Let's see if I understood correctly, you put an original toner with little toner and the printer prints well, without background? If so, your problem is in the cartridge you recharged (OPC PCR) or in the toner with which you recharged, change the option and clean and dry the pcr well and test first, but you will have to try another toner, preferably the specific one For that model. I await comment, best regards
http://uninetimaging.com/c/520/hp-4700-4730?pagenumber=2
In this link you will find the specific toners for your 4700, a detail, the option preferably has to be from the same supplier or origin, because sometimes there are incompatibilities and as a result you get anchored or very clear pages, here a detailed instruction of the remanufacturing process:
http://www.uninetimaging.com/downloads/technical/TecArtWebAdded/HP_4700_4730_MFP_Reman_SPAN.pdf
Check with your supplier of supplies if you have to place the doctor with a separator that runs the contact edge with the developer roller
Some providers recommend those doctor settings for some models, I await your comment, luck, best regards