Printing Apparatus Serpentine Web Position Correction
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Solution Overview
Problem
Current printing apparatuses face challenges in accurately positioning inkjet heads during serpentine web transport, leading to misregister and color shift issues, which are inadequately addressed by existing methods that either require expensive apparatuses or result in discontinuous image printing.
Innovation Solution
The solution involves a printing apparatus with multiple serpentine amount sensors for each printing head, generating predicted waveform data based on differential serpentine amounts, and a correcting unit that adjusts the printing position without altering image data, ensuring precise alignment and minimizing misregister and color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a precise positioning mechanism is used to move the heads for registering, then misregister and color shift are suppressed, but the apparatus becomes expensive
Solution Approach 1:
The patent replaces the mechanical positioning mechanism with a computational approach. Instead of physically moving the inkjet heads to correct misregister, the system calculates the serpentine amount from sensor data, predicts future web position, and shifts the printing data accordingly. This substitution of mechanical adjustment with data processing resolves the contradiction by achieving the same correction function without expensive mechanical components.
Solution Approach 2:
The patent creates a virtual model of the web's serpentine motion through sensor data and uses this copied information to predict future positions. By working with a digital representation rather than physically adjusting the heads, the system achieves precise registration correction without the cost and complexity of mechanical positioning mechanisms.
2Manufacturing precision
If the print data is shifted to correct misregister, then positioning accuracy improves, but discontinuous parts appear in the image causing printing failure
Solution Approach 1:
The patent performs preliminary calculation of the serpentine amount using sensors positioned before the printing heads in the web transport direction. By measuring the web's serpentine motion upstream and predicting its state at the printing location, the system can pre-adjust the printing data to compensate for anticipated misregister, ensuring continuous images are not disrupted by sudden position shifts.
Solution Approach 2:
The system continuously monitors the web's serpentine motion through sensors and uses this feedback to dynamically adjust printing data. The serpentine amount calculated from sensor readings feeds back into the printing control system, enabling real-time compensation that maintains image continuity while correcting positioning accuracy.
3Reliability
If the print data is shifted only at the start of printing the page, then discontinuous parts are avoided, but misregister or color shift becomes large upon completion of printing the page
Solution Approach 1:
The patent calculates the serpentine amount preliminarily using upstream sensors before the web reaches the printing heads. This advance measurement allows the system to predict the web's position throughout the entire page printing process and apply appropriate data shifts continuously, rather than only at the start, thereby maintaining both image continuity and positioning accuracy throughout printing.
Solution Approach 2:
The system uses continuous feedback from serpentine amount sensors to dynamically adjust printing data throughout the page printing process. Rather than applying a fixed shift at the start, the feedback mechanism enables real-time position corrections that maintain accuracy even as the web continues to move and serpentine during the printing of the entire page.
4Device complexity
If the shift amount is obtained directly from the serpentine amount detected by the sensor, then the system is simple, but misregister or color shift is suppressed insufficiently
Solution Approach 1:
The patent performs preliminary calculation of the serpentine amount using sensors positioned upstream before the printing heads. By measuring the web's serpentine motion in advance and predicting its state at the printing location, the system obtains more accurate shift amounts than direct sensor reading would provide, improving positioning precision while adding only minimal computational complexity.
Solution Approach 2:
The patent introduces an intermediary calculation step between the sensor detection and the printing data shift. Instead of directly using the raw serpentine amount, the system processes this intermediate data through prediction algorithms that account for the web's motion between the sensor location and the printing heads, thereby improving accuracy while maintaining relative system simplicity.
Data Source
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AI summary
In printing apparatus, an edge sensor detects a serpentine amount caused by transportation of a web. A predicted waveform data generating unit generates predicted waveform data on the serpentine amount to be produced in the following web in accordance with actually measured waveform data on the detected serpentine amount. A correcting unit corrects a printing position of an image in accordance with a shift amount, and applies a corrected printing position to a printing head. Here, the shift amount is determined with the shift amount determining unit in accordance with the predicted waveform data. Accordingly, the shift amount is determinable in accordance with the actually measured waveform data on the serpentine amount detected with the edge sensor more accurately than that through a method in which a shift amount is directly determined. This allows suppressed misregister.