Developing Roller Rotation Estimation via Motor Current Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image forming apparatuses, accurately estimating the rotation amount of a developing roller without a direct sensor is challenging due to mismatched rotation amounts between the drive source and the developing roller, and the addition of a sensor increases cost and space requirements.
Innovation Solution
A configuration that uses a brushless motor and a stepping motor with a drive switching unit and motor control circuit to estimate the developing roller's rotation amount by detecting current changes, eliminating the need for a sensor on the developing roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is added to directly detect the rotation amount of the developing roller, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a mediator (drive transmission switching unit and motor control circuit) that indirectly measures the developing roller's rotation amount by detecting the drive source's rotation and calculating the corresponding developing roller rotation based on transmission ratios, eliminating the need for direct sensors on the developing roller
Solution Approach 2:
The patent replaces the mechanical sensor-based detection system with an electrical control system that uses motor rotation detection and computational calculation to estimate the developing roller's rotation amount, thereby reducing mechanical complexity
2Measurement precision
If a sensor is disposed to detect the developing roller rotation, then measurement precision is improved, but the size of the product increases
Solution Approach 1:
The patent extracts the detection function from the developing roller assembly and relocates it to the drive source motor, eliminating the need for additional sensors and associated space in the product structure
Solution Approach 2:
The motor control circuit serves multiple functions: controlling the drive source motor rotation and simultaneously calculating the developing roller rotation amount, eliminating the need for separate detection components and reducing overall product size
3Productivity
If the unit for switching between drive and non-drive is provided in the drive transmission path, then productivity is improved by reducing total rotation amount, but measurement precision deteriorates due to mismatched rotation amounts
Solution Approach 1:
The patent implements a feedback mechanism where the motor control circuit continuously monitors the drive source rotation amount and uses this information to calculate and track the corresponding developing roller rotation amount, ensuring accurate measurement even with intermittent drive transmission
Solution Approach 2:
The patent performs preliminary calculation of the developing roller rotation amount based on the drive source rotation and transmission ratio before actual image formation occurs, allowing accurate tracking of roller usage even when the roller is not continuously rotating
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An image forming apparatus includes a developing roller, a motor, a motor control portion configured to control the motor, a drive switching unit configured to switch between transmission and non-transmission of the rotational driving force of the motor relative to the developing roller, a current detection portion configured to detect a current value of a current to the motor, and an acquisition unit configured to acquire information relating to a rotation amount of the developing roller. The acquisition unit is configured to acquire the information relating to the rotation amount of the developing roller on the basis of a transmission timing at which the rotational driving force is allowed to be transmitted to the developing roller by the drive switching unit and a non-transmission timing at which the rotational driving force is prevented from being transmitting to the developing roller by the drive switching unit.