HP 8550mfp Service Manual - Page 128

2 To replace the imaging drum and air filters 1 Open the front door. 2 Swing the upper (blue) lever to the right. Then, press the white button on the lower (green) lever and swing it to the right. 3 3 Pull the drum partway out. Grasp the blue handle on the top of the drum and remove the imaging drum. CAUTION A gray cover protects the new imaging drum. Do not remove this cover; it will come off during the next step. 4 4 Line up the guides and push firmly to slide the new drum into the printer. The cover will slide off as the drum enters the printer. 5 Swing the upper (blue) lever to the left. Then swing the lower (green) lever to the left, making sure it clicks into place. 5 6 Close the front door and open the upper door on the right side of the printer. 7 On the inside of the door, locate the density sensor and the density sensor brush. Use the brush to brush toner particles from the 7 density sensor. Then replace the brush, and close the upper right door. 126 Chapter 4 - Printer maintenance EN