Printhead Priming Detection via Movable Member Response Time

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Solution Overview

Problem

Existing methods for priming inkjet printheads, such as using gas pumps or pressure sensors, are often inefficient, costly, and ineffective, leading to difficulties in ensuring the printhead is properly primed before printing, which can result in inadequate ink supply and delayed printing processes.

Innovation Solution

A system that identifies primed printheads by moving a movable member from a first position to a second position to cause ink flow and measures the response time, estimating pressure along the ink flow path, allowing for efficient and flexible priming without the need for costly pressure sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas pumps or pressure sensors are used to prime printheads, then priming function is achieved, but system cost and complexity increase

Engineering Contradiction:
Improvepriming functionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the pressure sensor from the system and extracts only the essential priming function. Instead of using complex pressure sensing and control mechanisms, the invention uses a simple movable member that blocks the ink flow path to achieve priming through ink pressure buildup alone, eliminating unnecessary components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The printhead system primes itself using its own ink supply pressure. The movable member simply blocks the flow path, allowing ink pressure to naturally build up and prime the system without requiring external gas pumps or active pressure control mechanisms. The system uses its inherent properties to achieve priming.

Inventive Principle:
Principle #25Self-service

2Reliability

If gas pumps are used to prime printheads, then priming function is achieved, but operation time and efficiency increase

Engineering Contradiction:
Improvepriming functionVSAvoidpriming time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent skips the complex multi-step priming process used by gas pump systems. By simply blocking the ink flow path with the movable member, the system rapidly builds up ink pressure and achieves priming in a single straightforward action, significantly reducing priming time compared to gradual gas pressure buildup methods.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Measurement precision

If pressure sensors are used to detect priming status, then accurate detection is achieved, but device cost and space increase

Engineering Contradiction:
Improvepriming detection accuracyVSAvoidcomponent count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the electronic pressure sensing system with a simple mechanical indicator. The movable member's position itself indicates priming status - when it moves to block the flow path, priming is achieved. This mechanical indication eliminates the need for electronic sensors, signal processing, and associated complexity while maintaining detection functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If gas pumps are used to prime printheads, then priming function is achieved, but energy consumption increases

Engineering Contradiction:
Improvepriming functionVSAvoidpriming energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent converts the potentially harmful effect of uncontrolled ink pressure into a beneficial priming mechanism. By blocking the flow path, the natural ink pressure builds up to the exact level needed for priming, transforming what could be a pressure control problem into a self-regulating priming solution that consumes minimal energy.

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

This approach enables efficient and flexible priming of printheads, ensuring the printhead is properly primed by estimating pressure based on response time, reducing unnecessary operation and space-intensive components, and accommodating real-world variations in printhead priming.

Implementation Method 1

moving a movable member of a printhead from a first position to a second position to cause ink to flow from an ink supply into the printhead

Methodology Applied
Scientific EffectFluid pressure: Pressure Gradient

Implementation Method 2

cause ink to flow from an ink supply into the printhead to prime the printhead

Methodology Applied
Scientific EffectFluid flow: Hydraulic Press

Data Source

PatentEP3250392B1Identifying primed printheads
Publication Date: 2022.03.02 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3250392B1 patent drawingFigure 1
  • EP3250392B1 patent drawingFigure 2
  • EP3250392B1 patent drawingFigure 3

AI summary

Priming printheads can, in various examples, include moving a movable member of a printhead from a first position to a second position, measuring a response time of the movable member to move from the first position to the second position, and identifying the printhead as primed.