asked Oct 10, 2000 at 7:15pm
Unknown Printer

4si Input Jam.

I recently purchased a used Laserjet 4si. I was able to print several pages, but have begun experiencing a jam condition. The paper loads
into the printer okay, but gets hung up in an accordion type position underneath the pivoting metal plate in the front of the printer. There are two plates, and the paper is jammed underneath the bottom one, just before it makes it to the next roller assembly.

Sorry, I don't know the technical names of the parts, but I hope my description is enough to tell you what I'm getting at.

Any ideas?

That's the registration assembly. Assuming there are no bits of paper or label in the area, check that the black plastic coating on it is smooth and not rippled.
by moe on Oct 10, 2000 at 8:07pm Add comment
It's mostly smooth, but it does have a few blemishes in it and a few smallish ripples.
What can I do?
by unknown on Oct 10, 2000 at 8:35pm Add comment
I've found that it's usually caused by bits of paper stuck in either side of the assy. 4 screws, and it's easily taken out. Also...the silver metal bar that's part of the assy should be checked to be sure it's clear of glue from labels, paper dust, ect. Clean the rubber rollers with glass plus or windex as well.
by unknown on Oct 10, 2000 at 8:45pm Add comment
Okay, by the four screws I'm assuming that the first two are the ones that are holding in the plate that covers the transfer roller, and the other two are the ones that are directly under the pivoting plate, is that right? Now, should the plate come off as a part of this procedure? Those little springs that connect to the steel bar have me a little concerned, and I'm a bit afraid to mess with that before I know precisely what I need to do.

No small bits of paper or the like are evident, but I suppose it couldn't hurt to tear it down and make absolutely sure.

Thanks for the responses, I appreciate it, and if you have any more insight, that'd be appreciated as well.


by unknown on Oct 10, 2000 at 9:10pm Add comment
The front two screws will not only allow you to remove the plate that partially covers the transfer roller, but also frees the front of the assy. The last two screws are under the 'pivoting plate'. Removing all 4 screws have nothing to do with messing with the springs. Pull the whole assy. up and out. Check for bits of paper, clean the rollers, clean the bar, check underneath where the assy was.
by unknown on Oct 10, 2000 at 9:27pm Add comment
Well, that did the trick -- kind of. I pulled out the assembly, blew it off with some compressed air, and turned the gear a few revolutions. I can now get it to print test pages just fine, but I get hung up at the registration assembly when I try to use the duplexer.

I'll pull it back out tomorrow and clean the rubber rollers just to make sure that they're not the culprit. Anything else I should look out for?

Thanks a bunch!

by unknown on Oct 10, 2000 at 10:04pm Add comment
Actually, if I remember right, if you do a self test, it WILL use the duplexor. Do you use the duplexor normally? Where I work, the duplexor is considered an option and we didnt repair it. Unless it was something extremely obvious or easy to fix, we recommended buying another one. The duplexor has a roller underneath the bottom try that you can pop out and clean as well.
Or pull the whole duplexor out and clean the various rollers. I think it's a few screws in the back, 4 screws on the duplexor itself, then it pulls right out. I bet it's a haven for dust-bunnies.
by unknown on Oct 11, 2000 at 2:07pm Add comment
The duplexer unit itself seems to work just fine, the paper is getting jammed in the registration assy, not the duplexer. I have a feeling that the problems that I was having with the registration assy are still not solved completely.

I'll take a look at the duplexer unit itself and see what I can find, though, just in case that is the problem. Thanks for the advice.

by unknown on Oct 11, 2000 at 2:13pm Add comment
Well, I removed the registration assembly and cleaned it, but I'm still having difficulty with pages getting stuck immediately "in front" of the assembly after they've gone through the duplexer. It doesn't happen on every page, but I'd say 9 out of 10 pages jam in front of the assembly. This only happens with the duplexer.

Anyone have any suggestions ideas or suggestions on other things that I can try?

by unknown on Oct 12, 2000 at 12:51pm Add comment
Hey guys, here at work we use 2 HP's. 1 IIIsi and 1 4si. Both have had the exact same issue and DO NOT have duplexers. The paper just "folds over" itself and hangs up infront of the registration assembly. I dont know if perhaps the registration assemble doesnt turn on until the paper feeding up from the paper pickup rollers goes past a sensor or something, because like what was said eariler, it just stops right before going into the rollers of the registration gizmo. For the love of Pete, please help me.

by Disgruntldtoad on Apr 27, 2006 at 8:16pm Add comment
I've seen registration assemblies where the black plastic cover was rippled cause problems with jamming. The plastic needs to be smooth on the metal backing.
by moe on Apr 27, 2006 at 9:02pm Add comment