Printing Apparatus Sheet Standby Positioning for Image Quality
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Solution Overview
Problem
Printing apparatuses face issues with sheet curvature during long standby times, leading to image quality deterioration, especially with glossy paper, due to the nipping action of conveying rollers, which causes warping of the ink accepting layer and gloss unevenness.
Innovation Solution
The printing apparatus employs a dual standby position system for the sheet front end, where the first standby position is outside the image area to prevent warping, and the second standby position is closer to the print start for efficient conveyance, allowing for borderless printing and reducing sheet nipping effects, along with ink non-ejection detection and ink tank management to maintain image quality and prevent jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet is nipped by conveying rollers during long standby time, then the sheet can be held in position, but the sheet becomes curved and image quality deteriorates
Solution Approach 1:
The patent implements dynamic switching between two standby positions based on operational conditions. The first standby position places the sheet front end outside the image area to prevent warping during extended standby, while the second standby position places it at the print start position for rapid printing resumption. This dynamic adaptation resolves the contradiction between maintaining sheet stability and preventing curvature-induced image quality deterioration.
Solution Approach 2:
The system changes the positional parameter of the sheet front end between two discrete locations depending on whether printing operations are active or in standby mode. By adjusting this positional parameter dynamically, the system maintains both reliable sheet positioning and prevents curvature that would degrade image quality during long standby periods.
2Productivity
If the sheet front end is positioned at the print start position during standby, then printing can start quickly, but the sheet may warp due to nipping
Solution Approach 1:
The system dynamically selects the standby position based on operational context. When printing operations are anticipated or in progress, the second standby position (print start position) is used for rapid resumption. When extended standby is expected, the system switches to the first standby position (outside image area) to prevent warping. This dynamic behavior maintains both productivity and image quality.
Solution Approach 2:
The system performs preliminary positioning of the sheet to the appropriate standby position based on predicted operational needs. By anticipating whether rapid printing resumption or extended standby is required, the system pre-positions the sheet accordingly, preventing warping before it occurs while maintaining readiness for quick printing when needed.
3Manufacturing precision
If the sheet is pulled back frequently to prevent warping, then image quality is maintained, but processing time increases
Solution Approach 1:
Rather than frequently adjusting sheet position, the system dynamically selects between two standby positions based on the duration and nature of standby periods. This eliminates the need for frequent pull-back operations while maintaining image quality, as the appropriate position is selected in advance based on operational context.
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 effectively reduces sheet curvature and maintains image quality by positioning the sheet front end outside the image area during standby, minimizing the impact of nipping on image quality and reducing processing time between prints, while preventing jams and nozzle clogging.
Implementation Method 1
a platen which sucks a sheet on the platen to prevent it from floating
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
A continuous sheet (1) is conveyed in a first direction in a printing operation, cut with a cutter (16) in a cutting operation, and then conveyed in a second direction opposite to the first direction. A conveyance amount of the continuous sheet (1) in the second direction is changed based on an operation of the printing apparatus after the cutting operation.