Ink Drop Backscatter Detection for Nozzle Reliability

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Solution Overview

Problem

Inkjet printing devices face challenges in detecting nozzle issues, particularly in single-pass print modes where nozzles are frequently used, leading to potential clogging and reduced print quality due to the inability to assess nozzle functionality effectively.

Innovation Solution

A drop-detection system utilizing a radiation source and sensor, combined with a controller, performs backscatter drop-detection techniques to assess nozzle functionality by illuminating and monitoring light reflected from ink drops, including calibration methods for nozzle positioning and pigment separation to enhance detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If single-pass print mode is used to increase productivity, then printing speed is improved, but nozzle clogging occurs more frequently due to continuous operation without assessment

Engineering Contradiction:
Improveprinting speedVSAvoidnozzle functionality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary drop detection assessment of nozzle functionality before and during printing operations. By continuously monitoring drop characteristics (presence, size, shape, color) using optical sensors, the system identifies clogged or malfunctioning nozzles before they cause print quality degradation, enabling preventive maintenance in single-pass mode

Inventive Principle:
Principle #10Preliminary action

2Productivity

If continuous printing operation is performed to maintain productivity, then output is improved, but detection of nozzle issues becomes difficult without interrupting operation

Engineering Contradiction:
Improvecontinuous outputVSAvoidnozzle issue detection
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The system implements continuous drop detection monitoring during printing operations without interrupting the printing process. Optical sensors continuously assess ejected drops to detect nozzle abnormalities in real-time, maintaining both high productivity and reliable nozzle monitoring through uninterrupted observation of drop characteristics

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If optical detection methods are used to monitor ink drops, then measurement capability is improved, but noise interference from backscatter and electrical sources increases

Engineering Contradiction:
Improvedrop detection accuracyVSAvoidnoise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses optical sensors as intermediaries to detect ink drop characteristics indirectly through light interaction. By measuring light absorption, reflection, and scattering properties of ejected drops, the system obtains precise nozzle functionality data while the optical mediation naturally filters out electrical noise and reduces the impact of direct backscatter interference

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The system effectively determines nozzle health, reduces noise interference, and improves print quality by accurately detecting the presence and characteristics of ink drops, enabling timely maintenance and substitution of malfunctioning nozzles.

Implementation Method 1

a radiation sensor to detect radiation from the radiation source that is reflected by backscattering from drops

Methodology Applied
Scientific EffectBackscattering: Scattering

Data Source

PatentEP2900475B1Drop detection
Publication Date: 2018.03.28 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2900475B1 patent drawingFigure 1A~1B
  • EP2900475B1 patent drawingFigure 2
  • EP2900475B1 patent drawingFigure 3

AI summary

A system for drop detection of fluid drops ejected by a printing device includes a drop detector comprising a radiation source and radiation sensor for illuminating a region in which drops are ejected by a print bar and detecting radiation from the radiation source that is reflected by backscattering from the drops to the radiation sensor; and a controller for controlling the drop detector and the print bar, wherein the controller uses a signal output by the drop detector to determine whether nozzles of the print bar are operating properly.