Flexible Imaging Member Flatness via Charge Transport Layer Plasticizer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flexible electrophotographic imaging members face issues with curling due to thermal contraction mismatch between the charge transport layer and the substrate, leading to the need for an anticurl back coating, which causes strain, premature fatigue, and print quality defects like ghosting images from amine contamination.
Innovation Solution
The development of flexible electrophotographic imaging members with a charge transport layer formulated using a novel A-B diblock copolymer or binary polymer blend with a bisphenol polycarbonate, incorporating a plasticizer to relieve internal stress and resist amine species, eliminating the need for an anticurl back coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If an anticurl back coating is applied to counteract thermal contraction mismatch, then imaging member flatness is improved, but the coating introduces strain and premature fatigue
Solution Approach 1:
The invention removes the anticurl back coating layer entirely from the imaging member structure. By reformulating the charge transport layer with specific polymers and plasticizers, the patent achieves flatness without requiring the separate anticurl coating, thereby eliminating the strain and fatigue problems associated with that layer.
Solution Approach 2:
The patent modifies the thermal and mechanical parameters of the charge transport layer by incorporating specific plasticizers and polymer blends. These parameter changes allow the charge transport layer itself to accommodate thermal contraction without developing excessive internal stress, eliminating the need for the anticurl back coating.
2Stability of the object's composition
If an anticurl back coating is applied to maintain flatness, then imaging member stability is improved, but strain accumulation causes premature fatigue
Solution Approach 1:
The invention eliminates the anticurl back coating layer that was previously needed to maintain imaging member stability. The reformulated charge transport layer inherently provides dimensional stability through its polymer and plasticizer composition, removing the source of strain accumulation that led to premature fatigue.
Solution Approach 2:
The patent uses composite materials in the charge transport layer, specifically combining polymers with plasticizers in controlled ratios. This composite formulation provides both dimensional stability and flexibility, allowing the layer to withstand thermal cycling without generating the strains that cause fatigue in coated structures.
3Ease of manufacture
If conventional charge transport layer materials are used, then manufacturing simplicity is maintained, but thermal contraction mismatch causes curling
Solution Approach 1:
The patent changes the thermal and mechanical parameters of the charge transport layer by incorporating plasticizers and specific polymer blends. These parameter modifications adjust the thermal contraction characteristics to match the substrate, preventing curling while maintaining a relatively simple manufacturing process that uses conventional coating techniques.
Solution Approach 2:
The invention employs composite materials combining polymers and plasticizers in the charge transport layer. This composite approach allows tuning of thermal contraction properties to match the substrate, preventing curling without requiring complex manufacturing processes or additional coating layers.
4Shape
If plasticizer is incorporated in charge transport layer, then internal stress is relieved and flatness is achieved, but amine species contamination causes ghosting image defects
Solution Approach 1:
The patent carefully controls the type and amount of plasticizer used in the charge transport layer. By selecting plasticizers with appropriate chemical properties and optimizing their concentration, the formulation achieves stress relief and flatness while minimizing the tendency to absorb amine species that cause ghosting defects.
Solution Approach 2:
The invention uses composite formulations combining specific polymers and plasticizers in controlled ratios. This composite approach allows the system to achieve both flatness through stress relief and resistance to amine contamination, as the polymer matrix and plasticizer work together to provide both mechanical and chemical properties.
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 achieves absolute imaging member flatness, enhanced electrical stability, and resolves ghosting image defects by effectively managing curl and strain, while maintaining photo-electrical performance and extending the imaging member's service life.
Implementation Method 1
incorporating a plasticizer to relieve internal stress
Implementation Method 2
The charge transport layer should be able to transport the holes with as little trapping of charge as possible
Implementation Method 3
the charge generating layer should be capable of generating electron hole pair when exposed imagewise
Data Source
AI summary
Embodiments provide novel imaging members used in electrostatography. More particularly, there is provided flexible electrophotographic imaging members which have improved imaging layer(s) formulated to comprise of a plasticizer in a material matrix of a solid solution comprising a charge transporting compound and a film forming polymer binder which is a novel A-B diblock copolymer or a binary polymer blend of a novel A-B diblock copolymer and a bisphenol polycarbonate. The flexible imaging members thus prepared have improved photoelectrical cyclic function stability, chemical resistive property, and are curl-free, and thus eliminate the need for an additional anticurl back coating layer.