Drive Gears for Digital Printing Registration

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Solution Overview

Problem

In roll-to-roll digital printing systems, maintaining precise registration between multiple printing stations is challenging due to disturbances in web transport, leading to registration errors and defects in printed patterns.

Innovation Solution

The design of a web transport system where web transport rollers, including drive rollers, are constrained to rotate an integer number of times as the web advances between successive print locations, ensuring all rollers remain in phase and reducing motion disturbances, thereby minimizing registration errors between image data printed by different printheads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional web transport systems are used without integer rotation constraints, then the system is simpler to manufacture and operate, but registration errors occur between printing stations due to roller run-out and motion disturbances

Engineering Contradiction:

Improveregistration precisionVSAvoidweb transport system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the rotational parameter of web transport rollers by constraining them to rotate an integer number of times between successive print locations. This parameter change ensures that rollers return to the same angular position (phase) after each web cycle, eliminating cumulative registration errors caused by roller run-out and motion disturbances while maintaining system simplicity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements periodic action by ensuring that web transport rollers complete an integer number of rotations between print locations. This periodic constraint causes the rollers to return to their initial angular position repeatedly, creating a consistent phase relationship that minimizes registration errors across multiple printing cycles without requiring complex active control systems.

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If web transport rollers are constrained to rotate an integer number of times, then registration precision is improved, but the device complexity increases due to additional constraints and synchronization mechanisms

Engineering Contradiction:

Improveregistration precisionVSAvoidgear train complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a gear train as an intermediary mechanism between the drive motor and web transport rollers. The gear train acts as a mediator that translates motor rotation into precise integer rotations of the web transport rollers, enabling the integer rotation constraint to be implemented through mechanical means rather than complex electronic control systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex electronic control systems with a mechanical gear train solution. By using mechanically constrained gear ratios, the system achieves integer rotation constraints through pure mechanical means, simplifying the overall control architecture while maintaining registration precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If rollers are kept in phase with integer rotations, then registration errors are reduced, but the system requires more precise manufacturing and assembly

Engineering Contradiction:

Improveregistration precisionVSAvoidsystem sensitivity to manufacturing tolerances

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

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 approach enhances registration precision and reproducibility by maintaining consistent roller phases, reducing registration errors and improving the quality of composite printed patterns.

Implementation Method 1

one or more drive rollers for causing the web of media to move along the web transport path, the drive rollers having an affixed driven gear driven by a motor using a gear train including one or more drive gears which transfer torque from the motor to the driven gear

Methodology Applied

Scientific EffectGear: Gear

Data Source

PatentUS9145014B1Drive gears providing improved registration in digital printing systems

Publication Date: 2015.09.29 EASTMAN KODAK CO

AI summary

A printing system for printing on a web of media traveling along a web transport path, including a plurality of printheads for printing on the web of media, each of the printheads being configured to print at one or more corresponding print locations along the web transport path. A plurality of web transport rollers guide the web of media along the web transport path. A drive roller causes the web of media to move along the web transport path. The drive roller has an affixed driven gear driven by a motor using a gear train including one or more drive gears which transfer torque from the motor to the driven gear. The driven gear and the drive gears are constrained to rotate substantially an integer number of times as the web of media is advanced along the web transport path between two successive print locations.