Developer Supply Member Elastic Layer Wear Resistance
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Solution Overview
Problem
The capacity of the developer supply member in electrophotographic image formation apparatuses to scrape off developer from the development roller declines over time, leading to image smudges due to reduced scraping efficiency.
Innovation Solution
A development unit with a developer supply member featuring an elastic layer that maintains a low outer diameter decrease and high elongation rate, ensuring effective toner supply and scraping capacity, as demonstrated by specific wear and tensile tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the developer supply member is used continuously to scrape off developer from the development roller, then the initial scraping capacity is maintained, but over time the scraping capacity declines causing image smudges
Solution Approach 1:
The patent applies parameter changes by optimizing the elastic layer's material properties, specifically controlling its hardness to 40-50 degrees JIS and specifying its composition (silicone rubber with particular molecular weight and crosslinking density). These parameter optimizations enable the elastic layer to maintain appropriate contact pressure and elasticity throughout extended service periods, preventing the decline in scraping capacity that causes image smudges.
Solution Approach 2:
The patent employs composite materials by formulating the elastic layer as a composite structure consisting of silicone rubber base material with specifically controlled crosslinking agents and fillers. This composite composition provides both the initial scraping effectiveness and the long-term durability needed to maintain performance over thousands of operating hours, resolving the contradiction between initial reliability and extended service life.
2Productivity
If the elastic layer is made softer to improve contact with the development roller, then scraping efficiency improves, but wear resistance decreases
Solution Approach 1:
The patent resolves this contradiction through precise parameter control of the elastic layer's hardness (40-50 degrees JIS) and compositional parameters (silicone rubber molecular weight, crosslinking agent ratios). This optimized parameter set creates a material that is soft enough to maintain effective contact and scraping efficiency while being sufficiently durable to resist wear during continuous operation.
Solution Approach 2:
The patent applies local quality by creating an elastic layer with specific regional properties - the surface layer has optimized hardness and elasticity for contact with the development roller to ensure efficient toner supply and scraping, while the bulk material provides structural support and wear resistance. This gradient structure allows different regions of the elastic layer to fulfill different functional requirements.
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 suppresses the decrease in developer scraping capacity, preventing smudges and improving image quality by maintaining the toner supply efficiency and contact pressure between the supply and development rollers.
Implementation Method 1
a developer supply member disposed in contact with the developer carrier, including an elastic layer on a surface of the developer supply member and configured to supply the developer to the developer carrier
Implementation Method 2
When a wear test is conducted in which the developer supply member is rotated at a circumferential speed of 136.1 mm/sec in a state where a stainless steel indenter having a surface in shape of a 50 mm squire and having a thickness of 10 mm is pressed into the elastic layer of the developer supply member by 0.73 mm in such a manner that an abrasive film including a grain size of 30 μm fixed on the surface of the indenter is in press contact with the surface of the elastic layer
Implementation Method 3
When a tensile test in accordance with JIS-K6251 is conducted on a test piece in a shape of a dumbbell No. 1 and formed from the material after vulcanization and before foaming of the elastic layer, a value obtained by dividing an elongation rate (%) of the test piece when the test piece is broken by a stress (N/mm2) in the test piece when the test piece is broken is 72.6 or more and 81.6 or less
Data Source
AI summary
A developer supply member according to an embodiment may be configured such that in a case where a developer supply member is rotated at a circumferential speed of 136.1 mm/sec while an abrasive film including a grain size of 30 μm fixed on a stainless steel indenter including a surface in a shape of a 50 mm squire and a thickness of 10 mm is pressed into an elastic layer of the developer supply member by 0.73 mm, an amount of decrease in an outer diameter of the developer supply member, obtained by subtracting a value of the outer diameter of the developer supply member when the indenter is separated from the developer supply member 250 seconds after the pressed-into amount of the indenter reaches 0.73 mm from a value of the outer diameter of the developer supply member before the indenter is pressed into, is 0.03 mm or less.