Toner Charging State Detection via Density Sensing
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Solution Overview
Problem
In image forming apparatuses using electrophotography, a toner charging amount that falls outside an appropriate range can lead to transfer failures of monochrome toner images from photoconductors to an intermediate transfer member and subsequently to the sheet, due to variations in toner charging states.
Innovation Solution
A toner charging state determination method that involves transferring test toner images onto an intermediate transfer member, stopping and supplying secondary transfer voltage at specific points, and sensing toner densities to determine the toner charging state by comparing first and second sensing densities, allowing for adjustments in primary transfer voltage to maintain optimal toner charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the toner charging amount is increased to improve transfer efficiency, then the transfer speed increases, but the toner charging state becomes unstable and transfer failures occur
Solution Approach 1:
The patent implements a feedback mechanism where the density sensing portion detects toner density on the intermediate transfer member, and the control portion adjusts the primary transfer voltage based on the detected density to maintain optimal toner charging state. This closed-loop control ensures transfer stability while maintaining efficiency.
Solution Approach 2:
The patent dynamically changes the primary transfer voltage parameter based on detected toner density to optimize the toner charging state. By adjusting this electrical parameter, the system maintains reliable transfer without requiring excessive toner charging amounts.
2Loss of substance
If the toner charging amount is decreased to reduce waste, then material consumption decreases, but transfer failures occur due to insufficient charging
Solution Approach 1:
The density sensing portion provides real-time feedback on toner density, allowing the control portion to precisely adjust the primary transfer voltage. This ensures the minimum necessary toner charging is applied, reducing waste while preventing transfer failures.
Solution Approach 2:
The system dynamically adjusts the primary transfer voltage based on actual toner density conditions rather than using a fixed charging amount. This dynamic adaptation optimizes toner usage by applying only the necessary charging level for successful transfer.
3Measurement precision
If a complex sensing system is used to accurately determine toner charging state, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent uses the intermediate transfer member as an intermediary to enable density sensing. The density sensing portion detects toner density on the intermediate transfer member, which indirectly provides information about the toner charging state from the photoconductors, simplifying the overall measurement system.
Solution Approach 2:
The patent replaces direct mechanical or electrical sensing of toner charging on photoconductors with optical density sensing on the intermediate transfer member. This substitution simplifies the sensing mechanism while maintaining measurement precision.
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 effectively determines the toner charging state, preventing transfer failures by ensuring the toner charging amount remains within the appropriate range, thereby ensuring reliable image formation.
Implementation Method 1
the image forming apparatus transfers the plurality of monochrome toner images respectively formed on the surfaces of the plurality of photoconductors onto a surface of an intermediate transfer member by an electrostatic force
Implementation Method 2
the image forming apparatus transfers the synthetic toner image formed on the surface of the intermediate transfer member onto a sheet by an electrostatic force
Data Source
AI summary
A processor causes a printing portion to execute test image transfer processing for transferring a plurality of test toner images onto an area outside a secondary transfer area on a surface of an intermediate transfer member, and secondary voltage stop processing for stopping a supply of a secondary transfer voltage. The processor acquires a plurality of first sensing densities. The processor causes the printing portion to execute the test image transfer processing and secondary voltage supply processing for supplying the secondary transfer voltage. The processor acquires a plurality of second sensing densities. The processor compares the plurality of first sensing densities and the plurality of second sensing densities to determine a state of a toner charging amount in each of the plurality of test toner images.