Development Voltage Calibration for Photosensitive Layer Wear
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Solution Overview
Problem
In image forming apparatuses using two-component developer, the thickness of the photosensitive layer affects development characteristics, leading to decreased toner transfer and potential white dots on the image due to high development voltage, while maintaining a thick layer is necessary for longevity.
Innovation Solution
An image forming apparatus with a layer thickness detection mechanism adjusts the upper limit of the DC voltage based on the photosensitive layer thickness, using a control unit to calibrate and superimpose AC voltage on the DC voltage, ensuring appropriate image density and preventing white dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the development voltage is increased to improve toner transfer for thick photosensitive layers, then developability is improved, but white dots occur due to toner aggregate transfer
Solution Approach 1:
The patent applies dynamics by making the development voltage adaptive rather than fixed. The control unit dynamically adjusts the development voltage based on real-time detection of photosensitive layer thickness. When the layer is thick, higher voltage is applied to ensure adequate toner transfer; when thin, lower voltage prevents toner aggregate transfer and white dots. This dynamic adjustment resolves the contradiction between maintaining developability and preventing defects.
Solution Approach 2:
The patent changes the parameter of development voltage based on the detected thickness of the photosensitive layer. The control unit modifies the voltage parameter in response to varying layer conditions, optimizing toner transfer while preventing white dot formation. This parameter adaptation directly addresses the technical contradiction by tailoring the voltage level to the specific layer thickness condition.
2Duration of action of stationary object
If a thick photosensitive layer is used to extend apparatus lifespan, then durability is improved, but toner transfer decreases due to increased capacitance
Solution Approach 1:
The patent implements feedback by using a detection mechanism to monitor photosensitive layer thickness and using this information to adjust the development voltage. The control unit receives feedback about the layer condition and modifies the voltage accordingly. This feedback loop enables the system to maintain optimal toner transfer performance throughout the apparatus lifespan, even as the photosensitive layer degrades over time.
Solution Approach 2:
The system transitions from a static voltage approach to a dynamic one where the development voltage automatically adapts to the current state of the photosensitive layer. As the layer thickness changes during the apparatus operational life, the voltage is dynamically adjusted to compensate, ensuring consistent toner transfer performance while maintaining the benefit of using thicker layers for durability.
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 solution effectively maintains image density and prevents white dots by dynamically adjusting the DC voltage limit, accommodating varying photosensitive layer thickness and humidity conditions, thus extending the apparatus' lifespan.
Implementation Method 1
The development voltage power supply applies a development voltage, in which an AC voltage is superimposed on a DC voltage, to the developer carrier
Implementation Method 2
The exposure device exposes the surface of the image carrier charged by the charging device, so as to form an electrostatic latent image whose charge is attenuated
Implementation Method 3
The charging device charges the surface of the image carrier
Implementation Method 4
The development device includes a developer carrier that carries developer containing the toner, so as to develop an electrostatic latent image formed on the image carrier into a toner image
Data Source
AI summary
An image forming apparatus includes an image forming unit having an image carrier, a charging device, and a development device, so as to perform image formation using toner, an exposure device, an image density sensor, a development voltage power supply, a control unit, and a layer thickness detection mechanism. The control unit can perform calibration, in which density of a reference image formed by the image forming unit is detected by the image density sensor, and the development voltage is adjusted based on a detection result, so as to adjust the density of the toner image. The layer thickness detection mechanism detects thickness of the photosensitive layer. Along with a decrease in the thickness of the photosensitive layer detected by the layer thickness detection mechanism, the control unit stepwisely decreases an upper limit value of the DC voltage from a reference value, when adjusting the development voltage in the calibration.