Fixing Device Heater Control via Sheet Edge Position
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Solution Overview
Problem
The existing image forming apparatuses face challenges in providing an appropriate amount of heat to the heating member, particularly with the second heater, due to the position of the sheet edge in the width direction, leading to insufficient heat application in areas where the sheet does not directly contact the heating member.
Innovation Solution
The apparatus employs a configuration with a first heater and a second heater, where the first heater heats the center area more strongly than the end areas, and the second heater heats the end areas more strongly than the center, with the second heater's peak output positioned within the largest sheet area. A controller determines the second target temperature based on the edge position relative to the peak position of the second heater's output, ensuring adequate heat application regardless of the sheet's edge position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the second heater is used to heat the end area of the heating member, then the heat application to the end area is improved, but the temperature control becomes insufficient when the sheet edge position varies
Solution Approach 1:
The patent implements dynamic temperature control by adjusting the second target temperature Tb based on the detected edge position of the sheet. When the edge position varies, the controller dynamically modifies Tb to ensure that the end area receives appropriate heat regardless of sheet position, thereby maintaining reliable temperature control.
Solution Approach 2:
The patent employs feedback control by using an edge position detection device to detect the actual edge position of the sheet, then using this information to adjust the second target temperature Tb. This closed-loop feedback mechanism ensures that temperature control remains reliable even when sheet edge positions vary during operation.
2Adaptability or versatility
If the second heater's output is increased to cover larger sheet areas, then the heat application to varying sheet sizes is improved, but energy consumption increases
Solution Approach 1:
The patent applies local quality by having different heaters (first heater for center area, second heater for end area) with different output characteristics suited to their respective regions. The second heater is specifically designed with output characteristics matched to the sheet area it needs to cover, avoiding unnecessary energy consumption in areas where heat is not required.
Solution Approach 2:
The patent changes the parameter of target temperature dynamically based on sheet edge position. By adjusting the second target temperature Tb according to the detected edge position, the system optimizes energy consumption by applying heat only where and when needed, rather than maintaining high output for all possible sheet positions.
3Stability of the object's composition
If multiple heaters with different output characteristics are used, then the temperature distribution uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent segments the heating function by dividing the heating member into a center area (heated by the first heater) and an end area (heated by the second heater). Each heater is responsible for a specific region, allowing independent optimization of temperature distribution in each zone without requiring complex coordinated control of the entire heating system.
Solution Approach 2:
The controller serves multiple functions by both detecting the edge position of the sheet and determining the appropriate second target temperature Tb based on that position. This multi-functionality reduces device complexity by consolidating control logic into a single controller rather than requiring separate detection and control systems.
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 ensures that an appropriate amount of heat is consistently applied to the heating member, preventing heat shortages and maintaining optimal temperature control for fixing toner images across varying sheet sizes and positions.
Implementation Method 1
The first heater is configured to heat a center area of the heating member in the particular direction more strongly than an end area of the heating member
Implementation Method 2
The first heater is configured to heat a center area of the heating member in the particular direction more strongly than an end area of the heating member
Implementation Method 3
The second heater is configured to heat the end area more strongly than the center area
Implementation Method 4
The second heater is configured to heat the end area more strongly than the center area
Implementation Method 5
The heating member is configured to heat the sheet
Implementation Method 6
The heating member is configured to heat the sheet
Data Source
AI summary
A second heater has such an output that a peak position in a particular direction is located within a largest sheet area. The largest sheet area is an area in which a heating member contacts a sheet having a largest size in the particular direction that is conveyable through a fixing device. A first sensor detects temperature of a center area. A second sensor detects temperature at an outside position in an end area. The outside position is outside the largest sheet area in the particular direction. A controller controls a first heater such that a first detection temperature detected by the first sensor becomes a first target temperature; controls the second heater such that a second detection temperature detected by the second sensor becomes a second target temperature; and determines the second target temperature based on an edge position of a sheet relative to the peak position.