Successive White Toner Image Formation for Dark Paper
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Solution Overview
Problem
In electrophotographic image forming apparatuses, forming images with a high hiding rate on dark-colored paper using white toner is challenging due to potential image defects like toner fog and positional displacement when increasing toner amounts, limiting productivity.
Innovation Solution
The apparatus employs multiple image forming units, including at least two units for special colors like white toner, arranged in succession to increase the total toner amount without defects, with a controller managing the process to ensure accurate toner distribution and fixing temperature adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the toner amount of white toner is increased to improve hiding rate on dark-colored paper, then the hiding rate is improved, but image defects such as toner fog occur
Solution Approach 1:
The patent divides the image formation process into multiple sequential steps using multiple image forming units. Instead of forming a single white image with excessive toner that causes fog, the system forms multiple images with controlled toner amounts in succession, where each image forming unit contributes a portion of the total toner. This segmentation allows the cumulative toner amount to be increased while maintaining image quality in each individual step.
Solution Approach 2:
The patent employs multiple image forming units that operate in continuous succession to form multiple white images one after another. This continuous process allows the toner amount to be accumulated progressively across multiple images rather than attempting to deposit all toner in a single step, thereby avoiding toner fog while achieving the desired high hiding rate.
2Quantity of substance
If the toner amount is increased by overprinting multiple white images, then the hiding rate is improved, but positional displacement occurs and productivity decreases
Solution Approach 1:
The patent merges the functions of multiple image forming units into a single integrated process. Multiple white images are formed in succession on the same recording medium without requiring separate handling or positioning operations between each image formation step. This merging of operations eliminates positional displacement issues while maintaining high productivity through automated sequential processing.
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 configuration allows for a significant increase in white toner amount without image defects, maintaining the original tint of basic color toners and improving productivity by ensuring accurate toner placement and fixing properties.
Implementation Method 1
a photoconductor drum 16, a charging device 18, a developing device 20, and a cleaning device 22
Implementation Method 2
an optical scanning device 24 that scans and irradiates the photoconductor drum 16 with a laser beam
Implementation Method 3
a developing device 20 that develops the electrostatic latent image with toner
Implementation Method 4
a secondary transfer device 34 that transfers the toner image, which is formed on the intermediate transfer belt 14, onto the recording medium
Implementation Method 5
a fixing device 36 that fixes the toner image, which is transferred onto the recording medium
Data Source
AI summary
An image forming apparatus includes plural image forming units and a controller. The plural image forming units are configured to form images of colors using colorants, respectively. The controller is configured to perform control such that the plural images formed by the plural image forming units are output as one image onto a recording medium. At least two of the image forming units are configured to form images using colorants of special colors, respectively and are arranged in succession.