Adaptive Media Feed Roller Positioning for Print Quality

Solution Overview

Problem

Imaging apparatuses face a tradeoff between precision in media sheet placement and throughput, as improved precision often reduces printing speed, leading to defects from misalignment between the printhead and the media surface.

Innovation Solution

The method involves adaptive absolute/relative media feed roller positioning, where a controller selects between absolute and relative positioning based on printing mode, move type, and media type to balance print quality and throughput, using an encoder unit to adjust the media feed roller's position dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If absolute positioning of the media feed roller is used to improve precision, then manufacturing precision is improved, but productivity deteriorates

Engineering Contradiction:

Improvemedia sheet placement precisionVSAvoidprinting speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The system dynamically switches between absolute positioning mode and relative positioning mode based on the printing situation. Absolute positioning is used when high precision is required (e.g., at the beginning of a page or after media changes), while relative positioning is used during continuous printing to maintain speed. This dynamic adaptation resolves the contradiction by allowing the system to optimize for precision when needed and for productivity when possible.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller changes the positioning parameter mode (from absolute to relative) depending on the printing context. By adjusting this control parameter, the system can achieve high precision placement when absolute positioning is activated, while maintaining high productivity when relative positioning is used for routine media feeding operations.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If relative positioning of the media feed roller is used to improve throughput, then productivity is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improveprinting speedVSAvoidmedia sheet placement precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically switches between absolute positioning mode and relative positioning mode based on the printing situation. Absolute positioning is used when high precision is required (e.g., at the beginning of a page or after media changes), while relative positioning is used during continuous printing to maintain speed. This dynamic adaptation resolves the contradiction by allowing the system to optimize for precision when needed and for productivity when possible.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller changes the positioning parameter mode (from absolute to relative) depending on the printing context. By adjusting this control parameter, the system can achieve high precision placement when absolute positioning is activated, while maintaining high productivity when relative positioning is used for routine media feeding operations.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If precise registration is attempted to eliminate print defects, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:

Improveregistration accuracyVSAvoidpositioning time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The system dynamically adjusts the positioning strategy based on whether high precision is actually needed. During continuous printing passes, relative positioning is used which is faster and incurs less time loss. Absolute positioning with higher precision is only activated when necessary (at page boundaries or after media changes), thus minimizing the overall time loss while maintaining registration accuracy when it matters most.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller changes the positioning parameter mode (from absolute to relative) depending on the printing context. By adjusting this control parameter, the system can achieve high precision placement when absolute positioning is activated, while maintaining high productivity when relative positioning is used for routine media feeding operations.

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 reduces visible print defects by optimizing positioning modes, enhancing both print quality and speed, particularly in single-pass modes where relative positioning minimizes defects, while maintaining high quality in multi-pass modes with absolute positioning.

Implementation Method 1

An encoder unit has an encoder electronics module and an encoder wheel connected to the media feed roller for simultaneous rotation therewith. The encoder electronics module is configured to read the encoder wheel.

Methodology Applied

Scientific EffectEncoder feedback: Feedback

Data Source

PatentUS7559711B2Method for controlling media feed in an imaging apparatus

Publication Date: 2009.07.14 BRADY WORLDWIDE INC

AI summary

A method for controlling the media feed of a print media sheet in an imaging apparatus having a media feed roller includes selecting between using absolute positioning of the media feed roller and relative positioning of the media feed roller for various media feed roller moves.