fuser heater delay on first printed pages in hp laserjet 2055dn

[parsmehregan]

Hi
As usual for worn and faulty fuser film in hp 2035 & 2055dn, film and press roller has been replaced. but when initializing the printer, as it is obvious in the attached picture, the demo page has vertical damaged print just in the middle of the printed paper. after 4 or 5 pages it prints fine with no sign of toner trail.
I opened the fusing unit again to check the problem,some toner has been stuck to center part fuser film.
If the problem is the quality of fuser film, why just center part has damaged print. It should be something about the fuser heater delay, when first print starts it could not warm up properly and after few pages it gets fine,or something related to heat sensor!
Does anyone had same experience and whats your suggestion for this issue.

Thanks

[Attila]

Re: fuser heater delay on first printed pages in hp laserjet 2055dn

Chinese film an roller are made by different material. Increase fuser temperature. Easiest way is to select transparency or heavy paper.

[parsmehregan]

Re: fuser heater delay on first printed pages in hp laserjet 2055dn

Could it be due to thermistor failure?
any other idea ?

[Attila]

Re: fuser heater delay on first printed pages in hp laserjet 2055dn

Could it be due to thermistor failure?
any other idea ?

100% is not a thermistor fault.
Chinese rollers and films are not the same quality: Film is a little bit thicker, you can measure it by a micrometer, and less heat conducting. Rollers are softer and not so much heat blocking.

Becouse roller is softer, not enough pressure on the paper. Not enough pressure means not enough heat transfer to the paper. It has to pass some time to heat the EXTERNAL part of the film and the paper, as much as the internal part, where the thermistor is. The thermistor is sensing the good temperature, but the surface temperature and heat transfer is not enough.

Try to increase the pressure on the paper in some way. Or you can increase the fuser temperature by some service software if you got one. Maybe some additional resistor to alter the sensed temperature of the termistor, if you are good in electronics.

No other solution.

[parsmehregan]

Re: fuser heater delay on first printed pages in hp laserjet 2055dn

100% is not a thermistor fault.
Chinese rollers and films are not the same quality: Film is a little bit thicker, you can measure it by a micrometer, and less heat conducting. Rollers are softer and not so much heat blocking.

Becouse roller is softer, not enough pressure on the paper. Not enough pressure means not enough heat transfer to the paper. It has to pass some time to heat the EXTERNAL part of the film and the paper, as much as the internal part, where the thermistor is. The thermistor is sensing the good temperature, but the surface temperature and heat transfer is not enough.

Try to increase the pressure on the paper in some way. Or you can increase the fuser temperature by some service software if you got one. Maybe some additional resistor to alter the sensed temperature of the termistor, if you are good in electronics.

No other solution.

In order to increase the fuser temperature, i cut a piece of old film and put it under heating lamp, where the sensor located, but the heat went up and some melted toner appeared on the printed paper , so i took it out.
I still can't figure it out why damaged print appears like a vertical column in the middle of page , not right or left part ?
I'm going to change film,then heating lamp and whole fusing unit with another one to find out the faulty part!

Thanks anyway

[Attila]

Re: fuser heater delay on first printed pages in hp laserjet 2055dn

I suppose the roller is softer in the midle. So not the same pressure, lesser pressure, less heat contact.