Why Is My Printer Slamming Left After a Printhead Replacement? A Guide to Syncing Ribbon Cables and Encoder Sensors

Question:

After replacing the printhead and ribbons on my DTG Pro Fusion Model J printer, the printhead suddenly slams into the left side when the printer is powered on. I did not adjust or touch the encoder ribbon or the encoder sensor during the process. Is there some "homing" procedure that needs to be done after replacing the printer ribbons so they sync correctly?

Answer:

Understanding the Problem: Printhead Slamming Left

What you're experiencing is a common problem when the encoder strip (also referred to as the encoder ribbon) is not seated correctly or has been accidentally dislodged during repairs. The encoder strip is a thin, translucent band running behind the printhead. It passes through a small sensor on the back or side of the printhead carriage. This strip helps the printer determine the position of the printhead by allowing the sensor to read movement as the printhead travels side to side.

When that encoder ribbon is missing, dirty, misaligned, or not correctly inserted into the sensor slot on the printhead carriage, the printer cannot "see" where the printhead is. As a result, it often tries to home the carriage and slams it into the side, thinking it's recalibrating, but instead it's just crashing.

Do You Need to Perform a Homing Procedure?

No special manual homing procedure is required after replacing the printhead or the ribbon cables. The printer automatically performs a homing sequence during startup.

However, you must ensure that the encoder ribbon is properly tucked into the optical sensor slot on the back of the printhead carriage. This step is easy to overlook during ribbon or head replacement. Once inserted correctly, the printer will read the strip and begin the homing process automatically upon boot-up.

Here’s what you should do:

1. Power off and unplug the printer.

2. Inspect the encoder strip – Look for any dirt, kinks, or misalignment.

3. Make sure the encoder strip is inserted into the sensor on the printhead carriage – It should slide cleanly through without obstruction.

4. Power on the printer – If the encoder strip is aligned correctly, the printer should perform a proper homing cycle and stop at its designated left/right limits instead of crashing.

This issue is not related to syncing ribbon cables or running any custom synchronization routine. It’s entirely about the mechanical and optical alignment of the encoder system.

Additional Tip:

If the strip appears fine and you’re still getting the slamming issue, double-check the orientation of the printhead ribbon cables. Improper insertion or reversed cables can cause erratic carriage behavior. Look for bent pins or partial connections as well.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. So, we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We offer an in-person evaluation and repair service via our local diagnostic facility (https://bchtechnologies.com/printer-repair-service). Given the high demand, we operate on a first-come, first-served basis. So, it might take a few weeks before we can get your printer to drop it off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. However, we acknowledge that our rates aren't the most economical. Thus, we highly recommend that you resort to self-help via online research. You can start by checking out YouTube or visiting our YouTube channel's homepage (https://youtube.com/@bchtechnologies). Look for specific videos using the search icon next to "About" on the right-hand side of the menu bar. I receive dozens of queries every day asking about videos for specific topics. Having created videos over the past nine years, it's challenging to remember every single one. Therefore, using YouTube's search function would be most efficient. Plus, YouTube might suggest relevant videos from other channels that could assist you.

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