Tandem Image Formation Density Control via Inter-Apparatus Feedback
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Solution Overview
Problem
In tandem-type electrophotographic image formation systems, differences in output performances of IDC sensors between upstream and downstream image forming apparatuses lead to inconsistent image densities on the front and rear surfaces of sheets, resulting in varying image quality and toner consumption disparities.
Innovation Solution
The system includes a first and second image forming apparatus, a sheet inversion section, and an inter-apparatus density adjusting section, where image density detection is performed on both surfaces, and light exposure energies are corrected based on detected patterns to stabilize image densities across both surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If image density control is performed independently in each image forming apparatus using their own IDC sensors, then each apparatus can maintain its own image density, but density differences occur between front and rear surfaces due to sensor output performance variations
Solution Approach 1:
The system uses an inter-apparatus density adjustment mechanism that incorporates feedback from density detection sections to continuously monitor and adjust the density control points of both image forming apparatuses. This feedback loop ensures that density differences between front and rear surfaces are detected and corrected, maintaining consistent image quality across the entire sheet while allowing each apparatus to operate independently.
2Manufacturing precision
If density control points are adjusted to compensate for sensor output differences, then initial density consistency is achieved, but gradual density differences develop over time due to changing development performance
Solution Approach 1:
The system performs preliminary adjustments by detecting pattern images with highest density and half-tone density before actual image formation. These preliminary density measurements are used to pre-calculate and set appropriate density control points for both apparatuses, anticipating and preventing gradual density differences that would develop during continuous operation with two-component developers.
Solution Approach 2:
The density detection section continuously monitors image density during operation and provides feedback to the control system. This ongoing feedback enables real-time adjustment of density control parameters, compensating for gradual changes in development performance and maintaining density consistency throughout the entire imaging process and over extended operation periods.
3Ease of operation
If the same density control point is used in both apparatuses, then operational simplicity is maintained, but density differences between front and rear surfaces result from varying sensor performances
Solution Approach 1:
The system applies different density control points to each image forming apparatus based on their specific sensor output performances and characteristics. Rather than using a uniform control point for both apparatuses, the system tailors individualized control parameters to each apparatus's specific performance characteristics, ensuring optimal density consistency while maintaining relatively simple operational procedures through automated adjustment.
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 ensures consistent image density on both surfaces of the sheet, preventing gradual density differences and maintaining stable image quality, even with two-component developers, by adjusting density control points and light exposure energies according to coverage rates.
Implementation Method 1
irradiate (expose) a uniformly-charged photoconductor (for example, a photoconductor drum) with (to) light based on image data to form an electrostatic latent image on the surface of the photoconductor
Implementation Method 2
a first charging section configured to charge a surface of the first photoconductor
Implementation Method 3
a first development section configured to supply developer to visualize the electrostatic latent image
Implementation Method 4
followed by heating and pressurization for fixing, whereby an image is formed on the sheet
Data Source
AI summary
An image formation system includes: a first image forming apparatus; a sheet inversion section; a second image forming apparatus; an image density detection section configured to detect a density of a first pattern image for a highest density adjustment and a density of a second pattern image for a half-tone density adjustment, each of the first and second pattern images being formed on a sheet in each of the first image forming apparatus and the second image forming apparatus; and an inter-apparatus density adjusting section. The inter-apparatus density adjusting section corrects a density control point and a light exposure energy on a basis of detection results of the first and second pattern images of the image density detection section, respectively. The first and second density control sections correct the density control point or the light exposure energy in accordance with a coverage rate of an image.