Inkjet Printer Misalignment Correction via Concentration Detection
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Solution Overview
Problem
Inkjet printers face challenges in accurately correcting misalignment between ink dots ejected on forward and backward paths during bidirectional printing, as existing methods relying on detecting the lowest concentration may be influenced by unintended light reflection and result in incorrect alignment determination.
Innovation Solution
A printing device with an inkjet head, carriage drive mechanism, and detection mechanism that prints correction patterns with varying intervals, detecting the highest concentration to accurately calculate and correct misalignment between ink dots, ensuring proper alignment by estimating the position where the concentration is lowest based on the detected highest concentration and known intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lowest concentration position is detected to determine alignment, then the correction can be performed, but light reflection from ultraviolet-curable ink causes incorrect detection
Solution Approach 1:
The patent inverts the detection approach by detecting the highest concentration position instead of the lowest concentration position. This inversion resolves the issue where light reflection from ultraviolet-curable ink causes incorrect detection of the lowest concentration position, enabling accurate alignment measurement despite the harmful light reflection effect.
2Manufacturing precision
If correction patterns with varying intervals are printed to enable correction, then misalignment can be corrected, but the device complexity increases
Solution Approach 1:
The correction pattern is segmented into multiple first direction patterns and second direction patterns with different intervals. This segmentation enables the system to measure misalignment at various positions and calculate the optimal correction amount, achieving precise landing position alignment while managing the complexity through systematic pattern division.
3Productivity
If bidirectional printing is performed to improve productivity, then printing speed increases, but misalignment between forward and backward paths occurs
Solution Approach 1:
The patent implements a feedback mechanism where correction patterns are printed during bidirectional printing, the concentrations are detected by an optical sensor, and the detected concentrations are used to calculate and apply correction amounts. This feedback loop enables the system to maintain high printing speed while automatically correcting misalignment between forward and backward paths.
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
This method effectively corrects misalignment between ink dots, ensuring accurate alignment and improved printing quality even with ultraviolet-curable ink, which tends to reflect light unevenly, by focusing on the highest concentration detection for precise correction.
Implementation Method 1
the concentrations of the correction pattern detected by a reflective optical sensor
Data Source
AI summary
Misalignment between landing positions is appropriately corrected. A printing device 10 that performs printing by an inkjet method includes an inkjet head 102, a carriage 100, a main scan driving part 18 (carriage drive mechanism), a detection mechanism 106, and a controller 30. The controller 30 detects a position where a concentration is the highest among concentrations of a correction pattern changing depending on positions in a main scanning direction, calculates magnitude of misalignment between a landing position of ink ejected from the inkjet head 102 when the carriage 100 moves to a first direction side and a landing position of the ink ejected from the inkjet head 102 when the carriage 100 moves to a second direction side based on a detection result of the position where the concentration is the highest, and corrects the misalignment between the landing positions based on a calculation result.