Nozzle Array Dispersion Correction via Pre-Recorded Patterns

Solution Overview

Problem

Ink-jet heads in image recording apparatuses often experience dispersion in ink droplet ejection amounts among nozzles, leading to density nonuniformity in recorded images, particularly due to production errors.

Innovation Solution

A liquid droplet ejecting apparatus with a nozzle array and a relative movement mechanism, controlled by a controller to record nonuniformity correction patterns that adjust ink droplet ejection densities across nozzles, ensuring uniformity by thinning or thickening patterns accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If recording is performed by repeating recording pass and conveyance action, then recording coverage is improved, but density nonuniformity appears in conveying direction due to ejection amount dispersion among nozzles

Engineering Contradiction:

Improverecording coverageVSAvoiddensity uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by recording a nonuniformity correction pattern before actual image recording. The correction pattern includes first and second pattern groups with varying densities that compensate for ejection amount dispersion. By pre-correcting the nozzle characteristics through this pattern, subsequent recording passes produce uniform density without requiring rework.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the ejection parameter (droplet amount) for different nozzles based on their individual characteristics. The controller adjusts the ejection amount of each nozzle group to compensate for dispersion, transforming the uniform ejection parameter into a non-uniform corrected parameter set that accounts for manufacturing variations among nozzles.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If line head with nozzles arranged over entire recording paper length is used, then recording efficiency is improved, but density nonuniformity appears in conveying direction due to ejection amount dispersion

Engineering Contradiction:

Improverecording efficiencyVSAvoiddensity uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by recording a nonuniformity correction pattern before actual image recording. The correction pattern includes first and second pattern groups with varying densities that compensate for ejection amount dispersion. By pre-correcting the nozzle characteristics through this pattern, subsequent recording passes produce uniform density without requiring rework.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the ejection parameter (droplet amount) for different nozzles based on their individual characteristics. The controller adjusts the ejection amount of each nozzle group to compensate for dispersion, transforming the uniform ejection parameter into a non-uniform corrected parameter set that accounts for manufacturing variations among nozzles.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If ejection amount is increased to compensate for low ejection nozzles, then uniformity is improved, but over-ejection occurs at high ejection nozzles causing nonuniformity

Engineering Contradiction:

Improveejection uniformityVSAvoidover-ejection nonuniformity

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by dividing nozzles into multiple groups and assigning different ejection characteristics to each group. Instead of using a single uniform ejection parameter for all nozzles, the controller selectively adjusts the ejection amount for each nozzle group based on its specific characteristics, ensuring that each local region (nozzle group) operates at its optimal ejection level.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the ejection parameter (droplet amount) for different nozzles based on their individual characteristics. The controller adjusts the ejection amount of each nozzle group to compensate for dispersion, transforming the uniform ejection parameter into a non-uniform corrected parameter set that accounts for manufacturing variations among nozzles.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11813869B2Liquid droplet ejecting apparatus

Publication Date: 2023.11.14 BROTHER KOGYO KK

AI summary

A liquid droplet ejecting apparatus comprises a liquid droplet ejecting head which has a nozzle array composed of a plurality of nozzles arranged in a first direction, a relative movement mechanism which relatively moves the liquid droplet ejecting head and a recording medium in the first direction, and a controller. The controller controls the liquid droplet ejecting head and the relative movement mechanism to record, on the recording medium, a nonuniformity correction pattern in order to correct any dispersion in a liquid droplet ejection amount among the plurality of nozzles. The controller is configured, in order to record the nonuniformity correction pattern, such that the liquid droplet ejecting head is allowed to eject liquid droplets from at least the first nozzle to thereby record a first pattern group, the relative movement mechanism is allowed to relatively move the liquid droplet ejecting head and the recording medium in the first direction by a predetermined distance, and the liquid droplet ejecting head is allowed to eject the liquid droplets from at least the second nozzle to thereby record a second pattern group.