Semi-crystalline Polyester Interfacial Layer for Photoreceptor Plywood Effect

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Solution Overview

Problem

The 'plywood effect' or interference fringe effect in electrophotographic printing, caused by coherent illumination and multilayered photoreceptors, results in print quality defects due to light interference, and existing solutions are either costly or inefficient.

Innovation Solution

An imaging member with an interfacial layer comprising a semi-crystalline polyester resin, which significantly reduces light interference by blocking light transmission from the charge generation layer to the metal substrate, maintaining excellent electrical properties and preventing the 'plywood effect' without requiring significant process modifications or additional costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multilayered photoreceptor structure is used, then charge transport performance is improved, but light interference (plywood effect) occurs due to coherent illumination

Engineering Contradiction:

Improvecharge transport performanceVSAvoidlight interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An interfacial layer is introduced between the charge blocking layer and the charge generation layer to act as an intermediary that suppresses light reflection. This layer has a refractive index intermediate between the charge blocking layer and the charge generation layer, reducing optical interference while preserving the multilayered structure's charge transport benefits

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index parameter of the interfacial layer is specifically optimized to be intermediate between the charge blocking layer and charge generation layer. This parameter change effectively reduces light reflection and plywood effect while maintaining electrical performance

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional interfacial layers are used, then manufacturing cost is low, but light transmission causes plywood effect

Engineering Contradiction:

Improvemanufacturing costVSAvoidplywood effect

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The interfacial layer is formed from a composite material system where the resin matrix is selected to provide the appropriate refractive index. This allows achieving optical interference suppression without requiring expensive specialized materials or complex manufacturing processes

Inventive Principle:

Principle #40Composite materials

3Reliability

If light transmission is increased to improve image formation, then charge generation efficiency is improved, but interference fringe effect worsens

Engineering Contradiction:

Improvecharge generation efficiencyVSAvoidinterference fringe effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The interfacial layer serves as an optical intermediary that reduces reflection at the charge blocking layer interface while allowing sufficient light transmission to reach the charge generation layer, thus maintaining charge generation efficiency without the plywood effect

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interfacial layer provides localized optical property modification at the critical interface region, affecting only the light reflection characteristics at that specific location while leaving the overall light transmission and charge generation processes unaffected

Inventive Principle:

Principle #3Local quality

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 use of a semi-crystalline polyester resin interfacial layer effectively eliminates the 'plywood effect' while preserving excellent electrical properties, achieving near zero light transmission in the visible range and stable cycling performance, thus improving print quality without increasing production costs.

Implementation Method 1

the interfacial layer comprises a semi-crystalline polyester resin to prevent light transmission to the substrate and thus significantly reduce 'plywood effect'

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

the reflected light from the undercoat layer (or charge blocking layer)/charge generating layer interface account for the interference fringe effect

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 3

the use of coherent illumination sources in conjunction with multilayered photoreceptors results in the 'plywood effect,' also known as 'interference fringe effect'

Methodology Applied

Scientific EffectCoherent light: Coherent Light

Implementation Method 4

This defect consists of a series of dark and light interference patterns that occur when the coherent light is reflected from the interfaces that pervade multilayered photoreceptors

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS8273512B2Photoreceptor interfacial layer

Publication Date: 2012.09.25 XEROX CORP

AI summary

The presently disclosed embodiments relate generally to layers that are useful in imaging apparatus members and components, for use in electrostatographic, including digital, apparatuses. Embodiments pertain to an improved electrostatographic imaging member comprising an interfacial layer further comprising an opaque semi-crystalline polyester resin that is also a hot-melt adhesive to prevent light transmission to the substrate and thus significantly reduce “plywood effect,” a print quality defect.