Inkjet Printhead Nozzle Array Registration Adjustment

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Solution Overview

Problem

Ink-jet printing apparatuses face challenges in accurately adjusting dot printing positions due to disturbances such as vibrations and printhead posture variations, leading to precision drops in forming adjustment patterns and density changes, which existing techniques struggle to fully address.

Innovation Solution

A printing apparatus with multiple nozzle arrays, where the first and second nozzle arrays are shifted in the nozzle arrayed direction, and a calculation unit adjusts relative printing positions by forming first and second patterns on the medium, allowing precise adjustment values to be calculated based on density changes, thereby minimizing the impact of disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If droplet size is reduced to improve printing quality, then printing resolution is improved, but disturbances heavily influence ink discharging and dot printing positions

Engineering Contradiction:

Improveprinting resolutionVSAvoidink discharging stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The pattern formation process is segmented into multiple passes using different nozzle arrays. The first nozzle array forms reference patterns, while the second and third nozzle arrays form shifted patterns. This segmentation allows independent control and adjustment of each nozzle array, reducing the impact of disturbances on any single array's performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the parameter of pattern shifting amount systematically. Multiple shifted patterns are created with different shift amounts relative to the reference patterns. By varying this parameter, the system can detect and compensate for position shifts caused by disturbances, maintaining reliable dot printing positions even with reduced droplet sizes.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If visual confirmation method is used for registration processing, then adjustment value can be obtained, but troublesome work is imposed on the user

Engineering Contradiction:

Improveshift amount detectionVSAvoiduser work burden

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The invention replaces the manual visual confirmation method with an automated optical sensing system. An optical sensor automatically reads the adjustment patterns printed on the medium, and a calculation unit automatically calculates the adjustment value based on the sensor readings. This substitution eliminates the need for user visual inspection and manual measurement, significantly reducing the user's work burden while maintaining or improving measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If mechanical precision is enhanced to suppress disturbances, then dot printing position stability is improved, but cost increases

Engineering Contradiction:

Improvedot printing position stabilityVSAvoidapparatus cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention creates multiple copies of patterns with different shift amounts using different nozzle arrays. Instead of relying on high mechanical precision to prevent disturbances, the system produces redundant pattern copies that can be used to detect and compensate for position variations. This approach achieves stability through information redundancy rather than mechanical precision, avoiding increased apparatus cost.

Inventive Principle:

Principle #26Copying

4Measurement precision

If multiple nozzle arrays are used to form patterns, then registration adjustment precision is improved, but device complexity increases

Engineering Contradiction:

Improveregistration adjustment precisionVSAvoidprinthead structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention makes the printhead multi-functional by incorporating multiple nozzle arrays that can independently form patterns. The same printhead structure is used to create reference patterns, shifted patterns, and to detect position variations. This universal structure performs multiple functions (printing, measurement, and compensation) without requiring separate dedicated devices, thereby improving registration precision while limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9421770B2Printing apparatus and printing position adjusting method thereof

Publication Date: 2016.08.23 CANON KK

AI summary

A printing apparatus prints by discharging inks from respective nozzle arrays, the printhead having a plurality of nozzle arrays including at least a first nozzle array, a second nozzle array, and a third nozzle array, and the first nozzle array and the second nozzle array being arrayed to be shifted in a nozzle arrayed direction. The printing apparatus controls the first and second nozzle arrays to discharge inks to form a plurality of first patterns. The printing apparatus controls the third nozzle array to discharge inks to form second patterns while changing a shift amount in a direction which intersects with the nozzle arrayed direction with respect to the plurality of first patterns. The printing apparatus calculates an adjustment value required to adjust relative printing positions between the first nozzle array and the third nozzle array in the intersecting direction using the first patterns and the second patterns.