Holding Roller Speed and Bias Control for Toner Scattering
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Solution Overview
Problem
In image forming apparatuses, the scattering of attached matter around the cleaning roller occurs when changing the bias from collection to reattachment, leading to reduced image quality and apparatus pollution.
Innovation Solution
An image forming apparatus with a holding roller and control units for bias and speed control, applying a first bias during image forming and a second bias during collecting, while reducing the holding roller's speed to minimize centrifugal force and scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bias is changed from collection to reattachment, then the attached matter is transferred from the holding roller to the image carrier, but the attached matter scatters around the holding roller
Solution Approach 1:
The holding roller rotates at a reduced speed before the bias is changed from collection to reattachment mode. This preliminary speed reduction prevents the attached matter from scattering when the bias changes, while still allowing the transfer of attached matter from the holding roller to the image carrier to occur effectively
Solution Approach 2:
The holding roller's rotating speed is dynamically adjusted based on the operational phase: it rotates at a first speed during image forming, reduces to a second (lower) speed during the collecting operation before bias change, and then returns to the first speed after the bias is changed. This dynamic speed adjustment resolves the contradiction between maintaining collecting efficiency and preventing scattering
2Productivity
If the holding roller rotates at high speed, then the collecting operation is efficient, but centrifugal force causes attached matter to scatter
Solution Approach 1:
The holding roller operates in periodic cycles: rotating at high speed for image forming, then reducing to low speed for the collecting operation where bias is changed, and subsequently returning to high speed. This periodic alternation between high and low speeds allows efficient collecting while minimizing centrifugal force-induced scattering during the critical bias transition phase
Solution Approach 2:
The rotating speed parameter of the holding roller is changed from a first speed to a second (lower) speed during the collecting operation. This parameter change reduces centrifugal force and prevents scattering of attached matter when the bias is changed, while still maintaining adequate collecting efficiency
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 suppresses the scattering of attached matter, maintaining image quality and reducing internal pollution by gradually reducing the holding roller's power and speed during the collecting process.
Implementation Method 1
a bias control unit configured to control a bias to be applied to the holding roller... applying a first bias for moving the matter attached on the surface of the image carrier onto the holding roller; and during the collecting operation, applying a second bias for moving the attached matter held on the holding roller onto the image carrier
Implementation Method 2
controlling the holding roller to rotate at a second rotating speed, which is slower than the first rotating speed, at least for a first period after the bias control unit applies the second bias to the holding roller... effectively suppresses the scattering of attached matter
Data Source
AI summary
An image forming apparatus is configured to perform a collecting operation for moving the attached matter held on a holding roller onto the photosensitive drum and collecting the attached matter by a collecting unit. A bias control unit for controlling a bias applied to the holding roller is configured to: during an image forming operation, apply a first bias for moving the matter onto the holding roller; and during the collecting operation, apply a second bias for moving the attached matter onto the photosensitive drum. A speed control unit is configured to: control the holding roller to rotate at a first rotating speed during the image forming operation; and in a progress of the collecting operation, control the holding roller to rotate at a second rotating speed for a first period after the bias control unit applies the second bias to the holding roller.