HP LaserJet 4250

[servicemax]

Re: HP LaserJet 4250

I have had so much trouble with replacement sleeves and rebuilt fusers that I only use OEM HP New.

If you remove the fuser and see a pile of gray dust just below the fuser drive gear on the left side, the swing plate assembly probably needs to be replaced.
This problem seems to be most prevalent on the 4250 printers.

Another good indication that this assembly is worn out is a rumble sound when printing.

[prntrfxr]

Re: HP LaserJet 4250

I believe bad fuser bushings create the swing plate issue. If you install a fuser with old bushings an replace the swing plate, you will end up having to replace the swing plate again in the near future. Try TSAWorld. Bushings are changed whether or not they need it, everytime.

[RHBlakeman]

Re: HP LaserJet 4250

Well here's an example of my in-field film/sleeve replacements...I replaced one in a 4100 today, edges worn through the grey layer into the beige. Crap film? Nope it has 325k pages since I rebuilt it (new bushings, gears and pressure roller too) in 2009. 4 yrs and 325k pages is more than I ever got on a rebuild from a vendor or HP. Replaced a 4200 last week that was 250k, 2 yrs old. Both from Partsmart and grease is Uniflor 8172 from Liberty. Only sleeves I don't get from Partsmart are the metal 4250/4350 ones as they never work right - the Japanese ones from Liberty last well over the normal maintenance cycle. I did get a batch of 10 film sleeves for the smaller printers (2100/2200, etc) from DonParts via eBay 2 yrs ago and every single one (except one) is still in service. One failed 2 months after I replaced it due to the user yanking a jam out without letting the release levers down on a 1022n. The one I replaced it with is from the same batch of 10 so I got 9 fusers rebuilt from that batch and shipped it was 16 dollars for 10.

[RHBlakeman]

Re: HP LaserJet 4250

Also one thing to note on the fusers that have a film and grease that have issues with smears or bad stripes down them even after a new sleeve - heating element. Some like the 4200 series have a dual element ceramic strip and if one burns out the working one will get it working but you will notice the first page after it sits will smear and the rest will be fine, but it will seem overly hot. Replace the ceramic heater strip using the proper adhesive (some don't have adhesive, use clips to hold it in) and all will be well for a long time to come. In some instances you may notice a smear in one area down the length of the page on every page. Appears to be a bad toner but won't change when the toner is changed. Heating element. I did a 1022n and even though the single element strip ohm'd out fine it had a defect you could see when you took the heater strip out, same place as the print defect. Changed it and a printer that was tossed in the trash is now my wife's office printer for the cost of a heater strip and new film, less than $20.

The least probable to fail are connectors, IR sensors, thermal cutouts and thermistors. I do have to replace the sensor harness on HP 9000 fusers because the lamps cause the poorly placed wiring to get burned. Partsmart sells the 9000 harness since about 2012 and pretty cheap actually. In the last 5 yrs I've changed 1 thermistor and in the time I've been in business since 1995 I've replaced one thermal cutoff, on an LJ 8100/8150 fuser. I had to change the thermistor with it as the thermistor malfunctioned, the lamps went way too hot and the thermal cutoff opened. The rest of the fuser also showed signs of excessive heat as well, like a broken crumbly upper roller gear, dried ball bearings, etc. That machine, with the same fuser frame, is still in daily use at the local hospital.