Sheet Discharging Device Air Blower Clinging Prevention

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Solution Overview

Problem

Conventional sheet processing apparatuses face challenges in preventing sheet clinging and bending, particularly with coated paper, which affects alignment accuracy due to high surface smoothness, inter-sheet clinging force, and low Clark stiffness.

Innovation Solution

The implementation of a sheet discharging device that uses air blowers to reduce close contact between sheets by adjusting air velocity and direction based on paper type, thickness, and size, ensuring an air layer forms between sheets to prevent clinging and bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a retainer is used to hold ejected sheets at a normal position, then sheet stacking is improved, but thin sheets can be buckled by sheet clinging and conveyed in a state of clinging to a preceding sheet

Engineering Contradiction:
Improvesheet stackingVSAvoidsheet bending
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent employs air blowers to deliver air to the sheet surface, creating an air layer that prevents sheets from clinging together. This pneumatic approach resolves the contradiction by using airflow to keep sheets separated during conveyance, preventing both stacking issues and bending of thin sheets.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent adjusts air delivery parameters (airflow rate, air delivery timing, air delivery position) based on sheet properties such as paper type, thickness, and size. By dynamically changing these parameters, the system optimizes prevention of sheet clinging while avoiding excessive air delivery that could cause sheet displacement or bending.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If air blowing is applied to prevent sheet clinging, then sheet conveyance is improved, but alignment accuracy may deteriorate due to sheet displacement

Engineering Contradiction:
Improvesheet conveyanceVSAvoidalignment accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies air blowing locally to specific regions where sheet clinging is most likely to occur, rather than uniformly across the entire sheet. The air delivery position is strategically located to prevent clinging without causing sheet displacement that would affect alignment accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts air delivery parameters based on real-time sheet conditions and properties. The air blowing is applied only when and where needed, with parameters such as airflow rate and delivery timing being adjusted according to sheet type, thickness, and size, thereby preventing clinging while maintaining alignment accuracy.

Inventive Principle:
Principle #15Dynamics

3Reliability

If air delivery parameters are increased to prevent sheet clinging, then sheet separation is improved, but sheet displacement and bending may occur

Engineering Contradiction:
Improvesheet separationVSAvoidsheet bending
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent optimizes air delivery parameters (airflow rate, air delivery timing, air delivery position) based on sheet properties such as paper type, thickness, and size. By dynamically changing these parameters, the system achieves effective sheet separation while preventing excessive air delivery that would cause sheet displacement or bending.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates sheet detection to identify sheet properties and conditions, using this information to adjust air delivery parameters in real-time. This feedback mechanism ensures that air delivery is optimized for each specific sheet, preventing both clinging and excessive displacement or bending.

Inventive Principle:
Principle #23Feedback

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 effectively prevents sheet clinging and bending, thereby enhancing alignment accuracy and stability during stacking.

Implementation Method 1

blowing air to a sheet at an air velocity that is set according to information about paper type, paper thickness, and sheet size when the sheet is ejected

Methodology Applied
Scientific EffectAir layer formation: Air Lubrication

Data Source

PatentEP2599741B1Sheet discharging device, sheet processing apparatus, image forming system, and sheet discharging method
Publication Date: 2016.04.27 RICOH CO LTD
  • EP2599741B1 patent drawingFigure 1
  • EP2599741B1 patent drawingFigure 2
  • EP2599741B1 patent drawingFigure 3

AI summary

A sheet discharging device includes: sheet discharging rollers (6) that receive each of sheets (P) conveyed thereto and discharge the sheets (P) one by one; a shift tray (202) on which the sheets discharged by the sheet discharging rollers (6) are to be stacked; an air blower (400); and a CPU (101). The air blower (400) forms an air layer (AL) between the shift tray (202) and a sheet (P1) when the sheet (P1) is dischraged onto the shift tray (202) by the sheet discharging rollerls (6), or between a sheet (P2) and the sheet (P1) that is already placed on the shift tray (202) when the sheet (P2) is discharged. The CPU (101) controls an air velocity of air to be delivered by the air blower (400) based on sheet information, thereby causing the air layer (AL) to extend to the entire surface of the sheet (P1, P2).