Print Head Overlap Control for Banding and Thickening
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Solution Overview
Problem
Existing printing technologies face challenges in preventing character thickening and banding during overlap printing, particularly when using multiple nozzles, which can result in defects in printed images.
Innovation Solution
A control device for a printing execution unit that alternately performs partial printing and movement of the printing medium, with specific strategies for printing character and non-character regions in overlap areas to prevent thickening and banding, by ensuring character dots are formed by one partial printing and non-character dots are formed by both partial printings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple nozzles are used for overlap printing to suppress banding, then banding is suppressed, but character thickening occurs
Solution Approach 1:
The patent applies different printing strategies to different regions: character regions are printed by a single nozzle to prevent thickening, while non-character regions use multiple nozzles for overlap printing to suppress banding. This regional differentiation resolves the contradiction by optimizing each region according to its specific requirements.
Solution Approach 2:
The printing process is segmented into character region processing and non-character region processing. The controller identifies character regions and applies a single-nozzle printing strategy, while non-character regions receive multi-nozzle overlap printing. This segmentation allows simultaneous achievement of both goals.
2Manufacturing precision
If single nozzle is used for character printing to prevent thickening, then character thickness is controlled, but banding appears in non-character regions
Solution Approach 1:
The patent implements location-specific printing quality control by identifying character regions and applying single-nozzle printing to maintain precise character thickness, while applying multi-nozzle overlap printing to non-character regions to eliminate banding. This local quality approach resolves the contradiction between character precision and overall image quality.
Solution Approach 2:
The printing area is segmented into character regions and non-character regions, with different printing strategies applied to each segment. Character regions use single-nozzle printing for precision, while non-character regions use multi-nozzle printing for uniformity, thus resolving the banding issue without affecting character quality.
3Stability of the object's composition
If multiple nozzles print the same region to suppress banding, then uniformity is improved, but printing time increases
Solution Approach 1:
The patent segments the printing process into single-nozzle printing for character regions and multi-nozzle overlap printing for non-character regions. This segmentation reduces the overall printing time compared to uniform multi-nozzle printing, while still achieving banding suppression in non-character areas.
Solution Approach 2:
The patent applies multi-nozzle overlap printing only partially, specifically to non-character regions where banding is more noticeable, rather than applying it to the entire printing area. This partial application reduces printing time while still achieving the desired uniformity where it matters most.
Data Source
AI summary
A control device for a printing execution unit, wherein, in a case where a character region and a non-character region are included in an overlap region which includes an upstream end of a partial region configured to be printed by a first partial printing, the printing execution unit is caused to print a print image by: forming a plurality of character dots, which are dots in the character region included in the overlap region, by one of the first partial printing and a second partial printing, and not forming the plurality of character dots by another of the first partial printing and the second partial printing; and forming some of a plurality of non-character dots, which are dots in the non-character region included in the overlap region, by the first partial printing, and forming other dots of the plurality of non-character dots by the second partial printing.