Reversible Ink Pump for Pigment Dispersion

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Solution Overview

Problem

Continuous inkjet printers using pigmented inks face issues with pigment settlement, leading to reduced print quality due to the ink becoming less opaque when pigment settles out, and existing solutions like mechanical stirrers or conical ink tanks are either costly or inefficient.

Innovation Solution

A continuous inkjet printer system with a reversible ink drive arrangement and multiple inlet openings at the bottom of the ink tank, allowing for reverse flow to disturb and mix settled pigment back into the ink, maintaining ink opacity without the need for additional components like magnetic stirrers or conical designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a mechanical stirrer is used to prevent pigment settlement, then pigment mixing is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepigment mixingVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The ink pump serves dual functions: it not only circulates ink through the system but also acts as a self-service mixing mechanism by creating reverse flow that agitates and remingles pigment in the ink tank, eliminating the need for a separate mechanical stirrer

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The ink pump is designed to perform multiple functions simultaneously: ink circulation, pressure regulation, and pigment mixing through reverse flow capability, thereby consolidating what would traditionally require separate components

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

2Stability of the object's composition

If a conical funnel-shaped bottom ink tank is used to gather settled pigment, then pigment collection is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepigment gatheringVSAvoidease of manufacture
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Instead of using a conical shape to passively gather pigment at the bottom, the invention inverts the approach by using the pump to actively create reverse flow that lifts pigment from the bottom back into circulation, achieving mixing without special tank geometry

Inventive Principle:
Principle #13The other way round (Inversion)

3Stability of the object's composition

If the pump runs continuously to mix pigment, then pigment suspension is improved, but energy consumption increases

Engineering Contradiction:
Improvepigment suspensionVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The pump operates periodically rather than continuously, running at high speed to create reverse flow for a set duration to suspend pigment, then slowing or stopping, thereby achieving effective pigment mixing while minimizing energy consumption compared to continuous operation

Inventive Principle:
Principle #19Periodic 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 prevents pigment settlement by ensuring continuous mixing and agitation, maintaining ink opacity and print quality without increasing costs or complexity.

Implementation Method 1

the ink pump being operable to drive fluid around the ink circuit in a reverse direction such that fluid flows from the ink pump along the ink supply path and out through the ink entrance openings

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP3694721B1Pigment dispersal in an ink jet printer
Publication Date: 2024.11.20 LINX PRINTING TECH
  • EP3694721B1 patent drawingFigure 1~3
  • EP3694721B1 patent drawingFigure 4
  • EP3694721B1 patent drawingFigure 5

AI summary

In a continuous ink jet printer for use with pigmented ink, the entrance to the ink path (81), (35) from the interior of the ink tank (27) to the ink pump (31) is made up of a plurality of small inlet openings, which may be provided by nozzles 85 formed in a shroud 83 that fits around an ink filter (33) in the ink tank (27). The openings are provided at the bottom of the ink tank (27), close to the floor, and face parallel to the floor or at least partially towards it. If the ink pump (31) is driven in reverse, any ink in the ink path is driven at speed out through the inlet openings into the interior of the ink tank (27), followed by air. This tends to disperse pigment that may have settled to the bottom on the ink tank (27).