Developing Roller Nip Disengagement Error Detection

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Solution Overview

Problem

Image forming apparatuses face challenges in detecting development nip disengaging errors, which can lead to deformation of the developing roller and damage to the photoconductor due to prolonged contact, and inefficient toner usage during non-image forming intervals.

Innovation Solution

An image forming apparatus and method that utilize a control unit to form a test pattern on the photoconductor, detect its transfer to an intermediate transfer belt using a sensor, and determine if a development nip disengaging error occurred by analyzing the detection time and length of the test pattern, allowing for accurate identification of nip formation and disengagement states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the developing roller and photoconductor remain in contact for a long time, then the development nip is maintained for continuous image forming, but the developing roller deforms and the photoconductor is damaged

Engineering Contradiction:
Improvecontinuous image forming capabilityVSAvoidcomponent durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The developing roller periodically contacts and separates from the photoconductor. During image forming, they contact to form development nip; during non-image forming intervals, they separate to prevent damage. This periodic engagement/disengagement resolves the contradiction by allowing continuous operational capability while preventing component degradation through regular separation.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the developing roller and photoconductor are separated during non-image forming intervals, then component damage is prevented, but toner may be wasted due to improper disengagement

Engineering Contradiction:
Improvecomponent protectionVSAvoidtoner waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

A sensor detects whether the developing roller has properly disengaged from the photoconductor during non-image forming intervals. The control unit receives this feedback and determines if disengagement is complete. Based on this feedback, the system can identify improper disengagement that would cause toner waste while still protecting components through timely separation detection.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If a sensor is added to detect the test pattern, then development nip disengaging errors can be detected, but device complexity increases

Engineering Contradiction:
Improveerror detection accuracyVSAvoidsensor and control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A test pattern serves as an intermediary element to enable error detection. The test pattern is formed on the photoconductor and its transfer to the intermediate transfer belt is detected by the sensor. This intermediary test pattern allows the system to indirectly monitor developing roller disengagement status without requiring complex direct measurement mechanisms, thus reducing overall system complexity while maintaining detection accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables precise detection of development nip disengaging errors, preventing damage and optimizing toner usage by ensuring accurate nip formation and disengagement, thereby extending the life span of components and improving operational efficiency.

Implementation Method 1

a charging device to apply a charging voltage to charge the photoconductor

Methodology Applied
Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 2

an exposing device to expose the photoconductor to light to form an electrostatic latent image thereon

Methodology Applied
Scientific EffectPhotoconductive effect: Photoconductivity

Implementation Method 3

a sensor to detect the test pattern transferred to the intermediate transfer belt

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentEP3475761B1Image forming apparatus capable of detecting development nip disengaging error and method of detecting development nip disengaging error
Publication Date: 2022.05.11 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3475761B1 patent drawingFigure 1
  • EP3475761B1 patent drawingFigure 2
  • EP3475761B1 patent drawingFigure 3A

AI summary

An image forming apparatus capable of detecting a development nip disengaging error and a method of detecting a development nip disengaging error are provided. According to an example method, a test pattern is formed on a photoconductor of an image forming apparatus, the test pattern transferred to an intermediate transfer belt is detected through a sensor from a time when an operation of an adjusting member moving a developing roller is controlled such that the developing roller moves from a disengaging position where the developing roller is spaced from the photoconductor to disengage a development nip from the photoconductor to a developing position where the developing roller is in contact with the photoconductor to form the development nip, and whether the development nip disengaging error occurred is determined based on the detected test pattern.