Heated System Temperature Control via Seeding Value
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Solution Overview
Problem
Heated systems in printers, such as dryers and fusers, often experience thermal overshoot during the ramp-up period, leading to damage, media jams, and poor page-to-page alignment due to the rapid increase in temperature, which existing control methods fail to prevent effectively.
Innovation Solution
A controller is implemented to manage the power supply to the heat generating device, stopping power delivery before the target temperature is reached during the ramp-up period and using a calculated seeding value for feedback control during the steady-state operation to maintain the temperature within a predefined accuracy, thereby preventing thermal overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If maximum power is supplied to the heat generating device during ramp-up, then the temperature increases quickly to the target temperature, but thermal overshoot occurs causing damage, media jams, and poor alignment
Solution Approach 1:
The system performs preliminary heating at maximum power until a threshold temperature is reached, then pre-calculates the remaining power and time required to reach the target temperature. This preliminary action allows the system to prepare for the transition to feedback control, preventing thermal overshoot while maintaining fast ramp-up performance.
Solution Approach 2:
The system implements feedback control by continuously monitoring the temperature and using the pre-calculated remaining power and time to determine the appropriate power level. This feedback mechanism ensures the temperature reaches the target accurately without overshooting, resolving the contradiction between fast heating and reliability.
2Device complexity
If existing control methods are used during ramp-up, then the system structure remains simple, but thermal overshoot cannot be prevented effectively
Solution Approach 1:
The system performs preliminary calculations of remaining power and time required to reach the target temperature before initiating feedback control. This preliminary computational action enables sophisticated temperature control without requiring complex hardware, maintaining simplicity while improving reliability.
Solution Approach 2:
The system changes the control parameter from simple on/off control to calculated power modulation based on remaining power and time. This parameter change allows precise temperature control during ramp-up without adding significant system complexity, preventing thermal overshoot effectively.
3Reliability
If power is stopped before the target temperature is reached, then thermal overshoot is prevented, but the temperature may not reach the setpoint during ramp-up
Solution Approach 1:
The system uses feedback control after the preliminary heating phase to continuously adjust the power level based on the temperature sensor readings. This feedback ensures the temperature reaches and maintains the exact setpoint, resolving the contradiction between preventing overshoot and achieving accurate temperature control.
Solution Approach 2:
The preliminary calculation of remaining power and time provides an accurate prediction of how much heating is needed to reach the target. This preliminary information, combined with feedback control, ensures the temperature reaches the setpoint precisely without overshooting, maintaining both reliability and manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents thermal overshoot, reducing the risk of damage and improving print quality by maintaining the temperature at or near the setpoint, thus enhancing the reliability and consistency of the printing process.
Implementation Method 1
a heat generating device that, when a media is to be conditioned, may be supplied with a maximum amount of available power to quickly ramp up the temperature in the heated system to a target temperature
Implementation Method 2
a temperature sensor that may detect the temperature in the heated system
Implementation Method 3
a control mechanism that may control the delivery of power to the heat generating device to cause the heat generating device to maintain the temperature in the heated system at or near the setpoint temperature following the ramp up period
Data Source
AI summary
According to examples, a heated system may include a heat generating device, a temperature sensor to detect temperature in the heated system, and a controller. The controller may store temperatures detected by the temperature sensor over time and based on a determination that the temperature in the heated system has reached a predefined temperature value, stop application of power to the heat generating device. The controller may also calculate a rate of change of the stored temperatures corresponding to a predefined period of time prior to the application of power to the heat generating device being stopped, may determine a seeding value for a control mechanism of the heat generating device based on the calculated rate of change, and based on aa determination that a predefined condition has occurred, control the control mechanism to apply power to the heat generating device beginning with the determined seeding value.