Dynamic Suction Control for Sheet Transport Stability
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Solution Overview
Problem
Deformations in print media within printing systems, such as inkjet printers, lead to reliability issues, print quality degradation, and sheet jams due to the close proximity of the sheet transport mechanism and image forming devices, and existing solutions struggle to accurately adjust suction pressure to accommodate varying sheet delivery rates and defects.
Innovation Solution
A transport mechanism with a conveyor body and suction means, controlled by a controller that adjusts under-pressure based on the rate of sheet delivery and estimated future coverage, using sensors to detect defects and regulate fan speed to prevent deformation and optimize energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If under-pressure or suction is increased to hold sheets firmly on the conveyor body, then sheet holding stability is improved, but sheet deformation (cockling) increases due to excessive pressure
Solution Approach 1:
The suction fan speed is dynamically adjusted based on real-time detection of sheet delivery rate and conveyor body coverage. The controller modifies the suction pressure to match the actual number of sheets on the conveyor, preventing both excessive suction (causing cockling) and insufficient suction (causing sheet detachment).
Solution Approach 2:
The system uses sensors to detect the delivery rate of sheets and the coverage of the conveyor body, feeding this information back to the controller. The controller then adjusts the suction fan speed accordingly, creating a closed-loop control system that maintains optimal suction pressure and prevents sheet deformation.
2Reliability
If suction fan operates at high speed continuously to ensure adequate holding, then sheet holding is reliable, but energy consumption and noise increase
Solution Approach 1:
The suction fan operates at variable speeds rather than continuous high speed. The controller adjusts the fan speed dynamically based on the detected sheet delivery rate and conveyor coverage, consuming only the necessary amount of energy to maintain reliable sheet holding under different operating conditions.
Solution Approach 2:
The system changes the operational parameters (suction fan speed) based on the actual number of sheets on the conveyor body. When fewer sheets are present, the fan speed is reduced, optimizing energy consumption while maintaining adequate holding force.
3Manufacturing precision
If suction pressure is increased to prevent sheet deformation, then print quality is improved, but sheet jams increase due to excessive suction on defective sheets
Solution Approach 1:
The system continuously monitors sheet delivery rate and conveyor coverage, providing feedback to the controller. When a sheet is not delivered on time or the coverage changes unexpectedly, the controller reduces suction pressure, preventing excessive suction that could cause jams on defective sheets while maintaining print quality for normal operation.
Solution Approach 2:
The system prepares for potential sheet defects by continuously monitoring delivery rates and adjusting suction pressure in advance. When irregularities are detected, the suction is reduced beforehand to prevent jams, cushioning against the potential harm of defective sheets.
4Device complexity
If the transport mechanism operates with fixed suction pressure, then system complexity is reduced, but productivity decreases due to inability to adapt to varying sheet delivery rates
Solution Approach 1:
The controller receives feedback from sensors detecting sheet delivery rate and conveyor coverage, automatically adjusting suction pressure without requiring complex manual intervention. This automated feedback-based control maintains relatively simple system architecture while enabling adaptive operation that improves productivity.
Solution Approach 2:
The transport mechanism self-adjusts its suction pressure based on detected conditions, with the controller automatically modifying fan speed in response to sheet delivery variations. This self-service capability eliminates the need for complex external control systems while maintaining high productivity.
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 effectively prevents sheet deformation, reduces noise and energy consumption, extends fan lifespan, and ensures high print quality by accurately matching suction pressure to sheet delivery changes and detecting defects, thereby enhancing productivity and print quality.
Implementation Method 1
suction means, especially fan means, for generating an under-pressure at or adjacent to the conveyor body to hold the plurality of sheets fixed in position thereon
Data Source
AI summary
The invention provides a printing system with a transport mechanism for transporting sheets. The transport mechanism comprises: a conveyor body for supporting and conveying a plurality of sheets a transport path; suction means, and especially fan means, for generating an under-pressure at or adjacent to the conveyor body to hold the sheets fixed in position on the conveyor body as it conveys the plurality of sheets along the transport path; and a controller for controlling or regulating operation of the suction means to adjust the under-pressure generated. The controller is configured to control operation of the suction means based on delivery of the plurality of sheets to the conveyor body and/or a change in the delivery of the sheets to the conveyor body. Further, the invention provides a corresponding method of transporting sheets of a print medium in a printing system.