Mich. Comp. Laws § 168.585
Any voting machine which is by law authorized to be used at a general election may, by the order of the board of supervisors of any county, the legislative body of any city, the township board of any township, or the village council of any village, be purchased and used therein at primary elections in like manner and to the same extent that such machines may be used at general elections, and in case there are more candidates than can have their names placed on any such machines so to be used, or in case such machine is so constructed that an elector cannot vote for candidates of more than 1 political party, then it shall be the duty of the proper election commission to designate what names shall be voted for on the machines, and to print the remaining names upon proper ballots in such manner as nearly as may be that the political party or parties polling the largest vote in such county for secretary of state at the last preceding election shall be placed upon the machine, and the candidates of smaller parties shall be placed upon ballots, but all the candidates of any party shall either be upon the machine or upon a ballot.
MCL 168.585