Developer Roller End Sections Prevent Electrical Breakdown

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Solution Overview

Problem

In electrostatic printers, the non-electrically-conductive coating on developer rollers can retract from longitudinal ends, exposing them to electrodes and leading to electrical breakdown, melting, and gelation, which causes printing fluid splashing and inconsistencies.

Innovation Solution

The developer roller is designed with non-electrically-conductive sections at its longitudinal ends, which reduce the risk of arcing and subsequent melting or gelation, thereby maintaining print consistency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a non-electrically-conductive coating is applied on the surface of the developer roller to enhance printing fluid transfer, then printing fluid transfer is improved, but the coating retracts from longitudinal ends exposing the surface to the electrode, leading to electrical breakdown

Engineering Contradiction:

Improveprinting fluid transferVSAvoidelectrical breakdown risk

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The developer roller is divided into distinct sections: a central electrically-conductive section for printing fluid transfer and non-electrically-conductive sections (caps) at the longitudinal ends. This segmentation allows the roller to simultaneously achieve good printing fluid transfer in the central region while preventing electrical breakdown at the ends through the non-conductive caps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the developer roller are assigned different electrical conductivity properties. The central portion maintains electrically-conductive characteristics for optimal printing fluid transfer, while the longitudinal end portions are made non-electrically-conductive to prevent arcing with the electrode, thus applying local quality differentiation to resolve the contradiction.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the coating retracts from longitudinal ends, then the surface becomes exposed to the electrode, but this exposure causes arcing and subsequent melting and gelation of the developer roller

Engineering Contradiction:

Improvecoating applicationVSAvoidroller structural integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

Non-electrically-conductive sections are pre-installed at the longitudinal ends of the developer roller before the coating application process. This preliminary action ensures that even if the coating retracts during drying, the exposed end portions remain protected by the non-conductive sections, preventing arcing and maintaining structural integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The non-electrically-conductive sections at the longitudinal ends serve as a protective cushion against potential electrical breakdown. By placing these protective elements in advance at the vulnerable end portions, the design anticipates and prevents the harmful effects of coating retraction before they can cause melting or gelation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If electrical breakdown occurs between the exposed surface and electrode, then arcing happens, but this leads to melting and gelation causing printing fluid splashing and inconsistencies

Engineering Contradiction:

Improveelectrical breakdown preventionVSAvoidprinting fluid splashing

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention converts the potential harmful effect of coating retraction into a beneficial outcome by using the non-electrically-conductive sections to prevent electrical breakdown. What could have been a source of arcing and damage is instead utilized to protect the roller, transforming a potential harm into a protective mechanism that prevents printing fluid splashing and maintains process consistency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 non-electrically-conductive sections at the longitudinal ends of the developer roller effectively prevents electrical breakdown, reduces the risk of melting and gelation, and enhances print quality and consistency.

Implementation Method 1

a non-electrically-conductive section at each longitudinal end of the developer roller

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS12204260B2Developer roller

Publication Date: 2025.01.21 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

A developer roller having a first section that includes a first exterior surface, wherein the first exterior surface includes an electrically-conductive material; and a second section includes a second exterior surface, wherein the second exterior surface is non-electrically-conductive. The second section is axially aligned with the first section and provided at a first longitudinal end of the first section.