HP LJ 4050tn jamming

[jenngates]

We have an HPLJ4050tn that is about 8 years old, but I'm not ready to give up on it yet. There seems to be a problem with jamming when it feeds from tray 2. I've swapped out the tray with 2 others and it still jams. I've replaced all the parts that come with the ext. maintenance kit and still issues. The paper consistently jams at the same spot. I don't know the name of the rollers, but it is the set before the paper gets to the transfer roller. There is a grey metal flat piece above it and the paper stops just before that if you're looking down into the well where the toner goes. Here is an image from the printertech page showing the transfer roller in red. I'm talking about the rollers below that. If you look on the left hand side where you can see the screw holding the grey metal piece down, just above that is the roller.

Is it possible to replace those rollers? Or any other ideas on what is causing the jam? It was working fine until about 2 weeks ago, then it was intermittent, and now pretty consistent. I've removed the paper from tray 2 and it works fine from tray 3 but we have to monitor the paper level more.

Thanks,
Jenn

[woodss]

All I think from that post of yours is that the regisration assembly or paper feed assembly located behind the tray 1 assembly could be playing up, if it still does this jam from tray 1 then I think its registration assembly.

there might be a scrap of paper behind the tray 1 assembly at the paper feed assembly, and its clutch could be playing up.

Does it jam when you print from tray 1?

Which 13.x message does it come up on the control panel, this will roughly tell me which sensor is giving the message.

I understand the paper path of this model well.

I have a two 4050N printers around the house one is 7 years old and the garage backup one is same age as yours, these ones have never behaved like yours.

before you go replacing any parts, take off the transfer roller and reinstall it. see if that does anything.

Printing from Tray 2 - HP 4000 / 4050 Service Manual 1999 Hewlett Packard Co. Explains how the system works.
When the Formatter inputs the /PRNT signal to the printer, the Main Motor (M1) starts rotation. When the Main Motor reaches its prescribed speed, the Feed Roller Clutch (CL101) This could be sticky and Tray 2 Pickup Solenoid (SL 101 or SL 103) are turned on. (The Tray 2 Pickup Roller, Tray 2 Feed Roller, Separation Roller, and Feed Rollers are driven by the Main Motor rotation.)

The Tray 2 Pickup Roller, driven by the Pickup Solenoid, rotates once and picks up the paper in the tray. The unnecessary sheets are removed by the Separation Roller and the paper is fed to the pre-feed sensor (PS102).

The CPU monitors the condition of the PS102 for a prescribed period of time. If PS102 does not detect paper within that time, the CPU resumes feeding the paper, maintaining the appropriate between-page distance for continuous printing.

The paper then reaches the Registration Arm, where its skew is corrected. Then it goes through transfer, separation, and fusing stages, passes through the delivery unit, and is delivered to the tray.



These are my thoughts on this.

[cs_steve]

There is a "hidden" roller assembly (you can't see it without removing the MP input assembly) called the paper feed assembly ... this assembly sits behind the MP input assembly and when worn this roller bar can cause the problem you're describing ...

[woodss]

There is a "hidden" roller assembly (you can't see it without removing the MP input assembly) called the paper feed assembly ... this assembly sits behind the MP input assembly and when worn this roller bar can cause the problem you're describing ...

yeah i can think why it could cause the problem, a stuck or worn clutch. CL101, along worn assembly.

its not a could its a certainty.

I believe if that paper feed assembly is replaced that 4050TN will purr like a kitten, like the problem will be solved.
My main 4050N has done 263,000+ pages and its using its orignial paper feed assembly, I hope I never have to replace it.

thx for your backup CS Steve.

[jenngates]

Thanks for all the quick replies. Here are some answers to your questions:
It does not seem to jam from tray one, the manual feed tray.

The last 10 or so entries on the event log are 13.1 50 paper feed 1. paper late jam errors. This are also 13.6 30, 13.20 50, and 13.20 30 errors from about 1200 pages ago.

I've already replaced the transfer roller, but the paper doesn't even get that far.

I think it is that "hidden roller" but I'm not sure where to get a replacement or how to replace it. I only see maintenance kits at printertechs. I do believe this printer has a lot more life it in if I could get this jamming to stop.

Thanks,
Jenn

[woodss]

well then sounds like the hidden roller which is the paper feed assembly and it by sound of it its faulty and needs to be replaced. I have a service and support CD for the model that has a virutal printer, its a flash based document, if you want I can send you that to practice on.

part number for the paper feed assembly is: RG5-2651-000CN

I think your be able too order one though printer techs, or simply ask printer techs to service the printer for you.

All you gotta do is this I give it a go by trying to tell u:
Turn off the printer and ground yourself, take out the toner cartridge and place it in a dark place, failure to do this can damage the drum.

Premlimiary comments, take note how the wires and connectors are located, failure to do this wires can be damaged and you end up with more problems, do not attempt to to this unless your confident.

Firstly take off the formatter cover, and take off the control panel overlay with a screw driver at the sides by prying under the overlay, then it will come off, next place a mini screw driver into the edge of the control panel carefully it will then come off, unplug the connector.

Now take off the front panel from the tray one assembly paper tray dislodge the hinges from the slots becareful not to break it, then slide the front panel to the right, next take note of how take off the tray 1 sensor arm, this is attached to both tray 1 paper tray and the tray 1 pickup assembly, do not take the sensor arm off the paper tray, you have trouble putting it back on, from the shaft this contains the sensor, make note how its aligned. take note there is a spring here, then slide back the paper tray to the bottom it will then come off after this, when you reinstall these parts be sure it moves freely.

Take off the top cover, held down by four screws and a clip near the ID tag, and a arm under the top cover, which you have to dislodge, with pair of pliers, that is connected to the gear train assembly this part dislodges the toner cartridge drive when you change the toner, failure to do this can damage the gear train assembly, it is not nessary to take off the back panel, once this is removed, take off the side covers, the cover of which the power switch is located, take note of the switch this is connected via a power switch rod this has to be aligned again, I usually hold the power switch to the to the rod when I put the cover back on, you have to be careful.

Next once you have all the covers off this is the fun bit, remove 4 inch screws of the top right and left of the tray 1 pickup assembly, then the sliver screw bottom of the feeder cover, this is the cover in front the gear train assembly.

Then disconnect the tray 1 soleniod connector,these are the black cables, besure take note of the wires are routed, the wires can be damaged if the wires are not routed properly or not enough slack, next on the other side of the printer you will see a connector to the engine controller board coming from the tray 1 pickup assembly unplug it, carefully before hand besure you take note how the wires are routed, because the wires can be damaged if not routed properly.

After you do all that, there is four screws that hold the tray 1 assembly in place, unscrew them, now the tray 1 assembly should come out, now at this point you have access to the paper feeder assembly, notice there is screw holes do not put screws in these holes when you replace the paper feed assembly these holes are for to secure the tray 1 pick up assembly.

the two top screws secure the paper feed assembly, before you do this unplug the paper pickup wires, again make note where the connector and how the wires are routed, now once you unscrew the paper feed assembly top screws it should come off easily, before you do this take note how the assembly is aligned, there is a notch, when you take out the old assembly you will see that, you cant mix it up, it come in only one way, thats why the notch is there for.

after you replace the paper feed assembly, reassemble the printer, in reverse of removal, it takes a experiecened tech about 20 to 30 mins to do this, it might take you a hour.

Good luck.

[mixmaster]

This is so cool, as I used to work on these printers a lot back in the day.

After reading this, I'm making a few assumptions:
1. Paper jamming. Probably the paper is flat, not crumpled, right?
2. Error code on the display when the jam occurs. 13.01 or 13.20. You might even have a few 41.5 errors too, possibly.
3. You have replaced the maintenance kit, which needs to be done every 200k page printed. It's 8 years old. So it has seen some use.

Okay, first thing I would do is get a page count on this printer. That's located on the configuration page. Pull tray 2 & 3 out, put paper in tray 1 and use the control panel to print a configuration page (usually found in the Information menu, I believe.)

If you have a printer with over 400k pages, you'll need a paper feed roller assembly and here's why. That component has two paper sensors in it. One is to tell the printer to turn on the laser (registration) and the other is to detect paper from lower paper trays.

As most businesses/people print from the lower trays, the 2nd sensor arm gets A LOT of action. As this arm is made of plastic, it gets worn down over time. It can wear down to the point that when paper hits it, it doesn't push it far enough to interact with the photosensor.

Now, there can be a couple of OTHER things that can contribute to this error, especially if you haven't printed 400k pages through there.

In the paper cassettes, there is the pickup roller. You have to open a little access door to remove or install the pickup roller. I'm assuming that this roller has been replaced as part of the maintenance kit. What I would do, just to test it out, is to remove the black piece that is next to that roller. It's called the torque limiter (I think). Sometimes removing this component allows the paper to move from the tray a little easier. Give that a try.

Lastly, the 4050 paper pickup roller assembly was designed to get at paper jams behind the MP tray. Look at the picture in your original post. In front of the transfer roller, there's a gray metal bar that has a corresponding black plastic piece that mates up with it. (If I could figure out how to highlight the part and repost it I would! Sorry) The black plastic piece can be moved up a little to inspect and remove any bits of paper in that area of that printer.

Sometimes (and I'm not saying you've done this) a user will load a sheet of labels in a lower tray and as the printer pulls these labels, one of them comes off and gets stuck. This affects ALL pages coming from the lower trays. Removing a stuck label here...not fun. You'd have to remove the MP tray pickup assembly.

Sorry for the long response. Hope I've been able to help.

[romeromichael]

The paper jam I am getting on a clients printer is similar, however, it makes it past the transfer roller and when it is about to head into the fuser it stops.

Thanks

[romeromichael]

[QUOTE=woodss;6896]well then sounds like the hidden roller which is the paper feed assembly and it by sound of it its faulty and needs to be replaced. I have a service and support CD for the model that has a virutal printer, its a flash based document, if you want I can send you that to practice on.