Modeling and simulation of an electrostatic image transfer [Elektronische Ressource] / Rainer Hoffmann

Informations

• Publié par: technische_universitat_munchen
• Publié le: 01 janvier 2004
• Nombre de lectures: 20
• Langue: Deutsch
• Poids de l'ouvrage: 7 Mo

Extrait

Lehrstuhl für Technische Elektrophysik
Technische Universität München
Modeling and Simulation of an Electrostatic Image Transfer
Dipl.-Ing. Univ. Rainer Hoffmann
Vollständiger Abdruck der von der Fakultät für Elektrotechnik und
Informationstechnik der Technischen Universität München zur Erlangung
des akademischen Grades eines
Doktor-Ingenieurs
genehmigten Dissertation.
Vorsitzender: Univ.-Prof. Dr.-Ing J. S. Kindersberger
Prüfer der Dissertation: 1. Univ.-Prof. Dr. rer. nat. G. Wachutka
2. Univ.-Prof. Dr.-Ing. W. Peukert,
Friedrich-Alexander Universität, Erlangen-Nürnberg
Die Dissertation wurde am 24.01.2003 bei der Technischen Universität München
eingereicht und durch die Fakultät für Elektrotechnik und Informationstechnik am
15.07.2004 angenommen.3
Abstract
The various process steps of an electrophotographic printer are modelled to simulate the
whole process from the exposure to the toner deposition on the photoconductor. The main
part consists of a many-body simulation where the complex motion of a large number of toner
particles is calculated by solving the equation of motion, where all relevant forces and the
specific particle properties have been taken into account. The simulation results are calibrated
by comparing them with appropriately simplified experiments prior to the simulation of the
complete real printing process. Based on these simulations, the physical background of the
essential process-specific effects is revealed.
Zusammenfassung
Die verschiedenen Teilschritte des elektrophotographischen Druckprozesses werden mod-
elliert, um eine Simulation des Gesamtprozesses von der Belichtung bis zur Tonerablagerung
auf dem Fotoleiter zu ermöglichen. Den Hauptteil bildet eine Vielteilchensimulation, bei der
die komplexe Bewegung einer großen Menge von Tonerteilchen unter Berücksichtigung aller
relevanten Kräfte sowie der spezifischen Teilcheneigenschaften durch Lösen der Bewegungsgle-
ichungen berechnet wird. Die Simulationsergebnisse werden zuerst im Vergleich mit geeigneten,
vereinfachten Experimenten kalibriert, um dann den kompletten, realen Druckprozess nachzu-
bilden. Mit Hilfe der Simulation lassen sich die physikalischen Hintergründe der wichtigsten
prozeßspezifischen Effekte erklären.45
Meinen Eltern6Contents
1 Introduction and process overview 15
1.1 Motivation.............. ....................... 15
1.2 Processoverview .......... 16
1.2.1 Functionaldescription ... 16
1.2.2 ModelingandSimulation .. 17
1.3 Organizationofthethesis ..... 18
2 Physical properties of the toner 19
2.1 Distributionoftonerdiameter ... ....................... 19
2.2 Distributionoftonercharge .... 20
2.3 Tonersamplesforadhesionmeasurements .................... 21
2.3.1 Thinlayersoftoner..... 23
2.3.2 Thicklayersoftoner .... 24
2.4 Measurementsoftoneradhesionforce ...................... 24
2.4.1 Centrifugemeasurements.. ....................... 25
2.4.2 AFMmeasurements .... 27
2.5 Toner motion under the influence of electric fields................ 28
2.5.1 Setupforelectricfielddetachmentexperiments ............. 28
2.5.2 DCvoltageexperiments . . 29
2.5.3 ACvoltageexperiments . . 31
2.5.4 AC-DCvoltageexperiments ....................... 35
2.5.5 Summary .......... 37
3 Charging and exposure of the photoconductor 39
3.1 Coronachargingprocess ...... 40
3.2 Setupandfunctionalityoftheprinthead..................... 41
3.3 Formandenergyofthelightdots . 41
3.4 Motion of the photoconductor . . . ....................... 42
3.5 Exposure curve of the photoconductor ...................... 42
3.6 Chargedistribution ......... 43
3.7 Potentialcalculation ........ 44
3.8 Summary .............. 45
4 Developer station 47
4.1 Externalfields ............ 48
4.1.1 Airflow ........... ....................... 48
4.1.2 Magneticfield........ 48
4.2 Magneticbrushmany-bodysimulation ...................... 50
4.2.1 Equationofmotion ..... 50
4.2.2 Initialconfiguration 50
78 CONTENTS
4.2.3 Friction force inairflow ................... 51

4.2.4 Carriermagnetization........ 51
4.2.5 Magnetic field force effectedbypermanentmagnets ...... 52


4.2.6 Magnetic field forces causedbycarrier-carrierinteraction .... 52


4.2.7 Results ............... 54
4.3 Stochasticmagneticbrushmodeling .... 55
5 Development nip 59
5.1 Specificationoftheelectricsetup ..... ................... 59
5.2 Airflowinthenip .............. 60
5.3 Electricfieldinthenip ........... 62
5.3.1 StaticFEMcalculation ....... 62
5.3.2 Time-harmonicelectricfield .... 62
5.3.3 Influence of a conductive substrate on the jump roller ......... 63
5.4 Many-bodysimulation............ ................... 64
5.4.1 Equationofmotion ......... 64
5.4.2 Initialconfiguration 65
5.5 Electric field-induced forces ..... 65


5.6 Friction force duetotheparticlemotioninairflow ......... 66

5.7 Boundary-related forces ........... 66
5.7.1 Electric field force causedbyinducedmirrorcharges ...... 66

5.7.1.1 Homogeneously charged sphere near a conductive plane . . . 67
5.7.1.2 Inhomogeneously charged particle near a conductive plane . . 68
5.7.1.3 Mirrorforcesimulationmodel ................ 69
5.7.2 Non-electrostatic adhesion force nearsurfaces ......... 70

5.7.2.1 Theory .......... ................... 70
5.7.2.2 Experimentallyestablisheddependencies ........... 71
5.7.2.3 Simulationmodel .... 71
5.8 Particle-particleinteractions ........ 71
5.8.1 Electric field forces duetoparticle-particleinteraction ....... 71


5.8.2 Short-range cohesion forces . 72

5.8.3 Collision incidents.......... ................... 74
5.8.3.1 Partlyelasticimpactofaparticleonasurface ........ 74
5.8.3.2 Partlyelasticparticle-particlescattering ........... 75
5.8.3.3 Fast impact between toner particles: momentum transfer . . 75
5.8.3.4 Positionafterfastimpact 77
5.9 Integrationmodule ............. 77
5.9.1 Higher-ordermethods........ ................... 77
5.9.2 Influenceofdiscontinuousforcefunctions ................ 80
5.9.3 Comparisonoftheappliedforces.. 81
5.10 Summary .................. 82
6 Simulation sequence 83
6.1 Usedsoftwarepackages ........... ................... 83
6.2 Mainflowchart ............... 84
6.3 Parallelization ................ 85
6.4 Datahandling 88
6.4.1 Gridstorage............. 88
6.4.2 Interpolationofapreviouslycalculatedandstoredfieldmap ...... 88
6.4.3 Transformationofcoordinatesystems .................. 89