Printing Apparatus Ring Buffer Manages Sheet Spacing
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Solution Overview
Problem
Digital printing devices face challenges in achieving high printing speed for sheet-like recording media due to the need for precise positioning and spacing of print images, which is complicated by speed fluctuations and the requirement for gaps between sheets to prevent collisions or overlapping during transport.
Innovation Solution
The method involves structuring document print data page by page through a raster process, generating raster print data line by line and column by line, and using a ring memory system to store and manage print data, allowing for the insertion of blank lines to maintain precise positioning and printing accuracy without significant control changes, even during phases with no recording medium present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sheet spacing is increased to prevent collisions or overlapping during transport, then reliability of sheet handling is improved, but productivity deteriorates due to reduced printing speed
Solution Approach 1:
The system performs preliminary actions by pre-processing document print data into raster print data line by line and storing it in a buffer memory before actual printing occurs. This allows the printing system to be ready with pre-processed data, enabling faster response when sheets arrive and reducing the need for large safety gaps between sheets.
Solution Approach 2:
A buffer memory serves as an intermediary between data input and the printing unit. It stores raster print data temporarily and supplies data to the printing unit at the appropriate timing, decoupling the data processing speed from the sheet transport speed and enabling high-speed printing without requiring large sheet spacing.
2Productivity
If sheet spacing is reduced to increase printing speed, then productivity is improved, but manufacturing precision deteriorates due to difficulty in positioning print images precisely on each sheet
Solution Approach 1:
The system converts document print data to raster print data in advance and stores it in buffer memory with proper line sequencing. This preliminary data preparation ensures that when a sheet arrives at the printing unit, the corresponding print data is already ready and correctly positioned, maintaining precision even with reduced sheet spacing.
Solution Approach 2:
The system uses sheet detection means to detect the arrival of each sheet and provides feedback to the control unit. Based on this feedback, the control unit retrieves the appropriate raster print data from the buffer memory and supplies it to the printing unit at the correct timing, ensuring precise positioning despite high-speed operation and reduced sheet gaps.
3Manufacturing precision
If data is stored and managed in a buffer memory with blank line insertion, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The buffer memory is segmented into different storage areas: a first storage area for normal raster print data and a second storage area for blank lines. This segmentation allows the system to manage complex data sequences (including intermittent blank lines for sheet spacing) through simple, organized memory structures and straightforward control logic.
Data Source
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AI summary
For printing sheet-shaped recording media (2a...2c) page by page in a printing device (1a), the recording media (2a...2c) are successively fed one after the other to at least one point-by-point controllable printing unit (4a...4d) in a transport direction (A), each with a sheet-like distance (d) to a preceding recording media (2a...2c). In this process, - page-by-page structured document print data is subjected to a raster process in which row- and column-wise structured raster print data is generated, - a predetermined nominal number NA of lines is provided for the document print data of each page, and - the raster print data is successively stored line by line in a print data storage area (25) of an electronic memory (15a).In the memory (15a) a blank line memory area (32) is provided for a blank line not to be filled with print data, - the raster print data is successively read line by line from the print data memory area (25) of the memory (15a) and supplied to the printing unit (4a...4d) line by line, and - after each reading of the nominal number NA of lines from the print data memory area (25), the blank line memory area (32) is read a number of LZ times, where LZ is an integer greater than or equal to zero and depends on the sheet spacing (d).