... I put your query to my digital friend - Grok.... here is what he said:
Yes, a dirty or worn encoder strip (or its sensor) is a very common cause of exactly these symptoms on HP Latex printers like the 560.
Quick Background on the Errors
- 86:01 → Typically a scan axis / carriage movement issue (obstruction, friction, belt, motor, or encoder problems). Replacing the scan axis motor fixed the initial error but didn't resolve everything, which is common if the encoder wasn't addressed.
- 42:03 → Related to the scan-axis motor (current limit exceeded, often due to friction, obstruction, or positioning/feedback errors). Mid-print occurrences point to intermittent issues during movement.
"Stepping" Prints
The "steps over and up" artifact (clean in sections but shifts stepwise across the print) is classic for
scan-axis positioning errors. The printer loses accurate tracking of the carriage position during passes, causing it to misalign on subsequent movements. This is frequently tied to the
encoder strip (the long coded strip the carriage reads for position) or the encoder sensor on the carriage.
Why Encoder Issues Fit Perfectly
- Dirty encoder strip/sensor: Dust, ink mist, or residue interferes with optical reading → erratic positioning, stepping/jagged artifacts, and intermittent 42:03/86:01 errors. Very common after motor work (disturbing things can stir up debris).
- Worn/damaged strip: Scratches, faded marks, or debris buildup cause the same. If the strip has blotches, stains, or visible wear, it won't read cleanly.
- Carriage moves freely by hand with normal drag → rules out major mechanical jams or tight bearings in many cases, but doesn't rule out encoder feedback problems or subtle friction that shows under powered movement/printing speeds.
Next Steps to Test/Try (in order)
- Clean the encoder strip thoroughly(top priority):
- Power off/unplug the printer.
- Open the window.
- Use a lint-free cloth (like microfiber or coffee filter) dampened with plain water or isopropyl alcohol/water mix (avoid pure solvents that can erase the markings). Gently wipe the strip, especially the upper edge where the lines are. Move the carriage by hand to clean the full length. Do not scrub hard.
- Also clean the encoder sensor (small optical reader on the carriage) if accessible.
- Many users report this fixes stepping and 42:03 errors.
- Clean and lubricate the slider rod(s)(carriage rails):
- Wipe clean, then apply the recommended HP lubricant (or equivalent) sparingly. This reduces friction that can overload the motor or cause positioning slip.
- Check the carriage belt:
- Look for wear, fraying, proper tension, and that it's seated correctly on pulleys. A slipping or worn belt can cause stepping after motor replacement.
- Run diagnostics/calibrations:
- Check for firmware updates.
- Run any scan-axis or carriage tests if available in the service menu.
- Print a nozzle check or alignment pattern to see the stepping clearly.
- If cleaning doesn't fix it:
- Replace the encoder strip (common part, not too expensive).
- Less likely but possible: encoder sensor on carriage, or issue with the new scan axis motor (wiring, installation, or defective replacement).
The fact that you replaced the motor already and symptoms persist strongly suggests the encoder system or related friction/feedback. Start with a good cleaning — it's free and fixes a huge percentage of these cases.
If you can describe or share more details from the image (e.g., how consistent the stepping is, spacing of steps), that could narrow it further. Good luck getting it running smoothly!
