Transfer Bias Control for Consistent Image Tone
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Solution Overview
Problem
In electrophotographic image forming apparatuses, achieving optimal transfer output for multi-color toner layers is challenging due to variations in toner amounts across pages, leading to inconsistent color tones or shades, especially when logo marks are present across multiple pages.
Innovation Solution
A control apparatus that specifies pages with similar image content and sets a uniform transfer bias within a predetermined range for all specified pages, ensuring consistent color tones or shades across pages with similar images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the transfer bias is optimized for each page based on total toner amount, then the transfer output quality is improved, but the consistency of color tones across pages with similar images deteriorates
Solution Approach 1:
The patent segments pages into two categories: pages with similar images (including logo marks) and pages without similar images. This segmentation allows different transfer bias control strategies to be applied to different page types, resolving the contradiction by treating similar pages uniformly while still optimizing for each segment's characteristics.
Solution Approach 2:
The patent applies local quality by using different transfer bias setting approaches for different page types. For pages with similar images, a uniform transfer bias within a predetermined range is applied to maintain consistency. For other pages, individual optimization based on total toner amount is permitted. This localized approach resolves the contradiction by adapting the control strategy to the specific characteristics of each page group.
2Stability of the object's composition
If a uniform transfer bias is applied to all pages, then the consistency of color tones is improved, but the optimization of transfer output for each page's specific toner amount deteriorates
Solution Approach 1:
The patent introduces dynamics by making the transfer bias control strategy adaptive rather than static. The system dynamically selects between two modes: uniform transfer bias for pages with similar images, and individualized transfer bias optimization for other pages. This dynamic adaptation resolves the contradiction by allowing the system to switch between consistency and optimization based on page characteristics.
3Productivity
If individual transfer bias optimization is performed for each page, then the transfer efficiency is improved, but the processing complexity and time for determining optimal values for each page increases
Solution Approach 1:
The patent applies preliminary action by pre-identifying and categorizing pages with similar images before the transfer process. This preliminary classification allows the system to apply uniform transfer bias settings to groups of similar pages, reducing the need for individual optimization calculations and thereby reducing processing complexity while maintaining transfer efficiency.
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 maintains consistent color tones or shades across pages, even when logo marks are present, by setting a single transfer bias value for pages with similar images, thereby reducing variations and enhancing image quality.
Implementation Method 1
a transfer device which transfers a toner image formed on an image carrier onto a medium
Data Source
AI summary
A control apparatus includes the following elements. A page specifying unit specifies, concerning image data representing images included in plural pages, among the plural pages, plural pages including images each having a similarity which is equal to or greater than a predetermined threshold. A controller controls a transfer bias to be applied to a transfer device which transfers a toner image formed on an image carrier onto a medium. The controller performs control, for the plural pages specified by the page specifying unit, such that each of values of the transfer bias to be applied to the transfer device when toner images corresponding to the plural pages specified by the page specifying unit are transferred onto the medium is within a predetermined range.