asked Mar 3, 2010 at 10:14am
Hp HP LaserJet 4SI

hp lj 4si damages paper in top output

my hp lj 4si damages the paper if i use the top output. no problem if i use the rear output. if i use the top output, the last +/- inch of the paper is 'wrinkled. Like there are two sets of transport rollers not working at te same speed. Like the last set is running faster then the first set, and the last end of the paper is pushed in faster then the middle and first part. any ideas?
thansk, mark
That would be a worn exit roller. That's the roller visible if you look in from the front of the printer. You have to remove the top assembly and then disassemble it to remove the exit assembly. I don't know if the roller is still available given the age of the printer.
by moe on Mar 3, 2010 at 11:00am Add comment
thanks Moe, I'll try that. first I'll try to clean the rollers (alcohol?) who knows if this helps...
by mbpolak on Mar 4, 2010 at 3:42am Add comment
Alcohol will just dry out the rubber and make it worse. Only thing that would help would be http://www.fixyourownprinter.com/specials/misc/all/S03 If they're not too bad, you can wipe the solution on for several minutes and wipe it dry.
In real bad cases, you would remove the rollers and soak them in the solution for several hours.
by moe on Mar 4, 2010 at 10:33am Add comment
thanks Moe,
how should these rollers look like in good condition? rubber, a bit flexible, or hard plastic?
by mbpolak on Mar 5, 2010 at 12:24am Add comment
The original rollers were hard rubber and you could feel a little bit of texture when you rubbed them. The older they get, the harder and shinier they get. In the end, they can be mistaken for a hard platic roller.
by moe on Mar 5, 2010 at 10:57am Add comment
ok Moe, I opened the output section. I see two types of roller now. One is a metal shaft with rubber rollers on it. These rubber rollers still look like rubber. The shaft is driver by the printer mechanism. Then thete is a second type: two smaller rollers in a plastic frame, and this acen easily be atken out, they are not driven by anything, just run free. These small rollers look just hard plastic. Shoud they also be rubber?
Wish I had an exploded view somewhere, or service info, so I could explain better what i have...
by mbpolak on Mar 5, 2010 at 12:03pm Add comment
It would be the very last set of rollers, I think there were 4, maybe 6 just before the paper hits the top of the printer. They're on a metal shaft.
by moe on Mar 5, 2010 at 12:25pm Add comment
Today I disassembled the whole top section of my printer. Cleaned it, there was soooooo much dust from toner, paper, etc in it. The rubber rollers seemed to be fine, still good rubber quality. Just used water and soap. After assembling the whole lot again. And testing, paper comes out just fine in the top output. No damage. Hope it will stay like this!
Thanks Moe, for the advise.

btw after cleaning all the shafts and gears, I did not use any oil or grease, when I assembled the parts again, because I did not think I should do so. Or should I have used a lubricant? - mbpolak
a little machine oil would be ok. Something like 3 in 1.


by philly5706 on Mar 11, 2010 at 12:32pm Add comment
They don't come with lubricant. Only reason to use it would be if you were getting squeaking noises.
by moe on Mar 11, 2010 at 1:55pm Add comment
thanks Moe,
No squeking noises, so that seems to be fine. Apart from rubber rollers, can you tell me something about service or spare parts for this printer? Much available or almost nothing? Printer is from 1995......
by mbpolak on Mar 12, 2010 at 2:36pm Add comment
HP had pretty much discontinued support for them. Don't even know if they're still producing new OEM toner cartridges. Spare parts are increasingly difficult to obtain. They are mostly aftermarket. I don't have any customers that still use them. Used to take care of quite a few of them. Been a couple of years since I worked on one.
by moe on Mar 12, 2010 at 4:27pm Add comment
Yes, that's something I will need shortly: new toner for my 4Si. They are still available here in the Netherlands. On the second hand market, but "still sealed in platic and catron box". Is there a risk to buy a toner, still selaed and in closed box, but already old? Can a toner be damaged, just from standing in the warehouse?
by mbpolak on Mar 13, 2010 at 1:08am Add comment
Definitely. I recently opened a new sealed OEM toner that was in the box for 15 years. The wiper blade that cleans the drum had totally disintegrated down to the metal holder. Typically, the blade will go bad in 3 years of sitting unused. You can buy aftermarket blades. I regularly replace them in new expired cartridges as a precaution and throw the unused blades away, even though they physically look good.
by moe on Mar 13, 2010 at 9:23am Add comment
ok thanks Moe. Now the next question. If the cartridge sits in my printer, and I print only a couple of pages a month, will the cartridge (wiper blades) also go bad after ?3 years? Will it help if I print some testpages on a regular basis, like once a week?
ps what material is the blade made from?
by mbpolak on Mar 13, 2010 at 12:34pm Add comment
Wiper blades disintegrate with age. They also wear with use since the toner particles it wipes are abrasive. Don't know what the blade formulation is. Rubber, flexible plastic?
by moe on Mar 13, 2010 at 3:28pm Add comment