Automatic Tuning Compensation for Printhead Gap Inaccuracies

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Solution Overview

Problem

High-speed production printers face issues with visible print artifacts due to inaccurate physical gaps between adjacent printheads, leading to variations in ink deposition and resulting in defects like voids or banding.

Innovation Solution

A printing system that includes a physical memory device to store compensation logic and processors to receive measurement data from print media. It determines optimal compensation by selecting compensation transfer functions that align measurement data values with target values for each tint level, addressing printhead gap inaccuracies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-speed production printing is implemented, then productivity increases, but manufacturing precision deteriorates due to visible print artifacts from inaccurate printhead gaps

Engineering Contradiction:

Improveprinting speedVSAvoidprinthead gap accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary measurement of actual printhead gaps using a measurement device before printing, and pre-calculates compensation transfer functions based on these measurements. This preliminary characterization of the printing system allows high-speed printing to proceed without manual adjustment while maintaining print quality through automated compensation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where measurement data from the print medium is processed to generate compensation transfer functions that are then applied during printing. The system continuously monitors and adjusts for gap variations by comparing actual measurements against target values, enabling high-speed operation while maintaining precision through closed-loop control.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If manual tuning of printhead gaps is performed, then manufacturing precision improves, but loss of time increases due to time-consuming adjustment processes

Engineering Contradiction:

Improveprint uniformityVSAvoidtuning time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs self-characterization by automatically measuring its own printhead gaps and generating compensation parameters without external intervention. The printing system uses built-in measurement devices and processing capabilities to autonomously determine optimal compensation transfer functions, eliminating the need for manual tuning while maintaining print quality.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system replaces manual mechanical adjustment of printheads with an automated digital compensation approach. Instead of physically adjusting printhead positions, the system uses measurement data to calculate and apply compensation transfer functions that correct for gap variations through software-based control of the printing process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If compensation transfer functions are applied to all pel forming elements, then manufacturing precision improves, but device complexity increases due to additional processing requirements

Engineering Contradiction:

Improveink deposition uniformityVSAvoidcompensation processing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system applies compensation selectively based on local characteristics of the printhead array. Compensation transfer functions are generated and applied specifically to pel forming elements affected by printhead gaps, rather than uniformly to all elements. This localized approach maintains print quality while reducing unnecessary processing complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts printing parameters by applying compensation transfer functions that modify ink deposition characteristics based on measured gap variations. The compensation process changes the effective printing parameters (ink amount, positioning) for affected areas, enabling precision correction through parameter optimization rather than structural complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12240254B2Automatic tuning compensation mechanism

Publication Date: 2025.03.04 RICOH CO LTD

AI summary

A printing system is disclosed. The printing system includes at least one physical memory device to store compensation logic and one or more processors 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 pel forming elements in adjacent printheads and a plurality of tint levels, wherein the plurality of pel forming elements comprise gap adjacent pel forming elements that print with applied compensation transfer functions and non-gap adjacent pel forming elements, associate measurement data values with the gap adjacent pel forming elements, the applied 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.