Shear-mode Ink Jet Head Density Correction via Nozzle Grouping

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Solution Overview

Problem

Shear-mode ink jet heads experience density nonuniformity issues at the ends of images and at the joints of head modules, leading to increased ink quantity and density, which conventional solutions fail to completely resolve.

Innovation Solution

The ink jet printer splits nozzles into groups and implements density correction control by adjusting the drop amount of target nozzles based on adjacent non-jetting nozzles, ensuring equal drop amounts are jetted from adjacent nozzles to reduce density nonuniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If nozzles at both ends are surrounded by other nozzles in a shear-mode ink jet head, then the structure is compact and functional, but the quantity of jetted ink becomes unstable and density increases at the end of an image

Engineering Contradiction:

Improvehead structureVSAvoiddensity uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies different structures to different parts of the head: outermost nozzles have a different configuration (with only one adjacent nozzle) compared to inner nozzles (surrounded by two nozzles). This local differentiation resolves the density nonuniformity issue at image ends while maintaining the overall compact structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of making all nozzles identical with two adjacent nozzles each, the patent inverts the approach by making the outermost nozzles have only one adjacent nozzle, reversing the conventional symmetric arrangement to solve the end-of-image density problem.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If multiple shear-mode ink jet heads are arranged to increase printing width, then productivity increases, but density nonuniformity becomes conspicuous at the joint of heads

Engineering Contradiction:

Improveprinting widthVSAvoiddensity uniformity at joint

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent creates a local transition zone at the joint of multiple heads where the nozzle configuration changes gradually. This local structural adaptation at the joint area reduces density nonuniformity while maintaining high productivity through multiple head arrangement.

Inventive Principle:

Principle #3Local quality

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 effectively reduces density nonuniformity at the ends of images and joints, improving print quality by ensuring consistent ink distribution and preventing conspicuous density increases.

Implementation Method 1

two piezoelectric members polarized in a mutually opposite direction in a direction of the thickness are pasted

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS7874632B2Ink jet printer

Publication Date: 2011.01.25 RISO KAGAKU CORP

AI summary

In order to settle a phenomenon that a quantity of jetted ink increases at the end of an image and a density increases in a shear-mode ink jet head, in a three-split driven head, a first group prints so that a diameter of a dot is reduced by reducing the quantity of jetted ink as dots at both ends, a second group similarly prints, and a third group also similarly prints. Since three dots at both ends in a main scanning direction of an acquired image are smaller than dots in the middle, the phenomenon that a quantity of jetted ink increases at the end of the image and density increases is reduced.