Conductive Member Gap Retention for Charging Roller
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining a consistent gap between the charging roller and the image bearing member, leading to fluctuations in charge potential and image quality due to dimensional changes caused by ambient conditions and wear over time.
Innovation Solution
A conductive member with a conductive supporting member, an electrical resistance adjusting layer, and cap-like gap retainers is used, featuring a continuous or discontinuous fixing groove and step portions to maintain a precise gap, reducing fluctuations and ensuring consistent charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact-type charging method using a charging roller is used, then the image bearing member can be charged uniformly, but the charging roller may vibrate and generate noise, and toner may adhere to the charging roller
Solution Approach 1:
The patent introduces a charging belt as an intermediary between the charging roller and the image bearing member. The charging belt contacts the image bearing member to transfer charge, while the charging roller charges the charging belt from behind. This mediator structure allows the charging roller to remain non-contacting with the image bearing member, eliminating vibration and noise issues while maintaining uniform charging through the belt's flexible contact.
2Measurement precision
If the gap between the charging roller and image bearing member is reduced to improve charging precision, then charging consistency improves, but the gap becomes sensitive to dimensional changes from ambient conditions and wear
Solution Approach 1:
The charging belt serves as a flexible intermediary that can accommodate gap variations. Even if the gap between the charging roller and image bearing member fluctuates due to thermal expansion or wear, the belt maintains consistent contact with the image bearing member surface, ensuring stable charging performance without requiring extremely precise gap control.
Solution Approach 2:
The patent changes the charging mechanism from direct roller-to-drum contact to roller-to-belt contact with indirect belt-to-drum charging. This parameter change allows the system to tolerate larger gap variations while maintaining charging precision, as the flexible belt can conform to the image bearing member surface regardless of minor positional deviations.
3Object-generated harmful factors
If a non-contact type charger with a large gap is used, then vibration and noise are reduced, but charging precision and consistency deteriorate
Solution Approach 1:
The charging belt acts as a flexible mediator that bridges the gap between the non-contact charging roller and the image bearing member. The belt maintains close contact with the image bearing member surface while being charged from behind by the roller, achieving both vibration reduction (through non-contact roller operation) and charging precision (through flexible belt contact).
Solution Approach 2:
The patent employs a flexible charging belt instead of a rigid charging roller structure. This thin film structure can conform to the image bearing member surface, maintaining consistent charging contact even with larger gaps, while the rigid charging roller behind it operates without contact to avoid vibration and noise.
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 maintains a stable gap between the charging roller and image bearing member, enhancing charging consistency and image quality over extended periods, even under varying ambient conditions.
Implementation Method 1
a continuous or discontinuous fixing groove which is provided in the vicinity of each of both ends of the conductive supporting member in a peripheral direction; step portions which are disposed in the vicinity of each of the both ends of the electrical resistance adjusting layer; and cap-like gap retainers which are provided to the step portions
Implementation Method 2
an electrical resistance adjusting layer which is formed on the conductive supporting member
Implementation Method 3
the charging roller 212 charges an image bearing member 211 while abutting the photoreceptor 211. When a direct current (DC) voltage is applied to the charging roller 212 in contact with the image bearing member 211 from a power source, not shown, the surface of the image bearing member 211 is uniformly charged.
Implementation Method 4
when the surface of the image bearing member 211 is irradiated with the laser beam 213 in accordance with image data, an electrical potential (hereinafter 'potential') of the irradiated portion of the image bearing member 211 is reduced.
Data Source
AI summary
A conductive member includes a conductive supporting member provided facing an image bearing member and including a continuous or discontinuous fixing groove provided in the vicinity of each of both ends of the conductive supporting member in a peripheral direction thereof, an electrical resistance adjusting layer formed on the conductive supporting member and including a step portion which includes at least one step disposed in the vicinity of each of the both ends of the electrical resistance adjusting member, and gap retainers each provided to the step portion and including a cylinder portion which contacts at least one surface of the step portion, and an end plate so that a predetermined gap is formed between the image bearing member and the electrical resistance adjusting layer. The end plate contacts at least one surface of the step portion and fits into the fixing groove.