Sheet Discriminator Using VCSEL Array for Detection Accuracy
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Solution Overview
Problem
Existing sheet discriminators in image forming apparatuses face challenges in accurately detecting sheet types due to deformation issues, such as curl and waveform, which degrades discrimination accuracy, and the constant emission of light shortens the lifespan of optical sensors.
Innovation Solution
A sheet discriminator with a light emission controller that activates the light emitter only when detecting sheet information, using a VCSEL array and multiple receivers to differentiate between specular and diffused reflection light, and a sheet loading mechanism to prevent deformation detection, thereby extending sensor life and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light emitter constantly emits light to detect sheet information, then the detection accuracy is maintained, but the lifespan of the optical sensor shortens
Solution Approach 1:
The light emitter is controlled to emit light periodically rather than continuously. The light emission controller activates the light emitter only when a sheet is detected in the sheet conveying path, and stops emission when no sheet is present. This periodic operation maintains detection accuracy when needed while significantly extending the optical sensor's lifespan by reducing cumulative exposure time.
2Duration of action of stationary object
If the light emitter is activated only when needed, then the sensor lifespan is extended, but the detection response time may increase
Solution Approach 1:
The system performs preliminary detection to determine whether a sheet is present in the conveying path before activating the light emitter for detailed sheet type discrimination. This preliminary check ensures the light emitter is activated only when necessary, minimizing response time delay while extending sensor lifespan by avoiding unnecessary emission during periods when no sheet is present.
3Ease of operation
If sheet deformation is allowed during conveyance, then the sheet handling is simpler, but the discrimination accuracy degrades
Solution Approach 1:
The sheet discriminator is positioned and configured to detect sheets at a location where deformation effects are minimized. The detection point is selected to be equidistant from potential deformation sources such as feed rollers and conveyance paths, ensuring that sheets are measured in a relatively stable state without requiring complex deformation prevention mechanisms.
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
Enhances the accuracy of sheet type discrimination while extending the life of optical sensors by optimizing light emission and reducing energy consumption.
Implementation Method 1
The sheet discriminator causes the light emitting element of the optical sensor to emit light and the light receiving element of the optical sensor to receive the light reflected on a surface of the sheet traveling in the sheet conveying path
Implementation Method 2
using a VCSEL array and multiple receivers to differentiate between specular and diffused reflection light
Implementation Method 3
using a VCSEL array and multiple receivers to differentiate between specular and diffused reflection light
Data Source
AI summary
A sheet discriminator, which is incorporated in an image forming apparatus and an image forming system, includes a sheet loader on which a recording medium is loaded, an information detector including a light emitter to emit light to a surface of the recording medium loaded on the sheet loader and a light receiver to receive the light emitted by the light emitter and detecting information of the recording medium, a sheet distinguisher to distinguish a type of the recording medium based on the information detected by the information detector, and a light emission controller to control activation and stop of the light emitter and activate the light emitter before the information detector starts detection of the information of the recording medium.