Fixing Roller Dual-Heater Control for Abnormal Energization
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face issues with abnormal energization states leading to rapid temperature rises in fixing devices, potentially damaging components due to insufficient power control and inefficient standby mode power management.
Innovation Solution
The image forming apparatus employs a dual-heater system with a control unit that manages power distribution between a first and second heater, allowing power to one heater in a fixing state and both in a standby state, and includes a control mechanism to stop power to specific heaters based on temperature and rotation speed detection to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large amount of power is supplied to the fixing device to enable high-speed image forming, then productivity is improved, but the risk of abnormal energization and component damage increases
Solution Approach 1:
The heating roller is divided into multiple independent heating zones, each controlled by separate heating elements. This segmentation allows selective activation of heating zones based on operational requirements, enabling high power delivery when needed while limiting power during standby or low-demand periods, thus resolving the contradiction between productivity and reliability
Solution Approach 2:
The fixing device implements dynamic power control where the heating power is adjusted based on the rotation speed of the heating roller and the operational state (standby vs. image forming). The control unit dynamically modifies power supply to prevent abnormal energization while maintaining high-speed capability when required, addressing the reliability-productivity trade-off
2Duration of action of stationary object
If the heating roller rotates slowly in standby mode to reduce wear, then the rotation member lifespan is improved, but the temperature rise in the fixing device increases due to insufficient heat dissipation
Solution Approach 1:
The system performs preliminary heating actions during standby mode by activating specific heating zones before the heating roller reaches optimal rotation speed. This ensures that the fixing device maintains appropriate temperature levels even during slow rotation, preventing excessive temperature rise while still allowing the roller to rotate slowly for extended lifespan
Solution Approach 2:
Different zones of the heating roller are assigned different heating characteristics and power levels. During standby mode, only specific local zones are activated to maintain minimal necessary temperature, while during image forming, all zones operate at full capacity. This local differentiation resolves the contradiction between extended lifespan and temperature control
3Reliability
If power is quickly suppressed during abnormal energization to prevent damage, then component safety is improved, but the temperature of the fixing device rises greatly during the detection-to-stop period
Solution Approach 1:
The control system implements rapid power suppression that skips intermediate heating stages and directly transitions to minimal power mode upon detecting abnormal conditions. This rushing through of the normal heating sequence minimizes the time during which high power is delivered, thereby limiting temperature rise while still providing component protection
Solution Approach 2:
The system maintains a baseline level of heating power even during abnormal energization states, rather than completely shutting down. This beforehand cushioning prevents excessive temperature rise during the detection-to-stop period while still being sufficient to protect components from damage, resolving the contradiction between component protection and temperature 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 effectively prevents component damage by managing power supply during abnormal energization states and optimizing standby mode power usage, minimizing temperature overshoot and extending component lifespan.
Implementation Method 1
The halogen heater transmits radiant heat generated by energization to the heating rotation member
Implementation Method 2
The fixing unit heats and pressurizes the recording medium, onto which the toner image has been transferred, to thereby fix the toner image to the recording medium
Data Source
AI summary
An image forming apparatus includes: a heating unit including a heating rotation member configured to heat a recording medium: a pressure rotation member which contacts the heating rotation member to form a nip portion to fix a toner image to the recording medium, a heat source configured to heat the heating rotation member, the heat source including a first heater and a second heater, and a control unit configured to control the first heater and the second heater, wherein the image forming unit is operable to transition to: a fixing state in which an operation to fix the toner image to the recording medium is performed by receiving a job; and a standby state, to wait for the job, in which an operation to fix the toner image to the recording medium is not performed.