Duty cycle.

Duty cycle is a maximum rating for how hard a device may be worked, quoted in the printer trade as a rated throughput of pages per month and borrowed from the engineering term for the fraction of a period a system is active. It is a ceiling the machine is tested to survive, not a volume it will hold month after month, and that is the line shops cross. Where a vendor publishes a recommended monthly volume as well, treat that as the planning number and the duty cycle as the limit; where only a duty cycle is published, assume your sustainable volume sits somewhere below it. Size a press off the ceiling figure and you carry the difference yourself, as a head or a fuser gone mid-shift on the run you promised for Friday.