Image Density Correction for Electrophotographic Printers
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Solution Overview
Problem
Existing image forming apparatuses using electrophotographic processes face challenges in maintaining high printing efficiency while effectively suppressing color fluctuations during continuous printing, as prior methods fail to accurately correct developing characteristics, leading to potential image quality issues.
Innovation Solution
An image density correction method that forms patch images at varying developing biases, calculates actual toner amounts, and adjusts developing biases based on relational characteristics to align with reference toner amounts, ensuring high-quality images even with large color fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If frequent calibration is performed to correct color fluctuations, then image quality is improved, but printing efficiency deteriorates due to repeated halts
Solution Approach 1:
The system performs preliminary calibration before continuous printing to establish baseline developing biases. During continuous printing, it continuously monitors patch image densities and automatically adjusts developing biases in real-time without halting printing, thus maintaining image quality while preserving printing efficiency.
Solution Approach 2:
The system incorporates continuous feedback by detecting patch image densities during printing and automatically adjusting developing biases based on deviations from ideal densities. This closed-loop control enables real-time color correction without manual intervention or printing halts, resolving the contradiction between image quality maintenance and printing efficiency.
2Manufacturing precision
If patch images are formed at multiple density levels to correct developing characteristics, then color accuracy is improved, but device complexity increases
Solution Approach 1:
The system forms patch images at multiple density levels (e.g., 30%, 50%, 70%) in specific regions of the image supporter to locally characterize developing characteristics. This targeted approach at multiple density points enables comprehensive color correction while avoiding the complexity of uniformly testing all regions, thus improving color accuracy with manageable system complexity.
3Manufacturing precision
If continuous monitoring and adjustment of developing biases is performed, then color fluctuations are suppressed, but processing time increases
Solution Approach 1:
The system continuously monitors patch image densities and adjusts developing biases throughout the printing process without interruption. This continuous action ensures color consistency is maintained throughout printing, and the adjustments are made incrementally to minimize processing time overhead, resolving the contradiction between color consistency and processing time.
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
This method allows for high-quality image formation by suppressing color fluctuations while maintaining high printing efficiency, even during continuous printing, by dynamically adjusting developing biases to match reference toner amounts.
Implementation Method 1
a developing section 34 supplied with a developing bias voltage from the developing bias setting section 95, a fusing section 40... The developing section 34 includes a toner box 341 storing toner of black (B)
Implementation Method 2
a fusing section 40... The fusing section 40 includes a heating roller 42 housing a heater 421 and a pressure roller 43
Data Source
AI summary
In an image density correction method in accordance with an embodiment of the present invention, an image density correction is carried out by obtaining an actual toner amount through obtaining a density of a between-sheet patch image having been formed during continuous printing, reconstructing relational characteristics in which the actual toner amount is associated with each variation in developing biases, by considering that the actual toner amount and a reference toner amount are to be made in agreement, when a determination that the actual toner amount disagrees with the reference toner amount is made, and resetting a developing bias for realizing the reference toner amount based on the reconstructed relational characteristics and the reference toner amount. By this means, a high quality image can be obtained by suppressing color fluctuations with printing efficiency maintained at a high level even if large color fluctuations occur during continuous printing.