Hello,
I just acquired a Konica 7033 copier, with around 215K copies on it. The print quality was quite bad and streaking originally, so I installed the Konica PM kit, which primarily consisted of new corona wires, charging grid, some transfer rollers, and a new drum cleaning blade. After doing this, the quality improved substantially and the streaking disappeared.
Now I am left with a gray or "dirty" background on the page. Text, etc. is clearly reproduced, but the page is dark, similar to what you see if the darkness control is adjusted way down, or on some printers when the toner cartridge is near empty. I've performed all the Konica recommend adjustments in the service manual, with no change to the print quality. Copying a blank sheet of paper still yields a blank sheet with a new gray background.
The service manual does not address this problem. I suspect the drum may need to be replaced, but from researching this type of problem on the internet, other people have suggested developer or other issues. I'd appreciate any tips or guidance anyone can offer on how to narrow down the cause of the problem without replacing things wantonly.
Thanks, Dale