Cleaning Brush Current Control for Dot Pitch Uniformity
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Solution Overview
Problem
Conventional image forming apparatuses require a lengthy preliminary rotation of the cleaning brush to restore its shape after a long period of inactivity, leading to user-unfriendliness and increased waiting time before image formation can commence, as the brush's bent state causes uneven dot pitch due to irregular rotation speed of the transfer belt.
Innovation Solution
The apparatus adjusts the cleaning current supplied to the cleaning member based on its rotation time, using a higher current for shorter periods and a lower current for longer periods to prevent irregular rotation speed and restore the brush's shape during image formation, allowing instant image formation while maintaining dot pitch uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cleaning brush is preliminarily rotated for a long period to restore its shape after lengthy cessation, then dot pitch uniformity is improved, but user wait time increases and ease of operation deteriorates
Solution Approach 1:
The patent changes the electrical parameter (cleaning current value) based on the operational state of the cleaning brush. When the brush has been stationary for a long period, a first cleaning current value is applied; when it has been rotating recently, a second cleaning current value is applied. This parameter adaptation allows the system to achieve proper cleaning效果 without requiring lengthy preliminary rotation, thus maintaining dot pitch uniformity while reducing user wait time.
Solution Approach 2:
The patent applies preliminary electrical cleaning action to the cleaning brush before image formation begins. By supplying appropriate cleaning current when the brush is in a stationary state, the toner particles are removed in advance, preventing the brush from picking up excessive toner that would cause dot pitch unevenness during subsequent operation, thereby eliminating the need for long preliminary mechanical rotation.
2Device complexity
If the cleaning brush remains in bent state after lengthy cessation, then device complexity is reduced, but image quality deteriorates due to uneven dot pitch
Solution Approach 1:
The patent replaces the mechanical solution (rotating the cleaning brush to restore its shape) with an electrical solution (applying cleaning current to remove toner particles). Instead of mechanically restoring the brush through rotation, the system uses electrostatic cleaning current to achieve the same image quality goal, thereby maintaining simplicity in the mechanical structure while ensuring image quality.
3Productivity
If the cleaning current is increased to restore the cleaning brush faster, then productivity is improved, but energy consumption increases
Solution Approach 1:
The patent applies partial cleaning action by using different cleaning current values based on the operational state. Instead of always applying maximum cleaning current, the system applies a first cleaning current value when the brush is stationary and a second (different) value when it is rotating. This partial application of cleaning current achieves sufficient cleaning效果 without excessive energy consumption, balancing productivity and energy 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
This approach enables immediate image formation without preliminary rotation, reducing user wait time and ensuring consistent dot pitch quality by minimizing the impact of the cleaning brush's bent state on the transfer belt's rotation speed.
Implementation Method 1
electrostatically remove these remaining toner particles by rotating the cleaning brush while receiving a cleaning current (electric current for cleaning) at a predetermined current value
Data Source
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AI summary
An image forming apparatus (1) includes: an intermediate transfer belt (11) for, by rotation thereof, transferring a toner image on a surface thereof; a cleaner (82) for removing toner particles after the transfer by rotation of a cleaning brush (82) which touches the surface of the intermediate transfer belt (11) and rotated during the transfer; a current supplier (91) for supplying a cleaning current having a predetermined value (I2) to the cleaning brush (82) in accord with the transfer; and a controller (6) for controlling the intermediate transfer belt (11), cleaner (82) and current supplier (91). The controller (6) obtains a current time T1 and a previous rotation end time T2 of the cleaning brush (82), and when a time period during which the cleaning brush (82) has not rotated, which is calculated from the current time T1 and the rotation end time T2, is equal to a predetermined time period or longer, sets the cleaning current to "I1".