Multi-Pass Printing Control Device for Conveyance Error Compensation

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Solution Overview

Problem

Conventional multi-pass printing technologies do not adequately account for both the printing device and the image being printed when modifying the number of passes during the image-forming process, leading to suboptimal printing quality due to conveyance errors.

Innovation Solution

A control device and method that dynamically set the number of scans for a printing unit by determining an acceptable range based on actual conveyance errors and representative values of the printing area, adjusting the number of main scans to ensure appropriate ink dot formation across the printing medium, using a multi-pass execution unit, an acceptable range determining unit, and a number setting unit to execute multi-pass printing with either two or four passes depending on the error and gradation values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the number of passes is fixed for all printing regions, then the printing process is simple, but printing quality deteriorates when conveyance errors occur

Engineering Contradiction:

Improveprinting qualityVSAvoidprinting process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating the number of passes based on the specific printing region's representative input gradation value. Different regions of the printing medium receive different numbers of passes (e.g., 2 passes for low-error regions, 4 passes for high-error regions), allowing each region to be printed with the optimal number of passes suited to its specific requirements and error characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the number of passes variable rather than fixed. The control device dynamically determines the number of passes based on real-time measurement of conveyance errors and the representative input gradation value of each printing region, allowing the printing process to adapt to changing conditions and optimize quality for each specific region.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If the number of passes is increased to compensate for conveyance errors, then printing quality improves, but printing time increases

Engineering Contradiction:

Improveink dot placement accuracyVSAvoidprinting time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent avoids uniformly increasing passes across the entire printing medium by applying local quality. Instead, it determines the number of passes based on the representative input gradation value and conveyance error of each specific printing region, allowing high-precision regions to receive more passes while low-precision regions use fewer passes, thus optimizing the balance between quality and time.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs feedback by measuring actual conveyance errors and using this information to determine the number of passes for each printing region. The control device receives feedback about the conveyance state and adjusts the number of passes accordingly, ensuring that additional passes are only applied where necessary to compensate for measured errors, thereby avoiding unnecessary time consumption in error-free regions.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If a fixed pass number is used, then the printing process is efficient, but it cannot adapt to different conveyance error levels

Engineering Contradiction:

Improveadaptability to conveyance errorsVSAvoidprinting efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by varying the number of passes as a controllable parameter based on the representative input gradation value and conveyance error characteristics of each printing region. This allows the system to adapt to different error levels by adjusting this key parameter, achieving both adaptability and efficiency through data-driven parameter selection.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8833887B2Control device and control method for controlling printing unit to perform multi-pass printing

Publication Date: 2014.09.16 BROTHER KOGYO KK

AI summary

A control device includes an execution unit, a determining unit, and a setting unit. The execution unit controls a printing unit to execute a multi-pass printing for a predetermined partial area of printing medium by executing sub scans and a prescribed number of times of main scans. In the main scan, a print head of the printing unit forms dots on the recording medium while being conveyed in a main scanning direction. In the sub-scan, the printing medium is conveyed in a sub-scanning direction. The determining unit determines an acceptable range based on an actual conveyance error in the sub-scanning direction. The setting unit sets the prescribed number to N when a representative value of predetermined partial area falls in the acceptable range, and sets the prescribed number to M being an integer greater than N when the representative value does not fall in the acceptable range.