Inkjet Printhead Discharge Position Correction for Image Quality

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Solution Overview

Problem

Printing apparatuses face image quality deterioration due to ink discharge position shifts between outgoing and return paths, leading to irregular air streams and reduced accuracy in ink landing positions.

Innovation Solution

The printing apparatus discharges ink as first and second liquid droplets, with a determination section deciding whether to perform discharge position alteration correction based on the discharge amount per unit area, preventing corrections that could worsen image quality by moving the discharge position along the transport direction and ensuring non-overlap of droplets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If discharge position alteration correction is performed to compensate for ink landing position shifts, then image quality should be improved, but image quality deteriorates due to irregular air streams caused by high ink discharge amounts

Engineering Contradiction:
Improveink landing position accuracyVSAvoidimage quality deterioration
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the parameter of ink discharge amount by selectively omitting discharge position alteration correction for liquid droplets in regions where the discharge amount per unit area exceeds a threshold. This parameter change prevents the formation of irregular air streams that would otherwise cause image quality deterioration, while still applying correction where appropriate to maintain landing position accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of applying discharge position alteration correction uniformly to all liquid droplets, the invention applies partial correction only to droplets where the discharge amount per unit area is within acceptable limits. This partial action approach avoids the harmful effects of excessive ink discharge in certain regions while maintaining correction benefits in other regions.

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If ink is discharged in both outgoing path and return path, then printing productivity is improved, but ink landing position shifts occur between paths

Engineering Contradiction:
Improveprinting speedVSAvoidink landing position consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention uses feedback by calculating the discharge amount per unit area for each liquid droplet and using this information to determine whether discharge position alteration correction should be applied. This feedback mechanism allows the system to adaptively adjust correction application based on local discharge conditions, maintaining both productivity and precision.

Inventive Principle:
Principle #23Feedback

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 image quality by minimizing discharge position alterations, reducing the risk of rippling, and maintaining accurate ink landing, thereby preventing image quality deterioration.

Implementation Method 1

a plurality of nozzles that discharge ink onto the recording medium

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 2

an air stream between the recording medium and the printing section becomes irregular

Methodology Applied
Scientific EffectAerodynamic force: Drag

Data Source

PatentEP3196039B1Printing apparatus and printing method
Publication Date: 2019.03.06 SEIKO EPSON CORP
  • EP3196039B1 patent drawingFigure 1
  • EP3196039B1 patent drawingFigure 2
  • EP3196039B1 patent drawingFigure 3~5

AI summary

A printing apparatus is provided with a printing mechanism section that forms an image by discharging an ink toward a recording medium while reciprocating with respect to the recording medium, a pass analysis section that specifies a discharge position of the ink in an outgoing path and a return path of the printing mechanism section, an execution section that executes discharge position alteration correction, which alters the discharge position so that ink to be discharged in one path of either the outgoing path or the return path, is discharged in the other path, and a determination section that performs determination of whether or not the execution section performs the discharge position alteration correction.