Direct-to-Object Printer Uniform Density on Tapered Surfaces
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Solution Overview
Problem
Direct-to-object printers with high resolution (e.g., 750 dpi in the process direction and 600 dpi in the cross-process direction) struggle to maintain uniform ink image density on objects with varying circumferences, as the existing methods that adjust ink drop volumes are not applicable to these systems, leading to inconsistent image quality on tapered surfaces.
Innovation Solution
A DTO printing system that uses printheads with little or no ink drop volume regulation, employing a controller to modify contone image data and apply a stochastic halftone filter to adjust pixel density, ensuring uniform image density on objects with varying circumferences by adjusting the firing of inkjets based on the object's circumference ratio, rather than varying ink drop volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional 2D printing methods are used on tapered objects, then the printing process is simple, but the ink image density becomes non-uniform on surfaces with varying circumferences
Solution Approach 1:
The system dynamically adjusts printing parameters including inkjet firing frequency, printhead positioning, and rotation speed based on the object's circumference at each position. This allows the printing process to adapt to varying circumferences while maintaining uniform ink density, resolving the contradiction between simple printing processes and precise density control.
Solution Approach 2:
The invention implements a dynamic printing system where the printhead position, inkjet firing timing, and rotation speed are continuously adjusted during the printing process. This dynamic adaptation enables uniform ink deposition on tapered surfaces without requiring complex pre-calculations or fixed printing patterns.
2Manufacturing precision
If ink drop volume variation is used to compensate for circumference changes, then uniform image density can be achieved, but the printhead complexity increases
Solution Approach 1:
Instead of varying ink drop volumes, the system changes other parameters such as inkjet firing frequency and printhead positioning. This approach achieves uniform image density while avoiding the need for complex ink drop volume regulation mechanisms in the printhead.
Solution Approach 2:
The invention inverts the conventional approach by not adjusting ink drop volume to compensate for circumference changes. Instead, it adjusts the timing and positioning of inkjet firing, effectively solving the problem through the opposite methodological approach.
3Manufacturing precision
If high resolution printing is implemented, then image quality improves, but the system's ability to handle varying circumferences deteriorates
Solution Approach 1:
The system dynamically adjusts the inkjet firing frequency and printhead positioning based on real-time circumference measurements. This dynamic control maintains high resolution printing (750 dpi in process direction, 600 dpi in cross-process direction) while adapting to various object geometries and circumference variations.
Solution Approach 2:
The invention changes multiple printing parameters simultaneously including inkjet firing timing, printhead position, and rotation speed to maintain high resolution across tapered surfaces. This multi-parameter adjustment preserves image quality while enhancing adaptability to different object shapes.
Data Source
AI summary
A method of operating a direct-to-object printer adjusts a pixel density of a portion of contone image data for an image to be printed on a surface of a tapered object. The contone image data is also filtered with a stochastic halftone filer to produce binary image data for the image to be printed on the tapered object. The adjustment in the pixel density for the portion of the image to be printed on the portion of the object having a circumference that is different than another portion of the surface at the uppermost portion of the image produces a more uniform appearance in the resulting printed image.