Fixing Nip Pressure Control for Belt Protection

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Solution Overview

Problem

Existing image forming devices suffer from damage to the belt during the initial stages of printing, as there is no effective technique to mitigate this issue.

Innovation Solution

The image forming device incorporates a pressure modifying mechanism that adjusts the nip pressure from a lower second nip pressure to a higher first nip pressure after the roller starts driving upon receiving a print command, ensuring the belt is protected during the initial stages of printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the nip pressure is maintained at a high level from the start of printing, then the image fixation quality is improved, but the belt damage increases

Engineering Contradiction:

Improveimage fixation qualityVSAvoidbelt damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by starting to drive the roller before modifying the nip pressure to the first (higher) pressure. This preliminary driving action allows the belt to be properly positioned and tensioned before the full fixing pressure is applied, preventing belt damage while ensuring subsequent image fixation quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the nip pressure over time, transitioning from a second (lower) nip pressure to a first (higher) nip pressure during the printing operation. This dynamic pressure modification allows the system to balance belt protection during initial operation with effective image fixation during normal operation

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If the nip pressure is reduced to protect the belt, then the belt damage is reduced, but the image fixation efficiency decreases

Engineering Contradiction:

Improvebelt damageVSAvoidimage fixation efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system implements periodic action by alternating between different nip pressure levels based on the printing state. During initial operation or idle periods, a lower nip pressure is applied to protect the belt. During active printing, the nip pressure is increased to ensure efficient image fixation. This periodic pressure adjustment maintains both belt longevity and printing efficiency

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system changes the nip pressure parameter from a second (lower) value to a first (higher) value based on operational requirements. This parameter modification allows the system to optimize the balance between belt protection and image fixation efficiency by selecting appropriate pressure levels for different operational phases

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11507002B2Image forming device including pressure modifying mechanism modifying nip pressure of nip formed between first fixing member and second fixing member

Publication Date: 2022.11.22 BROTHER KOGYO KK

AI summary

In an image forming device, a first fixing member has a roller. A second fixing member has a belt to form a nip together with the first fixing member. A first motor drives the roller. A pressure modifying mechanism modifies a nip pressure at the nip to selected one of a first nip pressure and a second nip pressure smaller than the first nip pressure. A controller starts driving the first motor to drive the roller in a case where a print command is received in a state that the nip pressure is the second nip pressure. The controller modifies the nip pressure from the second nip pressure to the first nip pressure after the driving is performed and fixes the developer image on the sheet in a state that the nip pressure is the first nip pressure.