Printhead Position Correction Using Media-Aware Test Pattern Reading
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Solution Overview
Problem
Inkjet printing apparatuses with full-line printheads face errors in printhead mounting positions, leading to ink droplet landing position deviations and deteriorated printing quality, which existing print position adjustment methods fail to adequately address.
Innovation Solution
A printing apparatus with a data acquisition unit to read test patterns on a recording medium, adjusting light source irradiation and reading quantities based on medium characteristics, and a control unit to control image printing accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a full-line printhead is used to print on the entire surface of a recording medium, then printing efficiency is improved, but mounting position errors cause ink droplet landing position deviations
Solution Approach 1:
The patent implements a feedback mechanism where the reading unit reads the test pattern printed on the recording medium, detects actual ink droplet landing positions, and the control unit calculates correction values based on the difference between intended and actual positions. These correction values are then applied to adjust subsequent printing operations, creating a closed-loop system that compensates for mounting position errors in full-line printheads.
Solution Approach 2:
The patent adjusts printing parameters dynamically by changing the ejection timing and position of ink droplets based on detected deviations. The control unit modifies printing parameters such as ejection timing offsets and position corrections to compensate for mounting errors, allowing the system to maintain precision despite using full-line printheads for high-speed printing.
2Manufacturing precision
If print position adjustment is performed by reading images and detecting landing positions, then landing position accuracy is improved, but additional processing time is required
Solution Approach 1:
The patent performs print position adjustment as a preliminary maintenance operation before normal printing operations begin. The test pattern is printed and read in advance, correction values are calculated and stored, so that subsequent printing operations can use these pre-computed corrections without real-time processing delays, maintaining both accuracy and speed.
Solution Approach 2:
The patent uses a test pattern that replicates the structure and properties of actual printed images. By printing and reading this test pattern, the system obtains correction data that can be applied to all subsequent printing operations, avoiding the need to read and process every actual printed image for position correction.
3Manufacturing precision
If gray scale correction is applied to each pixel based on recording medium properties, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent applies correction values specifically to regions where printing deviations occur, rather than uniformly processing all pixels. The reading unit detects actual landing positions and the control unit generates targeted correction data for specific printheads and recording medium combinations, applying corrections only where needed based on detected local deviations.
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
Enhances printing quality by dynamically adjusting ink droplet landing positions, improving image accuracy and consistency across various recording media types.
Implementation Method 1
read data of a test pattern printed on the recording medium by a reading operation for reading, by a reading unit, reflected light of light irradiated on the recording medium from a light source
Data Source
AI summary
A printing apparatus acquires characteristic information about a recording medium and executes a light quantity adjustment in a reading operation using a reading unit based on the acquired characteristic information. By using the above-described configuration, it is possible to prevent an increase in the number of processes for analyzing read data obtained by reading a test pattern.