Heater Substrate Thermistor Connection Direction
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Solution Overview
Problem
Heaters used in image forming apparatuses experience temperature distribution issues along the substrate, leading to thermal expansion and potential cracking, and the existing solutions for temperature control result in printing unevenness due to continuous slidable contact with connecting portions.
Innovation Solution
The heater design includes a substrate with resistance heat-generating elements and thermistors on opposite surfaces, where the connection direction of the thermistor and conductor patterns is along the longitudinal direction, preventing continuous slidable contact and reducing friction with the recording sheet, thereby minimizing temperature gradients and printing unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first connecting portion and the second connecting portion are arranged along the lateral direction of the substrate, then the conductor and thermistor can be connected effectively, but the recording sheet continuously rubs against the projection portions causing printing unevenness
Solution Approach 1:
The patent changes the arrangement direction of the connecting portions from the lateral direction (Y-direction) to the longitudinal direction (X-direction) of the substrate. This dimensional change in arrangement prevents the recording sheet from continuously rubbing against the projection portions during lateral transport, thereby eliminating printing unevenness while maintaining effective electrical connection between the conductor and thermistor.
2Area of stationary object
If the resistance heat-generating element extends in band shape along the longitudinal direction, then heating coverage is improved, but temperature gradient causes thermal expansion and substrate cracking
Solution Approach 1:
The patent employs a feedback mechanism where the thermistor measures the temperature of the substrate and feeds this information back to control the power supply to the resistance heat-generating element. This closed-loop control adjusts the heat generation to maintain uniform temperature distribution across the substrate, preventing excessive temperature gradients that would cause thermal expansion and cracking, while still providing adequate heating coverage.
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 controls temperature distribution, reduces the risk of substrate cracking, and improves printing quality by minimizing friction and unevenness, enhancing the durability and performance of the heater.
Implementation Method 1
The heater causes a resistance heat-generating element formed on one surface of a substrate to generate heat using power supplied from a power supply electrode
Implementation Method 2
a thermistor that measures temperature of the substrate is provided on the other surface thereof
Implementation Method 3
there is a problem that cracks occur in the substrate due to the influence of thermal expansion
Data Source
AI summary
A heater including a rectangular substrate; a resistance heat-generating element that is provided on one surface of the substrate along a longitudinal direction of the substrate; a thermistor that is provided on the other surface, which is a rear side of the one surface of the substrate, and measures temperature of the substrate; and a conductor that is provided on the other surface of the substrate, is extended up to an end portion of the substrate from the thermistor along the longitudinal direction of the substrate, and supplies power to the thermistor. A first connecting portion and a second connecting portion, which are connected to the conductor, are provided at both ends of the thermistor. A connection direction, in which the first connecting portion and the second connecting portion are arranged on the other surface of the substrate, is different from a lateral direction of the substrate.