Print Head Alignment Mechanism Using Self-Service Scanning
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Solution Overview
Problem
Manufacturing variations often result in misalignment of print heads in color printers, leading to degraded print quality with printed lines appearing as laterally displaced segments, necessitating an accurate method to compute misalignment between print heads.
Innovation Solution
A printing system with a print engine, scanner, and alignment system that generates an alignment chart to compute the magnitude of misalignment between print heads, using a test pattern printed on a medium, scanned, and processed to calculate absolute and relative offsets for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If software-based alignment adjustment is used to correct manufacturing variations, then print quality can be improved, but the complexity of the alignment system increases due to the need for precise misalignment computation and multiple adjustment parameters
Solution Approach 1:
The system uses the print heads themselves to print the alignment chart, and the scanner (already present in the printing system) to scan it, eliminating the need for external alignment equipment. The computation is performed by the existing processor, making the alignment function self-contained and reducing additional system complexity
Solution Approach 2:
The alignment chart is printed as a test pattern that replicates the actual printing process, allowing the system to measure misalignment using a copy of the printing output rather than requiring complex direct measurement of print head positions
2Manufacturing precision
If alignment computation is performed to correct misalignment between print heads, then printed line quality improves, but the time required for alignment setup and calibration increases
Solution Approach 1:
The system performs alignment calibration during the manufacturing or setup phase before actual printing operations begin. The alignment chart is printed once, scanned once, and the misalignment parameters are computed and stored for use in all subsequent printing operations, making the time investment one-time rather than recurring
Solution Approach 2:
The system adjusts timing parameters and ejector selection to compensate for misalignment, changing operational parameters rather than physical positions. This software-based adjustment is computationally fast and can be applied immediately without mechanical repositioning
Data Source
AI summary
A printing system is disclosed. The printing system includes a print engine including two or more print heads to generate an alignment chart and an alignment system. The alignment system receives the alignment chart and computes a magnitude of misalignment between the print heads.