Welcome to Technical Training Induction

OBJECTIVE

By the end of this course you will have completed the

Basic Xerography

Agenda

The Xerographic Process

Charging
Preparing the photoreceptor for accepting the image

Configurations of Photoreceptors

Drum:
Smaller size
No seam
Wider choice of photoconductor materials
No tracking problems
Easier

Corona Charging Devices

Bias Charging Roll

Bias Charging Roll – Pros & cons

Advantages:
Size
Low Ozone emissions
Lower power requirements
Disadvantages:
Limited

Exposing
Capturing the latent image on the photoreceptor

Imaging Devices

Photoreceptor Discharge Mechanism

Development
Toning the latent image

Development

Two Main Schemes:
Single Component Development (SCD)
Toner only
Two Component Development (TCD)
Developer (Toner

Background remains
charged

Why DAD?

Only the area that needs to be developed is exposed

Examples:
Hodaka, A297, 1012, etc.
Several low-end printers

Common Two Component
Development Techniques

Magnetic Brush Development Roll

The conductivity of the carrier determines whether

Examples:
Lakes Family,
Tigris, Nuvera

Transfer
Moving the toned image to paper

Major Transfer Drivers

Toner properties:
Toner shape
Toner size distribution
Tribo
Paper properties:
Electrical properties (surface &

Corona
Biased Transfer Roll
Transfer Belt
Charged Transfer Roll (CTR)
Intermediate Transfer Belt
Acoustic Transfer Assist

Most conventional system
Transfer Assist Blade (TAB) w/ belts applies nip pressure
Corotron

Biased Transfer Roll System

Used in most desktop printers
Conformable nip
Low ozone and

Fields created by charge density on the bias roll
(due to the

Transfer Belt System
Conformable nip w/field tailoring
Low ozone and high

CTR System

Example: Majestik family
Full process color achieved by developing and

Intermediate Belt Transfer System
System approach – build colors on intermediate belt
Dual

Transfer Assist Blade

PreTransfer Baffle

Detack Dicorotron

Transfer Dicorotron

Main Drive Roll

Assist Drive / Stripper Roll

Pretransfer
Discorotron

Transfer System with

Fusing
Fixing the image to paper

Common Fusing Techniques

e. g. Delphax

e. g. Xeikon

e. g. Fujitsu

e. g. Xerox

3 distinct types—all based on a roll pair comprised
of “hard” and

Image-side roll (“fuser” roll) has
non-elastomeric coating
Paper-side roll (“pressure” roll) has

Oil Structure
Non-functional
Simple physical barrier
Functional
Bonds to fusing surface

Oil on sheet: 1 – 30 μliters

Release Agent Applicators - Wick

Wick

Release Agent Applicators - Donor Roll

Metering Blade

Oil on sheet: 1 –

Release Agent Applicators - Web

Oil on sheet: 0.5 - 2 μliters

Pressure

Release Agent Issues

Undesirable feel
Inability to write on the print or to

Stripping aids are required in non-stripping fusers for robustness.

Stripping

Issue: Unacceptable print

Imari-MF Family (Free Belt Nip Fuser)

Fuser Roll

Belt

Pressure
Pad

Erase
Removing the charge from the photoreceptor

Erase

Erase is the process of eliminating any electric memory of the

Cleaning
Removing the residues from the photoreceptor

Types of Residual Materials

Toner
Paper Debris
Fibers
Fillers: Talc, Kaolin (clays), etc.
Adhesives (e.g. ream

Methods of Cleaning Toner

Mechanical Forces
Blade
Multi – Blades
Mechanical Brush
Foam Roll
Web
Electrostatic Forces
Electrostatic Brush
Magnetic

Methods of Cleaning Other Residuals

Disturber Brushes
Paper fibers and debris
Films from toner

Common
Cleaning
Systems

Blade Cleaner

Photoreceptor

Blade

Critical Parameters:
Blade Angle
Force

Pros:
Simple Design
Low Cost

Cons:
P/R Wear
Random failures
Unsuitable for

Mechanical Brush Cleaner

Example: 9000 family

Magnetic Brush Cleaner

Examples: 1075 / 1090

Pros: Effective cleaning
Cons: Cost and life

Electrostatic Brush Cleaner

Pros: Effective cleaning even for spherical toners
Cons: Cost

TONER

Toner in Xerographic Printing Process

Electrophotography (also Xerography – gr. xeros +

From Larger to Smaller by
Uncontrolled Breakage

Conventional: Attrition

Narrow Particle Size Distribution

From Smaller

Irregular shape
Wider distribution
No structure control

Particles from Chemical/EA

Toner

Additive Blending & Packaging

Melt Mixing

Coarse / Fine

Resin

Pigment

Grinding/Jetting

Classification

Polymerization

Conventional Toner Processing

Chemical vs. Conventional