Processing

Please wait...

Settings

Settings

Goto Application

1. WO2002020271 - DIRECT ELECTROSTATIC PRINTING METHOD AND APPARATUS

Publication Number WO/2002/020271
Publication Date 14.03.2002
International Application No. PCT/SE2000/001722
International Filing Date 07.09.2000
Chapter 2 Demand Filed 05.04.2002
IPC
B41J 2/415 2006.01
BPERFORMING OPERATIONS; TRANSPORTING
41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
2Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
385characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material
41for electrostatic printing
415by passing charged particles through a hole or a slit
CPC
B41J 2/4155
BPERFORMING OPERATIONS; TRANSPORTING
41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, ; e.g. INK-JET PRINTERS, THERMAL PRINTERS; , i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
2Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
385characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material
41for electrostatic printing
415by passing charged particles through a hole or a slit
4155for direct electrostatic printing [DEP]
Applicants
  • ARRAY AB (publ) [SE]/[SE] (AllExceptUS)
  • KLOCKAR, Per [SE]/[SE] (UsOnly)
  • STARCK-JOHNSON, Hans-Peter [SE]/[SE] (UsOnly)
Inventors
  • KLOCKAR, Per
  • STARCK-JOHNSON, Hans-Peter
Agents
  • BERGENTALL, Annika
Priority Data
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) DIRECT ELECTROSTATIC PRINTING METHOD AND APPARATUS
(FR) PROCEDE ET APPAREIL D'IMPRESSION ELECTROSTATIQUE DIRECTE
Abstract
(EN)
A direct electrostatic printing device and method for printing an image with improved macro conformity. It has been discovered that printing devices comprising printhead structures, with a semi conducting layer exhibits a memory effect, i.e. a current printing is influenced by what has been printed previously. According to the invention it has further been discovered that this memory effect is caused by charge build-up on the semi conducting layer around each aperture, this due to the long time constant of the semi conducting layer and to symmetry of the print pulses. The print pulses on the control electrodes are unsymmetrical in dependence as to what is printed and within a print sequence an average voltage value is not at a desired level. According to the invention charge build-ups on the semi conducting layer is prevented or at leased lessened, at least from print cycle to print cycle and preferably from print sequence to print sequence. A preferred embodiment comprises selectively adding mirror pulses to the control electrodes to attain a desired average voltage value independently of what is printed.
(FR)
L'invention concerne un dispositif et un procédé d'impression électrostatique directe permettant d'imprimer une image ayant une meilleure conformité macro. On s'est rendu compte que les dispositifs d'impression ayant des structures tête d'impression pourvues d'une couche semi-conductrice ont un effet mémoire, c'est-à-dire qu'une impression actuelle est influencée par l'impression précédente. Selon l'invention, on s'est aperçu que cet effet mémoire est dû à la formation de charge sur la couche semi-conductrice autour de chaque ouverture en raison de la constante longue durée de la couche semi-conductrice et de la symétrie des impulsions d'impression. Les impulsions d'impression sur les électrodes de commande sont asymétriques en fonction de ce qui est imprimé et, dans une séquence d'impression, une valeur moyenne de tension n'est pas à un niveau souhaité. Selon l'invention, les formations de charge sur la couche semi-conductrice sont empêchées ou au moins réduites, au moins d'un cycle d'impression à l'autre et, de préférence, d'une séquence d'impression à l'autre. Un mode de réalisation préféré comprend l'addition sélective d'impulsions miroir aux électrodes de commande pour obtenir la valeur de tension moyenne souhaitée indépendamment de ce qui est imprimé.
Also published as
Latest bibliographic data on file with the International Bureau