Multifunction Printer Buffer Memory Segmentation and Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multifunction printers require large memory capacities and wide data access bands due to the need for extensive buffer memory and simultaneous access by multiple image processing units, leading to inefficiencies in both copy and scan modes, especially when dealing with high-resolution images.
Innovation Solution
The implementation of a multifunction printer with a copy image processing unit that compresses image data using DPCM compression only during the copy function, reducing the total memory size required and preventing image quality degradation during the scan function by utilizing a shading memory and DPCM decompression processing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If image data is stored in buffer memory for simultaneous access by multiple image processing units, then copy and scan functions can operate, but memory capacity and data access bandwidth increase significantly
Solution Approach 1:
The patent divides the buffer memory into multiple regions (first buffer region for scan mode, second buffer region for copy mode, third buffer region for intermediate storage) that are selectively activated based on operational mode. This segmentation allows the system to allocate memory efficiently for each specific function rather than maintaining large buffers for all functions simultaneously.
Solution Approach 2:
The patent implements dynamic buffer allocation where the memory configuration changes based on operational mode. The control unit selectively activates different buffer regions depending on whether scan mode or copy mode is operational, allowing the memory structure to adapt dynamically to current needs rather than maintaining a fixed large capacity.
2Ease of manufacture
If buffer memory capacity is reduced, then system cost decreases, but multiple image processing units cannot simultaneously access image data
Solution Approach 1:
The patent stores compressed image data in advance in the third buffer region after scanning but before copying. This preliminary compression and storage action allows the system to reduce peak memory requirements during copy operations, as the data is already prepared and compressed rather than requiring large buffers for uncompressed data manipulation.
Solution Approach 2:
The patent changes the data format parameter by compressing image data using DPCM compression before storage in the third buffer region. This parameter change from uncompressed to compressed format reduces the memory capacity required by approximately 50%, allowing cost-effective implementation while maintaining simultaneous access capability through selective buffer activation.
3Quantity of substance
If DPCM compression is applied to image data, then memory size required decreases, but image quality may be degraded
Solution Approach 1:
The patent applies different processing quality levels to different operational modes. In scan mode, uncompressed data is maintained for high quality output to external devices. In copy mode, compressed data is acceptable as it is for internal reproduction. This local quality differentiation allows compression where acceptable (copy mode) while preserving quality where required (scan mode).
Solution Approach 2:
The patent creates a compressed copy of the image data for storage in the third buffer region, while the original uncompressed data remains available in the first or second buffer regions. This copying approach allows the system to use compressed data for copy operations (reducing memory requirements) while preserving the original high-quality data for scan operations.
4Productivity
If wide data access bandwidth is provided, then multiple image processing units can access data simultaneously, but system complexity and cost increase
Solution Approach 1:
The patent segments the data access paths to different buffer regions, allowing controlled access rather than requiring all processing units to access a single large buffer simultaneously. This segmentation reduces the peak bandwidth requirements on any single data bus while maintaining overall system productivity through coordinated access to specialized buffer regions.
Solution Approach 2:
The patent implements dynamic control of data access through the control unit, which manages which buffer regions are active and coordinates access timing. This dynamic control allows efficient use of available bandwidth without requiring excessive peak bandwidth capacity, reducing bus complexity while maintaining productivity through intelligent resource management.
Data Source
AI summary
This invention relates to an MFP having copy and scanner functions. The MFP in which image data flows from a line sensor to a DRAM via an A/D conversion unit and a reading control unit (RCU) and then from an image processing unit (IPU) to a printer via the DRAM has the following arrangement. Both the RCU and the IPU can execute a shading process. In the CM, the RCU executes the shading process. Then, the image is compressed and stored in the DRAM. In the SM, the RCU does not execute the shading process, and the image is temporarily stored in the DRAM without compression. The IPU reads out image data of each rectangle from the DRAM together with shading data, executes the shading process and various kinds of image processing, and outputs the image data to the DRAM.