated affair because many of these problems are hands-on mechanical issues. Because of that, we are not able to provide remote troubleshooting, suggestions, or support for printer repairs beyond general guidance. 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, we operate on a first-come, first-served basis, so it may take a few weeks before we can accept your printer for drop-off. Our services are structured to repair either a whole printer or specific parts, with instructions on how to proceed. However, we understand that our rates may not be the most economical option for everyone. For that reason, we highly recommend self-help through online research. You can start with YouTube or visit our YouTube channel homepage: BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. Use the search icon next to "About" on the right-hand side of the menu bar to search for specific repair topics. I receive dozens of questions every day asking for videos on specific subjects, and after creating videos for more than nine years, it is difficult to remember every individual video. YouTube's search function is usually the fastest way to find the most relevant video, and it may also suggest helpful videos from other channels.

Thanks again for reaching out and for watching our content. I appreciate your support and hope this gives you a better direction for checking the CR encoder, CR scale, and carriage movement system on your HP OfficeJet Pro printer.