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Agenda. Introduction 12:00 Ozone Fan/Filter Assembly 12:15 Monitoring Charge on Photoconductor 12:30 LED Exposure System 12:45 Paper Delivery System 1:00 High Visibility Warning Signs 1:15 Camera System 1:30 Transfer Roller Speed Measurement 1:45 Labview Control Interface 2:00
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Agenda • Introduction 12:00 • Ozone Fan/Filter Assembly 12:15 • Monitoring Charge on Photoconductor 12:30 • LED Exposure System 12:45 • Paper Delivery System 1:00 • High Visibility Warning Signs 1:15 • Camera System 1:30 • Transfer Roller Speed Measurement 1:45 • Labview Control Interface 2:00 • Additional Issues 2:15
Detailed Design ReviewP09503 – Electrophotographic Development and Transfer Station Friday, October 31, 2008 12:00PM-3:00PM 76-A120
Introduction to Electrophotography • Electrophotography is base technology used in modern day copy printers • Six Step Process • Charging • Exposure • Development • Transfer • Fusing • Cleaning • EDTS only includes first four
Project Introduction • EDTS will contribute to understanding of current EP technology • Manipulation of input parameters • Objective is to take existing EDTS and • Make it functional • Improve Usability • Automate Control of Machine • Additional Performance Improvements
Project Deliverables • 1 – An inventory and status of current sub-systems, including needed support systems. • 2 – A working EDTS. • 3 – Demonstrably improved device safety. • 4 – An improved user interface (includes control and display functions) • 5 – Device documented for use, maintenance and upgrade of the device (User & Lab Technician Manual) • 6 – Demonstrably Improved Sensing and Control Subsystem
System Level Overview • Photoconductor • Hold Photosensitive Material • Photosensitive Material • Increased conductivity during exposure to light • Traverse EDTS • Interact Photosensitive Material with • Charge • Discharge • Development • Transfer
System Level Overview • Charging • Establish an electrical field within the area of the Photoconductor • Photoconductor passes at very small distance • Corona • Wires subjected to up to 10,000 Volts • Grid • Distribute charge of corona
System Level Overview • Exposure • Expose Photosensitive material to light • Reduce charge on exposed areas • Electrostatic latent image remains
System Level Overview • Development • Deposit charged toner particles onto charged areas of photosensitive material • Magnetic Developer creates a “wall” of toner and developer
System Level Overview • Transfer • Transfer toner from photosensitive material to paper • Transfer Drum is Charged • Two Steps • Toner to Transfer Drum • Transfer Drum to Paper
System Level Functional Diagram • Functional Diagram shows areas for improvement
Customer Needs • 1. Is Operational • 2. Is Safe • 3. Minimizes user intervention during Charging • 4. Minimizes user intervention during Discharge • 5. Minimizes user intervention during Development • 6. Minimizes user intervention during Transfer • 7. Minimizes user intervention during maintenance • 8. Can monitor key process parameters • 9. Automation of Parameter Settings • 10. Can operate and monitor machine from one interface • 11. Easy to learn to use • 12. Areas for system upgrades are identified and documentation for upgrade procedures available where applicable • 13. Maintenance of system is documented • 14. Both drawings and Bills of Materials document device • 15. Operation of Device Is Documented • 16. Toner clean up • 17. Inventory and Status Report of current systems • 18. Vary charging voltage • 19. Vary charging current • 20. Vary exposure • 21. Can accommodate different toner materials • 22. Vary development voltage • 23. Vary development current • 24. Can use multiple toner stations • 25. Vary transfer voltage • 26. Vary transfer current • 27. Improve exposure subsystem • 28. Monitor charge of the Photoconductor • 29. Incorporate other manufacturers development systems • 30. Paper delivery system Ability to accommodate different types of media
Engineering Specifications • Please see documentation
Ozone Fan/Filter Assembly Phil Lopez
Description • Reduce and Secure Ozone Test Stand • Ozone hazardous to humans if exposed to enough • Law states maximum ozone in A/C Space is 0.05 ppm [1] • >0.200 ppm increases risk of health issues [1] • Two Options • Verify current system or • Implementation of further improvement to control Ozone Levels [1] http://www.ozoneservices.com/articles/007.htm
Ozone Customer Needs Satisfied and Associated Specifications
Proof of Concept • Measure ozone at various locations to determine if measurements are within limits • Test/Experimental – TBD due to insufficient equipment = Test Areas
Proof of Concept • Set values • 0-1.0 kV at increments of 0.1 kV for Grid and Corona • 1-10kV at increments of 0.5 kV for Grid and Corona • Will Measure • Ozone Produced without Fan • Ozone Produced with Fan • At original height and two inches higher
Proof of Concept • Material Selected Al 2024 • Stress found to be ~520 psi • Less than Yield Stress of 45ksi • Less than Ultimate Stress of 65ksi
Monitoring the Charge on Photoconductor Min-Shi Hsiao
Description • Output quality determined by functionality of each subsystem • Monitoring charge of photosensitive material will help characterize exposure input noise source • Can also help create charge v. exposure plot after measurement • Measuring device is Trek 344 Electrostatic Volt Meter (ESVM) • Probe functions like capacitor that charges up to same level as object being measured
Drawings/Schematics • Probe must be placed 2mm from PC surface • Cannot be held by hand • Could result in short or shock • Position should be fixed during measurement • Existing Camera Mounts used • Allows for easy adjustment • Intermediate probe mount needed to attach probe to camera mount
Proof of Concept • Mylar used for testing instead of PC Material • Mylar not sensitive to light, no exposure necessary • Mylar glued to PC plate and driven down EDTS • Begin with 500 Volts at charging • Measurements taken after charging and exposure
LED Exposure System Rachel Chrash
Description • LED Print Heads used in copiers and printers to expose Photosensitive Material are commonly used • LED Exposure system to replace current incandescent system • Advantages • More versatile and reliable light source • Low Power Consumption • Longer Bulb Life • No potential for overheat • Inexpensive to replace
Current System vs. LED System • Current System • Incandescent light uses collimating lens to collect light and direct toward image plane • LED System • Provide more direct source of light to image plane
Relative Intensity vs. Wavelength • Plot shows intensity, or relative spectral power distribution w.r.t. wavelenth • PC Material most sensitive to blue light which has shortest wavelength • Explains why system can be successfully operated in yellow light without large impact on PC exposure
Proof of Concept • Most successful exposure results in even light distribution across entire image plane • Three light sources tested using Gossen PanLUX Analog Lux Meter • LUX = intensity (lumen/m2) • Grid constructed over image plane at level where exposure takes place • Light intensity and uniformity measured every 1x1 inch • Pinpoint measurements were then taken of the current system • 2x2 LED Array • 2x3 LED Array
Mounting System • Array can be contained inside projector casing • Located at bottom or • Located on Small Shelf at height TBD by testing • Larger than 3x3 array could pose issue due to size • Modify Projector Case
Paper Delivery System Ruth Gay