Segmented PTC Heater Layout for Non-Sheet Edge Overheating
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Solution Overview
Problem
Existing image heating devices experience temperature rise at non-sheet-passing portions, leading to potential damage and toner offset issues due to uneven heat distribution and current flow through resistors.
Innovation Solution
A heater design with multiple heating blocks, each comprising a set of conductive elements and a heat generating resistor with positive temperature coefficient, allowing independent power control to each block, and diagonal power feeding to reduce temperature rise at non-sheet-passing areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single heater with uniform resistance is used, then the heater structure is simple, but temperature rise occurs at non-sheet-passing portions leading to component damage and toner offset
Solution Approach 1:
The heater is divided into multiple heating blocks (first heating block, second heating block, etc.) along the conveying direction. Each heating block has independent power supply terminals and can be controlled separately. This segmentation allows different portions of the heater to operate at different power levels, preventing temperature rise at non-sheet-passing portions while maintaining heating efficiency at sheet-passing portions.
2Productivity
If power is supplied to all heating blocks simultaneously, then heating efficiency is maximized, but temperature rise occurs at non-sheet-passing portions
Solution Approach 1:
The power supply to each heating block is made dynamic and adjustable. The controller can independently control the power supplied to each heating block based on the actual heating needs of different portions. This dynamic control allows the system to adapt power distribution to prevent temperature rise at non-sheet-passing portions while maintaining efficient heating where needed.
Solution Approach 2:
Different heating blocks are assigned different power levels based on their specific functional requirements. Heating blocks corresponding to sheet-passing portions receive adequate power for efficient heating, while heating blocks corresponding to non-sheet-passing portions receive reduced or no power to prevent temperature rise. This local differentiation of heating intensity resolves the contradiction between overall heating efficiency and localized 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
Effectively prevents temperature rise at non-sheet-passing portions, ensuring uniform heat distribution and enhanced safety by reducing current flow and temperature imbalance, thereby protecting the device and preventing toner offset.
Implementation Method 1
a heat generating resistor provided between the first conductive element and the second conductive element and showing a positive temperature characteristic of resistance, which generates heat when power is supplied via the first conductive element and the second conductive element
Implementation Method 2
a heat generating resistor provided between the first conductive element and the second conductive element and showing a positive temperature characteristic of resistance
Data Source
AI summary
A heater of the present invention includes jointed heat generating resistors having a positive temperature characteristic of resistance and provided between a first conductive element and a second conductive element on a substrate in a longitudinal direction of the substrate, and a plurality of heating blocks provided in the longitudinal direction, each of which is a set of the first conductive element, the second conductive element, and the heat generating resistor, and power supplied to at least one of the plurality of heating blocks can be controlled independent of other heating blocks.