Image Forming Apparatus Lubricant Control via Coverage-Based Toner Ejection
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Solution Overview
Problem
Existing image forming apparatuses face issues with unnecessary toner consumption and reduction of lubricant on image bearing members during low-coverage image formation processes, leading to inefficient use of resources and potential cleaning performance degradation.
Innovation Solution
An image forming apparatus that computes the time average coverage of toner images for different time periods and controls the formation of a toner image pattern for forcible toner ejection on the image bearing member, ensuring lubricant supply is optimized and unnecessary toner consumption is minimized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a toner image of a pattern for forcible toner ejection is formed in a non-image forming region to supply additional toner mixed with lubricant to the developing device, then the lubricant in the developing device can be prevented from being exhausted, but unnecessary toner consumption increases
Solution Approach 1:
The patent changes the parameter of toner ejection timing from continuous to conditional based on coverage rate detection. When the coverage rate is below a predetermined threshold, the system triggers forcible toner ejection by forming a toner image pattern in the non-image forming region. This parameter-based control ensures lubricant supply stability only when necessary, preventing unnecessary toner consumption during normal operation.
Solution Approach 2:
The patent implements a feedback mechanism where the coverage rate of the image to be formed is detected and used to control whether forcible toner ejection should occur. The control section receives coverage rate information, compares it with a predetermined threshold, and adjusts the toner ejection action accordingly. This feedback loop prevents unnecessary toner consumption while ensuring lubricant supply when needed.
2Productivity
If continuous low-coverage image formation is performed, then productivity is maintained, but the lubricant in the developing device is exhausted and cleaning performance degrades
Solution Approach 1:
The patent applies preliminary action by detecting the coverage rate before image formation and proactively triggering forcible toner ejection when low coverage is predicted. This prevents lubricant exhaustion before it occurs, maintaining cleaning performance while allowing continuous low-coverage image formation to proceed. The toner image pattern is formed in advance in the non-image forming region to replenish lubricant before the developing device runs out.
3Loss of substance
If no forcible toner ejection is performed during low-coverage image formation, then unnecessary toner consumption is avoided, but the lubricant on the photoconductor is reduced and cleaning performance deteriorates
Solution Approach 1:
The patent changes the operational parameter from no forcible ejection to conditional forcible ejection based on coverage rate. By detecting when coverage falls below a threshold, the system selectively activates toner ejection only when necessary, balancing toner consumption with cleaning performance requirements.
Solution Approach 2:
The system uses feedback from coverage rate detection to control forcible toner ejection. When the detected coverage rate indicates low toner-lubricant transfer, the control section activates the toner ejection mechanism. This feedback-based control prevents both unnecessary toner consumption and lubricant depletion, maintaining optimal cleaning performance.
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 prevents the reduction of lubricant on the image bearing member and limits unnecessary toner consumption, ensuring efficient image formation without wasteful toner use, thereby maintaining cleaning performance and resource efficiency.
Implementation Method 1
irradiate (expose) a charged photoconductor with (to) laser light based on image data to form an electrostatic latent image on the surface of the photoconductor
Implementation Method 2
toner mixed with lubricant is applied to attach the lubricant on the surface of the photoconductor
Implementation Method 3
the toner image is directly or indirectly transferred to a sheet, followed by heating and pressurization, whereby an image is formed on the sheet
Data Source
AI summary
An image forming apparatus includes: an image bearing member on which a toner image is formed; an image forming section configured to form the toner image by attaching toner mixed with lubricant to the image bearing member, and transfer the toner image formed on the image bearing member to a sheet; a computing section configured to compute a time average value of a coverage of the toner image transferred to the sheet by the image forming section for each of a plurality of different time periods; and a control section configured to control the image forming section to form a toner image of a pattern for forcible toner ejection on the image bearing member in accordance with a result of computing of the computing section.