Retainer Assembly Positioning Features for Toner Cartridge Circuit Alignment

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Solution Overview

Problem

The challenge in electrophotographic image forming devices is achieving precise alignment and reliable electrical connection between processing circuitry on supply items and the image forming device, while minimizing external forces and removing contaminants that can cause malfunctions.

Innovation Solution

A retainer with positional control features, such as alignment devices and deformable features, is used to accurately position the circuit board and ensure proper contact between the connector pins and terminals, preventing contaminants from interfering with the connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the circuit board is mounted on the supply item to enable electrical connection with the image forming device, then communication and data storage functions are achieved, but dimensional variations in the circuit board and tolerances in the image forming device frame lead to misalignment between connector contacts and circuit board contacts

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A retainer component acts as an intermediary between the circuit board and the image forming device frame. The retainer includes alignment features such as alignment pins that fit into corresponding alignment holes, serving as a mediator to transfer and establish precise positional relationships between the circuit board and the frame, thereby compensating for dimensional variations and tolerances

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The retainer is pre-assembled with the circuit board before installation into the image forming device. During this preliminary assembly, the circuit board is positioned and secured on the retainer with precise alignment features already in place. This preliminary positioning ensures that when the entire assembly is installed into the device, the connector contacts and circuit board contacts are properly aligned without requiring high-precision assembly at the final installation stage

Inventive Principle:
Principle #10Preliminary action

2Reliability

If connector contacts exert force on the circuit board to establish reliable electrical connection, then electrical connection stability is improved, but force imbalance between the toner cartridge and imaging unit causes print defects

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidprint defects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The force application mechanism is segmented into multiple independent contact points distributed across the connector assembly. Instead of concentrating force at a single location, multiple connector contacts apply force at different positions on the circuit board, distributing the mechanical load and preventing excessive force at any single point that could cause print defects

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connector contacts are designed with varying contact forces and characteristics at different locations. Some contacts may have higher spring pressure or different contact areas to compensate for local variations in the circuit board or frame, ensuring each contact point achieves reliable electrical connection without creating overall force imbalance that would affect printing quality

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the supply item undergoes multiple installations into the printer, then usage flexibility is improved, but contaminants such as toner and paper dust settle in the circuit board terminals, causing wear and malfunction

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidcontaminant accumulation
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The circuit board with its vulnerable terminals is extracted from direct exposure to the contaminated environment of the printer. The retainer assembly acts as a protective enclosure that houses the circuit board, allowing it to be installed and disconnected without the terminals being directly exposed to toner and paper dust during handling and installation operations

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The retainer assembly provides pre-established protection for the circuit board terminals against contaminant ingress. The structural design of the retainer with its enclosing walls and controlled access points creates a protective barrier before contaminants can reach the terminals, cushioning the vulnerable electrical contacts from the harsh printing environment during repeated installation cycles

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3168936B1Retainer assembly having positioning features for processing circuitry used with an image forming device supply item
Publication Date: 2024.03.13 LEXMARK INTERNATIONAL INC
  • EP3168936B1 patent drawingFigure 1
  • EP3168936B1 patent drawingFigure 2
  • EP3168936B1 patent drawingFigure 3

AI summary

A replaceable unit for an electrophotographic image forming device with a housing having a top, a bottom, a front, and a rear positioned between a first side and a second side of the housing as well as a a reservoir for holding toner and a side-to-side dimension that runs from the first side to the second side. An electrical contact is positioned within a pocket on the first side of the housing, with the pocket permitting an electrical connector of the image forming device to enter the pocket and mate with the electrical contact when the replaceable unit is installed in the image forming device. A first guide wall and a second guide wall are each positioned outside the pocket with each including an inclined surface to move the electrical connector of the image forming device along the side-to-side dimension toward the electrical contact during insertion of the replaceable unit into the image forming device.