HP 4L printer jamming near feed roller

[hapesp]

My printer has worked perfectly and wonderfully for years.  Suddenly the paper jams at the feed roller wtih every attempt to print, regardless of paper type, regardless of whether I am using automatic or manual feed.  This is what happens: the feed roller catches the paper - and then the paper jams. 

I am using the same paper I used prior to the constant jamming, so the paper is not the issue.

I have been using the same software and operating system (Windows XP) for years; these are not the cause.

Just now I ran a few test pages on automatic feed.  The first time, the page printed just fine.  I tried again immediately afterwards - the second time it jammed.

I do not see any pieces of paper, small or large, caught in the feed roller.   What is the cause of the problem? The solution?  Please tell me there is one - I absolutely love this printer and do not want to part with it.

Thanks for the help!

[Castor]

Hi there,

Most of the time the reason for problems like this is dust. The best way to improve the paper feed is to clean the feed roller with a slightly damped cloth. This will remove the dust and will improve the paper pick.

Please let me know if this helps.

[hapesp]

Hi,

Thank you for your reply and suggestion.  I wiped the roller as best as I could.  Unfortunately the paper is still jamming.  In fact, now the jam happens sooner, when less of the paper has been fed into the printer.  What other reasons might explain this problem, and what other solutions might solve it?

Thanks for the additional help, if you can provide it!

[worldbeat99]

I just printed about 100 pages on my 4L.  It was fine.  Then that terrible

jamming raquet started.  I cleared the paper jam, and stuff.

Still makes noise.  I hope HP has a solution.  Has worked great for years.

[rherber1]

Like many others I have enjoyed long and faithful service from my old HP 4L. Last night  mine suddenly started to jam just where the D shaped rubber roller is situated at the front. Luckily, there were no horrible grinding noises accompanying the symptom.

I looked for possible solutions on-line and in forums such as this one and all I could find which  appeared to be the likely cause was that it would need a new paper pick-up feed assembly fitted - something I wasn't likely to find off the shelf in Australia. Today I decided to pull the printer apart and see what the problem was. After experimenting and finding all the tricks to dissassembly I finally had the beast pulled completely to pieces - right down to the main PCB. I might add that the insides were very clean with only a slight amount of paper dust evident on rubber rollers etc. In fact all the rubber surfaces looked in extremely good condotion without any polished or hardened surfaces. A quick wipe with a cloth soaked in isopropanol soon had all these surfaces back in pristine condition. There was nothing which jumped out at me saying "the fault is here". So I had to look at everything associated with the pick-up and the item which looked suspicious was the D roller detent solenoid latch.

I removed the solenoid which has the detent to stop the D shaped roller when it has done its job and when I operated the armature I noted that it stuck to the pole face of the coil and only after some considerable delay was the helical spring able to restore it to its normal condition. Inspection of the armature revealed that it was coated with brown sticky gunk and it was this compound which was causing the aberrant operation. I removed the armature and cleaned both the pole face and the armature with isopropanol and when reassembled the solenoid operated perfectly without sticking. Since this solenoid is intimately associated with the paper pick-up roller I figured that any sticking of the detent armature would play havoc with this function. And so it proved to be the case when I finally reassembled the printer. I ran off a dozen or so prints in quick succession and the printer functioned without a hitch.

While I had the main board out I checked all the electro caps for ESR and found there were 5 which needed replacing. This should see the printer out for another 13 years or so :-)

So, if your HP 4L printer isn't exhibiting and grinding noises and has been performing well but suddenly begins to jam just where the D shaped paper pick-up roller is, then it might be as simple as cleaning the armature and pole face on the detent latch solenoid. Unfortunately, the main board has to be removed in order to get to it.

[-JohnB-]

This seems to be a commercial product. For the best chance at finding a solution I would suggest posting in the forum for HP Business Support!

You can find the Commercial Laserjet board here:
http://h30499.www3.hp.com/t5/Printers-LaserJet/bd-p/bsc-413

Best of Luck!

[rherber1]

John B wrote;

This seems to be a commercial product. For the best chance at finding a solution I would suggest posting in the forum for HP Business Support!

Not sure whether this is in reply to my post. If it is I don't see the relevance so perhaps some explanation is in order :-)

[rherber1]

Addendum to my earlier post on this issue:

After the repair I was printing a long run of pages which caused the printer to get reasonably warm when the same symptom occurred once more. Exactly the same fault where the corner of the paper would be picked up and then the jam was just as the paper was about to be fed via the main feed roller. This time I noticed that the D pick-up roller appeared not to be in the position I expected, ie. it was not latched by the detent after completing its job.

I dismantled the printer and removed the complete D roller pick-up mechanism and discovered there was a similar magnet latching system in this unit associated with the plastic gear mechanism which drives the D roller. Manual operation of the armature showed that it was sticking to the magnet pole face and the helical spring took some time to return it to its unoperated position. Dismantling the armature (helical spring) revealed there was a rectangular shaped area of brown sticky material on the armature and the yoke pole faces where they came into contact when the coil was energised.

Given the identical size and shape of the sticky patch I realised that this was most likely the remnants of the original material the manufacturer used to provide a residual air gap. Instead of using a brass stud (or other non magnetic material) they probably used an adhesived backed tape similar to Sellotape. Over the years of compression during operation, combined with temperature and humidity, the tape had become degraded and just left the adhesive material behind thus causing the armature to stick to the pole face.

After cleaning the material off the affected areas and reassembling the printer it has printed several hundred more pages without failure. I did not bother to provide new residual air gaps on either the first or second  armatures and it appears to not be a problem.

[JohnHopf]

Wow!  This is EXACTLY what I was looking for !

Any quick tips on how disassemble this thing down to the main board as you say must be done?

I have worked on other HP printers, and YES they have some tricks to them !

Kinda getting lazy and don't really want to spend the time figuring how to disassemble THIS one :-)

[JohnHopf]

I found the sevice maual online, and am working on it...