Media Advance Control for Trailing-Edge Print Quality
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Solution Overview
Problem
Existing printers struggle to achieve high-quality printing on the trailing edge of media due to the absence of advance mechanisms within the print zone, leading to unprinted margins and material waste.
Innovation Solution
A method involving a printer controller that coordinates upstream and downstream media advance mechanisms, using position data from a media advance sensor to control the media advance, switching between open-loop and closed-loop control modes to ensure precise advancement of the media, ensuring high-quality printing on both the leading and trailing edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If advance mechanisms are placed only upstream from the print zone, then the structure is simple, but the trailing edge of media cannot be printed with acceptable quality
Solution Approach 1:
The patent divides the media advancement control into two segments: upstream advance mechanisms for leading edge control and downstream advance mechanisms for trailing edge control. This segmentation allows each mechanism to specialize in controlling media at its respective location, enabling high-quality printing on both edges without requiring a single complex system.
Solution Approach 2:
The patent introduces a media advance sensor as an intermediary that detects media position and provides feedback to the controller. This sensor acts as a mediator between the upstream and downstream advance mechanisms, enabling coordinated control and ensuring precise media advancement throughout the print zone without requiring direct mechanical connection between all components.
2Loss of substance
If no advance mechanisms are present within the print zone, then the device complexity is reduced, but unprinted margins are generated on the trailing edge
Solution Approach 1:
The downstream advance mechanism performs preliminary action by controlling media advancement before the trailing edge reaches the print zone. The media advance sensor detects when the trailing edge approaches the print zone and signals the controller to activate the downstream advance mechanism, ensuring the media is properly positioned before printing occurs, thereby eliminating unprinted margins and reducing material waste.
Solution Approach 2:
The patent implements feedback control by using the media advance sensor to continuously monitor media position and provide real-time information to the controller. This feedback loop enables the system to adjust the downstream advance mechanism's operation dynamically, ensuring precise media positioning throughout the printing process and preventing material waste from unprinted margins.
3Measurement precision
If open-loop control is used for media advance, then the control system is simpler, but precise media advancement cannot be maintained throughout printing
Solution Approach 1:
The patent transitions from open-loop to closed-loop feedback control by introducing the media advance sensor that continuously monitors media position and provides feedback to the controller. This feedback mechanism enables precise measurement and control of media advancement throughout the entire printing process, ensuring accurate positioning of both leading and trailing edges while maintaining manageable system complexity through targeted sensing and control.
Data Source
AI summary
Examples include a method where position data of a media advancing within a print zone are received at a printer controller and from a media advance sensor. An advance of the media by an upstream media advance mechanism located upstream from the print zone is controlled by the printer controller during a first time period. The advance of the media by a downstream media advance mechanism located downstream from the print zone is controlled by the printer controller during a second time period following the first time period and in function of the received position data, whereby a trailing edge of the media passes between the upstream media advance mechanism and the downstream media advance mechanism during the second time period.