Inkjet Nozzle Density Correction via Scanner Feedback
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Solution Overview
Problem
Existing image recording technologies face challenges in correcting density non-uniformities caused by nozzle ejection failures in inkjet recording apparatuses, as they fail to accurately allocate scan pixel positions to image data pixel positions, leading to inadequate density correction.
Innovation Solution
An image recording apparatus comprising a recording head, conveyance device, test chart output device, image reading device, and density non-uniformity correction device, which acquires reading position information, density information, and recording defect information to calculate and apply correction values, ensuring accurate correspondence and effective density non-uniformity correction even with defective nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference marks are used to allocate density data to nozzles, then density non-uniformity correction is enabled, but correction accuracy deteriorates when ejection failure nozzles are present
Solution Approach 1:
The patent introduces a scanner as an intermediary device to capture test chart images and convert them to density data. This mediator allows the system to obtain actual ejection characteristics without directly relying on nozzle performance, enabling accurate density measurement even when some nozzles fail to eject properly
Solution Approach 2:
The system implements feedback by measuring actual ejection volumes through scanner density readings and using this information to calculate correction values. The correction values are then applied to adjust subsequent ejection amounts, creating a closed-loop system that compensates for nozzle variations and failures
2Device complexity
If scan pixel positions are directly converted to image data pixel positions, then processing is simplified, but position allocation accuracy deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-calculating correspondence relationships between scanner pixels and image data pixels using test charts. This pre-processing step establishes accurate mapping tables that account for scanner-specific characteristics, eliminating the need for complex real-time calculations during actual printing operations
3Manufacturing precision
If ejection volume measurement is performed for all nozzles, then uniform ink ejection is achieved, but measurement time increases
Solution Approach 1:
The system applies partial action by measuring ejection volumes only for nozzles that are actually used in the printing process. By identifying and measuring only the relevant nozzles based on the printable area and print settings, the system achieves necessary ejection uniformity without the time cost of measuring all nozzles in the head
Data Source
AI summary
An image recording apparatus includes: an image reading device which reads a test chart including a density pattern output by a test chart output device; a reading position information acquisition device which acquires reading position information for the density pattern, according to an image of the test chart; a density information acquisition device which acquires reading density information for the density pattern corresponding to the reading position information; a recording defect information acquisition device which acquires recording defect information indicating a recording element having a recording defect; a density non-uniformity correction value calculation device which calculates density non-uniformity correction values for recording elements; a density non-uniformity correction device which performs non-uniformity correction of image data, according to the density non-uniformity correction values; and an image output device which outputs the image data that has been subjected to the non-uniformity correction.