Image Heating Heater With Independent Blocks for Edge Overheat Control
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Solution Overview
Problem
Existing image heating devices in copiers and printers experience temperature rise at non-sheet-passing portions, leading to component damage and toner offset, despite the use of positive temperature coefficient (PTC) resistors to manage heat generation.
Innovation Solution
A heater design with multiple heating blocks, each comprising a first and second conductive element and a heat generating resistor, allowing independent power control of these blocks, and employing diagonal power feeding to reduce temperature rise at non-sheet-passing areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater with PTC resistor is used to prevent temperature rise at non-sheet-passing portion, then temperature control is improved, but heat generation at non-sheet-passing portion cannot be completely eliminated
Solution Approach 1:
The heater is divided into multiple heating blocks (first heating block, second heating block, third heating block) along the paper conveying direction. Each heating block can be independently controlled, allowing selective activation of only the necessary heating portions while eliminating heat generation at non-sheet-passing areas.
Solution Approach 2:
Different heating blocks are activated based on the specific printing task requirements. For example, when printing small size paper, only the central heating block is activated, while edge heating blocks remain inactive, thereby preventing heat generation at non-sheet-passing portions.
2Temperature
If multiple heating blocks with independent power control are implemented, then temperature distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The heater is segmented into multiple independently controllable heating blocks, each with its own power control circuit. This segmentation enables precise temperature control and uniform heat distribution across different regions of the heater.
Solution Approach 2:
The power supply to each heating block can be dynamically adjusted independently based on real-time temperature feedback and printing task requirements, enabling adaptive temperature control to achieve uniform heat distribution.
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 enhancing safety by reducing temperature fluctuations and preventing component damage.
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
The resistance of the heat generating resistor at the non-sheet-passing portion increases when the temperature of the non-sheet-passing portion increases. Thus, the heat generation at the non-sheet-passing portion can be decreased by reducing the electric current that passes through the heat generating resistor at the non-sheet-passing portion.
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.