Fixing Unit Heater Control for Flicker Reduction
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Solution Overview
Problem
Existing image forming apparatuses experience current imbalances and increased flickers due to rapid switching of the fixing heater, particularly in low temperature environments, leading to inefficient energy usage and device instability.
Innovation Solution
A fixing unit with a switching unit and control unit that employs specific energization patterns, consisting of odd numbers of half wave periods in a control cycle, ensuring non-successive arrangement of ON and OFF periods to minimize current imbalances and flickers, and utilizing multiple heaters with separate switching units and staggered energization patterns when turned on simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fixing heater is turned on rapidly to inhibit temperature ripples, then temperature control precision is improved, but flicker influence becomes more conspicuous
Solution Approach 1:
The patent applies periodic action by controlling the switching unit to operate in synchronization with the AC power source's half-wave periods. The control unit switches the fixing heater on and off at specific half-wave periods, creating a periodic energization pattern that maintains temperature control while reducing flicker effects. This is achieved by selecting energization patterns where the number of ON periods and OFF periods are arranged to avoid successive small-number periods, thereby periodically distributing the thermal energy input.
2Stability of the object's composition
If the switching unit frequently switches on/off the fixing heater to maintain temperature, then temperature stability is improved, but current imbalance increases
Solution Approach 1:
The control unit implements periodic switching synchronized with AC half-wave periods, creating structured energization patterns that maintain temperature stability while managing current flow. By organizing ON and OFF periods in specific sequences (avoiding successive small-number periods), the system achieves temperature control without excessive current imbalance.
Solution Approach 2:
The patent changes the parameter of switching timing from arbitrary or simple on-demand switching to switching based on AC half-wave period synchronization. This parameter change allows the system to optimize both temperature stability and current balance by aligning switching events with the natural cycle of the power source, thereby reducing harmful current imbalances.
3Device complexity
If the fixing heater is controlled with simple on/off switching, then device complexity is reduced, but flicker and current imbalance worsen
Solution Approach 1:
The control unit employs feedback by monitoring temperature conditions and selecting appropriate energization patterns from multiple predefined options. Based on the detected temperature state, the control unit chooses switching patterns that optimize performance while minimizing flicker and current imbalance. This feedback mechanism allows the system to maintain relatively simple hardware while achieving sophisticated control through software-based pattern selection.
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
The solution effectively reduces flickers and current imbalances, enhancing energy efficiency and device stability by optimizing the switching patterns and heater control, thereby improving the overall performance of the image forming apparatus.
Implementation Method 1
a fixing heater (53) to be turned on by energization and perform thermal fixing
Data Source
AI summary
An image forming apparatus is provided with a fixing unit in which flickers can be effectively reduced while inhibiting electric current imbalance. The fixing unit comprises a fixing heater, a switching unit for switching the fixing heater on/off with an AC power source, and a control unit which controls the switching unit to switch in units of the half wave period of the AC power source AC, and a storing unit for storing a plurality of energization patterns which define the ways of performing the switch control. Each energization pattern corresponds to a control cycle which contains a three or more odd number of the half wave periods each of which is either an OFF period and an ON period, and all the half wave periods of the smaller in number of the ON periods and the OFF periods are not successively arranged.