Ejection Apparatus Elongation Compensation Control
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Solution Overview
Problem
In ink jet recording apparatuses, displacement occurs between the ejection positions of different ejection units on a recording medium due to elongation of the medium during conveyance, leading to misalignment and quality issues, especially when the ejection timing of the second ejection unit is constant regardless of the medium's elongation.
Innovation Solution
An ejection apparatus with a first ejection unit, a detection unit downstream of the first ejection unit, and a control unit that predicts the elongation of the recording medium based on detection time differences and adjusts the ejection timing of the second ejection unit to prevent displacement by performing delay control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ejection timing of the second ejection unit is kept constant, then the ejection process is simple and fast, but displacement occurs between ejection positions due to recording medium elongation
Solution Approach 1:
The system performs preliminary detection of the recording medium's arrival time using a detection unit, then uses this information to predict elongation and calculate the required delay time for the second ejection unit before actual ejection occurs. This preliminary measurement and calculation enable precise positioning despite medium elongation.
Solution Approach 2:
The system establishes a feedback loop where the detection unit measures the actual arrival time of the recording medium, the control unit calculates the elongation based on this feedback, and then adjusts the ejection timing of the second ejection unit accordingly. This closed-loop control ensures accurate ejection positions even when elongation varies.
2Manufacturing precision
If the ejection timing is adjusted based on elongation prediction, then ejection position alignment is improved, but the control process becomes more complex
Solution Approach 1:
The system uses the recording medium itself to generate the timing signal for adjustment. The detection unit detects when the medium arrives, and this detection signal directly serves as the basis for calculating the delay time. The medium's own physical presence triggers the correction mechanism, eliminating the need for external sensors or complex measurement systems.
Solution Approach 2:
The system replaces complex mechanical measurement and adjustment mechanisms with an electronic control approach. Instead of using mechanical gauges or physical adjustment devices, the system uses electronic detection of medium arrival time, computational prediction of elongation, and electronic timing adjustment of the ejection units.
3Ease of operation
If no delay control is applied to the second ejection unit, then the device operation is simple, but displacement between ejection positions occurs
Solution Approach 1:
The system dynamically changes the timing parameter of the second ejection unit based on the detected elongation. Instead of using a fixed ejection timing, the control unit adjusts the delay time parameter according to the actual medium conditions, allowing the system to adapt to varying elongation while maintaining operational simplicity.
Data Source
AI summary
An ejection apparatus includes: a first ejection unit configured to eject droplets on a recording medium conveyed in a conveyance direction to form an image for detection; a first detection unit disposed downstream of the first ejection unit and configured to detect the image for detection; a second ejection unit disposed downstream of the detection unit and configured to eject droplets on the recording medium; and a control unit configured to: predict a first elongation amount of the recording medium based on a first difference between a first set time period and a first detection time period from a reference time point to a first detection time point when the image for detection is detected by the first detection unit; and perform delay control on the second ejection unit for delaying an ejection timing of the second ejection unit based on the predicted elongation amount.