Printing Apparatus Substrate Shielding Against Motor Noise
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Solution Overview
Problem
Printing apparatuses face noise interference from electromagnetic waves generated by components like motors, which can affect the operation of the device through connectors.
Innovation Solution
A configuration that includes a substrate covered by multiple metal plates surrounding the main circuit substrate, with a communication cable coupled via a through-hole covered by a metal cover, effectively shields the substrate from external electromagnetic waves, reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If connectors are used for communication with external apparatus, then communication functionality is improved, but electromagnetic waves from motors can enter through connectors and cause noise interference
Solution Approach 1:
A filter circuit is introduced as an intermediary component between the connector and the main circuit substrate. The filter circuit includes a capacitor connected between the signal line and ground, and a resistor connected in series with the signal line. This intermediary structure allows communication signals to pass through while blocking high-frequency electromagnetic waves from the motor, thus resolving the contradiction between maintaining communication functionality and preventing electromagnetic interference.
2Object-affected harmful factors
If metal plates are added to shield the substrate, then electromagnetic wave shielding is improved, but device complexity increases
Solution Approach 1:
Instead of implementing a complete enclosure around the main circuit substrate, metal plates are strategically positioned only at critical locations where electromagnetic waves can most easily couple into the circuit. Specifically, metal plates are placed near the connector and along the signal path between the motor and the substrate. This localized shielding approach provides effective electromagnetic protection while minimizing the addition of structural complexity.
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 configuration effectively suppresses the entry of electromagnetic waves into the main circuit substrate, reducing noise and ensuring stable operation of the printing apparatus.
Implementation Method 1
a first metal plate that separates the substrate from the motor; a second metal plate disposed above the substrate, the second metal plate having a through-hole; a third metal plate; a fourth metal plate; a fifth metal plate; and a sixth metal plate. The first metal plate to the sixth metal plate surround the substrate. The cable is coupled to the connector via the through-hole. The through-hole is covered with a metal cover
Data Source
AI summary
A printing apparatus includes: a motor; a printing mechanism; a print processor; a connector; a substrate that transmits a signal received via the connector to the print processor, the print processor and the connector being mounted on the substrate; a plurality of metal plates that separate the substrate from the motor. The metal plates surround the substrate. The cable is coupled to the connector via a through-hole. The through-hole is covered with a metal cover.