Unfortunately, all printers do some type of cleaning or purging process
each time they are turned on, or after a certain printing period.
Most inkjet printers made today use one purging/cleaning station that
covers all the heads at the same time, so with each cleaning or purging
cycle, all the heads are cleaned and purged at the same time, meaning a
lot of colored inks are used up even if they are not printing.
Therefore, all inks are used even if you aren't printing with them.
There are no perfect solutions to this. If you will only be printing
with black ink, you can consider buying a chip resetter, and filling the
color cartridges with a inexpensive cleaning fluid, which will keep the
color heads unclogged, but won;t cost a lot to keep filled and refilled,
and will protect the color heads from major clogging. However, you
won;t be able to print in color without replacing those cartridges with
real color ones.
Unfortunately, I don;t know of any other method to keep the printer
printing, nor the heads functional.
Art