Squeegee Roller Braking Mechanism for Liquid Electro-Photography Printers

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Solution Overview

Problem

Liquid electro-photography printing devices face print quality issues due to ineffective cleaning and anomalies such as streaks caused by air bubbles in the ink on the developer roller, which can lead to non-uniform ink transfer and image defects.

Innovation Solution

Implementing a squeegee roller braking mechanism that stops the squeegee roller from rotating relative to the developer roller during specific phases of operation, allowing the ink to act as a lubricant and reducing friction, while also using a sponge roller and squeezer roller to recover and reuse excess ink, and a processor to control the operation of rollers and voltages for effective cleaning and ink development.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the squeegee roller continues rotating in reverse during cleaning phase, then drip line removal is effective, but streaks and anomalies occur due to air bubbles in the ink on the developer roller

Engineering Contradiction:
Improvedrip line removal effectivenessVSAvoidimage quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The squeegee roller operates in periodic cycles: rotating in reverse during the cleaning phase to remove drip lines, then stopping and rotating forward during the printing phase to apply ink uniformly. This periodic reversal of rotation direction allows the system to alternately perform drip line removal and uniform ink application, resolving the contradiction between effective cleaning and preventing streaks.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The squeegee roller performs drip line removal during the cleaning phase before the printing phase begins. By removing drip lines in advance, the system prevents potential image defects from occurring during subsequent printing operations, ensuring high image quality without compromising cleaning effectiveness.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the squeegee roller stops rotating during operation, then uniform ink layer is achieved, but cleaning effectiveness may be reduced

Engineering Contradiction:
Improveink layer uniformityVSAvoidcleaning effectiveness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The squeegee roller alternates between stopping (during printing phase to ensure uniform ink layer) and rotating in reverse (during cleaning phase to maintain cleaning effectiveness). This periodic operation allows both functions to be performed optimally at different times in the duty cycle.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The rotation state of the squeegee roller is dynamically adjusted based on the operational phase: stopped during printing to achieve uniform ink application, and rotating in reverse during cleaning to remove drip lines. This dynamic control allows the system to adapt to different operational requirements and resolve the contradiction between uniformity and cleaning effectiveness.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If cleaning is performed more aggressively, then image quality improves, but risk of causing anomalies such as streaks increases

Engineering Contradiction:
Improveimage qualityVSAvoidstreaks and anomalies
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The system performs aggressive drip line removal during the cleaning phase when no printing is occurring, then transitions to a gentle forward rotation during the printing phase to apply ink uniformly without creating streaks. This temporal separation allows aggressive cleaning without compromising image quality.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Drip line removal is performed in advance during the cleaning phase before printing begins. By removing potential sources of defects beforehand, the system can use gentle ink application during printing without risk of streaks, achieving both high image quality and avoidance of anomalies.

Inventive Principle:
Principle #10Preliminary action

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

This solution reduces or eliminates streaks and other anomalies, ensuring high-quality image transfer by maintaining a uniform ink layer and effective cleaning, thereby enhancing the overall print quality of liquid electro-photography printing devices.

Implementation Method 1

allowing the ink to act as a lubricant and reducing friction

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

Electro-photography printing forms an image on a substrate by selectively charging or discharging a photoconductive member with an image to be printed

Methodology Applied
Scientific EffectPhotoconductivity: Photoconductivity

Implementation Method 3

A LEP printing device comprises a binary ink developer (BID) that applies the ink to a developer roller (DR)

Methodology Applied
Scientific EffectElectrostatics: Electrostatics

Data Source

PatentEP3662327B1developers
Publication Date: 2023.08.16 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3662327B1 patent drawingFigure 1
  • EP3662327B1 patent drawingFigure 2
  • EP3662327B1 patent drawingFigure 3

AI summary

A developer for a printer for printing to a substrate; the developer comprising a plurality of rollers operable to influence forming an image; the plurality of rollers comprising a developer roller for bearing printing liquid for forming the image and a squeegee roller for cooperating with the developer roller to influence the printing liquid on the developer roller, the squeegee roller being operable, via a brake, to stop rotating relative to the developer roller to influence the printing liquid on the developer roller.