If there isn’t a minyan on Shabbos I heard the kehillah should read the parashah from a chumash. Should it specifically be a chumash or could it be from something printed out?
If most of the tzibbur didn’t hear the reading, it should be read from the sefer torah and added to the reading of the next week, (but we don’t read more than two parshios in one week). I am not aware of a halacha that an individual has to read the parsha from a chumah., aside from being maavir sedra.
O:CH 135-2, M:B 135-6