Image Forming Apparatus Transfer Member Speed Control
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Solution Overview
Problem
Image forming apparatuses face issues with surface speed differences between rotatable members, leading to decreased image quality due to variations in parts and environmental conditions, which existing technologies have not adequately addressed.
Innovation Solution
An image forming apparatus that includes a hardware processor to set a target speed for a second rotatable member based on speed changes between separated and pressed states, ensuring synchronized surface speeds between the first and second rotatable members through constant-speed and constant-torque control mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the transfer member is controlled to rotate at a constant speed, then the transfer member can maintain stable rotation, but the torque applied to the image carrier changes on a cycle of passing sheets causing speed variations and color shifts
Solution Approach 1:
The patent applies dynamics by switching from static constant-speed control to dynamic constant-torque control. The transfer member's rotation is controlled based on detected torque values, allowing the system to adapt to changing load conditions (sheet presence/absence) while maintaining reliable image formation. This dynamic adjustment resolves the contradiction by prioritizing torque stability over speed constancy.
Solution Approach 2:
The patent implements feedback control by detecting the torque applied to the transfer member during rotation and using this information to control the rotation. The torque detection mechanism provides real-time feedback that enables the system to adjust rotation characteristics based on actual operating conditions, preventing speed variations that would cause color shifts while maintaining image formation accuracy.
2Stability of the object's composition
If a torque limiter is used to regulate driving force, then fluctuations of loads on the image carrier can be reduced, but the limiter value may not be set when the load on the transfer member greatly changes over time or due to environment
Solution Approach 1:
The patent replaces the fixed torque limiter approach with a feedback-based torque detection and control system. By continuously detecting the actual torque applied to the transfer member and using this information for control, the system automatically adapts to changing load conditions (time-based wear, environmental changes) without requiring manual reconfiguration of limiter values. This feedback mechanism simultaneously maintains load stability and provides adaptability.
Solution Approach 2:
The patent changes the control parameter from fixed torque limitation to dynamic torque detection and adjustment. Instead of relying on a predetermined torque limiter value that becomes obsolete under changing conditions, the system detects actual torque parameters in real-time and adjusts control based on these changing parameters, enabling both stability and adaptability.
3Speed
If constant-speed control is used for both transfer member and image carrier, then they can rotate at constant speeds, but surface speed differences due to variation in outer diameters and thicknesses cause shear in transferred images
Solution Approach 1:
The patent applies feedback control by detecting the torque applied to the transfer member during rotation and using this information to control the rotation. This torque-based feedback enables dynamic adjustment of the transfer member's rotation characteristics to compensate for surface speed differences caused by manufacturing variations in outer diameters and thicknesses, thereby preventing shear in transferred images while maintaining constant rotation speeds.
Solution Approach 2:
The patent substitutes mechanical precision (relying on exact matching of outer diameters and thicknesses) with a control system based on torque detection. Instead of requiring mechanically perfect components to achieve synchronized surface speeds, the system uses torque feedback to electronically compensate for mechanical variations, achieving image transfer accuracy without stringent mechanical tolerances.
Data Source
AI summary
An image forming apparatus includes: a first rotatable member; a second rotatable member that presses against the first rotatable member in a pressed state and separates from the first rotatable member in a separated state; and a hardware processor that sets a target speed of the second rotatable member based on a change in speed of the second rotatable member between a first speed in the separated state and a second speed in the pressed state.