Cam Rotation Control for Image Fixing Quality
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Solution Overview
Problem
Existing contact-separation mechanisms in image forming apparatuses face challenges in accurately controlling the rotation of cams to manage the pressurization and depressurization of rollers, leading to variations in the rotation stop position and potential issues with fixing quality due to changes in torque and operational conditions.
Innovation Solution
A contact-separation mechanism that includes a cam with a reference range, a detection target, and a detector, where the circuitry issues a rotation stop instruction based on the duration of the detection target passing through a detection area, allowing for precise control of the cam's rotation and minimizing variations in the rotation stop position by adjusting the target time based on the passing time of the detection target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cam rotation is controlled based on fixed time intervals, then the control is simple to implement, but the rotation stop position varies due to changes in rotational speed and torque
Solution Approach 1:
The patent employs feedback control by detecting the actual rotational position of the cam using a detector and comparing it with the target position. The control unit adjusts the motor drive time based on the detected position to ensure accurate stopping. This closed-loop feedback mechanism resolves the contradiction by maintaining position accuracy while keeping the control system relatively simple.
Solution Approach 2:
The patent replaces pure mechanical timing control with an integrated system that combines electrical motor control, optical detection, and computational adjustment. The detector uses optical fields to sense cam position, and the control unit processes this information to dynamically adjust motor operation, substituting rigid mechanical timing with flexible electronic control.
2Adaptability or versatility
If the cam rotates at variable speeds due to torque changes, then the mechanism can adapt to different operational conditions, but the rotation stop position becomes inconsistent
Solution Approach 1:
The feedback mechanism continuously monitors the cam's actual rotational position regardless of speed variations. The control unit receives real-time position data from the detector and adjusts the motor drive duration to compensate for speed changes, ensuring the cam stops at the correct position even when rotational speed varies due to torque changes or operational conditions.
Solution Approach 2:
The system dynamically adjusts the motor drive time based on real-time detection of cam position and rotational characteristics. Rather than using fixed timing, the control unit modifies operational parameters on-the-fly to maintain position accuracy under varying torque and speed conditions, embodying the dynamic adaptation principle.
3Manufacturing precision
If a detector and feedback control system is added to achieve precise rotation control, then the rotation stop position accuracy improves, but the device complexity increases
Solution Approach 1:
While feedback control does add components (detector, control unit), the patent integrates these into the existing cam mechanism in a compact manner. The detector is positioned to monitor cam rotation directly, and the control unit processes signals to adjust motor operation, achieving precise position control with minimal additional complexity.
Solution Approach 2:
The control unit serves multiple functions: it detects cam position, calculates required adjustments, determines optimal drive time, and controls motor operation. This multi-functionality reduces the need for separate dedicated components for each control task, thereby limiting the increase in overall device complexity while maintaining high position accuracy.
Data Source
AI summary
A contact-separation mechanism includes a cam to rotate to move a contact-separation member to and from a counterpart member, a detection target to rotate together with the cam, and a detector to detect presence or absence of the detection target in a detection area of the detector, and circuitry. The cam has a reference range. The circuitry issues a rotation stop instruction of the cam after a target time elapses from passing of the reference range of the detection target through the detection area, and sets the target time based on a duration of an immediately preceding passing of the reference range through the detection area.