Duplex Printing Machine Sheet Turnover Mechanism
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Solution Overview
Problem
Existing electro-photographic sheet of paper duplex printing machines face inefficiencies in duplex printing due to prolonged processing times, unstable top and bottom register alignment, high costs, and significant temperature fluctuations in the fixing device, leading to reduced print efficiency and product quality.
Innovation Solution
The electro-photographic sheet of paper duplex printing machine incorporates a sheet positioning section with suction conveyers and registration rollers for accurate sheet positioning, a chain delivery system with a temporary fixing device, and a sheet carrying section for turnover with a drop auxiliary mechanism to ensure stable sheet handling and orthogonal positioning, reducing processing time and maintaining consistent temperature in the fixing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the one side printed sheet is turned over by reciprocating through a switching path, then the sheet can be inverted for duplex printing, but only one sheet at most is permitted in the switchback path causing carrying interval to be lengthened and print efficiency to be reduced
Solution Approach 1:
The sheet carrying system is divided into multiple independent carrying paths (first carrying path and second carrying path) that can operate simultaneously. The sheet turnover carrying section can carry sheets in one direction while the sheet supply section feeds sheets in the opposite direction, enabling parallel processing and eliminating the bottleneck of single-path reciprocating carrying.
2Loss of time
If the one side printed sheet is dropped onto the sheet carrying section during carrying operation, then the sheet can be turned over quickly, but the register of top and bottom of the sheet becomes unstable causing misalignment
Solution Approach 1:
A sheet turnover carrying section is introduced as an intermediary device between the sheet supply section and the fixing device. This dedicated turnover section provides a controlled environment for sheet inversion with proper support and positioning mechanisms, ensuring that sheets maintain stable register alignment during the turnover process while still achieving quick sheet changeover.
3Reliability
If the space in carrying direction between dropped sheets is made wide to prevent piling up, then sheets can be handled individually, but the interval between sheets must be widened reducing print efficiency
Solution Approach 1:
Instead of increasing the spacing in the carrying direction (one dimension), the system uses multiple carrying paths operating in opposite directions. This transforms the problem from a one-dimensional spacing issue to a two-dimensional parallel processing solution, allowing sheets to be handled individually without increasing the carrying interval and maintaining high print efficiency.
4Adaptability or versatility
If individual temporary fixing devices are arranged at two places for sheet turnover and delivery, then sheet handling can be performed independently, but the cost and setting space become large
Solution Approach 1:
The sheet turnover carrying section is designed with multi-functionality, serving both as a sheet inversion mechanism and as a carrying path for inverted sheets. The same structural components perform multiple functions (carrying, turning over, and positioning sheets), eliminating the need for separate dedicated devices for each function and reducing overall device complexity and cost.
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 configuration enables efficient duplex printing with stable top and bottom register alignment, reduced costs, and minimized temperature changes in the fixing device, thereby enhancing print efficiency and product quality.
Implementation Method 1
a suction conveyer carrying the sheet at a constant speed
Data Source
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AI summary
An electro-photographic sheet of paper duplex printing machine is disclosed in which there are fewer temperature changes of the fixing device at the time of printing, the duplex printing can be efficiently performed and its setting space can be reduced. The proposed electro-photographic sheet of paper duplex printing machine comprises a sheet supply section 2, a sheet positioning section 3 which positions the sheets 2b and sends out the sheets to a backup roller 41 in an electro-photographic printing section 4, the electro-photographic printing section 4 transfers an image which has been transferred onto the transfer roller onto the sheet, a chain delivery section 5, a delivery section 6 and a sheet carrying section for turnover 7. The chain delivery section 5 selectively transfers printed sheets 2b which has been transferred from the backup roller 40 to the delivery section 6 or the sheet carrying section for turnover 7. The sheet carrying section for turnover 7 supplies the one side printed sheet 2b to the sheet positioning section 3. The sheet 2b fed from the sheet supply section 2 and the one side printed sheet 2b fed from the sheet carrying section for turnover 7 are alternately carried to the sheet positioning section 3 and the toner image on the printed sheet 2b is fixed by the fixing device 6a.