Epson ink jet

[John]

Why cant the Epson printer if it runs out of a colour ink cart just
print black and white if you select greyscale within advanced settings?

It's absurd that you have to replace a yellow cart just to get a black
and white letter to fire out. I'm sure my old Canon didn't have this
issue if the colour cart ran out the black still kept going.

[Tony]

Post by John
Why cant the Epson printer if it runs out of a colour ink cart just
print black and white if you select greyscale within advanced settings?
It's absurd that you have to replace a yellow cart just to get a black
and white letter to fire out. I'm sure my old Canon didn't have this
issue if the colour cart ran out the black still kept going.

The jets on ink print heads need to be lubricated or cooled depending on the
design so if the ink runs out there is no lubrication or cooling and the heads
will dry out and/or fail.
Epson print heads "squeeze" the ink through the nozzles using a piezo
technique, other printheads use heat to do the same thing.
That is why all ink is used slowly even if you do not print colour, cleaning
cycles are regularly and automatically run to keep the nozzles in good
condition.
So although I sympathise with your position there is a technical reason for the
behaviour.
Printers that have the print head as part of the cartridge (integrated) do not
have this issue so if you had for instance a Canon or HP printer with integral
print heads (one colour and one black cartridge) the other cartridge would
continue to work in most cases.
To further complicate matters, some printers use colour ink even when printing
grayscale.
Tony