High-Voltage Board Shielding in Image Forming Apparatus

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Solution Overview

Problem

In image forming apparatuses, the close arrangement of high-voltage and main control boards leads to electrical radiation noise interference, heat issues, and increased size, making it difficult to reduce the device's size effectively.

Innovation Solution

The high-voltage board is positioned on the outer side of the main board within a side region of the apparatus, serving as a shield to reduce external interference and eliminate the need for a separate shield plate, while maintaining efficient use of the limited space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If the high-voltage board and main board are arranged to overlap and be close to each other to reduce the size of the image forming apparatus, then the size of the apparatus is reduced, but electric radiation noise generated at each board causes abnormal operation and leaked noise influences external devices

Engineering Contradiction:

Improvesize of image forming apparatusVSAvoidelectric radiation noise interference

Core Design Contradiction:

Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The high-voltage board is integrated to serve dual functions: as a functional circuit board and as a shield plate for the main board. By merging the shielding function into the high-voltage board itself, the patent eliminates the need for a separate shield plate, thereby reducing the overall apparatus size while maintaining effective noise shielding.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent converts the potentially harmful high-voltage board (which generates electric radiation noise) into a beneficial shielding element. By positioning the high-voltage board on the outer side of the main board, it acts as a shield that protects the main board from external electromagnetic interference while its own structure helps contain its generated noise.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If a separate shield plate is added to shield electric radiation noise from the high-voltage board, then the noise shielding effect is improved, but the boards increase in size making it difficult to contribute to size-reduction

Engineering Contradiction:

Improveelectric radiation noise shieldingVSAvoidsize of boards

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The shielding function is merged with the high-voltage board structure itself. The high-voltage board is positioned and configured to serve as the shield plate for the main board, eliminating the need for a separate shielding component and thereby avoiding any increase in board size.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The high-voltage board is given multiple functions: it performs its primary high-voltage generation function while simultaneously serving as a shield plate for electromagnetic interference protection. This multi-functionality eliminates the need for dedicated shielding components, maintaining compact dimensions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Length of stationary object

If the main control board is overlapped on the high-voltage generator board to shorten the interface distance, then the interface between boards is shortened, but the main control circuit directly receives electric radiation noises from the transistor or transformer and malfunctions increases

Engineering Contradiction:

Improveinterface distance between boardsVSAvoidmain control circuit stability

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

Instead of placing the main board on the outer side with the high-voltage board inside (which would expose the main board to noise), the patent inverts the arrangement by placing the high-voltage board on the outer side. This inversion makes the high-voltage board the first line of defense against external interference while it shields the main board from its own and external noise.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The high-voltage board acts as an intermediary shield between the external environment and the main board. By positioning it on the outer side, it mediates the electromagnetic environment, blocking external noise from reaching the main board while the short interface distance maintains electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8929765B2Image forming apparatus

Publication Date: 2015.01.06 BROTHER KOGYO KK

AI summary

An image forming apparatus is configured to electro-photographically form an image and includes a main body frame which includes a side wall, an outer cover which covers an outer face of the main body frame, a high-voltage board which includes a high-voltage generator circuit configured to generate a high voltage and supply an electric power to a device requiring a high-voltage power source, and a main board which includes a main control circuit configured to perform a control on an image forming process of the image forming apparatus. In a side region which is formed by the side wall of the main body frame and the outer cover, the high-voltage board and the main board are disposed along the side wall to overlap with each other at least partially, and the high-voltage board is disposed on an outer side relative to the main board.