Also when it prints or copies the text is does not show up at all or only partially.

SOURCE: HP LaserJet 2840 Printer

For Flexer and Guest - The Imaging Drum Assy is the 5-th consumable for your printer. U can buy it as well as any toner cartridge. U can find it in the front of the 4 toner carousel with a green plastic cover. Push it to the back of the printer and pull it out straight up. The new one has orange stripes and plastics that you should remove. The Imaging Drum's life is about 20k pages (black with 5% coverage) and 5k page (colour 15% coverage)

SOURCE: HP 2840 All in one won't print color

printer is ok, check the connecting cable and drivers.

SOURCE: not printing on left side of page

The problem is that the revolving drum doesn't contact the OPC drum proberly. You have to open the left side off the machine and replace the little white gear on the shaft that drive revolving drum. The gear has "jumped"one step and the revolving drum isn't parallell to the OPC drum. I fixed my 2840 last night it takes some time but now it works perfect.

SOURCE: HP Color LaserJet 2840 keeps showing 50.2 Fuser

The fuser is the heating unit near the paper exit, and that error means the lamp is burned out, the overtemp sensor is out, or the thermistor in the fuser is bad. About all you can do is replace the fuser. www.precisionroller.com will have a new fuser for you.

SOURCE: hp color laserjet 1600 copies have a blurred image

This sounds like a registration problem.

Use the menu (on the printer) to print antest page AND a configuration/information page.

Look (critically) at the alignment of the seperate coloure Yellow Magenta Cyan. You will probably find that these are out of aligmnent across the page.

The cause of this, is that the printer can't perform a calibration properly (printer probably takes a long time when calibrating too) and is usually down to failure of one of the sensors on the transfer belt.

Sometimes you can clean these and solve the problem, but often is a failure of the component itself. Thes are NOT available as a spare part, and the repair to correct this would need a replacement transfer belt.

Transfer belt replacement in this printer is quite an involved task, though it is within the capabilities of someone with reasonable mechanical aptitude.