Sheet Conveying Device Suction Timing for Crease Prevention
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Solution Overview
Problem
Existing image forming apparatuses face challenges in conveying sheets without creases or lifting, as the attraction and pressing mechanisms often fail to effectively grip the sheet along the entire circumference of the conveying drum, leading to instability and creases during the printing process.
Innovation Solution
A sheet conveying device comprising a conveying body, a pressing body, and an attracting device, where the attracting device includes an attracting unit with a suction mechanism that extends shorter than the distance between the pressing body and the operation start position, rotating with the conveying body to attract and stabilize the sheet on the drum, preventing creases and lifting by applying suction before the sheet passes the pressing point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the attracting device extends over the entire circumference of the conveying drum, then the sheet can be gripped uniformly, but the complexity of the device increases and the attraction timing becomes difficult to control precisely
Solution Approach 1:
The attracting device is divided into multiple attracting units arranged circumferentially on the conveying drum, with each unit having a limited extending length. This segmentation allows the device to achieve effective sheet gripping through coordinated operation of multiple units rather than requiring a single complex circumferential structure.
Solution Approach 2:
The attracting units are positioned to start attraction before the sheet reaches the pressing body, with the extending length configured to ensure attraction begins at the appropriate upstream position. This preliminary action ensures the sheet is properly gripped before pressing occurs, improving reliability without requiring full circumferential coverage.
2Reliability
If the attracting unit extends longer than the distance between the pressing body and the operation start position, then attraction begins earlier, but the sheet may be attracted too early causing instability and creases
Solution Approach 1:
The attracting units are configured with specific extending lengths that are shorter than the distance between the pressing body and the operation start position. This local quality control ensures attraction occurs at the precise appropriate location upstream, preventing both premature and delayed attraction, thereby maintaining sheet stability and smooth conveyance.
3Ease of operation
If the attracting unit extends shorter than the distance between the pressing body and the operation start position, then the sheet is attracted at the correct timing, but the gripping force may be insufficient
Solution Approach 1:
Multiple attracting units are arranged circumferentially on the conveying drum, with their extending lengths configured to be shorter than the distance between the pressing body and the operation start position. The combined gripping force of multiple units compensates for the limited extending length of each individual unit, ensuring sufficient total gripping force while maintaining precise attraction timing.
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 ensures stable sheet conveyance by preventing creases and lifting, allowing for smooth operation and improved image formation on the sheet, enhancing the overall printing process efficiency.
Implementation Method 1
The attracting device sucks and attracts the sheet onto the conveying body
Data Source
AI summary
A sheet conveying device includes a conveying body, a pressing body, and an attracting device. The conveying body conveys a sheet. The pressing body presses the sheet to a circumferential surface of the conveying body at an upstream side from an operation start position at which an operation with respect to the sheet starts, in a sheet conveying direction. The attracting device sucks and attracts the sheet onto the conveying body. The attracting device includes an attracting unit having an attracting region extending shorter than a distance between the pressing body and the operation start position. The attracting unit rotate together with the conveying body.