Toner Density Sensor Correction for Roller Contamination
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Solution Overview
Problem
Existing image-forming apparatuses face challenges in accurately measuring toner density on a belt-like moving medium due to foreign matter adhering to rollers, which affects sensor output and leads to misdetection, especially for toner patches with lower densities.
Innovation Solution
An image-forming apparatus with a density sensor opposite a roller, utilizing a non-toner area with a length equal to or greater than the roller's circumference to correct sensor outputs, thereby accounting for and reducing the impact of foreign matter on toner density measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a density sensor is disposed opposite a roller to measure toner density, then measurement capability is provided, but measurement precision deteriorates due to foreign matter adhering to the roller
Solution Approach 1:
The patent applies preliminary action by measuring sensor outputs in a non-toner area before the toner patch passes through the detection position. This allows the system to detect and compensate for foreign matter effects on the roller in advance, correcting the subsequent toner density measurements to maintain accuracy despite the presence of foreign matter.
Solution Approach 2:
The patent uses a non-toner area as an intermediary element to detect the impact of foreign matter on the roller. By measuring the sensor output in this intermediate zone where no toner is present, the system can isolate the foreign matter effect and use it to correct the toner patch measurements, effectively mediating between the harmful foreign matter and the measurement process.
2Measurement precision
If sensor output is used directly for toner density measurement, then measurement process is simple, but measurement precision deteriorates due to foreign matter impact
Solution Approach 1:
The system performs a preliminary measurement in the non-toner area to characterize the foreign matter effect before measuring the toner patch. This two-step process, while slightly more complex, enables accurate compensation and maintains high measurement precision by addressing the foreign matter impact proactively.
Solution Approach 2:
The patent implements feedback by using the sensor output from the non-toner area to correct the sensor output from the toner patch measurement. The foreign matter effect detected in the non-toner area is fed back into the measurement system to adjust and compensate for its impact on the toner density measurement, thereby maintaining precision despite the added complexity.
3Reliability
If no correction for foreign matter is applied, then measurement system is simple, but reliability deteriorates due to misdetection
Solution Approach 1:
The system performs preliminary measurement in the non-toner area to detect foreign matter effects before they impact the toner patch measurement. This advance detection allows for reliable compensation and correction, significantly improving measurement reliability by preventing misdetection caused by foreign matter, despite the added system complexity.
Solution Approach 2:
The patent uses feedback from the non-toner area measurement to correct the toner patch measurement. By continuously monitoring and compensating for foreign matter effects through this feedback mechanism, the system maintains high reliability in toner density measurements, ensuring accurate detection even in the presence of contaminating foreign matter.
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 approach enhances the accuracy of toner density measurement by correcting for misdetection caused by foreign matter, improving the reliability of toner density control and maintaining image quality.
Implementation Method 1
an optical sensor disposed opposite the sensor-opposite-roller, and detecting reflected light when the toner patch images of individual colors are irradiated with light
Data Source
AI summary
An image-forming apparatus includes an optical sensor including a light-receiving element that receives light reflected by a belt-like moving medium to produce an output corresponding to the amount of light received. This image-forming apparatus determines the density of a toner patch image formed by an image-forming unit by correcting an output produced when the optical sensor detects the toner patch image at a position on a roller disposed opposite the sensor on the basis of an output produced by the optical sensor in an area where no toner image is formed on the belt-like moving medium at the same position on the opposite roller as the position where the sensor detects the toner patch image.