Nozzle Ejection Trajectory Detection via Parallel Optical Sensing

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Solution Overview

Problem

Existing printer technologies face challenges in detecting and correcting vertical trajectory errors of ink droplets, which are time-consuming and costly, especially for large nozzle count printers, affecting print image quality.

Innovation Solution

A nozzle ejection trajectory detection system using a light source, lens, and sensor arrangement that allows for simultaneous detection of vertical trajectories from multiple nozzles in a single focal state, employing infrared light and a two-dimensional array of sensing elements to redirect and focus light, enabling efficient error detection and correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a beam scanning mechanism is used to detect droplet ejection trajectories, then detection capability is improved, but detection time and complexity increase significantly for large nozzle count printers

Engineering Contradiction:
Improvedroplet ejection trajectory detection capabilityVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The detection system divides the large nozzle array into multiple smaller detection zones, each handled by a dedicated detector. This segmentation allows parallel detection of multiple nozzle groups simultaneously, reducing total detection time while maintaining precision for each zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple detectors are combined to form a comprehensive detection system that covers the entire nozzle array. The detectors work in parallel to simultaneously monitor multiple ejection lines, transforming a sequential detection process into a parallel one that dramatically reduces detection time.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If individual refocusing is performed for each ejection line, then measurement precision is maintained, but device complexity and detection cost increase

Engineering Contradiction:
Improvetrajectory detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A single detector is designed to serve multiple ejection lines by detecting droplets across different spatial positions. The detector maintains measurement precision for all lines simultaneously through its positional resolution capability, eliminating the need for multiple specialized detectors or refocusing mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the detection parameter from sequential line-by-line analysis to simultaneous multi-position detection. By capturing droplet positions across multiple lines in a single detection event, the system maintains precision while reducing complexity and eliminating refocusing requirements.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If sequential detection of multiple nozzles is performed, then detection precision is maintained, but productivity decreases

Engineering Contradiction:
Improvevertical trajectory detection accuracyVSAvoiddetection throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The detection system operates continuously by having multiple detectors simultaneously monitor multiple ejection lines without interruption. This continuous parallel detection maintains measurement precision for each line while maximizing detection throughput, as all nozzles are monitored concurrently rather than sequentially.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs preliminary positioning and detection setup for all nozzles before actual detection begins. Once configured, all detectors operate simultaneously to detect trajectories across the entire array, enabling high-speed parallel detection that maintains precision while dramatically improving productivity.

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 system enables faster and less costly detection of vertical trajectory errors, allowing for enhanced print image quality by concurrently evaluating and correcting multiple nozzles without the need for refocusing, thus improving the overall efficiency of the printing process.

Implementation Method 1

light is reflected by the liquid droplets

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the reflected light from the liquid droplets is focused by a lens onto a detection plane

Methodology Applied
Scientific EffectLight focusing: Lens

Data Source

PatentEP2836366B1Nozzle ejection trajectory detection
Publication Date: 2019.10.23 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2836366B1 patent drawingFigure 1
  • EP2836366B1 patent drawingFigure 2~3
  • EP2836366B1 patent drawingFigure 4

AI summary

Light redirected by liquid droplets ejected from nozzles (30) of a plurality of columns (26, 226, 227) of nozzles (30) is sensed to detect a vertical trajectory of the liquid droplets for each of the nozzles (30).