Print Head Protection via Displaceable Spacer for Media Joints
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Solution Overview
Problem
Inkjet printing systems face challenges when dealing with joints in recording media, such as adhesive overlaps or folds, which can damage sensitive print heads and require halting the printing process to adjust the print heads, leading to significant spoilage and reduced productivity.
Innovation Solution
A printing system with a sensor to detect joints, a displaceable spacer element, and an actuator to increase the distance between the print head and recording medium, allowing the system to temporarily deflect the recording medium and protect the print head without halting the printing process, thereby minimizing spoilage and enabling continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the print head is positioned close to the recording medium for precise ink droplet positioning, then printing precision is improved, but the risk of damage from joints (adhesive overlaps, folds, undulations) increases
Solution Approach 1:
A sensor is introduced as an intermediary component between the print head and the recording medium. The sensor detects joints (adhesive overlaps, folds, undulations) in the recording medium and generates signals that trigger the print head to be retracted or positioned away from the joint area, preventing damage while maintaining close positioning during normal operation
Solution Approach 2:
The system performs preliminary detection of joints in the recording medium before the print head reaches that position. The sensor continuously monitors the recording medium surface ahead of the print head, and upon detecting a joint, the system proactively adjusts the print head position in advance to avoid contact, preventing damage before it can occur
2Reliability
If the printing system is halted to adjust print heads into maintenance position upon detecting a joint, then print head protection is improved, but productivity and operational continuity deteriorate
Solution Approach 1:
The print head positioning system is made dynamic and adaptive. Instead of always halting and moving to a fixed maintenance position, the system dynamically adjusts the print head position based on real-time joint detection. The print head can be temporarily retracted or positioned away from detected joints while maintaining overall system operation, allowing selective protection without complete shutdown
3Reliability
If the printing system is halted and print heads are moved to maintenance position for joint passage, then print head safety is improved, but spoilage and time loss increase
Solution Approach 1:
The system enables the recording medium to be rapidly advanced through joint positions without halting the print head. When a joint is detected, the recording medium is quickly moved past the print head area at increased speed, allowing the joint to be skipped over rapidly. This minimizes the time the system is affected by joints while maintaining print head safety
Solution Approach 2:
The sensor acts as an intermediary that enables selective and rapid response to joints. By detecting joints ahead of time and triggering targeted print head retraction or recording medium advancement only at joint positions, the system avoids unnecessary halts and spoilage while maintaining print head safety
Data Source
AI summary
A printing system having: a print head arranged with a predetermined nip for printing to a recording medium; a sensor positioned upstream of the print head, and configured to detect possible joints of the recording medium; a spacer arranged in a region of the print head, the spacer being configured to be displaceable to deflect the recording medium and increasing a distance between the print head and recording medium; an actuator to displace the spacer element; and a controller configured to activate the actuator to displace the spacer upon detection of a joint by the sensor.