Inkjet Head Module Replacement Maintenance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In ink jet printers, especially line ink jet heads composed of multiple modules, nozzle clogging and air bubble incorporation occur during head module replacement due to exposure and vibration, leading to instability in performance.

Innovation Solution

A maintenance method involving a liquid circulation and supply system that keeps non-replacement head modules moisturized and controls back pressure to prevent clogging and air bubble incorporation during module replacement, using a system with a tank, manifold, valves, and bypass paths to ensure continuous ink flow and air bubble removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If head module replacement is performed with nozzle surfaces exposed, then replacement operation is enabled, but nozzle clogging occurs due to drying

Engineering Contradiction:

Improvehead module replacementVSAvoidnozzle function

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A cap is introduced as an intermediary component to cover the nozzle surfaces during head module replacement operations. The cap prevents direct exposure of the nozzles to air, thereby preventing ink drying and clogging while allowing the replacement operation to proceed. This mediator protects the vulnerable nozzles without interfering with the replacement process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cap is placed on the nozzle surfaces before the head module replacement begins, and remains in place throughout the replacement process. This preliminary protective action ensures that the nozzles are already protected when vibration occurs during replacement, preventing both drying and potential contamination before they can cause damage.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If head module replacement is performed with nozzle surfaces covered by cap, then nozzle drying is prevented, but vibration causes ink overflow or air bubble incorporation

Engineering Contradiction:

Improvenozzle functionVSAvoidink overflow and air bubble incorporation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the ejection state of the head module during replacement operations. By controlling the ejection mechanism to maintain a specific pressure state, the system adapts to the changing conditions during replacement, preventing ink overflow and air bubble incorporation while the cap is in place.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The ejection pressure parameter is changed during head module replacement to prevent harmful effects. By adjusting the pressure parameter, the system prevents ink from overflowing due to vibration while the cap is covering the nozzles, and also prevents air bubbles from being incorporated into the ink supply system.

Inventive Principle:

Principle #35Parameter changes

3Speed

If multiple head modules are joined to form long line ink jet head, then high-speed recording is enabled, but cumulative pitch error increases in processing

Engineering Contradiction:

Improverecording speedVSAvoidpitch accuracy

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The line ink jet head is segmented into multiple replaceable head modules, each with a manageable number of nozzles. This segmentation allows each module to be manufactured with high precision while enabling the formation of a long recording head by joining multiple modules. The modular structure reduces cumulative pitch errors compared to a single long head.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system provides self-service functionality by enabling easy replacement of individual head modules. When a module needs maintenance or replacement, it can be independently swapped without affecting other modules, ensuring continuous high-precision operation and maintaining overall system accuracy.

Inventive Principle:

Principle #25Self-service

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 method maintains stable performance by preventing nozzle clogging and air bubble incorporation during head module replacement, ensuring continuous operation without performance degradation.

Implementation Method 1

a liquid circulation and supply unit configured to circulate and supply liquid to be ejected from each head modules, to each head module

Methodology Applied

Scientific EffectFluid circulation: Convection

Implementation Method 2

in a case of circulating and supplying the liquid while controlling a value of back pressure of the liquid in the head module to a predetermined value

Methodology Applied

Scientific EffectBack pressure control: Pressure Gradient

Data Source

PatentUS9102163B2Droplet ejection apparatus and maintenance method thereof

Publication Date: 2015.08.11 FUJIFILM CORP

AI summary

A maintenance method of a droplet ejection apparatus is provided, which droplet ejection apparatus includes: a droplet ejection head including a plurality of head modules, each head module being configured to be replaced independently; and a liquid circulation and supply unit configured to circulate and supply liquid to be ejected from each head module, to each head module. The maintenance method includes circulating and supplying the liquid to the head modules other than the head module that is a replacement target, when replacing the head module.