Offset Printing Blanket Steering for Lateral and Rotational Alignment
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Solution Overview
Problem
Existing offset printing technologies face challenges in maintaining accurate lateral and rotational alignment of the blanket, leading to reduced print quality due to incomplete application or transfer of printing agent.
Innovation Solution
The use of independently pivotable primary and secondary steering rollers, with the primary roller twisting the blanket to correct larger offsets and the secondary rollers stretching to correct smaller offsets, combined with a controller for precise steering control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fixed steering rollers are used, then the device complexity is low, but the manufacturing precision of blanket alignment deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the steering rollers pivotable rather than fixed. The primary steering roller can pivot about a first steering axis, and the secondary steering roller can pivot about a second steering axis perpendicular to the first. This dynamic capability allows the rollers to actively correct blanket lateral and rotational offsets in real-time, significantly improving alignment precision while maintaining reasonable device complexity through modular design.
2Manufacturing precision
If multiple independently pivotable rollers are added, then the manufacturing precision of blanket alignment improves, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the steering function into two independent components: a primary steering roller for lateral alignment and a secondary steering roller for rotational alignment. Each roller has its own pivot axis and actuator, allowing independent control. This segmentation enables precise correction of both lateral and rotational offsets without requiring a single complex multi-degree-of-freedom mechanism, thus improving alignment precision while keeping device complexity manageable.
Solution Approach 2:
The patent implements feedback control through a controller that receives signals from sensors detecting blanket position and orientation. The controller independently actuates the primary and secondary steering rollers based on detected deviations, creating a closed-loop control system. This feedback mechanism ensures high alignment precision by continuously correcting offsets while optimizing the operation of the multiple rollers to avoid unnecessary complexity.
3Manufacturing precision
If blanket alignment is not corrected, then the printing process is simple and fast, but the print quality deteriorates due to incomplete application or transfer of printing agent
Solution Approach 1:
The patent applies preliminary action by correcting blanket alignment offsets before the printing agent application and transfer processes occur. The steering rollers adjust the blanket position and orientation in advance, ensuring proper alignment between the blanket and print substrate before printing begins. This preliminary correction prevents misalignment-related print quality defects without requiring reprints or slow adjustments during the printing process, thus maintaining high productivity while improving print quality.
Data Source
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AI summary
Offset print apparatus comprises a blanket arranged in a closed loop around a plurality of rollers. Each of the plurality of rollers is rotatable about a respective roller axis to support and convey the blanket around the closed loop. The plurality of rollers comprises: a primary steering roller rotatable about a primary roller axis and being pivotable about a primary steering axis perpendicular to the primary roller axis; and a secondary steering roller rotatable about a secondary roller axis and being pivotable about a secondary steering axis perpendicular to the secondary roller axis. The primary and secondary steering rollers are each independently pivotable. The offset print apparatus further comprises an actuator to actuate pivoting of the primary steering roller and the secondary steering roller.