Developing Roller Contact Failure Detection via Motor Torque
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses consume toner to detect failures in developing roller and photosensitive member contact/separation mechanisms, leading to unnecessary toner consumption.
Innovation Solution
An image forming apparatus that includes a control portion to detect failures in contact/separation mechanisms by monitoring torque changes of the photosensitive-member motor, determining abnormal states based on predetermined torque values and timing differences, and providing notifications when specific conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If test patterns are formed on photosensitive members to detect contact/separation mechanism failures, then detection capability is improved, but toner consumption increases
Solution Approach 1:
The patent replaces the optical/mechanical test pattern formation method with an electrical measurement method. Instead of forming test patterns and using sensors to detect them, the system measures torque changes of the photosensitive-member motor during rotation. This substitution eliminates the need for toner consumption while maintaining detection capability through electrical parameter monitoring.
Solution Approach 2:
The patent introduces torque as an intermediary parameter to detect contact/separation mechanism failures. Rather than directly observing the mechanical contact state or using toner-based test patterns, the system uses torque changes of the motor as an indirect indicator of abnormal contact conditions, enabling failure detection without toner consumption.
2Productivity
If developing rollers and photosensitive members are brought into contact during operation, then image formation is enabled, but excessive sliding friction occurs when one rotates and the other does not
Solution Approach 1:
The patent implements feedback control by continuously monitoring torque changes of the photosensitive-member motor during rotation. When abnormal contact between the developing roller and photosensitive member is detected through torque analysis, the system can respond by adjusting operational parameters or alerting operators, preventing excessive sliding friction and potential damage.
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
The solution allows for detecting failures in contact/separation mechanisms while significantly reducing toner consumption, thereby extending the service life of developing rollers and photosensitive members.
Implementation Method 1
a control portion configured to determine that the contact/separation mechanism is in a failure state in a case where a torque of the photosensitive-member motor is not detected to have changed by at least a predetermined value within a predetermined time after a predetermined reference timing
Data Source
AI summary
An image forming apparatus includes a photosensitive member; a developing roller; a contact/separation mechanism configured to switch between a contact state in which the developing roller is brought into contact with the photosensitive member and a separation state in which the developing roller is separated from the photosensitive member; a photosensitive-member motor configured to rotate and drive the photosensitive member; and a control portion. The control portion is configured to determine that the contact/separation mechanism is in a failure state in a case where a torque of the photosensitive-member motor is not detected to have changed by at least a predetermined value within a predetermined time after a predetermined reference timing.