Process Cartridge Toner Flow Path for Halftone Density Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face issues with toner circulation and density unevenness in halftone images due to inadequate recovery of residual toner on developing rollers, particularly in low-temperature and low-humidity environments, leading to image defects such as development ghosts and toner aggregation.
Innovation Solution
A process cartridge design with a developing chamber configuration where the developing roller and toner supplying roller have opposite movement directions, a controlled peripheral speed ratio (1.1≤R≤2.5), and specific toner and silica particle properties to ensure effective toner circulation and uniform coating, with a toner flow path distance of 1.0 mm to 5.0 mm and toner characteristics including average particle diameter, circularity, and silica content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developing roller and toner supplying roller move in the same direction with a peripheral speed difference, then high-speed printing is enabled, but residual toner is not sufficiently recovered in low-temperature and low-humidity environments, causing development ghosts and density unevenness
Solution Approach 1:
The patent inverts the conventional same-direction movement of rollers by making the developing roller and toner supplying roller move in opposite directions. This reversal ensures that the toner supplying roller effectively recovers residual toner from the developing roller even at high printing speeds, particularly in low-temperature and low-humidity environments where toner recovery is problematic with same-direction movement.
2Quantity of substance
If the developing roller and toner supplying roller are in contact with each other with a peripheral speed difference, then toner circulation is improved, but toner aggregation occurs in low-temperature and low-humidity environments, degrading coating properties
Solution Approach 1:
The patent applies opposite-direction movement of the developing roller and toner supplying roller to prevent toner aggregation while maintaining effective toner circulation. This configuration ensures uniform toner distribution on the developing roller surface even in low-temperature and low-humidity conditions where same-direction movement causes aggregation.
3Reliability
If the toner supplying roller recovers residual toner from the developing roller, then image quality is improved, but toner flow path design becomes more complex
Solution Approach 1:
The patent uses the opposite-direction movement of rollers to achieve effective toner recovery without requiring complex additional flow path designs. The inherent motion of the toner supplying roller in the opposite direction naturally facilitates toner recovery from the developing roller, simplifying the overall system design compared to same-direction configurations that would require additional mechanisms.
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
The solution ensures stable toner circulation and prevents density unevenness in halftone images, maintaining high-quality image output even in varying environmental conditions.
Implementation Method 1
a surface of the developing roller is in contact with a surface of the toner supplying roller, a movement direction of the surface of the developing roller is opposite to a movement direction of the surface of the toner supplying roller
Implementation Method 2
an electrophotographic photoreceptor (hereinafter, referred to as "photoreceptor") serving as an image carrying member is uniformly charged, and the charge photoreceptor is selectively exposed to light to form an electrostatic image on the photoreceptor
Implementation Method 3
image recording is performed by transferring the toner image formed on the photoreceptor to a recording material such as recording paper or a plastic sheet
Data Source
AI summary
The process cartridge is configured such that a toner flow path formed of an inner wall of the developing chamber and the surface of the toner supplying roller is formed upstream of the toner supplying roller in a rotation direction with respect to the position where the developing roller is in contact with the toner supplying roller, a closest distance between the inner wall of the developing chamber and the surface of the toner supplying roller in the toner flow path is 1.0 mm or greater and 5.0 mm or less, a peripheral speed ratio R between the developing roller and the toner supplying roller satisfies a range of 1.1 to 2.5, and a toner satisfying a predetermined requirement is used.