Print Controller Queue Scheduling for Waste Reduction
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Solution Overview
Problem
Current high-speed production printing systems face significant paper waste when scheduling high priority print jobs, as immediately clearing print data paths to accommodate them often leads to a 'back hitch' condition, causing unintended blank pages and printer downtime.
Innovation Solution
The print controller checks if the last queue has sufficient data before initiating a high priority print job, partially clearing intermediate queues while allowing the last queue to complete, thus avoiding the back hitch condition and minimizing paper waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the print data path is immediately cleared to accommodate a high priority print job, then the high priority job can begin processing sooner, but the queues are emptied causing a back hitch condition and significant paper waste
Solution Approach 1:
The patent applies partial action by selectively clearing only the intermediate queues (segmenter queue, layout master queue, rasterizer queue) while preserving the last queue data. This partial clearing approach allows the high priority job to advance through the print data path without completely emptying all queues, thereby avoiding the back hitch condition that causes paper waste while still enabling faster processing of the high priority job.
2Loss of time
If the print data path is cleared to make room for high priority print job, then the high priority job can be processed without delay, but the print engine stops printing causing downtime
Solution Approach 1:
The patent segments the print data path into multiple distinct queues: intermediate queues (segmenter queue, layout master queue, rasterizer queue) and the last queue that directly feeds the print engine. This segmentation allows selective clearing of only the intermediate queues while preserving data in the last queue, enabling the print engine to continue operating without interruption while still accommodating the high priority job.
3Productivity
If all queues are emptied to accommodate high priority job, then the high priority job starts immediately, but unintended blank pages are produced
Solution Approach 1:
The patent applies partial action by selectively clearing only the intermediate queues (segmenter queue, layout master queue, rasterizer queue) while preserving the last queue data. This partial clearing approach allows the high priority job to advance through the print data path without completely emptying all queues, thereby avoiding the back hitch condition that causes blank pages while still enabling faster processing of the high priority job.
Data Source
AI summary
Systems and methods are provided for scheduling high priority print jobs with minimal paper waste. One embodiment is a printing system that includes a print controller having a print data path with intermediate queues and a last queue to store print ready bitmap data. The print controller monitors the last queue to determine an estimate time for printing the print ready bitmap data stored in the last queue, determines whether the estimate time exceeds a time threshold, and determines whether a high priority print job is detected in the job storage system. In response to determining that the estimate time exceeds the time threshold and detecting the high priority print job, the print controller halts processing of at least one of the plurality of print jobs that is not the high priority print job, and advances processing of the high priority print job on the print data path.