Motor Drive Current Sheet Type Discrimination
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Solution Overview
Problem
Existing image forming apparatuses require a sensor to determine the type of recording medium, leading to increased size and cost due to the need for additional space and installation costs.
Innovation Solution
An image forming apparatus that determines the type of sheet without using a sensor, utilizing a motor control system with a phase determiner, controller, current detector, and discriminator to detect the drive current and determine the sheet type based on the current values during conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is installed in the conveyance path to determine sheet type, then the sheet type determination accuracy is improved, but the apparatus size and manufacturing cost increase
Solution Approach 1:
The motor serves dual functions: it conveys the sheet through the apparatus and simultaneously provides sheet type information through its current consumption pattern. The control unit analyzes the current waveform during sheet conveyance to determine sheet type, eliminating the need for separate sensing mechanisms. This self-service approach allows the existing motor to provide both mechanical and diagnostic functions.
Solution Approach 2:
The patent replaces the mechanical/optical sensor-based detection system with an electrical measurement system. Instead of using physical sensors in the conveyance path, the system uses electrical current measurements from the motor drive to infer sheet type. This substitution eliminates the need for additional mechanical components while maintaining determination accuracy.
2Reliability
If a sensor is installed to detect sheet type, then the image forming quality is improved through optimized settings, but the installation cost and space requirements increase
Solution Approach 1:
The system implements feedback by continuously monitoring the motor's current consumption during sheet conveyance. The control unit analyzes the current waveform characteristics to determine sheet type, then uses this information to optimize image forming parameters such as transfer voltage and fixing temperature. This closed-loop feedback mechanism ensures high image quality without requiring physical sensors in the conveyance path.
Solution Approach 2:
The motor control system performs multiple functions: it drives the conveyance rollers to move sheets through the apparatus and simultaneously acts as a sensing system for sheet type detection. By making the motor multi-functional, the system achieves reliable sheet type determination for optimized image forming without adding separate detection hardware, thereby reducing manufacturing complexity and cost.
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
Enables accurate determination of sheet type without the need for a sensor, reducing the apparatus's size and cost while maintaining effective image forming capabilities.
Implementation Method 1
a phase determiner configured to determine a rotation phase of a rotor of the motor
Implementation Method 2
a current detector configured to detect the drive current flowing through the winding
Implementation Method 3
a motor configured to drive the first roller
Data Source
AI summary
An image forming apparatus includes an image forming unit to form an image on a sheet, first and second rollers, a motor, a phase determiner, a controller, a current detector, and a discriminator. The motor drives the first roller which conveys the sheet. The second roller is downstream from the first roller. The phase determiner determines a rotation phase of a rotor of the motor. The controller controls a drive current flowing through a motor winding to reduce a deviation between a command phase representing a rotor target phase and the determined rotation phase. The current detector detects the drive current flowing through the winding. The discriminator determines a type of the sheet conveyed by the first roller based on a value of the drive current detected in a state in which the sheet is deflected while being conveyed by the first roller and not conveyed by the second roller.