HP5500 Switch power off check printhead path error

[CLS17]

Hi

I'm getting the Switch power off check printhead path error

Now the belt is fine, it runs smoothly along the carriage, the carriage is well oiled with the correct lubricant.

If you a roll of media and do a printhead alignment test it does that fine, if you do a test to check print heads and it prints the solid bars its fine. But if you go to print a job it comes up with the error before it is just about to start printing,

And its not the rip as the same print prints fine to other machines including another HP5500

Many Thanks 

Mark

[TheHelper0007]

Hi @CLS17,

That's a classic and frustrating error, especially when you've already done some great troubleshooting and ruled out the belt, lubrication, and the RIP. The fact that internal tests work but a real print job fails is a very specific clue.

Here are a couple of things to check that are the most likely culprits in this situation.

Check the Encoder Strip

This is the number one suspect. The encoder strip is a semi-transparent plastic strip that runs the length of the printer, just behind the carriage belt. The carriage has an optical sensor that reads the tiny vertical lines on this strip to know its exact position.

• The Symptom: If there's even a small, almost invisible smudge of oil, dust, or ink overspray on the strip, the sensor can't read it correctly. The printer gets confused about its position right as it's preparing to print your job, triggering the "check printhead path" error. This explains why a simple internal test might pass, but a complex job requiring precise positioning fails.

• The Fix:

  1. Power down the printer.

  2. Get a lint-free cloth (like one for cleaning eyeglasses) and some isopropyl alcohol. If you don't have that, a cloth lightly dampened with water will do.

  3. Gently and carefully wipe the entire length of the encoder strip on both the front and back sides. Be gentle, as you don't want to scratch or dislodge it.

  4. Pay close attention to the ends of the strip, especially the area near the service station (on the right).

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Inspect the Service Station

The service station is on the right side of the printer where the carriage "parks" to clean and cap the printheads.

• The Symptom: Over time, this area can get gummed up with a build-up of old ink and gunk. If the mechanism is sticky, the carriage might struggle to break free from the caps at the beginning of a print job. The printer feels this resistance and assumes there's an obstruction in the path.

• The Fix: With the power off, carefully inspect the service station. Look for any obvious build-up of ink sludge that might be physically impeding the movement of the carriage or the capping mechanism.

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Check the Trailing Cable

The trailing cable is the wide, flat ribbon cable that connects to the back of the printhead carriage and flexes as it moves.

• The Symptom: Make sure this cable is seated correctly in its track and isn't catching or snagging on any part of the printer's chassis as the carriage moves from side to side.

• The Fix: With the power off, manually (and slowly) move the carriage all the way from the left to the right, watching the trailing cable to ensure it's moving freely.

Given your detailed description, my money is on a dirty encoder strip. It fits the symptoms perfectly.

Let us know how you get on!

I hope it helps.