Heating Member Temperature Control for Fixing Apparatus
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Solution Overview
Problem
In image forming apparatuses, delayed power supply to the heat source when the temperature is high can lead to overshoot, where the heating member's temperature exceeds the fixing temperature excessively.
Innovation Solution
Implementing a control device that switches between a normal mode and a preheating mode based on the temperature state, using a smaller temperature gradient in the preheating mode when the temperature is already high to prevent overshoot, and transitioning to the normal mode once stabilized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the timing to supply electric power to the heat source is delayed when the temperature is high, then the risk of immediate overshoot is reduced, but a large amount of electric power must be supplied which causes overshoot anyway
Solution Approach 1:
The patent applies dynamics by making the heating control adaptive rather than static. The control device dynamically adjusts the heating strategy based on real-time temperature conditions, switching between two distinct control modes (first control when temperature is below threshold, second control when temperature is at or above threshold) to optimize both temperature control and energy efficiency
Solution Approach 2:
The patent changes the control parameters based on temperature state. When the temperature is below the threshold, the system uses one set of control parameters (supply power to reach target temperature), and when the temperature reaches the threshold, it switches to different control parameters (suppress heating to maintain temperature), thereby resolving the contradiction between energy supply and temperature control
2Temperature
If the timing to supply electric power to the heat source is delayed, then overshoot may be avoided, but the temperature rises too slowly affecting productivity
Solution Approach 1:
The system dynamically adapts the heating rate based on temperature conditions. When temperature is below the threshold, aggressive heating is applied for fast response. When temperature reaches the threshold, heating is suppressed to maintain stability. This dynamic adaptation resolves the contradiction between heating speed and temperature stability
Solution Approach 2:
The control device performs preliminary action by predicting the temperature trend and adjusting power supply timing accordingly. When the temperature is approaching the threshold, the system preemptively reduces power supply to prevent overshoot, while when temperature is low, it aggressively supplies power to reach the target quickly, thus balancing speed and stability
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 approach effectively suppresses temperature overshoot by gradually adjusting the heating member's temperature, ensuring it reaches the fixing temperature without excessive elevation.
Implementation Method 1
a heating member 110 and a heat source 120 configured to heat the heating member 110
Implementation Method 2
a temperature sensor 400C configured to detect the temperature of the heating member 110
Data Source
AI summary
An image forming apparatus includes: a fixing device having a heating member, a heat source, a rotating member, and a temperature sensor; and a control device configured to control the heat source, wherein, in a case of a low temperature state where the temperature of the heating member is lower than a predetermined temperature, the control device to control the heat source such that the temperature of the heating member rises with a gradient equal to or greater than a predetermined value, and wherein, in a case of a high temperature state where the temperature of the heating member at the print-instruction receiving time is equal to or higher than the predetermined temperature, the control device to control the heat source such that the temperature of the heating member rises with a gradient smaller than that in the normal mode.