Ink Supply System Pressure Uniformity via Common Intermediate Tank

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Solution Overview

Problem

High-performance inkjet printers with multiple nozzles require a precise and costly ink pressure supply system to ensure trouble-free operation, which is technically and economically challenging due to the need for a narrow pressure tolerance range.

Innovation Solution

An ink supply system that connects multiple printheads to a common intermediate tank via a line network with a distributor pipe, using flexible hoses for adjustable flow lengths and an inclined distribution pipe to ensure consistent pressure and prevent air bubbles, with a vacuum pump to prevent ink leakage and automated fill level monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple printheads are supplied with ink through individual pressure regulation systems to ensure narrow pressure tolerance, then printing reliability is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveprinting reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple individual pressure regulation systems into a single common pressure regulation system that supplies ink to multiple printheads simultaneously. This is achieved by introducing a common intermediate tank connected to all printheads through a line network, replacing the conventional approach of individual pressure regulators for each printhead. The single pressure regulation system maintains ink pressure within the required narrow tolerance range (±0.5 psi) for all printheads, ensuring printing reliability while significantly reducing device complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common intermediate tank serves multiple functions: it acts as a reservoir for ink supply, a pressure regulation point for the entire printhead array, and a reference level for ink pressure maintenance. By making this single component multi-functional, the system eliminates the need for separate pressure regulation mechanisms at each printhead, thereby reducing complexity while maintaining reliable operation across all print heads.

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

2Manufacturing precision

If individual pressure regulation components are used for each printhead to maintain narrow pressure tolerance, then ink pressure control is improved, but susceptibility to faults increases

Engineering Contradiction:
Improveink pressure controlVSAvoidsusceptibility to faults
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent combines multiple individual pressure regulation components into a single centralized pressure regulation system at the common intermediate tank. This reduction in the number of pressure-regulating components directly reduces the points of potential failure. The single regulation system maintains precise ink pressure control (within ±0.5 psi tolerance) for all printheads simultaneously, achieving both precise pressure control and reduced fault susceptibility.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If a common intermediate tank is used to supply ink to multiple printheads, then space required for ink supply components is reduced, but pressure uniformity across printheads must be maintained

Engineering Contradiction:
Improvespace requiredVSAvoidpressure uniformity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies the equipotentiality principle by designing the line network connecting the common intermediate tank to multiple printheads with carefully calculated flow resistance values. Each line section is dimensioned to compensate for distance variations, ensuring that the ink pressure at each printhead outlet is equalized despite different path lengths from the common tank. This creates a pressure-equipotential system where all printheads receive ink at the same pressure, maintaining manufacturing precision while utilizing space-efficient common supply architecture.

Inventive Principle:
Principle #12Equipotentiality

4Length of stationary object

If line sections are made long to connect distant printheads to the common tank, then system coverage is improved, but pressure loss increases

Engineering Contradiction:
Improvesystem coverageVSAvoidpressure loss
Core Design Contradiction:
Length of stationary objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by varying the flow resistance characteristics of different line sections based on their specific requirements. Line sections connecting distant printheads are designed with lower flow resistance to compensate for longer path lengths, while closer printheads have higher flow resistance. This localized adjustment of flow resistance in each line section ensures that all printheads, regardless of distance from the common intermediate tank, receive ink at the same pressure, thereby achieving extended system coverage without excessive pressure loss.

Inventive Principle:
Principle #3Local quality

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 design reduces the complexity and cost of the ink supply system, minimizes fault susceptibility, maintains consistent pressure across printheads, and allows for flexible adjustment of flow resistance, ensuring reliable operation with reduced risk of nozzle failure.

Implementation Method 1

the intermediate tank (12) is connected in such a way to a vacuum pump (16) that an undesired outflow of ink from the nozzles of the print heads (7) can be prevented

Methodology Applied
Scientific EffectNegative pressure: Vacuum

Implementation Method 2

the distribution pipe (20) is inclined at an angle (26) with respect to a horizontal plane... ensures that air bubbles in the ink can escape unhindered

Methodology Applied
Scientific EffectGravity-driven flow: Gravitation

Data Source

PatentEP2148782B1Ink supply system for an inkjet printer
Publication Date: 2011.10.26 DURST GROUP AG
  • EP2148782B1 patent drawingFigure 1

AI summary

The invention relates to an ink supply system (2) for an inkjet printer (1) having a print head arrangement (6) for at least one color, the print head arrangement (6) comprising a plurality of print heads (7) each having a plurality of nozzles and the print heads (7) being lined up to form a total print area width (10) corresponding to a multiple of a print area width (9) of a single print head (7). Each of the print heads (7) is connected via a line to an intermediate tank (12) for ink of the corresponding color, a plurality of print heads (7) being connected to a common intermediate tank (12).