Printhead Position Verification via Drop Detection

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Solution Overview

Problem

The manual reconfiguration of printheads in print apparatuses for different printing modes is prone to user error, leading to incorrect positioning and resulting in wasted substrate and printing fluid.

Innovation Solution

A method utilizing a drop detector to determine the position of printheads by ejecting a drop of printing fluid into a detection zone and analyzing its presence and location, thereby confirming the correct positioning of printheads for different print modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual reconfiguration of printheads is performed, then adaptability to different printing modes is improved, but reliability of correct positioning deteriorates due to user error

Engineering Contradiction:

Improveadaptability to different printing modesVSAvoidreliability of correct positioning

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system provides automatic feedback by detecting the actual position of printheads using a drop detector and comparing it with the expected position for the selected printing mode. This feedback mechanism eliminates user error by automatically verifying and indicating whether printheads are correctly positioned, thus maintaining high reliability while supporting adaptability to different printing modes.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-verification of printhead positioning by automatically ejecting a test drop and detecting its position. This self-service capability allows the system to autonomously confirm correct configuration without requiring manual verification, thereby maintaining reliability while enabling easy adaptation to different printing modes.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If manual reconfiguration of printheads is performed, then adaptability to different printing modes is improved, but loss of substrate and printing fluid increases due to incorrect positioning

Engineering Contradiction:

Improveadaptability to different printing modesVSAvoidloss of substrate and printing fluid

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The system performs a preliminary position verification by ejecting a test drop and detecting its position before actual printing begins. This preliminary action identifies any mispositioning of printheads early, allowing correction before substantial substrate and printing fluid are consumed, thus reducing waste while maintaining adaptability to different printing modes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system provides immediate feedback on printhead positioning accuracy through visual or audible indications. This feedback enables operators to correct positioning errors before proceeding with full printing operations, thereby preventing waste of substrate and printing fluid while preserving the ability to adapt to different printing modes.

Inventive Principle:

Principle #23Feedback

3Reliability

If automatic drop detection is implemented, then reliability of printhead positioning is improved, but device complexity increases

Engineering Contradiction:

Improvereliability of printhead positioningVSAvoidcomplexity of detection system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses a simple optical intermediary (light source and sensor) to detect the position of printhead drops. This intermediary approach provides reliable detection without requiring complex mechanical or electronic positioning systems, thus achieving high reliability while minimizing the increase in device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces complex mechanical positioning verification mechanisms with an optical detection method. By using light-based drop detection instead of mechanical sensors or complex measurement systems, the patent achieves reliable printhead positioning verification while keeping the added complexity minimal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method reduces user error in reconfiguring printheads, ensuring accurate positioning and minimizing waste by providing a visual or audible indication of correct printhead alignment before starting a print operation.

Implementation Method 1

A method is described herein of utilizing a drop detector to determine a position of a printhead by controlling a predetermined nozzle of the printhead to eject a drop of printing fluid into a drop detection zone of the print apparatus and determining, from a detection of the drop within the drop detection zone, an indication of the position of the printhead

Methodology Applied

Scientific EffectOptical detection: Absorption (EM radiation)

Data Source

PatentEP4337472B1Printhead positions

Publication Date: 2025.06.18 HEWLETT PACKARD DEVELOPMENT COMPANY LP

Figure 1~3A
Figure 3B~4
Figure 5

AI summary

In an example, a method includes ejecting a drop of printing fluid from a nozzle of a printhead into a drop detection zone. An indication of detection of the drop within the drop detection zone may be determined and, based on the indication of detection of the drop, an indication of a position of the printhead may be provided.