Inkjet Printer Supply System with Recirculation Control

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Solution Overview

Problem

Inkjet printers using inks with high solids content face issues of sedimentation, which alter physical-chemical properties and cause clogging of print head nozzles, and existing supply systems fail to maintain consistent operation and independence from recirculation systems.

Innovation Solution

A supply system with a recirculation line and control mechanisms to maintain constant ink flow and pressure, independent of individual print head operations, using a distribution tube with a larger diameter to minimize head loss and incorporating sensors and pumps for pressure regulation and ink circulation, along with a safety circuit to prevent ink discharge during power failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If inkjet printers use inks with high solids content, then printing quality is improved, but sedimentation occurs causing nozzle clogging

Engineering Contradiction:
Improveprinting qualityVSAvoidnozzle clogging
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements a recirculation system that continuously circulates ink through the print heads even when not printing, maintaining constant fluid motion to prevent sedimentation. The system includes a circulation pump and reservoir that keeps ink in continuous movement, ensuring solids remain suspended and nozzles remain clear during idle periods

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent employs periodic flushing cycles where ink is pumped through the nozzles at regular intervals to prevent clogging. The system automatically initiates circulation sequences that move ink through the print heads periodically, maintaining nozzle patency without requiring continuous printing operation

Inventive Principle:
Principle #19Periodic action

2Adaptability or versatility

If print heads are individually supplied from ink reservoir, then printing flexibility is improved, but pressure imbalances occur affecting regular operation

Engineering Contradiction:
Improveprinting flexibilityVSAvoidpressure stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the ink supply system into separate independent lines: a supply-distribution line for delivering ink to print heads and a recirculation line for maintaining circulation. This segmentation allows each line to be optimized independently - the supply line provides flexibility while the recirculation line ensures pressure stability through continuous flow

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a reservoir as an intermediary component that decouples the supply-distribution system from the recirculation system. The reservoir acts as a buffer that maintains pressure stability while allowing flexible distribution to multiple print heads, absorbing pressure variations and preventing imbalances

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If recirculation system operates continuously, then sedimentation is prevented, but energy consumption increases

Engineering Contradiction:
Improvesedimentation preventionVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic circulation cycles instead of continuous operation. The system activates the circulation pump at scheduled intervals to move ink through the print heads and reservoir, preventing sedimentation while allowing energy-saving idle periods between circulation events

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses circulation flow rates that exceed the minimum required for sedimentation prevention during active cycles, ensuring thorough mixing and suspension of solids. The system applies excessive circulation temporarily during periodic cycles to guarantee reliability, then reduces to idle state, balancing energy use with effectiveness

Inventive Principle:
Principle #16Partial or excessive 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

The system effectively reduces sedimentation risks by maintaining constant ink movement and pressure stability, ensuring consistent operation even during temporary system shutdowns and allowing for independent head operation, reducing clogging and improving print quality.

Implementation Method 1

a first means for producing the circulation of the ink in the supply-distribution line (3)

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

At least the distribution tube (31) is shaped and proportioned so as to reduce to a minimum head loss of the liquid circulating therein

Methodology Applied
Scientific EffectHead loss reduction: Pressure Drop

Implementation Method 3

These means comprise a first pressure sensor (34) suitable for measuring the pressure existing in the distribution tube (31)

Methodology Applied
Scientific EffectPressure sensing:

Implementation Method 4

The apparatus (50) keeps the reservoir (5) under vacuum conditions, creating therein the said preset vacuum value

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 5

The latter provides for replenishment of the liquid until the pre-established level is reached

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 6

a suction-pumping device, which is preferably constituted by a pump (43) that is commanded to suction the ink from the collection manifold (41) and re-introduce it into the reservoir (5)

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 7

a pressure sensor (42) provided for measuring the pressure existing in the recirculation line (4)

Methodology Applied
Scientific EffectPressure sensing:

Data Source

PatentEP2834073B1Supply system for inkjet printers
Publication Date: 2015.10.21 SYST SPA
  • EP2834073B1 patent drawingFigure 1
  • EP2834073B1 patent drawingFigure 2~3
  • EP2834073B1 patent drawingFigure 4

AI summary

A supply system for an Inkjet printer of a type comprising at least one printing unit made up of one or more printing heads (1) with ink recirculation, each of which is equipped with one or more nozzles (11) for at least one colour. The system comprises: - a line for supply-distribution (3) of the ink and that originates from a reservoir (5), has a plurality of short connecting branches (30) for supplying the said print heads (1) and empties into the same reservoir (5); - a line for recirculation (4) of the ink and made up of a plurality of short channels (40) originating from the said print heads (1) and converging into a collection manifold (41), which empties into the said reservoir (5). First and second means provide for producing the circulation of the ink, in the supply-distribution line (3) and in the recirculation line (4) comprising the collection manifold (41), respectively. A control means is provided to control the pressure in the supply- distribution line (3) and particularly in the distribution tube (31). An additional control means controls the pressure and circulation in the recirculation line (4) comprising the said collection manifold (41).