Sheet Ejection Device with Electrostatic Alignment
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Solution Overview
Problem
Existing sheet ejection devices struggle to align thin sheets effectively on a sheet output tray due to their light weight and low rigidity, leading to sheet jams and poor orderliness, as they are inclined by the electrostatic attraction forces from conductive members.
Innovation Solution
A sheet ejection device equipped with a detector to set a constant sheet drop height, non-conductive sheet abutting members to regulate sheet movement, and conductive members positioned behind these abutting members to attract and align the sheet edges without inclination, ensuring orderly stacking and preventing jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conductive members are used to remove static electricity from ejected sheets, then sheet alignment is improved, but thin sheets are inclined and fail to align properly due to their light weight and low rigidity
Solution Approach 1:
A non-conductive sheet abutting member is introduced as an intermediary between the conductive member and the thin sheet. This abutting member has a sheet regulating surface that contacts the sheet to maintain it in a substantially perpendicular posture, preventing inclination while still allowing the conductive member to remove static electricity. The abutting member acts as a mediator that protects the thin sheet from being directly influenced by the electrostatic attraction force.
Solution Approach 2:
The sheet abutting member is designed with specific local properties: it has a non-conductive surface to prevent direct electrostatic attraction, a regulated surface geometry to control sheet contact, and is positioned at a specific height (sheet regulating surface height) to ensure proper sheet posture. These local quality variations allow different regions of the system to perform specialized functions.
2Manufacturing precision
If conductive members are positioned close to the sheet output tray to effectively remove static electricity, then sheet alignment is improved, but thin sheets lean against the end fence and side fence due to electrostatic attraction
Solution Approach 1:
The non-conductive sheet abutting member serves as a protective intermediary between the conductive member and the thin sheet. It allows the conductive member to be positioned close to the output tray for effective static removal while preventing the thin sheet from directly contacting the conductive member's electrostatic field, thus avoiding leaning and jamming issues.
Solution Approach 2:
The system converts the harmful electrostatic attraction force into a beneficial process by using the conductive member to remove static electricity from sheets, while the non-conductive abutting member ensures this happens without causing thin sheets to lean or jam. The potential harm of strong electrostatic forces is transformed into a useful static removal function.
3Manufacturing precision
If the sheet output tray is elevated to maintain constant sheet drop height for orderly stacking, then sheet alignment is improved, but the complexity of the ejection device increases due to additional detection and elevation mechanisms
Solution Approach 1:
The sheet output tray elevation mechanism operates automatically based on feedback from the sheet drop height position detector. The system self-regulates by detecting the actual sheet drop height and adjusting the tray elevation accordingly, eliminating the need for manual intervention or complex external control systems while maintaining constant stacking orderliness.
Solution Approach 2:
A sheet drop height position detector provides continuous feedback on the actual sheet drop height to the elevation mechanism. This feedback loop allows the system to automatically adjust and maintain constant sheet drop height, ensuring orderly stacking while keeping the control mechanism relatively simple and self-regulating.
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 types of sheets, including thin sheets, are stacked orderly on the output tray, reducing the likelihood of sheet jams and effectively removing static electricity, thereby maintaining the orderliness and preventing jams.
Implementation Method 1
a conductive member 16 attached at a position lower than the sheet drop height H1 and in the vicinity of the second sheet abutting member 14 in a grounded state in the sheet width direction, and attracts the rear end portion Pd of the sheet P on the uppermost layer by electrostatic induction up to the sheet drop height position H1 on the sheet regulating surface 14a of the second sheet abutting member 14
Implementation Method 2
Each of the conductive members 16 is earthed from the sheet output tray to the image forming apparatus side... electricity is removed from the ejected sheets
Data Source
AI summary
A sheet ejection device includes a plurality of second sheet abutting members and a plurality of conductive members. Each second sheet abutting member has a non-conductive sheet regulating surface that abuts on a rear end portion in an ejecting direction of each sheet on a sheet output tray to regulate movement thereof. Each conductive member is attached at a position lower than a sheet drop height position and in the vicinity of each second sheet abutting member in a grounded state in the sheet width direction. Each conductive member attracts a rear end portion in the ejecting direction of a sheet on the uppermost layer of a plurality of sheets stacked on the sheet output tray, up to the sheet drop height position on the sheet regulating surface of the second sheet abutting member.