Capacitive Paper Tray Sensing with Segmented Ground Planes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing printing systems struggle to accurately determine paper size, stack height, and dielectric properties within a paper tray using conventional sensing mechanisms, which can lead to inefficiencies in paper feeding and processing.
Innovation Solution
A capacitive sensing system utilizing at least two capacitive sensors with respective electrodes, CIN1 and CIN2, positioned relative to the paper width and length, measures capacitance changes to determine paper size, stack height, and dielectric properties, allowing for precise paper tray status monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensing mechanisms are used to determine paper size, stack height, and dielectric properties, then the system can detect paper tray status, but the measurement precision is insufficient leading to feeding errors
Solution Approach 1:
The paper tray bottom is divided into multiple ground plane segments (first ground plane segment, second ground plane segment, third ground plane segment) that are electrically isolated from each other. Each capacitive sensor (first capacitive sensor, second capacitive sensor, third capacitive sensor) is positioned above a specific ground plane segment, allowing independent measurement of capacitance values (CA1, CA2, CA3) for different paper regions. This segmentation enables precise determination of paper width, length, and dielectric properties by comparing capacitance differences between segments.
Solution Approach 2:
The patent replaces conventional mechanical sensing mechanisms (such as mechanical switches, optical sensors, or physical contact-based detectors) with a capacitive sensing system. The capacitive sensors measure changes in capacitance values based on the proximity and dielectric properties of paper, eliminating the need for mechanical contact or complex optical alignment. This substitution provides non-contact, high-precision measurement of paper dimensions and properties.
2Measurement precision
If multiple capacitive sensors with segmented ground planes are implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The capacitive sensing system with segmented ground planes serves multiple functions simultaneously: it measures paper width, paper length, paper dielectric properties, and paper tray status. The same set of capacitive sensors (first, second, and third capacitive sensors) and ground plane segments used for width measurement also enable length and dielectric measurement through different capacitance comparison methods. This multi-functionality reduces the need for separate sensing systems for each measurement type.
Solution Approach 2:
The patent combines the measurement functions for paper width, length, and dielectric properties into a single integrated capacitive sensing system. The segmented ground planes (first, second, and third ground plane segments) are electrically isolated but spatially arranged to enable multiple measurements. The control system processes capacitance values from all sensors simultaneously to determine multiple paper characteristics in one measurement cycle, reducing overall system 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
The capacitive sensing system provides accurate measurements of paper size, stack height, and dielectric properties, enabling efficient paper feeding and processing by reducing errors and improving system performance.
Implementation Method 1
measuring a capacitance CA1=CIN1 to ground; measuring a capacitance CA2=CIN2 to ground
Data Source
AI summary
A capacitive sensing system based on projected self-capacitance is suitable for use in printing systems/products to sense paper tray status. In example embodiments, a capacitive sensing system is adapted for sensing the condition/characteristics of paper in the paper tray, such as paper size, stack height and page count and paper dielectric. The capacitive sensing system can be configured with one or more shielded capacitive sensors incorporated into the paper tray, and oriented relative to the paper according to the paper condition/characteristic sensed.