Intermediate Transfer Belt Speed Control for Color Registration
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Solution Overview
Problem
Image formation apparatuses with tandem image formation units face challenges in accurately superimposing colors due to belt speed variations, leading to color dislocation issues, especially when the belt becomes slack during operation.
Innovation Solution
The apparatus initializes the rotation of photoconductive drums downstream along the belt, with the belt rotating faster than the drum, and applies a bias voltage to a transfer roller to maintain tension, ensuring immediate slack uptake and accurate color alignment through controlled speed differences and voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photoconductive drum is in close contact with the belt to reduce speed variations, then belt speed stability is improved, but slack in the belt cannot be taken up immediately after activation
Solution Approach 1:
The patent reverses the conventional speed relationship between the belt and photoconductive drum. Instead of the drum rotating faster than the belt (as in conventional technology), the belt is made to rotate faster than the drum. This speed difference creates a natural mechanism where the belt pulls the drum along, allowing immediate uptake of slack while maintaining stable speed through the frictional drive relationship.
2Loss of time
If the belt rotates faster than the photoconductive drum, then slack is taken up immediately, but the photoconductive drum must be driven by friction which may reduce torque transmission
Solution Approach 1:
The system uses the frictional drive relationship to make the belt self-regulating. The belt's faster rotation automatically creates the necessary friction to drive the drum without additional mechanical coupling. The system self-adjusts to maintain optimal frictional contact, taking up slack immediately while transmitting sufficient torque through the frictional interface between belt and drum surface.
3Manufacturing precision
If color dislocation correction and belt speed correction are performed using toner patches, then image alignment is improved, but the corrected state is disturbed when belt slack varies during use
Solution Approach 1:
The patent implements preliminary action by establishing the correct speed relationship between belt and drum at the start of operation. The belt is made to rotate faster than the drum from the beginning, which proactively prevents slack from developing during operation. This preliminary speed differential ensures that the belt remains taut throughout use, maintaining the stability of the corrected color alignment without requiring repeated corrections.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for immediate slack correction and maintains high-quality image formation by ensuring accurate color alignment and stable belt tension, preventing color dislocation and maintaining image quality over time.
Implementation Method 1
the photoconductive drum is in close contact with the belt. This makes the photoconductive drum that is in close contact with the belt rotate as if it were driven by the belt. As a result, torque of each photoconductive drum is applied to the belt
Implementation Method 2
application of a bias voltage to the transfer roller may be started and not stopped thereafter
Data Source
AI summary
In a printer 10 provided with image formation units 60a to 60d arranged in tandem so as to be in contact with an intermediate transfer belt 52 that is stretched taut between a driving roller 53 and driven rollers 56a to 56c, the intermediate transfer belt 52 moves at speed Vb, the circumference of a photoconductive drum 61 of each of the image formation units 60a to 60d moves at speed Vd, and Vb and Vd are so set as to be Vb>Vd. When the printer 10 is activated, after the intermediate transfer belt 52 starts to rotate, the photoconductive drums 61 start to rotate one after the next starting with the one disposed most downstream along the rotation direction of the intermediate transfer belt 52.