Variable Pitch Nozzle Array for Droplet Misalignment

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Solution Overview

Problem

Droplet deposition apparatuses, such as inkjet printers, face challenges in reducing visible artefacts caused by misalignment between adjacent nozzle arrays, leading to noticeable faults like light or dark bands at the seams where adjacent swathes meet, which are time-consuming and expensive to align accurately.

Innovation Solution

The implementation of actuator components with nozzle arrays featuring a combination of constant and variable nozzle pitches, where the variable pitch portions of one array overlap with the constant or further variable pitch portions of another array, creating a Vernier-like mechanism to facilitate the selection of best-aligned nozzles for seamless transitions, thereby minimizing misalignment-induced artefacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple nozzle arrays are arranged in parallel and offset to cover adjacent swathes, then the printing coverage is improved, but visible faults appear at the seams where adjacent swathes meet due to misalignment

Engineering Contradiction:
Improveprinting coverageVSAvoidalignment precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The nozzle array is divided into multiple portions with different pitch characteristics (first portion with constant pitch, second portion with variable pitch). This segmentation allows each portion to serve a specific function: the constant pitch portion maintains regular droplet spacing, while the variable pitch portion compensates for misalignment at transition zones between adjacent nozzle arrays.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the nozzle array are assigned different pitch properties tailored to their specific functional requirements. The variable pitch portion is specifically designed to address the local problem of misalignment at seam transitions, while other portions maintain standard constant pitch for normal printing operations.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If nozzle arrays are carefully aligned to reduce visible faults, then the printing quality is improved, but the manufacturing process becomes time-consuming and expensive

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The nozzle array design is self-aligning through its variable pitch portion, which automatically compensates for misalignment between adjacent arrays. This eliminates the need for expensive and time-consuming external alignment processes, as the structure itself provides the correction mechanism.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pitch parameter is made variable in the second portion of the nozzle array, allowing dynamic adjustment of droplet spacing to compensate for misalignment. This parameter change enables the system to adapt to different alignment conditions without requiring precise manual adjustment during manufacturing.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If constant nozzle pitch is used throughout the array, then the manufacturing simplicity is maintained, but the ability to compensate for misalignment is reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidalignment tolerance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The nozzle array is divided into portions with different pitch characteristics, allowing the system to maintain constant pitch (for manufacturing simplicity) in most areas while introducing variable pitch only in specific portions where misalignment compensation is needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The variable pitch property is applied locally only in the second portion of the nozzle array where it is needed for misalignment compensation, while the first portion maintains constant pitch for manufacturing simplicity. This localized application minimizes the impact on manufacturing while providing the necessary alignment tolerance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3493992B1Arrangement of actuator components for a droplet deposition apparatus, droplet deposition apparatus, method of operating the droplet deposition apparatus and control circuitry for the droplet deposition apparatus
Publication Date: 2022.06.22 XAAR TECH LTD
  • EP3493992B1 patent drawingFigure 1a~1b
  • EP3493992B1 patent drawingFigure 2a~2b
  • EP3493992B1 patent drawingFigure 3a~3b

AI summary

Broadly speaking, embodiments of the present techniques provide apparatus and methods to minimise or reduce the effects of actuator component (and therefore, nozzle array) misalignment. In particular, the present techniques provide an actuator component comprising at least one array of nozzles. In the or each array, the nozzles of the array are arranged in at least two portions: a first portion in which the nozzles in a row of the array are separated by a constant nozzle pitch, and a second portion in the nozzles in a row of the array are separated by a variable nozzle pitch.