unknown

asked Mar 25, 2006 at 1:16pm
Hp HP LaserJet 4M

LaserJet 4M clicking and image distortion

Hi,

I have previously purchased a main stepper motor from you and installed it with no problems. That was quite a while ago and the printer has been working great since then. Thank you! So I’m hoping that you will be able to help me with this new problem:

I’ve got a LaserJet 4M that has an abnormal clicking sound when feeding the paper. When the printer sheets come out, the image looks as though it is missing or has scrunched a few lines.

The problem started when I installed a new “extra capacity” cartridge (HP branded from Staples). At that time, the problem definitely follow the cartridge: I could swap the cartridges and make the problem come and go. So I returned that cartridge and obtained a regular HP “98A”. The problem went away with the installation of the regular cartridge.

That was a month or two ago. However, the problem seems to be reoccurring. But now it only seems to occur when feeding paper from the manual feed tray; when picking paper from the bottom paper bin, it seems to work ok. When I had the “extra capacity “ cartridge installed, I don’t’ recall the problem being related to any particular paper tray.

The display never shows any error messages.

Please let me know what you think the problem might be and which parts I’d need to purchase to fix it.

Thanks,
Fred
About the only thing that could do that would be the gear that drives the fuser assembly. If you take out the toner cartridge and look at the right rear, you can see the gear on a hinged metal bracket. It starts out life as a white gear, but with time gets yellow and discolored and loses some teeth. You can turn it by moving the large spiral cartridge drive gear on the right side.
by NemTech on Mar 25, 2006 at 2:06pm Add comment
NemTech you did not read his complete post. It only occurs when feeding from the manual feeder so it cannot be the drive gear. I would think that something is not sitting right on the left side of the paper pickup unit. It is there that gears turn when feeding from the manual tray and my quess is one of the gears is just not sitting right. Put your ear to the left side towards the front and toward the top and listen as the paper feeds. That is where the noise should be coming from. If you need instructions on how to remove the paper input unit email me on the link by my name and I will send them to you.
by dmzcompute on Mar 25, 2006 at 3:59pm Add comment
You have to interpret the posts sometimes. If one of those PIU gears were messed up, it just involves the initial paper feed. Most likely, you would get a paper jam. If one of the solenoids were sticking, one of the pickup rollers would turn too many times and probably give a 41.3 error. I factored in his previous posts saying that the cartridge was exacerbating the problem and interpreted that since it was a high capacity reman, it was putting an extra load on the failing fuser drive gear. If that gear was messed up, you would get both the clicking and the missing or scrunched print. The PIU won't cause that. On the part about it works from the MF tray and not the cassette, don't always believe the customer's troubleshooting. How many times have you been led down the wrong path because you listened to a customer?
by NemTech on Mar 25, 2006 at 4:10pm Add comment
But on this board we have to listen to the user until they tell us something different. Plus remember the printer is working only making a clicking noise. He indicates a image issue with some text being scrunched. That would indicate a feed issue before it even gets to the fuser and remember there are not only selenoids there but also gears which move the pickup roller when the selenoid fires. If one of those gears is not sitting right it may stick or it could even be missing a tooth. Since he indicates tray 2 works ok and does not make mention of the image issue with tray 2, I still have to go with the PIU. Also remember if the gear you are directing him to is broken, the printer will jam every time.
by dmzcompute on Mar 25, 2006 at 4:51pm Add comment
There is a simple way to prove which one of us is right. Since the PIU has a separate drive motor, the scrunching would occur at the beginning of the feed. Once the paper hits the fuser, that takes over the feed and if the drive gear was worn, you would get the scrunching at the lower half of the page. Since I've never seen a problem with the gears or motor on any PIU, I have to go with coincidence on it working from the manual tray one or 2 times. Do you not recall the recent incident of the 5100 black page problem where everyone wasted their time listening to the confused poster and it turned out to be the cartridge? You never can trust the poster's input, you have to go with your printer knowledge and gut instinct.
by NemTech on Mar 26, 2006 at 9:33am Add comment
NemTech,

A toner cartridge can't add drag to the fuser coupling gear, as that gear has nothing to do with driving the cartridge.

To quote you:

"I factored in his previous posts saying that the cartridge was exacerbating the problem and interpreted that since it was a high capacity reman, it was putting an extra load on the failing fuser drive gear. If that gear was messed up, you would get both the clicking and the missing or scrunched print"

Also the coupling gear can't cause scrunched print as it has nothing to do with paper motion under the toner cartridge, and the print is put on the paper as it passes under the cartridge. (it's being driven by the transfer roller at that time)

Not to mention that I've never heard a damaged coupling gear cause a clicking sound.

You also stated: "I have to go with coincidence on it working from the manual tray one or 2 times", which indicates you didn't read the thread correctly, the user is having problems only when they feed from the manual tray.

To quote the user: "But now it only seems to occur when feeding paper from the manual feed tray; when picking paper from the bottom paper bin, it seems to work ok"

And in closing, we've fixed many thousands of printers based on the poster's inputs, sometimes we have to ask qualifying questions, but the poster with the "Black pages" was the exeption, not the norm.

One of the things we try to do when posting here is follow a logical troubleshooting sequence based on the original thread, and ask follow up questions so there is a "flow" to the thread. Then later someone with a similar problem can find and read the thread and be led to a solution. When you jump to conclusions regarding the failing component, then it makes it hard for future readers to follow a logical path to fixing your own machine, especially when your conjectures seem to have very little to do with the problem at hand.
by Stephen on Mar 26, 2006 at 5:48pm Add comment
A little more information: I checked the gears on the right side as suggested by NemTech. The gear on the hinged metal bracket is definitely discolored, but I was not able to see any missing teeth on it. Maybe they are loose?? It sounds like the first thing I ought to do is replace this fuser gear.

Today, my wife reported that the problem can also occur when picking paper out of the bottom tray. (So I led you astray on that point - sorry - see below.)

The paper has never jamed in relation to this problem. (In fact, I can't remember the last time I had a paper jam in this printer!)

The missing or scrunched lines have occurred multiple times on the same page and seem to occur anywhere on the page - that is, they are not confined to the top or bottom half.

As nearly as I can tell, the clicking seems to be coming from the rear of the printer - maybe the left side (side opposite from the main drive motor). I'll have to get the printer onto the bench to confirm which side.

Re: "How many times have you been led down the wrong path because you listened to a customer?" I couldn't count the number - I spent my career in computer systems work. It is a bit humiliating to be part of the problem. Guilty as charged. :-)


by unknown on Mar 26, 2006 at 8:56pm Add comment
Which side of the printer the noise comes from is important. If on the left side then it is the PIU and if from the right it could be anything from the main gear unit to the gears on the fuser to even the motor itself. A quick test would be to lift the toner door and then close it. The motor will turn for a few seconds. If the clicking occurs it is the gears on the right side and if no clicking it is the PIU.
by dmzcompute on Mar 27, 2006 at 5:35am Add comment
I'm going to go along with Nemtech's diagnosis since I really can't see it being the PIU. Once the PIU sends the paper into the printer, it's done. Unless both solenoids for the paper pickup and MF rollers were sticking and the rollers continued to turn it wouldn't be affecting paper movement. If the rollers did continue to turn, it would just result in a 41.3 error or a paper jam. I can't see how it could cause the scrunched print. Here's an easy way to check the gear train which I also suspect is causing all the problems. Take the cartridge out, there's a large spiral gear on the right side that drives the cartridge. With your left thumb, push on the gear. That will turn the whole gear train including the fuser and the output rollers. If one of the gears were bad, then you could visually and tactilely see and feel it.
by moe on Mar 27, 2006 at 12:29pm Add comment
Could it be the gear rain not sit properly
by claude on Mar 28, 2006 at 7:03pm Add comment
I ordered the coupling gear, installed it, and that seemed to fix the problem. It is interesting that the old gear, although very discolored, does *not* have any broken or missing teeth. Maybe it was the coupling gear or maybe it just needed to be all taken apart and put back together again. ;-) (In my experience that has fixed a great many mechanical and electrical problems.)

Thank you all for your help and comments in getting this problem resolved for me. It's good to be able to keep the old reliable LJ4 running!

Fred
by unknown on May 12, 2006 at 9:09am Add comment