Fixing Unit Nip Deformation Control via Dynamic State Switching
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Solution Overview
Problem
In image forming apparatuses, the separation of fixing members after a predetermined time can lead to increased first copy output time (FCOT) due to the need for a preparation operation to change from a separated to a contact state, causing delays in image formation.
Innovation Solution
The apparatus determines its state at a predetermined time point and controls the fixing device accordingly, executing a rotation operation in the first power mode and a separation operation in the second power mode to optimize power usage and prevent image formation delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fixing member and pressing member are separated after a predetermined time to prevent deformation, then image quality is improved, but the first copy output time increases due to preparation operation
Solution Approach 1:
The fixing device dynamically changes its state based on operational conditions. When a job is received, the fixing member and pressing member are brought into contact; when no job is received for a predetermined time, they are separated. This dynamic state change prevents deformation while minimizing impact on FCOT through conditional execution.
Solution Approach 2:
The system changes the operational parameter of the fixing device (contact vs. separated state) based on the predetermined time condition. This parameter change prevents deformation of the fixing nip portion while the control logic optimizes when to execute the change to minimize FCOT impact.
2Productivity
If the fixing member and pressing member remain in contact to reduce first copy output time, then productivity is improved, but deformation of the fixing nip portion occurs causing image failure
Solution Approach 1:
The fixing device performs periodic contact and separation operations based on job reception timing. The contact state is maintained during image formation for productivity, then separated after a predetermined time to prevent deformation, creating a periodic cycle of contact-separation-contact that balances both requirements.
Solution Approach 2:
The control unit monitors job reception status and time elapsed since last operation to determine when to separate or contact the fixing members. This feedback mechanism ensures separation occurs only when appropriate (after predetermined time without jobs) to prevent deformation while minimizing impact on FCOT.
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
This approach reduces FCOT by minimizing the preparation time required for image formation and prevents deformation of the fixing nip portion, ensuring efficient operation and image quality.
Implementation Method 1
fix onto the sheet the toner image transferred by the transfer unit with a pressing force of the nip portion while applying heat via the first rotary member
Data Source
AI summary
An image forming apparatus including a normal power mode and a power saving mode includes a fixing unit configured to bring first and second rotary members into contact with each other to form a nip portion and fix a toner image onto a sheet with a pressing force of the nip portion. The image forming apparatus executes a rotation operation or a separation operation to separate the first and second rotary members from each other in order to prevent a deformation of the nip portion in the fixing unit. The image forming apparatus measures a time during which the first and second rotary members are in contact with each other without rotating. The image forming apparatus determines whether to execute the separation operation or the rotation operation based on a result of the power mode determination and the measured time.