Pressure Roll Flare Control in Print Fusers
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Solution Overview
Problem
Fuser roll flare in print apparatuses changes unpredictably due to thermal differentials, leading to insufficient flare at the start of print jobs, causing wrinkling, and excessive flare during jobs, resulting in image smearing.
Innovation Solution
A pressure roll cooling device is used to maintain consistent flare by cooling the inside and outside paper path portions of the pressure roll, controlled by temperature sensors to regulate thermal expansion and prevent excessive flare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the pressure roll is flared to reduce wrinkling of media sheets, then wrinkle control is improved, but image smear occurs due to excessive flare
Solution Approach 1:
The pressure roll is designed with different flare characteristics at different locations: the inside paper path portion has a first flare value while the outside paper path portion has a second flare value. This local differentiation allows the inside portion to provide sufficient tentering force for wrinkle control while the outside portion limits excessive flare that would cause image smear.
Solution Approach 2:
The pressure roll is segmented into distinct functional zones: an inside paper path portion and an outside paper path portion, each with independently controlled flare properties. This segmentation enables independent optimization of each zone's flare characteristics to achieve both wrinkle control and image quality preservation.
2Stability of the object's composition
If the pressure roll flare changes during print job operation, then thermal differential effects are reduced, but unpredictable flare variation occurs between standby and steady state
Solution Approach 1:
The pressure roll is pre-cooled before the print job begins, establishing a known initial temperature state and flare characteristic. This preliminary cooling action ensures that the pressure roll starts in a controlled state, making the flare predictable at the beginning of operation before thermal differentials can cause unexpected variations.
Solution Approach 2:
The temperature of the pressure roll is actively controlled and changed during operation. By adjusting the temperature parameter of the pressure roll, the system maintains consistent flare characteristics throughout the print job, preventing unpredictable flare variation while reducing thermal differential effects.
3Shape
If the inside paper path portion is cooled to maintain flare, then wrinkle control is improved, but the cooling system complexity increases
Solution Approach 1:
The pressure roll cooling device is designed to cool the pressure roll using the existing cooling infrastructure of the printing system. The cooling device utilizes available cold air or cooling elements already present in the apparatus, eliminating the need for a separate, dedicated cooling system and thereby reducing overall device complexity.
Solution Approach 2:
The cooling device serves multiple functions: it cools the pressure roll to maintain consistent flare for wrinkle control, and it can be integrated with other cooling functions already present in the printing system. This multi-functionality reduces the need for additional specialized cooling components, thereby reducing system complexity.
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 solution ensures consistent pressure roll flare, reducing media sheet wrinkling and image smearing by maintaining a stable temperature difference between the inside and outside paper paths, thereby improving print quality.
Implementation Method 1
controlled by temperature sensors to regulate thermal expansion and prevent excessive flare
Implementation Method 2
This solution ensures consistent pressure roll flare, reducing media sheet wrinkling and image smearing by maintaining a stable temperature difference between the inside and outside paper paths
Data Source
AI summary
An apparatus and method that control pressure roll flare in a print apparatus. The apparatus can include a fuser having a fuser surface. The apparatus can include at least one heat source configured to heat the fuser surface. The apparatus can include a pressure roll having a pressure roll surface, the pressure roll having a rotational axis, the pressure roll having an inside paper path portion towards the middle of the pressure roll along the rotational axis and having an outside paper path portion near at least one end of the pressure roll along the rotational axis, the pressure roll coupled to the fuser at a fuser nip, where the fuser nip is configured to fuse marking material on a media sheet. The apparatus can include a pressure roll cooling device configured to cool at least one of the inside paper path portion and the outside paper path portion of the pressure roll to maintain substantially consistent pressure roll flare prior to media sheets entering the fuser nip and while media sheets pass through the fuser nip to provide wrinkle control of media sheets while limiting image smear of the marking material on the media sheets.