Heating Device Temperature Sensor Placement for Fixing Belt Control
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining precise temperature control for heating devices, particularly in non-conveyance spans and when dealing with sheets of varying widths, which can lead to overheating and plastic deformation of the fixing belt due to improper sheet alignment.
Innovation Solution
The implementation of a heating device with a configuration that includes three temperature sensors: a first and second temperature sensor positioned outboard from increased and decreased conveyance spans respectively, and a third sensor at the center, to detect temperature variations and sheet alignment, allowing for controlled heat generation and preventing overheating and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature sensors are used to detect temperature at different positions, then temperature control precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The heating area is segmented into multiple zones (conveyance span and non-conveyance span) with temperature sensors strategically placed at different positions. The first temperature sensor detects temperature in the non-conveyance span, while the second temperature sensor detects temperature in the conveyance span, allowing independent temperature control for each zone to prevent overheating and deformation.
Solution Approach 2:
The patent introduces a control unit as an intermediary that receives temperature data from multiple sensors and adjusts heater output accordingly. This mediator coordinates the complex temperature control task, managing the relationship between multiple sensors and the heating element to achieve precise temperature control without requiring direct manual intervention.
2Measurement precision
If temperature sensors are placed within the conveyance span, then sheet temperature monitoring is improved, but the sensors interfere with sheet conveyance and increase device size
Solution Approach 1:
Temperature sensors are placed at specific local positions (one in the conveyance span and one in the non-conveyance span) rather than uniformly distributed. This localized placement allows temperature monitoring where most needed while minimizing interference with sheet conveyance and reducing overall device footprint.
3Adaptability or versatility
If the heater spans the entire width to handle various sheet sizes, then adaptability is improved, but heat distribution uniformity deteriorates
Solution Approach 1:
The patent implements dynamic temperature control where the control unit adjusts heater output based on real-time temperature feedback from sensors positioned at different spans. This dynamic adjustment compensates for varying heat distribution patterns when processing different sheet sizes, maintaining uniformity across the entire heating area while preserving adaptability to various sheet dimensions.
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 configuration effectively reduces manufacturing costs and device size by detecting temperature increases and sheet shifting with fewer sensors, ensuring precise temperature control and preventing overheating and deformation of the fixing belt.
Implementation Method 1
A heater heats at least one of the first rotator and the second rotator
Implementation Method 2
A first temperature sensor detects a temperature of at least one of the first rotator, the second rotator, and the heater
Data Source
AI summary
A heating device includes a first temperature sensor and a second temperature sensor that detect a temperature of at least one of a first rotator, a second rotator, and a heater that heats at least one of the first rotator and the second rotator. The first temperature sensor is disposed outboard from an increased conveyance span where an increased size sheet having an increased width in a longitudinal direction of the heater is conveyed. The second temperature sensor is disposed outboard from a decreased conveyance span where a decreased size sheet having a decreased width in the longitudinal direction of the heater is conveyed. The decreased conveyance span is smaller than the increased conveyance span. The second temperature sensor is disposed within the increased conveyance span and disposed opposite the first temperature sensor via a center of the increased conveyance span in the longitudinal direction of the heater.