Konica Minolta 2300dl laser printer complications

Hi,
I have a Konica Minolta 2300dl laser printer which is giving me a lot of problems. It is a colored printer, but it no longer prints in color. I have replaced the old cartridges with new ones, but still it doesn’t print in color. It prints pictures either in black or in light blue. In every paper i print, there is always some odd stains and misprints.
When a paragraph is to be printed, it will print characters twice on the same piece of paper. One line of text appears normally and there is another one, faded, that superimposes on the normal printed lines.
I keep on getting paper rejection error, the papers sometimes does not completely eject from the printer. It leaves about one inch or more inside of the printer, giving the message that there is a paper jam in the printer top.
I recently disassembled the printer and did some thorough cleaning on the components , the rollers and the sensors. I have also tried different types of papers and found out that the ejection problem was solved, but the printing starts 2 inches down the paper top. I still keep on getting mismatch paper errors.
I need help. I am running on Windows 7 Ultimate.
Thanks.
