Inkjet Print Head Maintenance Unit Performance Monitoring

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Solution Overview

Problem

Inkjet printing systems lack effective control over maintenance units, leading to inaccurate droplet ejection and premature failure of print heads due to undetected maintenance unit performance issues.

Innovation Solution

A method to determine maintenance unit performance by detecting and analyzing pressure waves generated in the ink chambers during maintenance operations, which are influenced by the presence and properties of the wiper element or ink over the orifice surface, allowing for real-time monitoring and assessment of maintenance effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If maintenance unit operates without control, then device complexity is reduced, but reliability deteriorates due to undetected performance issues

Engineering Contradiction:

Improvemaintenance unit control systemVSAvoidmaintenance unit performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The maintenance unit performs self-diagnosis by generating and detecting pressure waves during its own operation. The wiper element itself creates the pressure waves when it contacts the orifice surface, eliminating the need for separate external testing equipment or complex control systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses feedback by detecting the pressure waves generated during maintenance operation and analyzing them to determine the performance status of the wiper element. This real-time feedback allows the system to monitor maintenance effectiveness without adding complex external control mechanisms.

Inventive Principle:

Principle #23Feedback

2Device complexity

If maintenance unit performance is not monitored, then device complexity is reduced, but manufacturing precision deteriorates due to inaccurate droplet ejection

Engineering Contradiction:

Improveperformance monitoring systemVSAvoiddroplet ejection accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The system continuously monitors maintenance unit performance by detecting pressure waves during operation and uses this feedback to ensure the wiper element is properly cleaning the orifice surface, thereby maintaining droplet ejection accuracy without requiring complex monitoring systems.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical or optical monitoring systems with an acoustic field-based detection method. By using pressure waves in the ink chamber, the system can monitor maintenance performance through acoustic signals rather than complex mechanical sensors or optical systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If print head is replaced instead of servicing maintenance unit, then reliability is improved temporarily, but loss of time increases due to premature replacement cycles

Engineering Contradiction:

Improveprint head functionalityVSAvoidreplacement cycle time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system provides real-time feedback on maintenance unit performance, allowing operators to detect when the wiper element is failing and schedule timely servicing. This prevents premature print head failures and eliminates the need for frequent replacements, reducing overall downtime.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system enables preliminary detection of maintenance unit degradation before it causes print head failure. By monitoring pressure waves during maintenance operations, the system can identify deteriorating performance early and schedule servicing before the print head is affected, preventing premature replacement.

Inventive Principle:

Principle #10Preliminary 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

Enables early detection of failing maintenance units, preventing print quality deterioration and reducing unnecessary print head replacements by accurately assessing maintenance unit performance and ensuring proper operation.

Implementation Method 1

a pressure wave may be generated in the ink chambers of the print head upon performing the maintenance operation, which pressure wave is dependent on the performance of the maintenance unit

Methodology Applied

Scientific EffectPressure wave: Sound

Implementation Method 2

In order to determine whether a wiper element is present over an orifice, or whether an amount of ink is present over the orifice, a pressure wave may be generated in the ink chamber

Methodology Applied

Scientific EffectPressure wave generation: Sound

Data Source

PatentUS8882239B2Method for determining maintenance unit performance

Publication Date: 2014.11.11 CANON PRODUCTION PRINTING NETHERLANDS BV

AI summary

In a method for determining a maintenance performance of a maintenance unit of an inkjet printing system, the inkjet system comprises an inkjet print head having an orifice surface, the orifice surface comprising an orifice, which orifice is in fluid communication with an ink chamber. The method comprises operating the maintenance unit to perform a maintenance operation on the orifice surface of the inkjet print head and detecting the presence of a wiper element or amount of ink over the orifice by detecting a pressure wave in the ink chamber and analyzing the detected pressure wave to determine the maintenance performance of the maintenance unit.