Single PCB Integration for Image Forming Apparatus EMI Reduction

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Solution Overview

Problem

Conventional image forming apparatuses require separate Printed Circuit Boards (PCBs) for power, high-voltage, and control circuits, increasing volume, manufacturing cost, and electromagnetic interference (EMI) due to the need for multiple PCBs and wire harnesses to connect them.

Innovation Solution

Integration of power, high-voltage, and control circuits onto a single circuit board, with a Switching Mode Power Supply (SMPS) and High Voltage Power Supply (HVPS) circuits and a System on Chip (SoC) controller, eliminating the need for wire harnesses and reducing EMI, while using a shield plate to minimize noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If separate PCBs are used for power circuit, high-voltage power circuit, and control circuit, then each circuit can be independently designed and manufactured, but the volume and manufacturing cost increase due to multiple PCBs and wire harnesses

Engineering Contradiction:

ImproveIndependent circuit design and manufacturingVSAvoidVolume of image forming apparatus

Core Design Contradiction:

Ease of manufactureVSVolume of stationary object

Solution Approach 1:

The patent merges the power circuit, high-voltage power circuit, and control circuit onto a single PCB, eliminating the need for multiple separate PCBs and wire harnesses. This integration reduces the overall volume of the image forming apparatus while maintaining the functional independence of each circuit through proper circuit layout and grounding techniques.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If separate PCBs are used for power circuit, high-voltage power circuit, and control circuit, then each circuit can be independently designed and manufactured, but the manufacturing cost increases due to multiple PCBs and wire harnesses

Engineering Contradiction:

ImproveIndependent circuit design and manufacturingVSAvoidManufacturing cost

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple circuits onto a single PCB, eliminating the need for multiple separate PCBs and wire harnesses. This reduces the total component count and assembly steps, thereby lowering manufacturing cost while maintaining circuit functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the EMI shielding function from separate components and integrates it directly into the PCB structure through ground planes and shielding layers, eliminating the need for separate EMI shielding components and reducing overall manufacturing complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If wire harnesses are used to connect separate PCBs, then circuits can be connected, but EMI measures should be prepared to remove EMI element emitted from the harness

Engineering Contradiction:

ImproveCircuit connectionVSAvoidEMI emitted from harness

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates wire harnesses by integrating all circuits onto a single PCB, thereby removing the source of EMI emissions from the harness. The PCB itself provides a controlled impedance path and shielding through its ground planes and protective layers, preventing EMI generation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #2Taking out (Extraction)

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 integration reduces manufacturing costs, minimizes EMI, and decreases the volume of the image forming apparatus by eliminating the need for multiple PCBs and wire harnesses, while maintaining signal integrity through optimized trace design and component placement.

Implementation Method 1

a power supply unit to convert alternating current (AC) power input to the image forming apparatus into direct current (DC) power

Methodology Applied

Scientific EffectElectromagnetic transformation: Electromagnetic Induction

Implementation Method 2

a high-voltage power unit to convert the converted DC power to a predetermined voltage

Methodology Applied

Scientific EffectElectromagnetic transformation: Electromagnetic Induction

Implementation Method 3

using a shield plate to minimize noise

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentUS8717605B2Image forming apparatus and circuit board of image forming apparatus

Publication Date: 2014.05.06 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

An image forming apparatus that includes a power supply unit to convert AC power input to the image forming apparatus into DC power, a high-voltage power unit to convert the converted DC power to high voltage, an image forming unit to form an image using the converted high voltage, and a controller to control operation of the image forming unit, where the power supply unit, the high-voltage power unit, and the controller are disposed on a single circuit board.