Printhead Pixel Offset Control for Stripe-Free Solid Printing
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Solution Overview
Problem
Existing printing technologies fail to effectively suppress the formation of stripe-shaped gaps between dots in solid coated portions, particularly when printing at higher resolutions in directions perpendicular to the medium transport, leading to poor dot filling and visible banding.
Innovation Solution
A printing device and method that adjusts the relative movement of the head and medium to form dots longer in the direction perpendicular to the primary scanning direction, using a control section to offset pixel columns by a predetermined distance less than the inverse of the primary resolution, creating a checkerboard pattern to minimize stripe-shaped gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If dots are thinned out in a checkerboard pattern and the size of dots that are not thinned out is increased, then the occurrence of banding is suppressed, but when printing at higher resolution in the transport direction, laterally elongated dots are formed and stripe-shaped gaps still occur
Solution Approach 1:
The invention intentionally forms laterally elongated dots (asymmetric dot shape) rather than circular dots, and offsets pixel columns asymmetrically in the main scanning direction. This asymmetric approach prevents the formation of regular stripe patterns while maintaining high resolution in the transport direction, thereby suppressing banding without sacrificing dot filling uniformity.
Solution Approach 2:
The invention addresses the one-dimensional banding problem by introducing offset in the main scanning direction (perpendicular dimension to transport direction). By offsetting pixel columns in this another dimension, the invention disrupts the stripe pattern formation while maintaining the high resolution requirement in the transport direction.
2Object-affected harmful factors
If pixel columns are offset by a predetermined distance less than the inverse number of the first resolution, then stripe-shaped gaps are minimized, but the complexity of the control section increases
Solution Approach 1:
The invention changes the positioning parameter of pixel columns by introducing a specific offset distance (less than the inverse number of the first resolution) in the main scanning direction. This parameter change effectively minimizes stripe-shaped gaps while the control logic remains relatively simple, requiring only basic position calculation and adjustment.
3Manufacturing precision
If dots are formed longer in the second direction than in the first direction, then dot filling is improved, but the shape control requires precise positioning
Solution Approach 1:
The invention performs preliminary offset adjustment of pixel columns in the main scanning direction before dot formation. By pre-positioning the pixel columns with the appropriate offset, the subsequent dot formation process naturally produces the desired laterally elongated shape with improved dot filling, reducing the need for complex real-time positioning adjustments.
Data Source
AI summary
A printing device includes a head in which a plurality of nozzles configured to form dots by ejecting liquid onto a medium are arranged in a first direction, a first scanning section that performs a first scan, a second scanning section on which the head is mounted, the second scanning section and the medium moving relatively in a second direction, and a control section that causes the head to form the dots that are longer in the second direction than in the first direction, based on a pixel data group, wherein when printing is executed based on a pixel data group in which the first resolution is smaller than the second resolution, the control section offsets at least a part of the pixel columns from other pixel columns in the first direction by a predetermined distance that is less than an inverse number of the first resolution.