Image Forming Apparatus Light Exposure Control for Film Thickness
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face challenges in determining optimum light exposure conditions suitable for both charging potential and film thickness of the image bearing member, leading to fluctuations in halftone image density due to changes in photo-induced discharge characteristics and film thickness over time.
Innovation Solution
An image forming apparatus comprising a charger unit, light exposure unit, developer unit, detection unit, and control units that calculate and adjust light exposure conditions based on estimated film thickness and target charging potentials, allowing for continuous image formation without the need for forming reference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference patterns of latent images are formed on the photoreceptor surface to determine optimum light exposure amount, then the light exposure amount can be accurately adjusted based on potential measurement, but another image formation cannot be carried out over the period from initiating to completing the determination of optimum light exposure amount
Solution Approach 1:
The patent pre-calculates and stores the relationship between film thickness and optimum light exposure amount in a table before actual operation. During image formation, the system only needs to estimate current film thickness and retrieve the corresponding light exposure amount from the pre-prepared table, eliminating the need to form reference patterns and perform potential measurements during production.
2Productivity
If discrete thickness values are stored in data storage unit with corresponding reference light exposure amounts, then the optimum light exposure amount can be read out without forming reference patterns, but the change in light exposure is not feasible during the change from one thickness value to another
Solution Approach 1:
The patent transitions from static discrete thickness values to a dynamic continuous calculation model. Instead of storing fixed reference values for specific thicknesses, the system uses a calculation formula that takes film thickness as input and outputs the corresponding light exposure amount. This allows the light exposure amount to be dynamically adjusted for any film thickness value, not just predefined discrete points.
Solution Approach 2:
The patent changes the approach from storing fixed parameter values (discrete thickness-light exposure pairs) to using a calculation formula where parameters (film thickness) can vary continuously. The formula L = f(t) enables the light exposure amount L to be calculated for any film thickness t, providing continuous adaptability rather than discrete steps.
3Device complexity
If the thickness of image bearing member is estimated from rotation and operating hours to determine light exposure amount, then reference patterns need not be formed, but the determination of optimum light exposure conditions suitable for both charging potential and film thickness is insufficient
Solution Approach 1:
The patent extends the calculation formula to incorporate multiple parameters: film thickness t, uniform charging potential Vd, and light exposure amount L. The formula L = f(t, Vd) allows the system to calculate appropriate light exposure amounts that are suitable for both the current film thickness and charging potential conditions, providing comprehensive and accurate light exposure control.
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 solution enables the determination of optimum light exposure conditions suitable for both charging potential and film thickness, maintaining excellent image densities even after film thickness decrease and uniform charging potential changes, and allows for continuous image formation during the setting of light exposure conditions.
Implementation Method 1
photo-induced discharge characteristics change with the abovementioned fluctuations
Data Source
AI summary
An image forming apparatus, incorporating a process cartridge, capable of determining optimum light exposure conditions suitable for both a charging potential and a film thickness of image bearing member, and performing the image formation even during the period from initiating to completing the setting of light exposure conditions. The image forming apparatus includes at least a charger unit, a light exposure unit, a developer unit, a detection unit, and a control unit. The detection unit is adapted to detect the total of rotation of the image bearing member. The control unit computes light exposure conditions to operate the light exposure unit based on an estimated thickness for a film of the image bearing member, which is calculated from the total of rotation obtained by the detection unit, and a first target uniform charging potential to control a uniform charging potential of the image bearing member, and to control the light exposure unit to be brought into the light exposure conditions.