Process Cartridge Roller Speed Ratio for Ghost-Free Printing
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Solution Overview
Problem
Existing image forming apparatuses face issues with toner deterioration and image defects such as ghosts and development stripes due to improper peripheral speed ratios and toner characteristics in high-speed printing configurations.
Innovation Solution
A process cartridge design with a developing roller and toner supplying roller having opposite surface movement directions and specific peripheral speed ratios (1.1≤R≤2.5), using toner with controlled circularity and external additives to suppress toner deterioration and image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the movement direction of the developing roller surface is the same as the toner supplying roller surface, then high-speed printing is enabled, but undeveloped toner accumulates causing ghost image defects
Solution Approach 1:
The patent inverts the conventional configuration by making the developing roller and toner supplying roller rotate in opposite directions at their contact point. This reversal prevents undeveloped toner from accumulating on the developing roller surface, eliminating ghost image defects while maintaining high-speed printing capability.
2Reliability
If the movement direction of the developing roller surface is opposite to the toner supplying roller surface, then ghost image defects are prevented, but toner deterioration occurs due to large stress
Solution Approach 1:
The patent optimizes the peripheral speed ratio between the developing roller and toner supplying roller to a specific range (0.5 ≤ VRS/VD ≤ 2.0). This parameter control reduces the stress applied to toner particles during the opposite-direction rotation, preventing toner deterioration such as additive embedding and migration while maintaining the benefits of ghost prevention.
3Reliability
If toner is supplied with high stress to prevent ghost images, then image defects are reduced, but toner additives embed and migrate causing development stripes
Solution Approach 1:
By controlling the peripheral speed ratio within the optimized range and selecting appropriate toner material properties (circularity 0.930-0.970), the patent reduces mechanical stress on toner particles. This prevents the embedding and migration of external additives that cause development stripes, while still preventing ghost image defects through the opposite rotation configuration.
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 design effectively prevents ghosts and development stripes, ensuring high-quality images even in long-term use, while maintaining toner stability and extending cartridge life.
Implementation Method 1
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 2
a toner supplying roller that is disposed in contact with the developing roller and supplies the toner to the developing roller
Data Source
AI summary
A process cartridge is configured such that a movement direction of a surface of a developing roller is opposite to a movement direction of a surface of a toner supplying roller in a position where the developing roller is in contact with the toner supplying roller, the developing roller and the toner supplying roller rotate to satisfy a peripheral speed ratio R of 1.1 to 2.5, and a toner satisfying predetermined requirements is used.