Reflective Sensor for Ink Contamination Detection on Decurler Rollers
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Solution Overview
Problem
Inkjet printers using aqueous inks often experience media deformation and curling issues due to ink absorption, leading to unacceptable levels of curl in printed sheets, which can cause wrinkling and require frequent maintenance to prevent sheet damage.
Innovation Solution
A decurler system with an indent roller and elastomeric roller, equipped with a reflective sensor to detect ink adherence on the indent roller, uses a light emitter and receiver to generate a signal indicative of specular reflection, allowing the controller to compare the signal magnitude to a threshold and trigger maintenance alerts before ink accumulation causes wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the decurler operates continuously to counteract media curl, then media flatness is improved, but ink accumulates on the indent roller causing wrinkling
Solution Approach 1:
The reflective sensor detects ink accumulation on the indent roller before it reaches levels that cause media wrinkling. By monitoring the specular reflection properties of the roller surface continuously, the system performs preliminary detection and triggers maintenance alerts in advance, preventing the harmful effect of wrinkling before it occurs.
2Reliability
If maintenance is performed frequently to remove ink from the indent roller, then media quality is improved, but printer downtime increases
Solution Approach 1:
The system implements continuous feedback monitoring using the reflective sensor to track ink accumulation on the indent roller. The controller receives real-time signals from the sensor and compares them against threshold values, enabling condition-based maintenance scheduling. This feedback mechanism allows maintenance to be performed only when necessary, optimizing the balance between media quality and printer utilization.
Solution Approach 2:
The decurler system performs self-monitoring through the reflective sensor and controller, which automatically detect ink accumulation levels and generate maintenance alerts without requiring manual inspection. This self-service capability enables operators to schedule maintenance during planned downtime rather than performing frequent preventive maintenance, reducing overall printer downtime.
3Shape
If the indent roller contacts the printed media to induce opposite curl, then curl control is improved, but ink adheres to the roller surface
Solution Approach 1:
The reflective sensor acts as an intermediary monitoring device that indirectly measures ink accumulation on the indent roller by detecting changes in the roller's surface reflectivity. This intermediary measurement approach allows the system to track ink buildup without interfering with the decurling function, maintaining curl control while enabling detection of the harmful ink accumulation.
Solution Approach 2:
The system utilizes optical property changes (specular reflection) of the indent roller surface as ink accumulates on it. Fresh ink on the roller surface alters the way light reflects from the roller, and the reflective sensor detects these optical changes. This principle allows non-contact detection of ink accumulation while the roller continues to perform its decurling function.
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
The system effectively detects and alerts for ink accumulation on the indent roller, preventing wrinkling and ensuring smooth operation by allowing for timely maintenance, thus maintaining the quality of printed sheets.
Implementation Method 1
a light receiver that is oriented to receive specular reflections of the light directed onto the surface of the indent roller
Data Source
AI summary
A decurler is configured for use in an aqueous inkjet printer to monitor ink contamination of the indent roller in the decurler and generate a signal that maintenance is required prior to the printer beginning to produce wrinkled media sheets by the ink contamination on the indent roller. A reflective sensor is mounted on a shaft for bidirectional movement to sweep the length of the indent roller and generate electrical signals indicative of the presence or absence of contamination on the indent roller. The controller receiving signals from the reflective sensor compares the signals from the reflective sensor to a predetermined threshold prior to commencing monitoring of the indent roller to determine positions where the sensor is opposite the indent roller and positons where the sensor is opposite a frame in the printer.