Image Forming Apparatus Density Control for Color Gamut Modes
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Solution Overview
Problem
Existing image forming apparatuses with multiple modes face errors in calculating density for low density regions due to extrapolation from high density measurements, leading to increased errors as input image data deviates from standard modes.
Innovation Solution
An image forming apparatus that operates in two color gamut modes, using a photosensitive drum, exposure unit, developing roller, intermediate transfer member, density detection unit, and controller, where the dithering process adjusts based on mode, ensuring higher density in low density regions for the first mode compared to the second mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If density in other image forming modes is calculated by arithmetic processing from measured density information in standard mode, then tinge can be adjusted without additional downtime, but error increases in low density portions
Solution Approach 1:
The patent performs preliminary density measurement in the standard image forming mode before switching to other modes. By measuring density in the standard mode first and then calculating density in other modes through arithmetic processing, the system avoids additional measurement downtime while obtaining necessary density data for tinge adjustment in different modes
Solution Approach 2:
The patent changes the parameter being measured by selecting different measurement regions. Instead of measuring low density portions directly in other modes (which causes errors), it measures high density portions in the standard mode where measurement is more accurate, then uses parameter transformation to derive the corresponding density values for other modes
2Productivity
If extrapolation is used to calculate low density portion from high density portion result, then calculation can be performed without additional measurement, but error increases as image data departs from calculation point
Solution Approach 1:
The patent creates a reference model by measuring density in the standard image forming mode, then copies and adapts this reference data for use in other image forming modes through arithmetic processing. This allows the system to leverage accurate reference measurements rather than relying on error-prone extrapolation from limited data points
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 reduces errors in low density region calculations, maintaining accurate image formation without increasing downtime by adjusting toner image density based on input data, thereby improving color gamut performance.
Implementation Method 1
an exposure unit that forms an electrostatic latent image by exposing the photosensitive drum
Implementation Method 2
a developing roller that forms a toner image by developing the electrostatic latent image which is formed using a toner on the photosensitive drum
Data Source
AI summary
An image forming apparatus, configured to operate in first and second modes of which color gamut is different from each other, includes an exposure unit configured to expose a photosensitive drum; a developing roller configured to form a toner image; a detection unit configured to detect density of the toner image transferred to an intermediate transfer member; and a controller configured to adjust the density based on a value of input image data. A dithering process for the controller's controlling of the exposure unit is different depending on whether the operation is in the first mode or the second mode, and in at least a part of the input image data, the density of the toner image formed by the dithering process in the first mode is higher than the density of the toner image formed by the dithering process in the second mode.