Push-Primed Inkjet System Backpressure Control

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Solution Overview

Problem

Inkjet printers face issues with ink flow management due to inadequate backpressure control, leading to ink leakage or nozzle malfunction, and gas accumulation in the printhead, which restricts ink reception and delivery.

Innovation Solution

A push-primed inkjet printing system with an ink management system that includes a flexible air chamber and a regulator valve to control backpressure, using a pump to introduce gas and a check valve to block the vent, ensuring proper pressure regulation and air management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If backpressure is increased to prevent ink leakage, then ink flow control is improved, but nozzle firing may be restricted

Engineering Contradiction:
Improveink flow controlVSAvoidnozzle firing
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system dynamically adjusts backpressure levels based on operational needs. The pump selectively introduces gas to increase backpressure when ink leakage is detected, and releases gas when nozzle firing is restricted, allowing the system to adapt between preventing leakage and enabling proper nozzle operation.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If backpressure is decreased to improve nozzle firing, then nozzle operation is improved, but ink leakage may occur

Engineering Contradiction:
Improvenozzle firingVSAvoidink flow control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system monitors ink flow conditions and backpressure levels, using this feedback to control the pump operation. When ink leakage is detected, the system responds by introducing gas to increase backpressure. When nozzle firing is restricted, the system releases gas to decrease backpressure, creating a closed-loop control system.

Inventive Principle:
Principle #23Feedback

3Stress or pressure

If pump is used to introduce gas for pressure control, then pressure regulation is improved, but gas accumulation in printhead may occur

Engineering Contradiction:
Improvepressure controlVSAvoidgas accumulation
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The system extracts gas from the printhead by selectively introducing gas into the ink supply reservoir, which increases backpressure and forces accumulated gas out of the printhead and into the reservoir where it can be safely contained or vented.

Inventive Principle:
Principle #2Taking out (Extraction)

4Stress or pressure

If check valve is used to block vent during pressurization, then pressure control is improved, but ink flow restriction may occur

Engineering Contradiction:
Improvepressure controlVSAvoidink flow
Core Design Contradiction:
Stress or pressureVSEase of operation

Solution Approach 1:

The check valve dynamically transitions between open and closed states based on pressure differentials. During pressurization, the valve closes to maintain pressure control. During normal operation, the valve opens to allow ink flow, and during gas removal, the valve opens to allow gas to be forced into the reservoir.

Inventive Principle:
Principle #15Dynamics

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 system provides better pressure control, improved air management, enhanced print quality, longer printhead life, and more efficient ink use, with replaceable cartridges.

Implementation Method 1

The ink supply may be pressurized to prime the printhead. For example, a volume of gas may be introduced into the flexible chamber with a pump

Methodology Applied
Scientific EffectGas pressurization: Pressurisation

Implementation Method 2

Backpressure in the ink reservoir may be created by a backpressure mechanism including a flexible chamber (e.g., an air chamber of variable volume) and a biasing mechanism coupled to the flexible chamber

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP2010392B1Inkjet printing system with push priming
Publication Date: 2011.05.11 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2010392B1 patent drawingFigure 1~3
  • EP2010392B1 patent drawingFigure 4~8
  • EP2010392B1 patent drawingFigure 9~11

AI summary

An ink supply (24) for a push-primed inkjet printer (20) including an ink reservoir (52), a housing (56), and a pair of valves (66, 68). The housing (56) may enclose the ink reservoir (52) and define an opening (84) that provides fluid communication between the ink reservoir (52) and outside the housing (56). The pair of valves (66, 68) may be coupled to the housing (56), arranged in series, and configured to control the fluid communication.