Printhead Electrode Charge Control for Particle Management

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Solution Overview

Problem

Particle collection on printheads in printing devices leads to degraded print quality, increased maintenance frequency, and higher operational costs due to electrostatic charge differences, causing end-user dissatisfaction and inefficiency.

Innovation Solution

A printhead assembly design featuring electrodes of opposing polarities to attract and collect particles, ensuring effective servicing and maintaining print quality by repelling particles during maintenance, thus preventing their accumulation and improving device reliability and speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If particles are allowed to collect on printheads during printing operations, then the printhead surface area increases over time, but print quality degrades and maintenance frequency increases

Engineering Contradiction:
Improveparticle accumulationVSAvoidprint quality
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies electrostatic charging to the printhead surface to convert the harmful effect of particle accumulation into a beneficial effect. By charging the printhead, particles are electrostatically attracted to the surface during printing, but then repelled during maintenance modes, enabling automatic particle removal and maintaining print quality without manual intervention

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

2Ease of repair

If traditional printhead maintenance methods are used without electrostatic control, then servicing can be performed, but particles remain difficult to remove due to electrostatic charge differences

Engineering Contradiction:
Improveparticle removalVSAvoidmaintenance effectiveness
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The patent implements dynamic electrostatic charging where the printhead surface charge is actively controlled and changed between printing and maintenance modes. During printing, the surface is charged to attract particles; during maintenance, the charge is reversed or discharged to repel particles, making them easy to remove with a wiper or airflow

Inventive Principle:
Principle #15Dynamics

3Reliability

If printhead servicing frequency is increased to maintain print quality, then print quality is preserved, but print job speed decreases due to more frequent interruptions

Engineering Contradiction:
Improveprint qualityVSAvoidprint job speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent enables the printhead to perform self-maintenance through electrostatic particle repulsion during maintenance modes. The charged surface automatically repels accumulated particles, and a simple wiper or airflow removes them without requiring frequent manual servicing, thus maintaining print quality while minimizing interruptions to print jobs

Inventive Principle:
Principle #25Self-service

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 maintains print quality, reduces maintenance frequency, and enhances print job speed, addressing the issues of particle collection and electrostatic interference, thereby improving user satisfaction and operational efficiency.

Implementation Method 1

an electrode to provide an electrostatic charge to attract and collect particles

Methodology Applied
Scientific EffectElectrostatic charge: Electrostatics

Implementation Method 2

attract and collect particles... by repelling particles during maintenance

Methodology Applied
Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Data Source

PatentEP3157752B1Printhead assembly
Publication Date: 2021.06.23 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3157752B1 patent drawingFigure 1
  • EP3157752B1 patent drawingFigure 2~3
  • EP3157752B1 patent drawingFigure 4~5

AI summary

Examples of a printhead assembly are disclosed herein. An example of the printhead assembly includes a die to print, a base member, and at least one electrode. The electrode may be used to provide a charge to attract and collect particles that would normally otherwise interfere with operation of the die.