rohmell

asked Apr 23, 2008 at 5:40pm
Unknown Printer

Laserjet 4000N: transfer roller hold down problem

Hi everyone,
I have a LaserJet 4000N with a transfer roller hold down problem.
My company was going to throw this printer out, but it prints OK except for the printout being slightly darker and smudged (or out of focus?) on the left side of the page. This is being caused by the transfer roller being closer to the paper on one side than the other. The transfer roller does not have a clip to lock down the axle into the paper feed mechanism on the right side. The spring that is on that side allows the roller to rest higher on that side than the other side, where there is a clip that holds it down and retains it under spring tension. I can't tell if the transfer roller is missing a clip, or if the paper feed mechanism is missing a piece of plastic, because I compared this printer to a LaserJet 4's transfer roller, and that one has one clip on the left side, and the right side sorta snaps into place into a kinda 'c' shaped protrusion on the paper feed mechanism.
Is the LaserJet 4000N supposed to have a similar 'c' shaped section for the right side of roller to snap into, or is there an additional piece that goes there? The paper feed mechanism does not look like anything is broken off of it. The service manual does not have close-up pictures of this area, so I can't tell the correct way for the right side of the roller to be held down at the correct height in this printer
I would like to get this printer fully working in the correct manner because it does have the duplexer module with it, and I want to print out all of my service manuals and stuff double sided instead of looking at then as PDFs on the computer screen all the time!
by rohmell on Apr 23, 2008 at 5:43pm Add comment
You will need to replace the paper feed guide assembly. Part number is RG5-2643-160CN. The instructions for removal are not in the service manual but are contained in the 4100 service manaul. Below are the instructions. Not for the faint at heart.

The answer your question above there is nothing on the transfer roller on the right side except for the metal shaft which is held in place by the white plastic holder on the right side.

Paper-feed guide assembly
1 To remove the paper-feed guide assembly:
a Remove the rear right side cover.
b Remove the control panel.
c Remove the top cover.
d Remove the left side cover.
e Remove the front right side cover
f Remove the rear cover/rear output bin.
g Remove the fuser assembly.
h Remove tray 1.
i Remove the tray 1 pickup assembly.
j Remove the right side toner cartridge guide.
k Remove the registration assembly.
l Remove the formatter assembly.
m Remove the printer drive assembly.
n Separate the engine module from the paper-feed module.
o Remove the engine controller board.
2 Remove the plastic main gear cable guide by releasing the three tabs.
3 Loosen the plastic formatter ribbon cable guide.
4 Disconnect the paper-sensor cable.
5 Remove the two self-tapping screws.
6 Carefully remove the paper-feed guide assembly.
Note The engine controller board grounding spring might interfere with removal.
by dmzcompute on Apr 23, 2008 at 5:59pm Add comment
DMZCOMPUTE IS CORRECT ON THE FAINT AT HEART. HAVE DONE A FEW
AFTER TOSSING A 4000 AND A 4100 to parts only status.STEADY AS YOU GO AND BE PATIENT.
STEP BY STEP AND YOU HAVE BECOME AN "E.X.P.E.R.T"....Thats
a drip under pressure. Ha Ha
Geo
by bullshop on Apr 24, 2008 at 6:52am Add comment
Nah, man, that's too much work.
I drilled a small hole in the plastic and used a part of a straightened paper clip to bridge across the broken part and apply downward pressure against the spring.
The roller is now at the correct height and the printing is perfect.
by rohmell on May 4, 2008 at 8:58am Add comment
could you possibly send a picture of this paper clip fix. We have a HP 4350 with a broken holder clip on the spring end of our transfer roller holder just like here causing the transfer roller to sit higher on one end. We don't want to order or replace a whole feeder assembly for such a problem and we get this problem quite often with employees being too rough with toner changing and breaking it in the first place.

A nice cheap quick fix like that would be wonderful. I would love to have a picture of what you did so we may try it. - Anonymous
I don't think it is possible to post pics into the message box.
Send me your email and I can send you a pic.
[email protected]
by rohmell on Nov 19, 2008 at 12:14pm Add comment
I have the same problem. Apparently there is a small tab on the part that sits on top of the spring that breaks easily. The tab also seems to break off if you try removing the part from another printer. I can't find anywhere that sells just this small part and I sure as the heck don't want to replace the entire transfer roller assembly because of this one tiny part. Does anyone have any idea where to buy a replacement for just this part?
by unknown on Jan 23, 2009 at 1:18pm Add comment
I have manufactured a couple of brackets to hold down the spring supports. The whole fix takes about 30 seconds to complete. Testing them now. Made the parts by eyeball measurements. Now the tricky part of accually making a small blue-print to make more. Much easier than a whole dissassembly.
by unknown on Jun 24, 2009 at 4:33pm Add comment
Have you completed the small blue-print to make the brackets to hold down the spring supports for the HP 4000 transfer roller? If you have could you email it to me. Much appreciated. - techigirl
I have a broken plastic stop. Am afraid that epoxy will not hold it and also that putting the transfer roller holder back ON to the spring after the epoxy sets will break the epoxy bond.

Have found a kludge to hold the spring loaded bracket down while the epoxy sets.

after set I will take a U section of a paper clip and reinforce the stop, adding some more epoxy over the clip.

Would like the details of your fix in the event this crashes.

tia - Splork
Sweeeeeet; Worked perfect!! Instead of drilling I heated a paper clip with my lighter; Easier to get in there. I did as listed above and now perfect! Thank you
by aomcopier on Apr 29, 2011 at 4:15pm Add comment
Could you fill me in on the details?? I do not see any posted for the broken plastic stop. - Splork
Can someone email me or send me a link to this fix. I really dont want to tare a 4050 I have down.
by greenghost on Aug 1, 2012 at 4:44am Add comment
I never got a reply. I fixed mine with a lot of difficulty. The stop broken was on the base assembly, not the transfer roller. I used a metal shaft to hold down (wedged in on the left) the transfer roller all the way down to allow me to position the stop back where it belonged atop the "spire" whilst some nearly set epoxy held it in place. after some fussing around it remained in position. A day later with the epoxy fully set I made a hold down brace out of the smaller loop of a paper clip and adjusted the loop to fit over the stop and spire. I actually "sized" it before beginning this.

I applied a fresh epoxy layer over the brace to give added strength. The epoxy would not have held without it. A couple of days later I gently removed the metal shaft and the repair held. It is only stressed when a cartridge is removed.

Tough doing this as there is little room and the shaft adds to the difficulty.

Whatever you use to hold down the transfer roller, it must remain there for days and not "give way" Time to improvise - Splork
Actually when replacing my transfer roller, I accidently broke one side (L) but also found the (R) side was already broken...
Since a repair would actually mean replacing a "sub Chassis" (and a heck of a lot of work) I just hoped for the best, re assembled everything else (just bought a roller replacement kit), and everything works great. I don't know, however, what long term will bring. I printed out a few jobs, and all of them are great. NOW, I WOULDN'T SUGGEST to break off the opposite end that is still holding, but as a last resort??? My situation was if it didn't work when I tried it out, was I most likely would have sent it to the trash.
If someone has any thoughts on this I would appreciate it. As I said, I don't know what to expect long term. Thanks for all your help on this site!!!
Bill
by unknown on Mar 8, 2014 at 2:10pm Add comment
Those holders and springs are there to apply pressure to push the transfer roller against the back of the paper and the imaging drum. Without proper pressure evenly applied across the surface, the image will vary in density from side to side. Having replaced my share of assemblies, I can vouch for the fact it isn't an easy job. - moe
I actually just took small piece of paper folded until it was thick enough to jam it in between the clip on the left until it was at the right level lasted 2 years just had to replace it now.
by unknown on Apr 22, 2014 at 1:21pm Add comment
I was able to look at a working printing to eyeball about how high the plastic U mounts were supposed to be.

I then cut a ~0.25" section off a paper clip, heated the end cherry red using a torch lighter, and just pushed it into the plastic post where the original stop broke off from.

The right side is a far easier to do than the left, but after some trial and error it works. If you mess up the hight, make sure to pull the paper clip piece out before it cools, or you risk breaking off even more plastic. In the same vein, make sure you don't melt the catch on the U piece of plastic when you're checking the height.

Even if you mess up a couple times, there's quite a few different ways you can fashion a small bent wire to melt into the plastic and be at the right height/angle. On the left side, the post was so ruined after so many attempts, I just used a ~0.5" section of paperclip and pushed it in to some plastic farther back, then because it was a bit loose with all the torque from the U bracket, I braced it by taking another bit of paperclip and melting it into another part of the printing frame so that it crossed over the first piece. That way the U bracket pushed up against both of them, which ended up working perfectly.

With trial, error, and some ingenuity it's doable, but it might take longer than 30 seconds.
by ladedah on Oct 24, 2014 at 1:31pm Add comment
Instead of bothering to heat up a paperclip, I just bent a paperclip to get about an inch of one "leg" at a 90 degree angle to the rest of the paperclip. This allowed me to hold on to the clip firmly. Holding both in my hands, I then lined up the leg of the paperclip in the channel or groove on the side of the white U mount that will be nearer to the back of the printer. I then pushed both at the same time back into the slot where the U mount normally goes. This is better than trying to force the paperclip leg down between the U mount and the slot while the U mount is in the slot. The paperclip leg takes up enough room between the U mount and the slot where it is a tight fit. It is not that tight, however, where you can't nudge it up or down to adjust it. I then eyeballed the top of the white U mount to be level with the top of the black U mount on the left side. Then I took a pair of nippers and nipped the paperclip just above the white U mount. Don't worry about trimming the paperclip that close to the top of the U mount as a little paperclip stub won't interfere with anything. Also, I went for as much of the length of the paperclip leg as I could -- down to the printer "floor." While the U mount no longer has a spring to it, it works. I put in my new transfer roller and it prints a perfect page. The clip should stay wedged in there until I chose to remove it. Sure beats the horror stories of replacing the feed assembly. It will take you longer to read this than it will to make the fix. Hope this helps.
by unknown on Jan 22, 2015 at 9:20pm Add comment

Can anyone post any photos of the fix? I broke off that small plastic that holds down the right side white piece where the transfer roller turns? It is such a delicate piece of plastic in the LaserJet 4000TN. Any help or further guidance would be greatly appreciated, especially pictures. Thank in advance.

by velani on May 23, 2016 at 12:33pm Add comment

I've got a similar issue, but nothing appears to be broken.

When I removed the transfer roller, the small plastic part that rests on top the spring on the left side popped off, too, but does not appear to be broken. However, when I put it back in place, it moves freely up and down on the spring, but doesn't "clip" in anywhere to remain in place, so the roller isn't stationary.

I'd consider gluing it in place, but I don't know the actual, proper height/position for it.


Any suggestions?

by jrhender on Dec 7, 2016 at 8:56pm Add comment

I have the same problem as jr hender posted above. Nothing appears broken but left side will not snap in and lock when I turn the black open end of on the left side of the transfer roller down and try to insert it. The little black cap that sits on the top of the left spring will slide off and it does not appear to be broken. Any ideas of problem or easy fix without expensive and time consuming replacement of the whole assembly

by cgsmithhp on Mar 2, 2017 at 10:14pm Add comment

Adding the ability to include pictures would be super helpful

by gertie on Jul 10, 2017 at 5:09pm Add comment

Why is everybody fiddling around with paper clips? This is the BEST fix for a busted retaining plastic piece on the right clip of the transfer roller. It will probably work on the left side for the black clip as well. It's obvious the existing spring is TOO long now. So what we have to do now is craft a spring that is just short enough to work.

First remove the clip. Pull off the existing spring. Find a retractable ballpoint pen, you know the ones with the clicker on the top. Open it up and pull off the spring from the ink refill. Keep in mind the nub underneath the transfer roller clips are of a certain size so you need to make sure to find a pen with a big enough spring to snugly fit over it. Try to check this first before busting open and ruining a pen.

This is where you have to do a bit of trial and error. The objective is to make the clip pop up and give just enough push on the transfer roller so that it hugs the toner drum but not too much.

Snip off a reasonably shorter portion of the spring, try it on the clip and see if it raises it just over the plastic assembly. If it doesn't then it's TOO short and you have to try again. Make it longer. You can make the spring longer by stretching it out slightly with a pair of needle nose pliers.
If it does work out, insert the transfer roller and make sure it's level. Not too high and not too short. Again, there has to be some slight springiness to the roller but not too much. Make sure is it as close to horizontal as possible. Eyeball it all the way across. It should be reasonably even and not lopsided.

Congratulations. You've just saved yourself a ton of trouble of replacing the entire paper feed assembly.

by coban on Mar 28, 2018 at 2:59pm Add comment

So are there any ill effects to NOT pushing down the roller with the clips?

My clips broke, but since the roller stays in place I didnt bother repairing it. The toner cartridge goes right in, and my printouts are perfect.

by Flybye on Apr 26, 2018 at 5:36pm Add comment