Kyocera c5016 Printer-Poor print quality

I have this printer that is driving me mad and no closer to solving the problme. I’ve already tried replacing the repair kit a and updated the firmware yet still the same.

The problem is as follows:

(1)when printing a self test,the black text looks fine,but printing from a pc,the text looks bold/sharp.

(2)when printing in solid color,its fine,but printing in lighter color,its not so fine,you can see the white paper background.

(3)any text/color/shape etc that requires yellow,it has an ghost effect ie you can see bit of the yellow at the top and right hand edge.

I have no ideal what else to do, please help.

Thanks