Dual-Layer Pressure Roller for Rapid Heating and Gloss Control
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Solution Overview
Problem
Conventional image heating devices face challenges in achieving both rapid rising time and preventing temperature rise at non-paper-passing regions while maintaining image quality, particularly with the introduction of thinner surface elastic layers which can lead to pressure unevenness and gloss unevenness in output images.
Innovation Solution
A pressure roller with a mandrel, a first elastic layer made of open-cell foam rubber, and a second elastic layer made of solid rubber, where the first elastic layer has a thickness of at least 50 μm and not more than 500 μm, is used in an image heating device to reduce rising time and prevent temperature rise at non-paper-passing regions, thereby minimizing gloss unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the first elastic layer is made thinner to reduce rising time, then the rising time is reduced, but pressure unevenness and gloss unevenness occur in output images
Solution Approach 1:
The pressure roller uses a composite structure with two different elastic layers: a first elastic layer (50-500 μm thick) made of material with lower thermal conductivity for rapid heating and insulation, and a second elastic layer made of material with higher thermal conductivity for thermal diffusion and pressure uniformity. This composite structure resolves the contradiction by combining materials with complementary thermal properties.
Solution Approach 2:
Different regions of the pressure roller are assigned different thermal conductivity properties to fulfill different functions. The first elastic layer (outer layer) has lower thermal conductivity to prevent heat diffusion and enable quick rising, while the second elastic layer (inner layer) has higher thermal conductivity to ensure uniform pressure distribution and prevent gloss unevenness. This local differentiation of material properties resolves the technical contradiction.
2Loss of time
If the first elastic layer is made thinner to reduce rising time, then the rising time is reduced, but temperature rises excessively at non-paper-passing regions
Solution Approach 1:
The dual-layer elastic structure combines materials with different thermal conductivities to achieve both rapid heating and thermal management. The first elastic layer's lower thermal conductivity enables quick temperature rise, while the second elastic layer's higher thermal conductivity prevents excessive temperature accumulation at non-paper-passing regions through lateral heat diffusion.
Solution Approach 2:
The pressure roller applies different thermal conductivity characteristics to different layers: the outer first elastic layer provides thermal insulation for rapid heating response, while the inner second elastic layer provides thermal conduction pathways to dissipate heat from non-paper-passing regions, preventing excessive temperature rise.
3Loss of time
If heat is supplied more actively to reduce rising time, then the rising time is reduced, but temperature rise at non-paper-passing part increases
Solution Approach 1:
The composite elastic layer structure allows aggressive heating to achieve rapid rising time while the second elastic layer with higher thermal conductivity acts as a heat distribution network, preventing localized overheating at non-paper-passing regions by conducting heat laterally across the roller surface.
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 reduces rising time and prevents temperature rise at non-paper-passing regions, resulting in improved image quality with reduced gloss unevenness, even at higher printing speeds.
Implementation Method 1
the first elastic layer is made of rubber having open-cell voids... thermal diffusion from the surface to the inside of the pressure roller can be prevented
Implementation Method 2
the first elastic layer is made of rubber having open-cell voids
Implementation Method 3
the second elastic layer is made of solid rubber... thermal diffusion into the pressure roller is prevented
Data Source
AI summary
Provided is a pressure roller for an image heating device that forms a nip part together with a heating member, the pressure roller including at least a mandrel, a first elastic layer, and a second elastic layer provided between the mandrel and the first elastic layer, wherein the first elastic layer has open-cell voids, is made of rubber, and has a thickness of at least 50 μm and less than 500 μm, and the second elastic layer is made of solid rubber.