To minimize heat displacement, the machine units are designed to produce the minimum amount of heat during operation. Additionally, there is automatic compensation for changes in the room temperature that is based on data obtained during tests performed in a temperature controlled room. As a result, machine heat displacement is less than 10ƒÊm with a room temperature change of 8Ž. The exhaust duct used to remove heated air generated by machine operation is arranged so that it will not affect adjacent machines.