Inkjet Recording Head Bidirectional Positioning Adjustment

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Solution Overview

Problem

In serial-type inkjet recording apparatuses, uneven image density occurs due to variations in nozzle diameters and ejection directions, and adjusting recording positions between forward and backward scannings is challenging, especially when unexpected displacement occurs, leading to image non-uniformity and density fluctuations.

Innovation Solution

A recording apparatus and method that employs time division driving of the recording head, where the nozzles are divided into blocks and driven sequentially, allowing for accurate adjustment of ink ejection timings and positions between forward and backward scannings, using a multi-value mask pattern to ensure uniform ink droplet arrangement across the image area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bidirectional recording is performed by repeating forward and backward scanning, then recording efficiency is improved, but recording position displacement occurs leading to image non-uniformity

Engineering Contradiction:
Improverecording efficiencyVSAvoidrecording position accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing registration adjustment before actual recording. The system records test patterns in forward and backward directions, measures the displacement between them, and calculates correction values in advance. These correction values are then applied to the recording head positioning system before production recording begins, preventing position displacement issues during actual recording operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by measuring the actual displacement between forward and backward scanning patterns using detection means, comparing this measured displacement against desired positioning accuracy, and automatically adjusting the recording head positioning based on the difference. This closed-loop feedback system continuously corrects positioning errors that occur during bidirectional scanning.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If multi-pass recording is used to suppress uneven density, then image uniformity is improved, but unexpected displacement between scannings occurs causing image non-uniformity

Engineering Contradiction:
Improveimage uniformityVSAvoidrecording position stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system performs preliminary registration adjustment before multi-pass recording by measuring displacement between forward and backward patterns and pre-calculating correction values. These corrections are applied beforehand to stabilize recording positions across multiple passes, preventing the unexpected displacement that would otherwise cause image non-uniformity during multi-pass recording.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes positioning parameters dynamically by adjusting recording head positions based on measured displacement patterns. The system modifies ejection timing and positioning coordinates as correction values derived from registration adjustment measurements, compensating for unstable recording positions that occur during multi-pass recording operations.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If test patterns with varied figures are used for adjustment discrimination, then adjustment pattern discrimination becomes easier, but adjustment accuracy deteriorates when displacement is small

Engineering Contradiction:
Improvepattern discrimination easeVSAvoidadjustment accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces visual/mechanical pattern discrimination with optical detection and electronic processing. Instead of relying on human visual inspection of varied test patterns, the system uses detection means to optically measure the actual positions of recorded patterns and electronically calculate precise displacement values. This substitution enables accurate measurement of small displacements that would be imperceptible through visual pattern discrimination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3144150B1Recording apparatus and recording method
Publication Date: 2021.03.31 CANON KK
  • EP3144150B1 patent drawingFigure 1A~1B
  • EP3144150B1 patent drawingFigure 2A~2C
  • EP3144150B1 patent drawingFigure 3A~3C

AI summary

A recording apparatus includes a recording head (102) including a plurality of recording elements arranged in a predetermined direction and determination means (E1102) configured to determine a first mode in which a specified image is recorded or a second mode in which a pattern is recorded in each of recording scannings in forward and backward directions to form an adjustment pattern for adjusting a recording position in the intersecting direction of the recording head, and the recording position of the recording head in accordance with the formed adjustment pattern is adjusted, in which driving means (2801) controls driving of the recording elements in a manner that a correspondence relationship between positions in the predetermined direction and the intersecting direction among a plurality of dots that form the same column is varied or is the same in the recording scannings in the forward and backward directions in accordance with the determined mode.