Fuser Controller Cooling Threshold by Sheet Size
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Solution Overview
Problem
Conventional image forming apparatuses face temperature rise issues at the end portions of the heating member when printing sheets of different sizes, particularly when an A6 sheet is fed in portrait orientation, as they lack sensors to detect sheet width, leading to inefficient temperature control and reduced printing speed.
Innovation Solution
An image forming apparatus with a temperature sensor to detect the temperature of the heating member's end portions, a controller to adjust the conveyance speed and cooling threshold based on sheet size settings, and a fuser with a heating member and pressure member to thermally fix toner images while preventing excessive temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the conveyance speed is reduced to prevent temperature rise at the end portions of the heating member, then the temperature control is improved, but the printing speed is reduced
Solution Approach 1:
The cooling threshold is dynamically adjusted based on sheet size parameters. When a narrow-width sheet is detected, the cooling threshold is lowered, which triggers the cooling process at appropriate temperatures without requiring speed reduction, thus preventing temperature rise while maintaining printing speed
Solution Approach 2:
The system uses sheet size detection feedback to adjust the cooling threshold adaptively. The controller detects the sheet width and modifies the cooling threshold accordingly, enabling precise temperature control at the heating member end portions without unnecessary speed reduction
2Measurement precision
If a sheet sensor is added to detect sheet width, then the temperature control precision is improved, but the device cost increases
Solution Approach 1:
The existing sheet sensor that detects sheet length in the conveyance direction is made multi-functional by reusing it to infer sheet width information. The controller determines sheet width based on the relationship between detected length and selected sheet size settings, eliminating the need for additional width detection sensors
Solution Approach 2:
The system uses its existing detection capability and job setting information to self-determine sheet width without external assistance from additional sensors. The controller cross-references the detected sheet length with the selected sheet size to infer the width dimension, making the system self-sufficient
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
The solution effectively prevents temperature rise at the heating member's end portions without reducing conveyance speed, allowing for efficient printing by adjusting cooling thresholds and conveyance speeds based on sheet size, ensuring consistent image quality.
Implementation Method 1
a temperature sensor that detects a temperature of an end portion of the heating member
Implementation Method 2
a heating member; a pressure member that nips a sheet with a toner image formed thereon in combination with the heating member
Implementation Method 3
execute, if a temperature detected by the temperature sensor becomes equal to or higher than a cooling threshold during execution of the printing process, a cooling process to restrain a rise in temperature of the heating member
Data Source
AI summary
An image forming apparatus includes a controller configured to identify a selected sheet size setting as defined by a dimension in the width direction and a dimension in the conveyance direction, set a cooling threshold at a first threshold if the selected sheet size setting is a first size having a dimension in the width direction larger than a predetermined dimension, and a dimension in the conveyance direction larger than the dimension in the width direction, and set the cooling threshold at a second threshold lower than the first threshold if the selected sheet size setting is a second size having a dimension in the width direction that is the same as the dimension in the width direction of the first size, and a dimension in the conveyance direction smaller than the dimension in the width direction.