Image Forming Apparatus Paper Dust Control
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Solution Overview
Problem
In image forming apparatuses, the contact between the paper dust collecting roller and the sheet leads to charge polarization, causing the optical sensor's detection accuracy to deteriorate due to dust adsorption on the guide member over time.
Innovation Solution
Incorporating a control unit that switches the polarity of the voltage applied to the paper dust collecting unit, ensuring the sheet is conveyed to the optical detection unit with a charge distribution that prevents dust adsorption on the guide member, thereby maintaining detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet is brought into contact with the paper dust collecting roller to collect paper dust, then paper dust collection is improved, but the sheet is charged to the same polarity as the guide member causing dust adsorption on the guide member
Solution Approach 1:
The paper dust collecting roller alternates between a dust collection state (charged to attract paper dust) and a dust discharge state (charged to release paper dust). This periodic polarity switching allows the roller to collect paper dust during printing and discharge it during idle periods, preventing dust accumulation on the guide member while maintaining effective paper dust collection during operation.
Solution Approach 2:
The polarity of the paper dust collecting roller is dynamically changed between positive and negative states. By switching the charge polarity, the roller can alternately attract and repel paper dust, enabling both effective dust collection during printing and dust discharge during idle periods, thereby preventing dust adsorption on the guide member.
2Measurement precision
If the sheet is conveyed to the optical sensor after charging, then the optical detection function is maintained, but detection accuracy deteriorates due to dust adsorption on the guide member
Solution Approach 1:
The paper dust collecting roller periodically switches between dust collection and dust discharge states. During idle periods when no sheet is conveyed, the roller discharges accumulated dust, preventing dust adsorption on the guide member and maintaining optical detection accuracy. During printing, the roller collects dust to ensure clean sheet conveyance to the optical sensor.
Solution Approach 2:
The system performs dust discharge operations during idle periods between sheet conveyances. By utilizing the time when no sheet is being processed to discharge dust from the paper dust collecting roller, the system prevents dust accumulation on the guide member without interfering with the optical detection function during active printing operations.
3Reliability
If the paper dust collecting roller is continuously charged to collect dust, then paper dust collection is improved, but dust accumulates on the guide member over time
Solution Approach 1:
The paper dust collecting roller operates in alternating cycles of dust collection and dust discharge. During printing operations, the roller collects paper dust to maintain clean sheet conveyance. During idle periods between sheets, the roller discharges accumulated dust, preventing long-term dust accumulation on the guide member while maintaining effective paper dust collection capability.
Solution Approach 2:
The charge polarity of the paper dust collecting roller is dynamically switched between positive and negative states. This parameter change enables the roller to alternately attract and repel paper dust, allowing dust collection during printing and dust discharge during idle periods, thereby preventing dust accumulation on the guide member over time.
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 solution effectively suppresses the deterioration of detection accuracy in the optical detection unit by controlling the charge on the sheet and guide member, preventing dust accumulation and ensuring consistent performance.
Implementation Method 1
a paper dust collecting unit configured to collect, by application of a voltage, paper dust attached to a sheet
Implementation Method 2
the optical detection unit being configured to irradiate the sheet with light and receive light via the sheet
Implementation Method 3
the sheet and the guide member are brought into contact with each other and rubbed together, so that the sheet is charged to the same polarity as the guide member
Data Source
AI summary
An image forming apparatus includes a paper dust collecting unit which collects, by application of a voltage, paper dust attached to a sheet, an optical detection unit provided on a downstream side of the paper dust collecting unit in a sheet conveyance direction, which irradiates the sheet with light and receives light via the sheet, a guide member which comes into contact with the sheet to be conveyed to guide the sheet, at least one of light directed toward the sheet from the optical detection unit and light directed toward the optical detection unit from the sheet passing through the guide member, and a control unit which switches a polarity of the voltage to be applied to the paper dust collecting unit and causes the sheet charged through the paper dust collecting unit to be conveyed to the guide member.