Inkjet Printhead Ejection Timing Control for Paper Distance Fluctuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inkjet printing apparatuses face challenges in maintaining accurate ink droplet placement on print media with low rigidity, as the paper distance fluctuates orthogonally to the printhead's moving direction, leading to inconsistent ejection timings across ejection ports.
Innovation Solution
An inkjet printing apparatus equipped with a printhead, carriage, conveyance unit, platen, and an obtaining unit that measures paper distance at multiple positions, allowing for precise control of ink ejection timing based on this information and the number of passes over a unit area, ensuring consistent ink droplet placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rectangular groove borderless preliminary ejection port is used to enable marginless printing, then printing versatility is improved, but paper distance fluctuation increases causing ejection timing inconsistency
Solution Approach 1:
The invention divides the ejection port structure into multiple segments: a first ejection port array for normal printing and a second ejection port array (borderless preliminary ejection port) for marginless printing. This segmentation allows the system to switch between different ejection patterns based on printing requirements, maintaining both versatility and precision for each specific function.
Solution Approach 2:
The invention applies different ejection control strategies to different regions of the printhead. The central portion ejection ports use one timing control method while the end portion ejection ports use another timing control method. This local differentiation compensates for the paper distance fluctuation caused by the rectangular groove structure, ensuring consistent ejection timing across all ports despite the structural deformation.
2Reliability
If the platen includes a suction mechanism for stable print medium holding, then holding reliability is improved, but paper deformation occurs leading to paper distance fluctuation
Solution Approach 1:
The invention implements position-dependent ejection timing control where the central portion ejection ports and end portion ejection ports use different timing adjustments. This local differentiation compensates for the non-uniform paper deformation caused by the suction mechanism, maintaining both reliable holding and consistent ejection timing across the printhead array.
3Device complexity
If ink ejection timing is controlled based on single position paper distance measurement, then control simplicity is maintained, but ejection precision deteriorates due to paper distance variation across ejection ports
Solution Approach 1:
The invention segments the ejection port array into a central portion and an end portion, applying different timing control methods to each segment. This segmentation approach balances control complexity with precision by implementing position-specific corrections only where needed, rather than requiring complex comprehensive control for all ports.
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
This solution enables high-quality image printing by accurately adjusting ink ejection timing, reducing image quality deterioration due to paper distance fluctuations, particularly on low-rigidity media.
Implementation Method 1
a reflective optical sensor that detects a distance from the ejection port surface to the print medium
Implementation Method 2
an ink droplet ejected from the printhead drops on the print medium at a position downstream, in the moving direction, of the position of the ejection port where the ink droplet was ejected
Data Source
AI summary
An inkjet printing apparatus includes a printhead in which a plurality of ejection ports that eject ink are formed, a carriage mounted with the printhead and reciprocated in a predetermined direction, a conveyance unit to convey a print medium, a platen to support, at a printing position, the conveyed print medium, and an obtaining unit to obtain information regarding a distance from an ejection port surface of the printhead to the print medium at positions in the predetermined direction. The apparatus controls an ink ejection timing in accordance with the information regarding the obtained distance and information corresponding to the number of passes of printing, which is the number of times of moving the carriage to print the image in a unit area of the print medium.