Ink Buildup Sensor Detecting Light Reduction in Continuous Ink Jet Print Heads

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Solution Overview

Problem

Ink buildup on surfaces adjacent to ink droplets in continuous ink jet printing systems can obstruct the flight path of ink droplets, leading to print quality issues and potential shutdowns, as existing systems lack effective detection and prevention mechanisms.

Innovation Solution

A sensor arrangement that detects ink buildup on internal surfaces of the print head by monitoring a reduction in sensed light, allowing for timely notification and automatic cleaning to prevent interference with print quality and EHT trips.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous ink jet printing operates for extended periods, then productivity increases, but ink accumulation on internal surfaces occurs which obstructs droplet flight paths and degrades print quality

Engineering Contradiction:
Improvecontinuous operation timeVSAvoidprint quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The optical sensor detects ink accumulation on internal surfaces before it becomes large enough to obstruct the droplet flight path. By performing detection in advance, the system can trigger cleaning operations proactively, preventing print quality degradation before it occurs and enabling continuous high-productivity operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The optical sensor continuously monitors the internal surfaces for ink accumulation and provides feedback to the control system. When accumulation exceeds a threshold, the system automatically initiates cleaning operations, creating a closed-loop control that maintains print quality while enabling continuous operation.

Inventive Principle:
Principle #23Feedback

2Device complexity

If ink buildup is detected late, then detection simplicity is maintained, but droplet flight paths become obstructed causing shutdowns

Engineering Contradiction:
Improvedetection systemVSAvoidprinting continuity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

An optical sensor acts as an intermediary detection mechanism that monitors ink accumulation on internal surfaces indirectly by measuring light transmission. This simple optical approach detects buildup early before it affects droplet flight paths, maintaining both detection simplicity and printing continuity through automatic cleaning triggers.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If no detection mechanism is used, then device complexity remains low, but ink accumulation leads to EHT trips and process shutdowns

Engineering Contradiction:
Improvesensor arrangementVSAvoidprocess stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces complex mechanical detection mechanisms with a simple optical sensor system that measures light transmission through the gutter. This substitution maintains low device complexity while providing reliable detection of ink accumulation that could cause EHT trips or shutdowns, thereby improving process stability.

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

The sensor arrangement effectively detects ink accumulation before it affects print quality, enabling proactive maintenance and preventing shutdowns by automatically cleaning the buildup, thus ensuring continuous operation and maintaining print quality.

Implementation Method 1

An ink buildup sensor is configured to detect an accumulation of ink on a print head surface via a change in an amount of light sensed by the ink buildup sensor

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3152058B1An ink buildup sensor arrangement
Publication Date: 2018.12.19 VIDEOJET TECH INC
  • EP3152058B1 patent drawingFigure 1
  • EP3152058B1 patent drawingFigure 2
  • EP3152058B1 patent drawingFigure 3~6

AI summary

A continuous ink jet print head (10), including: an ink droplet generator (116) configured to emit an ink droplet (158) along an undeflected droplet flight path (30); a charge electrode (118) configured to impart a charge to the ink droplet; deflector plates (120A, 120B) adjacent the undeflected droplet flight path, downstream from the charge electrode, and configured to deflect the ink droplet to a deflected droplet flight path that lies within a range of deflected flight paths bounded by at least deflected droplet flight path and a most deflected droplet flight path; a gutter (122) configured to receive an ink droplet traveling along the undeflected droplet flight path; and an ink buildup sensor (102) configured to detect an accumulation of ink (140) relative to a droplet flight path disposed within the range of deflected flight paths.