Fixing-Unit Roller Porous Elastic Layer Nip Pressure
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Solution Overview
Problem
Conventional fixing-unit rollers with low hardness sponge layers suffer from short endurance due to external forces, leading to a narrow usable range and insufficient image fixation, as they cannot maintain a predetermined nip pressure effectively.
Innovation Solution
A fixing-unit roller with an elastic layer formed from a porous material containing cells between 0.1 μm and 50 μm in size, where the area occupied by composite cells in a cross section is between 60% and 70%, providing even stress distribution and increased endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a low hardness sponge layer is used to reduce warm-up time and provide wide nip width, then the roller achieves compactness and fast heating, but the sponge layer has low endurance and cannot maintain predetermined nip pressure
Solution Approach 1:
The patent applies porous materials by forming an elastic layer with a controlled foam structure containing numerous small cells (0.1-50 μm) distributed throughout the layer. This porous structure provides thermal insulation to reduce warm-up time while the controlled cell size and distribution maintain structural integrity and endurance under operational pressure, resolving the contradiction between fast heating and durability.
Solution Approach 2:
The patent changes physical parameters by controlling cell size (0.1-50 μm), cell distribution (60-70% area ratio of composite cells), and porosity of the foam structure. These parameter changes optimize both thermal properties (for reduced warm-up time) and mechanical properties (for maintained nip pressure and endurance), allowing the elastic layer to simultaneously achieve compactness, fast heating, and high reliability.
2Shape
If a low hardness sponge layer is used to provide wide nip width, then the roller achieves compact design, but the sponge layer damages easily under external force and hardness decreases sharply
Solution Approach 1:
The patent uses porous materials with a specifically controlled foam structure where numerous small cells (0.1-50 μm) are distributed throughout the elastic layer. This porous structure allows the material to be compliant enough to provide wide nip width for compact design while the controlled cell size and high density of cells distribute applied forces evenly, preventing localized damage and maintaining hardness under external force.
Solution Approach 2:
The elastic layer functions as a composite material combining the metal core bar with a foam-based porous material. This composite structure integrates the rigidity of the metal core with the compliance and force-distributing properties of the controlled foam structure, enabling the roller to maintain wide nip width while resisting damage from external forces and maintaining consistent hardness.
3Volume of moving object
If the roller diameter is reduced to achieve compactness, then the device size is reduced, but maintaining wide nip width and sufficient image fixation becomes difficult
Solution Approach 1:
The patent applies porous materials by creating an elastic layer with controlled foam structure (0.1-50 μm cells at 60-70% composite cell area ratio) that compensates for the reduced roller diameter. The porous structure provides enhanced compliance and stress distribution, allowing a smaller roller to still achieve sufficient nip width and effective image fixation through optimized material properties rather than relying solely on larger dimensions.
Data Source
AI summary
A fixing-unit roller includes: a core bar; and an elastic layer formed on an outer peripheral surface of the core bar. The elastic layer is formed from a porous material that contains a plurality of cells. Cells in a cross section obtained by cutting across the porous material are 0.1 μm or greater and 50 μm or less in size. A ratio of an area occupied by composite cells, which are made of partially-overlapping spherical cells, in a 200-μm square in the cross section to an area of the square is 60% or greater and 70% or less.