With the MFC-L3770CDW, after installing the new toners, the printer shows on the display that no original toners are installed. The toner level and all functions are OK. However, I suspect that brother is reducing the print quality via software. Especially grey areas are only printed weakly (pale) with this product. However, text and lines come out perfectly. This is presumably not a manufacturer problem on the toner side but a manipulative intervention by brother.