Document Revision No.: 1 Revised: 04/06/10 RIT KGCOE MSD Program
P10511 Miniaturization of Xerography
Test Plans & Test Results
By: Derek Meinke, Matthew Liff, Tony Zhang, Zaw Htoo
Table of Contents
1. MSD I: WKS 8-10 Preliminary TEST plan 2
1.1. Introduction; Overview; Summary; Purpose; History, etc. 2
1.2. Project Description; Sub-Systems/ Critical Components Being Tested 2
1.3. Approval; Guide, Sponsor 3
1.4. Test Strategy 4
1.5. Definitions; Important Terminology; Key Words 8
1.6. References 9
2. msd ii WKS 2-3: final test plan 10
2.1. Data Collection Plan; Sampling Plan 10
2.2. Measurement Capability, Equipment 10
2.3. Test Conditions, Setup Instructions 10
2.4. Sponsor/Customer, Site Related, Requests / Considerations 10
2.5. Test Procedure, Work Breakdown Structure, Schedule 10
2.6. Assumptions 11
3. MSD II – WKS 3-10 design test VERIFICATION 12
3.1. Test Results 12
3.2. Logistics and Documentation 12
3.3. Definition of a Successful Test, Pass / Fail Criteria 12
3.4. Contingencies/ Mitigation for Preliminary or Insufficient Results 12
3.5. Analysis of Data – Design Summary 12
3.6. Conclusion or Design Summary 12
3.7. Function/ Performance Reviews 12
3.8. References 12
3.9. Appendices 13
P10511 Miniaturization of Xerography
Test Plans & Test Results
1. MSD I: WKS 8-10 Preliminary TEST plan
1.1. Introduction; Overview; Summary; Purpose; History, etc.
1.1.1. Over the past decade the cost of xerographic digital printer hardware has continued to drop while at the same time print quality, print speed, and reliability has continuously improved. Much of this cost reduction is related to what we will call "The Miniaturization of Xerography". One "figure of merit" gauge of this miniaturization is the size of the photoreceptor required to produce a given print rate, (Pr /PPM). It turns out that when tracked over an extended timeframe, the diameter of photoreceptor drum required to produce a particular print rate has fallen by about a factor of two per decade over the last three decades. The current state requires about a 24mm diameter photoreceptor drum for <40 prints per minute, (ppm), a 40mm diameter photoreceptor drum for > 40ppm, and about an 80mm diameter drum for >80ppm. This miniaturization has been vital to offering low cost digital color printing where the number of printer components is multiplied by the number of colors.
This miniaturization is the result of several innovations and advances in sub-system processes, new materials, and process controls. For example: the wear rate of new photoreceptor materials has dramatically improved, thus allowing smaller photoreceptors to be used, with small photoreceptors other sub-systems followed suit. For example the development sub-systems now use low cost high tolerance rolls and semi-conductive or conductive developers that significantly reduced the waterfront for development subsystems, and finally laser exposure requires much less space than early bulky optical systems.
The photoreceptor charging system has also undergone significant changes over this time frame. The major improvement has been the displacement of bulky high voltage corona emitting devices for compact bias charge rolls (BCR's), particularly for low end office and personal printers. While there are tradeoffs in reliability, cost, size, and footprint for corona vs. BCR devices that ultimately determine selection for any particular printer architecture there continues to be a need for reduced footprint for charging devices, particularly for high speed applications.
1.2. Project Description; Sub-Systems/ Critical Components Being Tested
1.2.1. Project Description: This initial project seeks to design a xerographic charging test fixture that can be used to evaluate these tradeoffs for new emerging and experimental high speed BCR's and compact solid state corona charging devices. The fixture will be fully automated with digital data collection and be used to explore selected experimental charging device configurations and technologies. It will be capable of measuring charging rates on simulated dielectric drums, under numerous critical parameter conditions such as photoreceptor speeds and other spacing and applied voltage set up settings. It will use the waterfront required to charge a photoreceptor to a uniform surface potential per process speed (mm/sec) as its miniaturization figure of merit.
1.2.2. Objective Tree
1.3. Approval; Guide, Sponsor
Approved by:
Team Members: Sign:
Derek Meinke ______
Matthew Liff ______
Tony Zhang ______
Zaw Htoo ______
Guide – Bill Nowak ______
Sponsor – Xerox, Mike Zona ______
1.4. Test Strategy
1.4.1. Product Specifications, Pass/ Fail Criteria, and Block Diagram
Engr. Spec. # / Engineering Specification / Imp. / Source / Specification (description) / Unit of Measure / Marginal Value / Ideal ValueES1 / Charger Gap (1-2mm) / 14% / CN12 / Scorotron charger should be fixed with uniform gap. / mm / 1 - 2 / 1.5
ES2 / Surface Charge (-300 to -800V) / 12% / Implied / Voltage applied to scorotron grid must match the surface bias of P/R / V / -300 to -800 / -300 to -800
ES3 / Surface Speed (≤1m/s) / 11% / CN10 / Photoreceptor drum must be controllable for different speeds. / mm/sec / <1000 / 600
ES4 / Budget ($2k) / 11% / CN14 / The amount of money available for purchasing components. / $ / 2000 / 2000
ES5 / Drum Size (30-84mm) / 11% / CN13 / Drums of different diameters will be provided with known range. / mm / 30 - 84 / 30 - 84
ES6 / Charger Type (BCR or Scorotron) / 10% / CN1 / There are two different chargers we will be focusing on. / N/A / N/A / N/A
ES7 / Uniform Erase Charge (-100V) / 8% / CN9 / After being exposed to the erase lamp, the photoreceptor is expected to have an evenly distributed charge across it. / V / -100 / -100
ES8 / ESV distance (1-2mm) / 8% / CN5 / The distance the ESV is from the outer surface of the photoreceptor. / mm / 1 - 2 / 1.5
ES9 / Dielectric Thickness (~25µm) / 8% / CN3 / Fixture must accommodate photoreceptors with various dielectric thicknesses / µm / 10 / 40
ES10 / Coronode Current
(0-2mA) / 6% / Implied / Constant current delivered to coronode for corona generation. / mA / 0 - 2 / 0 – 2
Engr. Spec. #: enables cross-referencing (traceability) and allows mapping to lower level specs within separate documents
Source: Customer need #, regulatory standard, and/or "implied" (must exist but doesn't have an associated customer need)
Description: quantitative, measureable, testable details
*This table can be expanded to document test results
**Importance percentages only add up to 99%
Pass/Fail Criteria
· ES1: ±0.1mm.
· ES2: ±2V.
· ES3: ±5mm/sec
· ES4: Purchased and gifted costs may exceed $2,000, but purchased costs alone must remain below $2,000.
· ES5: ±0.5mm.
· ES6: 3 different BCR and 3 different Scorotron chargers.
· ES7: ±5V.
· ES8: ±0.1mm.
· ES9: n/a
· ES10: ±15µA
Signal Processing and Flow
1.4.2. Functions (hardware) and Features (software, customer needs)
1. Erase Lamp: Light emitting device that sets the photoreceptor to a near-positive voltage (about -100V)
2. Chargers:
a. Scorotron: Corona-generating apparatus normally consisting of a micron-width wire housed by a metallic shield
b. Bias-Charge Roll: A shaft enveloped in a polymeric material used to apply a voltage onto the photoreceptor via direct contact
3. Electrostatic Voltmeter (ESV): An instrument used to measure voltage by its placement in close proximities with the bias source
4. High-voltage sources:
a. Voltage Source: Outputs a constant voltage
b. Current Source: Outputs a variable voltage in order to maintain a constant current output
5. Stepper Motor: A machine that converts electricity into a mechanical motion
6. Motor Controller: Converts the command signals from the computer’s user interface into electrical signals for operating the motor drive.
7. Motor Drive: Offers dynamic smoothing and antiresonance filters for smooth motion and encoderless stall detection for motor operations
8. Data Acquisition Device (DAQ): Any combination of inputs and outputs used for acquiring electrical measurements and presenting them for data analysis.
9. LabVIEW: A software used for graphical programming for measurement and automation
10. NI Motion: An additional software used in conjunction with LabVIEW for applications in the domain of motor controls
1.4.3. Test Equipment available
1. Multimeter
2. Vernier calipers
3. Gauge blocks
4. Tachometer
1.4.4. Test Equipment needed but not available
1. At this current time, all testing equipment has been accounted for.
1.4.5. Phases of Testing
1.4.5.1. Component/ Device (wks 2-12)
1. Coronode Current Supply / Grid Voltage Supply
2. Motor
3. ESV
4. Erase lamp
5. Photoreceptor
1.4.5.2. Subsystem (wks 6-13)
1. Charger Subsystem
a. ES1: Charger Gap - Gapping block on each end of charger should have a just fit condition between the charger and photoreceptor
i. Take feeler gauges of desired gap, and check both ends and center of charger between charger and photoreceptor
b. ES2: Surface Charge - User’s input for the grid voltage matches with the bias on a photoreceptor within ±2V.
i. Equip a test drum into the fixture
ii. Input a voltage (between 0 to -800V) for the grid bias
iii. Measure the voltage drop between the surface of the test drum and ground using a voltmeter and compare measured value with input bias for grid voltage.
c. ES10: Coronode Current – The output of the current supply for the coronode is within ±15µA of the specified current input
i. Input a current value (0 to 2mA) for the coronode current supply
ii. Channel the analog current output of the current supply to DAQ and measure the actual current value
iii. Compare the input value with actual output of the supply
d. ES7: Charger Type - There are two different chargers we will be focusing on. Both are provided by the customer.
2. Motor Subsystem
a. ES3: Surface Speed - User’s input for surface speed of the photoreceptor should match with the actual surface speed within 5mm/sec
i. Input a surface speed through the LabVIEW interface
ii. While test drum is spinning, apply a tachometer to the surface of the photoreceptor and record the speed
3. ESV Subsystem
a. ES8: ESV Distance – The ESV’s placement is within 1-2 mm of the photoreceptor’s surface
i. Apply a Vplate to the photoreceptor through the graphite brush
ii. Scan the surface charge with the ESV. Desired voltage should be ±2V
iii. Feeler gauges will be used to verify gaps if any voltage variations exist
b. Testing the ESV
i. Apply a voltage to a test drum surface
ii. Scan the drum surface with the ESV
iii. Compare the input voltage with ESV reading and observe the level of noise in the signal.
iv. If any noise is corrupting the signal, add an intermediate filtering step (through LabVIEW) for the ESV signal before processing it for actual use
v. Increase bandwidth of filter as needed until noise clears
4. Erase Subsystem
a. ES7: Uniform Erase Charge – Erase lamp should provide a bias near -100V to the surface of a photoreceptor
i. Equip a test drum into fixture
ii. Allow the photoreceptor to spin at 1m/s and shine the erase lamp onto the test drum
iii. Measure the surface bias with ESV and compare to -100V
Auxiliary Tests (related to Photoreceptor)
5. ES5: Drum Size - Drums of different diameters will be provided with known range.
a. Use vernier calipers to measure actual outer diameter of photoreceptor.
6. ES9: Dielectric Thickness - Thickness will be given from manufacturer.
a. Thickness of dielectric is so miniscule that it will not impact the fixture’s ability to fit the photoreceptors
1.4.5.3. Integration (wks 11-15)
· Summation of tolerances (See Section 1.4.1. Pass/Fail Criteria)
· Verification of calculations and assumptions
a. Cantilever Beam Deflection
δmax=13EIFl3
δmax=0.02 mm
b. Maximum force that Aluminum substrate can withstand without buckling
PCR=π2EIL2
PCR-30mm=16 kip
PCR-84mm=390 kip
· Input/ Output, Signal Processing:
Figure 1.4.5.3.a) Block Diagram for Uniformity Testing (I/O Template)
Figure 1.4.5.3.b) Block Diagram for I-V Slope Testing (I/O Testing)
· Noise problems (ESV signal may contain noise; the signal needs to be cleaned up prior to its analysis using digital filters on the LabVIEW)
· Operation in the darkness (Address our Light Inhibiting Enclosure)
For software, combine test programs you have developed for subsystem testing to communicate between the sub modules by adding one at a time to configure overall system.
• Check the signal integrity and timing
• Check the logic levels and signal waveforms
• On an oscilloscope
1.4.5.4. Reliability (wks 15-20)
· Make sure that charger slides don’t experience wear over time.
· Ensure fasteners are tightened to withstand motor vibrations
1.4.5.5. Customer Acceptance (wks 20-21)
Step 1: Unplug erase lamp, ESV and charger. Remove erase holder from fixture (leaving the erase lamp attached to holder). Remove charger from charger mount. Remove strip of double sided tape from charger mount. Remove charger mount from charger support beam and slide charger support beam to its farthest distance outward from photoreceptor.
Step 2: On the free end of the fixture, remove c-clip, spring retainer plate, spring, end cap and photoreceptor from drive shaft.
Step 3: With no photoreceptor on the drive shaft, remove the ESV from the mounting block. Choose which photoreceptor diameter will be tested. Attach the corresponding mounting block to the ESV guide. Attach the ESV on to the ESV guide, with the appropriate side facing upward.
Step 4: Slide the correct photoreceptor onto the drive shaft, making sure it is concentric around the correct flange on the fixed end cap. Slide end cap onto the free end of the drive shaft, making sure the photoreceptor remains concentric around the correct flange. Slide on spring and retainer plate. Attach the c-clip onto the drive shaft.
Step 5: Place erase holder (with erase lamp attached) into the appropriate slot as determined by the photoreceptor diameter being tested.
Step 6: Place a new strip of double sided tape onto the charger mount. Place charger onto exposed strip of tape, assuring that the charger is mated with the charger mount lip. Slide charger mount (with charger attached) onto the charger support beam, attempting to create tangency between the center line on the charger and the surface of the photoreceptor. Tighten the set screws (x2, located on the back side of the charger support beam) so the charger mount is firmly attached to the charger support beam. For a scorotron charger configuration, continue to step 7. For a BCR charger configuration, skip step 7 and continue to step 8.