Printing Cleaning Unit Roll Diameter Control for Discharge Head Protection
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Solution Overview
Problem
Existing cleaning methods for discharge heads in printing apparatuses risk damaging the heads due to high-speed sheet conveyance, necessitating a reliable method to compute the roll diameter of the take-up roller for effective ink removal without causing damage.
Innovation Solution
A cleaning unit and method that utilize a feeding roller, take-up roller, wiping roller, and a controller to compute the roll diameter based on the ratio of take-up and feeding rotation speeds, ensuring safe and effective ink removal from discharge heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the take-up roller conveys the sheet at high speed to effectively wipe ink from the discharge head, then the cleaning effectiveness is improved, but the discharge head may be damaged due to excessive sliding speed
Solution Approach 1:
The system dynamically adjusts the take-up roller's rotation speed based on the computed roll diameter of the sheet. By changing the operational parameter (rotation speed) according to real-time conditions, the sheet conveying speed is optimized to ensure effective cleaning while preventing damage to the discharge head.
Solution Approach 2:
The system uses feedback from the roll diameter computation (based on the ratio of take-up to feeding rotation speeds) to adjust the take-up roller's operation. This closed-loop control ensures that the sheet speed remains within the safe and effective range for cleaning the discharge head.
2Object-affected harmful factors
If the sheet is conveyed at a low speed to prevent damage to the discharge head, then the safety is improved, but the cleaning effectiveness deteriorates due to insufficient ink removal
Solution Approach 1:
The system dynamically adjusts the take-up roller's rotation speed based on the computed roll diameter. This parameter adjustment ensures that the sheet conveying speed is optimized to achieve both safety and cleaning effectiveness, resolving the contradiction between low speed (safety) and high speed (cleaning effectiveness).
3Device complexity
If the roll diameter is not accurately computed, then the system complexity is reduced, but the sheet conveying speed control precision deteriorates
Solution Approach 1:
The system uses readily available data (rotation speeds of take-up and feeding rollers) to self-compute the roll diameter without requiring external measurement devices. This self-service approach maintains system simplicity while achieving the precision needed for accurate speed control.
Solution Approach 2:
The system computes roll diameter as a derived parameter from the ratio of rotation speeds, avoiding the need for direct physical measurement. This parameter transformation maintains control precision while minimizing system complexity.
Data Source
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AI summary
The ratio of the rotation speed Nr of the take-up roller 62 (take-up rotation speed) and the rotation speed Nu of the feeding roller 61 (feeding rotation speed) is used. That is, knowledge that the roll diameter Drr of the sheet S taken up on the take-up roller 62 is given by a function using the ratio of the rotation speeds Nr and Nu as a variable was obtained. Accordingly, the roll diameter Drr is computed from this ratio.