Inkjet Printhead Slant Correction via Data Segmentation
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Solution Overview
Problem
Conventional inkjet printing apparatuses face challenges in achieving high-quality images due to variations in nozzle array orientation between the printhead and carriage scanning direction, leading to incomplete data reading and local loss of images during slant correction.
Innovation Solution
A printing apparatus and method that includes an obtaining unit for determining the slant between the nozzle array and carriage directions, a detection unit for identifying carriage positions, a reading unit for separating image data for first and second scanning, and a control unit to ensure synchronized printing across the same region, allowing for effective slant correction without data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If slant correction is performed by changing the timing at which printing data is read from the print buffer in accordance with the head slant, then the slant of printing dots is corrected, but data may not be completely read, resulting in local loss of image
Solution Approach 1:
The invention segments the image data reading process into multiple phases based on carriage position. The reading unit reads different portions of image data at different timings corresponding to different carriage positions, ensuring complete data retrieval while maintaining slant correction. This segmentation allows the system to address the contradiction by dividing the data reading task into manageable segments that can be completed without loss.
Solution Approach 2:
The invention performs preliminary reading of image data at specific carriage positions before the actual printing occurs. By reading the necessary data portions in advance based on predicted carriage position and slant characteristics, the system ensures complete data availability for slant correction without causing data loss during the printing process.
2Manufacturing precision
If the nozzle array direction is not perpendicular to the carriage scanning direction, then head slant occurs causing printing errors, but adjusting the nozzle array direction is difficult due to manufacturing accuracy and mounting tolerance
Solution Approach 1:
Instead of changing the physical orientation of the nozzle array (which is difficult due to manufacturing and mounting constraints), the invention changes the control parameters - specifically the timing and address management parameters - to compensate for the slant. This allows the system to work with the actual physical constraints while achieving the desired printing precision through software-based parameter adjustment.
Solution Approach 2:
The invention introduces an intermediary correction mechanism through the address management unit and timing control system. This intermediary layer between the physical slanted nozzle array and the desired perpendicular printing pattern allows the system to compensate for the misalignment without requiring physical adjustment of the nozzle array or carriage mounting.
3Loss of information
If printing is done by scanning the same region by first scanning and second scanning, then complete image data can be read and printed, but printing time increases
Solution Approach 1:
The invention performs preliminary identification and reading of necessary image data portions at different carriage positions before the actual printing sequence. By pre-determining which data portions need to be read based on the slant characteristics and carriage position predictions, the system minimizes redundant reading operations and optimizes the timing of data retrieval, thereby reducing the overall time penalty of the multi-pass scanning approach.
Data Source
AI summary
A serial type inkjet printing apparatus performs the following processing. A slant is set between the nozzle arrayed direction and the carriage moving direction for each printing column in the carriage moving direction. The carriage position is detected. Image data stored in a print buffer in association with each printing column is divided based on the detected carriage position and the slant in the printing column corresponding to the set position of the carriage. The image data is read by separating it into respective data used for first-and-second-scan printings by the printhead in an identical region, based on the detected carriage position, and the slant in the printing column corresponding to the set position of the carriage. Printing is performed by first-and-second-scanning the printhead on the identical region, using the read image data.