Bias Arm Spring Mechanism for Print Media Spacing Control
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Solution Overview
Problem
Inkjet printers often cause curling or cockling of printed media due to changes in physical properties, leading to media jams and print quality defects from interference with print heads and movement issues during printing.
Innovation Solution
The use of bias arms with a pivot point and a spring mechanism to maintain a consistent spacing between the print media and print heads, preventing media contact and allowing for adjustable pressure by replacing springs with different spring constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If printing fluid droplets are deposited onto printable media, then printing function is achieved, but media curling and cockling occur due to changes in physical properties
Solution Approach 1:
The bias arm applies preliminary counteracting force to the print media before and during the printing process to prevent curling and cockling caused by printing fluid deposition. The spring-loaded bias arm continuously presses the media against the platen, creating a pre-compression that opposes the swelling and curling forces generated when ink or printing fluid is applied to the media surface.
2Reliability
If media spacing is not controlled, then media jams occur and print quality deteriorates, but adding complex spacing control mechanisms increases device complexity
Solution Approach 1:
The bias arm system is designed to automatically self-regulate media spacing through the spring mechanism. The spring-loaded bias arm naturally maintains constant contact with the print media, automatically adjusting to different media thicknesses and types without requiring external control systems, sensors, or complex actuation mechanisms. This self-service approach ensures reliable spacing control while keeping the device simple.
3Force
If fixed pressure is applied to maintain media positioning, then media contact with print heads is prevented, but adjustment of pressure requires altering expensive components
Solution Approach 1:
The bias arm incorporates a spring mechanism where the spring constant (stiffness) can be selected based on different printing requirements. By changing the spring parameter (selecting different spring constants), the applied pressure can be adjusted to accommodate various media types, thicknesses, and printing conditions. This parameter-based adjustment allows easy customization of pressure without modifying the overall structure or replacing expensive components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces media jams and maintains print quality by ensuring consistent media positioning and pressure, allowing for easy adjustment of pressure without altering expensive components.
Implementation Method 1
a spring in communication with the second end of the bias arm to bias the first end to contact the platen
Data Source
AI summary
In an example, a printing device can include a pivot point, a bias arm formed of a rigid member to rotate about the pivot point, the bias arm comprising a first end to extend into a print zone and a second end opposite the first end, and a spring in communication with the second end of the bias arm to bias the first end to contact the platen.