Release Layer Carbon Black Dispersion ITM Memory

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Solution Overview

Problem

Previous intermediate transfer member (ITM) release layers in electrostatic printing systems suffer from negative dot gain memory and short-term memory issues, affecting image quality and consistency.

Innovation Solution

A pre-cure release layer composition comprising silicone oil, carbon black, and a trisiloxane surfactant is used to form a silicone polymer matrix, which improves the memory of the ITM by enhancing carbon black dispersion and increasing its amount in the outer release layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional release layer is used in the ITM, then the ITM can transfer charged particles from the photoconductive surface to the print substrate, but the release layer suffers from negative dot gain memory and short-term memory issues that degrade image quality

Engineering Contradiction:
Improveimage quality consistencyVSAvoidnegative dot gain memory and short-term memory
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters of the release layer by incorporating specific silicones (polydimethylsiloxane and/or polyalkyl siloxane) with controlled molecular weights and concentrations. This chemical parameter change eliminates the memory effects while preserving the release function, thereby improving image quality consistency without introducing new harmful factors

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite release layer material combining specific silicones with the base release layer composition. This composite structure maintains the necessary release properties for particle transfer while the silicone components specifically address and eliminate the negative dot gain memory and short-term memory issues, resolving the contradiction between reliability and harmful factors

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If the amount of carbon black in the release layer is increased to improve dispersion, then the memory effects are reduced, but the complexity of the release layer formulation increases

Engineering Contradiction:
Improvememory effectsVSAvoidrelease layer formulation complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent optimizes the carbon black concentration parameter within a specific range (0.1-5% by weight) and combines it with specific silicone additives. This parameter optimization achieves effective carbon black dispersion that reduces memory effects while avoiding excessive formulation complexity by establishing clear concentration boundaries and component specifications

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces negative dot gain and short-term memory, resulting in improved image quality with reduced ghosting effects in printed images, as demonstrated by reduced negative dot gain and short-term memory in printing tests.

Implementation Method 1

a trisiloxane surfactant is used to improve the dispersion of the carbon black in the silicone polymer matrix

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 2

The charged ink particles adhere to the image areas of the latent image while the background areas remain clean

Methodology Applied
Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentEP3414629B1Release layer
Publication Date: 2020.03.25 HP INDIGO BV
  • EP3414629B1 patent drawingFigure 1
  • EP3414629B1 patent drawingFigure 2
  • EP3414629B1 patent drawingFigure 3

AI summary

Herein is described a release layer comprising a silicone polymer matrix, carbon black and a trisiloxane surfactant.