Charging Brush Contact Force for Toner Collection
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Solution Overview
Problem
Conventional cleaning members, such as rubber blades, are ineffective in removing smaller spherical toner particles from electrophotographic image forming apparatuses, and rotatable cleaning brushes face issues with incomplete collection due to inadequate contact with toner particles.
Innovation Solution
A cleaning device with a charging brush and a cleaning brush roller, where the charging brush applies a controlled contact force to ensure reliable charging of toner particles, followed by the cleaning brush collecting these particles from the image bearing surface, with the contact force of the charging brush set between 0 N/m and 1.5 N/m to ensure complete collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rubber blade is used as the cleaning member, then the structure is simple, but the cleaning ability for spherical toner particles of smaller diameters is insufficient
Solution Approach 1:
The invention changes the physical parameters of the cleaning member by replacing the rubber blade with a rotatable cleaning brush having bristles of specific length (0.5-2.0 mm) and density (1000-5000 bristles/cm²). This parameter change enables effective contact with and removal of spherical toner particles of smaller diameters while maintaining structural feasibility
Solution Approach 2:
The invention applies curvature by using a rotatable cleaning brush with cylindrical geometry instead of a flat rubber blade. The rotational motion and three-dimensional bristle structure enable better adaptation to the curved surface of the photosensitive member and intermediate transfer belt, improving toner particle contact and removal efficiency
2Reliability
If the charging brush is forced against the belt to ensure contact, then charging reliability improves, but toner particles may be transported through without contact when large amounts are present
Solution Approach 1:
The invention makes the charging brush dynamic by allowing it to rotate along with the intermediate transfer belt rather than being forced stationary against the belt. This rotational dynamics enables the brush bristles to continuously engage with toner particles passing through the contact region, ensuring reliable charging even when large amounts of toner are present
Solution Approach 2:
The charging brush performs preliminary charging action on toner particles before they reach the cleaning brush. By positioning the charging brush upstream in the rotational direction, toner particles are charged with normal polarity first, enabling subsequent effective collection by the cleaning brush
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 that all or substantially all toner particles are collected from the image bearing surface, improving the cleaning efficiency and reducing deficiencies in toner removal.
Implementation Method 1
In the contact region the toner particles 100 are brought into contact with the bristles 176 of the brush 174 to have electric charge of normal polarity, for example, negative polarity
Data Source
AI summary
A cleaning device for use with an electrophotographic image forming apparatus has a charging brush positioned in contact with an endless image bearing surface of a rotatable image bearing member to form a contact region in which the brush provides an electric charge with a certain polarity to toner particles passing through the contact region according to a rotation of the image bearing member, and a cleaning member positioned on a downstream side with respect to a rotational direction of the image bearing member and in contact with the image bearing surface of the image bearing member to collect the toner particles from the image bearing surface. The charging brush has a base and a number of bristles planted in the base. A contact force of the charging brush against the image bearing surface is set to be more than 0 N/m and equal to or less than 1.5 N/m.