Web Buffer Control for Printing Speed Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing printing systems face challenges in maintaining consistent print quality and productivity due to variations in conveyance speed caused by differences in process speed between printing apparatuses and post-processing machines, leading to increased costs and defective products in high-mix small-lot production.
Innovation Solution
A printing system with a conveyance mechanism, a print medium buffer, and control units that calculate and adjust conveyance speed based on predicted consumption amounts to synchronize with post-processing machine processing times, reducing the need for manual intervention and minimizing speed variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the printing apparatus and post-processing machine are directly connected in-line, then automation and consistency are improved, but speed mismatch causes print quality degradation and productivity loss
Solution Approach 1:
A web buffer is introduced as an intermediary device between the printing apparatus and post-processing machine group. The web buffer temporarily stores printed print paper, allowing the printing apparatus to operate at its optimal speed while the post-processing machine processes at its own pace. This mediator absorbs the speed mismatch and enables consistent in-line operation without compromising print quality.
Solution Approach 2:
The conveyance speed of the print paper is dynamically adjusted based on the predicted consumption amount of the web buffer. When the buffer is predicted to be full, the conveyance speed is reduced; when space is available, the speed is increased. This parameter change enables the system to maintain optimal printing speed while preventing buffer overflow, thus preserving print quality consistency.
2Stability of the object's composition
If a web buffer is provided to absorb speed difference, then process speed mismatch is reduced, but buffer capacity requirements increase cost
Solution Approach 1:
The system calculates the predicted consumption amount of the web buffer in advance based on job information and current buffer usage. This preliminary prediction allows the control unit to proactively adjust the conveyance speed before the buffer becomes full, rather than reacting after overflow occurs. This prevents the need for excessively large buffer capacities.
Solution Approach 2:
The control unit continuously monitors the actual consumption amount of the web buffer and compares it with the predicted consumption amount. Based on this feedback, the conveyance speed is dynamically adjusted. This closed-loop control optimizes buffer usage and prevents overflow without requiring excessive buffer capacity.
3Reliability
If conveyance speed is frequently adjusted to match post-processing speed, then buffer overflow is prevented, but print quality and productivity decrease
Solution Approach 1:
The system performs preliminary calculation of the predicted consumption amount of the web buffer based on job information before actual buffer overflow occurs. This allows the conveyance speed to be adjusted in advance, preventing overflow without the need for frequent reactive speed changes that would disrupt printing throughput and compromise print quality.
Solution Approach 2:
Instead of continuously adjusting the conveyance speed to exactly match post-processing speed, the system uses a threshold-based approach. The conveyance speed is adjusted only when the predicted consumption amount exceeds a predetermined threshold, allowing the buffer to operate with some excess capacity rather than constant fine-tuning, thus maintaining productivity.
Data Source
AI summary
A printing system, including a printing apparatus that sends a print paper after printing to a post-processing machine and a web buffer that temporarily holds a print paper after printing, is provided with: a required print time calculation unit that calculates a required print time for each job; an increase and decrease amount calculation unit that calculates an increase and decrease amount of a consumption amount of the buffer per set for each job on the basis of a difference between a minimum processing time required for a process in a post-processing machine and the required print time; a predicted value calculation unit that obtains a predicted value of the consumption amount of the web buffer by accumulating increase and decrease amounts; and a conveyance control unit that controls a conveyance speed of print paper on the basis of the predicted value.