Developing Device Toner Charging Peeling Current Measurement
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Solution Overview
Problem
In electrophotographic image forming apparatuses, existing developing devices face challenges in distinguishing between changes in toner charging amount and toner peeling amount due to surface wear of the supply roller, leading to inaccurate deterioration detection and process control.
Innovation Solution
A developing device with first and second current measuring portions to measure currents in the developing and supply rollers, respectively, and a control portion to calculate toner charging and peeling amounts, allowing for accurate process control and deterioration detection by applying bias voltages and using a toner layer regulation blade with insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only the current flowing between the developing roller and the supply roller is measured, then the measurement system remains simple, but it becomes impossible to distinguish between changes in toner charging amount and toner peeling amount
Solution Approach 1:
The patent divides the single current measurement into two separate measurements: one for the current flowing in the developing roller and another for the current flowing in the supply roller. This segmentation allows independent calculation of toner charging amount and peeling amount, resolving the inability to distinguish between these two parameters while maintaining relatively simple measurement circuitry.
2Duration of action of stationary object
If the supply roller surface hardens due to massive printing, then the supply roller durability improves, but toner peeling fails and image quality deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the measured current values from the developing roller and supply roller are continuously monitored. When the calculated toner peeling amount falls outside the predetermined range, the system detects supply roller deterioration and issues a replacement notification, enabling timely maintenance before image quality deteriorates.
3Adaptability or versatility
If the toner charging amount changes due to toner variation, then the toner formulation flexibility improves, but the development stability deteriorates
Solution Approach 1:
By separately measuring currents in both rollers and calculating toner charging amount independently, the system can detect variations in toner properties. This feedback allows for real-time monitoring and adjustment, maintaining development stability even when toner formulations are varied or change over 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
Enables precise calculation of toner charging and peeling amounts, improving stability and preventing image failures by accurately detecting roller deterioration and adjusting image density, thus ensuring reliable operation of the developing device.
Implementation Method 1
a first current measuring portion which measures a value of a current flowing in the developing roller
Implementation Method 2
a second current measuring portion which measures a value of a current flowing in the supply roller
Implementation Method 3
a control portion which calculates a toner charging amount on the developing roller and a toner peeled amount by the supply roller based on measured results by the first current measuring portion and the second current measuring portion
Implementation Method 4
applies a bias voltage to the developing roller so as to develop an electrostatic latent image formed on the electrostatic latent image carrier with the toner
Data Source
AI summary
A developing device which includes a developing roller which supplies a toner to a photoreceptor and a supply roller which performs supply of a toner to the developing roller and peeling of a toner from the developing roller, and applies a bias voltage to the developing roller so as to develop an electrostatic latent image formed on the photoreceptor with a toner. The developing device includes a first current measuring portion which measures a value of a current flowing in the developing roller, a second current measuring portion which measures a value of a current flowing in the supply roller, and a control portion which calculates a toner charging amount on the developing roller and a toner peeled amount by the supply roller based on measured results by the first current measuring portion and the second current measuring portion.