Rasterizer and Decompressor Coordination for Safe Job Cancellation
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Solution Overview
Problem
In printing apparatuses, when a job cancel request is inputted, the rendering processing module may stop without receiving pixel data from the image processing module, leading to untransmitted pixel data and incorrect rendering.
Innovation Solution
An image forming apparatus that includes a memory device for storing raster image data in a compressed format, a generator for intermediate data, and a decompressor that continues decompressing data even when stopping rendering processing, allowing safe cancellation of rendering based on decompressed data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rendering processing module stops when a job cancel request is received, then the productivity is improved by allowing quick cancellation, but the reliability deteriorates because untransmitted pixel data remains causing incorrect rendering
Solution Approach 1:
The system performs preliminary action by having the decompressor continue decompressing pixel data even after the rendering module stops processing. This ensures that all pixel data is fully decompressed and transmitted before the system considers the cancellation complete, preventing any untransmitted data from causing incorrect rendering in future operations.
2Reliability
If the decompressor continues decompressing data after rendering stops, then the reliability is improved by ensuring all data is transmitted, but the loss of time increases due to continued processing
Solution Approach 1:
The decompression process is allowed to complete as a preliminary action before the system fully transitions to the cancelled state. This ensures data integrity while the time overhead is accepted as necessary for reliable operation.
3Reliability
If the rendering module waits for all pixel data to be received before stopping, then the reliability is improved by ensuring complete data transmission, but the productivity deteriorates by delaying job cancellation
Solution Approach 1:
The system initiates the decompression of remaining pixel data as a preliminary action immediately when cancellation is requested, rather than waiting. This allows the cancellation process to begin promptly while the decompression completes in the background, achieving both responsiveness and completeness.
Solution Approach 2:
The decompressor continues its useful action of decompressing pixel data even after the rendering module stops. This continuous operation ensures that all data is transmitted without interrupting the decompression process, maintaining reliability while allowing the rendering module to respond quickly to cancellation requests.
Data Source
AI summary
An image forming apparatus stores raster image data corresponding to a background in a compressed format and generates intermediate data corresponding to a foreground of the background based on obtained print data. A decompressor decompresses the raster image data stored in the memory device and a rasterizer generates new raster image data based on the raster data corresponding to the background obtained by the decompression and the generated intermediate data corresponding to the foreground. When a request is made to stop the generation of the new raster image data in a state of waiting for at least a portion of the raster image data corresponding to the background to be decompressed, the rasterizer stops generation of the new raster image data, and the decompressor continues decompressing the at least a portion of the raster image data corresponding to the background.