Image Memory Transfer Rate Control for First Copy Output Time
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Solution Overview
Problem
In image forming apparatuses that read both sides of an original, the First Copy Output Time (FCOT) is prolonged due to the potential mismatch between the transfer rate of image data from the image memory and the reading sensors, leading to a delay in image formation and increased user wait time.
Innovation Solution
The apparatus employs a dual-transfer rate strategy, starting with a lower transfer rate for the initial page and switching to a higher rate for subsequent pages, allowing for efficient data transfer without compromising reading throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transfer rate for image data from image memory is increased to improve reading throughput, then reading throughput is improved, but the FCOT becomes longer due to delay in image formation start timing
Solution Approach 1:
The patent applies dynamics by making the transfer rate variable rather than fixed. The transfer rate is dynamically adjusted based on the page number being transferred: a first (lower) transfer rate is used for the first page, and a second (higher) transfer rate is used for subsequent pages. This dynamic adjustment resolves the contradiction by optimizing the transfer rate according to the specific stage of operation.
Solution Approach 2:
The patent changes the parameter of transfer rate based on the page number. Specifically, the transfer rate parameter is set to a first value for the first page and a second value (higher than the first) for the second page and subsequent pages. This parameter change allows the system to prioritize FCOT reduction for the first page while maximizing throughput for subsequent pages.
2Productivity
If the transfer rate is set to a higher rate from the beginning, then reading throughput is maximized, but the start timing for image formation is delayed
Solution Approach 1:
The patent segments the image data transfer process into two distinct phases: transfer of the first page and transfer of subsequent pages. Each phase uses a different transfer rate optimized for its specific requirements. This segmentation allows the system to optimize for image formation start speed during the first page transfer while maximizing reading throughput during subsequent page transfers.
Solution Approach 2:
The transfer rate is dynamically changed based on the page number being transferred. The system transitions from a first transfer rate for the first page to a second (higher) transfer rate for subsequent pages. This dynamic adjustment enables the system to balance between quick start of image formation and high throughput reading.
Data Source
AI summary
An image forming apparatus temporarily stores, in an image memory, image data generated by a front surface reading unit and a back surface reading unit for reading images of a front surface and a back surface of an original respectively. A CPU of an image forming apparatus, at a time of starting a copy job, sets an output frequency of the image memory (transfer rate of image data) to a first frequency F1 that is lower than a second frequency F2. The CPU sets the output frequency of the image memory to the second frequency F2 when transfer of the image data of the first page which corresponds to the front surface of a first original completes.