Variable Speed Printing Control for Image Reproduction Devices
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Solution Overview
Problem
Existing image reproduction devices face inefficiencies in productivity due to the inability to smoothly and flexibly control processing speeds without affecting document quality, leading to mechanical stress, noise, and reduced productivity, especially when switching between different operational conditions or handling varying sheet types.
Innovation Solution
A control unit that gradually adjusts the processing speed of the sheet conveying system and digital imaging unit within a range of speeds in response to changing operational conditions, allowing continuous operation without compromising document quality, and enabling seamless speed changes without mechanical shocks or quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the processing speed is switched instantaneously between different speeds, then the productivity can be improved by faster processing, but the sheets will be torn or wrinkled due to accelerations or decelerations
Solution Approach 1:
The patent applies dynamics by enabling the sheet conveying system and digital imaging unit to operate at any one of a plurality of processing speeds rather than being fixed at a single speed. The control unit dynamically adjusts the processing speed based on operational conditions, allowing the system to adapt between high-speed processing and speed adjustments while maintaining sheet integrity through controlled transitions.
Solution Approach 2:
The patent changes the parameter of processing speed from a fixed value to a variable parameter that can take any one of a plurality of speeds. The control unit modifies this parameter in response to changing operational conditions, enabling the system to optimize productivity while maintaining reliability by controlling the magnitude and duration of speed changes.
2Reliability
If the processing speed is changed after emptying the sheet trajectories, then the sheet integrity is maintained, but the time is lost and productivity decreases
Solution Approach 1:
The patent applies preliminary action by having the control unit prepare for speed changes in advance. The system can detect operational conditions and initiate speed adjustments before the sheet trajectories are completely empty, reducing the waiting time while maintaining sheet integrity. This allows the system to optimize both reliability and productivity by planning speed changes strategically.
Solution Approach 2:
The patent maintains continuity of useful action by enabling the sheet conveying system and digital imaging unit to operate continuously at variable speeds without requiring complete stopping or emptying of trajectories between speed changes. The control unit manages continuous operation across multiple speeds, eliminating idle time and maintaining productive activity while preserving sheet integrity through controlled speed transitions.
3Productivity
If the processing speed is increased to handle more sheets, then the productivity is improved, but the mechanical stress and noise increase
Solution Approach 1:
The patent applies dynamics by enabling the system to operate at any one of a plurality of processing speeds rather than being fixed at maximum speed. The control unit dynamically adjusts the processing speed based on the number of sheets to be processed and operational conditions, allowing the system to optimize between productivity and mechanical stress/noise by selecting appropriate speeds for different workloads.
Solution Approach 2:
The patent applies partial action by processing sheets at variable speeds rather than consistently at maximum speed. The control unit selects appropriate processing speeds based on the specific operational conditions and number of sheets, using higher speeds only when necessary and reducing speeds when mechanical stress or noise becomes excessive, thus achieving optimal balance between productivity and harmful factors.
Data Source
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AI summary
An image reproduction device for document processing is described. Although the device has a nominal processing speed (47) at which it can process sheets continuously at a nominal document quality, it is arranged for processing sheets at a continuously variable processing speed including the nominal processing speed, the actual processing speed being selected in dependence of operational conditions. In particular, the device is arranged for gradually adjusting the processing speed (46) from one processing speed to another processing speed. A control structure is given for selecting the variable processing speed in dependence of operational conditions, and for operating the image reproduction device at the selected processing speed. In a particular application of the variable speed, a print job may be started at an increased processing speed (45) and then gradually fall back to the nominal speed (47), giving a fast start and a shorter processing time for short print jobs.