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Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 1:45 am
by ludi
I have an ancient HP LaserJet 4L, a slow and low-resolution printer that has been fantastically reliable. At some point in the distant past I maxed the onboard memory and that solved the only complaints I ever had about it, since I only print mixed text and low-res graphics. It currently runs as an IP printer using a TrendNet print server.

Very recently, it started spitting out a couple thick gray lines on the right-most side of every page, but the actual print content is fine. Is this a sign of a toner cartridge problem, or is the fuser finally dying?

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 2:05 am
by Starfalcon
Yeah, thats the fuser, had several of those do that at my previous job.

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 6:30 am
by Chrispy_
See if you can get a replacement fuser, even though the price might tempt you to get a newer, quieter, faster, higher-dpi laser.

Those LaserJet 4L's are workhorses. We had one in the old firm I worked for. We also had a Laserjet 8150N there that I am proud to say passed it's millionth page with less servicing (in the five years I was there) than any of our leased Xerox machines need in a fortnight. Those Canon print engines are amazingly reliable.

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 1:48 pm
by ludi
Okay, I kind of thought so. Any suggestions for a reputable supplier? Newegg doesn't have them, Amazon is only offering used models from Marketplace sellers, the major office supply stores show nothing in their online catalogs.

I found this although the website is a bit slap-dash:
https://www.sundatasupply.com/product_d ... MgodYCEAOg

EDIT: On second thought, maybe it is the print cartridge. I pulled it out an took a look at the print drum, there are some deep wear grooves along the edge which seem to be picking up excess toner.

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 2:17 pm
by satchmobob
Easy way to troubleshoot this. Just stop the print half way through by opening the toner access panel before the page gets to the fuser or just power off half way through.
If your gray lines are there before it gets fused then probably the drum/toner. Give it a try.

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 3:47 pm
by Ryu Connor
That sounds more like a damaged drum to me.

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 5:39 pm
by SecretSquirrel
Drum. To much toner is always the drum. The drum is electrically charged (positive I believe) and the laser prints a negative charge on the surface. The toner has the same charge as the unexposed drum and so only sticks where the laser exposed it. This is then transfered to the paper by pressure contact. All the fuser does is melt the toner into the paper. It doesn't add or remove toner. If the image is correct on the paper but smears or flakes off, then you have a fuser problem. The problem you describe can be caused by wear on the print drum, a light leak that is exposing the drum, or probably some other things I no longer remember.

Most printers these days include the print drum in the toner cartridge, but some older printers didn't. The drum was a seperate replacable item, mainly because it was really expensive. Don't remeber how the 4L is laid out. I haven't worked on one since the mid 90s.

--SS

Re: Toner cartridge, or fuser?

Posted: Sat Dec 01, 2012 5:55 pm
by ludi
The drum is in the toner cartridge. The existing cartridge is an OfficeDepot reman with at least 3-4k sheets to account for, so no big surprise. I'll pick up another one and see what that does.

Re: Toner cartridge, or fuser?

Posted: Sun Dec 02, 2012 12:38 am
by satchmobob
SecretSquirrel wrote:
Drum. To much toner is always the drum. The drum is electrically charged (positive I believe) and the laser prints a negative charge on the surface. The toner has the same charge as the unexposed drum and so only sticks where the laser exposed it. This is then transfered to the paper by pressure contact. All the fuser does is melt the toner into the paper. It doesn't add or remove toner. If the image is correct on the paper but smears or flakes off, then you have a fuser problem. The problem you describe can be caused by wear on the print drum, a light leak that is exposing the drum, or probably some other things I no longer remember.

Most printers these days include the print drum in the toner cartridge, but some older printers didn't. The drum was a seperate replacable item, mainly because it was really expensive. Don't remember how the 4L is laid out. I haven't worked on one since the mid 90s.

--SS


This isn't quite true. The toner is transfered to the page not by pressure but charged transfer roller which always lives directly opposite the drum in the paper path. The page travels between the transfer roller and the drum and the charge electrically 'pulls' the toner off the drum and onto the page.
Also, too much toner can be caused by many things besides a faulty drum, including a faulty fuser. Toner can be left on a faulty fuser from previous prints and then be transfered to the next print as the page passes through or even onto the same page causing ghosting of the image down the page. A faulty transfer roller or HV PSU can also cause excessive toner.

Finally, there are many, many modern printers that still use a separate drum and toner unit. Loads of Brother printers, Kyocera, samsung and Oki to name a few.

However in this case I'd fully expect it to be the drum/toner cart.

Re: Toner cartridge, or fuser?

Posted: Thu Dec 13, 2012 12:58 am
by ludi
I installed a Xerox-branded toner cartridge tonight, and it prints perfectly now.

The Xerox cartridge was about $35 compared to $12 for the cheapest reman, but for the 5k+ pages I hope to get out of it, that's nothing. I didn't really feel like paying $70 for the OEM unit, and since Xerox does have a reasonably competent office printer line, I'm hoping their print drum will prove to be higher quality than the remans.

Re: Toner cartridge, or fuser?

Posted: Thu Dec 13, 2012 11:38 am
by shaq_mobile
good job keeping an old printer workin! personally, i love the older HP laserjets. we only have about 5 out of 1200 printers that are still LJ4, but we have hundreds of 4000s, 4050s, 4100s, 4200s and 4250s floating around. people complain about them, but thats mostly because their plastic is discolored from age and they assume an ugly printer is a bad printer. most folks dont realize the duty cycle of a lot of those mid range laserjets is well into the tens of thousands a month. Most folks think 50 pages a day is an obscene amount. out of all the printers in our organization, there's only one that approaches it's duty cycle and it prints a 9000 page report once a week. anyways, grats!