Photosensitive Drum Charge Layout to Minimize Toner Scattering
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Solution Overview
Problem
Existing image forming apparatuses face issues with toner scattering due to the design of the cleaning brush, which holds toner and deposits it within the device, leading to contamination and inefficiencies.
Innovation Solution
The image forming apparatus is designed with specific width and potential relationships between components such as the charging, eliminating charge, and collecting members, ensuring that the surface potential outside the effective charging width but within the collecting member's contact width is greater than 0V in the same polarity direction as the toner, minimizing toner scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning brush is used to remove deposited matter from the photosensitive drum, then the deposited matter is effectively removed, but the remaining toner is held and scattered within the device
Solution Approach 1:
The patent extracts the harmful function of the cleaning brush by removing it from the system and replacing it with a collecting member that performs only the beneficial function of gathering deposited matter without holding remaining toner. The cleaning brush is completely eliminated and its cleaning function is transferred to the transfer portion and eliminating charge portion.
Solution Approach 2:
The patent introduces an eliminating charge portion as an intermediary between the transfer portion and the collecting member. This intermediary applies a negative bias voltage to eliminate remaining charge on the photosensitive drum surface, preventing toner from adhering to the collecting member while allowing deposited matter to be collected.
2Productivity
If the cleaning brush contacts the photosensitive drum surface to remove toner, then the toner is removed, but the brush holds the toner for a while causing scattering
Solution Approach 1:
The patent removes the cleaning brush entirely from the system, eliminating the problematic toner holding function. Instead, the transfer portion transfers remaining toner to the collecting member, and the eliminating charge portion immediately eliminates the charge, preventing toner adhesion and reducing holding time to near zero.
Solution Approach 2:
The patent replaces the mechanical cleaning brush system with an electrostatic system consisting of the transfer portion and eliminating charge portion. The electrostatic field eliminates charge on the drum surface, preventing toner adhesion without mechanical contact, thus eliminating the toner holding problem entirely.
3Reliability
If the collecting member contacts the photosensitive drum to collect deposited matter, then deposited matter is collected, but charge on the drum surface may interfere with collection efficiency
Solution Approach 1:
The patent applies preliminary action by using the eliminating charge portion to eliminate remaining charge on the photosensitive drum surface before the collecting member contacts the drum to collect deposited matter. This preliminary charge elimination prevents toner from adhering to the collecting member during the collection process.
Solution Approach 2:
The eliminating charge portion acts as an intermediary between the transfer portion and the collecting member. It applies a negative bias voltage to eliminate remaining charge on the drum surface, creating optimal conditions for the collecting member to collect deposited matter without interference from residual charge.
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 effectively reduces toner scattering, maintaining device cleanliness and operational efficiency by ensuring toner is collected and reused, thus enhancing the apparatus's compactness and reducing printing costs.
Implementation Method 1
a charging member configured to form a charging portion between itself and the image bearing member and to charge a surface of the image bearing member
Implementation Method 2
a eliminating charge portion configured to eliminate charge on the surface of the image bearing member
Implementation Method 3
a collecting member configured to collect a deposited matter deposited on the surface of the image bearing member in contact with the surface of the image bearing member
Data Source
AI summary
An image forming apparatus includes a rotatable image bearing member about a rotational axis extending in the axial direction, a charging member, an accommodating portion accommodating toner charged to a predetermined polarity; a developing member, a transfer portion, a static eliminating portion, and a collecting member. In the axial direction, when A is a eliminating width with which the eliminating portion discharges the surface of the image bearing member, B is an effective charging width with which the charging member charges the surface, and C is a collection contacting width with which the collecting member contacts the surface, the formula A<B<C is satisfied. In the axial direction, a surface potential of the surface in an area outside the effective charging width, inside the collection contacting width and in contact with the collecting member is a first potential larger than 0V in the same polarity direction as the predetermined polarity.