Agenda • • • Introduction Ozone Fan/Filter Assembly Monitoring Charge on Photoconductor LED Exposure System Paper Delivery System High Visibility Warning Signs Camera System Transfer Roller Speed Measurement Labview Control Interface Additional Issues 12: 00 12: 15 12: 30 12: 45 1: 00 1: 15 1: 30 1: 45 2: 00 2: 15
Detailed Design Review P 09503 – Electrophotographic Development and Transfer Station Friday, October 31, 2008 12: 00 PM-3: 00 PM 76 -A 120
Team Members Name Discipline Role Email David Schwartz ISE Team Lead – Warning Signs drs 8889@rit. edu Ruth Gay ME Paper Delivery System rip 4474@rit. edu Phillip Lopez ME Ozone Filter pml 6464@rit. edu Dan Summers ME ME Support dcs 5083@rit. edu Rachel Chrash EE LED Exposure System rec 0678@rit. edu Min-Shi Hsiao EE PC Voltage Measurement mxh 7790@rit. edu Andrew Kearns EE Transfer Drum Speed Measurement, Camera System amk 0477@rit. edu Sasha Oliver User Interface aas 1878@rit. edu CE
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 Customer Need Satisfied Specification Ideal Value Marginal Value Is Safe Amount of Ozone Present in Air 0. 001 ppm 0. 050 ppm Maintenance of System is Documented Number of screws needed to detach ozone filter for removal and cleaning 4 4
Current System
Current Mount
New Mount (If Necessary)
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
Proof of Concept • Set values – 0 -1. 0 k. V at increments of 0. 1 k. V for Grid and Corona – 1 -10 k. V at increments of 0. 5 k. V 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 45 ksi Less than Ultimate Stress of 65 ksi
Bill of Materials Item Price Lead Time Supplier Sheet of Al 2024 $97 Available Mc. Master
Risk Assessment Description of Possible Probability of Severity of Risk Consequences Risk (H/M/L) Loose Fan Particulate Build Up or Clogging Ozone over EPA regulations Power Loss to Ozone over Fan EPA regulations Ozone Unable to Measurement measure Device Ozone levels Overall Risk (H/M/L) Contingency Plan M H M Reattach M H M Examine and do required maintenance M H L N/A L H M Not Available
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
Customer Needs Satisfied and Associated Specifications Customer Need Satisfied Specification Ideal Value Marginal Value 1. 20: Monitor key process parameter Charge on photoconductor after charging same as the applied voltage +/- 10% of the ideal value Charge on photoconductor after discharge (exposure) Proportional to the exposure level +/- 10% of the ideal value 2. 5 dpi +/- 0. 254 1. 70: Monitor charge of Measurement the Photoconductor resolution
Drawings/Schematics • Probe must be placed 2 mm 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
Probe
Current Camera Mounts
Intermediate Mount
Current Camera Mount with Probe Fixture
Location of Measurements
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
Risk Assessment Description of Risk Possible Consequences Manually moving the brick Electric shock Probability of Risk (H/M/L) L Severity of Risk (H/M/L) H Overall Risk (H/M/L) L Contingency Plan Avoid contact when machine is powered, user manual, warning sign, wear insulating gloves
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
Customer Needs Satisfied and Associated Specifications Customer Need Satisfied 3. 2: Improve exposure subsystem Specification Ideal Value Marginal Value Ratio of Intensities 1 <100
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
LED Array
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 Pan. LUX Analog Lux Meter • LUX = intensity (lumen/m 2) • Grid constructed over image plane at level where exposure takes place • Light intensity and uniformity measured every 1 x 1 inch • Pinpoint measurements were then taken of the current system – 2 x 2 LED Array – 2 x 3 LED Array
Proof of Concept Intensity (Lux) Intensity Ratio Current System 5600 NA 2 x 2 LED Array 100 56 <100 2 x 3 LED Array 145 39 < 100
Proof of Concept
Mounting System • Array can be contained inside projector casing – Located at bottom or – Located on Small Shelf at height TBD by testing • Larger than 3 x 3 array could pose issue due to size – Modify Projector Case
Bill of Materials Item Number Description Model Number Qty 1 Luxeon Blue LED LXHL-BR 02 4 Pin High Brightness LED 276 -203 4
Risk Assessment Description of Risk Possible Consequences Probability of Risk (H/M/L) Severity of Risk (H/M/L) Overall Risk (H/M/L) Contingency Plan Lead Time if Parts need to be ordered Time Delay L L L Order Ahead Uniform Light Distribution Uneven Exposure H H H Further LED Testing Mounting Current LED System Not Centered and Time L L L Testing Larger LED Array Doesn’t Fit Inside H Projector Case H H Modify Projector Case
Paper Delivery System Ruth Gay
Description • Existing roller system requires manually catching paper after application of toner from roller • Possible risks of manual handling – Shock Short from High Voltage Roller – Pinch Point of Rollers and Pneumatics – Marred Image Quality • Paper Delivery System Solution – Hold 4. 25” x 5. 5” paper samples – Fit in available space
Customer Needs Satisfied and Associated Specifications Customer Need Satisfied Is safe Minimizes user intervention during Transfer Paper Delivery System Specification Human Shock/Short Faults Identified during FMEA Analysis Pinch Point Faults Identified during FMEA Analysis Insufficient or Not Present Warning Labels identified during FMEA Analysis Pass standard “EP Process Test” Ideal Value Marginal Value 0 <5 0 <2 0 <1 N/A
Detailed Drawing/Schematic
Tray Drawing
Right Side Bar Drawing
Left Side Bar Drawing
Cross Bar
Support Leg (x 2)
Proof of Concept
BOM Part P/N Socket Cap Screws 92185 A 991 . 032" Aluminum Sheet 1651 T 11 . 375" Thick Aluminum Sheet 9246 K 23 Aluminum Rod Total Material Cost 6750 K 131 Mat'l Specs 5/32" hex socket, 10 -32 thd, 3/4" stainless steel length, fully threaded, head: dia. 32" ht. 190" 12"x 12", 6061 brushed Aluminum Finish, . 032" Thk 12"x 12", 6061 Unpolished Aluminum finish, . 375" Thk 6061 12" length, Aluminum 1/4" dia. Qty Price Package size 8 $8. 86 25 1 $12. 76 1 1 $31. 98 1 1 $3. 41 1 $57. 01
Risk Assessment Description of Possible Risk Consequences Lead time of Not completed parts soon enough Cost Exceed budget Probability of Risk (H/M/L) M Severity of Risk Overall Risk (H/M/L) M M L M M Contingency Plan Make at in-house shop Change part design to minimize cost, use available stock material
Implementation of High Visibility Warning Signs David Schwartz
Description • Purpose of warning signs – Alert user to specific hazard – Identify how hazard can be avoided • Remove current warning signs • Replace with ISO designed signs • Add new ISO signs where needed
Customer Needs and Associated Specifications Customer Need Satisfied Is Safe Specification Marginal Value Pinch Point Faults <2 Identified during FMEA Analysis Insufficient or Not <1 Present Warning Labels Identified During FMEA Analysis Human Shock/Short <5 Faults Identified during FMEA Analysis Ideal Value 0 0 0
New High Voltage Sign Old High Voltage Sign New High Voltage Sign Actual Height of Sign = 1. 5”
Pinch Point Sign Actual Height of Sign = 1. 5”
System Warning Signs Actual Height of Sign = 1. 25’
Before and After Before After
Proof of Concept • Signs Designed under guidance of ISO-3864 – Establishes the safety identification colors and design principles for safety signs to be used in workplaces and in public areas • Danger - signal word used to indicate an imminently hazardous situation that, if not avoided, will result in death or serious injury – Chosen for High Voltage and Pinch Point • Caution - signal word used to indicate a potentially hazardous situation which, if not avoided could result in minor or moderate injury – Chosen for overall system warning
Size of Signs • ISO Equation: H = D/40 – H = Height of Sign (mm) – D = safe viewing distance (mm) • Pinch Point / Electrical Hazard – Safe Viewing Distance is 5 feet – Results in sign height of 1. 5 inches • Avoid Injury – Safe Viewing Distance of 50 feet – Results in sign height of 1. 25 feet
Other Sign Details • Signs will be placed on both sides of identified hazard areas • Hazard Areas identified during Failure Modes Effect Analysis (FMEA) • Signs will be placed as not to disturb operation and maintenance of machine • Signs made from laminated paper • Signs attached using double sided tape
Risk Assessment Description of Possible Probability of Severity of Overall Risk Contingency Risk Consequences Risk (H/M/L) Plan User Ignores Shock/Short or M M M Assure the Sign Pinch signs are the proper size Signs Detach No sign L L L Attach all present signs securely, print extra
Camera System Andrew Kearns
Description • Purpose is to gain understanding of how image is developed onto photoreceptive material • Photoconductor system stopped • Photoreceptive material imaged after development and before transfer • Nikon D 50 Camera used to Study Process as it occurs • Mirror will reflect image of photoconductor to camera lens
Customer Needs and Associated Specifications Customer Need Satisfied Specification Ideal Value Marginal Value Can Monitor Key Process Parameters Take image the size of PC 9”x 4. 75” 7”x 4”
Camera System in Machine
Proof of Concept • Utilize one of three existing mounts • Third Magnetic Sensor will tell Labview when to stop Photoconductor for image capture • Camera will interface with computer via USB • Labview will call command to Nikon Software to capture image • LED Bar may be removed if paper delivery system occupies too much space
Risk Assessment Description of Risk Possible Consequences Probability of Risk (H/M/L) Camera Space Less space for paper delivery Picture Timing Image L decay on PC Mount is Deterioration unstable H M Severity of Risk (H/M/L) Overall Risk (H/M/L) Contingency Plan M M Use front surface mirrors to Capture a reflected image L L Speed up PC H H New Mounting System
Transfer Roller Speed Measurement Andrew Kearns
Description • Speed of transfer roller critical to timing control and image quality • Need to assure that transfer drum rotates at the same speed as the moving photoconductor as to not elongate/condense the image • Need to assure that the transfer roller will be in the proper position for transfer to paper • Encoder provides feedback as to current speed of drum
Customer Needs Satisfied and Associated Specifications Customer Needs Satisfied Specifications Can Monitor Key % difference Process Parameters between speed of PC and Speed of Drum Ideal Value Marginal Value 0% +/- 5%
Proof of Concept • Optical Encoder sends 1024 pulses / rev
Proof of Concept A & B Outputs of Drum Encoder at 1. 74 k. Hz Measurements Taken for Encoder B Output Signal Vpp 2. 20 E+00 Frequency 1. 74 E+03 Period 5. 74 E-04 Pulse Width+ 2. 82 E-04 Pulse Width- 2. 92 E-04
Risk Assessment Description of Risk Possible Consequences Probability of Risk (H/M/L) Severity of Risk (H/M/L) Overall Risk (H/M/L) Contingency Plan Inability to interface with DAQ Decreased image quality L H M Drive a seven segment display with the encoder output Inability to read A and M outputs Unknown direction of motion H M H Verify proper acquisition of signals
Labview Control Interface Sasha Oliver
Description • Current control system is done via KV 300 PLC • Better solution needed to replace current system with a new user friendly interface • Labview uses dataflow programming to define inputs/outputs and execution sequence of the virtual instrument • Connect devices directly to DAQ to allow for more robust control
Customer Needs Satisfied and Associated Specifications Customer Need Satisfied Specification Ideal Value Marginal Value Can monitor key process parameters Ability to view current status of machine during operation Yes Automation of Parameter Settings UI Includes Automatic and Manual Control of Device Yes Can operate and monitor machine from one interface Ability to control system with current controls and improved controls Yes Easy to learn to use LEEERS Usability Test Result Extremly East to Use Easy to use
UI with Automatic Setting Enabled
UI with Manual Settings Enabled
Proof of Concept
Risk Assessment Description of Risk Interface may not be able to control system as the PLC did The previous state machine is not replicated correctly (incorrect parameters passed into device) Possible Probability of Severity of Consequences Risk (H/M/L) Some parts of M H the system may not work Damaged parts L H Overall Risk (H/M/L) H M Contingency Plan Refine system Refine State machine
Further Issues • • Tilting or Machining the Development System Toner Uniformity Documentation of a user manual Identification of a DAQ for purchase Toner Bias Test Plan with Critical Parameters Table Transfer Roller Height Restriction Air Filtration System
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