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Self-Explanatory Videos

  1. Jamming during Pick-up: Front View
  2. Debug: Rear View without Duplex Unit

 

Issue Description

Consider the following printer:

  • HP OfficeJet Pro 8000 (A809n)
  • with duplex unit
  • no modifications from factory (ie: no dispenser nor bulk installation)
  • no major problems during its lifetime (nor jamming issues)

Then, suddenly (24hrs ago), it started to jam every time it picks-up a paper. Video 1 exemplifies this malfunction, briefly:

  • cancel button pressed for 3 secs in order to print a test page
  • paper jams just after the main tray (not even entering the duplex unit nor arriving at the printhead)
  • this process can go on forever

Unfortunately, HP no longer provide technical assistance for such model and alternative repair shops are hesitating to accept this service due the lack of spare parts. Therefore, find someone to repair it is not an option.

 

Questions

  1. What is the cause of such failure?
  2. Is it possible to solve it?
  3. In technical terms, how to fix this printer?

 


Notes

  • Brief explanation of video 2: Without the duplex, the pick-up rollers correctly move the paper from the main tray to the rear part. Additionally, if you insert the paper directly from the rear (caution: this can damage your printer), the printing will continue just fine.
  • The pick-up rollers were already cleaned with distilled water (according the procedures of HP Printer Support), however there was no improvement and the malfunction still persist.
  • 1
    There are many possible causes for this. The paper could be sticking together (too much humidify), the rollers could be aging (can't grip and route the paper correctly), there is a component in the printer that is broken. Unfortunately there is no way we can say with certainty what the problem is. As you note the printer is old, and really you need local on-site technicians to inspect the device. All we can give are opinions here. – music2myear Jul 25 '18 at 21:22
  • 2
    This kind of nonsense happens at the end-of-line with any inkjet printer. I have even happen on a $500 inkjet. Switched to laser printer, and lasts over 10 years. theoatmeal.com/comics/printers – cybernard Jul 25 '18 at 23:07
  • 1
    "This kind of nonsense" happens with every device at the end of its line. Yes, Laser printers tend to be better engineered and longer lasting, but they are also mechanically much simpler, and because they have fewer moving parts there are fewer parts to fail. – music2myear Jul 25 '18 at 23:31
  • 1
    @MarkMessa No. Without seeing the printer itself there is no way I've even be able to guess, and as I stated in my first comment, that is only ONE of the POSSIBLE issues. – music2myear Jul 25 '18 at 23:31
  • 1
    The rubber on the paper rollers can dry out (replace rollers). The rollers can get covered in paper dust (clean with isopropyl alcohol), the pads that contact the paper can develop the wrong friction (get coated with paper dust, get friction burns, get sticky crap on them, etc.), a little piece of paper can get stuck inside, an internal part could be worn or bent, tensioners can wear or stretch or get out of adjustment, ... the list is endless. There really isn't a way to answer the question remotely except to keep tossing out guesses. – fixer1234 Jul 26 '18 at 3:44
1

To my experience working as a service engineer there is some piece in the paper path that affected the position of the tray rollers. The abnormal sound of the carriage proves that.

I noticed that that paper is jammed in U form that means that the paper is picked up with a pick-up roller and moved inside to the middle. Then it stops in the paper path but the bottom pick-up roller still moving it forward. That means that something in the middle of the paper path is the wrong position.

To my memory there are so called plastic 'flags' used to detect where each moving part is at every moment. They are moving up and down during the paper move. I saw they are often put in the wrong position and act abnormally providing printer CPU wrong information. As the result cartridge carriage is moving left-right in the wrong time slots (it should be in the most right position when paper reaches it).

Also, from the sound of the carriage I can conclude that it's not moving like it should in full scale. The carriage is driven by a drive with a toothed belt. I saw issues when the belt is damaged and the carriage is slipping on it.

It's not a rubber of the rollers definitely - in the case it would not just move the paper forward.

You definitely need to disassemble the device to fix it. That's all can be said remotely.

| improve this answer | |
  • "I noticed that that paper is jammed in U form that means that the paper is picked up with a pick-up roller" That is correct. – Mark Messa Aug 26 '18 at 15:19
  • "and moved inside to the middle." The paper is blocked in the middle of the U section. Exactly where the 4 plastic rollers from the duplexer unit touch the 4 transport rollers from the printer. Therefore, when I release just a little bit the duplexer (requires a fine adjustment), then the paper is correctly transported to the printheads (50% chance). – Mark Messa Aug 26 '18 at 15:28
  • "there are so called plastic 'flags'" Correct, I'm sure there is at least one of such plastic flags: just after U turn, in the middle of the paper (it is too dark there to be seen in the rear view video). However, the paper never gets there (if the duplexer is correctly attached). Therefore, the error message provided by the printer is tray out of paper instead of paper jammed. On the other side, if the duplexer is released just a little bit (as aforementioned), then sometimes paper jammed error appears (and other types of errors also). – Mark Messa Aug 26 '18 at 15:42
  • "As the result cartridge carriage is moving left-right in the wrong time slots" The printer is currently at an independent technical assistance. I'm gonna ask them to check that. What I do remember right now is that if I remove the duplexer and manually feed the paper into the rear part, you need to perfectly match the timing, the position and the speed in which you insert the paper. Otherwise the printer will prompt an error message. – Mark Messa Aug 26 '18 at 15:50
  • "I saw issues when the belt is damaged and the carriage is slipping on it." If so, I would expect distorted and/or poor quality printings. However, this is not happening. If I feed the paper manually at the rear part (requires fine adjustments), the printer prints just fine. Do you agree? – Mark Messa Aug 26 '18 at 15:56

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