Print Roller Voltage Profile Control for Optical Density Uniformity
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Solution Overview
Problem
In printing processes, non-uniformity in ink application leads to defects such as banding and color inconsistencies, making it difficult to diagnose and rectify issues, resulting in wasted time and potential misdiagnosis of faults.
Innovation Solution
A method involving the control of a print apparatus roller voltage to compensate for color non-uniformity by varying the potential difference during the transfer of print agent, using a first voltage profile to detect consistent variations in optical density across printed images and adjusting to a second voltage profile to address these variations, thereby improving color uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a constant voltage profile is used during print agent transfer, then the printing process is simple and stable, but color non-uniformity and banding defects occur
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static constant voltage profile to a dynamic variable voltage profile. The voltage applied to the transfer roller is continuously adjusted during the transfer cycle based on detected optical density variations, allowing the system to adapt to changing conditions and compensate for non-uniformities in real-time, thereby improving color uniformity without excessive complexity.
Solution Approach 2:
The patent implements parameter changes by modifying the voltage parameter of the transfer roller. Instead of maintaining a fixed voltage, the system varies the voltage level dynamically during the transfer process based on measured optical density variations. This parameter adjustment allows compensation for non-uniform print agent transfer and eliminates banding defects while maintaining manageable system complexity through automated control.
2Reliability
If print agent transfer is performed without voltage compensation, then the printing process is fast and simple, but optical density variations and banding defects occur
Solution Approach 1:
The patent applies feedback by implementing a closed-loop control system where optical density of transferred print agent is continuously measured and used to adjust the voltage profile. The system detects variations in optical density during transfer and feeds this information back to modify the voltage applied to the transfer roller, ensuring consistent print quality and enabling rapid identification and correction of issues without time-consuming manual diagnosis.
Solution Approach 2:
The patent implements preliminary action by proactively compensating for optical density variations through real-time voltage adjustment during the transfer process. Rather than detecting defects after printing and then diagnosing issues, the system performs preliminary correction by adjusting voltage parameters during transfer itself, preventing banding defects before they occur and maintaining reliable print quality consistency.
3Manufacturing precision
If voltage profile is adjusted to compensate for optical density variations, then color uniformity improves, but the control system becomes more complex
Solution Approach 1:
The patent applies self-service by implementing an automated voltage control system that self-adjusts based on real-time optical density measurements. The system monitors its own transfer process, detects variations in optical density, and automatically modifies the voltage profile without requiring external intervention or complex manual calibration. This self-regulating mechanism achieves high optical density uniformity while keeping the control system manageable through automation rather than manual complexity.
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 method effectively compensates for consistent optical density variations, reducing banding defects and improving color uniformity across printed images, thereby streamlining defect diagnosis and maintenance.
Implementation Method 1
transferring print agent between a roller of a print agent source and an electrophotographic surface in a print agent transfer operation, wherein the roller is controlled to have a (common) first voltage profile during each of the transfer operations
Data Source
AI summary
In an example, a method includes printing a set of images by transferring print agent between a roller of a print agent source and an electrophotographic surface in a plurality of transfer operations, wherein the roller is controlled to have a first voltage profile during each of the transfer operations. A variation in optical density which is consistent across the set of printed images may be detected, and a second voltage profile correction may be determined based on the variation in optical density. The method may further comprise printing a subsequent image by transferring print agent between the print agent source roller and the electrophotographic surface in a subsequent transfer operation, wherein the roller is controlled to have the second voltage profile during the subsequent transfer operation.