Printer Roller Reflectance Sensor for Media Jam Detection
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Solution Overview
Problem
Conventional printers lack an efficient method for detecting media jams, which are time-consuming and laborious to clear, often requiring physical disassembly to resolve.
Innovation Solution
A sensor unit positioned downstream of the media hub and proximate to a printer roller, comprising a light emitter and detector, generates a sensor signal indicative of reflectance characteristics, with a processor comparing these to a threshold to determine if a media jam has occurred, allowing for timely detection and prevention of further media supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional media sensors are used to detect media presence and position, then basic media monitoring is achieved, but media jam detection is inefficient and requires physical disassembly
Solution Approach 1:
The sensor unit is positioned upstream or at the location where media jams are likely to occur, enabling detection before the jam fully develops. This allows the system to take preliminary action by stopping media supply before the jam worsens, making the clearing process easier and faster.
Solution Approach 2:
A tab is introduced as an intermediary element that physically moves the sensor unit into contact with the media roll surface. This intermediary mechanism enables the sensor to detect jams through indirect contact, improving detection accuracy while keeping the sensor unit separate from the main media path until needed.
2Loss of time
If no proactive jam detection is implemented, then the printer structure remains simple, but media jams cause significant downtime and user effort
Solution Approach 1:
The sensor unit is designed to be self-positioning through the tab mechanism that moves it into contact with the media roll. This self-service approach reduces the need for complex mounting structures and external adjustment mechanisms, minimizing added complexity while enabling proactive jam detection.
Solution Approach 2:
The patent replaces complex mechanical jam detection mechanisms with an optical or electromagnetic sensor unit. Instead of using mechanical switches or physical contact sensors that require complex linkages, the system uses light-based or field-based sensing to detect media jams, reducing mechanical complexity.
3Measurement precision
If the sensor unit is positioned close to the roller for accurate detection, then jam detection precision improves, but the sensor may be affected by media surface variations
Solution Approach 1:
The sensor unit is segmented into separate functional components: the tab for positioning, the sensor element for detection, and the signal processing unit. This segmentation allows each component to be optimized independently - the tab handles positioning while the sensor focuses on precise reflectance measurement, reducing interference from media surface variations.
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
Enables rapid detection of media jams, preventing further obstruction and simplifying the clearing process by stopping media supply, thus reducing user effort and printer downtime.
Implementation Method 1
The light detector is configured to detect reflected light from the surface of the roller in response to the incident light
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
Various embodiments disclose a method of detecting a media jam in a printer. The method includes causing a sensor unit of the printer to generate a sensor signal indicative of a reflectance characteristic associated with a surface of a roller of the printer. Further, the method includes receiving the sensor signal from the sensor unit of the printer and comparing the reflectance characteristic to a threshold reflectance characteristic associated with the roller. Furthermore, in response to the comparison, the method includes generating an output signal to indicate whether the media jam has occurred. For example, a first output signal indicates unsuccessful passage of a media along a media path of the printer, when the reflectance characteristic exceeds the threshold reflectance characteristic and a second output signal indicates successful passage of the media along the media path, when the reflectance characteristic is equal to or below the threshold reflectance characteristic.