Fixing Device Current Control in Image Forming Apparatus
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Solution Overview
Problem
Image forming apparatuses face challenges in managing current consumption to prevent exceeding the maximum current limit from the commercial power supply, especially during the printing period, due to increased power demands from faster motors and colorization, which can lead to reduced processing performance and fixability issues.
Innovation Solution
An image forming apparatus equipped with a current detection circuit that detects input current and adjusts the conveyance interval of recording material to the fixing device, extending it when the current exceeds a predetermined value to maintain the fixing device's temperature and restrict the current to the fixing device when necessary, ensuring the total current does not exceed the supply limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the image forming apparatus uses faster/larger motors and multiple motors for colorization, then the image forming speed and functionality are improved, but the current consumption increases and may exceed the maximum current limit from the commercial power supply
Solution Approach 1:
The patent implements dynamic current management by continuously monitoring the total current consumption and adjusting the fixing device's current allocation in real-time. The current allocation to the fixing device is made variable based on the operational state and total current consumption, allowing the system to adapt to changing power demands while maintaining image forming speed and functionality.
Solution Approach 2:
The patent changes the parameter of current allocation to the fixing device based on total current consumption. When total current exceeds the maximum limit, the system reduces the current allocated to the fixing device, thereby controlling overall power consumption while maintaining operational capability.
2Temperature
If the fixing device consumes large current during warm-up period, then the fixing device reaches operational temperature faster, but the total current may exceed the maximum current limit from the commercial power supply
Solution Approach 1:
The patent implements preliminary monitoring of total current consumption before allowing the fixing device to draw full current during warm-up. The system预先 detects the total current state and prepares to adjust the fixing device's current allocation if the maximum current limit is approached, preventing current overload while enabling efficient warm-up when power is available.
Solution Approach 2:
The patent employs feedback control by continuously monitoring total current consumption and using this information to adjust the current allocated to the fixing device. The current allocation is dynamically adjusted based on the detected total current state, creating a closed-loop control system that balances warm-up efficiency with power supply constraints.
3Use of energy by moving object
If the current to the fixing device is restricted to prevent exceeding maximum current limit, then the current consumption is controlled, but the fixing device temperature may drop below the predetermined temperature affecting fixability
Solution Approach 1:
The patent implements dynamic current allocation that adjusts the current to the fixing device based on real-time total current consumption. The current allocation is made variable rather than fixed, allowing the system to provide sufficient current for maintainable temperature while controlling overall power consumption within the maximum current limit.
Solution Approach 2:
The patent employs feedback control to continuously monitor total current consumption and adjust the fixing device's current allocation accordingly. This closed-loop control ensures that the fixing device receives adequate current to maintain operational temperature while preventing total current from exceeding the maximum limit, thus balancing power control with fixability reliability.
4Productivity
If multiple loads are activated simultaneously during the printing period, then the processing capability and productivity are improved, but the total current may exceed the maximum current limit from the commercial power supply
Solution Approach 1:
The patent changes the parameter of current allocation to the fixing device based on the operational state and total current consumption. When multiple loads are activated and total current approaches the maximum limit, the system adjusts the current allocation parameter to prevent exceeding the power supply capacity, thereby enabling high productivity operation within safe current constraints.
Solution Approach 2:
The patent implements dynamic current management that continuously adapts the current allocation to the fixing device based on the operational state and total current consumption. This dynamic adjustment allows multiple loads to operate simultaneously while maintaining total current within the maximum limit, preserving productivity while preventing power overload.
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 solution effectively suppresses the input current to within predetermined limits, maintaining the processing performance and fixability of the image forming apparatus while preventing excessive current consumption, thereby ensuring stable operation within the commercial power supply constraints.
Implementation Method 1
a current detection circuit for detecting an input current from a commercial power supply to the apparatus
Implementation Method 2
a fixing device for fixing the toner image onto the recording paper by heating and pressurizing, under a predetermined fixing process condition, the recording paper
Data Source
AI summary
The image forming apparatus includes a current detection circuit for detecting an input current from the commercial power supply to the apparatus, in which: when a current detected by the current detection circuit exceeds a predetermined value, a maximum current suppliable to a fixing portion is restricted; and when a temperature of the fixing portion falls below, in a situation where the maximum current suppliable to the fixing portion is restricted, the predetermined temperature lower than a control target temperature, a conveyance interval of a recording material conveyed to the fixing portion is extended. In the image forming apparatus, even when a consumption current of the image forming apparatus is increased during successive image formation, it is capable of controlling the consumption current so as not to exceed a maximum current of a commercial power supply, securing desired fixability, and minimizing decline of image forming performance.