Fixing Device Temperature Control via Dual Difference Feedback
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Solution Overview
Problem
Conventional fixing devices face challenges in effectively suppressing temperature ripples, leading to issues such as excessive toner melting, image defects, and increased power consumption, particularly due to low heat capacity and rapid temperature changes in the fixing members.
Innovation Solution
A fixing device with a temperature control system that calculates a first temperature difference between the current and target temperatures and a second temperature difference based on past readings, using these differences to determine the power supply through a stored table, ensuring appropriate heat delivery and reducing temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heat capacity of the fixing member is lowered to reduce warming-up time, then productivity is improved, but temperature control becomes difficult and temperature ripples increase
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to control the heating member in a cyclic manner. The control unit switches the heating member on and off periodically based on the temperature difference between the fixing member and target temperature, creating a rhythmic heating pattern that prevents temperature ripples while maintaining fast warming-up performance.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the temperature of the fixing member via the temperature detection unit and adjusting the heating control accordingly. The control unit receives temperature information, calculates temperature differences, and modulates the heating member's operation based on this feedback, creating a closed-loop system that stabilizes temperature despite low heat capacity.
2Productivity
If the output of heating means is increased to heat the fixing member faster, then productivity is improved, but temperature ripples widen and image quality deteriorates
Solution Approach 1:
The patent uses periodic action through PWM control to deliver heating energy in controlled pulses rather than continuous high-power output. This rhythmic heating pattern allows rapid temperature rise while preventing excessive temperature spikes that would cause ripples and image quality deterioration.
Solution Approach 2:
The patent applies dynamics by making the heating output variable rather than fixed. The control unit dynamically adjusts the heating member's output based on real-time temperature feedback, transitioning between different power levels to maintain optimal heating speed while preventing temperature ripples and ensuring image quality.
3Device complexity
If conventional temperature control methods are used, then device complexity is low, but temperature ripples are not suppressed and power consumption increases
Solution Approach 1:
The patent replaces conventional mechanical or simple on/off temperature control with an electronic control system that uses PWM and feedback mechanisms. This substitution enables precise temperature regulation and ripple suppression while maintaining relatively simple device architecture through integrated control circuits and sensors.
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 ripples, preventing image defects and reducing power consumption by ensuring consistent heat delivery, thus maintaining image quality and optimizing energy use.
Implementation Method 1
a heating member (32) that heats the fixing belt (33)
Implementation Method 2
the unfixed toner image is fixed by heat and pressure
Data Source
AI summary
First, a first temperature difference and a second temperature difference are calculated. The first temperature difference is a difference between (a) a first detected temperature that is a current temperature of the fixing member and (b) a difference of a control target temperature for the fixing member. The second temperature difference is a difference between (a) the first detected temperature and (b) a past temperature of the fixing member which past temperature was detected a predetermined time earlier than the current time. Then, by reading out, from a table prepared in advance, an amount of power to be supplied to a heating member which amount corresponds to a combination of the first temperature difference and the second temperature difference, the amount of power to be supplied to the heating member is determined. In accordance with this amount of power determined, an actual amount of power supplied to the heating member is controlled. This makes it possible to simply and effectively suppress a temperature ripple of the fixing member.