Paper Position Detector Using Graphic Shape Pattern
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Solution Overview
Problem
Conventional image forming apparatuses, such as ink jet printers, face challenges in precisely detecting paper position with respect to the paper feeding direction using low-speed sensors due to the serial output configuration of image sensors, which is time-consuming and not cost-effective for high-speed paper handling.
Innovation Solution
A paper position detector is configured to detect a detection pattern with a graphic shape whose length decreases from upstream to downstream, utilizing a control unit that processes detection signals from a low-speed sensor to calculate the paper position accurately by combining data from the main scanning direction, paper feeding speed, and detection time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a serial output image sensor is used for paper position detection, then the system cost is reduced and configuration is simplified, but the detection speed becomes insufficient for high-speed paper handling
Solution Approach 1:
The patent segments the detection task by dividing the image sensor's output into multiple processing channels. Instead of processing all pixel data serially, the control unit segments the detection signals into different scanning direction data and feeding direction data, processing them in parallel to achieve both low cost and high detection speed.
Solution Approach 2:
The patent transforms the detection approach by changing from one-dimensional serial processing to two-dimensional parallel processing. The control unit separates detection signals into main scanning direction components and sub-scanning direction components, enabling simultaneous processing along both dimensions and achieving high-speed detection with a low-speed sensor.
2Productivity
If an expensive high-speed sensor with parallel output is used, then the detection speed is sufficient for high-speed paper handling, but the system cost increases significantly
Solution Approach 1:
The patent creates a virtual parallel processing system through software/control logic that replicates the functionality of expensive parallel-output sensors. The control unit processes serial sensor data through multiple computational channels simultaneously, achieving the effect of parallel processing without the hardware cost of parallel-output sensors.
Solution Approach 2:
The patent replaces the mechanical/hardware parallel output structure with a computational/software-based parallel processing system. Instead of using multiple physical sensor outputs, the system uses a single sensor with serial output and implements parallel processing through control unit algorithms, eliminating the need for expensive parallel sensor architecture.
3Area of stationary object
If all imaging elements are operated at once to cover full width, then complete paper width detection is achieved, but the processing time increases
Solution Approach 1:
The patent extracts only the essential detection information from the full image sensor output. Instead of processing all pixel data across the full paper width, the control unit extracts specific detection pattern features and relevant position information, reducing processing time while maintaining complete detection coverage through selective data 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 approach allows for precise detection of paper position even with low-speed sensors, enabling accurate alignment of images on both sides of the paper without the need for expensive high-speed sensors, thus simplifying the system and reducing costs.
Implementation Method 1
an image sensor for detecting misregistration of paper
Data Source
AI summary
Paper has a detection pattern having a length in a main scanning direction, the length becoming shorter from upstream to downstream along a paper feeding direction. An image sensor detects the detection pattern and outputs a detection signal including data in the main scanning direction (length y). A control unit calculates a position of a vertex of the detection pattern, by using the detection signal, a feeding speed, an angle being half of the vertex angle of the pattern, and an imaging time, so as to correct an image forming position on the back side to coincide with an image on the front side. The detection signal from the sensor with a low operation speed is processed according to a method utilizing a shape feature and the like of the detection pattern, thereby precisely detecting the position of the paper in the feeding direction.