Lubricated Developer Carrying Member Torque Control
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Solution Overview
Problem
The existing developing devices face issues with high torque generation during initial use due to lubricant depletion and image defects caused by residual lubricant mixing with toner, leading to increased load on the driving system and defective images with uneven density or white dots.
Innovation Solution
An image forming apparatus is configured to retain lubricant on the developer carrying member by applying a potential difference between the developer supplying member and carrying member, ensuring the lubricant is charged to the same polarity as the developer, with a higher charge density, and executing sequences for lubricant retention and removal to prevent image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the developing roller is coated with lubricant before use, then the frictional force between the developing roller and abutment members is reduced, but the lubricant is depleted during initial operation causing increased torque and load on the driving system
Solution Approach 1:
The developing roller is coated with lubricant before use to reduce friction during initial operation. The lubricant is applied in advance to ensure the surface is adequately lubricated when the developing roller first contacts the abutment members, preventing excessive friction and torque during the critical initial phase of operation.
Solution Approach 2:
The patent controls the charge amount of the lubricant to be smaller than that of the developer. This parameter change ensures that the lubricant remains on the developing roller surface long enough to provide friction reduction, while preventing excessive charge accumulation that would cause image defects. The charge amount is specifically controlled to balance lubricant retention with image quality.
2Force
If the coating agent is applied on the developer carrying member, then the frictional force is reduced, but the coating agent mixes with the developer causing image defects such as uneven density and white dots
Solution Approach 1:
The lubricant is applied only to the surface of the developing roller where it is needed for friction reduction, while the bulk of the developer remains in the developing container. This local application ensures that the lubricant provides friction reduction without excessively mixing with the developer, thereby preventing image defects such as uneven density and white dots while maintaining the necessary lubrication.
Solution Approach 2:
The charge amount of the lubricant is controlled to be smaller than that of the developer. This parameter control ensures that the lubricant does not become excessively charged and mix harmfully with the developer during normal operation. The controlled charge amount allows the lubricant to remain relatively isolated while still providing the necessary friction reduction, preventing image quality degradation.
3Power
If the lubricant is retained on the developer carrying member, then the torque required for rotation is reduced, but the lubricant may be transferred to the image bearing member causing image defects
Solution Approach 1:
The charge amount of the lubricant is controlled to be smaller than that of the developer. This parameter change creates a charge differential that prevents the lubricant from being excessively transferred to the image bearing member during normal operation. The controlled charge amount allows the lubricant to remain on the developing roller surface, providing torque reduction, while preventing harmful transfer that would cause image defects.
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 effectively reduces the torque required for the developing device's operation by maintaining lubricant on the developer carrying member until toner coating is complete and prevents image defects by ensuring the lubricant is removed or directed away from the image formation area, resulting in improved image quality and reduced wear on the driving system.
Implementation Method 1
the lubricant is to be charged to the same polarity as the developer, with an absolute value of a charge amount per unit mass of the lubricant being larger than an absolute value of a charge amount per unit mass of the developer
Implementation Method 2
executing a first sequence of applying a potential difference between the developer supplying member and the developer carrying member before image formation to form an electric field in a direction in which the lubricant is directed from the developer supplying member toward the developer carrying member
Implementation Method 3
triboelectrification charges are applied to the developer due to the friction with the developer amount regulating blade
Data Source
AI summary
An image forming apparatus configured to form an image with developer includes an image bearing member configured to bear an image of the developer, a developer carrying member configured to carry the developer to supply the developer to the image bearing member, and a developer supplying member configured to supply the developer to the developer carrying member. At least a part of a surface of the developer carrying member is coated with lubricant charged to the same polarity as the developer, and an absolute value of a charge amount per unit mass of the lubricant is larger than that of the developer. The image forming apparatus executes a first sequence of applying a potential difference between the developer supplying member and the developer carrying member before image formation to form an electric field to suppress movement of the charged lubricant from the developer carrying member to the developer supply member.