Inkjet Density Correction via Feedback and Preliminary Action
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Solution Overview
Problem
Variations in manufacturing tolerances of liquid discharge heads in inkjet image forming apparatuses lead to uneven discharge speed and amount, resulting in density inconsistencies in images formed on recording media, which existing techniques fail to adequately correct.
Innovation Solution
An image forming system that acquires read data of images formed on a recording medium, calculates correction values for image density, and adjusts the image forming process to produce a corrected image, while reporting the relation between density variations and a defined threshold, thereby ensuring uniform image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid discharge heads are manufactured with standard tolerances, then manufacturing cost and ease of manufacture are improved, but density uniformity of the formed image deteriorates due to variations in discharge speed and amount
Solution Approach 1:
The system performs preliminary density measurement and correction value calculation before actual image formation. By measuring the density of test patterns formed by each liquid discharge head and calculating correction values in advance, the system compensates for manufacturing variations before they affect production images, thus maintaining density uniformity without requiring tighter manufacturing tolerances
Solution Approach 2:
The system implements a feedback mechanism where the measured density values from test patterns are used to generate correction values that are then applied to subsequent image formation. This closed-loop feedback allows the system to automatically compensate for discharge variations among liquid discharge heads, resolving the contradiction between ease of manufacture and density uniformity
2Manufacturing precision
If correction values are calculated and applied to adjust discharge amounts, then density uniformity is improved, but device complexity and measurement requirements increase
Solution Approach 1:
The image forming apparatus performs its own self-diagnosis and self-correction by measuring the density of test patterns it forms and automatically calculating correction values. This self-service capability eliminates the need for external measurement devices or complex manual calibration procedures, reducing overall system complexity while maintaining density uniformity
Solution Approach 2:
The system changes the output parameters (drive waveforms) of liquid discharge heads based on measured density values. By adjusting discharge amounts through parameter modification rather than physical modification, the system achieves density uniformity without adding complex mechanical components, keeping the system relatively simple
3Manufacturing precision
If density measurement and correction processes are implemented, then image quality consistency is improved, but processing time and productivity are reduced
Solution Approach 1:
The density measurement and correction value calculation are performed as preliminary actions before actual production image formation. By completing these time-consuming measurements and calculations in advance, the system ensures image quality consistency without significantly impacting production throughput, as the correction values are then applied automatically during normal operation
Solution Approach 2:
The system performs density measurement and correction only for test patterns with specific discharge amounts (e.g., 64% and 96% discharge) rather than all possible discharge levels. This partial measurement approach is sufficient to characterize the discharge characteristics and calculate appropriate correction values, reducing measurement time while maintaining correction effectiveness
Data Source
AI summary
An image forming system includes an image forming apparatus configured to form an image on a recording medium and an output device configured to output information for a user. The image forming system further includes circuitry configured to acquire, from a reading device read data of the image on the recording medium; calculate a correction value of an image density of the read image; cause the image forming apparatus to form, on a recording medium, a corrected image based on the correction value; and acquire, from the reading device, read data of the corrected image; and cause the output device to output report information representing a relation between a density variation value of the corrected image and a threshold of the density variation value.