CLEAN DENSITY SENSOR or CALIBRATION ERROR

HP CLJ 8500 and 8550 Series Printers Troubleshooting a CLEAN DENSITY SENSOR or CALIBRATION ERROR message

Introduction
The printer displays the message Clean Density Sensor - Cycle Power Calibration Error - Cycle Power OFF then ON ( this message if printer is equipped with 15 May 2001 firmware)

These errors indicate a calibration error has occurred. During calibration, a D-MAX and D-HALF block is placed on the ITD.

D-MAX: Sets color plane density, writes solid-fill density pattern to ITD, then center mounted density sensor measures reflectance.

D-HALF: Measures and sets image half-tone density using density settings from previous D-MAX calibration. A half-tone pattern is written to the ITD, and then the center mounted density sensor measures reflectance.

Printer calibration occurs at the following intervals:

After the power is turned ON
After 50 pages in one-page mode are printed (after initial power-on)
After 95 pages in one-page mode are printed
After the printer is revived from Power Save (if Power Save has been on for more than 30 minutes)
When a print cartridges is installed
When an imaging drum cartridge is installed
When environment is changed by the environment change control

CLEAN DENSITY SENSOR and CALIBRATION ERROR messages are typically symptoms of print quality defects and do not have anything to do with a defective density sensor or the density sensor monitoring system which includes density sensor, cabling, and/or controller. Very few of these errors have ever been resolved by replacing these parts.

Troubleshooting a CLEAN DENSITY SENSOR or CALIBRATION ERROR message

Power the printer ON. Despite the fact that the printer reports a CLEAN DENSITY SENSOR or CALIBRATION ERROR, print a configuration page from the control panel of the printer.

How do the internal test pages look?  Once the print quality issue has been addressed, the CLEAN DENSITY SENSOR or CALIBRATION ERROR message should be resolved.

Print an Event Log and notate any density sensor errors listed. The error messages break down as follows:

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

NOTE: The density sensor spring is not shipped with a replacement density sensor. Ensure the density sensor spring is present and if the density sensor is to be replaced, swapped from the old to the new assembly. The density sensor is also not shipped with a replacement Tray 1 pickup assembly. Ensure the density sensor is present and the Tray 1 pick assembly is being replaced, swap it from the old to the new assembly.

NOTE: If this spring is missing, consult with an SSOE for further assistance as the spring is not an orderable part.
Figure 1: Spring connected to density sensor

1 - Transfer this spring along with the density sensor

© 2005 Hewlett-Packard