Image Forming Apparatus Bias Voltage Determination
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Solution Overview
Problem
Conventional image forming apparatuses fail to accurately determine target bias voltage values due to variations in the slope defined by the correlation between bias voltage and density, leading to suboptimal toner image formation.
Innovation Solution
An image forming apparatus that applies test bias voltage values to form marks on an image holding member, detects their densities, calculates the slope, and determines the target bias voltage value based on these measurements, thereby accounting for variations in the slope and ensuring precise toner image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional image forming apparatus uses a fixed correlation between bias voltage and density to determine target bias voltage value, then the determination process is simple, but the accuracy deteriorates due to degradation of toner or image holding member
Solution Approach 1:
The apparatus performs preliminary testing by forming marks at multiple positions on the image holding member and measuring their densities before determining the target bias voltage value. This preliminary measurement of the actual correlation between bias voltage and density allows the system to account for degradation effects and adjust the target bias voltage accordingly, improving accuracy without requiring complex real-time adjustments during normal operation.
2Measurement precision
If the apparatus forms marks at multiple positions and measures densities to account for slope variation, then the accuracy of target bias voltage determination improves, but the measurement time increases
Solution Approach 1:
The density measurement of marks is performed as a preliminary action before the actual image formation process. By pre-measuring the densities of marks formed at multiple positions with different bias voltages, the system establishes the actual correlation curve in advance, allowing for rapid determination of the target bias voltage without repeating the measurement process during normal operation.
Solution Approach 2:
The system uses the measured density data from the preliminary marks to automatically determine the target bias voltage value through calculation. The controller processes the measured densities and corresponding bias voltages to compute the actual correlation, then uses this correlation to self-determine the optimal target bias voltage, eliminating the need for manual intervention or repeated measurements.
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 allows for the determination of target bias voltage values that suppress the influence of slope variations, resulting in improved toner image quality and stability by adjusting bias voltage settings dynamically.
Implementation Method 1
a developing portion, and configured to apply a developing bias voltage to the developing portion to develop an electrostatic latent image on the image holding member
Implementation Method 2
a sensor configured to detect a mark formed as the toner image by the forming section
Data Source
AI summary
There is provided an image forming apparatus including: a forming section having an image holding member and an developing portion, and configured to apply a developing bias voltage to the developing portion to develop an electrostatic latent image on the image holding member; a sensor configured to detect a mark formed by the forming section; a storage; and a controller configured to perform: forming first and second marks, obtaining the densities of the first and second marks, obtaining a slope, and determining a target bias voltage value, and storing the target bias voltage value in the storage.