Sheet Humidification Roller Water Supply Control
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Solution Overview
Problem
Existing sheet humidification systems using pairs of humidification members with a height difference cause uneven humidification, leading to sheet curl and other issues like static electricity and heat-related problems during thermal fixation processes in electrophotographic image forming apparatuses.
Innovation Solution
A control system that adjusts the water supply to humidification members based on their vertical positioning, calculating and modifying the water supply amounts to account for water movement between rollers, ensuring equal humidification on both sides of the sheet by controlling the depth of water supply rollers and draining sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is supplied equally to both upper and lower humidification rollers, then the water supply amount is simplified, but water moves from the upper roller to the lower roller causing uneven humidification and sheet curl
Solution Approach 1:
The patent applies local quality by supplying different water amounts to the upper and lower humidification rollers based on their specific positions and water movement characteristics. The lower roller receives less water supply to compensate for water moving down from the upper roller, creating localized quality adjustment that achieves uniform humidification across the sheet surface.
Solution Approach 2:
The patent changes the water supply parameter differently for each roller. Specifically, it reduces the water supply amount to the lower humidification roller compared to the upper roller, adjusting this parameter based on the vertical height difference and water movement between rollers to maintain uniform humidification.
2Device complexity
If humidification rollers are disposed at the same height, then water distribution is simplified, but they cannot be applied to rollers disposed on upper and lower sides for horizontal sheet conveyance
Solution Approach 1:
The patent employs asymmetry by positioning the humidification rollers at different vertical heights rather than the same level. This asymmetric arrangement allows the system to handle horizontal sheet conveyance effectively, with the upper and lower rollers positioned to sandwich the sheet during transport while accounting for gravitational water movement.
3Quantity of substance
If water supply amount is increased to compensate for water movement, then humidification amount increases, but energy consumption and water usage increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and adjusting the water supply amounts to upper and lower rollers based on predicted water movement. Instead of adding excess water and then removing it, the system proactively supplies the precise amount needed to each roller, preventing water waste and reducing energy consumption while achieving the required humidification level.
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 effectively reduces the difference in humidification amounts between the upper and lower surfaces of the sheet, preventing curling and improving the stability and smooth operation of the sheet handling process.
Implementation Method 1
a pair of humidification members 225a, 225b configured to humidify a sheet while sandwiching the sheet
Implementation Method 2
movement of the water from the upper humidification roller to the lower humidification roller is caused at the timing when the upper and lower humidification rollers make contact with each other
Data Source
AI summary
A sheet humidification apparatus includes a pair of humidification rollers, a water supply section, and a control section configured to control humidification of the humidification rollers and water supply of the water supply section, and the control section refers to a contacting period between the humidification rollers to control the water supply such that a second water supply amount from the water supply section to the second humidification member is smaller than a first water supply amount from the water supply section to the first humidification member.