Sheet Storage Dehumidification Control for Wrinkle Prevention
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Solution Overview
Problem
Image forming apparatuses face issues with sheets adhering to each other due to high humidity, leading to overlapped feeding and misfeeding, as existing dehumidification techniques either unevenly reduce moisture content or fail to control it effectively, resulting in wrinkles.
Innovation Solution
An image forming apparatus with a sheet storage portion, a heater that heats air, and a fan that sprays heated air, controlled by a controller that adjusts the heater temperature and fan operation to maintain a balanced moisture content, preventing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a sheet is continuously dehumidified by heat generated by the heater, then the moisture content is reduced, but the moisture content is reduced only in a part of the sheet, causing wrinkles
Solution Approach 1:
The heater operates intermittently rather than continuously. The control unit turns the heater on and off periodically, allowing heat to be applied in cycles. This periodic heating action enables more uniform moisture distribution across the sheet by preventing localized overheating while still achieving overall dehumidification.
Solution Approach 2:
The sheet is subjected to preliminary dehumidification treatment before it reaches the fixing nip. By applying heat and reducing moisture content in advance, the sheet is prepared to avoid expansion or contraction issues that would occur if dehumidification happened during the fixing process.
2Reliability
If temperature and humidity of air are controlled to prevent reduction in sheet loosening performance, then sheet loosening is maintained, but moisture content of sheet is not controlled
Solution Approach 1:
A moisture sensor detects the moisture content of the sheet and provides feedback to the control unit. Based on this feedback, the control unit adjusts the heater operation to maintain appropriate moisture levels. This closed-loop control ensures both sheet loosening performance and moisture content are managed effectively.
Solution Approach 2:
The system changes the temperature and humidity parameters of the air in the sheet storage portion by operating the heater and fan. These parameter changes create conditions that prevent sheet adhesion while the moisture sensor ensures the sheet's moisture content remains within acceptable ranges.
3Quantity of substance
If sheets are stacked under high humidity environment, then sheets are adhered to each other, but friction separating system cannot prevent overlapped feeding or misfeeding
Solution Approach 1:
The mechanical friction-based separating system is supplemented or replaced by a thermal field approach. Instead of relying solely on friction between sheets, the system uses heat from the heater to control moisture content and reduce adhesion, creating a non-mechanical method for preventing sheet sticking.
Solution Approach 2:
The system changes the temperature and humidity parameters in the sheet storage portion by operating the heater and fan. These parameter changes reduce the adhesion between sheets caused by high humidity, enabling reliable sheet separation without relying solely on friction-based mechanical systems.
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
The solution effectively suppresses partial moisture reduction in sheets, thereby preventing wrinkles and ensuring smooth feeding by controlling the heater temperature and fan operation based on set thresholds and environmental conditions.
Implementation Method 1
a heater which heats air
Implementation Method 2
a fan which sprays air on the sheet stored in the sheet storage portion
Data Source
AI summary
An image forming apparatus including a sheet storage portion in which a plurality of sheets is stored; a heater which heats air; a fan which sprays air on the sheet stored in the sheet storage portion; and a controller which controls the heat of the heater and controls the drive of the fan, in which the controller controls the heat of the heater at a first temperature before a drive time of the fan reaches a threshold value set in advance, the drive time being in which the fan sprays air heated by the heater on the sheet, and when the drive time of the fan reaches or exceeds the threshold value set in advance, controls the heat of the heater at a second temperature lower than the first temperature.