Digital Printer In-Track Position Error Correction
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Solution Overview
Problem
In digital printing systems with linear printheads, in-track position errors lead to objectionable alignment issues between color channels, requiring a method to characterize and correct these errors without complex and costly fixtures.
Innovation Solution
A digital printing system that includes a method for determining an in-track position correction function by printing and analyzing a test target with alignment marks, allowing for automatic correction of in-track position errors through resampling image data based on measured errors, thereby reducing alignment errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex and costly fixtures are used to correct in-track position errors, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a digital copy (test target image) instead of physical fixtures to characterize and correct in-track position errors. The test target is printed and captured as an image, which is then analyzed to determine position errors and generate correction functions, replacing the need for complex physical measurement fixtures.
Solution Approach 2:
The patent replaces mechanical measurement fixtures with a digital/image-based system. Instead of using physical alignment tools and mechanical measurement devices, the system uses printed test targets, digital image capture, and software analysis to characterize and correct position errors.
2Manufacturing precision
If in-track position errors are not corrected, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The patent performs preliminary characterization of in-track position errors by printing a test target and capturing its image before actual printing. The system analyzes the captured image to determine position errors and generates correction functions in advance, which are then applied during normal printing operations.
Solution Approach 2:
The system uses itself to characterize its own errors by printing a test target and capturing the output. The printed test target is analyzed to determine the printer's actual in-track position errors, and correction functions are generated based on this self-measured data.
3Productivity
If linear printhead is used for digital printing, then productivity is improved, but in-track alignment precision deteriorates due to position errors
Solution Approach 1:
The patent implements a feedback mechanism where the system prints a test target, captures the output image, analyzes it to determine actual position errors, and uses this information to generate correction functions. These correction functions are then applied during printing to compensate for the linear printhead's position errors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces in-track alignment errors in digital printing systems by enabling non-linear corrections for localized alignment characteristics, improving print quality without the need for expensive fixtures.
Implementation Method 1
an electrostatic latent image is formed on a photoreceptor by uniformly charging the photoreceptor and then discharging selected areas of the uniform charge
Implementation Method 2
charged toner particles are brought into the vicinity of the photoreceptor and are attracted to the latent image to develop the latent image into a toner image
Implementation Method 3
A suitable electric field is applied to transfer the toner particles of the toner image to the receiver to form the desired print image on the receiver
Implementation Method 4
The receiver is then removed from its operative association with the photoreceptor and subjected to heat or pressure to permanently fix (i.e., 'fuse') the print image to the receiver
Data Source
AI summary
A digital printing system having a linear printhead includes corrections for in-track position errors. A data processing system implements a method for determining an in-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured in-track position for each of the alignment marks, comparing the measured in-track positions for the alignment marks to reference in-track positions to determine measured in-track position errors, and determining an in-track position correction function responsive to the measured in-track position errors. The in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.