Browse Prior Art Database

Pulsed DC Method for Jump Development in EP

IP.com Disclosure Number: IPCOM000121687D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Dodds, CI: AUTHOR [+3]

Abstract

This article describes a method to improve the quality of print produced by non-magnetic monocomponent jump development.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Pulsed DC Method for Jump Development in EP

      This article describes a method to improve the quality of
print produced by non-magnetic monocomponent jump development.

      Jump development with non-magnetic monocomponent toner has
possible advantages for low-end black and color electrophotographic
(EP) printers.  The process can be done with just a DC potential
applied to the developer roll.  A large AC potential riding on a
small DC offset has also been used.  How well toner jumps depends
significantly on toner properties.  Since the toner must meet a
number of materials requirements, it may not always have outstanding
jumping characteristics.  Some toner does not jump well with either
DC (Fig. 1a) or biased AC.  The print quality is correspondingly
poor.  With DC, the print darkness (OD) is so gap dependent that
uniform print cannot be achieved with practical manufacturing
tolerances.  Character definition is also poor.  Biased AC causes
breakdown of the photoconductor (PC) and cannot be used.

      It has been found that a pulsed DC voltage applied to the
developer roll significantly improves print quality. Experience shows
that the potential should meet several criteria:
-    the base voltage should be near the discharged (write) voltage
for the PC;
-    the peak voltage should be beyond the charged (background)
voltage for the PC;
-    the duty cycle should be around 1 to 5%, and
-    the frequency can vary from about 80 Hz to 1 kHz.

      The four parameters can be tuned to optimize the print output.
Consider a 4019 printer modified for jump development.  The preferred
condition at a 60 mm gap with 1.6:1 speed ratio between the developer
and the PC is: -200...