Inkjet Recording Apparatus Pixel Deviation Correction
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Solution Overview
Problem
Conventional inkjet recording apparatuses face challenges in accurately monitoring and correcting pixel deviation of ink ejected from nozzles, which affects the quality of recording, particularly due to the limitations of existing methods that rely on detecting stepwise deviations in a test chart recorded on a continuous sheet.
Innovation Solution
The apparatus employs a control section to form a test chart with lines extending along the recording-medium width direction, allowing for gradual changes in ink ejection timing or conveyance speed, enabling detection and correction of pixel deviation in the recording-medium conveyance direction using a detection section, such as an image density sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test chart is recorded on a continuous sheet to detect stepwise deviation, then pixel deviation can be monitored, but the measurement precision is insufficient for accurate pixel deviation detection
Solution Approach 1:
The patent changes the test chart pattern from stepwise deviation lines to inclined lines with specific slopes. By recording inclined lines at different angles (e.g., 45 degrees) and analyzing their distortion, the system can detect pixel deviation with sub-pixel precision, overcoming the limitation of stepwise deviation measurement.
Solution Approach 2:
The patent introduces a new measurement dimension by using inclined lines instead of horizontal lines. The slope of the inclined line provides an additional dimension for measurement, allowing the detection system to calculate pixel deviation based on the line's angle and position changes, thereby achieving higher measurement precision.
2Measurement precision
If conventional test charts with horizontal lines are used, then the apparatus structure remains simple, but pixel deviation in the conveyance direction cannot be accurately detected
Solution Approach 1:
The patent modifies the test chart pattern parameters by using inclined lines with specific angles instead of horizontal lines. This parameter change enables the detection of pixel deviation in the conveyance direction while maintaining a relatively simple apparatus structure, as the inclined line pattern can be generated through standard recording operations.
3Measurement precision
If high-accuracy sensors are used to detect pixel deviation, then measurement precision improves, but the apparatus cost increases significantly
Solution Approach 1:
The patent uses a simple image sensor to capture an optical copy of the inclined line test chart. By analyzing the distorted image of the inclined lines through image processing algorithms, the system can calculate pixel deviation with high precision without requiring expensive specialized sensors, thereby reducing apparatus cost while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces the need for complex mechanical measurement systems or high-precision specialized sensors with a simple image sensor and computational analysis. By using image processing to analyze the inclined line patterns, the system achieves high measurement precision through software-based methods instead of expensive hardware solutions.
Data Source
AI summary
In an inkjet recording apparatus, a control section forms a test chart in which a plurality of lines, each extending along the recording-medium width direction, are drawn arranged along the recording-medium conveyance direction by making the ink ejection nozzles eject ink, while gradually changing either ink ejection timing with respect to each of the ink ejection nozzles or a recording-medium conveyance speed. Furthermore, the control section checks for, and corrects, pixel deviation in the recording-medium conveyance direction based on the test chart.