hp l jet 8550 density sensor ,i forgot

[grahamant]

can anyone remind me . there is something about this senor when it says its failed i fitted new one but cannot help thinking there is somthing else about it OR have i finally gone senile? thanks graham (i think)

 

[hpwizzard]

You get "Clean density sensor error" in the display on power up ?

Even though the printer reads "Clean density sensor" you should be able to print internal pages.

How does the configuration page look ? Does the colors appear OK ?

Check the event log for any of these :
54.00.06 is out of range cyan
54.00.07 is out of range magenta
54.00.08 is out of range yellow
54.00.09 is out of range black

Please ensure that the density sensor spring is present. If you replaced the sensor the spring does not follow that kit.

You might also wanna check for cracked ITD guide :
A cracked ITD guide allows the back (right if facing the right access door), of the transfer drum to sag. The transfer drum is no longer parallel to the cleaning roller. As a result, the cleaning roller cannot clean off the first color plane before the next color plane is developed and transferred onto the transfer drum. This later color plane is transfer over the residual toner already on the transfer drum. The later color planes appear to be corrupted. This issue laying down the calibration blocks results in the “Clean Density Sensor” message.

Also, if the ITD guide is cracked it does not properly hold the back of the transfer drum in contact with the imaging drum, this results in the color planes not being able to completely transfer to the transfer drum. Again, the density sensing system gets confused and posts the “Clean Density Sensor” message.