Brother MFC copies faint, but prints fine
We have had 2 separate Brother MFC-L6700DW machines that both print nicely, but the copies are light, and when copying blue ink it's often unreadable.
If I manually increase the contrast and density, the copies are fine, but this is a huge hassle to do every time and we shouldn't need to do so. Also, there does not seem to be a way to make increased contrast and density the default settings.
The problem is the same whether copying from the ADF tray or the glass.
In the first machine, we didn't have this problem when we were using a remanufactured toner cartridge. The problem started when we installed a genuine Brother toner cartridge, and it continued when we installed a second genuine Brother ton cartridge.
Brother sent us a replacement machine, and we transferred the same drum and genuine Brother toner cartridge from the first machine to the second, and the problem persisted.
I would go back to using remanufactured toner cartridges, but they caused other, more troublesome issues.