NTC Fuser Heat Generating Body for Multi-Voltage Image Forming Apparatus
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Solution Overview
Problem
Image forming apparatuses with multiple rated voltages face challenges such as increased manufacturing costs, size, and weight when using multiple heat generating bodies, and inrush current and flicker issues when using a single halogen lamp with a positive temperature coefficient (PTC) characteristic under varying voltages.
Innovation Solution
An image forming apparatus with a voltage detecting unit, control unit, and fusion driving circuit that controls AC power waveforms and phase to maintain a target temperature using a heat generating body with a negative temperature coefficient (NTC) characteristic, such as a carbon or carbon nanotube heat generating body, to suppress inrush current and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fuser includes a plurality of heat generating bodies having resistance values respectively corresponding to rated voltages, then the fuser can operate at multiple rated voltages, but manufacturing costs, size, and weight increase
Solution Approach 1:
The patent employs a single heat generating body that can operate across multiple voltage ratings (e.g., 100V, 120V, 220V, 240V) by controlling the RMS voltage applied to it. This universal approach eliminates the need for multiple separate heat generating bodies, thereby reducing fuser weight while maintaining multi-voltage operation capability.
2Adaptability or versatility
If a fuser includes a single heat generating body with PTC characteristic, then manufacturing costs and weight are reduced, but inrush current and flicker occur during high voltage operation
Solution Approach 1:
The patent changes the voltage parameter applied to the heat generating body by controlling the RMS voltage to different levels corresponding to various rated voltages (100V, 120V, 220V, 240V). This parameter control prevents excessive voltage application that would cause inrush current and flicker, while still enabling the single heat generating body to operate across multiple voltage ratings.
3Power
If a halogen lamp with PTC characteristic is driven at high voltage, then desired power level is achieved, but inrush current occurs due to low resistance at low temperature
Solution Approach 1:
The patent implements preliminary control of the voltage applied to the heat generating body before full power operation. By controlling the RMS voltage to appropriate levels based on the rated voltage detection, the system prevents the low-resistance state from causing inrush current while still achieving the desired power level for fusing operation.
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 allows for efficient fusing temperature control across multiple rated voltages, reducing manufacturing costs and weight by using a single heat generating body while effectively suppressing inrush current and flicker, maintaining stable fusing performance.
Implementation Method 1
a heat generating body having a negative temperature coefficient (NTC) characteristic, which receives the fusing power and generates resistance heat
Implementation Method 2
a heat generating body having a negative temperature coefficient (NTC) characteristic, which receives the fusing power and generates resistance heat
Data Source
AI summary
An image forming apparatus having two or more different rated voltages, the image forming apparatus including a voltage detecting unit, which detects a voltage level of alternating current (AC) power supplied from outside of the image forming apparatus; a control unit, which outputs a control signal according to the detected voltage level; a fusion driving circuit, which controls a number of waveforms and phase of the AC power according to the control signal and outputs the controlled AC power as fusing power; and a fuser including a heat generating body having a negative temperature coefficient (NTC) characteristic, which receives the fusing power and generates resistance heat; and a heating member, which is heated by the heat generated by the resistance heat generating body and fuses an image formed on a printing medium.