Image-Forming Gear Pre-Meshing for Quieter Print Starts
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Solution Overview
Problem
Conventional image-forming apparatuses experience abnormal noise and delayed gear meshing due to the movable gear moving from the second position to the first position when printing starts, which can be disruptive.
Innovation Solution
The image-forming apparatus incorporates a controller that waits for a print command after completing a connection process where the movable gear is meshed with the first gear, using a switching mechanism to manage gear transitions, thereby suppressing noise by ensuring the gear is already engaged before printing begins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the movable gear moves from the second position to the first position when printing starts, then the gear can transmit drive force to the sheet-feeding device, but abnormal noise occurs and the gear meshing is delayed
Solution Approach 1:
The movable gear is moved to the first position and meshed with the follow gear before the print command is received, during the connection process. This preliminary action ensures that the gear transmission mechanism is already prepared and can immediately transmit drive force when printing starts, eliminating the delay and abnormal noise that would occur if the gear meshed at the moment of printing start
2Reliability
If the movable gear moves from the second position to the first position when printing starts, then the gear transmission can be established, but it takes time for the gear to move and mesh
Solution Approach 1:
The gear transmission mechanism is prepared in advance by moving the movable gear to the first position and meshing it with the follow gear during the connection process, before the print command is received. This eliminates the time loss that would occur if the gear had to move and mesh at the moment of printing start, ensuring immediate transmission readiness
3Object-affected harmful factors
If the controller waits for a print command with the movable gear already meshed with the first gear, then noise is suppressed, but the system requires an additional connection process
Solution Approach 1:
The movable gear is moved to the first position and meshed with the follow gear during the connection process, which is performed once during startup. This preliminary meshing eliminates abnormal noise during printing operations without requiring continuous control interventions, as the gear remains engaged during the waiting period for print commands
4Productivity
If the movable gear is separated from the first gear during reverse rotation, then the drive force transmission is interrupted, but the gear cannot be positioned for quiet operation
Solution Approach 1:
The movable gear is designed to be dynamically positionable between the first position (meshed with follow gear for quiet operation) and the second position (meshed with first gear for drive force transmission). The switching mechanism enables the gear to transition between these positions based on operational requirements, allowing the system to optimize for either noise suppression or drive force transmission as needed
Data Source
AI summary
An image-forming apparatus includes: a motor; a transfer roller; a fixing device; a movable first cam; a first gear train including a first gear and a movable gear; a second gear train including a switching mechanism; and a controller. The fixing device includes a heat roller and a pressure roller providing a nip pressure therebetween. The controller is configured to perform: a first process for setting the nip pressure to a first nip pressure; a second process for setting the nip pressure to a second nip pressure lower than the first nip pressure; and a connection process for moving the movable gear to mesh with first gear. The controller is configured to wait for a print command in a state where the movable gear is meshed with the first gear by performing the connection process after completing the second process.