Motor Control Sheet Detection Without Sensors
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Solution Overview
Problem
Conventional image forming apparatuses require additional sensors for detecting sheets in the conveyance path, increasing the size and cost of the equipment.
Innovation Solution
A sheet conveyance apparatus that uses a motor control system with phase feedback control to determine the rotational phase of a rotor and adjust the drive current, allowing for sheet detection without sensors by analyzing the load torque applied to the rotor during a predetermined drive period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is provided for detecting a sheet in the conveyance path, then sheet detection accuracy is improved, but the apparatus size and cost increase
Solution Approach 1:
The motor serves dual functions: driving the conveyance roller and detecting sheet presence through its own operational parameters. The detection unit utilizes the motor's rotational phase and current consumption data to determine whether a sheet is present in the conveyance path, eliminating the need for separate detection sensors.
Solution Approach 2:
The system continuously monitors the motor's rotational phase and current consumption during operation, using this feedback information to detect sheet presence. The control unit adjusts the motor drive based on detected conditions, creating a closed-loop system that achieves detection without additional sensors.
2Reliability
If additional sensors are installed for sheet detection, then detection capability is improved, but manufacturing cost increases
Solution Approach 1:
The motor is designed to perform multiple functions: it drives the conveyance roller during normal operation and simultaneously serves as a detection device by monitoring its rotational phase and current consumption. This multi-functionality eliminates the need for separate detection components, reducing manufacturing cost while maintaining detection capability.
Solution Approach 2:
The detection function is merged with the motor control system. The control unit integrates sheet detection capabilities into the existing motor drive circuitry, combining the drive and detection functions into a single integrated system that reduces component count and manufacturing complexity.
3Productivity
If the conveyance roller is driven at high speed, then productivity is improved, but detection accuracy of sheet presence deteriorates
Solution Approach 1:
The system performs detection at specific periodic intervals during motor operation. The control unit monitors the motor's rotational phase and current consumption at predetermined timing points, allowing accurate detection even during high-speed conveyance by sampling at optimal moments in the rotational cycle.
Solution Approach 2:
The system performs a preliminary detection phase before normal high-speed conveyance begins. During this preliminary phase, the motor is driven at a controlled speed to establish baseline rotational phase and current consumption characteristics, which are then used to detect sheet presence during subsequent high-speed operation.
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 detection of sheets in the conveyance path without increasing the apparatus size or cost, improving operational efficiency and reducing expenses.
Implementation Method 1
a motor control apparatus that controls a motor (M2) for driving a conveyance roller (13)
Data Source
AI summary
A sheet conveyance apparatus includes a stacking unit having a sheet, a feeding unit, a conveyance roller to convey a sheet fed by the feeding unit, a motor to drive the conveyance roller, a phase determiner, first and second controllers, and a discriminator. The feeding unit feeds the sheet. The phase determiner determines a motor rotor rotational phase. The first controller controls a drive current flowing in a motor winding to reduce a deviation between an instructed phase of the motor rotor and the determined rotational phase. The second controller controls to perform a first drive for driving the conveyance roller for a predetermined time before a feeding unit feed operation is started. The discriminator discriminates presence or absence of the sheet at a nip portion of the conveyance roller based on a value of a parameter corresponding to load torque applied to the rotor during the first drive.