Inkjet Transport Roller Winding Angles for Print Accuracy
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Solution Overview
Problem
Current inkjet printing apparatuses face reduced printing accuracy due to paper flotation and unevenness caused by wind, which affects the discharge of ink droplets, especially when the approach angle of the printing sheet to the printing unit is close to 0 degrees, leading to increased paper flotation and wind-induced unevenness.
Innovation Solution
The apparatus includes a first transport roller with a winding angle of 75 degrees or more and a second transport roller with a smaller winding angle, ensuring a reduced approach angle and minimizing paper flotation and wind-induced unevenness, while an encoder attached to the first transport roller provides precise control over the transportation speed to enhance printing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the approach angle of the printing sheet to the printing unit is close to 0 degrees, then the transportation speed detection accuracy is improved, but paper flotation amount increases and wind-induced unevenness increases
Solution Approach 1:
The patent changes the approach angle parameter from close to 0 degrees to within a specific range of 5 to 15 degrees. This parameter modification simultaneously reduces paper flotation and wind-induced unevenness while maintaining acceptable transportation speed detection accuracy, thereby resolving the contradiction between measurement precision and manufacturing precision.
2Manufacturing precision
If the approach angle is increased to reduce paper flotation, then paper flotation amount decreases, but wind-induced unevenness increases due to air caught in the gap
Solution Approach 1:
The patent identifies and optimizes the approach angle parameter within the range of 5 to 15 degrees. This specific parameter range achieves the optimal balance by minimizing both paper flotation and wind-induced unevenness, as it reduces air entry into the gap between the printing sheet and printing unit while preventing excessive paper flotation.
3Object-affected harmful factors
If the approach angle is decreased to reduce wind-induced unevenness, then wind-induced unevenness decreases, but paper flotation amount increases
Solution Approach 1:
The patent establishes the approach angle within the optimal range of 5 to 15 degrees. This parameter setting prevents excessive paper flotation by maintaining sufficient downward pressure on the printing sheet, while simultaneously keeping wind-induced unevenness minimal by limiting air entry into the gap.
4Manufacturing precision
If transport rollers are arranged to maintain accurate gap, then printing accuracy is improved, but paper flotation and wind effects occur due to air flow into the gap
Solution Approach 1:
The patent modifies the approach angle parameter to within 5 to 15 degrees, which fundamentally changes the airflow dynamics in the gap between the printing sheet and printing unit. This parameter change reduces air flow into the gap, thereby minimizing wind effects and paper flotation while maintaining accurate gap positioning for high printing accuracy.
Data Source
AI summary
Provided is an inkjet printing apparatus including a first transport roller disposed on a transport path transporting a long print medium, a second transport roller disposed on the transport path downstream of the first transport roller, a print medium holder disposed downstream of the second transport roller, and a recording unit discharging ink droplets to a printing area of the print medium, and performing recording operation, the print medium being transported on the transport path. The first transport roller has a first winding angle upon contact to the print medium. The second transport roller has a second winding angle upon contact to the print medium. The first winding angle is larger than the second winding angle. The first winding angle is equal to or more than 75 degrees. The sum of the first and second winding angles is equal to or more than 80 degrees.