asked Sep 10, 2007 at 1:46pm
Hp HP LaserJet 2420DN


We have a 2420dn at work. Recently the toner cartridge went empty. Perfectly normal process, print just kept getting lighter. Put in a new cartridge, and suddenly it won't print. no error message; pages just come out blank. We assumed it was a bad cartridge and tried at least one more, same result. Did we have some serious failure at just the same time as the cartridge went empty, do you reckon, or have we just tried several bogus replacement cartridges. (First was a reman we were sent by mistake, second was a new HP cartridge.) No matter which way you look at it, it seems like a big concidence.
Having once gone out on site for a similar problem (different model) and been told they tried 3 new cartridges, I have to ask. Did you pull the seals? All 3 that I looked at that day had the seals still installed.
by moe on Sep 10, 2007 at 1:52pm Add comment
You need to check the laser scanner assembly and make sure nothing is blocking the laser.
by msr976 on Sep 10, 2007 at 1:53pm Add comment
check the three toner contact springs at the left hand side, you will probably find them damaged. they are small upright springs with a black plastic cap on the end.
by laserphil on Sep 11, 2007 at 12:24am Add comment
I can say with certainty that the seal was pulled on the last cartridge, because I took it out to check exactly that. (I didn't install any of them right out of the box.) How do I check for a blocked laser?
by dimdem on Sep 11, 2007 at 3:06am Add comment
Cartridges worked in another printer. Contact springs seem okay as far as I can tell---not obviously bent and they seem to move easily.
by dimdem on Sep 11, 2007 at 8:30am Add comment
Feed a page in from the manual feed and when the end disappears into the printer, open the lid and take out the cartridge. Pull back the drum shutter and see if there is any kind of image on the drum.
by moe on Sep 11, 2007 at 12:10pm Add comment
No, no image on the drum.
by dimdem on Sep 12, 2007 at 8:55am Add comment
If you look at the top right of the toner cartridge, you should see a "shark fin" sticking up. That fin pushes on the laser shutter to open it. If either the fin was broken or the mechanism that opens the shutter, then the laser couldn't shine on the photoconductive drum in the toner cartridge. Check that and push on the piece of plastic in the slot and see if there is some resistance on it. If that is OK, then we'll blame a lack of high voltage. That would either be the contacts to the toner cartridge or possibly a bad controller board. 90\% of the time it's contact problems.
by moe on Sep 12, 2007 at 10:16am Add comment
Shark fins is there, and the piece of plastic it pushes on seems okay. Moves when pushed but isn't just loose. I tried cleaning the contacts with a pencil eraser, but I can't test the outcome until some network problems get resolved. Thanks.
by dimdem on Sep 12, 2007 at 11:30am Add comment