Fixing Belt Separator Structure for Stable Sheet Release Gap

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Solution Overview

Problem

Existing image forming apparatuses face challenges in optimizing the gap between the fixing belt and the sheet separation plate without increasing complexity or cost, leading to potential damage or jamming issues.

Innovation Solution

A nip forming device with a sheet separation assembly that includes a separation plate with pivot-restricted tabs and flanges to stabilize the fixing belt, ensuring a stable gap without the need for complex drivers or sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the gap between the fixing belt and the sheet separation plate is made small to improve separation efficiency, then the sheet separation plate contacts the fixing belt easily causing damage to the belt and faulty images, but if the gap is made large then the sheet passes through easily and gets jammed

Engineering Contradiction:
Improveseparation efficiencyVSAvoidbelt damage and jamming risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The sheet separation plate is designed to be movable rather than fixed, allowing it to dynamically adjust its position. The plate can move closer to the fixing belt when not in use to maintain a small gap for efficient separation, and move away when a sheet is present to prevent contact and jamming, thus resolving the contradiction between separation efficiency and reliability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The movable sheet separation plate automatically adjusts its position based on the presence or absence of a sheet, eliminating the need for complex sensor-driven adjustment mechanisms. The plate self-regulates the gap size to optimize both separation efficiency and prevent belt damage or jamming

Inventive Principle:
Principle #25Self-service

2Productivity

If a sheet separation plate mover with driver and sensors is used to adjust the gap, then the gap can be optimized for separation, but the construction becomes complex and costs increase

Engineering Contradiction:
Improveseparation optimizationVSAvoidconstruction complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the complex driver and sensor components from the sheet separation plate mover, retaining only the essential movable plate structure. This simplification achieves the same separation optimization function through a much simpler mechanical design, directly addressing the contradiction between productivity and device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The movable sheet separation plate automatically adjusts its position based on the presence or absence of a sheet, eliminating the need for complex sensor-driven adjustment mechanisms. The plate self-regulates the gap size to optimize both separation efficiency and prevent belt damage or jamming

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4194955B1Nip forming device and image forming apparatus
Publication Date: 2026.05.13 RICOH CO LTD
  • EP4194955B1 patent drawingFigure 1
  • EP4194955B1 patent drawingFigure 2~3
  • EP4194955B1 patent drawingFigure 4~5

AI summary

A nip forming device (9) includes an endless belt (20) and a pressure rotator (21) that presses against a nip former (22) via the endless belt (20) to form a nip (N) between the endless belt (20) and the pressure rotator (21), through which a conveyed object (P) is conveyed. A separator (310) is disposed downstream from the nip (N) in a conveyance direction of the conveyed object (P). The separator (310) separates the conveyed object (P) from the endless belt (20). The separator (310) includes a non-contact portion (311) that is separated from the endless belt (20) and a contact portion (313) that contacts the endless belt (20) and retains a gap (G2) having a predetermined size between the non-contact portion (311) and the endless belt (20).