Print Job Scheduling With Buffer Control for Sheet Ejection Order
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Solution Overview
Problem
Existing image forming apparatuses face inefficiencies due to differences in processing speeds between printing and post-processing, leading to temporary halts in printing and misordering of printed sheets when using a buffer device.
Innovation Solution
Incorporating a buffer device to stack printed sheets, a first ejection device for processed sheets, and a second ejection device for unprocessed sheets, with circuitry to calculate predicted printing and post-processing times, allowing for selective job execution based on these times to maintain efficient sheet ejection order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a buffer device is used to compensate for processing speed differences between printing and post-processing, then printing continuity is improved, but sheet ejection order may become disordered
Solution Approach 1:
The ejection system is segmented into two separate ejection devices: a first ejection device for sheets requiring post-processing and a second ejection device for sheets not requiring post-processing. This segmentation allows independent control of ejection timing for different sheet types, preventing order disintegration caused by buffer stacking while maintaining printing continuity.
Solution Approach 2:
The control device acts as an intermediary that receives print jobs, determines post-processing requirements, and routes sheets to appropriate ejection devices. It calculates predicted post-processing times and uses these predictions to coordinate ejection timing, ensuring sheets are ejected in the correct order even when buffer devices are used to maintain printing continuity.
2Manufacturing precision
If printing is stopped when the buffer reaches capacity, then sheet ejection order is maintained, but printing productivity decreases
Solution Approach 1:
The system dynamically adjusts printing operation based on buffer status and post-processing capacity. Instead of static stop-start printing, the control device continuously monitors buffer capacity and post-processing completion status, dynamically determining when to continue or pause printing to maintain sheet order while maximizing productivity.
Solution Approach 2:
The control device calculates predicted post-processing times in advance for each sheet and uses these predictions to proactively manage buffer capacity and printing pace. By knowing future post-processing completion times, the system can prevent buffer overflow before it occurs, maintaining sheet order without unnecessary printing interruptions.
3Productivity
If multiple print jobs are processed simultaneously, then overall productivity increases, but job execution scheduling becomes complex
Solution Approach 1:
The control device implements feedback mechanisms by continuously monitoring buffer capacity, post-processing status, and job queue state. It uses this feedback to dynamically adjust job execution scheduling, selecting which jobs to process next based on current system state and predicted outcomes, thereby managing multiple jobs efficiently without excessive complexity.
Solution Approach 2:
The system changes scheduling parameters dynamically based on job characteristics and system state. It calculates predicted printing times and predicted post-processing times for different jobs and uses these parameters to optimize job execution order, allowing multiple jobs to be processed simultaneously while maintaining simple and effective scheduling logic.
Data Source
AI summary
An image forming apparatus includes: a buffer device to stack a plurality of sheets, each sheet having been printed and to be applied with post-processing based on a first print job, and transmit a stop signal instructing to stop the first print job when the plurality of sheets stacked on the buffer device reaches a predetermined number; a first ejection device to eject the sheet having been printed and applied with the post-processing; a second ejection device to eject the sheet having been printed based on a second print job, the second print job being executed after the first print job is stopped; and circuitry to calculate a predicted printing time of each print job based on printing capability, calculate a predicted post-processing time of each print job based on post-processing capability, and select the second print job based on the predicted printing time and the predicted post-processing time.