My lexmark x1270 will not print in black

I have the same problem with my Lexmark X6150. At first I thought the cartridges had dried out due to lack of use (I had not used the printer for some months). Two replacement cartridges arrived but the black cartridge was in poor condition so when the colour cartridge printed but the black didn't I received an exchange.
However, although the paper goes through as though it is printing, the latest black cartridge, like the old, doesn't print, yet the colour is still ok.

I have the same problem with my Lexmark X6150. At first I thought the cartridges had dried out due to lack of use (I had not used the printer for some months). Two replacement cartridges arrived but the black cartridge was in poor condition so when the colour cartridge printed but the black didn't I received an exchange.
However, although the paper goes through as though it is printing, the latest black cartridge, like the old, doesn't print, yet the colour is still ok.

Same thing here, I'm not running Vista.

Same thing here, I'm not running Vista.