Electromagnetic Clutch Sheet Gap Control for Overheating Prevention

The patent implements periodic action by controlling the electromagnetic clutch to operate intermittently rather than continuously. The controller is configured to supply power to the electromagnetic clutch only during specific periods when sheet conveying is required, and stop power supply during other periods. This periodic on-off operation allows the electromagnetic clutch to cool down between cycles, preventing overheating while maintaining the ability to convey long sheets consecutively.

The patent applies preliminary action by predicting when the electromagnetic clutch will be needed and preparing the system in advance. The controller monitors sheet length and conveyor status to determine optimal timing for clutch activation, ensuring power is supplied just before and during required conveying operations. This allows the system to maintain productivity while minimizing unnecessary actuation time and heat generation.

The patent implements dynamics by making the sheet gap a variable parameter rather than a fixed value. The controller dynamically adjusts the sheet gap based on sheet length and conveying conditions. For long sheets, the system maintains larger gaps to reduce clutch actuation time, while for shorter sheets, smaller gaps can be used to maximize productivity. This dynamic adjustment optimizes the balance between printing speed and thermal management.

The patent applies parameter changes by modifying the sheet gap parameter according to specific conditions. The controller changes the sheet gap size based on sheet length measurements and conveying requirements. This parameter adaptation allows the system to maintain high productivity for short sheets while preventing overheating for long sheets by increasing the gap, thereby reducing the duration of electromagnetic clutch actuation.