Inkjet Printing Landing-Position Feedback for Bidirectional Scan Alignment
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Solution Overview
Problem
Existing printing technologies face challenges in maintaining consistent ink droplet landing positions due to changes in viscosity and environmental conditions, leading to deviations in printed image quality, particularly in bidirectional printing.
Innovation Solution
A printing device and method that includes a detection unit to detect droplet landing positions during a main scan, allowing the control unit to adjust the timing of droplet ejection in subsequent scans to minimize deviations in landing positions, using sensors to correct for changes in ink droplet trajectories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink droplets are ejected from the nozzle array while the printing head is moving in the main scan direction, then printing can be performed efficiently with the printing head reciprocating along the main scan direction, but the position of the nozzle array at ejection time and the landing position of the ink droplet differ in the main scan direction, causing deviation in printed image quality
Solution Approach 1:
The control unit预先 calculates the movement amount of the printing head in the main scan direction during the droplet flight time, and预先 adjusts the ejection timing or position to compensate for the expected deviation between ejection position and landing position, ensuring accurate image formation despite the printing head's movement
Solution Approach 2:
The detection unit detects the actual landing position of ink droplets on the medium, and the control unit uses this feedback information to adjust the ejection timing or position in subsequent printing operations, thereby correcting deviations and maintaining image quality
2Manufacturing precision
If the speed of ink droplets ejected from the nozzle array changes due to change in viscosity, environmental temperature, or distance from nozzle array to medium, then the ink droplet landing position deviates from the intended position, but adjusting ejection parameters to compensate for these changes reduces printing efficiency
Solution Approach 1:
The detection unit continuously monitors the actual landing positions of ink droplets, and the control unit uses this real-time feedback to dynamically adjust ejection parameters (timing, position, or speed), automatically compensating for changes in ink viscosity, temperature, or nozzle-to-medium distance without requiring manual intervention or reduced printing speed
Solution Approach 2:
The control unit changes ejection parameters (such as ejection timing, position, or droplet speed) based on detected landing position deviations, adapting the printing process to compensate for variations in ink properties and environmental conditions while maintaining consistent image quality
3Productivity
If bidirectional printing is performed with ink droplets ejected in both outward and return routes during main scans, then printing productivity is improved, but the position of the ruled line on the outward route and the position of the ruled line on the return route deviate depending on change in state
Solution Approach 1:
The detection unit detects landing positions of ink droplets in both outward and return route main scans, and the control unit uses this feedback to adjust ejection parameters for each direction independently, compensating for deviations caused by changes in printing head speed, ink viscosity, or environmental conditions during bidirectional printing
Solution Approach 2:
The control unit applies different ejection parameter adjustments for the outward route and return route based on their respective detected landing position deviations, optimizing each direction's printing parameters independently to maintain line position consistency across the entire printed image
Data Source
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AI summary
A detection unit includes a sensor that detects a density of locations on a medium on which droplets ejected from a nozzle array during a main scan land while moving along a main scan direction together with a printing head. The detection unit detects landing positions in the main scan direction of the droplets ejected from the nozzle array based on a detection result of the sensor. A control unit controls a plurality of the main scans involving the ejection of the droplets and a sub-scan between the plurality of main scans, based on image data. The control unit controls, based on the landing positions in the main scan direction detected by the detection unit in the first main scan, a timing at which the printing head is caused to eject the droplets in a second main scan to reduce a deviation in the landing position in the main scan direction of the droplets ejected from the nozzle array between the first main scan and the subsequent second main scan.