Automatic Tuning Compensation for Defective Printhead Nozzles

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Solution Overview

Problem

Current uniformity compensation methods for printhead nozzles in high-speed production printers require prior knowledge of ink spread and ink model simulation or manual tuning, which are time-consuming and inefficient, leading to undesired printing artifacts like voids and banding due to defective nozzles.

Innovation Solution

An automatic tuning mechanism for jet-out compensation using a compensation module that performs uniformity compensation by generating transfer and inverse transfer functions based on measurement data from a test chart, adjusting halftone threshold arrays to compensate for defective printhead nozzles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual tuning is performed to find optimal jet-out compensation strength, then compensation accuracy is improved, but time consumption increases

Engineering Contradiction:
Improvecompensation accuracyVSAvoidtuning time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs automatic tuning where the compensation module independently determines optimal jet-out compensation strength by analyzing measurement data from test charts, eliminating the need for manual operator intervention while maintaining high compensation accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary measurement and characterization of printhead nozzle defects using test charts before actual printing operations, establishing compensation parameters in advance to ensure uniformity compensation is ready when needed

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If ink model simulation is used to determine compensation parameters, then theoretical accuracy is improved, but complexity and time requirements increase

Engineering Contradiction:
Improvecompensation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex ink model simulation and theoretical calculations with direct empirical measurement using test charts and image analysis, substituting computational complexity with straightforward measurement and data processing

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes from using theoretical ink model parameters to using empirically measured parameters derived from actual test chart printing and image analysis, adapting to real-world variations in ink behavior and printhead performance

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If uniformity compensation is performed without automatic tuning, then manufacturing simplicity is maintained, but productivity decreases due to manual intervention

Engineering Contradiction:
Improvesystem simplicityVSAvoidcompensation speed
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The compensation module automatically performs all tuning operations independently, including measuring test charts, analyzing image data, and determining optimal compensation parameters, eliminating manual intervention while maintaining system simplicity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary automatic characterization of printhead defects and determination of compensation parameters before production printing begins, enabling rapid deployment without manual tuning during operations

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If manual tuning is required for jet-out compensation, then adaptability to specific printhead conditions is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecompensation adaptabilityVSAvoidoperator ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system automatically adapts to specific printhead conditions by independently measuring test charts, analyzing the actual jet-out patterns, and determining optimal compensation parameters tailored to that specific printhead without requiring operator expertise or manual adjustment

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4420882B1Automatic tuning compensation mechanism
Publication Date: 2025.10.22 RICOH CO LTD
  • EP4420882B1 patent drawingFigure 1
  • EP4420882B1 patent drawingFigure 2
  • EP4420882B1 patent drawingFigure 3A

AI summary

A printing system (130) includes at least one physical memory device (1425) to store compensation logic and one or more processors (1410) coupled with the at least one physical memory device to execute the compensation logic to receive measurement data corresponding to a print medium printed with a plurality of non-functioning pel forming elements, a plurality of functioning pel forming elements (165) and a plurality of tint levels; wherein adjacent ones of the plurality of functioning pel forming elements print with compensation transfer functions (230) applied and are located adjacent to the plurality of non-functioning pel forming elements, associate measurement data with the plurality of non-functioning pel forming elements, the compensation transfer functions and the plurality of tint levels and determine optimal compensation by selecting the compensation transfer functions that have corresponding measurement data values closest to compensation target values for each of the plurality of tint levels.