Heating Element Duty Control for Print Speed and Current Limits
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in minimizing print speed drops while preventing current limitations, especially when controlling the heating temperatures of image and non-image portions, as they often require equally setting current limits for all heating elements, leading to unnecessary current limitations.
Innovation Solution
The apparatus includes temperature and current detecting portions to individually control the energizing duty of heating elements, setting different control target temperatures for image and non-image regions, and dynamically adjusting the energizing duty based on detected temperatures and current levels to stay within the commercial power supply's limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If current is limited equally for all heating elements to prevent exceeding commercial power supply capacity, then current consumption is controlled within limits, but print speed drops more than necessary due to excessive current limitation
Solution Approach 1:
The heating elements are divided into multiple groups corresponding to different heating regions (image portions and non-image portions). Each group can have its energizing duty independently controlled, allowing differential current management. This segmentation enables the system to supply more current to heating elements processing image portions while limiting current to those processing non-image portions, thus preventing unnecessary current limitation and maintaining print speed.
Solution Approach 2:
Different control strategies are applied to different heating regions based on their specific requirements. Image portions receive higher energizing duty to ensure proper fixing quality, while non-image portions receive reduced energizing duty to save energy. This local differentiation resolves the contradiction by allowing high current where needed and low current where not needed, preventing overall current limitation while maintaining productivity.
2Loss of energy
If heating temperature of non-image portions is reduced for energy saving, then energy consumption decreases, but requires complex control of multiple heating regions
Solution Approach 1:
The energizing duty of each heating element group is dynamically adjusted based on real-time detection of current consumption and the specific requirements of each heating region. The control portion continuously monitors and modifies the power supply to heating elements, enabling flexible energy management that reduces consumption in non-image portions while maintaining necessary heating in image portions, all within a unified dynamic control framework.
Solution Approach 2:
A feedback mechanism is implemented where the control portion detects current consumption and adjusts the energizing duty of heating elements accordingly. This feedback loop enables the system to automatically balance energy saving goals with heating requirements, reducing energy consumption in non-image portions while ensuring adequate heating in image portions, without requiring overly complex manual control.
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 allows for minimizing print speed drops while preventing unnecessary current limitations, ensuring efficient energy use and maintaining productivity by dynamically adjusting power distribution across heating elements.
Implementation Method 1
a plurality of heating elements which heat the heating regions respectively are disposed in the longitudinal direction
Data Source
AI summary
In an image forming apparatus, in continuous image formation in which images are continuously formed and fixed on a plurality of recording materials in a fixing portion, with a period from start of the continuous image formation on a first recording material to arrival thereof at the fixing unit being regarded as a first period, and with a period from the arrival of the first recording material at the fixing portion to the end of the continuous image formation being regarded as a second period, a second maximum energizing duty that is set when the control portion supplies power to a plurality of heating elements in the second period is higher than a first maximum energizing duty that is set when the control portion supplies power to the plurality of heating elements in the first period.