Image Forming Apparatus Pressure Roller Velocity Control
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Solution Overview
Problem
Image forming apparatuses face issues with excessive temperature increases in the fixing device due to thermistor failures, leading to potential sheet conveyance failures due to mismatched linear velocities between the pressure roller and the fixing belt.
Innovation Solution
The apparatus includes a fixing device with a heater, pressure roller, and temperature control sections to measure and adjust the linear velocity of the pressure roller based on temperature tendencies, ensuring consistent conveyance speed by accounting for temperature changes and expansions of the pressure roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure roller and fixing belt operate at fixed linear velocities, then the device complexity is reduced, but sheet conveyance failures occur due to temperature-induced velocity mismatch
Solution Approach 1:
The patent applies dynamics by making the pressure roller's linear velocity variable rather than fixed. The velocity is dynamically adjusted based on real-time temperature measurements from the fixing device, allowing the system to adapt to thermal expansion changes and maintain reliable sheet conveyance throughout the fixing process.
Solution Approach 2:
The patent implements feedback control by continuously measuring the temperature of the fixing device and using this information to adjust the pressure roller's linear velocity. This closed-loop system ensures that velocity adjustments are based on actual thermal conditions, resolving the contradiction between reliability and complexity through intelligent control.
2Reliability
If the pressure roller linear velocity is adjusted to compensate for temperature changes, then sheet conveyance reliability is improved, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent applies parameter changes by modifying the linear velocity parameter of the pressure roller based on temperature measurements. The system changes the velocity parameter dynamically to compensate for thermal expansion, ensuring consistent conveyance speed while managing complexity through targeted parameter adjustment rather than complete system redesign.
Solution Approach 2:
The patent replaces purely mechanical velocity control with a hybrid system that incorporates temperature sensing and electronic control. This substitution allows for more precise velocity adjustment based on thermal conditions, improving conveyance consistency while containing complexity through modern control electronics rather than complex mechanical adjustments.
3Reliability
If temperature measurements and velocity adjustments are performed continuously, then conveyance reliability is maintained, but energy consumption and processing time increase
Solution Approach 1:
The patent applies preliminary action by measuring the temperature of the fixing device before sheet conveyance begins and using this advance information to pre-adjust the pressure roller's linear velocity. This prevents conveyance issues before they occur, maintaining reliability while reducing the time needed for real-time corrections.
Solution Approach 2:
The patent implements periodic action by performing temperature measurements at specific intervals rather than continuously. The system measures temperature at key points in the fixing process and adjusts velocity accordingly, maintaining conveyance stability while reducing the cumulative time and energy required for temperature monitoring and 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 solution effectively prevents sheet conveyance failures by dynamically controlling the pressure roller's linear velocity, maintaining optimal temperature management and ensuring reliable operation of the image forming process.
Implementation Method 1
The heater heats the fixing belt
Implementation Method 2
The fixing belt heats a toner image transferred to a sheet to fix the toner image to the sheet
Implementation Method 3
The pressure roller rotates the fixing belt while in contact with the fixing belt
Implementation Method 4
accounting for temperature changes and expansions of the pressure roller
Data Source
AI summary
A duration measuring section measures a plurality of times. A temperature measuring section measures a temperature of a heater at each of the times. A temperature information outputting section outputs heater temperature information. A temperature tendency computing section outputs temperature tendency information of the heater. A drive controller outputs linear velocity information for controlling the linear velocity of a pressure roller. A pressure roller drive section drives the pressure roller.