Image Forming Apparatus Development Contrast Control
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Solution Overview
Problem
Increasing the peripheral velocity ratio between a photosensitive drum and a developing roller in image forming apparatuses can lead to higher image density, making the dot pattern intended for identification visible, compromising image quality.
Innovation Solution
Implementing a system that adjusts the peripheral velocity ratio to maintain a higher ratio while controlling toner supply and exposure to ensure the dot pattern remains invisible, even in wide-color gamut image formation modes, by reducing the contrast and toner volume level of the traceable pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the peripheral velocity ratio between the photosensitive drum and the developing roller is increased to enhance color gamut and image density, then the image quality is improved, but the dot pattern intended for identification becomes visible
Solution Approach 1:
The patent applies different development contrasts to different regions of the image. Specifically, it uses a first development contrast for the main image area and a second development contrast (lower than the first) for the dot pattern area. This local differentiation allows the main image to achieve high density while the dot pattern remains invisible, resolving the contradiction between image quality enhancement and dot pattern visibility.
Solution Approach 2:
The patent dynamically changes the development contrast parameter based on the imaging mode. In wide-color-gamut image formation mode, it reduces the development contrast specifically for the dot pattern area while maintaining high peripheral velocity ratio. This parameter adjustment ensures that even with increased peripheral velocity ratio that enhances overall image density, the dot pattern density remains controlled and invisible.
2Manufacturing precision
If the peripheral velocity of the photosensitive drum is reduced to increase the peripheral velocity difference and suppress toner scattering, then image quality is improved, but the throughput speed decreases
Solution Approach 1:
The patent dynamically adjusts the peripheral velocity of the photosensitive drum based on the imaging mode. In wide-color-gamut mode, it reduces the peripheral velocity to increase the peripheral velocity difference between the photosensitive drum and developing roller, which suppresses toner scattering and improves image quality. In standard mode, it maintains higher peripheral velocity for faster throughput. This dynamic adjustment resolves the contradiction between toner scattering control and production speed.
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
Enables the formation of high-quality images with enhanced color gamut while preventing the traceable pattern from becoming visible, ensuring consistent image quality and identification security.
Implementation Method 1
an electrostatic latent image is formed on a surface of a photosensitive drum in the plurality of image forming stations
Implementation Method 2
The electrostatic latent image formed on the photosensitive drum is developed by a developing apparatus as a toner image
Data Source
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AI summary
In a first image formation mode, an image is formed with a first development contrast C1 and a specific dot pattern is formed with a second development contrast C2, which is lower than the first development contrast C1; in a second image formation mode, an image is formed with a third development contrast C3 and a specific dot pattern is formed with a fourth development contrast C4, which is lower than the third development contrast C3; and when ΔC1 (= C2/C1) denotes a ratio between the second development contrast C2 and the first development contrast C1, and ΔC2 (= C4/C3) denotes a ratio between the fourth development contrast C4 and the third development contrast C3, ΔC2 < ΔC1 is satisfied.